U.S. patent application number 13/465707 was filed with the patent office on 2013-11-07 for production of olefins and aromatics.
The applicant listed for this patent is LARRY L. IACCINO, SURBHI JAIN, GARY D. MOHR. Invention is credited to LARRY L. IACCINO, SURBHI JAIN, GARY D. MOHR.
Application Number | 20130296619 13/465707 |
Document ID | / |
Family ID | 49513057 |
Filed Date | 2013-11-07 |
United States Patent
Application |
20130296619 |
Kind Code |
A1 |
IACCINO; LARRY L. ; et
al. |
November 7, 2013 |
Production of Olefins and Aromatics
Abstract
In a process for producing olefins and aromatic hydrocarbons, a
feed comprising a biomass pyrolysis oil or a fraction thereof is
supplied to a steam cracking unit operating at a temperature of
600.degree. C. to 1000.degree. C. or a reverse flow reactor
operating at a temperature of 900.degree. C. to 1,700.degree. C.
and is thermally cracked to produce one or more hydrocarbon
effluent fractions.
Inventors: |
IACCINO; LARRY L.;
(SEABROOK, TX) ; JAIN; SURBHI; (HOUSTON, TX)
; MOHR; GARY D.; (HOUSTON, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
IACCINO; LARRY L.
JAIN; SURBHI
MOHR; GARY D. |
SEABROOK
HOUSTON
HOUSTON |
TX
TX
TX |
US
US
US |
|
|
Family ID: |
49513057 |
Appl. No.: |
13/465707 |
Filed: |
May 7, 2012 |
Current U.S.
Class: |
585/240 |
Current CPC
Class: |
C10G 1/02 20130101; C10G
2400/20 20130101; C10G 9/36 20130101; C10G 2400/30 20130101; C10G
3/40 20130101; C10G 1/06 20130101 |
Class at
Publication: |
585/240 |
International
Class: |
C10G 1/00 20060101
C10G001/00 |
Claims
1. A process for producing olefins and aromatic hydrocarbons, the
process comprising: (a) supplying a feed comprising a biomass
pyrolysis-oil or a fraction thereof to a steam cracking unit
operating at a temperature of 600.degree. C. to 1000.degree. C. and
recovering one or more hydrocarbon effluent fractions.
2. The process of claim 1, wherein the residence time of the feed
at said temperature of 600.degree. C. to 1000.degree. C. is less
than 1 second.
3. The process of claim 1, wherein the feed to the steam cracking
unit also comprises a fossil hydrocarbon feedstock.
4. The process of claim 3, wherein the fossil hydrocarbon feedstock
is selected from ethane, natural gas liquids, natural gas
condensate, naphtha, distillate, gas oils, resids, shale oils
and/or crude oils.
5. The process of claim 1, wherein the hydrocarbon effluent
fractions comprise C.sub.2+ olefins and C.sub.6+ aromatic
hydrocarbons.
6. The process of claim 1, further comprising removing CO,
CO.sub.2, H.sub.2O, and organic oxygenates from said hydrocarbon
effluent fractions.
7. A process for producing olefins and aromatic hydrocarbons, the
process comprising: (a) pyrolysing biomass in a reactor under
conditions to convert the biomass to a vapor condensable into
pyrolysis oil, non-condensable gases and solid biochar; and (b)
supplying a feed comprising at least part of the condensable vapor
or the condensed pyrolysis oil to a steam cracking unit operating
at a temperature of 600.degree. C. to 1000.degree. C. and
recovering one or more hydrocarbon effluent fractions.
8. The process of claim 7, wherein said condensable vapor is
supplied to the steam cracking unit without intermediate
liquefaction.
9. The process of claim 7, wherein the residence time of the feed
at said temperature of 600.degree. C. to 1000.degree. C. is less
than 1 second.
10. The process of claim 7, wherein the feed to the steam cracking
unit also comprises a fossil hydrocarbon feedstock.
11. The process of claim 10, wherein the fossil hydrocarbon
feedstock stream is selected from ethane, natural gas liquids,
natural gas condensate, naphtha, distillate, gas oils, resids,
shale oils, and/or crude oils.
12. The process of claim 7, wherein the hydrocarbon effluent
fractions comprise C.sub.4- olefins and C.sub.6+ aromatic
hydrocarbons.
13. The process of claim 7, further comprising removing CO,
CO.sub.2, H.sub.2O, and organic oxygenates from said hydrocarbon
effluent fractions.
14. A process for producing olefins and aromatic hydrocarbons, the
process comprising: (a) supplying a feed comprising a biomass
pyrolysis oil or a fraction thereof to a reverse flow reactor
operating at a temperature of 900.degree. C. to 1,700.degree. C.
and recovering one or more hydrocarbon effluent fractions including
acetylene; and (b) converting at least a portion of the acetylene
to olefins and/or aromatics.
15. The process of claim 14, wherein the residence time of the feed
at a temperature above 500.degree. C. is less than 1 second.
16. A process for producing olefins and aromatic hydrocarbons, the
process comprising: (a) supplying a feed comprising a biomass
pyrolysis oil or a fraction thereof along with steam to an initial
heating zone at a temperature sufficient to vaporize a portion of
the biomass pyrolysis oil in the presence of the steam and produce
a two phase stream; (b) feeding the two phase stream of (a) to a
vapor-liquid separator to produce a vapor stream and a liquid
stream; and (c) feeding the vapor stream of (b) to a thermal
cracking zone to produce a product stream enriched in olefins and
aromatics.
17. The process of claim 16, wherein the thermal cracking zone of
(c) is a steam cracker pyrolysis furnace.
18. The process of claim 16, wherein the thermal cracking zone of
(c) is a reverse flow reactor.
19. The process of claim 16, wherein a fossil hydrocarbon feedstock
is co-fed to the heating zone of (a).
20. The process of claim 16, wherein a fossil hydrocarbon feedstock
is co-fed to the vapor-liquid separator of (b).
21. The process of claim 16, wherein a fossil hydrocarbon feedstock
is co-fed to the thermal cracking zone of (c).
22. The process of claim 16, wherein the liquid stream from the
vapor-liquid separator of (b) is sent to a fuel disposition.
Description
FIELD OF THE INVENTION
[0001] The invention relates to the production of olefins and
aromatics.
BACKGROUND OF THE INVENTION
[0002] There is a desire in the industry to be able to produce
commodity organic chemicals, particularly olefins and aromatics,
from renewable feedstocks. Some are pursuing ethanol dehydration to
ethylene but the competitiveness of this approach is questionable
since ethanol currently has a higher value as a transportation
fuel. Similarly bio-derived fats and oils (including algal oils)
that could be used as commodity chemical feedstocks are challenged
if they have a disposition into transportation fuels or foods.
[0003] Raw biomass (crop residue, wood waste, municipal waste) is a
much cheaper feed, but these relatively low density, solid
materials are expensive to handle and transport to a large scale
facility for production of commodity chemicals.
[0004] Raw biomass can be converted via fast pyrolysis to a more
easily transportable liquid called biomass pyrolysis-oil. During
pyrolysis, the biomass is heated to moderate temperatures
(450.degree. C. to 650.degree. C.) in the absence of any externally
supplied oxygen. The vapors formed on heating of the biomass
condense quickly to provide biomass pyrolysis-oil as a liquid.
Biomass pyrolysis-oil is a complex mixture of various compounds
including water, guaiacols, catechols, syringols, vanillins,
furancarboxaldehydes, and carboxylic acids including acetic acid,
formic acid, and other carboxylic acids. A representative
comparison of composition and physical properties of biomass
pyrolysis-oil and heavy fuel oil is depicted in Table 1, below
(reproduced from Czernik S. and Bridgewater A. V., "Overview of
Applications of Biomass Fast Pyrolysis Oil", Energy & Fuels,
2004, 18, pp. 590-598).
TABLE-US-00001 TABLE 1 Biomass Pyrolysis-Oil Heavy Fuel Oil
Physical Property Moisture content (wt %) 15-30 0.1 pH 2-3 N/A
Specific gravity 1.2 0.94 Heat value (MJ/kg) 16-19 40 Viscosity at
50.degree. C. (cP) 40-100 180 Elemental Composition (wt %) C 54-58
85 H 5.5-7.0 11 O 35-40 1.0 N 0-0.2 0.3 Ash 0-0.2 0.1 Solids
content (wt %) 0.2-1 1 Distillation Residue (wt %) Up to 50 1
[0005] As will be seen from Table 1, the commercial use of biomass
pyrolysis-oil faces many challenges stemming mainly from the
presence of large amounts of oxygenated species in the oil, which
results in the oil having a low energy content and the oil being
corrosive and thermally unstable. Nevertheless, biomass
pyrolysis-oil is currently being produced commercially as a fuel
for boilers, kilns, etc. It has also been considered for upgrading
to transportation fuels via hydrotreating to remove the oxygen as
water but this is currently impractical due to high capital and
hydrogen costs.
[0006] U.S. Published Patent Application No. 2011/0232164 discloses
the use of biomass pyrolysis-oil as a co-feed for a heavy petroleum
oil coking process to improve the operation of the coking process
and to utilize biomaterial for the production of transportation
fuels. The coking process may be a delayed coking process or a
fluidized bed coking process.
[0007] U.S. Published Patent Application No. 2011/0232161 discloses
a process for the conversion of biomass pyrolysis-oil into
precursors for hydrocarbon transportation fuels which comprises
contacting liquid superheated water or supercritical water with the
biomass pyrolysis oil to depolymerize and deoxygenate the biomass
into the transportation fuel precursors.
[0008] U.S. Published Patent Application No. 2010/0222620 discloses
a process for fluid catalytic cracking of oxygenated hydrocarbon
compounds, comprising the step of contacting a reaction feed
comprising an oxygenated hydrocarbon compound, such as glycerol and
biomass pyrolysis-oil and optionally in combination with a
crude-oil derived material, such as VGO, with a fluid cracking
catalyst material during a contact time of less than 3 seconds, at
a temperature in the range of 300.degree. C. to 700.degree. C.
[0009] According to the present invention, it has now been found
that biomass pyrolysis-oil can be upgraded by being fed directly
(without hydrotreating) to a steam cracker, either alone or jointly
with a fossil hydrocarbon feedstock. Part of the biomass
pyrolysis-oil is converted to olefins, mainly ethylene and
propylene, and aromatics, while oxygen in the biomass pyrolysis-oil
is rejected as CO, CO.sub.2, and H.sub.2O. A heavy fraction is also
produced that can be used as a fuel for burners and furnaces. The
reaction is exothermic, whereas steam cracking of fossil
hydrocarbon feedstocks is endothermic. Thus, by supplying a mixed
biomass pyrolysis-oil/fossil hydrocarbon feedstock to the steam
cracker, the heat requirements for the operation can be
reduced.
[0010] Alternatively, the biomass pyrolysis-oil can be supplied to
a higher temperature, thermal conversion reactor, such as a reverse
flow reactor (RFR), where the majority hydrocarbon product is
acetylene while oxygen in the biomass pyrolysis-oil is rejected as
CO, CO.sub.2, and H.sub.2O. Conversion to acetylene is net
endothermic. The acetylene can subsequently be converted to
olefins, aromatics and other valuable chemicals.
SUMMARY OF THE INVENTION
[0011] In one aspect, the invention resides in a process for
producing olefins and aromatic hydrocarbons, the process
comprising:
[0012] (a) supplying a feed comprising a biomass pyrolysis-oil or a
fraction thereof to a steam cracking unit operating at a
temperature of 600.degree. C. to 1000.degree. C. and recovering one
or more hydrocarbon effluent fractions.
[0013] In a further aspect, the invention resides in a process for
producing olefins and aromatic hydrocarbons, the process
comprising:
[0014] (a) pyrolysing biomass in a reactor under conditions to
convert the biomass to a vapor condensable into biomass
pyrolysis-oil, non-condensable gases and solid biochar; and
[0015] (b) supplying a feed comprising at least part of the
condensable vapor or the condensed pyrolysis-oil to a steam
cracking unit operating at a temperature of 600.degree. C. to
1000.degree. C. and recovering one or more hydrocarbon effluent
fractions.
[0016] Conveniently, the residence time of the feed at said
temperature of 600.degree. C. to 1000.degree. C. is less than 1
second, typically less than 0.5 second, such as less than 0.25
second. In one embodiment, the feed to the steam cracking unit also
comprises a fossil hydrocarbon feedstock, such as ethane, natural
gas liquids, natural gas condensate, naphtha, distillate, gas oils,
resids, shale oils, and/or crude oils.
[0017] Conveniently, the hydrocarbon effluent fractions comprise
C.sub.2+ olefins and C.sub.6+ aromatic hydrocarbons. Generally, the
process further comprises removing CO, CO.sub.2, H.sub.2O, and
organic oxygenates from said hydrocarbon effluent fractions.
[0018] In yet a further aspect, the invention resides in a process
for producing olefins and aromatic hydrocarbons, the process
comprising:
[0019] (a) supplying a feed comprising a biomass pyrolysis-oil or a
fraction thereof to a reverse flow reactor operating at a
temperature of 900.degree. C. to 1,700.degree. C. and recovering
one or more hydrocarbon effluent fractions including acetylene;
and
[0020] (b) converting at least a portion of the acetylene to
olefins and/or aromatics.
[0021] In still yet a further aspect, the invention resides in a
process for producing olefins and aromatic hydrocarbons, the
process comprising:
[0022] (a) supplying a feed comprising a biomass pyrolysis-oil or a
fraction thereof along with steam to an initial heating zone at a
temperature sufficient to vaporize a portion of the biomass
pyrolysis oil in the presence of the steam and produce a two phase
stream;
[0023] (b) feeding the two phase stream of (a) to a vapor-liquid
separator to produce a vapor stream and a liquid stream; and
[0024] (c) feeding the vapor stream of (b) to a thermal cracking
zone to produce a product stream enriched in olefins and
aromatics.
[0025] Generally, the thermal cracking zone of (c) is a steam
cracker pyrolysis furnace or the thermal cracking zone of (c) is a
reverse flow reactor.
[0026] In one embodiment, a fossil hydrocarbon feedstock is co-fed
to the heating zone of (a) and/or the vapor-liquid separator of
(b).
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a schematic diagram of a process of upgrading a
biomass pyrolysis-oil employing a steam cracker.
[0028] FIG. 2 is a flow diagram of a process of upgrading a biomass
pyrolysis-oil employing a regenerative reverse flow reactor.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0029] As used herein, the term "C.sub.n" hydrocarbon wherein n is
a positive integer, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
means a hydrocarbon having n number of carbon atom(s) per molecule.
The term "C.sub.n+" hydrocarbon wherein n is a positive integer,
e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, as used herein, means
a hydrocarbon having at least n number of carbon atom(s) per
molecule. The term "C.sub.n-" hydrocarbon wherein n is a positive
integer, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, as used
herein, means a hydrocarbon having no more than n number of carbon
atom(s) per molecule.
[0030] As used herein "resid" refers to the complex mixture of
heavy petroleum compounds otherwise known in the art as residuum or
residual. Atmospheric resid is the bottoms product produced in
atmospheric distillation where the endpoint of the heaviest
distilled product is nominally 650.degree. F. (343.degree. C.), and
is referred to as 650.degree. F..sup.+ (343.degree. C..sup.+)
resid. Vacuum resid is the bottoms product from a column under
vacuum where the heaviest distilled product is nominally
1050.degree. F. (566.degree. C.), and is referred to as
1050.degree. F..sup.+ (566.degree. C..sup.+) resid. (The term
"nominally" means here that reasonable experts may disagree on the
exact cut point for these terms, but probably by no more than
+/-50.degree. F. or at most +/-100.degree. F.) The term "resid" as
used herein means the 650.degree. F..sup.+ (343.degree. C..sup.+)
resid and 1050.degree. F..sup.+ (566.degree. C..sup.+) resid unless
otherwise specified (note that 650.degree. F..sup.+ resid comprises
1050.degree. F..sup.+ resid).
[0031] As used herein, the term "fossil hydrocarbon feedstock"
refers to the class of feedstocks that are the result of biological
material being transformed over millions of years into gas, vapor,
and/or liquid. These are composed predominantly of hydrocarbons
although low levels of oxygen, sulfur, and nitrogen containing
species may also be present. Examples of fossil hydrocarbons
include crude oil, shale oil, natural gas condensates, natural gas
liquids, and natural gas. Fractions of these streams such as
methane, ethane, propane, butane, naphtha, distillate, gasoils, and
resids are also included with the scope of the term.
[0032] The term "biomass" is used herein in its conventionally
accepted sense as meaning the living and recently dead biological
material that can be converted for use as fuel or for industrial
production. The criterion as biomass is that the material should be
recently participating in the carbon cycle so that the release of
carbon in the combustion process results in no net increase
averaged over a reasonably short period of time (for this reason,
fossil fuels such as peat, lignite and coal are not considered
biomass by this definition as they contain carbon that has not
participated in the carbon cycle for a significant time so that
their combustion results in a net increase in atmospheric carbon
dioxide). Most commonly, biomass refers to plant matter grown for
use as biofuel, but it also includes plant or animal matter used
for production of fibers, chemicals or heat. Biomass may also
include biodegradable wastes that can be burnt as fuel including
municipal wastes, green waste (the biodegradable waste comprised of
garden or park waste such as grass or flower cuttings and hedge
trimmings), byproducts of farming including animal manures, food
processing wastes, sewage sludge, black liquor from wood pulp or
algae. It excludes organic material which has been transformed by
geological processes into substances such as coal, oil shale or
petroleum. Biomass is widely and typically grown from plants,
including miscanthus, spurge, sunflower, switchgrass, hemp, corn
(maize), poplar, willow and other trees, sugarcane, and oil palm
(palm oil) with the roots, stems, leaves, seed husks, and fruits
all being potentially useful.
[0033] As discussed above, when biomass is pyrolyzed at
temperatures of about 450.degree. C. to about 650.degree. C. it is
converted to a condensable vapor, non-condensable gases and solid
biochar. The term "biomass pyrolysis-oil" is used herein to mean
this condensable vapor and the condensed oil produced therefrom.
Such a material generally has the properties indicated in Table
1.
[0034] The term "fuel disposition" is intended to include use of a
composition as a fuel either neat or blended with other streams for
convenience or property modification (viscosity, density, BTU
value, etc) and encompass such final dispositions as a boiler fuel;
a furnace fuel, or a transportation fuel oil, as well as use in a
partial oxidation unit to produce fuel gas and/or synthesis gas and
use in a coker to produce lighter liquid fuels.
[0035] Described herein is a process which allows biomass
pyrolysis-oil or a fraction thereof to be upgraded to olefins and
aromatic hydrocarbons by thermal cracking without the need for
prior hydrotreating.
[0036] In one embodiment, upgrading of the biomass pyrolysis-oil or
fraction is effected in a steam cracker pyrolysis furnace operating
at a temperature of 600.degree. C. to 1000.degree. C. The pyrolysis
oil is supplied to the furnace either alone, or in combination with
a fossil hydrocarbon feedstock, generally under conditions that the
residence time of feed in the radiant section of furnace is less
than 1 second, typically less than 0.5 second, such as less than
0.25 second. Under these conditions, the biomass pyrolysis-oil is
converted to C.sub.2+ olefins and C.sub.6+ aromatic hydrocarbons,
while the oxygen present is rejected as CO, CO.sub.2, H.sub.2O, and
organic oxygenates. Thus, separating these oxygen-containing
species from the product effluent leaves a hydrocarbon mixture that
can be fractionated to produce a number of valuable chemical
feedstocks.
[0037] The biomass pyrolysis-oil can be supplied directly to the
pyrolysis furnace of the steam cracker or may initially be
supplied, alone or in combination with a fossil hydrocarbon
feedstock, to an initial heating zone of the steam cracker where
the biomass pyrolysis-oil is heated in the presence of steam to a
temperature, typically from 300.degree. C. to about 500.degree. C.,
sufficient to vaporize a portion of the biomass pyrolysis-oil and
produce a two phase stream. The two phase stream is then fed to a
vapor-liquid separator where the stream is divided into a vapor
phase stream and a liquid phase stream. The vapor phase stream is
then passed to the pyrolysis furnace of the steam cracker where it
is thermally cracked to produce a product stream enriched in
olefins and aromatics, while the liquid phase stream is typically
sent to a fuel disposition.
[0038] In another embodiment, upgrading of the biomass
pyrolysis-oil or fraction thereof is effected in a reverse flow
reactor operating at a temperature of 900.degree. C. to
1,700.degree. C. Again the biomass pyrolysis-oil can be supplied to
the furnace either alone, or in combination with a fossil
hydrocarbon feedstock, but in this case, under the extremely high
temperatures existing in the reactor, the biomass pyrolysis-oil is
converted to a hydrocarbon fraction composed mainly of acetylene,
with the oxygen present again being rejected as CO, CO.sub.2, and
H.sub.2O. The resultant acetylene can readily be converted by
hydrogenation, oligomerization and aromatization to olefins and
aromatics.
[0039] As in the steam cracking embodiment, the biomass
pyrolysis-oil and optionally a fossil hydrocarbon feedstock can be
supplied directly to the thermal cracking zone of the reverse flow
reactor or may be supplied to an initial heating zone of the
reactor where the biomass pyrolysis-oil is contacted with steam and
partially vaporized. A vapor phase stream can then be withdrawn by
a vapor-liquid separator for passage to the thermal cracking zone
of the reactor, while the liquid phase stream is removed for fuel
disposition.
[0040] Referring now to the drawings, FIG. 1 shows a first
embodiment of the invention where upgrading of biomass
pyrolysis-oil is effected in a steam cracker which includes a
furnace 1 having a convection section 3 and a radiant section 40.
The convection section 3 includes various convection section tube
banks (e.g., first tube bank 2, second tube bank 6, third tube bank
49 and fourth tube bank 23), which may use hot flue gases from the
radiant section of the furnace to heat fluids within the respective
tube banks.
[0041] Along the flow path through the furnace 1, a biomass
pyrolysis-oil feed may have other fluids added, such as steam
and/or a fossil hydrocarbon feedstock. For instance, the mixing can
be accomplished using any mixing device known within the art, such
as a first sparger 4 or second sparger 8 of a double sparger
assembly 9. In particular, a biomass pyrolysis-oil feed may pass
through a fluid valve 14 and primary dilution steam may be passed
via primary dilution line 17 through a primary dilution steam valve
15 to be mixed with the heated feed in the respective spargers 4 or
8 to form a mixed stream in lines 11 and 12, which pass through
controller 7. Also, a secondary dilution steam stream 18 can be
biomass pyrolysis-oil heated in the superheater section 16 of the
convection section, may be combined with water via water line 26
through an intermediate desuperheater 25 (e.g., control valve and
water atomizer nozzle), and mixed with the heated mixed stream.
Optionally, the secondary dilution steam stream 18 may be further
split into a flash steam stream in flash steam line 19, which is
mixed with the biomass pyrolysis-oil feed, and a bypass steam
stream in bypass line 21, which is mixed with the vapor phase from
the flash in line 13 before the vapor phase is cracked in line 24
in the radiant section 40. The flash steam stream may be combined
with the mixed stream to form a flash stream in flash line 20.
[0042] Along with the addition of certain fluids, certain portions
of the biomass pyrolysis-oil feed may be removed from the process
as well. For example, a separator vessel 5 (e.g., flash separator
vessel, as exemplified in U.S. Pat. Nos. 7,578,929; 7,488,459;
7,247,765; 7,193,123; and 7,312,371; which are each incorporated
herein) may be utilized to separate the flash stream 20 into two
phases: a vapor phase comprising predominantly volatile compounds
and steam and a liquid phase comprising predominantly non-volatile
compounds. The vapor phase is preferably removed from the separator
vessel 5 as an overhead vapor stream and is further processed in a
centrifugal separator 38, which removes trace amounts of entrained
and/or condensed liquid. The remainder of the vapor stream is
passed via overhead line 13, vapor phase control valve 36, and
crossover line 24 to the radiant section 40 for cracking (e.g.,
reactor feed). The liquid phase of the flashed mixture stream is
removed from a boot or cylinder 35 on the bottom of the separator
vessel 5 as a bottoms stream 27. This stream 27 may be further
processed in a pump 37 and cooler 28 with the cooled stream 29
being split into a recycle stream 30 and export stream 22.
[0043] Once the vapor stream is exposed to heat in the radiant
section 40, the reactor product or effluent may be further
processed. For instance, the process may include optional cooling
of the effluent from the radiant section 40 in one or more transfer
line heat exchangers, a primary fractionator, and a water quench
tower or indirect condenser. In this configuration, the effluent
may pass via line 41 to a transfer-line exchanger 42 to provide a
cooled effluent via quench line 43 for further processing. A
utility fluid, such as boiler feed water, may also pass through the
transfer-line exchanger 42 to steam drum 47 via lines 44 and 45.
The steam drum 47 may be coupled to the third tube bank 49 to
generate high pressure steam via lines 48, 50, 52 and 53 and a
utility supply line 46. A steam control valve may be coupled
between lines 50, 51 and 52 to provide a water source that controls
the temperature of the steam.
[0044] In operation, the biomass pyrolysis-oil feed will be heated
to different temperatures in different sections of the furnace. For
instance, the feed may be heated to temperatures between about
150.degree. C. and 260.degree. C. in the first tube bank 2, while
the feed may be heated in the second tube bank to temperatures
between 315.degree. C. and 540.degree. C., which is also the
temperature utilized in the separator vessel 5. The vapor phase
from the separator vessel 5 is further heated in fourth or lower
convection section tube bank 23 to temperatures between 425.degree.
C. to 705.degree. C., while the tubes of the radiant section 40 may
further expose the vapor phase to temperatures between 600.degree.
C. and 1000.degree. C. Further, the temperature of the recycled
stream via line 30 may be at temperatures between 260.degree. C. to
315.degree. C.
[0045] FIG. 2 shows a second embodiment of the invention where
upgrading of biomass pyrolysis oil is effected in a regenerative
reverse flow reactor system comprising a regenerative reverse flow
reactor 202, a separator vessel 223, and two heat exchangers 219
and 229. The regenerative reverse flow reactor 202 has reactor beds
204 and 206 along with one or more injection components 213, 215,
and 225, one or more removal components 217 and 227 and one or more
lines 212, 214, 218, 220, 222, 224, 228, and 230 providing fluid
flow paths through the system. These components manage the flow of
various streams (e.g., reactor feeds, combustion feeds, combustion
products and reaction products) through the system. Further, the
separator vessel 223 and heat exchangers 219 and 229 may be similar
to the transfer line exchanger 42 and separator vessel 5 of FIG.
1.
[0046] The system may employ any suitable regenerative reverse flow
reactor 202, such as that described in U.S. Published Patent
Application No. 2007/0191664, the entire contents of which are
incorporated herein by reference. The reactor beds 204 and 206 are
located in reaction zone 208 and are effective in storing and
transferring heat to carry out chemical reactions and to produce
products, such as acetylene. These beds 204 and 206 may include
glass or ceramic beads or spheres, metal beads or spheres, ceramic
(including alumina, zirconia and/or yttria) or metal honeycomb
materials, ceramic tubes, extruded monoliths, and the like,
provided they are able to maintain integrity, functionality, and
withstand long term exposure to temperatures in excess of
1200.degree. C., preferably in excess of 1500.degree. C., more
preferably in excess of 1700.degree. C. within reaction zone 208.
The reactor bed(s) 204 and 206 may provide separate channels for
the combustion feeds, such as a fuel stream and a combustion
oxidant stream, to isolate the streams until they are combined
within the reaction zone 208. The combustion oxidant stream is an
oxygen-containing gas, generally air.
[0047] The injection components 213, 215, and 225 and removal
components 217 and 227 may include one or more valves, reactor
heads, manifolds, spargers, tubes and manifolds and other
components. Specifically, the injection components 213, 215, and
225 may include injection valves and an injection manifold for each
of the different feeds being provided to the reactor 202.
Similarly, the removal components 217 and 227 may include one or
more removal valves and removal manifolds.
[0048] Operation of the regenerative reverse flow reactor 202
involves different stages that follow a specific sequence to
generate a cycle. In particular, each cycle generally includes a
pyrolysis stage and combustion stage. The combustion stage begins
with the injection of combustion streams, such as a fuel, via line
212 and fuel injection manifold 213 and an oxidant via line 214 and
oxidant injection manifold 215. The combustion streams may be
introduced at a first end of the reaction zone 208 and then pass
through the second reactor bed 206 to the first reactor zone 204.
The combustion streams react exothermically in the reaction zone
208 to heat the reactor beds 204, 206 before exiting the reaction
zone 208 through the combustion removal line 218 via the combustion
removal component 217 at a second, opposite end of the reaction
zone 208. Based on the flow of the combustion stream, the
temperature gradient may reach a peak in the reaction zone 208 near
and in a portion of the first reactor bed 204, as the combustion
products move across the reactor bed 204 in the direction toward
the combustion removal component 217. The fuel and oxidant may be
maintained as separate streams to further control the location of
the exothermic reaction in the reaction zone 208. Regardless, the
combustion products that include CO, CO.sub.2 and/or H.sub.2O may
be removed via the removal components 217.
[0049] The pyrolysis stage begins with the injection of the biomass
pyrolysis-oil feed via line 224 and feed injection components 225
at the second end of the reaction zone 208. The biomass
pyrolysis-oil passes through the first reactor bed 204 and reacts
endothermically using the heat stored in the reactor bed 204. The
reaction effluent includes the reacted products, such as acetylene,
and unreacted feed and is subsequently cooled as it passes through
the second reactor bed 206 to the product removal line 228 via the
product removal component 227.
[0050] To manage the different streams supplied to and removed from
the reactor 202, various equipment, such as heat exchangers 219 and
229 and a separator vessel 223, may be utilized as part of this
process. The combustion products that include CO, CO.sub.2 and/or
H.sub.2O may be removed via the removal components 217 and provided
to the combustion heat exchanger 219 for recovery of heat. That is,
the combustion products may be cooled by passing water or the
biomass pyrolysis-oil feed at a lower temperature on the utility
side of the heat exchanger. Similarly, the biomass pyrolysis-oil
feed may be provided via line 222 to the separator vessel 223 that
separates a liquid bottoms fraction from the hydrocarbon stream
from the feed. The bottoms product may be further processed into
fuel or other products, while the remaining vapor fraction of the
feed may be provided directly to the feed injection component 225
or passed through the heat exchanger 219 to heat the reactor feed
prior to the feed injection component 225. The vapor fraction may
be provided alone, or combined with an oxidant stream or hydrogen
containing stream, to form the reactor feed. The reaction product
is removed from reaction zone 208 via the product removal
components 227, and may be provided to the product heat exchanger
229 for recovery of heat therefrom. That is, the reactor products
may be cooled by passing water, fuel or oxidant at a lower
temperature on the utility side of the heat exchanger 229.
[0051] In operation, the biomass pyrolysis-oil feed is typically
heated to a temperature in the range of 100.degree. C. and
500.degree. C. prior to the separator vessel 223. The initial
heating may be performed in combustion heat exchanger 219, which
utilizes the heat from the combustion products to heat the biomass
pyrolysis-oil feed, or may be performed in another unit, such as a
furnace or boiler. Also, the process may involve passing the vapor
product from the separator vessel 223 through the combustion heat
exchanger 219 to further heat the vapor phase from the combustion
products prior to the reactor 202. Regardless, the heated vapor
stream (e.g., the reactor feed) is provided to the reactor and
passes through the feed injection component 225 and first reactor
bed 204. In the reaction zone 208, the feed is exposed to
temperatures in the range of 900.degree. C. to 1700.degree. C.,
preferably in the range of 1400.degree. C. to 1700.degree. C.,
which convert the pyrolysis oil to acetylene and other
hydrocarbons, with the oxygen present again being rejected as CO,
CO.sub.2, H.sub.2O, and organic oxygenates. The residence time of
the reactor feed above 500.degree. C. is generally less than 1
second, for example less than 0.5 second, such as less than 0.25
second. Then, the reactor product is passed through the second
reactor bed 206 to the product removal component 227 and the heat
exchanger 229. The reactor product may be provided to the heat
exchanger 229 at temperatures in the range of 250.degree. C. to
500.degree. C., and may be cooled to temperatures in the range of
150.degree. C. to 400.degree. C.
[0052] In another embodiment, this invention relates to: [0053] 1.
A process for producing olefins and aromatic hydrocarbons, the
process comprising: [0054] (a) supplying a feed comprising a
biomass pyrolysis-oil or a fraction thereof to a steam cracking
unit operating at a temperature of 600.degree. C. to 1000.degree.
C. and recovering one or more hydrocarbon effluent fractions.
[0055] 2. The process of paragraph 1, wherein the residence time of
the feed at said temperature of 600.degree. C. to 1000.degree. C.
is less than 1 second. [0056] 3. The process of paragraph 1 or 2,
wherein the feed to the steam cracking unit also comprises a fossil
hydrocarbon feedstock. [0057] 4. The process of paragraph 3,
wherein the fossil hydrocarbon feedstock is selected from ethane,
natural gas liquids, natural gas condensate, naphtha, distillate,
gas oils, resid, shale oils and/or crude oils. [0058] 5. The
process of any of paragraphs 1 to 4, wherein the hydrocarbon
effluent fractions comprise C.sub.2+ olefins and C.sub.6+ aromatic
hydrocarbons. [0059] 6. The process of any of paragraphs 1 to 5
further comprising removing CO, CO.sub.2, H.sub.2O, and organic
oxygenates from said hydrocarbon effluent fractions. [0060] 7. A
process for producing olefins and aromatic hydrocarbons, the
process comprising: [0061] (a) pyrolysing biomass in a reactor
under conditions to convert the biomass to a vapor condensable into
pyrolysis oil, non-condensable gases and solid biochar; and
[0062] (b) supplying a feed comprising at least part of the
condensable vapor or the condensed pyrolysis oil to a steam
cracking unit operating at a temperature of 600.degree. C. to
1000.degree. C. and recovering one or more hydrocarbon effluent
fractions. [0063] 8. The process of paragraph 7, wherein said
condensable vapor is supplied to the steam cracking unit without
intermediate liquefaction. [0064] 9. The process of paragraph 7 or
8, wherein the residence time of the feed at said temperature of
600.degree. C. to 1000.degree. C. is less than 1 second. [0065] 10.
The process of paragraph 7, 8, or 9, wherein the feed to the steam
cracking unit also comprises a fossil hydrocarbon feedstock. [0066]
11. The process of paragraph 10, wherein the fossil hydrocarbon
feedstock stream is selected from ethane, natural gas liquids,
natural gas condensate, naphtha, distillate, gas oils, resids,
shale oils, and/or crude oils. [0067] 12. The process of any of
paragraphs 7 to 11, wherein the hydrocarbon effluent fractions
comprise C.sub.4- olefins and C.sub.6+ aromatic hydrocarbons.
[0068] 13. The process of any of paragraphs 7 to 12 further
comprising removing CO, CO.sub.2, H.sub.2O, and organic oxygenates
from said hydrocarbon effluent fractions. [0069] 14. A process for
producing olefins and aromatic hydrocarbons, the process
comprising: [0070] (a) supplying a feed comprising a biomass
pyrolysis oil or a fraction thereof to a reverse flow reactor
operating at a temperature of 900.degree. C. to 1,700.degree. C.
and recovering one or more hydrocarbon effluent fractions including
acetylene; and [0071] (b) converting at least a portion of the
acetylene to olefins and/or aromatics. [0072] 15. The process of
paragraph 14, wherein the residence time of the feed at a
temperature above 500.degree. C. is less than 1 second. [0073] 16.
A process for producing olefins and aromatic hydrocarbons, the
process comprising: [0074] (a) supplying a feed comprising a
biomass pyrolysis oil or a fraction thereof along with steam to an
initial heating zone at a temperature sufficient to vaporize a
portion of the biomass pyrolysis oil in the presence of the steam
and produce a two phase stream; [0075] (b) feeding the two phase
stream of (a) to a vapor-liquid separator to produce a vapor stream
and a liquid stream; and [0076] (c) feeding the vapor stream of (b)
to a thermal cracking zone to produce a product stream enriched in
olefins and aromatics. [0077] 17. The process of paragraph 16,
wherein the thermal cracking zone of (c) is a steam cracker
pyrolysis furnace. [0078] 18. The process of paragraph 16, wherein
the thermal cracking zone of (c) is a reverse flow reactor. [0079]
19. The process of paragraph 16, 17, or 18, wherein a fossil
hydrocarbon feedstock is co-fed to the heating zone of (a). [0080]
20. The process of any of paragraphs 16 to 19, wherein a fossil
hydrocarbon feedstock is co-fed to the vapor-liquid separator of
(b). [0081] 21. The process of any of paragraphs 16 to 20, wherein
a fossil hydrocarbon feedstock is co-fed to the thermal cracking
zone of (c). [0082] 22. The process of any of paragraphs 16 to 21,
wherein the liquid stream from the vapor-liquid separator of (b) is
sent to a fuel disposition.
EXAMPLE 1
[0083] Estimated yields for the process of FIG. 1 were calculated
for a biomass pyrolysis-oil having the following composition:
[0084] Water content of 20 wt % [0085] pH of 2.2 [0086] Density of
1.207 kg/l at 15.degree. C. [0087] Higher heating value of 17.57
MJ/kg [0088] Lower heating value of 15.83 MJ/kg [0089] Carbon
content of 43.2 wt % [0090] Hydrogen content of 7.7 wt % [0091]
Oxygen content of 48.8 wt %.
[0092] For an estimated biomass pyrolysis-oil feed rate of 347 kta,
the following yield estimates were calculated: [0093] 13 kTA bttms
(line 22) [0094] Contained within line 43 [0095] 99 kTA CO [0096]
79 kTA CO.sub.2 [0097] 56 kTA produced H.sub.2O (i.e., produced
from biomass pyrolysis-oil, not including dilution steam added to
the process) [0098] 100 kTA hydrocarbon; with the following
composition of the hydrocarbon fraction [0099] 10 wt % fuel gas
[0100] 19 wt % ethylene [0101] 12 wt % propylene [0102] 10 wt %
C4's [0103] 6 wt % C5's [0104] 4 wt % benzene [0105] 17 wt % C6-C10
excluding benzene [0106] 21 wt % C10+ hydrocarbons.
* * * * *