U.S. patent application number 14/203028 was filed with the patent office on 2014-09-18 for methods and systems for converting plastic to fuel.
This patent application is currently assigned to Natural State Research, Inc.. The applicant listed for this patent is Natural State Research, Inc.. Invention is credited to Moinuddin Sarker.
Application Number | 20140275667 14/203028 |
Document ID | / |
Family ID | 51530214 |
Filed Date | 2014-09-18 |
United States Patent
Application |
20140275667 |
Kind Code |
A1 |
Sarker; Moinuddin |
September 18, 2014 |
METHODS AND SYSTEMS FOR CONVERTING PLASTIC TO FUEL
Abstract
A method for producing a vapor stream from waste plastic
comprises providing a waste plastic feedstock into a reactor
containing one or more residues produced from a previously heated
source of waste plastic, and heating the waste plastic feedstock in
the reactor to a temperature from about 125.degree. C. to
500.degree. C. to generate a vapor containing one or more
hydrocarbons. The waste plastic feedstock can have a calcium to
sodium mass ratio from about 0.0001 to 400 as measured by
inductively-coupled plasma (ICP) spectrometry. The catalytic
activity in the reactor may be provided through one or more
constituent elements in the waste plastic feedstock or the one or
more residues produced from the previously heated source of waste
plastic.
Inventors: |
Sarker; Moinuddin;
(Bridgeport, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Natural State Research, Inc. |
Pawling |
NY |
US |
|
|
Assignee: |
Natural State Research,
Inc.
Pawling
NY
|
Family ID: |
51530214 |
Appl. No.: |
14/203028 |
Filed: |
March 10, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61784725 |
Mar 14, 2013 |
|
|
|
Current U.S.
Class: |
585/241 |
Current CPC
Class: |
C10G 1/10 20130101 |
Class at
Publication: |
585/241 |
International
Class: |
C10G 1/10 20060101
C10G001/10 |
Claims
1. A method for producing a condensate from waste plastic,
comprising: a. providing a waste plastic feedstock into a reactor
containing one or more residues produced from a previously heated
source of waste plastic, wherein the waste plastic feedstock
includes at least one of a tire and an electrical component casing,
and wherein said residue has a calcium-to-sodium mass ratio from
about 0.0001 to 400 as measured by inductively-coupled plasma (ICP)
spectrometry; b. heating said waste plastic feedstock in said
reactor to a temperature from about 125.degree. C. to 500.degree.
C. to generate a vapor containing one or more hydrocarbons; c.
condensing said vapor to generate said condensate comprising said
one or more hydrocarbons; and d. collecting said condensate in a
collection vessel, wherein said condensate comprises between about
20 g and 75 g of said one or more hydrocarbons per 100 g of said
waste plastic and said one or more residues.
2. The method of claim 1, wherein said waste plastic feedstock is
heated in said reactor without any added external catalyst.
3. The method of claim 1, wherein said waste plastic feedstock
comprises one or more elements selected from aluminum, antimony,
arsenic, barium, beryllium, bismuth, boron, cadmium, calcium,
cesium, chromium, cobalt, copper, gallium, germanium, gold,
hafnium, indium, iron, lead, lithium, magnesium, manganese,
mercury, molybdenum, nickel, platinum, palladium, potassium,
rhodium, iridium, osmium, ruthenium, rhenium, rubidium, scandium,
selenium, silicon, silver, sodium, strontium, tantalum, tellurium,
thallium, thorium, tin, titanium, tungsten, vanadium, zinc, and
zirconium.
4. The method of claim 1, wherein said waste plastic feedstock
comprises two or more of said elements.
5. The method of claim 1, wherein said waste plastic feedstock
comprises three or more of said elements.
6. The method of claim 1, wherein said waste plastic feedstock
comprises four or more of said elements.
7. The method of claim 1, wherein said waste plastic feedstock
comprises five or more of said elements.
8. The method of claim 1, wherein said calcium to sodium mass ratio
is from about 0.005 to 400, as measured by ICP.
9. The method of claim 1, wherein said calcium to sodium mass ratio
is from about 0.0001 to 4, as measured by ICP.
10. The method of claim 1, wherein said calcium to sodium mass
ratio is from about 0.0001 to 0.04, as measured by ICP.
11. The method of claim 1, wherein said residue comprises one or
more elements selected from aluminum, antimony, arsenic, barium,
beryllium, bismuth, boron, cadmium, calcium, cesium, chromium,
cobalt, copper, gallium, germanium, gold, hafnium, indium, iron,
lead, lithium, magnesium, manganese, mercury, molybdenum, nickel,
platinum, palladium, potassium, rhodium, iridium, osmium,
ruthenium, rhenium, rubidium, scandium, selenium, silicon, silver,
sodium, strontium, tantalum, tellurium, thallium, thorium, tin,
titanium, tungsten, vanadium, zinc, and zirconium.
12. The method of claim 11, wherein said residue comprises two or
more of said elements.
13. The method of claim 11, wherein said residue comprises three or
more of said elements.
14. The method of claim 11, wherein said residue comprises four or
more of said elements.
15. The method of claim 11, wherein said residue comprises five or
more of said elements.
16. The method of claim 11, wherein said calcium to sodium mass
ratio is from about 0.003 to 40, as measured by ICP.
17. The method of claim 11, wherein said calcium to sodium mass
ratio is from about 0.003 to 4, as measured by ICP.
18. The method of claim 11, wherein said calcium to sodium mass
ratio is from about 0.0001 to 0.04, as measured by ICP.
19. The method of claim 1, wherein said temperature is from about
150.degree. C. to 410.degree. C.
20. The method of claim 1, wherein said temperature is from about
125.degree. C. to 375.degree. C.
21. The method of claim 1, further comprising one or more
pre-processing steps selected from the group consisting of
collection processes, sorting processes, size reduction processes,
cleaning processes, drying processes, and weighing processes.
22. The method of claim 1, further comprising one or more
post-processing steps selected from the group consisting of
collection processes, sorting processes, size reduction processes,
cleaning processes, drying processes, and weighing processes.
23. The method of claim 1, wherein said plastic feedstock is
obtained from at least one source selected from a landfill,
recycling center, waste processing facility, a household, a
place-of-business, an eating establishment, an automotive salvage
yard, an aircraft salvage yard, or a ship salvage yard.
24. The method of claim 1, wherein said waste plastic feedstock
further comprises high density polypropylene (HDPE), low density
polypropylene (LDPE), polypropylene (PP), polystyrene (PS),
polyvinylchloride (PVC), polyethylene terephthalate (PETE),
synthetic rubber, and/or natural rubber.
25. The method of claim 1, wherein said one or more hydrocarbons
include alcohols, aldehydes, ketones, alkanes, alkenes, alkynes,
and/or carboxylic acids.
26. The method of claim 1, wherein said electrical component casing
comprises a computer body or an electrical cable casing.
27. The method of claim 1, wherein said tire is a rubber tire.
Description
CROSS-REFERENCE
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 61/784,725, filed Mar. 14, 2013, said
application is incorporated herein by reference in its entirety for
all purposes.
BACKGROUND
[0002] Fuel is any material that stores energy that can later be
extracted to perform mechanical work in a controlled manner. At
least some fuels presently used undergo combustion, a redox
reaction in which a combustible substance releases energy after it
ignites and reacts with the oxygen in the air. Other processes used
to convert fuel into energy include various other exothermic
chemical reactions and nuclear reactions, such as nuclear fission
or nuclear fusion. Fuels are also used in the cells of organisms in
a process known as cellular respiration, where organic molecules
are oxidized to release usable energy. Hydrocarbons are the most
common source of fuel presently used, but other substances,
including radioactive metals, are also utilized.
[0003] While there are methods currently available for generating
fuel, there are drawbacks to such methods. For instance, methods
presently available may require a considerable amount of energy to
produce fuel.
SUMMARY
[0004] The disclosure provides methods and systems for the
conversion of waste plastic to lower molecular weight hydrocarbon
materials, particularly valuable hydrocarbon materials such as
hydrocarbon fuel materials. Methods and systems of the disclosure
provide for the decomposition of hydrocarbon polymers of waste
plastics, which can have a high molecular weights (i.e., long
carbon-chain lengths), to lower molecular-weight hydrocarbons
(i.e., shorter carbon-chain lengths) that may be useful as
fuels.
[0005] Producing fuel and other valuable low molecular weight
hydrocarbon materials from the thermal decomposition of waste
plastic may have environmental benefit both with respect to less
reliance on traditional fuel production processes that may generate
pollution and reduced levels of plastic wasted sent to landfills.
Fuel production from decomposed waste plastic may also have
advantages over other current alternative fuel sources, such as for
instance crop-plant biomass fuels (bio-fuels) and wind generators.
Such alternative methods may have drawbacks, including (a) the
diversion of crop-producing resources (including arable land) from
food production to fuel production, (b) the re-engineering of
machinery that is often required in order to run on bio-fuels and
(c) the harmful penetration of, for example, equipment into air
spaces normally inhabited by wildlife. As an example, the danger of
windmills to birds has been well-documented, particularly when
windmills are placed along major migratory routes. Economic
advantages may also be achieved from an alternative source of
hydrocarbon fuels in light of the currently rising costs of
hydrocarbon fuels, such as, for example, the significant increase
in the cost of gasoline during the last decade.
[0006] An aspect of the disclosure provides a method for producing
a vapor stream from waste plastic. The method comprises providing a
waste plastic feedstock into a reactor containing one or more
residues produced from a previously heated source of waste plastic,
wherein the waste plastic feedstock includes at least one of a tire
and an electrical component casing, and wherein the residue has a
calcium-to-sodium mass ratio from about 0.0001 to 400 as measured
by inductively coupled plasma (ICP) spectrometry; heating the waste
plastic feedstock in the reactor to a temperature from about
125.degree. C. to 500.degree. C. to generate a vapor containing one
or more hydrocarbons; condensing the vapor to generate the
condensate comprising the one or more hydrocarbons; and collecting
the condensate in a collection vessel, wherein the condensate
comprises between about 20 g and 75 g of the one or more
hydrocarbons per 100 g of the waste plastic and the one or more
residues. The waste plastic feedstock can be heated in the reactor
without any added external catalyst.
[0007] The waste plastic feedstock may comprise one or more
elements selected from aluminum, antimony, arsenic, barium,
beryllium, bismuth, boron, cadmium, calcium, cesium, chromium,
cobalt, copper, gallium, germanium, gold, hafnium, indium, iron,
lead, lithium, magnesium, manganese, mercury, molybdenum, nickel,
platinum, palladium, potassium, rhodium, iridium, osmium,
ruthenium, rhenium, rubidium, scandium, selenium, silicon, silver,
sodium, strontium, tantalum, tellurium, thallium, thorium, tin,
titanium, tungsten, vanadium, zinc, and zirconium. Alternatively,
the waste plastic feedstock comprises two, three, four, five, or
more of the elements.
[0008] The calcium to sodium mass ratio may be from about 0.0001 to
4 or from about 0.0001 to 0.04 as measured by ICP.
[0009] The residue may comprise one or more elements selected from
aluminum, antimony, arsenic, barium, beryllium, bismuth, boron,
cadmium, calcium, cesium, chromium, cobalt, copper, gallium,
germanium, gold, hafnium, indium, iron, lead, lithium, magnesium,
manganese, mercury, molybdenum, nickel, platinum, palladium,
potassium, rhodium, iridium, osmium, ruthenium, rhenium, rubidium,
scandium, selenium, silicon, silver, sodium, strontium, tantalum,
tellurium, thallium, thorium, tin, titanium, tungsten, vanadium,
zinc, and zirconium. Alternatively, the waste plastic feedstock
comprises two, three, four, five, or more of the elements. In cases
where the residue comprises one of the elements, the calcium to
sodium mass ratio may be from about 0.003 to 40, from about 0.003
to 4, or from about 0.0001 to 0.04, as measured by ICP.
[0010] The temperature can be from about 150.degree. C. to
410.degree. C. or from about 125.degree. C. to 375.degree. C.
[0011] Moreover, the method may include one or more pre-processing
steps selected from the group consisting of collection processes,
sorting processes, size reduction processes, cleaning processes,
drying processes, and weighing processes. Additionally, the method
may include one or more post-processing steps selected from the
group consisting of collection processes, sorting processes, size
reduction processes, cleaning processes, drying processes, and
weighing processes.
[0012] The waste plastic feedstock may be obtained from at least
one source selected from a landfill, recycling center, waste
processing facility, a household, a place-of-business, an eating
establishment, an automotive salvage yard, an aircraft salvage
yard, or a ship salvage yard. Furthermore, the waste plastic
feedstock further may comprise high density polypropylene (HDPE),
low density polypropylene (LDPE), polypropylene (PP), polystyrene
(PS), polyvinylchloride (PVC), polyethylene terephthalate (PETE),
synthetic rubber, and/or natural rubber.
[0013] Hydrocarbons may include alcohols, aldehydes, ketones,
alkanes, alkenes, alkynes, and/or carboxylic acids.
[0014] An electrical component casing may comprise a computer body
or an electrical cable casing.
[0015] A tire may be a rubber tire.
[0016] Additional aspects and advantages of the present disclosure
will become readily apparent to those skilled in this art from the
following detailed description, wherein only illustrative
embodiments of the present disclosure are shown and described. As
will be realized, the present disclosure is capable of other and
different embodiments, and its several details are capable of
modifications in various obvious respects, all without departing
from the disclosure. Accordingly, the drawings and description are
to be regarded as illustrative in nature, and not as
restrictive.
INCORPORATION BY REFERENCE
[0017] All publications, patents, and patent applications mentioned
in this specification are herein incorporated by reference to the
same extent as if each individual publication, patent, or patent
application was specifically and individually indicated to be
incorporated by reference.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The novel features of the invention are set forth with
particularity in the appended claims. A better understanding of the
features and advantages of the disclosure will be obtained by
reference to the following detailed description that sets forth
illustrative embodiments, in which the principles of the invention
are utilized, and the accompanying drawings of which:
[0019] FIG. 1 schematically illustrates a method for generating
volatiles from waste plastic.
[0020] FIG. 2 provides an example metal elemental analysis of waste
plastic feedstocks for several common types of plastic found in
waste plastics. As a reference, the elemental composition of a
standard source (e.g., high purity plastic obtained from a chemical
supply company) of each type of plastic analyzed is shown.
[0021] FIG. 3 provides an example metal elemental analysis for a
residue generated from heated waste plastic feedstocks that are
comprised of a single type of plastic. As a reference, the
elemental composition of a residue generated from a standard source
(e.g., high purity plastic obtained from a chemical supply company)
of each type of analyzed plastic is shown.
[0022] FIG. 4 schematically illustrates the process-flow of an
example method of the disclosure that is executed in batch
mode.
[0023] FIG. 5 schematically illustrates the process-flow of an
example method of the disclosure that is executed in continuous
mode.
[0024] FIG. 6 schematically illustrates an example system of the
disclosure capable of executing a method of the disclosure in batch
mode.
[0025] FIG. 7 schematically illustrates an example system of the
disclosure capable of executing a method of the disclosure in batch
or continuous mode.
DETAILED DESCRIPTION
[0026] While various embodiments of the invention have been shown
and described herein, it will be obvious to those skilled in the
art that such embodiments are provided by way of example only.
Numerous variations, changes, and substitutions may occur to those
skilled in the art without departing from the invention. It should
be understood that various alternatives to the embodiments of the
invention described herein may be employed.
[0027] The term "plastic," as used herein, generally refers to a
polymeric material, made in whole, or part, of at least one
hydrocarbon, that may contain one or more modifications and/or may
be compounded with an additive (e.g., colorants, plasticizers,
etc.) to form a useful material. An example of a plastic is
high-density polyethylene (HDPE).
[0028] The term "waste plastic," as used herein, generally refers
to a post-consumer plastic that is no longer needed for its
intended purpose. Waste plastics may be generated from a range of
consumer products. An example of a waste plastic is high density
polyethylene (HDPE) that is a material component of an empty,
one-gallon milk container.
[0029] The term "waste plastic feedstock," as used herein,
generally refers to an aggregate of waste plastic that may be
processed to generate additional useful materials. Non-limiting
examples of a waste plastic feedstock include a single empty,
one-gallon milk container a lot of 100 empty, one-gallon milk
containers comprised of high-density polyethylene (HDPE).
[0030] The term "thermal decomposition," as used herein, generally
refers to a process in which higher molecular-weight polymeric
materials may be broken down into materials of lower
molecular-weight with sustained heating or heating at increasing
temperature. An example of thermal decomposition is the heating of
a waste plastic feedstock to produce lower molecular-weight
materials.
[0031] The term "residue," as used herein, generally refers to
residual material, comprised, at least in part, of lower
molecular-weight hydrocarbons and/or materials of a waste plastic
feedstock, which does not volatilize during thermal decomposition
of a waste plastic feedstock.
[0032] The term "lower molecular-weight hydrocarbon," as used
herein, generally refers to a hydrocarbonaceous species of lower
carbon-chain length that is produced by thermally decomposing a
hydrocarbonaceous species of higher carbon-chain length. An example
of a lower molecular-weight hydrocarbon is octane produced from the
thermal decomposition of a waste plastic feedstock comprised of
higher molecular-weight hydrocarbonaceous materials.
[0033] The term "external catalyst," as used herein, generally
refers to a material that speeds-up the kinetics of waste plastic
feedstock thermal decomposition and is not a material component of
a waste plastic feedstock being heated; a residue, generated from a
previously heated waste plastic feedstock, that is heated with the
waste plastic feedstock being heated; or any apparatus or device
used to contain a waste plastic feedstock and/or residue during
heating. An example of an external catalyst is a noble metal on a
support that is added to a reactor to facilitate a chemical
reaction.
[0034] The term "internal catalyst," as used herein, generally
refers to a material that speeds-up the kinetics of waste plastic
feedstock thermal decomposition and is a material component of a
waste plastic feedstock being heated; a residue, generated from a
previously heated waste plastic feedstock that is heated with the
waste plastic feedstock being heated; or any apparatus or device
used to contain a waste plastic feedstock and/or residue during
heating. An example of an internal catalyst is a noble metal that
is a material component of a waste plastic feedstock that is
entered into a reactor.
[0035] The term "chemical additive," as used herein, generally
refers to an agent that improves thermal decomposition, either
catalytically or non-catalytically. In some cases, a chemical
additive may also be an external catalyst. An example of a chemical
additive is calcium hydroxide.
[0036] The term "optimum temperature," as used herein, generally
refers to the temperature at which maximum levels of
hydrocarbonaceous distillate may be obtained during thermal
decomposition of a waste plastic feedstock.
[0037] The term "mass conversion," as used herein, generally refers
to the ratio of the mass of liquid lower molecular-weight
hydrocarbon distillate recovered during thermal decomposition of a
waste plastic feedstock to the mass of waste plastic feedstock
entered into the reactor multiplied by one hundred percent.
[0038] The present disclosure provides methods and systems for the
conversion of waste plastic to lower molecular-weight hydrocarbon
materials, such as, for example, valuable hydrocarbon materials
such as hydrocarbon fuel materials. The present disclosure provides
systems and methods for the decomposition of hydrocarbon polymers
of waste plastics, which have high molecular-weights (i.e., long
carbon-chain lengths), to lower molecular-weight hydrocarbons
(i.e., shorter carbon-chain lengths), particularly those useful as
fuels.
[0039] FIG. 1 shows a process flow diagram 100 that comprises the
steps of: (a) entering a waste plastic feedstock into a reactor
105; (b) heating, at increasing temperature and in the presence of
a residue generated from a previously heated waste plastic
feedstock, a waste plastic feedstock to induce thermal
decomposition of the waste plastic feedstock 110; (c) distillation
of volatilization of lower molecular-weight hydrocarbons that may
be released from thermal decomposition of the waste plastic
feedstock 115; (d) condensation of a lower molecular-weight
hydrocarbon vapor stream formed from the volatilization 120; and,
optionally, (f) further refinement of the liquid distillate by one
or more separation means 125. In some situations, thermal
decomposition of hydrocarbon polymers is effected without the use
of an external catalyst. Instead, waste plastics and/or residues
generated from them may contain a host of metals in addition to
hydrocarbon polymers. One or more of such metals of a waste plastic
feedstock and/or a residue may serve as an internal catalyst for
thermal decomposition of the waste plastic feedstock during
heating. Metals of any apparatus or device used to contain a waste
plastic feedstock and/or residue may also participate in thermal
decomposition catalysis.
[0040] The disclosure also provides systems that may be utilized to
execute methods provided by the disclosure. In general, systems of
the disclosure are broadly comprised of a) at least one reactor
that contains a residue generated from at least one previously
heated waste plastic feedstock; b) at least one heating source; and
c) at least one condenser.
Waste Plastics
[0041] Waste plastic may be generated from a range of consumer
products. In a non-limiting example, a waste plastic may be
generated from a post-consumer plastic container with non-limiting
examples that include: food storage containers, food storage
wrappers, personal hygiene product containers, beauty product
containers, household chemical containers, personal hygiene
chemical containers, automotive chemical containers, plastic bags,
and waste receptacles. Other non-liming examples of a waste plastic
include post-consumer plastic food utensils, plastic product
packaging devices, plastic automotive components, electrical
component casings (e.g., computer body, electrical cable casings),
tires (including rubber tires), personal protective equipment (e.g.
protective gloves), plastic toys, plastic household furnishings,
and plastic piping. As a waste plastic is considered refuse, common
non-limiting examples of establishments from which a waste plastic
may be obtained include a private or public waste processing
facility, a private or public landfill, a household, a
place-of-business, an eating establishment, an automotive,
aircraft, or ship salvage yard, or a private or public recycling
center.
[0042] A waste plastic may be comprised of a thermoplastic or a
thermoset polymer. Thermoplastic polymers may be resilient species
that may become pliable and moldable at higher temperatures, yet
return to the same solid state of the material prior to heating
when cooled. Thermoplastics may be higher molecular-weight (e.g.,
long polymer chains) materials whose chains associate through
non-covalent intermolecular forces (e.g., Van der Waals forces,
hydrophobic interactions, etc.). Moreover, the polymer chains of a
thermoplastic may be linear or slightly branched in shape. The
strength of interchain interactions is reduced during heating, and
regained during cooling, permitting a return to the solid state of
the material prior to heating. In contrast, thermoset polymers may
undergo a chemical change when they are heated, and cannot be
returned to their pre-heated solid state. The irreversible nature
of a thermoset after heating is due to intermolecular covalent
bonds that form between polymer chains during heating.
[0043] Methods provided herein may be executed with most types of
waste plastic feedstocks. A waste plastic feedstock utilized in
methods provided herein may be comprised of a single type of waste
plastic or may be comprised of a combination of two or more types
of waste plastic. Non-limiting examples of the types of plastic
that may be found in a waste plastic feedstock include
thermoplastic polymers, thermoset polymers, low-density
polyethylene (LDPE), high-density polyethylene (HDPE),
polypropylene (PP), polystyrene (PS), polyethylene terephthalate
(PETE), polyvinyl chloride (PVC), synthetic rubber, natural rubber,
and combinations thereof. Several of these example plastics have
been classified by the American Plastic Council for aiding in
plastic identification during recycling processes. Code 1
identifies PETE, with non-limiting examples of its use that include
beverage containers and waterproof packaging. Code 2 identifies
HDPE, with non-limiting examples of its use that include milk,
detergent and oil bottles, toys, and plastic bags. Code 3
identifies vinyl/polyvinyl chloride (PVC), with non-limiting
examples of its use that include food wrap, vegetable oil bottles,
blister packages, and piping. Special considerations must be given
to PVC as it contains bonded chlorine atoms which, upon degradation
of the polymer, must be separated and handled according to material
safety protocols. Code 4 is LDPE, with non-limiting examples of its
use that include plastic bags, shrink wrap, and garment bags. Code
5 is PP, with non-limiting examples of its use that include
refrigerated containers, plastic bags, bottle tops, carpets and
food wraps. Code 6 is PS, which is often used for disposable
utensils, meat packing, Styrofoam, and protective packing
materials. Code 7 describes "other" plastics (i.e., those not
described with codes 1-6), with non-limiting examples that include
layered plastic, mixed plastic, polycarbonate (PC), and
acrylonitrile-butadiene-styrene (ABS). While the plastic numbering
system may be readily recognized by consumers and waste processing
professionals alike, a great number of additional plastic types
exist beyond those identified by the numbering system and may also
be considered useful in methods of the disclosure.
[0044] Waste plastics may be generally classified by the primary
polymer or polymers of which they may be comprised. Like most other
materials, however, waste plastics may also contain additional
chemical species that may include plastic additives to enhance
mechanical properties (e.g., tensile strength, stiffness, etc.) or
alter cosmetic appearance (e.g., colorants). Waste plastics may
also contain unintended impurities that may include trace or bulk
quantities of a metal. Such impurities may be impregnated into a
waste plastic material, for example, during manufacturing of the
plastic material. Alternatively, as another example, impurities may
have been impregnated or adhered to a waste plastic material by
contaminant mixing events that occur at a waste processing or
recycling facility after waste collection.
[0045] FIG. 2 shows an example elemental analysis, which is
conducted via inductively coupled plasma optical emission
spectroscopy (ICP-OES) and probes a panel of metal elements, for
several types (e.g., HDPE, LDPE, PP, and PS) of waste plastic.
Standard samples of plastic (i.e., a high purity sample of a
respective plastic obtained directly from a chemical supply
company) are also tested as a reference. It is evident from FIG. 2
that each type of plastic tested is comprised, in part, of metals
and that samples that originate in a waste plastic may be comprised
of higher levels of metals than their high-purity, standard
counterparts.
[0046] As a residue is, at least in part, comprised of materials
that once comprised a waste plastic feedstock, the residue may
contain some of the same additive materials or unintended
impurities (e.g., metals) that may be detected in a waste plastic
feedstock. FIG. 3 shows an example elemental analysis, which is
conducted via inductively coupled plasma optical emission
spectroscopy (ICP-OES) and probes a panel of metal elements, for
several residues generated from heating several types (e.g., HDPE,
LDPE, PP, and PS) of waste plastic. Residues generated from
standard samples of plastic (i.e., a high purity sample of a
respective HDPE plastic obtained directly from a chemical supply
company) are also tested as a reference. It is evident from FIG. 3
that each type of residue tested is comprised of metals and that
residues that originate from a waste plastic may be comprised of
higher levels of metals than residues from higher-purity
standards.
[0047] Non-limiting examples of metals that may, at least in part,
be a component of a waste plastic feedstock or a residue and may be
measurable by ICP-OES include: aluminum, antimony, arsenic, barium,
beryllium, bismuth, boron, cadmium, calcium, cesium, chromium,
cobalt, copper, gallium, germanium, gold, hafnium, indium, iron,
lead, lithium, magnesium, manganese, mercury, molybdenum, nickel,
platinum, palladium, potassium, rhodium, iridium, osmium,
ruthenium, rhenium, rubidium, scandium, selenium, silicon, silver,
sodium, strontium, tantalum, tellurium, thallium, thorium, tin,
titanium, tungsten, vanadium, zinc, and zirconium.
[0048] In some instances, a waste plastic feedstock or residue may
be comprised of all of following elements: aluminum, antimony,
arsenic, barium, beryllium, bismuth, boron, cadmium, calcium,
cesium, chromium, cobalt, copper, gallium, germanium, gold,
hafnium, indium, iron, lead, lithium, magnesium, manganese,
mercury, molybdenum, nickel, platinum, palladium, potassium,
rhodium, iridium, osmium, ruthenium, rhenium, rubidium, scandium,
selenium, silicon, silver, sodium, strontium, tantalum, tellurium,
thallium, thorium, tin, titanium, tungsten, vanadium, zinc, and
zirconium. In some examples, a waste plastic feedstock or residue
may be comprised of at least one of the above elements. In some
examples, a waste plastic feedstock or residue may be comprised of
at least two of the above elements. In some examples, a waste
plastic feedstock or residue may be comprised of at least three of
the above elements. In some examples, a waste plastic feedstock or
residue may be comprised of at least four of the above elements. In
some examples, a waste plastic feedstock or residue may be
comprised of at least five of the above elements. In some examples,
a waste plastic feedstock or residue may be comprised of 6, 7, 8,
9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42,
43, 44, 45, 46, 47, 48, 49, or 50 of the above elements. In some
examples, a waste plastic feedstock or residue may be comprised of
at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34,
35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50
of following elements: aluminum, antimony, arsenic, barium,
beryllium, bismuth, boron, cadmium, calcium, cesium, chromium,
cobalt, copper, gallium, germanium, gold, hafnium, indium, iron,
lead, lithium, magnesium, manganese, mercury, molybdenum, nickel,
platinum, palladium, potassium, rhodium, iridium, osmium,
ruthenium, rhenium, rubidium, scandium, selenium, silicon, silver,
sodium, strontium, tantalum, tellurium, thallium, thorium, tin,
titanium, tungsten, vanadium, zinc, and zirconium.
[0049] In some situations, a waste plastic feedstock may contain
levels, measurable by ICP-OES, of the metals calcium and sodium. In
some examples, the mass ratio of calcium to sodium in a waste
plastic feedstock may be from about 0.0001 to 400. In some
examples, the mass ratio of calcium to sodium in a waste plastic
feedstock may be from about 0.005 to 400. In some examples, the
mass ratio of calcium to sodium in a waste plastic feedstock may be
from about 0.005 to 280. In some examples, the mass ratio of
calcium to sodium in a waste plastic feedstock may be from about
0.0001 to 4. In some examples, the mass ratio of calcium to sodium
in a waste plastic feedstock may be from about 0.0001 to 0.04. In
some examples, the mass ratio of calcium to sodium in a waste
plastic feedstock may be from about 0.0001 to 0.04, 0.4, 4, 40, or
400. In some examples, the mass ratio of calcium to sodium in a
waste plastic feedstock may be about 0.00001 to 1000, 0.0001 to
400, or 0.001 to 4. In some examples, the mass ratio of calcium to
sodium in a waste plastic feedstock may be about 0.0001 to 1000,
100, 10, 1, 0.1, 0.01, or 0.001.
In some examples, a residue may contain levels, measurable by
ICP-OES, of the metals calcium and sodium. In some examples, the
mass ratio of calcium to sodium in a residue may be from about
0.0001 to 400. In some examples, the mass ratio of calcium to
sodium in a residue may be from about 0.005 to 280. In some
examples, the mass ratio of calcium to sodium in a residue may be
from about 0.003 to 40. In some examples, the mass ratio of calcium
to sodium in a residue may be from about 0.003 to 4. In some
examples, the mass ratio of calcium to sodium in a residue may be
from about 0.0001 to 0.04. In some examples, the mass ratio of
calcium to sodium in a residue may be from about 0.0001 to 0.04,
0.4, 4, 40, or 400. In some examples, the mass ratio of calcium to
sodium in a residue may be from about 0.0001 to 1000, 100, 10, 1,
0.1, 0.01, or 0.001.
Methods
[0050] The disclosure provides methods to obtain a
hydrocarbonaceous species or mixture of hydrocarbonaceous species
from thermal decomposition of at least one waste plastic feedstock.
At least one metal internal catalyst (e.g., metal that is a
component of a waste plastic feedstock, metal that is a component
of a residue, or metal that is a component of any apparatus used to
execute methods of the disclosure) may serve as a catalytic agent
during a thermal decomposition process. In some situations, no
external catalyst is used. A process flow diagram for an example
method 400 of the disclosure is shown in FIG. 4. In the example
method 400, a waste plastic feedstock 405 may be provided to a
reactor that contains a residue 410 and is sealed. Residue may
already be present, due to its build-up in the reactor over several
cycles of waste plastic feedstock heating. The reactor may be
heated to increasingly higher temperatures throughout a given
reaction time. As heating occurs, the waste plastic feedstock may
be liquefied and thermally decomposed, where internal catalysts may
serve as catalysts. Some lower molecular-weight hydrocarbons that
may be generated during decomposition may volatilize and distill
off the liquefied waste plastic feedstock to form a hydrocarbon
vapor stream 415. The hydrocarbon vapor stream 415, containing at
least one lower molecular-weight hydrocarbon, may then be condensed
in a condenser 420 to a hydrocarbon liquid distillate 425 and may
be either directed to at least one product storage tank 430 for
recovery of the hydrocarbon liquid distillate 425 or, first, may be
directed to one or more downstream separation unit operations 435
to obtain a further refined distillate 440 that may then be
directed to at least one product storage tank 430 for further
use.
[0051] A process flow diagram for another example method 500 of the
disclosure is shown in FIG. 5. In the example method 500, raw waste
plastic 505 may be entered into a waste plastic storage silo 510
that supplies at least one pre-processing unit operation (e.g.,
cleaning unit operation, size reduction unit operation) 515 with
waste plastic feedstock 520. The pre-processed waste plastic
feedstock 525 may then be sent to a feeder 530 that provides waste
plastic feedstock 535 to a reactor 540 that contains residue.
Residue may already be present, due to its build-up in the reactor
over several cycles of waste plastic feedstock heating. The reactor
may be heated to increasingly higher temperatures throughout a
given reaction time. As heating occurs, the waste plastic feedstock
may be liquefied and thermally decomposed, where internal catalysts
may serve as catalysts. Some lower molecular-weight hydrocarbons
that may be generated during decomposition may volatilize and
distill off the liquefied waste plastic feedstock to form a
hydrocarbon vapor stream 545. The vapor stream 545, containing at
least one lower molecular-weight hydrocarbon, may then be condensed
in a condenser 550 to a hydrocarbon liquid distillate 555 and may
be either directed to at least one product storage tank 560 for
recovery of the hydrocarbon liquid distillate 555 or, first, may be
directed to one or more downstream separation unit operations 565
to obtain a further refined distillate 570 that is then directed to
at least one product storage tank 560 for further use.
[0052] The example methods 400 and 500 shown in FIG. 4 and FIG. 5
respectively are examples and may not include method components
necessary for executing a particular method of the disclosure.
Non-limiting examples of such components include method parameters,
materials utilized, consumed, or generated in the method, method
process types, method completion times, arrangement of method
components, and method efficiencies. Such components are further
specified in the paragraphs that follow.
[0053] In some examples, the disclosure provides methods that can
be executed in batch mode. In batch mode, a waste plastic feedstock
bolus (or "batch") may be thermally decomposed, all-at-once, in a
discrete cycle of the process. Additional waste plastic boluses may
be thermally decomposed in non-continuous, separate method
cycles.
[0054] In some examples, the disclosure provides methods that can
be executed in continuous mode. In continuous mode, waste plastic
feedstock may be continuously fed to a reactor and heated, with
continuous generation of lower molecular-weight hydrocarbon vapor
streams, continuous subsequent condensation of the vapor stream
into a liquid distillate, and, optionally, continuous separation
processing of the distillate. Unlike batch mode, continuous
processes generally do not involve discrete method cycles.
[0055] Methods of the disclosure utilize waste plastic feedstocks
to produce valuable, lower molecular-weight hydrocarbons. In some
examples, methods of the disclosure may utilize a waste plastic
feedstock may be comprised of a single type of waste plastic. In
some examples, a waste plastic feedstock may be comprised of a
select assortment of at least two types of waste plastic, in select
ratios or in random ratios. In some examples, a waste plastic
feedstock may be comprised of a random assortment of at least two
types of waste plastic, wherein the types and/or ratios of waste
plastic in the waste plastic feedstock are known or unknown.
[0056] Methods of disclosure may be comprised of one or more
pre-processing methods. Pre-processing methods generally involve
the processing of raw waste plastic and/or a waste plastic
feedstock prior to the entry of a resulting waste plastic feedstock
into a reactor for thermal decomposition. Non-limiting examples of
pre-processing include collection processes (e.g., storage of
plastic materials in a storage vessel), sorting processes (e.g., by
size, by plastic type, by weight, etc.), size reduction processes
(e.g., grinding, shredding, extruding, pulverizing, pelletizing,
granulizing, cutting), cleaning processes (e.g., washing, magnetic
separation),drying processes (e.g., to remove adhered liquids), or
weighing processes (e.g., to weigh materials utilized, generated,
or consumed). Moreover, one or more of the pre-processing methods
mentioned above may be included downstream of a thermal
decomposition process, for post-processing of a material.
[0057] Methods of the disclosure generally involve the
decomposition of a waste plastic feedstock with increasing
temperature. In some examples, the temperature, at any given time,
in a reactor wherein waste plastic feedstock is thermally
decomposed is from about 125.degree. C. to 800.degree. C. In some
examples, the temperature in a reactor, at any given time, is from
about 125.degree. C. to 500.degree. C. In some examples, the
temperature in a reactor, at any given time, is from about
150.degree. C. to 410.degree. C. In some examples, the temperature
in a reactor, at any given time, is from about 125.degree. C. to
375.degree. C. In some examples, the temperature in a reactor, at
any given time, is from about 125.degree. C. to 175.degree. C.,
175.degree. C. to 225.degree. C., 225.degree. C. to 275.degree. C.,
275.degree. C. to 325.degree. C., 325.degree. C. to 375.degree. C.,
375.degree. C. to 425.degree. C., 425.degree. C. to 525.degree. C.,
525.degree. C. to 625.degree. C., or 625.degree. C. to 825.degree.
C. In some examples, the temperature ramp rate, at any given time,
in a reactor wherein waste plastic feedstock is thermally
decomposed is from about 0.1.degree. C./min to 10.degree. C./min.
In some examples, the temperature ramp rate in a reactor wherein
waste plastic feedstock is thermally decomposed is from about
0.1.degree. C./min to 3.degree. C./min. In some examples, the
temperature ramp rate is from about 0.1.degree. C./min to 1.degree.
C./min. In some examples, the temperature ramp rate is from about
0.1.degree. C./min to 0.7.degree. C./min. In some examples, the
temperature ramp rate is from about 0.1.degree. C./min to
0.3.degree. C./min, 0.3.degree. C./min to 0.6.degree. C./min,
0.6.degree. C./min to 0.9.degree. C./min, 0.9.degree. C./min to
1.2.degree. C./min, 1.2.degree. C./min to 1.5.degree. C./min,
1.5.degree. C./min to 1.8.degree. C./min, 1.8.degree. C./min to
2.1.degree. C./min, 2.1.degree. C./min to 2.4.degree. C./min,
2.4.degree. C./min to 2.7.degree. C./min, 2.7.degree. C./min to
3.0.degree. C./min, 3.degree. C./min to 5.degree. C./min, 5.degree.
C./min to 7.degree. C./min, 7.degree. C./min to 9.degree. C./min,
or 9.degree. C./min to 11.degree. C./min. In some examples, an
optimum temperature is determined. In some examples, the optimum
temperature is from about 100.degree. C. to 400.degree. C. In some
examples, the optimum temperature is from about 200.degree. C. to
300.degree. C. In some examples, the optimum temperature is from
about 220.degree. C. to 270.degree. C. In some examples, the
optimum temperature is from about 100.degree. C. to 150.degree. C.,
150.degree. C. to 200.degree. C., 200.degree. C. to 250.degree. C.,
250.degree. C. to 300.degree. C., 300.degree. C. to 350.degree. C.,
or 350.degree. C. to 400.degree. C.
[0058] Methods of the disclosure generally involve the thermal
decomposition of a waste plastic feedstock over time. In some
examples, the reaction time is from about 1 hour to 10 hours. In
some examples, the reaction time is from about 2 hours to 5 hours.
In some examples, the reaction time is from about 3 hours to about
5 hours. In some examples, the reaction time is from about 4 hours
to 5 hours. In some examples, the reaction time is from about 5
hours to 6 hours. In some examples, the reaction time is about
0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75, 2, 2.25, 2.5, 2.75, 3, 3.25,
3.5, 3.75, 4, 4.25, 5, 5.25, 5.5, 5.75, 6, 6.25, 6.5, 6.75, 7,
7.25, 7.5, 7.75, 8, 8.25, 8.5, 8.75, 9, 9.25, 9.5, 9.75, or 10
hours.
[0059] Methods of the disclosure generally involve the production
of at least one lower molecular-weight hydrocarbon from the thermal
decomposition of a waste plastic feedstock in the presence of a
residue generated from one or more previously heated waste plastic
feedstock(s). In some examples, methods of the disclosure may
utilize a weight percent of residue to waste plastic feedstock from
about 5%-200%. In some examples, the weight percent of residue to
waste plastic feedstock is from about 5%-100%. In some examples,
the weight percent of residue to waste plastic feedstock is from
about 5%-20%. In some examples, the weight percent of residue to
waste plastic is about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%,
11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 25%, 30%, 35%,
40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%,
110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, or 200%.
[0060] Methods of the disclosure may include one or more chemical
additives added to the reactor to improve the efficiency of thermal
decomposition of a waste plastic feedstock. Non-limiting examples
of agents that may be used as a chemical additive include calcium
hydroxide, aluminum trioxide, aluminum oxide, sodium hydroxide,
zinc oxide, activated carbon, ferric oxide, ferric carbonate, and
sodium bicarbonate.
[0061] Methods of the disclosure may be comprised of distillation
methods to separate lower molecular-weight hydrocarbons from a
thermally decomposed waste plastic feedstock. In a general
distillation method, one or more component liquid species may be
separated from a liquid mixture based on differing boiling points
of the component liquids in the mixture. Through executing some
methods of the disclosure, a solid waste plastic feedstock is
heated, and portions of the feedstock may be liquefied and
decomposed to form, at least in part, a liquid mixture of lower
molecular-weight hydrocarbons. As the liquid mixture of lower
molecular-weight hydrocarbons is heated with increasing
temperature, the temperature of the liquid mixture may step through
the boiling temperatures of the mixture's lower molecular-weight
hydrocarbon components. When a boiling temperature of a lower
molecular-weight hydrocarbon component is reached, that component
may be vaporized and boil off the mixture. Each component may have
a different boiling point from other components in the mixture and,
thus, separation of the mixture into its component lower
molecular-weight hydrocarbon species may be achieved. As a
component lower molecular-weight hydrocarbon species is distilled
off from the liquid mixture, the lower molecular-weight hydrocarbon
vapor stream that is generated may be directed into a region of
substantially lower temperature wherein the vapor is condensed and
recovered in as a liquid distillate. As a component lower
molecular-weight hydrocarbon species is distilled off from the
liquid mixture, the lower molecular-weight hydrocarbon vapor stream
that is generated may be directed into a region of substantially
lower temperature wherein the vapor is condensed and recovered in
as a liquid distillate, such, as for example, in a condenser. In
some examples, the liquid that was not distilled (sometimes called
the "bottoms" product) is recovered. In some examples, methods of
the disclosure may be comprised of a single stage distillation or
may be comprised of multiple distillation stages. In some examples,
wherein methods of the disclosure are comprised of multiple
distillation stages, multiple distillation stages may be completed
in a single unit operation, for example, a fractional distillation
unit. In some examples, wherein methods of the disclosure are
comprised of multiple distillation stages, multiple distillation
stages may be completed in a series of staged units, such as, for
example, a series of still pots fluidly linked together via one or
more condenser unit operations. In some examples, more specialized
forms of distillation may be useful, with non-limiting examples of
more specialized forms of distillation that include steam
distillation, vacuum distillation, air-sensitive vacuum
distillation, short path distillation, zone distillation,
extractive distillation, or flash distillation. In some examples,
distillation methods may be executed in batch mode or continuous
mode.
[0062] Methods of the disclosure may be comprised of additional
separation methods to separate chemical species, including, for
example, the further refinement of lower molecular-weight
hydrocarbon distillates that are generated. Such methods may be
utilized upstream or downstream of a thermal waste plastic
feedstock process, depending on the particular need. Non-limiting
examples of additional separation methods, in addition to
distillation, that may be included in methods of the disclosure
include evaporation separation methods, absorption separation
methods, adsorption separation methods, liquid-liquid extraction
separation methods, membrane separation methods, filtration
separation methods, and sedimentation separation methods.
[0063] Methods of the disclosure may be comprised of evaporation
separation methods. Evaporation separation methods generally
involve the vaporization of one or more components of a liquid
mixture. Evaporation may occur at ambient temperature or may be
accelerated, for example, with heating. Evaporation methods may be
useful in methods of the disclosure, for example, for concentrating
lower molecular-weight hydrocarbon products that may be obtained
from executing methods of the disclosure or may be useful for
removing relatively volatile components from a liquid mixture.
[0064] Methods of the disclosure may be comprised of absorption
separation methods. In general, absorption separation methods
involve the contacting of a gas with a liquid phase to remove
solutes of either the gas or liquid phase. Absorption separation
methods may be useful in methods of the disclosure, for example,
for capturing desired solutes contained in a gas phase during
separation processes or removing unwanted components from a liquid
phase.
[0065] Methods of the disclosure may be comprised of adsorption
separation methods. In general, adsorption separation methods
involve a solid matrix, in which a gas or liquid stream is flowed
through the matrix and the solid matrix adheres desired components
of the gas or liquid stream. Adsorption unit operations may be
useful in methods of the disclosure, for example, in removing
contaminants from a gas or liquid stream.
[0066] Methods of the disclosure may be comprised of liquid-liquid
extraction separation methods. Liquid-liquid extraction separation
generally involves the contacting of one or more liquids, wherein
mass is transferred from one liquid to another. Liquid-liquid
extraction unit operations may be useful in methods of the
disclosure, for example, in further purifying a liquid stream.
[0067] Methods of the disclosure may be comprised of membrane
separation methods. Membrane unit operations generally involve the
mass transfer of one or more solutes from a liquid or gas phase to
another liquid or gas phase, through a semi-permeable membrane. In
some examples, the membrane permeability of a species may be
controlled, in whole or part, by molecular weight of the species
electric charge of the species, or and/or lipophilicity of the
species. Membrane unit operations may be useful in methods of the
disclosure, for example, in further purifying gas and liquid
streams. Non-limiting examples of membrane separation processes
include dialysis and reverse osmosis.
[0068] Methods of the disclosure may be comprised of filtration
separation methods. Filtration separation methods generally remove
solid species from a liquid mixture by size exclusion. Small holes
in a filter media, for example, may block the passage of larger
solid particles while remaining permeable to a liquid mobile phase
that contains the larger particles. Solid particles that cannot
penetrate the filter media may build-up on the filter media to form
a filter cake. Filtration unit operations may be useful in methods
of the disclosure, for example, for removing solid contaminants of
liquid streams or for removing solid materials from a liquid
mixture, formed from material precipitation during processing.
[0069] Methods of the disclosure may be comprised of sedimentation
separation methods. Sedimentation separation methods generally
involve the removal of solid species from a fluid mixture by
gravity and/or an applied force, such as, for example centrifugal
force or electromagnetic force. Larger particles generally may have
faster settling velocities than smaller particles and the two may
be differentially separated exploiting the differences in settling
velocity. Sedimentation unit operations may be useful in systems of
the disclosure, for example, for removing solid contaminants of
purified liquid or gas streams or for removing solid materials
formed from material precipitation during material processing.
[0070] Mass conversion achieved from executing methods of the
disclosure may vary depending on the specific reaction parameters
used. In some examples, the reactor contains residue built-up from
prior heating of one or more waste plastic feedstocks. Conversion
rates may be lower in reactors where build up has only recently
commenced, when compared to reactors that contain significant
residue build-up. Such differences in conversion rates may be due
to the lower levels of catalytic metals present in lower levels of
residue. In some examples, the mass conversion achieved is from
about 0% to 100%. In some examples, the mass conversion achieved is
from about 50% to 100%. In some examples, the mass conversion
achieved is from about 70% to 85%. In some examples, the mass
conversion achieved is from about 65% to 97%. In some examples, the
mass conversion achieved is about 0%, 1%, 5%, 10%, 15%, 20%, 25%,
30%, 35%, 40%, 45%, 50%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%,
68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%,
81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%,
94%, 95%, 96%, 97%, 98%, 99%, or 100%.
[0071] Lower molecular-weight hydrocarbons may be produced by
methods of the disclosure. In some examples, hydrocarbons may be
produced that possess carbon-chain lengths from about C.sub.1 to
C.sub.30. In some examples, hydrocarbons may be produced that
possess carbon-chain lengths from about C.sub.5 to C.sub.15. In
some examples, hydrocarbons may be produced that possess
carbon-chain lengths from about C.sub.15 to C.sub.28. In some
examples, lower molecular-weight hydrocarbons that may be produced
by methods of the disclosure may include liquid-phase species or
gas-phase species. Gas-phase species may be very low carbon-chain
length hydrocarbons that cannot be condensed at ambient conditions.
Non-limiting examples of lower molecular-weight hydrocarbons
produced by methods of the disclosure include alcohols (e.g.,
methanol, ethanol, propanols, butanols, pentanols, hexanols,
heptanols, octanols, nonanols, decanols, undecanols, dodecanols,
tridecanols, tetradecanols, pentadecanols, hexadecanols,
heptadecanols, octadecanols, nonadecanols, eicosanols,
heneicosanols, docosanols, tricosanols, pentacosanols,
hexacosanols, octacosanols, tetracosanols, heptacosanols,
nonacosanols, triacontanols), aldehydes (e.g., formaldehyde,
acetaldehyde, propanals, butanals, pentanals, hexanals, heptanals,
octanals, nonanals, decanals, undecanals, dodecanals, tridecanals,
tetradecanals, pentadecanals, hexadecanals, heptadecanals,
octadecanals, nonadecanals, eicosanals, heneicosanals, docosanals,
tricosanals, pentacosanals, hexacosanals, octacosanals,
tetracosanals, heptacosanals, nonacosanals, triacontanals), ketones
(e.g., acetone, butanones, pentanones, hexanones, heptanones,
octanones, nonanones, decanones, undecanones, dodecanones,
tridecanones, tetradecanones, pentadecanones, hexadecanones,
heptadecanones, octadecanones, nonadecanones, eicosanones,
heneicosanones, docosanones, tricosanones, pentacosanones,
hexacosanones, octacosanones, tetracosanones, heptacosanones,
nonacosanones, triacontanones), alkanes (e.g., methane, ethane,
propanes, butanes, pentanes, hexanes, heptanes, octanes, nonanes,
decanes, undecanes, dodecanes, tridecanes, tetradecanes,
pentadecanes, hexadecanes, heptadecanes, octadecanes, nonadecanes,
eicosanes, heneicosanes, docosanes, tricosanes, pentacosanes,
hexacosanes, octacosanes, tetracosanes, heptacosanes, nonacosanes,
triacontanes), alkenes (e.g., methene, ethene, propenes, butenes,
pentenes, hexenes, heptenes, octenes, nonenes, decenes, undecenes,
dodecenes, tridecenes, tetradecenes, pentadecenes, hexadecenes,
heptadecenes, octadecenes, nonadecenes, eicosenes, heneicosenes,
docosenes, tricosenes, pentacosenes, hexacosenes, octacosenes,
tetracosenes, heptacosenes, nonacosenes, triacontenes), alkynes
(e.g., methyne, ethyne, propynes, butynes, pentynes, hexynes,
heptynes, octynes, nonynes, decynes, undecynes, dodecynes,
tridecynes, tetradecynes, pentadecynes, hexadecynes, heptadecynes,
octadecynes, nonadecynes, eicosynes, heneicosynes, docosynes,
tricosynes, pentacosynes, hexacosynes, octacosynes, tetracosynes,
heptacosynes, nonacosynes, triacontynes), and carboxylic acids
(e.g., formic acid, acetic acid, propanoic acids, butanoic acids,
pentanoic acids, hexanoic acids, heptanoic acids, octanoic acids,
nonanoic acids, decanoic acids, undecanoic acids, dodecanoic acids,
tridecanoic acids, tetradecanoic acids, pentadecanoic acids,
hexadecanoic acids, heptadecanoic acids, octadecanoic acids,
nonadecanoic acids, eicosanoic acids, heneicosanoic acids,
docosanoic acids, tricosanoic acids, pentacosanoic acids,
hexacosanoic acids, octacosanoic acids, tetracosanoic acids,
heptacosanoic acids, nonacosanoic acids, triacontanoic acids).
[0072] In some examples, lower molecular-weight hydrocarbons that
may be produced by methods of the disclosure may be useful as fuels
with non-limiting examples that include automobile fuel, passenger
and commercial truck fuel, heating fuel, aircraft fuel,
small-engine fuel, f generators, train fuel, industrial equipment
fuels, chemical processing equipment fuels, and ship fuel.
Systems
[0073] The disclosure also provides systems that may be utilized to
execute methods of the disclosure that convert a waste plastic
feedstock to lower molecular-weight hydrocarbon materials. In some
examples, systems of the disclosure may be capable of operating in
batch mode. In some examples, systems of the disclosure may be
capable of operating in continuous mode, or in either batch mode or
continuous mode. An example system 600 that can operate in batch
mode is shown in FIG. 6. In the example system 600, a waste plastic
feedstock bolus 605 can be provided all-at-once, through a closable
port 610, to a reactor 615 that contains residue from a previously
heated waste plastic feedstock. Port 610 can then be closed for
heating of reactor 615. Reactor 615 may be a glass, flask-style
reactor and may be in thermal and mechanical contact with an
external electrical heater 620. With port 610 closed, the waste
plastic feedstock bolus 605 can be heated and liquefied to generate
a vapor stream 625 of lower molecular-weight hydrocarbons. The
reactor 615 may be fluidly connected, via a glass connector 630
that may serve as a transport route for vapor stream 625, to a
condenser unit 635 that condenses vapor stream 625 to a liquid
distillate 640. The condenser 635 may be circumscribed with a
cooling jacket 645. Cooling water may enter the jacket at inlet
650, and may be capable of reducing the temperature inside
condenser 635, and may exit the jacket at outlet 655. The condenser
635 may be angled such that gravity can transport, via fluidly
connected glass connector 660, the liquid distillate 640 from the
condenser 635 into a glass, distillate recovery flask 665. The
final product 670 may be removed from the glass, distillate
recovery flask 665, via closable port 675.
[0074] An example system 700 that can be operated in continuous or
batch mode is shown in FIG. 7. In example system 700, a waste
plastic feedstock storage silo 701 stores waste plastic feedstock.
A gate 702 connected to waste plastic feedstock storage silo 701
may be used to release waste plastic feedstock from the waste
plastic feedstock storage silo 701 into a primary grinder 703.
Primary grinder 703 can reduce the size of the waste plastic
feedstock obtained from waste plastic feedstock storage silo 701.
The ground waste plastic feedstock may then be deposited from
primary grinder 703, via gravity, onto a conveyor belt 704 arranged
to transport the ground waste plastic feedstock into secondary
grinder 705. Secondary grinder 705 can further reduce the size of
the ground waste plastic feedstock received from conveyor belt 704.
The double-ground waste plastic feedstock may then be deposited
from secondary grinder 705, onto conveyor belt 706, arranged to
transport the double-ground waste plastic feedstock into batch
chute 707. As the double-ground waste plastic feedstock is
transported by conveyor belt 706 to batch chute 707, the
double-ground waste plastic feedstock is exposed to a magnetic
separator 708 that can remove unwanted magnetic materials from the
double-ground waste plastic feedstock. A gate 709 connected to
batch chute 707 may be used to release, via gravity, double-ground
waste plastic feedstock into reactor 710. Reactor 710 may be a
jacketed, stainless-steel vessel that may be equipped with an
agitator 711 that may be used to stir the contents of reactor 710.
Reactor 710 may be equipped with temperature and pressure sensors
necessary to communicate with control systems, a pressure relief
valve, and may be heated with a heat transfer fluid that is
circulated through the equipped jacket. The heat transfer fluid may
be provided by a heat transfer fluid tank 712 that may be equipped
with a pump 713 that can regulate the flow of heat transfer fluid,
via piping 714, into the jacket of reactor 710. Heat transfer fluid
tank 712 includes a heat-exchanger that heats the heat transfer
fluid prior to its circulation in the jacket of reactor 710.
Chemical additive storage tanks 715 and 716 can each provide an
optional chemical additive, via piping 717 and 718 respectively, to
reactor 710. Reactor 710 may be fluidly connected, via piping 719
to a condenser 720. Piping 719 may be capable of receiving lower
molecular-weight vapor streams generated from thermal decomposition
of waste plastic feedstocks in reactor 710 and directing the vapor
streams into condenser 720. Condenser 720 can receive the vapor
streams via piping 719 and condense the vapor streams to produce a
liquid distillate. Chilled cooling water can be circulated through
the condenser 720 to reduce temperatures inside condenser 720 to
values required for proper vapor stream condensation. Chilled water
may be provided by water chiller 721, via piping 722, to condenser
720. After its use in condenser 720, spent chilled water can be
recycled, via piping 723, back to water chiller 721. The liquid
distillate that is recovered by condenser 720, may be transported,
via piping 724, into product storage tank 725. Product 726 can be
transported to downstream processes for further use via piping 727,
which may be controlled by control valve 728.
[0075] In an example of batch mode operation, system 700 may be
operated such that a bolus of waste plastic feedstock is provided
from waste plastic feedstock storage silo 701 by gate 702, and the
bolus pre-processed using primary grinder 703 and secondary grinder
705. The double-ground waste plastic feedstock is transported, via
conveyor belt 706, to batch chute 707, where it is further stored.
A bolus of double-ground waste plastic (either all of, or a portion
of, the double-ground waste plastic feedstock supplied to batch
chute 707) is then supplied, possibly at a later time, via gate
709, to reactor 710 for its thermal decomposition. Vapor streams
that may be generated in reactor 710 may be directed further
downstream for condensation in condenser 720 and collection of the
liquid distillate in storage tank 725.
[0076] In an example of continuous mode operation, system 700 may
be operated such that waste plastic feedstock stored in waste
plastic feedstock storage silo 701 may be released continuously by
gate 702, for continuous pre-processing in primary 703 and
secondary 704 grinders. Double-ground waste plastic feedstock may
then be continuously added, via conveyor belt 706, into batch chute
707, where it may or may not be accumulated. Gate 709 may
continuously supply double-ground waste plastic feedstock from
batch chute 707 into reactor 710 for its continuous heating and
thermal decomposition. Vapor streams may be generated from reactor
710 continuously and, thus, may be continuously routed downstream
for condensation in condenser 720 and collection of the liquid
distillate in storage tank 725.
[0077] The example systems 600 and 700 shown in FIG. 6 and FIG. 7
are examples and may not include components necessary for executing
a particular method of the disclosure. Various combinations of unit
operations, material storage vessels, material transport equipment,
sensors, control systems, and equipment (e.g., control valves,
heaters, etc.) that may be used to exercise control over a system.
Various, non-limiting examples of components that may be included
in systems of the disclosure and the arrangement of such components
are outlined in the paragraphs that follow.
[0078] Systems of the disclosure may include one or more plastic
storage vessels capable of storing and serving as, for example, a
source of raw waste plastic or a waste plastic feedstock. Plastic
storage vessels may be capable of being held at ambient temperature
or may be capable of being temperature controlled to prevent
volatilization of the contained materials. Plastic storage vessels
may be capable of being held at atmospheric pressure or may be
capable of being pressurized in order to maximize the holding
capacity of the contained materials. Non-limiting examples of
vessels that may be utilized as plastic storage vessels include
silos, tanks, flasks, stills, pots, kettles, and beakers.
[0079] Systems of the disclosure may include one or more sorting
unit operations to sort raw waste plastics or waste plastic
feedstocks for their use in a waste plastic feedstock of desired
composition. Non-limiting examples of sorting capabilities of a
sorting unit operation include the capability to sort by material
size (e.g., length, width, or thickness), material color, plastic
type, or weight. In some examples, systems of the disclosure may
contain one or more sorting unit operations that are consecutively
staged or discontinuously staged. In some examples, systems of the
disclosure may contain one or more sorting unit operations that are
staged in parallel. In some examples, a sorting unit operation may
be capable of being operated in batch mode or continuous mode.
[0080] Systems of the disclosure may include one or more size
reduction unit operations. Such unit operations may receive larger
pieces of raw waste plastic and/or waste plastic feedstock and may
be capable of reducing the size of large pieces. Non-limiting
examples of unit operations that can reduce the size of raw waste
plastic and/or waste plastic feedstock include grinders (e.g.,
hammer mill grinders, revolving grinding mills), crushers (e.g.,
jaw crushers, Blake crushers, gyratory crushers, roll crushers),
shredders, cutting unit operations, tearing unit operations,
granulators, and pelletizers. In some examples, systems of the
disclosure may contain one or more size reduction unit operations
that are consecutively staged or discontinuously staged. In some
examples, systems of the disclosure may contain one or more size
reduction unit operations that are staged in parallel. In some
examples, a size reduction unit operation may be capable of being
operated in batch mode or continuous mode.
[0081] Systems of the disclosure may include one or more waste
plastic cleaning unit operations. Such unit operations may be
capable of removing some contaminants (e.g., dirt, unwanted
materials that have adhered to plastic surfaces) from raw waste
plastic and/or waste plastic feedstock, and/or remove additives
(e.g., colorants, adhesive labels, other structural support
materials) utilized during manufacturing of raw waste plastic. In
one example, a plastic cleaning unit operation may be a common
household dishwasher. In some examples, a magnetic separator unit
operation may be utilized and may be capable of removing undesired
materials from raw waste plastic or waste plastic feedstock that
may be magnetically responsive. In some examples, systems of the
disclosure may contain one or more waste plastic cleaning or
magnetic separator unit operations that are consecutively staged or
discontinuously staged. In some examples, systems of the disclosure
may contain one or more waste plastic cleaning or magnetic
separator unit operations that are staged in parallel. In some
examples, a waste plastic cleaning or magnetic separator unit
operation may be capable of being operated in batch mode or
continuous mode.
[0082] Systems of the disclosure may include one or more drying
unit operations used to dry raw waste plastic and/or waste plastic
feedstock. Such units may be capable of removing unwanted moisture
from raw waste plastic or waste plastic feedstock. Such moisture
may, for example, have been generated during a cleaning process or
from atmospheric moisture that has condensed onto plastic surfaces.
Non-limiting examples of drying unit operations that may be
included in systems of the disclosure include tray dryers,
vacuum-shelf indirect dryers, continuous tunnel dryers, rotary
dryers, drum dryers, or spray dryers. In some examples, systems of
the disclosure may contain one or more drying unit operations that
are consecutively staged or discontinuously staged. In some
examples, systems of the disclosure may contain one or more drying
unit operations that are staged in parallel. In some examples, a
drying unit operation may be capable of being operated in batch
mode or continuous mode.
[0083] Systems of the disclosure may include one or more unit
operations that are capable of weighing any material component
consumed or generated by methods of the disclosure. Non-limiting
examples of species that such unit operations may be capable of
weighing include raw waste plastic, waste plastic feedstock,
residue from a previously heated waste plastic feedstock, residue
generated from a waste plastic currently being heated, vapor
containing lower molecular-weight hydrocarbons distilled from
decomposed waste plastic feedstock, liquid distillate recovered
after condensation of a vapor containing lower molecular-weight
hydrocarbons, or any product obtained from further
refinement/separation of the recovered liquid distillate. Weighing
units may be useful for a number of purposes with non-limiting
examples that include determining correct reactant ratios, correct
material supply levels, and reaction mass conversion. Unit
operations used for weighing may be separate from other unit
operations (e.g., a separate scale) or may comprise a larger unit
operation. In one example, a plastic storage vessel may be
comprised of a unit operation to weigh a waste plastic feedstock
contained in the vessel. In some examples, systems of the
disclosure may contain one or more weighing unit operations that
are consecutively staged or discontinuously staged. In some
examples, systems of the disclosure may contain one or more
weighing unit operations that are staged in parallel. In some
examples, a weighing unit operation may be capable of being
operated in batch mode or continuous mode.
[0084] Systems of the disclosure may include one or more feeder
unit operations. A feeder may be capable of molding a waste plastic
feedstock into a size and shape appropriate for use inside a
reactor and/or to transport waste plastic feedstock into a reactor.
Non-limiting examples of a feeder unit operation that may included
in systems of the disclosure include an extruder or batch chute. In
some examples, systems of the disclosure may contain one or more
feeder unit operations that are consecutively staged or
discontinuously staged. In some examples, systems of the disclosure
may contain one or more feeder unit operations that are staged in
parallel. In some examples, a feeder unit operation may be capable
of being operated in batch mode or continuous mode.
[0085] Systems of the disclosure rely on at least one reactor that
may be used for thermal decomposition of a waste plastic feedstock
into lower molecular-weight hydrocarbons. Non-limiting examples of
vessels that may be used as reactors in systems of the disclosure
include batch reactors, continuous-stir tank reactors, flow
reactors, packed bed reactors, membrane reactors, flasks, stills,
pots, fractional distillation columns, kettles, tanks, and beakers.
Such reactors may or may not be comprised of at least one agitator
that may be used to stir a heated reactor's contents. In some
examples, a reactor may be capable of being operated in batch mode
or continuous mode. In some examples, systems of the disclosure may
include multiple reactors. Such reactors may be arranged in series,
may be arranged in parallel, or may be arranged discontinuously.
Reactors may also contain a residue generated from a previously
heated waste plastic feedstock. As mentioned previously, residue in
reactors may have been build-up in a reactor over repeated cycles
of waste plastic feedstock heating and may contain metal agents
capable of catalytic activity in the thermal decomposition of a
waste plastic feedstock. In some examples, a residue may be adhered
to an inner surface of a reactor used to heat a waste plastic
feedstock or may be free from an inner surface of a reactor used to
heat a waste plastic feedstock. In some examples, a reactor may
contain both free and adhered residue.
[0086] In some instances, reactors used in systems of the
disclosure may include residues that may be comprised, in whole or
part, of metals. Such metals may be capable of acting as internal
catalysts during thermal decomposition of a waste plastic
feedstock. Non-limiting examples of metals that may be a component
of residues that may be found in reactors include aluminum,
antimony, arsenic, barium, beryllium, bismuth, boron, cadmium,
calcium, cesium, chromium, cobalt, copper, gallium, germanium,
gold, hafnium, indium, iron, lead, lithium, magnesium, manganese,
mercury, molybdenum, nickel, platinum, palladium, potassium,
rhodium, iridium, osmium, ruthenium, rhenium, rubidium, scandium,
selenium, silicon, silver, sodium, strontium, tantalum, tellurium,
thallium, thorium, tin, titanium, tungsten, vanadium, zinc, and
zirconium.
[0087] In some instances, residues that may be contained in a
reactor may be comprised of all of following elements: aluminum,
antimony, arsenic, barium, beryllium, bismuth, boron, cadmium,
calcium, cesium, chromium, cobalt, copper, gallium, germanium,
gold, hafnium, indium, iron, lead, lithium, magnesium, manganese,
mercury, molybdenum, nickel, platinum, palladium, potassium,
rhodium, iridium, osmium, ruthenium, rhenium, rubidium, scandium,
selenium, silicon, silver, sodium, strontium, tantalum, tellurium,
thallium, thorium, tin, titanium, tungsten, vanadium, zinc, and
zirconium. In some examples, residues that may be contained in a
reactor may be comprised of at least one of the above elements. In
some examples, residues that may be contained in a reactor may be
comprised of at least two of the above elements. In some examples,
residues that may be contained in a reactor may be comprised of at
least three of the above elements. In some examples, residues that
may be contained in a reactor may be comprised of at least four of
the above elements. In some examples, residues that may be
contained in a reactor may be comprised of at least five of the
above elements. In some examples, residues that may be contained in
a reactor may be comprised of 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32,
33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49,
or 50 of the above elements. In some examples, residues that may be
contained in a reactor may be comprised of at least 1, 2, 3, 4, 5,
6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 of following elements:
aluminum, antimony, arsenic, barium, beryllium, bismuth, boron,
cadmium, calcium, cesium, chromium, cobalt, copper, gallium,
germanium, gold, hafnium, indium, iron, lead, lithium, magnesium,
manganese, mercury, molybdenum, nickel, platinum, palladium,
potassium, rhodium, iridium, osmium, ruthenium, rhenium, rubidium,
scandium, selenium, silicon, silver, sodium, strontium, tantalum,
tellurium, thallium, thorium, tin, titanium, tungsten, vanadium,
zinc, and zirconium.
[0088] In some examples, residues that may be contained in a
reactor may contain levels, measurable by ICP-OES, of the metals
calcium and sodium. In some examples, the mass ratio of calcium to
sodium in residues that may be contained in a reactor may be from
about 0.0001 to 400. In some examples, the mass ratio of calcium to
sodium in residues that may be contained in a reactor may be from
about 0.005 to 280. In some examples, the mass ratio of calcium to
sodium in residues that may be contained in a reactor may be from
about 0.003 to 40. In some examples, the mass ratio of calcium to
sodium in residues that may be contained in a reactor may be from
about 0.003 to 4. In some examples, the mass ratio of calcium to
sodium in residues that may be contained in a reactor may be from
about 0.0001 to 0.04. In some examples, the mass ratio of calcium
to sodium in residues that may be contained in a reactor may be
from about 0.0001 to 0.04, 0.4, 4, 40, or 400. In some examples,
the mass ratio of calcium to sodium in residues that may be
contained in a reactor may be from about 0.0001 to 1000, 100, 10,
1, 0.1, 0.01, or 0.001.
[0089] Systems of the disclosure are generally comprised of one or
more condenser unit operations (also "units" herein) that may be
useful in condensing vapor streams into a liquid condensate. In
some examples, a condenser unit operation may be a surface
condenser, wherein a cooling fluid is used to cool a vapor stream
but is not in contact with the vapor being cooled or the liquid
condensate that is formed. In some examples, a condenser unit
operation may be a direct-contact condenser, in which cooling fluid
directly contacts the vapor being cooled and/or the liquid
condensate that is formed. In some examples, systems of the
disclosure may contain one or more condensers that are
consecutively staged or discontinuously staged. In some examples,
systems of the disclosure may contain one or more condensers that
are staged in parallel. In some examples, a condenser may be
capable of being operated in batch mode or continuous mode.
[0090] Systems of the disclosure may include one or more separation
units. In some examples, such unit operations may arranged upstream
or downstream from a reactor or condenser. Non-limiting examples of
separation unit operations that may be included in systems of the
disclosure include evaporation unit operations, absorption unit
operations, distillation unit operations, adsorption unit
operations, liquid-liquid extraction unit operations, membrane unit
operations, filtration unit operations, and sedimentation unit
operations.
[0091] In an example, a system includes a reactor for generating a
vapor stream comprising one or more hydrocarbons. The vapor stream
is directed into a distillation column that effects the separation
of hydrocarbons into fluid stream. Individual fluid streams may be
directed to additional separation units, such as additional
distillation columns for further separation, as may be
necessary.
[0092] Systems of the disclosure may include at least one
separation unit operation that is an evaporation unit operation. In
general, an evaporation unit may be capable of executing
evaporation separation methods that may be useful, for example, for
concentrating lower molecular-weight hydrocarbon products that may
be obtained from executing methods of the disclosure or may be
useful for removing relatively volatile components from a liquid
mixture. Non-limiting examples of evaporation unit operations that
may be included in systems of the disclosure include open kettles,
open pans, horizontal-tube natural circulation evaporators,
vertical-type natural circulation evaporators, long-tube
vertical-type evaporators, falling-film type evaporators,
forced-circulation type evaporators, agitated-file evaporators,
open-pan solar evaporators, mechanical vapor recompression
evaporators, and thermal vapor recompression evaporators. In some
examples, an evaporator unit operation may be comprised of a single
effect (i.e., a single-stage) or may be comprised of multiple
effects (i.e., multiple-stages). In some examples, effects in a
multiple-effect evaporator may be arranged in series. In some
examples of a multiple-effect evaporator where effects may be
arranged in series, a multiple-effect evaporator may be a
forward-feed multiple-effect evaporator or a backward-feed
multiple-effect evaporator. In some examples, effects in a
multiple-effect evaporator may be arranged in parallel. In some
examples, systems of the disclosure may contain one or more
evaporator unit operations that are consecutively staged or
discontinuously staged. In some examples, systems of the disclosure
may contain one or more evaporator unit operations that are staged
in parallel. In some examples, an evaporator unit operation may be
arranged upstream or downstream from a reactor or condenser. In
some examples, an evaporator unit operation may be capable of being
operated in batch mode or continuous mode.
[0093] Systems of the disclosure may include at least one
separation unit operation that is an absorption unit operation. In
general, an absorption unit operation may be capable of executing
absorption separation methods that may be useful, for example, for
capturing desired solutes contained in a gas phase during
separation processes or removing unwanted components from a liquid
phase containing valuable lower molecular-weight hydrocarbons. In
some examples, a system may utilize a gas phase or liquid phase
that may be comprised of a single chemical component or may be a
gas phase or liquid phase that may be a mixture of two or more
chemical components. In some examples, a gas phase and liquid phase
may be contacted in co-current flow or counter-current flow. In
some examples, separations may be achieved in a single stage or
multiple stages. Non-limiting examples of absorption unit
operations that may be included in systems of the disclosure
include a scrubber, stripper, tray towers, and packed towers. In
some examples, an absorption unit operation may be a tray tower,
wherein the trays used may be sieve trays, valve trays, or
bubble-cap trays. In some examples, an absorption unit operation
may be a packed tower, wherein the packing may be a Raschig ring,
Lessing ring, Berl saddle, or Pall ring. In some examples, an
absorption unit operation may be a packed tower, wherein the
packing may be arranged randomly or in stacked arrangements inside
the packed tower. In some examples, systems of the disclosure may
contain one or more absorption unit operations that are
consecutively staged or discontinuously staged. In some examples,
systems of the disclosure may contain one or more absorption unit
operations that are staged in parallel. In some examples, an
absorption unit operation may be arranged upstream or downstream
from a reactor or condenser. In some examples, an absorption unit
operation may be capable of being operated in batch mode or
continuous mode.
[0094] Systems of the disclosure may include at least one
separation unit operation that is a distillation unit operation. In
general, a distillation unit operation may be capable of executing
distillation separation methods. As mentioned previously,
distillation unit operations may be useful, for example, in
separating component liquids from a liquid mixture, such as lower
molecular-weight hydrocarbons that are generated from the thermal
decomposition of a waste plastic feedstock. In some examples, a
single stage distillation may be all that is needed to achieve a
desired separation or multiple stages may be needed. Non-limiting
examples of vessels used for a single-stage distillation unit
operation include kettles, pots, stills, beakers, flasks, or tanks
In some examples, multiple stages of distillation may be completed
in a single unit such as, for example, a fractional distillation
tower. In some examples, stages in a fractional distillation column
that is included in a system of the disclosure may be trays with
non-limiting examples of trays that include sieve trays, valve
trays, and bubble-cap trays. In some examples, a fractional
distillation tower may also include one or more condenser units,
wherein such condenser units may be arranged to route liquid
distillate downstream to additional unit operations or arranged to
route liquid distillate back into the fractional distillation tower
for additional separation. In some examples, a fractional
distillation unit may also include one or more reboiler units. In
some examples, such reboiler units may be arranged to vaporize
liquid that is removed from the fractional distillation tower,
wherein the vapor can be directed downstream for further use or
processing or can be directed back into the fractional distillation
tower for further separation. In some examples, multiple cycles of
distillation may be completed in staged units, such as, for
example, a series of still pots fluidly linked together via one or
more condenser unit operations. In some examples, a desired product
or products may be recoverable from vapor streams generated during
distillation and/or may be recovered from the liquid that remains
in the distillation unit operation at the conclusion of
distillation. In some examples, systems of the disclosure may be
capable of more specialized forms of distillation with non-limiting
examples of more specialized forms of distillation that include
steam distillation, vacuum distillation, air-sensitive vacuum
distillation, short path distillation, zone distillation,
extractive distillation, or flash distillation. In some examples,
systems of the disclosure may contain one or more distillation unit
operations that are consecutively staged or discontinuously staged.
In some examples, systems of the disclosure may contain one or more
distillation unit operations that are staged in parallel. In some
examples, a distillation unit operation may be arranged upstream or
downstream from a reactor or condenser. In some examples, a
distillation unit operation may be capable of being operated in
batch mode or continuous mode.
[0095] Systems of the disclosure may include at least one
separation unit operation (also "separation unit" herein) that is
an adsorption unit operation. In general, an adsorption unit
operation may be capable of executing adsorption separation methods
that may be useful, for example, in removing contaminants from
liquid stream, such as a liquid distillate generated from
condensing a vapor stream containing valuable lower
molecular-weight hydrocarbons. In some examples, the pore surface
area of a solid matrix contained within an adsorption unit
operation may be from about 100 m.sup.2/g to 2000 m.sup.2/g, from
about 300 m.sup.2/g to 1200 m.sup.2/g, from about 200 m.sup.2/g to
500 m.sup.2/g, or from about 600 m.sup.2/g to 800 m.sup.2/g. In
some examples, the solid matrix material may be comprised of
activated carbon, silica gel, activated alumina, molecular sieve
zeolites, or a synthetic polymer or resin with non-limiting
examples that include styrene, divinylbenzene, or acrylic esters.
In some examples, the solid matrix material may be capable of
adsorbing a species via non-ionic interactions (e.g., Van der Waals
forces) and/or via ionic interactions. In some examples, an
adsorption unit operation may be arranged as a fixed-bed, wherein
the solid matrix material may be stationary or not stationary. In
some examples, the adsorption unit may be arranged as an
ion-exchange column. In some examples, systems of the disclosure
may contain one or more adsorption unit operations that are
consecutively staged or discontinuously staged. In some examples,
systems of the disclosure may contain one or more adsorption unit
operations that are staged in parallel. In some examples, an
adsorption unit operation may be arranged upstream or downstream
from a reactor or condenser. In some examples, an adsorption unit
operation may be capable of being operated in batch mode or
continuous mode.
[0096] Systems of the disclosure may include at least one
separation unit operation that is a liquid-liquid extraction unit
operation. In general, liquid-liquid extraction unit operations are
capable of executing liquid-liquid extraction separation methods
that may be useful in methods of the disclosure, for example, in
further purifying a liquid stream, such as one that contains
valuable lower molecular-weight hydrocarbons. In some examples, one
or more of the liquids used is an organic solvent. A liquid-liquid
extraction unit operation may be arranged as a mixer-settler
apparatus, a plate and agitated tower contractor, a packed spray
tower, or a spray extraction tower. In some examples, systems of
the disclosure may contain one or more liquid-liquid extraction
unit operations that are consecutively staged or discontinuously
staged. In some examples, systems of the disclosure may contain one
or more liquid-liquid extraction unit operations that are staged in
parallel. In some examples, a liquid-liquid extraction unit
operation may be arranged upstream or downstream from a reactor or
condenser. In some examples, a liquid-liquid extraction unit
operation may be capable of being operated in batch mode or
continuous mode. In some examples, two or more liquids may be
contacted via flow, wherein the liquids may be arranged in the
liquid-liquid extraction unit to flow co-current to each other or
counter-current to each other.
[0097] Systems of the disclosure may include at least one
separation unit operation that is a membrane unit operation. In
general, a membrane unit operation may be capable of executing
membrane separation methods. In some examples, a membrane in a
membrane unit operation may be comprised of, in whole or part, a
porous polymer or a microporous solid. In some examples, a membrane
may be comprised of, in whole or part, silicone rubber,
polysulfone, cellulose acetate, aromatic polyamides, aromatic
polyimides, and silicone-polycarbonate co-polymer. In some
examples, a membrane unit operation may be arranged to separate out
components from a gas. In some examples, a membrane unit operation
may be arranged as a dialysis unit, wherein components may be
removed from a liquid using a membrane. In some examples, wherein a
membrane unit operation functions as a dialysis unit, a membrane
may consist of one or more semi-permeable hollow-fibers. In some
examples, a membrane unit operation may be arranged as a reverse
osmosis unit, ultrafiltration unit, or as a gel permeation
chromatography unit. In some examples, active mechanisms, such as,
for example, force supplied by a pump may be used to transport mass
across a membrane or passive mechanisms, such as, for example,
concentration gradients may be used. In some examples, systems of
the disclosure may contain one or more membrane unit operations
that are consecutively staged or discontinuously staged. In some
examples, systems of the disclosure may contain one or more
membrane unit operations that are staged in parallel. In some
examples, a membrane unit operation may be arranged upstream or
downstream from a reactor or condenser. In some examples, a
membrane unit operation may be capable of being operated in batch
mode or continuous mode. In some examples, two or more fluids may
be in mechanical contact with a membrane via flow, wherein the
fluids are arranged to flow co-current to each other,
counter-current to each other, or cross-current to each other.
[0098] Systems of the disclosure may include at least one
separation unit operation that is a filtration unit operation. In
general, a filtration unit operation may be capable of executing
filtration separation methods that may be useful, for example, in
filtering a waste plastic feedstock before the feedstock is
directed to a reactor. In some examples, the filter media that is
included in a filtration unit operation is comprised of cloth or a
screen. In some examples, the filter media that is included in a
filtration unit operation is comprised of twill cloth, duckweave
heavy cloth, woolen cloth, glass cloth paper, felted pads of
cellulose, metal cloth, nylon cloth, Darcon cloth, other synthetic
cloths, and other heavy woven cloths. In some examples, a filter
aid may be utilized as a filter media pre-coat or may be added to a
liquid to be filtered in order to improve porosity of the resulting
solid material cake that forms on the filter media. In some
examples, a filter aid may be comprised of incompressible
diatomaceous earth, kieselguhr, silica, wood cellulose, asbestos,
or other inert porous solids. In some examples, a filtration unit
operation may be arranged as a bed filter. In some examples, a
filtration unit operation may be arranged as a plate-and-frame
press filter, leaf filter, continuous rotary vacuum-drum filter, a
continuous rotary disk filter, or a continuous rotary horizontal
filter. In some examples, active mechanisms, such as, for example,
force provided by a pump or centrifugation may be used to transport
a liquid through a filter media that is included in a filtration
unit operation or passive mechanisms, such as, for example, gravity
may be used. In some examples, a filter cake that forms during
filtration may contain materials that may be useful in other
components of a system or may be useful as materials in other
processes. In some examples, systems of the disclosure may contain
one or more filtration unit operations that are consecutively
staged or discontinuously staged. In some examples, systems of the
disclosure may contain one or more filtration unit operations that
are staged in parallel. In some examples, a filtration unit
operation may be arranged upstream or downstream from a reactor or
condenser. In some examples, a filtration unit operation may be
capable of being operated in batch mode or continuous mode.
[0099] Systems of the disclosure may include at least one
separation unit operation that is a sedimentation unit operation.
In general, a sedimentation unit operation may be capable of
executing sedimentation separation methods that may be useful, for
example, for removing solid contaminants of liquid or gas streams
or for removing solid materials formed from material precipitation
during material processing. In some examples, a sedimentation unit
operation may be arranged to separate solids from a gas or separate
solids from a liquid. In some examples, a sedimentation unit
operation may be arranged as a single settling vessel with
non-limiting examples that include tanks, flasks, stills, pots,
kettles, and beakers. In some examples, a settling unit operation
may be arranged to have one or more receptacles designed to sort
solid materials that may be sedimented. In some examples, a
sedimentation unit operation may be arranged as a Spitzkasten
classifier, a sedimentation thickener, a centrifugal sedimentation
unit, or a gas-solid cyclone unit. In some examples, systems of the
disclosure may contain one or more sedimentation unit operations
that are consecutively staged or discontinuously staged. In some
examples, systems of the disclosure may contain one or more
sedimentation unit operations that are staged in parallel. In some
examples, a sedimentation unit operation may be arranged upstream
or downstream from a reactor or condenser. In some examples, a
sedimentation unit operation may be arranged upstream from a
reactor or condenser. In some examples, a sedimentation unit
operation may be capable of being operated in batch mode or
continuous mode.
[0100] Reactors used in systems of the disclosure rely on a heating
source to induce thermal decomposition of a waste plastic
feedstock. Moreover, other unit operations may also require a
heating source. Non-limiting examples of sources of heat that may
be included in systems of the disclosure include a heat transfer
fluid, an electrical heater, or a flame. In some examples, a
heat-exchanger may be included in systems of the disclosure with
non-limiting examples that include shell and tube heat exchangers,
plate heat exchangers, regenerative heat exchangers, recuperative
heat exchangers, adiabatic wheel heat exchangers, plate fin heat
exchangers, fluid heat exchangers, waste heat recovery units,
dynamic scraped surface heat exchanger, phase-change heat
exchangers, and spiral heat exchangers. A heating source may be in
thermal contact with an outside surface of a unit operation (e.g.,
for example, in the case of a jacketed reactor that utilizes a heat
transfer fluid in the jacket), or the heating source may be an
internal component to a unit operation that may or may not be in
mechanical contact with a material that is heated within the unit
operation.
[0101] Systems of the disclosure may include one or more chemical
additive storage vessels that may be capable of storing a chemical
additive used in methods of the disclosure. In some examples, a
chemical additive storage vessel may be capable of being held at
ambient temperature or may be capable of being held at increased or
reduced temperatures. Reduced temperature, for example, may be
useful in reducing the rate of vaporization of any volatile
chemical additives. Chemical additive storage vessels may be
capable of being held at atmospheric pressure and/or may be capable
of being pressurized in order to maximize the holding capacity of
the contained materials. Non-limiting examples of vessels that may
be capable of serving as chemical additive storage vessels that may
be included in systems of the disclosure include silos, tanks,
flasks, stills, pots, kettles, and beakers.
[0102] Systems of the disclosure may include one or more product
storage vessels. Such product storage vessels may be useful in
long-term product storage after final purification or sorting of
various components recovered from methods of the disclosure.
Product storage vessels may be capable of being held at ambient
temperature or may be capable of being temperature controlled to
prevent volatilization of the contained materials. Product storage
vessels may be capable of being held at atmospheric pressure and/or
may be capable of being pressurized in order to maximize the
holding capacity of the contained materials. Non-limiting examples
of vessels that may be capable of serving as product storage
vessels that may be included in systems of the disclosure include
silos, tanks, flasks, stills, pots, kettles, and beakers.
[0103] Systems of the disclosure may include one or more control
systems to regulate aspects of the system. The control system may
control any number of system operating parameters with non-limiting
examples that include the rates at which materials are entered into
various unit operations, the rates at which materials are consumed,
the rates at which materials are generated, the rate at which
materials are transported between unit operations, the rates at
which materials leave a system, the temperature of any unit
operation, the pressure of any unit operation, or heating rates of
any material stream or unit operation. In some examples, a control
system may be arranged with feedback control loops. Any combination
of proportional, integral, and or derivative control schemes may be
executed by a control system.
[0104] Systems of the disclosure may include sensors and/or control
valves to aid in system control. Sensors may be capable of
monitoring system parameters controlled by the control system.
Non-limiting examples of sensors that may be included in systems of
the disclosure include temperature sensors, pressure sensors,
material flow meters, material concentration sensors, scales, fluid
level indicators, or particle size sensors. Valves may be capable
of exercising control of system parameters that may need adjusting
during method execution, as indicated by an appropriate sensor.
Non-limiting examples of valves that may be included in systems of
the disclosure include pressure relief values, material flow
valves, or heat transfer fluid control valves. Control valves may
be capable of being operated manually by a chemical operator or may
be automatically controllable by a control system.
[0105] Systems of the disclosure may include one or more conveyor
belts. Conveyor belts may be useful for transporting materials
between unit operations. In some examples, systems of the
disclosure may contain one or more conveyor belts that are
consecutively staged or discontinuously staged. In some examples,
systems of the disclosure may contain one or more conveyor belts
that are staged in parallel. In some examples, a conveyor belt may
be capable of being operated in batch mode or continuous mode.
[0106] Systems of the disclosure may include one or more pumps.
Pumps may be useful for transporting materials between unit
operations. In some examples, systems of the disclosure may contain
one or more pumps that are consecutively staged or discontinuously
staged. In some examples, systems of the disclosure may contain one
or more pumps that are staged in parallel. In some examples, a pump
may be capable of being operated in batch mode or continuous
mode.
[0107] Systems of the disclosure may include one or more piping
systems. Piping systems may be useful for transporting materials
between unit operations.
[0108] Systems of the disclosure may include one or more glass
fittings that may be used to link various unit operations. Glass
fittings may be useful for transporting materials between unit
operations, especially in the case of laboratory-scale systems. An
example of a glass-fitting is a glass connector, used to connect
two pieces of glass equipment, such as, for example a glass reactor
flask and a glass condenser.
[0109] Systems of the disclosure may include unit operations that
may be pressurized. Pressurization may be achieved by putting a
unit operation under vacuum during use. In some examples, a unit
operation may be pressurized, such as with an inert gas, during
use.
EXAMPLES
Example 1
[0110] A Laboratory-scale production run in batch-mode is conducted
wherein a 1 kg waste plastic feedstock is heated with 5% w/w (50 g)
residue generated from previously heated waste plastic feedstock.
The waste plastic feedstock is generated from random amounts of
HDPE, LDPE, PP, and PS for a total weight of 1 kg. The residue is
also generated from random amounts of HDPE, LDPE, PP, and PS for a
total weight of 50 g. Moreover, the residue is not contained within
the reactor prior to heating, and is, instead, entered from a
separate heating process into a spherical glass reactor with the
waste plastic feedstock to be heated. The spherical glass reactor
is fluidly connected (via glass fittings) to a single-stage
condenser that is operated with chilled tap water. The condenser is
positioned with a negative slope (from its end fluidly connected
with the reactor--similar to the condenser shown in FIG. 6) and
fluidly connected (via glass fittings) to a product recovery flask.
Such arrangement permits gravity transport of distillate generated
during product vapor condensation. An external electrical heater
(e.g., outside of the reactor) is used to heat the feedstock with
the residue in the reactor for 310 minutes, with the set
temperature of the heater at 0 min having a value of 150.degree. C.
The set temperature of the heater is ramped at a rate of
+0.67.degree. C./min for the first 225 minutes. At 225 minutes, the
set temperature of the heater is 300.degree. C. and the set
temperature ramp rate is increased to a rate of +1.3.degree. C./min
until 300 minutes and a heater set temperature of 400.degree. C. is
reached. The set temperature of the heater is held at 400.degree.
C. for the remaining 10 minutes of the production run. A
thermocouple is used to measure the temperature in the reactor.
Observations of temperatures in the reactor and visual inspections
of the process that are recorded for the production run are shown
in Table 1.
TABLE-US-00001 TABLE 1 Temperatures and Observations of Example 1
Time- Heater Set Reaction Mixture point Temperature Temperature
(min) (.degree. C.) (.degree. C.) Observations 0 150 23
Waste-plastic feedstock is solid 15 160 70 Waste-plastic feedstock
is solid 30 170 165 Waste-plastic feedstock is solid 45 180 186
Light vapor observable in collection flask 60 190 202 Drops of
liquid distillate begin forming 75 200 215 Slow, steady drops of
liquid distillate produced 90 210 224 Drop rate of liquid
distillate formation faster 105 220 231 Drop rate of liquid
distillate faster at ~120 drops/min 120 230 238 Waste-plastic
feedstock boiling 135 240 244 Drop rate of liquid distillate faster
150 250 259 Drop rate of liquid distillate very fast 165 260 268
Vapor showing in collection flask 180 270 275 Sample at rolling
boil and sustained drop rate of liquid distillate 195 280 287
Liquid distillate is transparent 210 290 291 Drop rate of liquid
distillate continues to be sustained 225 300 299 Drop rate of
liquid distillate continues to be sustained 240 320 322 Drop rate
of liquid distillate continues to be sustained; distillate has
color 255 340 346 Drop rate of liquid distillate ~92 drops/min 270
360 371 Drop rate of liquid distillate sustained 285 380 382
Distillate now appears to have light black color 300 400 389 Drop
rate of liquid distillate slowing 310 400 389 Drop rate of liquid
distillate slowing
[0111] At the conclusion of the production run (e.g., 310 minutes),
the liquid distillate that is collected from condensation is massed
and its volume taken. A distillate weight of 817.4 g is recorded,
having a volume of 1020 mL. A density of the distillate is
calculated as the ratio of mass recorded from weighing the
distillate to the measured volume of the distillate. A density of
0.80 g/mL is recorded for the distillate. A mass conversion (mass
conversion=(mass of distillate/mass of waste plastic feedstock
entered into the reactor).times.100%) is also calculated for the
production process, with a value of 81.74%. The distillate is
observed to be dark yellow in color and ignites during a flame
test. A summary of the experimental results of Example 1 is shown
in Table 5.
Example 2
[0112] A laboratory-scale production run in batch-mode is conducted
wherein a 1 kg waste plastic feedstock is heated with 10% w/w (100
g) residue generated from previously heated waste plastic
feedstock. The waste plastic feedstock is generated from random
amounts of HDPE, LDPE, PP, and PS for a total weight of 1 kg. The
residue is also generated from random amounts HDPE, LDPE, PP, and
PS for a total weight of 100 g. Moreover, the residue is not
contained within the reactor prior to heating, and is, instead,
entered from a separate heating process into a spherical glass
reactor with the waste plastic feedstock to be heated. The
spherical glass reactor is fluidly connected (via glass fittings)
to a single-stage condenser that is operated with chilled tap
water. The condenser is positioned with a negative slope (from its
end fluidly connected with the reactor--similar to the condenser
shown in FIG. 6) and fluidly connected (via glass fittings) to a
product recovery flask. Such arrangement permits gravity transport
of distillate generated during product vapor condensation. An
external electrical heater (e.g., outside of the reactor) is used
to heat the feedstock with the residue in the reactor for 300
minutes, with the set temperature of the heater at 0 min having a
value of 150.degree. C. The set temperature of the heater is ramped
at a rate of +0.67.degree. C./min for the first 225 minutes. At 225
minutes, the set temperature of the heater is 300.degree. C. and
the set temperature ramp rate is increased to a rate of
+1.3.degree. C./min until 300 minutes and a heater set temperature
of 400.degree. C. is reached. The production run is concluded at
300 minutes. A thermocouple is used to measure the temperature in
the reactor. Observations of temperatures in the reactor and visual
inspections of the process that are recorded for the production run
are shown in Table 2.
TABLE-US-00002 TABLE 2 Temperatures and Observations of Example 2
Time- Heater Set Reaction Mixture point Temperature Temperature
(min) (.degree. C.) (.degree. C.) Observations 0 150 22
Waste-plastic feedstock is solid 15 160 69 Waste-plastic feedstock
is solid 30 170 150 Light vapor observable in collection flask 45
180 192 Waste-plastic feedstock melting 60 190 232 First drop of
liquid distillate observed 75 200 238 Drop rate of liquid
distillate slow 90 210 243 Clear colored liquid distillate observed
105 220 249 Drop rate of liquid distillate of ~97 drops/min 120 230
255 Melted waste-plastic feedstock boiling 135 240 258 Drop rate of
liquid distillate fast 150 250 261 Drop rate of liquid distillate
slows some 165 260 267 Drop rate of liquid distillate at ~88
drops/min 180 270 272 Drop rate of liquid distillate speeds up 195
280 281 Some vapor observed in collection flask 210 290 288 Clear
colored liquid distillate observed 225 300 297 Drop rate of liquid
distillate of ~77 drops/min 240 320 312 Drop rate of liquid
distillate sustained 255 340 326 Drop rate of liquid distillate
sustained 270 360 348 Distillate now appears to have light black
color 285 380 367 Drop rate of liquid distillate slows considerably
300 400 388 No additional production of liquid distillate
[0113] At the conclusion of the production run (e.g., 300 minutes),
the liquid distillate that is collected from condensation is massed
and its volume taken. A distillate weight of 821 g is recorded,
having a volume of 1038 mL. A density of the distillate is
calculated as the ratio of mass recorded from weighing the
distillate to the measured volume of the distillate. A density of
0.79 g/mL is recorded for the distillate. A mass conversion is also
calculated for the production process, with a value of 82.1%. The
distillate is observed to be dark yellow in color and ignites
during a flame test. A summary of the experimental results of
Example 2 is shown in Table 5.
Example 3
[0114] A laboratory-scale production run in batch-mode is conducted
wherein a 1 kg waste plastic feedstock is heated with 20% w/w (200
g) residue generated from previously heated waste plastic
feedstock. The waste plastic feedstock is generated from random
amounts of HDPE, LDPE, PP, and PS for a total weight of 1 kg. The
residue is also generated from random amounts HDPE, LDPE, PP, and
PS for a total weight of 200 g. Moreover, the residue is not
contained within the reactor prior to heating, and is, instead,
entered from a separate heating process into a spherical glass
reactor with the waste plastic feedstock to be heated. The
spherical glass reactor is fluidly connected (via glass fittings)
to a single-stage condenser that is operated with chilled tap
water. The condenser is positioned with a negative slope (from its
end fluidly connected with the reactor--similar to the condenser
shown in FIG. 6) and fluidly connected (via glass fittings) to a
product recovery flask. Such arrangement permits gravity transport
of distillate generated during product vapor condensation. An
external electrical heater (e.g., outside of the reactor) is used
to heat the feedstock with the residue in the reactor for 270
minutes, with the set temperature of the heater at 0 min having a
value of 200.degree. C. The set temperature of the heater is ramped
at a rate of +0.67.degree. C./min for the first 165 minutes. At 165
minutes, the set temperature of the heater is 310.degree. C. and
the set temperature ramp rate is increased to a rate of
+1.3.degree. C./min until 240 minutes and a heater set temperature
of 400.degree. C. is reached. The set temperature is held at
400.degree. C. for 15 additional minutes to reach 255 minutes. At
255 minutes, the temperature is further ramped at a rate of
+0.67.degree. C. to a temperature of 410.degree. C., achieved at
270 minutes. At 270 minutes the production run concludes. A
thermocouple is used to measure the temperature in the reactor.
Observations of temperatures in the reactor and visual inspections
of the process that are recorded for the production run are shown
in Table 3.
TABLE-US-00003 TABLE 3 Temperatures and Observations of Example 3
Time- Heater Set Reaction Mixture point Temperature Temperature
(min) (.degree. C.) (.degree. C.) Observations 0 200 23
Waste-plastic feedstock is solid 15 210 72 Light vapor observable
in collection flask 30 220 152 Waste-plastic feedstock melting 45
230 198 First drop of liquid distillate observed 60 240 242 Drop
rate of liquid distillate slow 75 250 248 Clear colored liquid
distillate observed 90 260 257 Drop rate of liquid distillate of
~76 drops/min 105 270 264 Melted waste-plastic feedstock boiling
120 280 278 Drop rate of liquid distillate fast 135 290 286 Drop
rate of liquid distillate slows some 150 300 293 Drop rate of
liquid distillate at ~92 drops/min 165 310 305 Drop rate of liquid
distillate speeds up 180 330 320 Clear colored liquid distillate
observed 195 350 339 Waste-plastic feedstock at rolling boil 210
370 355 Drop rate of liquid distillate sustained 225 390 373
Distillate now appears to have light black color 240 400 385 Drop
rate of liquid distillate slows some; white vapor 255 400 387 Drop
rate of liquid distillate slows more 270 410 389 No additional
production of liquid distillate
[0115] At the conclusion of the production run (e.g., 270 minutes),
the liquid distillate that is collected from condensation is massed
and its volume taken. A distillate weight of 816.13 g is recorded,
having a volume of 1030 mL. A density of the distillate is
calculated as the ratio of mass recorded from weighing the
distillate to the measured volume of the distillate. A density of
0.79 g/mL is recorded for the distillate. A mass conversion is also
calculated for the production process, with a value of 81.61%. The
distillate is observed to be dark yellow in color and ignites
during a flame test. A summary of the experimental results of
Example 3 is shown in Table 5.
Example 4
[0116] High-density polyethylene (HDPE) waste plastic is collected
and cleaned manually with soap and water. The waste plastic is then
first cut into small pieces (approximately 5-6 in.sup.2 in area)
using scissors. A secondary size-reduction modality is utilized
with the scissor-cut waste plastic further ground, using a grinder,
to produce a waste plastic feedstock of comprised of waste plastic
pieces about 3-4 mm in diameter. A laboratory-scale, batch-mode
process is employed with 750 g of the ground waste plastic
feedstock entered into a reactor that contains adhered residue from
a previously heated feedstock. No additional external catalyst is
added to the system. The reactor is heated using an electrical
heater with an initial heater set temperature of 100.degree. C. and
ramped continuously to a final heater set temperature of
420.degree. C., over the course of 5-6 hours.
[0117] Throughout the course of increased heating, the waste
plastic feedstock melts, with subsequent volatilization of lower
molecular-weight hydrocarbons into a vapor stream. Between
260-340.degree. C., a substantial vapor stream is generated. This
vapor stream is directed to pass through a fractional distillation
column for separation into its component hydrocarbons. A mixture of
hydrocarbons that have lower carbon-chain lengths ("light fuel"),
and, thus, generally lower boiling temperatures ("light fuel") are
collected at the top of the fractional distillation column and a
mixture of longer carbon-chain heavier hydrocarbons ("heavy fuel")
are collected from the bottom of the fractional distillation
column. Light fuel is passed through an alkali-containing scrubber
to remove contaminants and then transferred into a Teflon bag for
further analysis. Collected liquid heavy fuel is further purified
using centrifugal and filtration devices.
[0118] Light fuel is determined to contain methane, ethane,
propane, and butane due to the very low boiling points of these
species. Produced liquid heavy fuel has a weight of 135 g and a
volume of 160 mL to give a density of 0.84 g/ml. A mass-conversion
of heavy fuel generated by the vapor stream obtained from heating
temperatures 260-340.degree. C. is determined to be 18%. 562.5 g of
fuel was obtained at other temperatures of the heating ramp (i.e.,
temperatures outside the range 260-340.degree. C.), for a total
mass-conversion of 75%. By mass, 30 g of light fuel was generated
for a mass-conversion of 4%. The total mass-conversion (e.g., light
fuel+heavy fuel+fuel obtained at temperatures outside
260-340.degree. C.) for the process is 97%. The heavy fuel fraction
that is obtained is further separated with gas chromatography and
detected with a mass spectrometer, to determine the component
hydrocarbons of the heavy fuel mixture. Gas chromatograph is set at
an initial temperature of 40.degree. C. and a final temperature of
325.degree. C., with a heating rate of 0.67.degree. C./min and held
at the final temperature for 15 min. Mass spectrometer is set to
detect eluting species with mass-to-charge ratio (m/z) of
35.00-528.00, with a solvent delay of 1 min. Standards of
hydrocarbons in the C.sub.5-C.sub.28 range are used for
determinations. A total of 36 distinct species are identified and
summarized, with retention time and molecular-weight in Table
4.
TABLE-US-00004 TABLE 4 GC/MS Analysis of hydrocarbon components in
collected heavy fuel from temperature 260.degree. C. to 340.degree.
C. Peak Retention Compound Molecular Number Time (min) Compound
Name Formula Weight 1 1.89 Cyclopropane, ethyl- C.sub.5H.sub.10 70
2 1.93 Pentane C.sub.5H.sub.12 72 3 2.51 1-Hexene C.sub.6H.sub.12
84 4 2.58 Hexane C.sub.6H.sub.14 86 5 3.63 1-Heptene
C.sub.7H.sub.14 98 6 3.75 Heptane C.sub.7H.sub.16 100 7 5.17
1-Octene C.sub.8H.sub.16 112 8 5.33 Octane C.sub.8H.sub.18 114 9
6.90 1-Nonene C.sub.9H.sub.18 126 10 7.06 Nonane C.sub.9H.sub.20
128 11 8.63 1-Decene C.sub.10H.sub.20 140 12 8.78 Decane
C.sub.10H.sub.22 142 13 10.29 1-Undecene C.sub.11H.sub.22 154 14
10.43 Undecane C.sub.11H.sub.24 156 15 11.85 1-Dodecene
C.sub.12H.sub.24 168 16 11.98 Dodecane C.sub.12H.sub.26 170 17
13.32 1-Tridecene C.sub.13H.sub.26 182 18 13.43 Tridecane
C.sub.10H.sub.28 184 19 14.70 1-Tetradecene C.sub.14H.sub.28 196 20
14.81 Tetradecane C.sub.14H.sub.30 198 21 16.01 1-Pentadecene
C.sub.15H.sub.30 210 22 16.11 Pentadecane C.sub.15H.sub.32 212 23
17.26 1-Hexadecene C.sub.16H.sub.32 224 24 17.36 Hexadecane
C.sub.16H.sub.34 226 25 18.46 3-Heptadecene, (Z)- C.sub.17H.sub.34
238 26 18.56 Heptadecane C.sub.17H.sub.36 240 27 19.62 1-Eicosene
C.sub.20H.sub.40 280 28 19.73 Octadecane C.sub.18H.sub.38 254 29
20.87 Eicosane C.sub.20H.sub.42 282 30 21.63 1-Docosanol
C.sub.22H.sub.46O 326 31 22.05 Eicosane C.sub.20H.sub.42 282 32
23.27 Heneicosane C.sub.21H.sub.44 296 33 24.63 Octacosane
C.sub.28H.sub.58 394 34 26.20 Octacosane C.sub.28H.sub.58 394 35
28.11 Tetracosane C.sub.24H.sub.50 338 36 30.62 Heptacosane
C.sub.27H.sub.56 380
Example 5
[0119] A laboratory-scale production run in batch-mode is conducted
wherein 75 g of computer body are heated with 7.5 g of zinc oxide
and 7.5 g of activated carbon in a spherical glass reactor also
comprising residue produced from a previously heated source of
waste plastic. The spherical glass reactor is fluidly connected
(via glass fittings) to a single-stage condenser that is operated
with chilled tap water. The condenser is positioned with a negative
slope (from its end fluidly connected with the reactor--similar to
the condenser shown in FIG. 6) and fluidly connected (via glass
fittings) to a product recovery flask. Such arrangement permits
gravity transport of distillate generated during product vapor
condensation. An external electrical heater (e.g., outside of the
reactor) is used to heat the feedstock with the residue in the
reactor for 310 minutes, with the set temperature of the heater at
0 min having a value of 150.degree. C. The set temperature of the
heater is ramped at a rate of +0.67.degree. C./min for the first
225 minutes. At 225 minutes, the set temperature of the heater is
300.degree. C. and the set temperature ramp rate is increased to a
rate of +1.3.degree. C./min until 300 minutes and a heater set
temperature of 400.degree. C. is reached. The set temperature of
the heater is held at 400.degree. C. for the remaining 10 minutes
of the production run. A thermocouple is used to measure the
temperature in the reactor.
[0120] At the conclusion of the production run (e.g., 310 minutes),
the liquid distillate that is collected from condensation is massed
and its volume taken. A distillate weight of 55.7 g is recorded,
having a volume of 63 mL. A density of the distillate is calculated
as the ratio of mass recorded from weighing the distillate to the
measured volume of the distillate. A density of 0.88 g/mL is
recorded for the distillate. A mass conversion (mass
conversion=(mass of distillate/mass of waste plastic feedstock
entered into the reactor).times.100%) is also calculated for the
production process, with a value of 74.26%. The distillate is
observed to be dark yellow in color and ignites during a flame
test.
Example 6
[0121] A laboratory-scale production run in batch-mode is conducted
wherein 100 g of scrap tires are heated with 1 g of ferric
carbonate in a spherical glass reactor also comprising residue
produced from a previously heated source of waste plastic. The
spherical glass reactor is fluidly connected (via glass fittings)
to a single-stage condenser that is operated with chilled tap
water. The condenser is positioned with a negative slope (from its
end fluidly connected with the reactor--similar to the condenser
shown in FIG. 6) and fluidly connected (via glass fittings) to a
product recovery flask. Such arrangement permits gravity transport
of distillate generated during product vapor condensation. An
external electrical heater (e.g., outside of the reactor) is used
to heat the feedstock with the residue in the reactor for 310
minutes, with the set temperature of the heater at 0 min having a
value of 150.degree. C. The set temperature of the heater is ramped
at a rate of +0.67.degree. C./min for the first 225 minutes. At 225
minutes, the set temperature of the heater is 300.degree. C. and
the set temperature ramp rate is increased to a rate of
+1.3.degree. C./min until 300 minutes and a heater set temperature
of 400.degree. C. is reached. The set temperature of the heater is
held at 400.degree. C. for the remaining 10 minutes of the
production run. A thermocouple is used to measure the temperature
in the reactor.
[0122] At the conclusion of the production run (e.g., 310 minutes),
the liquid distillate that is collected from condensation is massed
and its volume taken. A distillate weight of 21.1 g is recorded,
having a volume of 25 mL. A density of the distillate is calculated
as the ratio of mass recorded from weighing the distillate to the
measured volume of the distillate. A density of 0.84 g/mL is
recorded for the distillate. A mass conversion (mass
conversion=(mass of distillate/mass of waste plastic feedstock
entered into the reactor).times.100%) is also calculated for the
production process, with a value of 21.1%. The distillate is
observed to be dark yellow in color and ignites during a flame
test.
Example 7
[0123] A laboratory-scale production run in batch-mode is conducted
wherein 75 g of scrap electrical cable (e.g., comprising an
electrical cable casing) are heated with 3.75 g of sodium hydroxide
and 3.75 g of activated carbon in a spherical glass reactor also
comprising residue produced from a previously heated source of
waste plastic. The spherical glass reactor is fluidly connected
(via glass fittings) to a single-stage condenser that is operated
with chilled tap water. The condenser is positioned with a negative
slope (from its end fluidly connected with the reactor--similar to
the condenser shown in FIG. 6) and fluidly connected (via glass
fittings) to a product recovery flask. Such arrangement permits
gravity transport of distillate generated during product vapor
condensation. An external electrical heater (e.g., outside of the
reactor) is used to heat the feedstock with the residue in the
reactor for 310 minutes, with the set temperature of the heater at
0 min having a value of 150.degree. C. The set temperature of the
heater is ramped at a rate of +0.67.degree. C./min for the first
225 minutes. At 225 minutes, the set temperature of the heater is
300.degree. C. and the set temperature ramp rate is increased to a
rate of +1.3.degree. C./min until 300 minutes and a heater set
temperature of 400.degree. C. is reached. The set temperature of
the heater is held at 400.degree. C. for the remaining 10 minutes
of the production run. A thermocouple is used to measure the
temperature in the reactor.
[0124] At the conclusion of the production run (e.g., 310 minutes),
the liquid distillate that is collected from condensation is massed
and its volume taken. A distillate weight of 25.2 g is recorded,
having a volume of 28 mL. A density of the distillate is calculated
as the ratio of mass recorded from weighing the distillate to the
measured volume of the distillate. A density of 0.90 g/mL is
recorded for the distillate. A mass conversion (mass
conversion=(mass of distillate/mass of waste plastic feedstock
entered into the reactor).times.100%) is also calculated for the
production process, with a value of 33.6%. The distillate is
observed to be dark yellow in color and ignites during a flame
test.
TABLE-US-00005 TABLE 5 Experimental results of production runs in
Example 1, Example 2, Example 3, Example 5, Example 6, and Example
7. Weight Weight of Fraction Total Total Waste of Initial Heater
Final Heater Liquid Liquid Liquid Reaction Plastic Added Set Set
Distillate Distillate Distillate Mass Example Time Feedstock
Residue Temperature Temperature Volume Mass Density Conversion
Ignition? (#) (min) (g) (%) (.degree. C.) (.degree. C.) (mL) (g)
(g/mL) (%) (YES/NO) 1 310 1000 5 150 400 1020 817.4 0.80 81.74 YES
2 300 1000 10 150 400 1038 821 0.79 82.1 YES 3 270 1000 20 200 410
1030 816.13 0.79 81.61 YES 5 310 75 0 150 400 63 55.7 0.88 74.26
YES 6 310 100 0 150 400 25 21.1 0.84 21.10 YES 7 310 75 0 150 400
28 25.2 0.90 33.60 YES
[0125] It should be understood from the foregoing that, while
particular implementations have been illustrated and described,
various modifications can be made thereto and are contemplated
herein. It is also not intended that the invention be limited by
the specific examples provided within the specification. While the
invention has been described with reference to the aforementioned
specification, the descriptions and illustrations of the preferable
embodiments herein are not meant to be construed in a limiting
sense. Furthermore, it shall be understood that all aspects of the
invention are not limited to the specific depictions,
configurations or relative proportions set forth herein which
depend upon a variety of conditions and variables. Various
modifications in form and detail of the embodiments of the
invention will be apparent to a person skilled in the art. It is
therefore contemplated that the invention shall also cover any such
modifications, variations and equivalents. It is intended that the
following claims define the scope of the invention and that methods
and structures within the scope of these claims and their
equivalents be covered thereby.
* * * * *