Production of Olefins and Aromatics

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° C. to 1000° C. or a reverse flow reactor operating at a temperature of 900° C. to 1,700° C. and is thermally cracked to produce one or more hydrocarbon effluent fractions.

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Description
FIELD OF THE INVENTION

The invention relates to the production of olefins and aromatics.

BACKGROUND OF THE INVENTION

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.

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.

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° C. to 650° 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 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° 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

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.

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.

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.

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° C. to 700° C.

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, CO2, and H2O. 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.

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, CO2, and H2O. Conversion to acetylene is net endothermic. The acetylene can subsequently be converted to olefins, aromatics and other valuable chemicals.

SUMMARY OF THE INVENTION

In one aspect, the invention resides in 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° C. to 1000° C. and recovering one or more hydrocarbon effluent fractions.

In a further aspect, the invention resides in 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 biomass 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° C. to 1000° C. and recovering one or more hydrocarbon effluent fractions.

Conveniently, the residence time of the feed at said temperature of 600° C. to 1000° 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.

Conveniently, the hydrocarbon effluent fractions comprise C2+ olefins and C6+ aromatic hydrocarbons. Generally, the process further comprises removing CO, CO2, H2O, and organic oxygenates from said hydrocarbon effluent fractions.

In yet a further aspect, the invention resides in 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° C. to 1,700° 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.

In still yet a further aspect, the invention resides in 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.

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.

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

FIG. 1 is a schematic diagram of a process of upgrading a biomass pyrolysis-oil employing a steam cracker.

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

As used herein, the term “Cn” 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 “Cn+” 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 “Cn−” 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.

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° F. (343° C.), and is referred to as 650° F.+ (343° C.+) resid. Vacuum resid is the bottoms product from a column under vacuum where the heaviest distilled product is nominally 1050° F. (566° C.), and is referred to as 1050° F.+ (566° C.+) 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° F. or at most +/−100° F.) The term “resid” as used herein means the 650° F.+ (343° C.+) resid and 1050° F.+ (566° C.+) resid unless otherwise specified (note that 650° F.+ resid comprises 1050° F.+ resid).

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.

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.

As discussed above, when biomass is pyrolyzed at temperatures of about 450° C. to about 650° 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.

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.

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.

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° C. to 1000° 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 C2+ olefins and C6+ aromatic hydrocarbons, while the oxygen present is rejected as CO, CO2, H2O, 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.

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° C. to about 500° 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.

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° C. to 1,700° 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, CO2, and H2O. The resultant acetylene can readily be converted by hydrogenation, oligomerization and aromatization to olefins and aromatics.

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.

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.

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.

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.

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.

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° C. and 260° C. in the first tube bank 2, while the feed may be heated in the second tube bank to temperatures between 315° C. and 540° 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° C. to 705° C., while the tubes of the radiant section 40 may further expose the vapor phase to temperatures between 600° C. and 1000° C. Further, the temperature of the recycled stream via line 30 may be at temperatures between 260° C. to 315° C.

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.

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° C., preferably in excess of 1500° C., more preferably in excess of 1700° 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.

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.

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, CO2 and/or H2O may be removed via the removal components 217.

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.

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, CO2 and/or H2O 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.

In operation, the biomass pyrolysis-oil feed is typically heated to a temperature in the range of 100° C. and 500° 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° C. to 1700° C., preferably in the range of 1400° C. to 1700° C., which convert the pyrolysis oil to acetylene and other hydrocarbons, with the oxygen present again being rejected as CO, CO2, H2O, and organic oxygenates. The residence time of the reactor feed above 500° 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° C. to 500° C., and may be cooled to temperatures in the range of 150° C. to 400° C.

In another embodiment, this invention relates to:

  • 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° C. to 1000° C. and recovering one or more hydrocarbon effluent fractions.
  • 2. The process of paragraph 1, wherein the residence time of the feed at said temperature of 600° C. to 1000° C. is less than 1 second.
  • 3. The process of paragraph 1 or 2, wherein the feed to the steam cracking unit also comprises a fossil hydrocarbon feedstock.
  • 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.
  • 5. The process of any of paragraphs 1 to 4, wherein the hydrocarbon effluent fractions comprise C2+ olefins and C6+ aromatic hydrocarbons.
  • 6. The process of any of paragraphs 1 to 5 further comprising removing CO, CO2, H2O, 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° C. to 1000° C. and recovering one or more hydrocarbon effluent fractions.

  • 8. The process of paragraph 7, wherein said condensable vapor is supplied to the steam cracking unit without intermediate liquefaction.
  • 9. The process of paragraph 7 or 8, wherein the residence time of the feed at said temperature of 600° C. to 1000° C. is less than 1 second.
  • 10. The process of paragraph 7, 8, or 9, wherein the feed to the steam cracking unit also comprises a fossil hydrocarbon feedstock.
  • 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.
  • 12. The process of any of paragraphs 7 to 11, wherein the hydrocarbon effluent fractions comprise C4− olefins and C6+ aromatic hydrocarbons.
  • 13. The process of any of paragraphs 7 to 12 further comprising removing CO, CO2, H2O, 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° C. to 1,700° 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 paragraph 14, wherein the residence time of the feed at a temperature above 500° 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 paragraph 16, wherein the thermal cracking zone of (c) is a steam cracker pyrolysis furnace.
  • 18. The process of paragraph 16, wherein the thermal cracking zone of (c) is a reverse flow reactor.
  • 19. The process of paragraph 16, 17, or 18, wherein a fossil hydrocarbon feedstock is co-fed to the heating zone of (a).
  • 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).
  • 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).
  • 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

Estimated yields for the process of FIG. 1 were calculated for a biomass pyrolysis-oil having the following composition:

    • Water content of 20 wt %
    • pH of 2.2
    • Density of 1.207 kg/l at 15° C.
    • Higher heating value of 17.57 MJ/kg
    • Lower heating value of 15.83 MJ/kg
    • Carbon content of 43.2 wt %
    • Hydrogen content of 7.7 wt %
    • Oxygen content of 48.8 wt %.

For an estimated biomass pyrolysis-oil feed rate of 347 kta, the following yield estimates were calculated:

    • 13 kTA bttms (line 22)
    • Contained within line 43
      • 99 kTA CO
      • 79 kTA CO2
      • 56 kTA produced H2O (i.e., produced from biomass pyrolysis-oil, not including dilution steam added to the process)
      • 100 kTA hydrocarbon; with the following composition of the hydrocarbon fraction
        • 10 wt % fuel gas
        • 19 wt % ethylene
        • 12 wt % propylene
        • 10 wt % C4's
        • 6 wt % C5's
        • 4 wt % benzene
        • 17 wt % C6-C10 excluding benzene
        • 21 wt % C10+ hydrocarbons.

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° C. to 1000° 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° C. to 1000° 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 C2+ olefins and C6+ aromatic hydrocarbons.

6. The process of claim 1, further comprising removing CO, CO2, H2O, 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° C. to 1000° 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° C. to 1000° 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 C4− olefins and C6+ aromatic hydrocarbons.

13. The process of claim 7, further comprising removing CO, CO2, H2O, 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° C. to 1,700° 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° 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.

Patent History
Publication number: 20130296619
Type: Application
Filed: May 7, 2012
Publication Date: Nov 7, 2013
Inventors: LARRY L. IACCINO (SEABROOK, TX), SURBHI JAIN (HOUSTON, TX), GARY D. MOHR (HOUSTON, TX)
Application Number: 13/465,707
Classifications
Current U.S. Class: Production Of Hydrocarbon Mixture From Refuse Or Vegetation (585/240)
International Classification: C10G 1/00 (20060101);