US20170022425A1

US20170022425A1 - Staged catalyst loading for pyrolysis oil hydrodeoxygenation

Info

Publication number: US20170022425A1
Application number: US15/217,845
Authority: US
Inventors: Lance A. Baird; Andrew J. Towarnicky
Original assignee: UOP LLC
Current assignee: Honeywell UOP LLC
Priority date: 2015-07-24
Filing date: 2016-07-22
Publication date: 2017-01-26

Abstract

A method for deoxygenating a biomass-derived pyrolysis oil is described. The method includes combining a biomass-derived pyrolysis oil stream with a heated low-oxygen-py-oil diluent recycle stream to form a heated diluted py-oil feed stream that has a temperature of about 150° C. or greater. The heated diluted py-oil feed stream is contacted with a first deoxygenating catalyst in a first bed of a reactor to form a low-oxygen biomass-derived pyrolysis oil. The low-oxygen biomass-derived pyrolysis oil is contacted with a hydrocracking catalyst in a second bed of the reactor to form a hydrocracked low-oxygen biomass-derived pyrolysis oil effluent. A portion of the hydrocracked low-oxygen biomass-derived pyrolysis oil effluent comprises the heated low-oxygen biomass-derived py-oil diluent recycle stream.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Provisional Application No. 62/196,354 filed Jul. 24, 2015, the contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

Fast pyrolysis is a process during which organic carbonaceous biomass feedstock, i.e., “biomass”, such as wood waste, agricultural waste, algae, etc., is rapidly heated to between about 300° C. to about 900° C. in the absence of air using a pyrolysis reactor. Under these conditions, solid products, liquid products, and gaseous pyrolysis products are produced. A condensable portion (vapors) of the gaseous pyrolysis products is condensed into biomass-derived pyrolysis oil (commonly referred to as “py-oil”). Biomass-derived pyrolysis oil can be burned directly as fuel for certain boiler and furnace applications, and can also serve as a potential feedstock in catalytic processes for the production of fuels in petroleum refineries. Biomass-derived pyrolysis oil has the potential to replace up to 60% of transportation fuels, thereby reducing the dependency on conventional petroleum and reducing its environmental impact.
However, biomass-derived pyrolysis oil is a complex, highly oxygenated organic liquid having properties that currently limit its utilization as a biofuel. For example, biomass-derived pyrolysis oil has high acidity and a low energy density attributable in large part to oxygenated hydrocarbons in the oil, which can undergo secondary reactions during storage particularly if the oil is stored at elevated temperatures. “Oxygenated hydrocarbons” or “oxygenates” as used herein are organic compounds containing hydrogen, carbon, and oxygen. Such oxygenated hydrocarbons in the biomass-derived pyrolysis oil include carboxylic acids, phenols, cresols, alcohols, aldehydes, etc. Conventional biomass-derived pyrolysis oil comprises about 20% or greater by weight oxygen from these oxygenated hydrocarbons and about 20 to about 30% by weight water with high acidity (e.g., total acid number (TAN) greater than 100).
Conversion of biomass-derived pyrolysis oil into biofuels and chemicals requires full or partial deoxygenation of the biomass-derived pyrolysis oil. Such deoxygenation may proceed via two main routes, namely the elimination of either water or CO₂. Unfortunately, deoxygenating biomass-derived pyrolysis oil leads to rapid plugging or fouling of the processing catalyst in a hydroprocessing reactor caused by the formation of solids from the biomass-derived pyrolysis oil. Components in the pyrolysis oil form deposits on the processing catalysts causing catalytic bed fouling, reducing activity of the catalyst, and causing build up in the hydroprocessing reactor. It is believed that this plugging is due to an acid catalyzed polymerization of the various components of the biomass-derived pyrolysis oil, e.g., second order reactions in which the various components of the oil polymerize with themselves, that create either a glassy brown polymer or powdery brown char that limits run duration and processibility of the biomass-derived pyrolysis oil.
Accordingly, it is desirable to provide methods for producing a low-oxygen biomass-derived pyrolysis oil without plugging of the catalyst, thereby increasing run duration and improving processibility of the biomass-derived pyrolysis oil.

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE is an illustration of one embodiment of the process of the present invention.

SUMMARY OF THE INVENTION

One aspect of the invention is a method for deoxygenating a biomass-derived pyrolysis oil. In one embodiment, the method includes combining a biomass-derived pyrolysis oil stream with a heated low-oxygen-py-oil diluent recycle stream to form a heated diluted py-oil feed stream that has a temperature of about 150° C. or greater. The heated diluted py-oil feed stream is contacted with a first deoxygenating catalyst in a first bed of a reactor in the presence of hydrogen at first hydroprocessing conditions effective to form a low-oxygen biomass-derived pyrolysis oil. The low-oxygen biomass-derived pyrolysis oil is contacted with a hydrocracking catalyst in a second bed of the reactor in the presence of hydrogen at hydrocracking conditions effective to form a hydrocracked low-oxygen biomass-derived pyrolysis oil effluent. A portion of the hydrocracked low-oxygen biomass-derived pyrolysis oil effluent comprises the heated low-oxygen biomass-derived py-oil diluent recycle stream.

DETAILED DESCRIPTION OF THE INVENTION

As described in US Publication No. 2013/0152454, it was found that pyrolysis oil will polymerize to form a solid deposit at temperatures above about 100° C. in the absence of hydrotreating catalyst or in the presence of the catalyst when the temperature is also below the onset of hydrogenation reactions but above the onset of polymerization reactions. In addition, it was found that diluting the pyrolysis oil by recycling partially hydrogenated pyrolysis oil can prevent the formation of solids. The dilution is so effective that a fixed bed reactor may successfully be used instead of a slurry reactor.
However, it was later found that the recycled product liquid can still react to a lesser degree with the pyrolysis oil such that over time, the product liquid molecular weight and viscosity increase to such an extent that the pyrolysis oil—recycle liquid mixture can no longer be processed in a fixed bed reactor because the differential pressure across the reactor becomes too high.
Although not wishing to be bound by theory, it is believed that the reaction of substituted phenolic compounds in the recycled product liquid, such as cresol, with aldehydes in the pyrolysis oil feed leads to the increase in product molecular weight which ultimately limits the time on stream before the pressure differential across the reactor becomes too high.
In the present invention, in order to combat the pressure increase, at least two beds of catalyst are loaded in the hydrodeoxygenation reactor. A catalyst optimized for hydrodeoxygenation is loaded in the inlet zone, and a catalyst optimized for cracking is loaded in the outlet zone. Thus, the higher molecular weight compounds may be cracked back to lower molecular weight compounds in the second bed after the coupling reaction between phenolic and aldehyde compounds has taken place and after the reactive oxygenates have been reduced in the first bed.
The increase in molecular weight may thereby be limited, and the time on stream may be greatly increased. This results in a product which may be directly recycled instead of requiring fractionation. It may generate sufficient additional phenolic compounds to eliminate or reduce the need for make-up phenolics in the feed.
Two or more beds of catalyst are loaded in a reactor. The inlet bed of catalyst may be a noble metal such as Pt or Pd or non-noble metal such as Co—W, Ni—W, Ni—Mo, Co—Mo, Ni—Co—Mo, or variations on a refractory oxide support such as silica, alumina, silica-alumina, titania, or zirconia or other support such as carbon. The outlet bed of catalyst is a noble metal or non-noble metal deposited on a high acidity catalyst support such as silica-alumina, fluorided silica-alumina, zeolite, fluorided zeolite, rare-earth-doped zeolite, tungstated zirconia, sulfated zirconia or the like.
Various embodiments contemplated herein relate to methods for deoxygenating a biomass-derived pyrolysis oil to produce a low-oxygen biomass-derived pyrolysis oil effluent by contacting a heated diluted py-oil feed stream with a deoxygenating catalyst in the presence of hydrogen at hydroprocessing conditions to partially deoxygenate the heated diluted py-oil feed stream. It should be appreciated that while the deoxygenated oil produced are generally described herein as a “low-oxygen biomass-derived pyrolysis oil” or an “ultralow-oxygen biomass-derived pyrolysis oil,” these terms generally include any py-oil produced having a lower oxygen concentration (i.e., a lower residual oxygen content) than conventional biomass-derived pyrolysis oil. The term “low-oxygen biomass-derived pyrolysis oil” is py-oil having some oxygen, i.e., a biomass-derived pyrolysis oil in which a portion of the oxygenated hydrocarbons has been converted into hydrocarbons (i.e. a “hydrocarbon product”). In an exemplary embodiment, the low-oxygen biomass-derived pyrolysis oil comprises an organic phase (i.e., oil comprising primarily oxygenates and/or hydrocarbons) that comprises oxygen in an amount of from about 5 to about 25 weight percent (wt. %) of the organic phase. The term “ultralow-oxygen biomass-derived pyrolysis oil” is py-oil that has less oxygen than the low-oxygen biomass-derived pyrolysis oil and includes py-oil having substantially no oxygen, i.e., a biomass-derived pyrolysis oil in which substantially all the oxygenated hydrocarbons have been converted into hydrocarbons (i.e., a “hydrocarbon product”). In an exemplary embodiment, the ultralow-oxygen biomass-derived pyrolysis oil comprises an organic phase that comprises oxygen in an amount of from about 0 to about 1 wt. % of the organic phase. “Hydrocarbons” as used herein are organic compounds that contain principally only hydrogen and carbon, i.e., oxygen-free.
The heated diluted py-oil feed stream is formed by combining a biomass-derived pyrolysis oil stream with a heated low-oxygen-py-oil diluent recycle stream. The heated low-oxygen-py-oil diluent recycle stream is formed from a portion of the low-oxygen biomass-derived pyrolysis oil effluent that has been recycled and heated. Therefore, the heated low-oxygen-py-oil diluent recycle stream has already been partially deoxygenated, which removes not only some of the oxygen but also significantly reduces the amount of py-oil reactant components that can form solids by secondary polymerization reactions. As such, the heated low-oxygen-py-oil diluent recycle stream has less py-oil reactant components that can form solids and contains some oxygen but less oxygen than the biomass-derived pyrolysis oil stream. The inventors have found that by maintaining sufficient oxygen in the heated low-oxygen-py-oil diluent recycle stream, the biomass-derived pyrolysis oil stream is mutually miscible with the heated low-oxygen-py-oil diluent recycle stream.
In an exemplary embodiment, the biomass-derived pyrolysis oil stream has an initial temperature of about 100° C. or less, for example of about ambient, prior to being combined with the heated low-oxygen-py-oil diluent recycle stream to minimize formation of solids caused by secondary polymerization reactions in the py-oil before hydroprocessing, such as during storage. In an exemplary embodiment, the heated low-oxygen-py-oil diluent recycle stream has a recycle temperature of about 200° C. to about 450° C. By combining the biomass-derived pyrolysis oil stream with the heated low-oxygen-py-oil diluent recycle stream, the biomass-derived pyrolysis oil stream is diluted by the heated low-oxygen-py-oil diluent recycle stream and is rapidly heated, for example, to a temperature that is suitable for hydroprocessing. Moreover, diluting the biomass-derived pyrolysis oil stream with the mutually miscible heated diluent facilitates solubilizing any solids that may have formed during storage or that could otherwise form in the py-oil during subsequent hydroprocessing (e.g. glassy brown polymers or powdery brown char).
In an exemplary embodiment, the heated diluted py-oil feed stream is formed upstream from a hydroprocessing reactor that contains at least two catalyst beds.
The first bed contains the deoxygenating catalyst. The heated diluted py-oil feed stream is introduced to the hydroprocessing reactor operating at hydroprocessing conditions in the presence of hydrogen. Deoxygenation of the py-oil feed occurs producing the low-oxygen biomass-derived pyrolysis oil. In addition, it is believed that reactions take place between phenolic compounds and aldehyde compounds producing compounds having increased molecular weight.
The low-oxygen biomass-derived pyrolysis oil from the first bed is sent to the second bed of the hydroprocessing reactor. The second bed contains a hydrocracking catalyst which cracks higher molecular weight products back to lower molecular weight products.
In some embodiments, the deoxygenating catalyst bed can be divided into two or more beds containing deoxygenating catalyst. Similarly, the hydrocracking catalyst bed can be divided into two or more beds containing hydrocracking catalyst. Quench gas can be introduced between the beds to control the temperature rise in the beds.
Without being limited by theory, it is believed that by diluting the biomass-derived pyrolysis oil with the heated low-oxygen-py-oil diluent recycle stream, simple reactions of the biomass-derived pyrolysis oil with hydrogen to form a lower-oxygen biomass-derived pyrolysis oil are effectively increased and dominate while secondary polymerization reactions of biomass-derived pyrolysis oil components with themselves are reduced or minimized. By contacting products of that reaction with the hydrocracking catalyst, the oligomers formed in the first bed are cracked. Consequently, there is less fouling of the catalyst than with the deoxygenation alone, resulting in increased run duration and improved processability of the biomass-derived pyrolysis oil.
The Figure illustrates one embodiment of a process 100 for deoxygenating a biomass-derived pyrolysis oil. A biomass-derived pyrolysis oil stream 105 may be produced, from pyrolysis of biomass in a pyrolysis reactor, for example. Virtually any form of biomass can be used for pyrolysis to produce the biomass-derived pyrolysis oil. The biomass-derived pyrolysis oil may be derived from biomass material, such as, wood, agricultural waste, nuts and seeds, algae, forestry residues, and the like. The biomass-derived pyrolysis oil may be obtained by different modes of pyrolysis, such as, for example, fast pyrolysis, vacuum pyrolysis, catalytic pyrolysis, and slow pyrolysis or carbonization, and the like.
The composition of the biomass-derived pyrolysis oil can vary considerably and depends on the feedstock and processing variables. Examples of biomass-derived pyrolysis oil “as-produced” can contain up to about 1,000 to as much as about 20,000 ppm or more total metals, about 20 to about 33 weight percent (wt. %) of water that can have high acidity (e.g., TAN greater than 150), and a solids content of from about 0.1 wt. % to about 5 wt. %. The biomass-derived pyrolysis oil may be untreated (e.g., “as produced”). However, if needed, the biomass-derived pyrolysis oil can be selectively treated to reduce any or all of the above to a desired level. In an exemplary embodiment, the biomass-derived pyrolysis oil comprises an organic phase (i.e., oil comprising primarily oxygenates and/or hydrocarbons) that has a residual oxygen content of about 10 wt. % or greater, for example of about 20 wt. % or greater, for example from about 20 to about 40 wt. %, such as from about 20 to about 30 wt. % of the organic phase.
The biomass-derived pyrolysis oil can be thermally unstable and may be stored and/or handled so as to reduce its exposure to higher temperatures, minimizing any secondary polymerization reactions of the various components in the biomass-derived pyrolysis oil with themselves prior to hydroprocessing. In an exemplary embodiment, the biomass-derived pyrolysis oil stream 105 has as an initial temperature (e.g., storage temperature) of about 100° C. or less, or from about 0° C. to about 80° C., or from about 15° C. to about 50° C., or about ambient, to minimize secondary polymerization reactions.
The biomass-derived pyrolysis oil stream 105 is combined and diluted with a heated low-oxygen-py-oil diluent recycle stream 110 to form a heated diluted py-oil feed stream 115. The heated low-oxygen-py-oil diluent recycle stream 110 can be introduced to the biomass-derived pyrolysis oil stream 105 in a single stream together with a hydrogen-containing gas stream 120, or alternatively, the heated low-oxygen-py-oil diluent recycle stream 110 can be introduced to the biomass-derived pyrolysis oil stream 105 in a single or in multiple separate streams that do not include the hydrogen-containing gas stream 120. For example, the hydrogen-containing gas stream 125 can be introduced directly to the heated diluted py-oil feed stream 115 and/or the hydrogen-containing gas stream 130 can be introduced directly to the hydroprocessing reactor 135, and the heated diluted py-oil feed stream 115 can be introduced to the biomass-derived pyrolysis oil stream 105 absent the hydrogen-containing gas stream 120.
As will be discussed in further detail below, the heated low-oxygen-py-oil diluent recycle stream 110 is a py-oil stream that has been previously partially deoxygenated, recycled, and heated. As such, the heated low-oxygen-py-oil diluent recycle stream 110 has less py-oil reactant components that can form solids by secondary polymerization reactions, and contains some oxygen but less oxygen than the biomass-derived pyrolysis oil stream 105. By having some oxygen in the heated low-oxygen-py-oil diluent recycle stream 110, the biomass-derived pyrolysis oil stream 105 and the heated low-oxygen-py-oil diluent recycle stream 110 are mutually miscible. In an exemplary embodiment, the heated low-oxygen-py-oil diluent recycle stream 110 comprises a hydroprocessed organic phase that has a residual oxygen content of about 10 to about 25 wt. %, or about 12 to about 25 wt. % of the hydroprocessed organic phase. In one example, the hydroprocessed organic phase comprises oxygenates such as phenols, alkyl phenols, alcohols, ethers, and/or the like that are similar to and/or easily solubilized by the oxygenates contained in the biomass-derived pyrolysis oil stream 105.
In an exemplary embodiment, the heated low-oxygen-py-oil diluent recycle stream 110 has a temperature of from about 200° C. to about 450° C., or about 300° C. to about 450° C., or about 325° C. to about 425° C. In an exemplary embodiment, the biomass-derived pyrolysis oil stream 105 and the heated low-oxygen-py-oil diluent recycle stream 110 are combined at a predetermined recycle ratio that is defined by a mass flow rate of the heated low-oxygen-py-oil diluent recycle stream 110 to a mass flow rate of the biomass-derived pyrolysis oil stream 105 to form the heated diluted py-oil feed stream 115 that has a feed temperature of about 150° C. or greater, or about 150° C. to about 400° C., or about 180° C. to about 300° C. In an exemplary embodiment, the biomass-derived pyrolysis oil stream 105 is combined with the heated low-oxygen-py-oil diluent recycle stream 110 at the predetermined recycle ratio of about 1:1 to about 10:1.
The heated diluted py-oil feed stream 115 is introduced to the hydroprocessing reactor 135 along with a hydrogen-containing gas stream 130. The hydroprocessing reactor 135 can be a continuous flow reactor, such as a fixed-bed reactor, a continuous stirred tank reactor (CSTR), a trickle bed reactor, an ebulliating bed reactor, or any other reactor known to those skilled in the art for hydroprocessing.
The hydroprocessing reactor 135 has at least two beds 140A and 140B. The first bed 140A contains a deoxygenating catalyst in the presence of hydrogen. In an exemplary embodiment, the deoxygenating catalyst comprises a metal or a combination of metals, such as a base metal(s), a refractory metal(s), and/or a noble metal(s), such as platinum, palladium, ruthenium, nickel, molybdenum, tungsten, and/or cobalt. The metal(s) may be on a support, such as a carbon support, a silica support, an alumina support, a silica-alumina support, a gamma alumina support, and/or a titania support. Other hydroprocessing catalysts known to those skilled in the art may also be used.
The first bed 140A is operated at hydroprocessing conditions. In an exemplary embodiment, the hydroprocessing conditions include a reactor temperature of about 150° C. to about 400° C., about 150° C. to about 350° C., or about 180° C. to about 300° C., or about 180° C. to about 280° C., a reactor pressure of from about 2 to about 20 MPa gauge, or about 5.5 MPa (g) to about 13.8 MPa(g), a fresh feed weight hourly space velocity of about 0.05 hr⁻¹to about 1 hr⁻¹, and a hydrogen-containing gas treat rate of from about 1,000 to about 15,000 standard cubic feet per barrel (SCF/B).
In an exemplary embodiment, the heated diluted py-oil feed stream 115 is formed just upstream of the hydroprocessing reactor 135, and the feed temperature of the heated diluted py-oil feed stream 115 is at about the reactor temperature to facilitate rapid catalytic deoxygenation of the heated diluted py-oil feed stream 115 with a short or minimal residence time. The term “residence time” as used herein is the amount of time from when the biomass-derived pyrolysis oil stream 105 is combined with the heated low-oxygen-py-oil diluent recycle stream 110 to when the heated diluted py-oil feed stream 115 initially contacts the deoxygenating catalyst. By having a relatively short residence time, less solids can form in the heated diluted py-oil feed stream 115 at elevated temperatures by secondary polymerization reactions before hydroprocessing begins. In an exemplary embodiment, the residence time is about 60 seconds or less, for example about 20 seconds or less, for example about 10 second or less, such as from about 10 to about 1 seconds.
The heated diluted py-oil feed stream 115 contacts the deoxygenating catalyst at the hydroprocessing conditions in the presence of a hydrogen-containing gas stream 130 and forms a low-oxygen biomass-derived pyrolysis oil by converting a portion of the oxygenated hydrocarbons in the biomass-derived pyrolysis oil into hydrocarbons (i.e. partial deoxygenation). The heated diluted py-oil feed stream 115 can be mixed with the hydrogen-containing gas stream 130 in a distributor (not shown). In particular, hydrogen from the hydrogen-containing gas stream 130 (and/or 120 and/or 125) removes oxygen from the biomass-derived pyrolysis oil as water to produce the low-oxygen biomass-derived pyrolysis oil that comprises an aqueous phase and a hydroprocessed organic phase. The hydroprocessed organic phase comprises oil that is partially deoxygenated with some residual oxygenated hydrocarbons.
The low-oxygen biomass-derived pyrolysis oil is sent to the second bed 140B of the hydroprocessing reactor 135 which contains the hydrocracking catalyst. The hydrocracking catalyst can be any suitable hydrocracking catalyst, such as a noble metal or non-noble metal deposited on a high acidity catalyst support such as silica-alumina (fluoride or unfluorided), zeolite (fluoride or unfluorided), rare-earth-doped zeolite, tungstated zirconia, sulfated zirconia or the like.
Hydrogen-containing stream 145 can be introduced between the first and second beds 140A and 140B. It can be used to adjust the ratio of hydrogen to hydrocarbon in the second bed 140B and to adjust the temperature in the second bed 140B, as well as providing hydrogen for the cracking reaction. A distributor (not shown) can be used to mix the hydrogen-containing stream 145 and the low-oxygen biomass-derived pyrolysis oil from the first bed 140A.
In an exemplary embodiment, the hydrocracking conditions in the second bed 140B include a reactor temperature of about 150° C. to about 500° C., or about 150° C. to about 450° C., about 200° C. to about 450° C., or about 250° C. to about 450° C., a reactor pressure of from about 2 to about 20 MPa gauge, or about 12.4 MPa (g) to about 19.3 MPa(g), a weight hourly space velocity of about 0.1 hr⁻¹to about 3 hr⁻¹, and a hydrogen-containing gas treat rate of from about 1,000 to about 15,000 standard cubic feet per barrel (SCF/B).
In an exemplary embodiment, the hydroprocessed organic phase of the hydrocracked low-oxygen biomass-derived pyrolysis oil effluent 150 from the hydroprocessing reactor 135 has a residual oxygen content of from about 5 to about 25 wt. %, for example from about 7 to about 25 wt. %, such as from about 12 to about 25 wt. % of the hydroprocessed organic phase.
The benefits of catalytically deoxygenating and hydrocracking the biomass-derived pyrolysis oil that has been diluted with the heated low-oxygen-py-oil diluent recycle stream 110 include one or more of increasing hydrogen solubility, immolating the exotherm by dilution of the reactive species in the biomass-derived pyrolysis oil, reducing the reaction rate of bimolecular reactants that lead to secondary polymerization reactions, and cracking compounds which do undergo polymerization. This reduces or minimizes the formation of glassy brown polymers or powdery brown char on the catalysts.
In an exemplary embodiment, the hydrocracked low-oxygen biomass-derived pyrolysis oil effluent 150 is removed from the hydroprocessing reactor 135 and is passed through a cooler or condenser 155 to a separation zone 160. In an exemplary embodiment, the cooler 155 cools the hydrocracked low-oxygen biomass-derived pyrolysis oil effluent 150 to a temperature of about 30° C. to about 60° C. The separation zone 160 removes light volatiles, water, solids, and light liquids from the hydrocracked low-oxygen biomass-derived pyrolysis oil effluent 150 using one or more separation vessels, fractionation columns, heaters, condensers exchangers, pipes, pumps, compressors, controllers, and/or the like. The hydrocracked low-oxygen biomass-derived pyrolysis oil effluent 150 is introduced to the separation zone 160 and is separated into a water-H₂ gas containing stream 165, an aqueous stream 175, and a water-depleted low-oxygen py-oil stream 170.
The water-H₂ gas containing stream 165 is introduced to an aqueous-hydrogen gas separation and purification zone 180. In an exemplary embodiment, the water-H₂ gas containing stream 165 is cooled to a temperature of about 30° C. to about 60° C. The aqueous-hydrogen gas separation and purification zone 180 separates the water-H₂ gas containing stream 165 into an aqueous stream 185, a hydrogen-containing recycle gas stream 190, and a light volatiles stream 195.
Net gas stream 200 can be removed from the water-H₂ gas containing stream 165, and/or make-up hydrogen 205 can be added to the hydrogen-containing recycle gas stream 190 as needed.
The aqueous stream 175 comprises water and water-soluble organic compounds. The aqueous stream 175 may be sent to an organic recovery zone (not shown).
The water-depleted low-oxygen py-oil stream 170 is divided into a water-depleted low-oxygen py-oil intermediate stream 210 and a water-depleted low-oxygen py-oil recycle stream 215.
In some embodiments, the hydrogen-containing recycle gas stream 190 is introduced to the water-depleted low-oxygen py-oil recycle stream 215. In other embodiments, the hydrogen-containing recycle gas stream 190 can be introduced directly to the heated low-oxygen-py-oil diluent recycle stream 110, the heated diluted py-oil feed stream 115, and/or the first and/or second beds 140A and 140B of the hydroprocessing reactor 135.
The water-depleted low-oxygen py-oil recycle stream 215 is passed through a heater 220 to form the heated low-oxygen-py-oil diluent recycle stream 110. In an exemplary embodiment and as discussed above, the heater 220 heats the water-depleted low-oxygen py-oil recycle stream 215 to a temperature of about 200° C. to about 450° C.
The water-depleted low-oxygen py-oil intermediate stream 210 may be used, for example, as a fuel product, or alternatively, may be passed along for an additional hydroprocessing to further lower its oxygen content. As shown, the water-depleted low-oxygen py-oil intermediate stream 210 is combined with a hydrogen-containing gas stream 225 and introduced to a second hydroprocessing reactor 230. In an exemplary embodiment, the water-depleted low-oxygen py-oil intermediate stream 210 can be heated to a temperature of about 150° C. to about 400° C. in a heater (not shown) before being introduced into the second hydroprocessing reactor 230.
The second hydroprocessing reactor 230 can be, for example, a batch reactor or continuous flow reactor, such as a fixed-bed reactor, a continuous stirred tank reactor (CSTR), a trickle bed reactor, an ebullating bed reactor, a slurry reactor, or any other reactor known to those skilled in the art for hydroprocessing. The second hydroprocessing reactor 230 contains a deoxygenating catalyst in the presence of hydrogen as discussed above with respect to the deoxygenating catalyst in the hydroprocessing reactor 135. The second hydroprocessing reactor 230 is operating at hydroprocessing conditions. In an exemplary embodiment, the hydroprocessing conditions include a reactor temperature of from about 150° C. to about 400° C., such as from about 300° C. to about 375° C., a reactor pressure of from about 2 to about 20 MPa gauge, a weight hourly space velocity of about 0.1 hr⁻¹to about 2 hr⁻¹, and a hydrogen-containing gas treat rate of from about 1,000 to about 15,000 standard cubic feet per barrel (SCF/B). The deoxygenating catalyst in the second hydroprocessing reactor 230 can be the same as or different from the deoxygenating catalyst and the hydroprocessing reactor 135. In another embodiment, a noble metal catalyst can be used at a temperature of about 300° C. to about 520° C., a pressure of about 340 kPa(g) to about 5.5 MPa(g), as described in US 2016/0145172 A1, which is incorporated herein by reference.
In an exemplary embodiment, the water-depleted low-oxygen py-oil intermediate stream 210 contacts the deoxygenating catalyst at the hydroprocessing conditions in the presence of hydrogen-containing gas stream 225 to form an ultralow-oxygen biomass-derived pyrolysis oil effluent 235 by converting at least a portion of the oxygenated hydrocarbons in the low-oxygen biomass-derived pyrolysis oil into hydrocarbons. In particular, hydrogen from the hydrogen-containing gas stream 225 removes oxygen from the low-oxygen biomass-derived pyrolysis oil as water to produce the ultralow-oxygen biomass-derived pyrolysis oil effluent 235. The oil contained in the ultralow-oxygen biomass-derived pyrolysis oil effluent 235 may be partially deoxygenated with some residual oxygenated hydrocarbons, or may be substantially fully deoxygenated where substantially all of the oxygenated hydrocarbons are converted into hydrocarbons. In an exemplary embodiment, the ultralow-oxygen biomass-derived pyrolysis oil effluent 235 comprises a hydroprocessed organic phase that has a residual oxygen content of about 1 wt. % or less, for example from about 1 to about 0 wt. %, such as about 0.1 to about 0 wt. % of the hydroprocessed organic phase.
The ultralow-oxygen biomass-derived pyrolysis oil effluent 235 is passed through the cooler or condenser 240 and is introduced to a second separation zone 245. In some embodiments, a reactor feed/effluent heat exchanger could be used. The second separation zone 245 removes light volatiles, water, solids, and light liquids from the ultralow-oxygen biomass-derived pyrolysis oil effluent 235 using one or more separation vessels, fractionation columns, heaters, condensers exchangers, pipes, pumps, compressors, controllers, and/or the like.
In an exemplary embodiment, the ultralow-oxygen biomass-derived pyrolysis oil effluent 235 is cooled to a temperature of from about 30° C. to about 60° C. The second separation zone 245 separates the ultralow-oxygen biomass-derived pyrolysis oil effluent 235 into a water-containing stream 250, a hydrogen-contaminant containing gas stream 255, and a hydrocarbon product stream 260 that may be passed along for further processing and/or to be used as a fuel product. The water-containing stream 250 can be sent to a water treatment zone (not shown). The hydrogen-contaminant containing gas stream 255 can be sent to a hydrogen gas separation and purification zone (not shown).
By the term “about,” we mean within 10% of the value, or within 5%, or within 1%.
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.

Specific Embodiments

While the following is described in conjunction with specific embodiments, it will be understood that this description is intended to illustrate and not limit the scope of the preceding description and the appended claims.
A first embodiment of the invention is a method for deoxygenating biomass-derived pyrolysis oil comprising combining a biomass-derived pyrolysis oil stream with a heated low-oxygen-py-oil diluent recycle stream to form a heated diluted py-oil feed stream that has a temperature of about 150° C. or greater; contacting the heated diluted py-oil feed stream with a first deoxygenating catalyst in a first bed of a reactor in the presence of hydrogen at first hydroprocessing conditions effective to form a low-oxygen biomass-derived pyrolysis oil; and contacting the low-oxygen biomass-derived pyrolysis oil with a hydrocracking catalyst in a second bed of the reactor in the presence of hydrogen at hydrocracking conditions effective to form a hydrocracked low-oxygen biomass-derived pyrolysis oil effluent; wherein a portion of the hydrocracked low-oxygen biomass-derived pyrolysis oil effluent comprises the heated low-oxygen biomass-derived py-oil diluent recycle stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising introducing a hydrogen stream to the reactor between the first and second beds to adjust the ratio of hydrogen to hydrocarbon in the second bed and to adjust a temperature in the second bed. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein contacting the heated diluted py-oil feed stream comprises contacting the heated diluted py-oil feed stream with the first deoxygenating catalyst at the first hydroprocessing conditions that include a reaction temperature of from about 150° C. to about 400° C. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein contacting the low-oxygen biomass-derived pyrolysis oil comprises contacting the low-oxygen biomass-derived pyrolysis oil with the hydrocracking catalyst at the hydrocracking conditions that include a reaction temperature of from about 150° C. to about 500° C. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein contacting the heated diluted py-oil feed stream comprises partially deoxygenating the heated diluted py-oil feed stream to form the low-oxygen biomass-derived pyrolysis oil that comprises a hydroprocessed organic phase that has a residual oxygen content of from about 5 to about 25 wt % of the hydroprocessed organic phase. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the heated low-oxygen-py-oil diluent recycle stream has a residual oxygen content of from about 10 to about 25 wt % of the hydroprocessed organic phase. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the step of combining comprises forming the heated diluted py-oil feed stream at the feed temperature of from about 150° C. to about 400° C. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the step of combining comprises introducing the heated low-oxygen-py-oil diluent recycle stream to the biomass-derived pyrolysis oil stream that has a temperature of from about 0° C. to about 100° C. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the step of combining comprises introducing the heated low-oxygen-py-oil diluent recycle stream that has a temperature of from about 200° C. to about 450° C. to the biomass-derived pyrolysis oil stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the step of combining comprises combining the biomass-derived pyrolysis oil stream with the heated low-oxygen-py-oil diluent recycle stream at a predetermined recycle ratio of from about 1:1 to about 10:1, wherein the predetermined recycle ratio is defined by a recycle mass flow rate of the heated low-oxygen-py-oil diluent recycle stream to a py-oil mass flow rate of the biomass-derived pyrolysis oil stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the first hydroprocessing conditions or the hydrocracking conditions or both include a reactor pressure of about 2 to about 20 MPa (g). An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the first hydroprocessing conditions include a fresh feed weight hourly space velocity of the biomass-derived pyrolysis oil stream per volume of from about 0.1 hr⁻¹to about 2 hr⁻¹. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein contacting the heated diluted py-oil feed stream comprises contacting the heated diluted py-oil feed stream with the first deoxygenating catalyst by a residence time of about 60 sec or less, wherein the residence time is defined by a time from when the biomass-derived pyrolysis oil stream is combined with the heated low-oxygen-py-oil diluent recycle stream to when the heated diluted py-oil feed stream initially contacts the first deoxygenating catalyst. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising removing water from and separating the hydrocracked low-oxygen biomass-derived pyrolysis oil effluent to form a water-depleted low-oxygen py-oil recycle stream; and heating at least a portion of the water-depleted low-oxygen py-oil recycle stream to form at last a portion of the heated low-oxygen py-oil diluent recycle stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising removing water from and separating the hydrocracked low-oxygen biomass-derived pyrolysis oil effluent to form a water-depleted low-oxygen py-oil intermediate stream; and contacting the water-depleted low-oxygen py-oil intermediate stream with a second deoxygenating catalyst in the presence of hydrogen at second hydroprocessing conditions effective to form an ultralow-oxygen biomass-derived pyrolysis oil effluent.
A second embodiment of the invention is a method for deoxygenating a biomass-derived pyrolysis oil comprising combining a biomass-derived pyrolysis oil stream with a heated low-oxygen-py-oil diluent recycle stream to form a heated diluted py-oil feed stream that has a temperature of about 150° C. or greater; contacting the heated diluted py-oil feed stream with a first deoxygenating catalyst in a first bed of a reactor in the presence of hydrogen at first hydroprocessing conditions effective to form a low-oxygen biomass-derived pyrolysis oil; introducing a hydrogen stream to the reactor between the first bed and a second bed to adjust the ratio of hydrogen to hydrocarbon in the second bed and to adjust a temperature in the second bed; contacting the low-oxygen biomass-derived pyrolysis oil with a hydrocracking catalyst in a second bed of the reactor in the presence of hydrogen at hydrocracking conditions effective to form a hydrocracked low-oxygen biomass-derived pyrolysis oil effluent; wherein a portion of the hydrocracked low-oxygen biomass-derived pyrolysis oil effluent comprises the heated low-oxygen biomass-derived py-oil diluent recycle stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph wherein contacting the heated diluted py-oil feed stream comprises contacting the heated diluted py-oil feed stream with the first deoxygenating catalyst at the first hydroprocessing conditions that include a reaction temperature of from about 150° C. to about 400° C.; or wherein contacting the low-oxygen biomass-derived pyrolysis oil comprises contacting the low-oxygen biomass-derived pyrolysis oil with the hydrocracking catalyst at the hydrocracking conditions that include a reaction temperature of from about 150° C. to about 500-° C.; or both. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph wherein contacting the heated diluted py-oil feed stream comprises partially deoxygenating the heated diluted py-oil feed stream to form the low-oxygen biomass-derived pyrolysis oil that comprises a hydroprocessed organic phase that has a residual oxygen content of from about 5 to about 25 wt % of the hydroprocessed organic phase. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph wherein combining comprises combining the biomass-derived pyrolysis oil stream with the heated low-oxygen-py-oil diluent recycle stream at a predetermined recycle ratio of from about 1:1 to about 10:1, wherein the predetermined recycle ratio is defined by a recycle mass flow rate of the heated low-oxygen-py-oil diluent recycle stream to a py-oil mass flow rate of the biomass-derived pyrolysis oil stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising removing water from and separating the hydrocracked low-oxygen biomass-derived pyrolysis oil effluent to form a water-depleted low-oxygen py-oil intermediate stream; and contacting the water-depleted low-oxygen py-oil intermediate stream with a second deoxygenating catalyst in the presence of hydrogen at second hydroprocessing conditions effective to form an ultralow-oxygen biomass-derived pyrolysis oil effluent.
Without further elaboration, it is believed that using the preceding description that one skilled in the art can utilize the present invention to its fullest extent and easily ascertain the essential characteristics of this invention, without departing from the spirit and scope thereof, to make various changes and modifications of the invention and to adapt it to various usages and conditions. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limiting the remainder of the disclosure in any way whatsoever, and that it is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.
In the foregoing, all temperatures are set forth in degrees Celsius and, all parts and percentages are by weight, unless otherwise indicated.

Claims

1. A method for deoxygenating biomass-derived pyrolysis oil comprising:

combining a biomass-derived pyrolysis oil stream with a heated low-oxygen-py-oil diluent recycle stream to form a heated diluted py-oil feed stream that has a temperature of about 150° C. or greater;

contacting the heated diluted py-oil feed stream with a first deoxygenating catalyst in a first bed of a reactor in the presence of hydrogen at first hydroprocessing conditions effective to form a low-oxygen biomass-derived pyrolysis oil; and

contacting the low-oxygen biomass-derived pyrolysis oil with a hydrocracking catalyst in a second bed of the reactor in the presence of hydrogen at hydrocracking conditions effective to form a hydrocracked low-oxygen biomass-derived pyrolysis oil effluent;

wherein a portion of the hydrocracked low-oxygen biomass-derived pyrolysis oil effluent comprises the heated low-oxygen biomass-derived py-oil diluent recycle stream.

2. The method of claim 1 further comprising:

introducing a hydrogen stream to the reactor between the first and second beds to adjust the ratio of hydrogen to hydrocarbon in the second bed and to adjust a temperature in the second bed.

3. The method of claim 1 wherein contacting the heated diluted py-oil feed stream comprises contacting the heated diluted py-oil feed stream with the first deoxygenating catalyst at the first hydroprocessing conditions that include a reaction temperature of from about 150° C. to about 400° C.

4. The method of claim 1 wherein contacting the low-oxygen biomass-derived pyrolysis oil comprises contacting the low-oxygen biomass-derived pyrolysis oil with the hydrocracking catalyst at the hydrocracking conditions that include a reaction temperature of from about 150° C. to about 500° C.

5. The method of claim 1 wherein contacting the heated diluted py-oil feed stream comprises partially deoxygenating the heated diluted py-oil feed stream to form the low-oxygen biomass-derived pyrolysis oil that comprises a hydroprocessed organic phase that has a residual oxygen content of from about 5 to about 25 wt % of the hydroprocessed organic phase.

6. The method of claim 1 wherein the heated low-oxygen-py-oil diluent recycle stream has a residual oxygen content of from about 10 to about 25 wt % of the hydroprocessed organic phase.

7. The method of claim 1 wherein the step of combining comprises forming the heated diluted py-oil feed stream at the feed temperature of from about 150° C. to about 400° C.

8. The method of claim 1 wherein the step of combining comprises introducing the heated low-oxygen-py-oil diluent recycle stream to the biomass-derived pyrolysis oil stream that has a temperature of from about 0° C. to about 100° C.

9. The method of claim 1 wherein the step of combining comprises introducing the heated low-oxygen-py-oil diluent recycle stream that has a temperature of from about 200° C. to about 450° C. to the biomass-derived pyrolysis oil stream.

10. The method of claim 1 wherein the step of combining comprises combining the biomass-derived pyrolysis oil stream with the heated low-oxygen-py-oil diluent recycle stream at a predetermined recycle ratio of from about 1:1 to about 10:1, wherein the predetermined recycle ratio is defined by a recycle mass flow rate of the heated low-oxygen-py-oil diluent recycle stream to a py-oil mass flow rate of the biomass-derived pyrolysis oil stream.

11. The method of claim 1 wherein the first hydroprocessing conditions or the hydrocracking conditions or both include a reactor pressure of about 2 to about 20 MPa (g).

12. The method of claim 1 wherein the first hydroprocessing conditions include a fresh feed weight hourly space velocity of the biomass-derived pyrolysis oil stream per volume of from about 0.1 hr⁻¹to about 2 hr⁻¹.

13. The method of claim 1 wherein contacting the heated diluted py-oil feed stream comprises contacting the heated diluted py-oil feed stream with the first deoxygenating catalyst by a residence time of about 60 sec or less, wherein the residence time is defined by a time from when the biomass-derived pyrolysis oil stream is combined with the heated low-oxygen-py-oil diluent recycle stream to when the heated diluted py-oil feed stream initially contacts the first deoxygenating catalyst.

14. The method of claim 1 further comprising:

removing water from and separating the hydrocracked low-oxygen biomass-derived pyrolysis oil effluent to form a water-depleted low-oxygen py-oil recycle stream; and

heating at least a portion of the water-depleted low-oxygen py-oil recycle stream to form at last a portion of the heated low-oxygen py-oil diluent recycle stream.

15. The method of claim 1 further comprising:

removing water from and separating the hydrocracked low-oxygen biomass-derived pyrolysis oil effluent to form a water-depleted low-oxygen py-oil intermediate stream; and

contacting the water-depleted low-oxygen py-oil intermediate stream with a second deoxygenating catalyst in the presence of hydrogen at second hydroprocessing conditions effective to form an ultralow-oxygen biomass-derived pyrolysis oil effluent.

16. A method for deoxygenating a biomass-derived pyrolysis oil comprising:

contacting the heated diluted py-oil feed stream with a first deoxygenating catalyst in a first bed of a reactor in the presence of hydrogen at first hydroprocessing conditions effective to form a low-oxygen biomass-derived pyrolysis oil;

introducing a hydrogen stream to the reactor between the first bed and a second bed to adjust the ratio of hydrogen to hydrocarbon in the second bed and to adjust a temperature in the second bed;

17. The method of claim 16:

wherein contacting the heated diluted py-oil feed stream comprises contacting the heated diluted py-oil feed stream with the first deoxygenating catalyst at the first hydroprocessing conditions that include a reaction temperature of from about 150° C. to about 400° C.;

or

wherein contacting the low-oxygen biomass-derived pyrolysis oil comprises contacting the low-oxygen biomass-derived pyrolysis oil with the hydrocracking catalyst at the hydrocracking conditions that include a reaction temperature of from about 150° C. to about 500° C.;

or both.

18. The method of claim 16 wherein contacting the heated diluted py-oil feed stream comprises partially deoxygenating the heated diluted py-oil feed stream to form the low-oxygen biomass-derived pyrolysis oil that comprises a hydroprocessed organic phase that has a residual oxygen content of from about 5 to about 25 wt % of the hydroprocessed organic phase.

19. The method of claim 16 wherein combining comprises combining the biomass-derived pyrolysis oil stream with the heated low-oxygen-py-oil diluent recycle stream at a predetermined recycle ratio of from about 1:1 to about 10:1, wherein the predetermined recycle ratio is defined by a recycle mass flow rate of the heated low-oxygen-py-oil diluent recycle stream to a py-oil mass flow rate of the biomass-derived pyrolysis oil stream.

20. The method of claim 16 further comprising: