U.S. patent application number 14/472263 was filed with the patent office on 2015-05-21 for process for removing a contaminant from coal tar.
The applicant listed for this patent is UOP LLC. Invention is credited to Robert L. Bedard, Jayant K. Gorawara, Deng-Yang Jan, Gregory F. Maher, Dean E. Rende.
Application Number | 20150136660 14/472263 |
Document ID | / |
Family ID | 53172218 |
Filed Date | 2015-05-21 |
United States Patent
Application |
20150136660 |
Kind Code |
A1 |
Bedard; Robert L. ; et
al. |
May 21, 2015 |
PROCESS FOR REMOVING A CONTAMINANT FROM COAL TAR
Abstract
A process for removing at least one contaminant from coal tar is
described. The process involves extraction with an extraction agent
or adsorption with an adsorbent. The extraction agent includes at
least one of amphiphilic block copolymers, inclusion complexes of
poly(methyl methacrylate) and polycyclic aromatic hydrocarbons,
cyclodextrins, functionalized cyclodextrins, and
cyclodextrin-functionalized polymers, and the adsorbent includes
exfoliated graphite oxide, thermally exfoliated graphite oxide or
intercalated graphite compounds.
Inventors: |
Bedard; Robert L.; (McHenry,
IL) ; Gorawara; Jayant K.; (Buffalo Grove, IL)
; Jan; Deng-Yang; (Elk Grove Village, IL) ; Maher;
Gregory F.; (Aurora, IL) ; Rende; Dean E.;
(Arlington Heights, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UOP LLC |
Des Plaines |
IL |
US |
|
|
Family ID: |
53172218 |
Appl. No.: |
14/472263 |
Filed: |
August 28, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61905895 |
Nov 19, 2013 |
|
|
|
Current U.S.
Class: |
208/435 ;
208/289; 208/290; 208/291; 208/293; 208/295; 208/301; 208/302;
208/428; 208/87; 208/91 |
Current CPC
Class: |
C10G 25/003 20130101;
C10G 57/00 20130101; C10G 57/005 20130101; C10C 1/20 20130101; C10G
67/04 20130101; C10G 25/03 20130101; C10G 21/16 20130101; C10G
67/06 20130101; C10G 21/14 20130101; C10C 1/18 20130101; C10G 55/06
20130101; C10G 21/02 20130101 |
Class at
Publication: |
208/435 ;
208/291; 208/302; 208/289; 208/91; 208/428; 208/290; 208/295;
208/293; 208/301; 208/87 |
International
Class: |
C10G 21/02 20060101
C10G021/02; C10G 25/00 20060101 C10G025/00; C10G 21/16 20060101
C10G021/16; C10G 67/06 20060101 C10G067/06; C10G 57/00 20060101
C10G057/00; C10G 55/06 20060101 C10G055/06; C10G 67/04 20060101
C10G067/04; C10G 1/00 20060101 C10G001/00; C10G 21/14 20060101
C10G021/14 |
Claims
1. A process for removing at least one contaminant from coal tar
comprising: providing at least a portion of a coal tar stream;
removing at least one contaminant from the at least the portion of
the coal tar stream by extraction with an extraction agent or
adsorption with an adsorbent to form a treated coal tar stream
having a reduced level of the at least one contaminant, the
extraction agent comprising at least one of amphiphilic block
copolymers, inclusion complexes of poly(methyl methacrylate) and
polycyclic aromatic hydrocarbons, cyclodextrins, functionalized
cyclodextrins, and cyclodextrin-functionalized polymers, the
adsorbent comprising exfoliated graphite oxide, thermally
exfoliated graphite oxide or intercalated graphite compounds, and
the at least one contaminant comprising nitrogen heterocyclic
aromatics, oxygen heterocyclic aromatics, and sulfur heterocyclic
aromatics; separating the at least the portion of the coal tar
stream into at least two fractions.
2. The process of claim 1 wherein the extraction agent comprises
the amphiphilic block copolymer, and wherein the amphiphilic block
copolymer comprises at least two blocks selected from polyethylene
oxide blocks, polypropylene oxide blocks, butylene oxide blocks,
silicone blocks, urethane blocks, polyurethane ionomer blocks,
acrylate ionomer blocks, polymethylacryate blocks, polyacrylic acid
blocks, and polyvinylidene chloride blocks.
3. The process of claim 1 wherein the extraction agent further
comprises an ionic liquid, or a supercritical fluid, or both.
4. The process of claim 3 wherein the extraction agent further
comprises the ionic liquid, and wherein the ionic liquid is
selected from imidazolium-based ionic liquid, pyrrolidinium-based
ionic liquid, pyridinium-based ionic liquid, sulphonium-based ionic
liquids, phosphonium-based ionic liquids, and ammonium-based ionic
liquids.
5. The process of claim 3 wherein the extraction agent further
comprises the supercritical fluid, and wherein the supercritical
fluid comprises supercritical carbon dioxide, supercritical
ammonia, supercritical ethane, supercritical propane, supercritical
butane, or supercritical water.
6. The process of claim 5 wherein the supercritical fluid is the
supercritical ammonia, wherein one of the separated fractions
comprises ammonia, and wherein the ammonia in the fraction is
processed into the supercritical ammonia.
7. The process of claim 5 wherein the supercritical fluid is the
supercritical carbon dioxide, wherein one of the separated
fractions comprises carbon dioxide, and wherein the carbon dioxide
in the fraction is processed into the supercritical carbon
dioxide.
8. The process of claim 1 wherein at least two contaminants are
removed, and wherein the first contaminant is removed using a first
extraction agent or adsorbent and wherein the second contaminant is
removed using a second extraction agent or adsorbent after the
removal of the first contaminant and before separating the at least
the portion of the coal tar stream into the at least two
fractions.
9. The process of claim 1 further comprising removing at least one
additional contaminant by adsorption with a second adsorbent, or an
oxidation reaction, the at least one additional contaminant
comprising arsenic, metal compounds, mercury halides, elemental
mercury, inorganic halides, organic halides, and coal tar
insolubles, and wherein the second adsorbent comprises a noble
metal deposited on a support selected from the group consisting of
molecular sieves, alumina, activated carbons, and silica gel;
silver impregnated zeolite selected from the group consisting of
faujasites (13X, CaX, NaY, CaY, and ZnX), chabazites,
clinoptilolites and LTA (3A, 4A, 5A) zeolites; sulfur or a metal
sulfide on an activated carbon support or an activated alumina
support; or a metal sulfide, metal oxide, or metal carbonate on a
support, the metal is selected from the group consisting of copper,
silver, gold, antimony, lead, and manganese, and the support
selected from the group consisting of activated alumina, clay, or
activated carbon.
10. The process of claim 1 further comprising reducing a viscosity
of the at least the portion of the coal tar stream before removing
the at least one contaminant.
11. The process of claim 10 wherein the viscosity is reduced by
mixing the at least the portion of the coal tar fraction with a
solvent.
12. The process of claim 1 further comprising processing at least
one of the fractions to produce at least one product.
13. The process of claim 12 wherein the at least one fraction is
processed by at least one of hydrotreating, hydrocracking, fluid
catalytic cracking, alkylation, transalkylation, oxidation, or
hydrogenation.
14. The process of claim 1 wherein the at least one contaminant is
removed before the at least the portion of the coal tar stream is
separated into the at least two fractions.
15. The process of claim 1 wherein the at least one contaminant is
removed after the at least the portion of the coal tar stream is
separated into the at least two fractions.
16. A process for removing at least one contaminant from coal tar
comprising: pyrolyzing a coal feed into a coal tar stream and a
coke stream; removing at least one contaminant from at least a
portion of the coal tar stream by extraction with an extraction
agent or adsorption with an adsorbent to form a treated coal tar
stream having a reduced level of the at least one contaminant, the
extraction agent comprising at least one of amphiphilic block
copolymers, inclusion complexes of poly(methyl methacrylate) and
polycyclic aromatic hydrocarbons, cyclodextrins, functionalized
cyclodextrins, and cyclodextrin-functionalized polymers, the
adsorbent comprising exfoliated graphite oxide, thermally
exfoliated graphite oxide or intercalated graphite compounds, and
the at least one contaminant comprising nitrogen heterocyclic
aromatics, oxygen heterocyclic aromatics, and sulfur heterocyclic
aromatics: separating the coal tar portion into at least two
fractions: and processing at least one of the fractions to produce
at least one product.
17. The process of claim 16 wherein the extraction agent comprises
the amphiphilic block copolymer, and wherein the amphiphilic block
copolymer comprises at least two blocks selected from polyethylene
oxide blocks, polypropylene oxide blocks, butylene oxide blocks,
silicone blocks, urethane blocks, polyurethane ionomer blocks,
acrylate ionomer blocks, polymethylacryate blocks, polyacrylic acid
blocks, and polyvinylidene chloride blocks.
18. The process of claim 16 wherein the extraction agent further
comprises an ionic liquid, or a supercritical fluid, or both.
19. The process of claim 16 further comprising reducing a viscosity
of the coal tar fraction before removing the at least one
contaminant.
20. The process of claim 16 wherein the at least one fraction is
processed by at least one of hydrotreating, hydrocracking, fluid
catalytic cracking, alkylation, transalkylation, oxidation, or
hydrogenation.
Description
[0001] This application claims the benefit of Provisional
Application Ser. No. 61/905,895 filed Nov. 19, 2013, entitled
Process for Removing a Contaminant from Coal Tar.
BACKGROUND OF THE INVENTION
[0002] Many different types of chemicals are produced from the
processing of petroleum. However, petroleum is becoming more
expensive because of increased demand in recent decades.
[0003] Therefore, attempts have been made to provide alternative
sources for the starting materials for manufacturing chemicals.
Attention is now being focused on producing liquid hydrocarbons
from solid carbonaceous materials, such as coal, which is available
in large quantities in countries such as the United States and
China.
[0004] Pyrolysis of coal produces coke and coal tar. The
coke-making or "coking" process consists of heating the material in
closed vessels in the absence of oxygen to very high temperatures.
Coke is a porous but hard residue that is mostly carbon and
inorganic ash, which is used in making steel.
[0005] Coal tar is the volatile material that is driven off during
heating, and it comprises a mixture of a number of hydrocarbon
compounds. It can be separated to yield a variety of organic
compounds, such as benzene, toluene, xylene, naphthalene,
anthracene, and phenanthrene. These organic compounds can be used
to make numerous products, for example, dyes, drugs, explosives,
flavorings, perfumes, preservatives, synthetic resins, and paints
and stains but may also be processed into fuels and petrochemical
intermediates. The residual pitch left from the separation is used
for paving, roofing, waterproofing, and insulation.
[0006] Coal tar has a number of contaminants that need to be
removed, such as nitrogen, oxygen, or sulfur-containing
compounds.
[0007] There is a need for additional processes for removing
contaminants from coal tar.
SUMMARY OF THE INVENTION
[0008] One aspect of the invention is a process for removing at
least one product from coal tar. In one embodiment, the process
includes providing at least a portion of a coal tar stream;
removing at least one contaminant from the at least the portion of
the coal tar stream by extraction with an extraction agent or
adsorption with an adsorbent to form a treated coal tar stream
having a reduced level of the at least one contaminant, the
extraction agent comprising at least one of amphiphilic block
copolymers, inclusion complexes of poly(methyl methacrylate) and
polycyclic aromatic hydrocarbons, cyclodextrins, functionalized
cyclodextrins, and cyclodextrin-functionalized polymers, the
adsorbent comprising exfoliated graphite oxide, thermally
exfoliated graphite oxide or intercalated graphite compounds, and
the at least one contaminant comprising nitrogen heterocyclic
aromatics, oxygen heterocyclic aromatics, and sulfur heterocyclic
aromatics; and separating the at least the portion of the coal tar
stream into at least two fractions.
BRIEF DESCRIPTION OF THE DRAWING
[0009] The FIGURE is an illustration of one embodiment of the
process of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0010] The FIGURE shows one embodiment of a coal conversion process
5. The coal feed 10 can be sent to the pyrolysis zone 15, the
gasification zone 20, or the coal feed 10 can be split into two
parts and sent to both.
[0011] In the pyrolysis zone 15, the coal is heated at high
temperature, e.g., up to about 2,000.degree. C. (3600.degree. F.),
in the absence of oxygen to drive off the volatile components.
Coking produces a coke stream 25 and a coal tar stream 30. The coke
stream 25 can be used in other processes, such as the manufacture
of steel.
[0012] The coal tar stream 30 which comprises the volatile
components from the coking process can be sent to an optional
contaminant removal zone 35, if desired.
[0013] The contaminant removal zone 35 for removing one or more
contaminants from the coal tar stream or another process stream may
be located at various positions along the process depending on the
impact of the particular contaminant on the product or process and
the reason for the contaminant's removal, as described further
below. For example, the contaminant removal zone 35 can be
positioned upstream of the separation zone 45, as shown in the
FIGURE. Some contaminants have been identified to interfere with a
downstream processing step or hydrocarbon conversion process, in
which case the contaminant removal zone 35 may be positioned
upstream of the separation zone 45 or between the separation zone
45 and the particular downstream processing step at issue. Still
other contaminants have been identified that should be removed to
meet particular product specifications. Where it is desired to
remove multiple contaminants from the hydrocarbon or process
stream, various contaminant removal zones may be positioned at
different locations along the process. In still other approaches, a
contaminant removal zone may overlap or be integrated with another
process within the system, in which case the contaminant may be
removed during another portion of the process, including, but not
limited to the separation zone or the downstream hydrocarbon
conversion zone. This may be accomplished with or without
modification to these particular zones, reactors, or processes.
While the contaminant removal zone is often positioned downstream
of the hydrocarbon conversion reactor, it should be understood that
the contaminant removal zone in accordance herewith may be
positioned upstream of the separation zone, between the separation
zone and the hydrocarbon conversion zone, or downstream of the
hydrocarbon conversion zone or along other streams within the
process stream, such as, for example, a carrier fluid stream, a
fuel stream, an oxygen source stream, or any streams used in the
systems and the processes described herein. The contaminant
concentration is controlled by removing at least a portion of the
contaminant from the coal tar stream 30. As used herein, the term
removing may refer to actual removal, for example by adsorption,
absorption, or membrane separation, or it may refer to conversion
of the contaminant to a more tolerable compound, or both.
[0014] Conventional contaminant removal methods can be used for the
optional contaminant removal zone 35, including, but not limited
to, adsorption and oxidation. Typical adsorbents include, but are
not limited to, a noble metal deposited on a support selected from
the group consisting of molecular sieves, alumina, activated
carbons, and silica gel; silver impregnated zeolite selected from
the group consisting of faujasites (13X, CaX, NaY, CaY, and ZnX),
chabazites, clinoptilolites and LTA (3A, 4A, 5A) zeolites; sulfur
or a metal sulfide on an activated carbon support or an activated
alumina support; or a metal sulfide, metal oxide, or metal
carbonate on a support, the metal is selected from the group
consisting of copper, silver, gold, antimony, lead, and manganese,
and the support selected from the group consisting of activated
alumina, clay, or activated carbon.
[0015] The viscosity of the coal tar stream can be reduced before
it is contacted with the extraction agent or adsorbent using any
suitable method, if desired. The viscosity can be reduced before or
after the optional contaminant removal zone, for example. Suitable
methods for reducing the viscosity of the coal tar stream include,
but are not limited to, mixing the coal tar stream with a solvent
(not shown).
[0016] The decontaminated coal tar stream 40 from the contaminant
removal zone 35 is sent to a separation zone 45 where it is
separated into two or more fractions. Coal tar comprises a complex
mixture of heterocyclic aromatic compounds and their derivatives
with a wide range of boiling points. The number of fractions and
the components in the various fractions can be varied as is well
known in the art. A typical separation process involves separating
the coal tar into four to six streams. For example, there can be a
fraction comprising NH.sub.3, CO, and light hydrocarbons, a light
oil fraction with boiling points between 0.degree. C. and
180.degree. C., a middle oil fraction with boiling points between
180.degree. C. to 230.degree. C., a heavy oil fraction with boiling
points between 230 to 270.degree. C., an anthracene oil fraction
with boiling points between 270.degree. C. to 350.degree. C., and
pitch.
[0017] The light oil fraction contains compounds such as benzenes,
toluenes, xylenes, naphtha, coumarone-indene, dicyclopentadiene,
pyridine, and picolines. The middle oil fraction contains compounds
such as phenols, cresols and cresylic acids, xylenols, naphthalene,
high boiling tar acids, and high boiling tar bases. The heavy oil
fraction contains benzene absorbing oil and creosotes. The
anthracene oil fraction contains anthracene. Pitch is the residue
of the coal tar distillation containing primarily aromatic
hydrocarbons and heterocyclic compounds.
[0018] As illustrated, the coal tar feed 40 is separated into gas
fraction 50 containing gases such as NH.sub.3 and CO as well as
light hydrocarbons, such as ethane, hydrocarbon fractions 55, 60,
and 65 having different boiling point ranges, and pitch fraction
70.
[0019] Suitable separation processes include, but are not limited
to fractionation, solvent extraction, and adsorption.
[0020] One or more of the fractions 50, 55, 60, 65, 70 can be
further processed, as desired.
[0021] As illustrated, fraction 60 is sent to treatment zone 61 for
extraction or adsorption.
[0022] In an extraction process, an extraction agent stream 62 is
introduced into the treatment zone 61 and contacts the
decontaminated coal tar stream. The extraction agent stream 62 can
be between 1 and 99 wt % of the mixture of extraction agent stream
and coal tar stream in the treatment zone. The extraction can be
performed at a temperature between 0.degree. C. and 250.degree. C.
When the extraction agent contains a supercritical component, the
temperature is that required for the supercritical conditions of
the chosen supercritical component.
[0023] The extraction agent and the product are separated. The
extraction agent can be recycled, if desired. At least one
contaminant 63 is removed from the fraction 60. The contaminant(s)
can then be recovered and sent for additional treatment, if needed
(not shown).
[0024] The extraction agent can be one or more of amphiphilic block
copolymers, inclusion complexes of poly(methyl methacrylate) and
polycyclic aromatic hydrocarbons, cyclodextrins, functionalized
cyclodextrins, and cyclodextrin-functionalized polymers.
[0025] Cyclodextrins (CDs) are cyclic oligosaccharides. They have a
characteristic toroidal shape that form well defined cavities. The
cavities are typically about 8 .ANG. deep and have a diameter of
about 5 to 10 nm depending on the number of the glucose units. The
outside of the cavity is hydrophilic because of the presence of
hydroxyl groups, while the inner cavity is hydrophobic because of
presence of carbon and hydrogen atoms. CDs can accommodate guest
molecules in the cavity. Typically, the less polar part of the
guest molecule is in the cavity, and the more polar part is
outside. The hydroxyls on the outside of the CDs can be
functionalized, and functionalized CDs can be polymerized. Ionic
liquids can be used to functionalize CDs. CDs can be functionalized
to modify their properties and/or to introduce groups with specific
activity. Functionalization can involve one or more hydroxyl
groups.
[0026] CDs, functionalized CDs, and CD-functionalized polymers are
described in Ondo et al., Interaction of Ionic Liquids Ions with
Natural Cyclodextrins, J. Phys. Chem. B, 2011, 115, 10285-10297; He
et al., Interaction of Ionic Liquids Ions and .beta.-Cyclodextrin,
J. Phys. Chem. B, 2009, 113, 231-238; Mahlambi et al.,
"Polymerization of Cyclodextrin-Ionic Liquid Complexes for the
Removal of Organic and Inorganic Contaminants from Water," InTech
2011, 115-150, www.intechopen.com; Rogalski et al.,
Physico-Chemical Properties and Phase Behavior of the Ionic
Liquid-.beta.-Cyclodextrin Complexes, Int. J. Mol. Sci. 2013, 14,
16638-16655; Zheng et al., The Enhanced Dissolution of
.beta.-Cyclodextrin in Some Hydrophilic Ionic Liquids, J. Phys.
Chem. A, 2010, 114, 3926-3931; Uemasu, Effect of Methanol-Water
Mixture Solvent on Concentration of Indole in Coal Tar Using
.alpha.-Cyclodextrin as Complexing Agent, Sekiyu Gakkaishi, 34,
(4), 371-374 (1991); each of which is incorporated herein by
reference.
[0027] Inclusion complexes of polymethyl methacrylate and
polycyclic aromatic hydrocarbons can also be used as extraction
agents. Syndiotactic polymethyl methacrylate can form a helical
cavity in which polycyclic aromatic hydrocarbons are contained.
Formation of inclusion complexes is described in Kawauchi et al.,
Formation of the Inclusion Complex of Helical Syndiotactic
Poly(methyl methacrylate) and Polycyclic Aromatic Hydrocarbons,
Macromolecules, 2011, 44, 3452-3457, which is incorporated herein
by reference.
[0028] Amphiphilic block copolymers have alternating hydrophilic
polymer blocks and hydrophobic polymer blocks. The amphiphilic
block copolymer comprises at least two blocks selected from
polyethylene oxide (EO) blocks, polypropylene oxide (PO) blocks,
butylene oxide (BO) blocks, silicone (SC) blocks, urethane (UO)
blocks, polyurethane ionomer (PI) blocks, acrylate ionomer (AI)
blocks, polymethylacryate (MA) blocks, polyacrylic acid (AA)
blocks, and polyvinylidene chloride (VC) blocks. Examples of
suitable amphiphilic block copolymers include, but are not limited
to, EO-PO, EO-PO-EO, PO-EO-PO, EO-BO, PI-EO, AI-EO, SI-EO, and the
like. There are typically two or three different blocks in the
block copolymers.
[0029] Amphiphilic block copolymers are described in
Tungittiplakorn et al., "Engineered Polymeric Nanoparticles for
Soil Remediation," Environ. Sci. Technol. 2004, 38, 1605-1610;
Tungittiplakorn et al., "Engineered Polymeric Nanoparticles for
Bioremediation of Hydrophobic Contaminants," Environ. Sci. Technol.
2005, 39, 1354-1358; Qiao et al, "Stabilized Micelles of Amphoteric
Polyurethane Formed by Thermoresponsive Micellization in HCl
Aqueous Solution," Langmuir, 2008, 24, 3122-3126; Velasquez et al.,
Poly(vinylidene chloride)-Based Amphiphilic Block Copolymers,
Macromolecules, 2013, 46, 664-673; and U.S. Publication Nos.
2013/0030131, 2008/0045687, each of which is incorporated herein by
reference.
[0030] The CDs, functionalized CDs, CD-functionalized polymers,
inclusion complexes of poly(methyl methacrylate) and polycyclic
aromatic hydrocarbons, and amphiphilic block copolymer can
optionally be dissolved in ionic liquids, supercritical fluids, or
both. Alternatively, they can be used without an ionic liquid, or
supercritical fluid, if desired.
[0031] Ionic liquids are non-aqueous, organic salts composed of
ions where the positive ion is charge balanced with a negative ion.
These materials have low melting points, often below 100.degree.
C., undetectable vapor pressure, and good chemical and thermal
stability. The cationic charge of the salt is localized over hetero
atoms, such as nitrogen, phosphorous, sulfur, arsenic, boron,
antimony, and aluminum, and the anions may be any inorganic,
organic, or organometallic species. Suitable ionic liquids include,
but are not limited to, imidazolium-based ionic liquids,
pyrrolidinium-based ionic liquids, pyridinium-based ionic liquids,
sulphonium-based ionic liquids, phosphonium-based ionic liquids,
and ammonium-based ionic liquids, and combinations thereof
[0032] Supercritical fluids are substances at a temperature and
pressure above the critical point, where distinct liquid and gas
phases do not exist. They have properties of both liquids and
vapors. Suitable supercritical fluids include, but are not limited
to, supercritical carbon dioxide, supercritical ammonia,
supercritical ethane, supercritical propane, supercritical butane,
and supercritical water, and combinations thereof. In some
embodiments, the gas fraction from the separation zone can be used
as the source of the carbon dioxide or ammonia for the
supercritical carbon dioxide or supercritical ammonia.
[0033] Alternatively, the fraction 60 is sent to treatment zone 61
and contacted with an adsorbent. The adsorption is typically
performed at temperatures between about 0.degree. C. and about
150.degree. C. In one embodiment, after the adsorbent bed is fully
loaded to capacity, a desorbent is introduced into the bed, and the
contaminant is then recovered from the desorbent/contaminant
mixture. Alternatively, the bed can be heated to remove the
adsorbed contaminant. In some embodiments, the coal tar stream is
piped to another adsorbent bed during desorption of the first
bed.
[0034] The adsorbent comprises exfoliated graphite oxide, thermally
exfoliated graphite oxide or intercalated graphite compounds.
Exfoliated graphite oxide, thermally exfoliated graphite oxide, and
intercalated graphite compounds are described in Hristea et al.,
Characterization of Exfoliated Graphite for Heavy Oil Sorption, J.
Thermal Anal. And calorimetry, Vol. 91 (2008) 3, 817-823; Tryba et
al., Influence of chemically prepared H.sub.2SO.sub.4-graphite
intercalation compound (GIC) precursor on parameters of exfoliated
graphite (EG) for oil sorption from water, Carbon, 41 (2002)
2009-2025; Tryba et al., Exfoliated graphite as a New Sorbent for
Removal of Engine Oils from Wastewater, Spill Science and Tech.
Bull., Vol. 8, Nos. 5-6, 569-571; Toyoda et al., Heavy oil sorption
using exfoliated graphite New application of exfoliated graphite to
protect heavy oil pollution, Carbon, 38 (2000) 199-210; and U.S.
Pat. No. 7,658,901, each of which is incorporated herein by
reference.
[0035] The contaminants from the extraction or adsorption process
include, but are not limited to, nitrogen heterocyclic aromatics,
oxygen heterocyclic aromatics, and sulfur heterocyclic aromatics
and combinations thereof.
[0036] In some embodiments, at least two contaminants are removed
from the fraction 60. The first product can be removed using a
first extraction agent or adsorbent, and then the second product
can removed using a second extraction agent or adsorbent.
[0037] As shown, the contaminants are removed from fraction 60. As
will be understood by those of skill in the art, the treatment zone
61 can be located in various positions along the process depending
on the impact of the particular contaminant on the product or
process, as discussed above with respect to the optional
contaminant removal zone 35. The treatment zone 61 could be located
before, after, or in place of, the optional contaminant removal
zone 35, before or after the separation zone 45, or before or after
the hydrocarbon conversion zone 75, as well as in other suitable
locations. When the treatment zone 61 is located after the
separation zone 45 as illustrated, a portion of the coal tar stream
is treated (fraction 60 as illustrated). When the treatment zone 61
is located before the separation zone 45, all or a portion of the
coal tar stream 30 could be treated.
[0038] The treated fraction 64 can be sent to one or more
hydrocarbon conversion zones. For example, the treated fraction can
be sent to hydrocarbon conversion zone 75 for hydrocracking, for
example, to produce product 85. Suitable hydrocarbon conversion
zones include, but are not limited to, hydrotreating zones,
hydrocracking zones fluid catalytic cracking zones, alkylation
zones, transalkylation zones, oxidation zones and hydrogenation
zones.
[0039] Hydrotreating is a process in which hydrogen gas is
contacted with a hydrocarbon stream in the presence of suitable
catalysts which are primarily active for the removal of
heteroatoms, such as sulfur, nitrogen, oxygen, and metals from the
hydrocarbon feedstock. In hydrotreating, hydrocarbons with double
and triple bonds may be saturated. Aromatics may also be saturated.
Typical hydrotreating reaction conditions include a temperature of
about 290.degree. C. (550.degree. F.) to about 455.degree. C.
(850.degree. F.), a pressure of about 3.4 MPa (500 psig) to about
27.6 MPa (4000 psig), a liquid hourly space velocity of about 0.5
hr.sup.-1 to about 4 hr.sup.-1, and a hydrogen rate of about 168 to
about 1,011 Nm.sup.3/m.sup.3 oil (1,000-6,000 scf/bbl). Typical
hydrotreating catalysts include at least one Group VIII metal,
preferably iron, cobalt and nickel, and at least one Group VI
metal, preferably molybdenum and tungsten, on a high surface area
support material, preferably alumina Other typical hydrotreating
catalysts include zeolitic catalysts, as well as noble metal
catalysts where the noble metal is selected from palladium and
platinum.
[0040] Hydrocracking is a process in which hydrocarbons crack in
the presence of hydrogen to lower molecular weight hydrocarbons.
Typical hydrocracking conditions may include a temperature of about
290.degree. C. (550.degree. F.) to about 468.degree. C.
(875.degree. F.), a pressure of about 3.5 MPa (500 psig) to about
20.7 MPa (3000 psig), a liquid hourly space velocity (LHSV) of
about 1.0 to less than about 2.5 hr.sup.-1, and a hydrogen rate of
about 421 to about 2,527 Nm.sup.3/m.sup.3 oil (2,500-15,000
scf/bbl). Typical hydrocracking catalysts include amorphous
silica-alumina bases or low-level zeolite bases combined with one
or more Group VIII or Group VIB metal hydrogenating components, or
a crystalline zeolite cracking base upon which is deposited a Group
VIII metal hydrogenating component. Additional hydrogenating
components may be selected from Group VIB for incorporation with
the zeolite base.
[0041] Fluid catalytic cracking (FCC) is a catalytic hydrocarbon
conversion process accomplished by contacting heavier hydrocarbons
in a fluidized reaction zone with a catalytic particulate material.
The reaction in catalytic cracking is carried out in the absence of
substantial added hydrogen or the consumption of hydrogen. The
process typically employs a powdered catalyst having the particles
suspended in a rising flow of feed hydrocarbons to form a fluidized
bed. In representative processes, cracking takes place in a riser,
which is a vertical or upward sloped pipe. Typically, a pre-heated
feed is sprayed into the base of the riser via feed nozzles where
it contacts hot fluidized catalyst and is vaporized on contact with
the catalyst, and the cracking occurs converting the high molecular
weight oil into lighter components including liquefied petroleum
gas (LPG), gasoline, and a distillate. The catalyst-feed mixture
flows upward through the riser for a short period (a few seconds),
and then the mixture is separated in cyclones. The hydrocarbons are
directed to a fractionator for separation into LPG, gasoline,
diesel, kerosene, jet fuel, and other possible fractions. While
going through the riser, the cracking catalyst is deactivated
because the process is accompanied by formation of coke which
deposits on the catalyst particles. Contaminated catalyst is
separated from the cracked hydrocarbon vapors and is further
treated with steam to remove hydrocarbon remaining in the pores of
the catalyst. The catalyst is then directed into a regenerator
where the coke is burned off the surface of the catalyst particles,
thus restoring the catalyst's activity and providing the necessary
heat for the next reaction cycle. The process of cracking is
endothermic. The regenerated catalyst is then used in the new
cycle. Typical FCC conditions include a temperature of about
400.degree. C. to about 800.degree. C., a pressure of about 0 to
about 688 kPa g (about 0 to 100 psig), and contact times of about
0.1 seconds to about 1 hour. The conditions are determined based on
the hydrocarbon feedstock being cracked, and the cracked products
desired. Zeolite-based catalysts are commonly used in FCC reactors,
as are composite catalysts which contain zeolites, silica-aluminas,
alumina, and other binders.
[0042] Transalkylation is a chemical reaction resulting in transfer
of an alkyl group from one organic compound to another. Catalysts,
particularly zeolite catalysts, are often used to effect the
reaction. If desired, the transalkylation catalyst may be metal
stabilized using a noble metal or base metal, and may contain
suitable binder or matrix material such as inorganic oxides and
other suitable materials. In a transalkylation process, a
polyalkylaromatic hydrocarbon feed and an aromatic hydrocarbon feed
are provided to a transalkylation reaction zone. The feed is
usually heated to reaction temperature and then passed through a
reaction zone, which may comprise one or more individual reactors.
Passage of the combined feed through the reaction zone produces an
effluent stream comprising unconverted feed and product
monoalkylated hydrocarbons. This effluent is normally cooled and
passed to a stripping column in which substantially all C5 and
lighter hydrocarbons present in the effluent are concentrated into
an overhead stream and removed from the process. An aromatics-rich
stream is recovered as net stripper bottoms, which is referred to
as the transalkylation effluent.
[0043] The transalkylation reaction can be effected in contact with
a catalytic composite in any conventional or otherwise convenient
manner and may comprise a batch or continuous type of operation,
with a continuous operation being preferred. The transalkylation
catalyst is usefully disposed as a fixed bed in a reaction zone of
a vertical tubular reactor, with the alkylaromatic feed stock
charged through the bed in an upflow or downflow manner. The
transalkylation zone normally operates at conditions including a
temperature in the range of about 130.degree. C. to about
540.degree. C. The transalkylation zone is typically operated at
moderately elevated pressures broadly ranging from about 100 kPa to
about 10 MPa absolute. The transalkylation reaction can be effected
over a wide range of space velocities. That is, volume of charge
per volume of catalyst per hour, weight hourly space velocity
(WHSV), is generally in the range of from about 0.1 to about 30
hr.sup.-1. The catalyst is typically selected to have relatively
high stability at a high activity level.
[0044] Alkylation is typically used to combine light olefins, for
example mixtures of alkenes such as propylene and butylene, with
isobutane to produce a relatively high-octane branched-chain
paraffinic hydrocarbon fuel, including isoheptane and isooctane.
Similarly, an alkylation reaction can be performed using an
aromatic compound such as benzene in place of the isobutane. When
using benzene, the product resulting from the alkylation reaction
is an alkylbenzene (e.g. toluene, xylenes, ethylbenzene, etc.). For
isobutane alkylation, typically, the reactants are mixed in the
presence of a strong acid catalyst, such as sulfuric acid or
hydrofluoric acid. The alkylation reaction is carried out at mild
temperatures, and is typically a two-phase reaction. Because the
reaction is exothermic, cooling is needed. Depending on the
catalyst used, normal refinery cooling water provides sufficient
cooling. Alternatively, a chilled cooling medium can be provided to
cool the reaction. The catalyst protonates the alkenes to produce
reactive carbocations which alkylate the isobutane reactant, thus
forming branched chain paraffins from isobutane. Aromatic
alkylation is generally now conducted with solid acid catalysts
including zeolites or amorphous silica-aluminas.
[0045] The alkylation reaction zone is maintained at a pressure
sufficient to maintain the reactants in liquid phase. For a
hydrofluoric acid catalyst, a general range of operating pressures
is from about 200 to about 7100 kPa absolute. The temperature range
covered by this set of conditions is from about -20.degree. C. to
about 200.degree. C. For at least alkylation of aromatic compounds,
the volumetric ratio of hydrofluoric acid to the total amount of
hydrocarbons entering the reactor should be maintained within the
broad range of from about 0.2:1 to about 10:1, preferably from
about 0.5:1 to about 2:1
[0046] In some processes, all or a portion of the coal feed 10 is
mixed with oxygen 95 and steam 100 and reacted under heat and
pressure in the gasification zone 20 to form syngas 105, which is a
mixture of carbon monoxide and hydrogen. The syngas 105 can be
further processed using the Fischer-Tropsch reaction to produce
gasoline or using the water-gas shift reaction to produce more
hydrogen.
[0047] Oxidation involves the oxidation of hydrocarbons to
oxygen-containing compounds, such as aldehydes. The hydrocarbons
include alkanes, alkenes, typically with carbon numbers from 2 to
15, and alkyl aromatics, Linear, branched, and cyclic alkanes and
alkenes can be used. Oxygenates that are not fully oxidized to
ketones or carboxylic acids can also be subjected to oxidation
processes, as well as sulfur compounds that contain --S--H
moieties, thiophene rings, and sulfone groups. The process is
carried out by placing an oxidation catalyst in a reaction zone and
contacting the feed stream which contains the desired hydrocarbons
with the catalyst in the presence of oxygen. The type of reactor
which can be used is any type well known in the art such as
fixed-bed, moving-bed, multi-tube, CS IR, fluidized bed, etc. The
feed stream can be flowed over the catalyst bed either up-flow or
down-flow in the liquid, vapor, or mixed phase. In the case of a
fluidized-bed, the feed stream can be flowed co-current or
counter-current. In a CSTR the feed stream can be continuously
added or added batch-wise. The feed stream contains the desired
oxidizable species along with oxygen. Oxygen can be introduced
either as pure oxygen or as air, or as liquid phase oxidants
including hydrogen peroxide, organic peroxides, or peroxy-acids.
The molar ratio of oxygen (O.sub.2) to substrate to be oxidized can
range from about 5:1 to about 1:10. In addition to oxygen and
alkane or alkene, the feed stream can also contain a diluent gas
selected form nitrogen, neon, argon, helium, carbon dioxide, steam
or mixtures thereof As stated, the oxygen can be added as air which
could also provide a diluent. The molar ratio of diluent gas to
oxygen ranges from greater than zero to about 10:1. The catalyst
and feed stream are reacted at oxidation conditions which include a
temperature of about 25.degree. C. to about 600.degree. C., a
pressure of about 101 kPa to about 5,066 kPa and a space velocity
of about 100 to about 100,000 hr.sup.-1.
[0048] Hydrogenation involves the addition of hydrogen to
hydrogenatable hydrocarbon compounds. Alternatively hydrogen can be
provided in a hydrogen-containing compound with ready available
hydrogen, such as tetralin, alcohols, hydrogenated naphthalenes,
and others via a transfer hydrogenation process with or without a
catalyst. The hydrogenatable hydrocarbon compounds are introduced
into a hydrogenation zone and contacted with a hydrogen-rich
gaseous phase and a hydrogenation catalyst in order to hydrogenate
at least a portion of the hydrogenatable hydrocarbon compounds. The
catalytic hydrogenation zone may contain a fixed, ebulated or
fluidized catalyst bed. Alternatively the hydrogenation process can
be carried out in the liquid phase in a CSTR. This reaction zone is
typically at a pressure from about 689 k Pa gauge (100 psig) to
about 13790 k Pa gauge (2000 psig) with a maximum catalyst bed
temperature in the range of about 177.degree. C. (350.degree. F.)
to about 454.degree. C. (850.degree. F.). The liquid hourly space
velocity is typically in the range from about 0.2 hr.sup.-1 to
about 10 hr.sup.-1 and hydrogen circulation rates from about 200
standard cubic feet per barrel (SCFB) (35.6 m.sup.3 /m.sup.3) to
about 10,000 SCFB (1778 m.sup.3/m.sup.3).
[0049] While at least one exemplary embodiment has been presented
in the foregoing detailed description of the invention, it should
be appreciated that a vast number of variations exist. It should
also be appreciated that the exemplary embodiment or exemplary
embodiments are only examples, and are not intended to limit the
scope, applicability, or configuration of the invention in any way.
Rather, the foregoing detailed description will provide those
skilled in the art with a convenient road map for implementing an
exemplary embodiment of the invention. It being understood that
various changes may be made in the function and arrangement of
elements described in an exemplary embodiment without departing
from the scope of the invention as set forth in the appended
claims.
* * * * *
References