Patent Application
20150051427
The disclosure relates to a method of maximizing renewable fuel yield using renewed or recycled products in an integrated biomass conversion system.
Renewable energy sources are a substitute for fossil fuels and provide a means of reducing dependence on petroleum oil. Biomass is conventionally used as a feedstock to produce renewable energy sources, such as biofuels.
Fluidized catalytic thermolysis processes, such as cracking, have been developed that use biomass as a feedstock to produce useful biofuels. Such processes produce liquid products that might spontaneously separate into an aqueous phase and an organic phase. The organic phase is typically referred to as bio-oil. While thermolysis processes produce high yields of bio-oil, this pyrolysis oil produced is of low quality due to the high amount of oxygen present in the organic phase, which intrinsically retains water and precludes water/oil separation.
Bio-oil can be stabilized and converted to a conventional hydrocarbon fluid by removing oxygen. Hydrotreating, for instance involves contacting the bio-oil with hydrogen under higher pressures and temperatures than those conventionally used in the refining of fossil fuels. Hydrotreating makes the bio-oil more compatible with petroleum derived refinery streams.
It would be advantageous to enhance the efficiency of processing biomass into biofuels. For example, during these processes, organic liquids and gases, and spent inorganic solids are produced that constitute losses of bio-oil yield. It may be beneficial to use some or all of these spent materials, by-products and in-situ generated solids, liquids and gases during the conversion process to maximize the overall yield of renewable fuels.
It should be understood that the above-described discussion is provided for illustrative purposes only and is not intended to limit the scope or subject matter of the appended claims or those of any related patent application or patent. Thus, none of the appended claims or claims of any related application or patent should be limited by the above discussion or construed to address, include or exclude each or any of the above-cited features merely because of the mention thereof herein.
Accordingly, there exists a need for improved methods for producing renewable fuels from biomass having one or more of the attributes or capabilities described or shown in, or as may be apparent from, the other portions of this patent.
In various embodiments of the present disclosure, a process for producing a renewable fuel from biomass is provided. In this process, biomass may be converted in a biomass conversion unit in the presence of a biomass conversion catalyst. The converted biomass may then be separated into a fluid phase and a solid phase. The solid phase may contain a portion of the biomass conversion catalyst. A portion of the biomass conversion catalyst may also be entrained within the fluid phase.
The fluid phase may then be separated into an organic-enriched phase and an aqueous phase, which can also be called process water. The organic-enriched phase may then be fractionated into a full range bio-naphtha stream and a topped bio-oil stream, wherein the topped bio-oil stream comprises C6 or higher oxygenates. During said fractionation, the retained water might be separated as a water stream that can be mixed with the aqueous phase stream. Said aqueous phase stream comprises organic oxygenates of C5 or lower, “the lights”. Said lights may then be reconverted together with similar compounds present in the full range bio-naphtha stream from the fractionator. The reconverted lights contain of C6 or higher oxygenates that can be recovered from the aqueous stream. A slurry catalyst mix may be formed from a portion of the recovered-reconverted organic stream comprising oxygenates of C6 or higher (organic soluble) hydroprocessing active phase and the regenerated slurry dispersed catalyst. At least a portion of the biomass conversion catalyst and the catalyst mix may be fed into a slurry-phase hydroprocessor reactor. A solid-phase slurry dispersed catalyst may be formed in the slurry-phase hydroprocessor reactor. The solid-phase slurry dispersed catalyst may comprise atomically dispersoids of the active phase onto a support. The support may contain a portion of the biomass conversion catalyst which was entrained in the fluid phase.
The topped bio-oil stream mixed with at a least a portion of the recovered-reconverted over-C5 organic stream may then be fed into the slurry-phase hydroprocessor reactor and subjected to hydrogenation in the presence of the solid-phase slurry dispersed catalyst. Renewable fuels originating from hydrogenated topped bio-oil and recovered-reconverted over C5 organic streams may then be recovered by fractionation.
In some embodiments of the present disclosure, a process for enhancing the recovery of renewable fuels from biomass is disclosed wherein a fluid stream is first separated from a converted biomass feedstream. Said converted biomass feedstream being biomass subjected to treatment in the feed system and cracking in a fluidized catalytic cracking unit in the presence of a biomass conversion catalyst. The fluid stream of the conversion effluent from the biomass conversion unit is then separated into an organic-enriched phase, the renewable bio-oil and an aqueous phase. The renewable bio-oil phase is then separated into a full range bio-naphtha stream and a topped bio-oil stream comprising C6 or greater oxygenates. The topped bio-oil stream is then fed into a slurry-phase hydroprocessor reactor. A metal or a metal containing compound comprising the active phase of a solid-phase slurry dispersed catalyst is then fed to the slurry-phase hydroprocessor reactor and the active phase is then deposited onto a solid support. The topped bio-oil stream is combined with recovered-reconverted over-C5 organic and the bottoms of the hydroprocessor fractionator, and then subjected to hydrogenation. Renewable fuels are then obtained from the stream originating from the hydrogenated organic streams.
In many embodiments of the present disclosure, a process for producing renewable fuels from biomass is provided wherein biomass is first converted in a biomass conversion unit in the presence of a biomass conversion catalyst and the converted biomass is separated into a fluid phase and a solid phase. The fluid phase is then separated into an organic-enriched aqueous phase and non-condensable gas. A bio-oil stream and an aqueous stream are separated from the organic-enriched aqueous phase. Incompressible gases are separated from the non-condensable gas. Hydrogen is produced from the reformed incompressible gases. At least a portion of the gas-reformed hydrogen is then fed into the slurry-phase hydroprocessor reactor. The bio-oil stream is then fed into the slurry-phase hydroprocessor reactor and is then subjected to hydrogenation. Renewable fuels originating from hydrogenated bio-oil are obtained.
Accordingly, the present disclosure includes features and advantages which are believed to enable it to enhance the production of renewable fuels from biomass. Characteristics and advantages of the present disclosure described above and additional features and benefits will be readily apparent to those skilled in the art upon consideration of the following detailed description of various embodiments and referring to the accompanying drawings.
The following figures are part of the present specification, included to demonstrate certain aspects of various embodiments of this disclosure and referenced in the detailed description herein:
Characteristics and advantages of the present disclosure and additional features and benefits will be readily apparent to those skilled in the art upon consideration of the following detailed description of exemplary embodiments of the present disclosure and referring to the accompanying figures. It should be understood that the description herein and appended drawings, being of example embodiments, are not intended to limit the claims of this patent or any patent or patent application claiming priority hereto. On the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the claims. Many changes may be made to the particular embodiments and details disclosed herein without departing from such spirit and scope.
In showing and describing preferred embodiments in the appended FIGURE, common or similar elements are referenced with like or identical reference numerals or are apparent from the FIGURE and/or the description herein. The FIGURE is not necessarily to scale and certain features and certain views of the FIGURE may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness.
Certain terms are used herein and in the appended claims to refer to particular components. As one skilled in the art will appreciate, different persons may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. Also, the terms “including” and “comprising” are used herein and in the appended claims in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . . ” Further, reference herein and in the appended claims to components and aspects in a singular tense does not necessarily limit the present disclosure or appended claims to only one such component or aspect, but should be interpreted generally to mean one or more, as may be suitable and desirable in each particular instance.
Preferred embodiments of the present disclosure thus offer advantages over the prior art and are well adapted to carry out one or more of the objects of this disclosure. However, the present disclosure does not require each of the components and acts described above and are in no way limited to the above-described embodiments or methods of operation. Any one or more of the above components, features and processes may be employed in any suitable configuration without inclusion of other such components, features and processes. Moreover, the present disclosure includes additional features, capabilities, functions, methods, uses and applications that have not been specifically addressed herein but are, or will become, apparent from the description herein, the appended drawings and claims.
Referring to
In step 18, a biomass feedstock is fed from one or more external sources into a biomass conversion unit 24. The biomass feedstock may be in the form of solid particles of finely divided particles. The biomass may also be a liquid.
In an embodiment, the biomass particles can be fibrous biomass materials comprising cellulose. Examples of suitable cellulose-containing materials include algae, paper waste, and/or cotton linters. In one embodiment, the biomass particles can comprise a lignocellulosic material. Examples of suitable lignocellulosic materials include forestry waste such as wood chips, saw dust, pulping waste, and tree branches; agricultural waste such as corn stover, wheat straw, and bagasse; and/or energy crops such as eucalyptus, switch grass, and coppice.
The biomass feedstock may be provided to the biomass conversion unit via a biomass feed system (not shown). The feed system may be capable of feeding solid particulate biomass into the biomass conversion unit and performing any required pre-treatment (e.g. drying, roasting, torrefaction, demineralization, steam explosion, mechanical action, or a combination thereof) that facilitates subsequent conversion reactions. Said mechanical action may include kneading, milling, crushing, extruding, chopping, or a combination thereof.
In an embodiment, the biomass conversion unit 24 is a fluidized catalytic cracking reactor having a riser. It may be used with a solid/vapors disengaging system (e.g. solids separator 32) and a regenerator 42. A suitable biomass conversion catalyst (BCC) is provided to the exemplary biomass conversion unit 24, heated and mixed with the biomass feedstock. As is known, the BCC acts as a heat source enabling the cracking of the biomass feedstock into smaller molecules. An initial supply of BCC may be mixed with the biomass feedstock in the biomass feed system and/or introduced directly into the biomass conversion unit 24 (e.g. the riser). Subsequent supplies of BCC may be fresh catalyst from an external source and/or regenerated catalyst from the regenerator 42.
Any suitable BCC may be used in the biomass conversion unit 24. For example, the BCC may be (i) a solid acid, such as a zeolite, super acid, clay, etc., (ii) a solid base, such as metal oxides, metal hydroxides, metal carbonates, basic clays, etc., (iii) a metal or a compound containing a metal functionality, such as Fe, Cu, Ni, and may include transition metal sulfides, transition metal carbides, etc., or (iv) an amphoteric oxide, such as alumina, silica, titania, etc.
The biomass conversion unit 24 produces a conversion effluent. In the present embodiment, the thermocatalytic conversion of the biomass occurring in the biomass conversion unit 24 (e.g. the riser) may be characterized by short residence times and rapid heating of the biomass feedstock. The residence times may, for example, be under 20 seconds at temperatures between 250-1,000° C. Minerals may be contained in the solid biomass that, in some instances, possesses catalytic activity. During the chemical conversion occurring in the biomass conversion unit 24, some portions of these minerals may accumulate in the BCC inventory, while other portions may remain in the liquid effluent.
Referring still to the embodiment of
The fluid stream exiting the exemplary solids separator 32 is substantially solids-free and includes renewable bio-oil (RBO). This fluid stream is introduced into a fluids separator 52, which separates out non-condensable gas (NCG), process water, and an organic-enriched phase. Said organic enriched phase from herein after will be referred as the renewable bio-oil (RBO). One or more of these three outputs of the exemplary fluids separator 52 may contain organic compounds that are subsequently used in the system 10 to improve renewable fuel yields and increase product output. For example, in this particular embodiment, as will be described below, the RBO phase may be directed to a first fractionator 54, the process water provided to a recombinator 58 and the non-condensable gas fed to a pressure separator 70.
The illustrated first fractionator 54 separates the RBO into (i) full range bio-naphtha (“Bio-FRN”) fraction containing light oxygenates of C5 or less, (ii) a heavier bio-oil, or topped bio-oil fraction containing C6 or greater oxygenates and (iii) water. In a preferred embodiment, the topped bio-oil fraction is substantially free of light organic compounds. In this embodiment, the topped bio-oil fraction is provided (stream 56) to a dispersed-catalyst slurry-phase hydroprocessor reactor (“SHP reactor”) 90. As will be described further below, in the exemplary SHP reactor 90, solids retained by the topped bio-oil might contain catalytic components from the biomass conversion catalyst and mineral matter originally present in the biomass act as support for an active phase (externally supplied in stream 94) to form a solid-phase slurry dispersed catalyst (SHP catalyst). If desired, the water separated in the fractionator 54 may be combined as a water stream (step 66) with the process water from the fluid separator 52 for further use.
Still referring to the embodiment of
In the exemplary clarifier 62, water and organic liquid are physically separated using any suitable physical separation method/technique including, but not limited to sorption, fractionation, extraction, membrane, etc., as is and may become further known. For example, the clarifier 62 may have a two-stage system that includes a decanter and an adsorber (not shown). In the exemplary decanter, the organic phase will float on top of the aqueous phase, and the heaviest compounds will deposit towards the bottom. The aqueous phase is directed to the exemplary adsorber, which, in its adsorption mode, will render clear water that is substantially free of organic compounds. The clear water can be disposed of, or otherwise recycled into the system 10. For example, at least a portion of the clear water may be used for biomass pre-treatment (not shown) and returned to the biomass feed system (step 88). For another example, at least some of the clear water can be processed through a steamer, or evaporator, (not shown) and recycled to the fluids separator 52.
During regeneration in the exemplary adsorber, an organic fraction will desorb and may be mixed with the decanter's top and bottom fractions, constituting a liquid bio-oil fraction referred to as the recovered organic stream (“ROS”). In this embodiment, the recovered organic stream includes oxygenates having a molecular composition of C6 or greater. Thus, the heavier molecules with fuel value are separated from the water in the clarifier 62. As shown in step 64, if desired, at least a portion of the recovered organic stream from the clarifier 62 may be mixed with the topped bio-oil exiting (stream 56) from the first fractionator 54 to dilute the topped bio-oil before it enters the SHP reactor 90, facilitating its fluidity.
Still referring to the embodiment of
If liquefied bio-naphtha is output from the pressure separator 70 (or other liquefaction equipment), the liquefied bio-naphtha (LBN) may be directed to the recombinator 58 to react and convert into heavier compounds. During recombination in the illustrated recombinator 58, some organics originally present in the liquefied bio-naphtha and full range bio-naphtha fractions will react with the organics present in the process water 72. The exemplary recombinator 58 is operated under strong mixing conditions, such as those obtained under ultrasonic or mechanical stirring. Liquid-liquid extracting mixing will take place in the recombinator 58 during the recombination process. The usefulness of the liquefied bio-naphtha in the recombinator 58 may depend upon one or more variables, such as the nature of the biomass feedstock being used.
Some or all of the incompressible gases may be recycled (step 74) into the biomass conversion unit 24. In such instance, the incompressible gas may be used as lifting gas in the riser, improving hydrogen transfer in the biomass conversion unit and reducing the quantity of hydrogen otherwise removed from the biomass feedstock. If desired, some or all of the incompressible gas may be used (step 76) as a regenerant. For example, the incompressible gas may be used as regenerant in the exemplary adsorber of the clarifier 62, in the clarifying process during the regeneration cycle to recover the adsorbed organics. Some or all of the incompressible gas may be reformed to produce hydrogen, such as in a steam reformer 78 (step 80). The produced hydrogen may, for example, be thereafter supplied to the SHP reactor 90 (step 84), such as to supplement (and reduce) the supply of hydrogen to the SHP reactor 90 from an external source. If desired, it may be useful for the system 10 to be capable of having multiple possible uses for the incompressible gas. For example, if the reformer 78 is not operating, the incompressible gas may then be provided to the biomass conversion unit 24 as described above through line 88, and be used as lifting gas.
Still referring to the example of
Solids that can be used as the support phase or carrier may be fed into the SHP reactor 90 from any suitable source. For example, solid mineral matter having catalytic components in the topped bio-oil (stream 56) from the first fractionator 54 may be fed into the SHP reactor 90, as previously discussed. For another example, solids containing BCC in the withdrawn stream 92 from the first regenerator 42 may be fed into the SHP reactor 90.
The active phase may originate from an organometallic catalytic precursor and may be an oil-soluble active metal compound, such as an organometallic salt of a hydrogenating transition metal. The active phase may be fed into the SHP reactor 90 from any suitable source. In this embodiment, the active phase originates from one or more external sources (stream 94), and is dissolved in a small portion of the ROS from the clarifier 62 (stream 68) and, if desired, mixed with regenerated SHP catalyst containing solids (stream 110). Such streams may be combined in a mixer 96 to form a SHP catalyst mix. Said catalyst mix may include a sulfiding agent (from an external source, not shown), such as organic mercaptans, sulfides and/or disulfides, or combinations thereof. The amount of active phase may be calculated, for example, based on the total weight of the mixture of reacting streams entering the SHP reactor 90, including all or part of the (i) topped bio-oil stream 56, (ii) ROS 64 and (iii) ROS 68, such as the amount of active phase is in the range from about 100 to about 5,000 ppm, in the total feed-stream.
Hydrogen is also fed into the SHP reactor 90. The hydrogen may be provided from one or more suitable sources. For instance, hydrogen may be provided from an external source (step 98). As mentioned above, hydrogen from the reformer 78 may also be provided (step 84), either directly to the SHP reactor 90 or by being added to the externally supplied hydrogen.
In the present embodiment, the SHP catalyst mix (stream 106), hydrogen and ROS/topped-bio-oil feedstock mixture may be mixed in the SHP reactor 90 in which the SHP dispersed catalyst will be formed. In some embodiments, the SHP reactor 90 may be operated at a temperature between from about 300° C. to about 450° C., a pressure range between from about 1,500 psi to about 3,000 psi and a space velocity between from about 0.05 to about 10 h−1. In the exemplary SHP reactor 90, the SHP active phase provides hydrogenating functionality and BCC (e.g. from streams 56 and/or 92) provides cracking functionality, converting the bio-oils into drop-in fuel products, by removing oxygen via hydrodeoxygenation and hydrocracking. Solids in the illustrated SHP reactor 90 are used to recover the soluble active phase and will prevent the valuable metals contained in the SHP catalyst composition from ending up in the renewable fuels. A portion of spent SHP catalyst may be periodically removed from the SHP reactor 90, such as to control solids build-up and catalytic activity therein.
Still referring to
The spent solid phase from the SHP reactor 90 (and solids separator 100) typically includes (i) a carbonaceous material (char) that captured inorganic material originally present in the biomass feedstock, (ii) a carbonaceous material (coke) derived from the hydrotreating reactions and (iii) SHP catalyst that includes active phase and the BCC fines which could not be separated in the first solid separator 32.
In the present embodiment, this spent solid phase is provided (step 104) to a second regenerator 108, where it is regenerated to produce regenerated SHP catalyst and deactivated SHP catalyst. Under typical regeneration conditions having air heated to from about 300° C. to about 400° C., the regenerator 108 burns the coke and char deposited on the solids to create the regenerated SHP catalyst.
At least a portion of the regenerated SHP catalyst from the regenerator 108 may be recycled into the SHP reactor 90 to capture more of the solids. For example, regenerated SHP catalyst from the regenerator 108 may be fed (step 110) into the mixer 96 to be mixed with the active phase, producing the SHP catalyst mix provided to the SHP reactor 90. In such instances, the SHP catalyst mix includes a mixture of regenerated SHP catalyst from the regenerator 108, the active phase from an external source and a small amount of ROS from the clarifier 62.
The upgraded liquid product from the illustrated solids separator 100 is directed into a second fractionator 112 to produce renewable fuel blendstocks, including gasoline (RenGas), diesel (RenDiesel) and fuel oil (RenFO). Due to the cracking functionality in the SHP reactor 90, at least a portion of the RenFO fraction may be recycled (step 118) to the SHP reactor 90 to be converted into more RenGas and RenDiesel. The fractionator 112 may also produce gas output composed primarily of hydrocarbons. If desired, these gases can be fed to the reformer 78 (step 116) to derive hydrogen therefrom for further use in the system 10.
The methods that may be described above or claimed herein and any other methods which may fall within the scope of the appended claims can be performed in any desired suitable order and are not necessarily limited to any sequence described herein or as may be listed in the appended claims. Further, the methods of the present disclosure do not necessarily require use of the particular embodiments shown and described herein, but are equally applicable with any other suitable structure, form and configuration of components.
While exemplary embodiments of the disclosure have been shown and described, many variations, modifications and/or changes of the system, apparatus and methods of the present disclosure, such as in the components, details of construction and operation, arrangement of parts and/or methods of use, are possible, contemplated by the patent applicant(s), within the scope of the appended claims, and may be made and used by one of ordinary skill in the art without departing from the spirit or teachings of the disclosure and scope of appended claims. Thus, all matter herein set forth or shown in the accompanying drawings should be interpreted as illustrative, and the scope of the disclosure and the appended claims should not be limited to the embodiments described and shown herein.
