Butadiene production from used tires

Abstract

1. A process comprising: (a) providing a used tire feedstock; (b) gasifying the used tire feedstock to produce a gas stream comprising carbon monoxide, hydrogen, and carbon dioxide; (c) biosynthetically converting at least a portion of the carbon monoxide, hydrogen, and carbon dioxide in the gas stream to produce a first product stream; (d) converting at least a portion of the first product stream to a second product stream comprising acetaldehyde and hydrogen; (e) passing a portion of the hydrogen in the second product stream to the aforementioned step of biosynthetically converting at least a portion of the carbon monoxide, hydrogen, and carbon dioxide in the gas stream; and (f) converting at least a portion of the acetaldehyde to butadiene monomer.

Description

[Technical Field]

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 287,220, filed December 8, 2021, and U.S. Provisional Patent Application No. 63 / 329,255, filed April 8, 2022, which are incorporated herein by reference.

[0002] SUMMARY OF THE INVENTION An embodiment of the present invention relates to a process for converting used tires into butadiene monomer. Summary of the Invention [Problem to be solved by the invention]

[0003] Butadiene monomer is polymerized into polybutadiene and butadiene copolymers, such as poly(styrene-co-butadiene), poly(isoprene-co-butadiene), and poly(styrene-co-isoprene-co-butadiene). These polymers have many uses, but are used significantly in the manufacture of tires. Used tires, on the other hand, are not easily recycled but have been landfilled or incinerated for their fuel value. Methods have been proposed for pyrolyzing tires to syngas and then converting the syngas into useful materials. These methods lack industrial applicability, and therefore, improvements to this common route are desirable.

[0004] One or more embodiments of the present invention provide a process that includes: (a) providing a used tire feedstock; (b) gasifying the used tire feedstock to produce a gas stream comprising carbon monoxide, hydrogen, and carbon dioxide; (c) biosynthetically converting at least a portion of the carbon monoxide, hydrogen, and carbon dioxide in the gas stream to produce a first product stream; (d) converting at least a portion of the first product stream to a second product stream comprising acetaldehyde and hydrogen; (e) sending a portion of the hydrogen in the second product stream to the aforementioned step of biosynthetically converting at least a portion of the carbon monoxide, hydrogen, and carbon dioxide in the gas stream; and (f) converting at least a portion of the acetaldehyde to butadiene monomer.

[0005] Another embodiment of the present invention provides a process including: (a) providing a used tire feedstock; (b) optionally providing a co-feed comprising a carbonaceous material other than the used tire feedstock; (c) gasifying the used tire feedstock and any co-feed to produce a gas stream comprising carbon monoxide, hydrogen, and carbon dioxide; (d) introducing the gas stream into an aqueous medium, wherein the carbon monoxide, hydrogen, and carbon dioxide are converted to a first product stream; (e) converting the first product stream to a second product stream comprising acetaldehyde and hydrogen; (f) separating hydrogen from the second product stream, thereby forming a hydrogen stream; and (g) converting the acetaldehyde to a final product stream comprising butadiene.

[0006] Yet another embodiment of the present invention provides a vulcanizable composition comprising a polybutadiene or butadiene copolymer prepared by any of the above processes.

[0007] Yet another embodiment of the present invention provides a tire component prepared with the above vulcanizable composition.

[0008] Another embodiment of the present invention provides a tire manufactured by using the tire components described above. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a system for implementing an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Embodiments of the present invention are based, at least in part, on the discovery of a process that consumes used tires in the production of butadiene and, optionally, acetaldehyde. According to one or more embodiments, used tires are pyrolyzed to form a gas stream, which is then biosynthetically converted to ethanol. The ethanol is then converted to acetaldehyde, and this reaction produces a hydrogen by-product stream used in the upstream bioproduction of ethanol. The acetaldehyde can be purified and / or converted to butadiene monomer by reacting it with ethanol. It has been discovered that overall process efficiency and economics depend on the amount of hydrogen available during the biosynthesis of ethanol. Therefore, the present invention, which provides downstream production of hydrogen without the presence of carbon by-products, provides overall carbon efficiency. This is particularly advantageous in the present invention because used tires are the primary feedstock and contain a higher carbon-to-hydrogen molar ratio than other feedstocks, such as biomass. In one or more embodiments, butadiene is polymerized to form polybutadiene or butadiene copolymers, which are used in the preparation of vulcanizable compositions that are processed into tire components.

[0011] Process System and Overview An embodiment of the present invention can be described with reference to a diagram illustrating a system 20 for converting used tires to butadiene and optionally acetaldehyde. The system 20 includes a pyrolysis unit 31 followed in series by a bioreactor 51. The pyrolysis unit 31 is in direct or indirect fluid communication with the bioreactor 51 via a gas flow conduit 33. An acetaldehyde synthesis unit 71 (which may also be referred to as an acetaldehyde production unit 71) downstream of the bioreactor 51 is in direct or indirect fluid communication with the bioreactor 51 via an ethanol product conduit 53. The butadiene synthesis unit 91, also referred to as a butadiene production unit 91, is downstream of the acetaldehyde synthesis unit 71 and in direct or indirect fluid communication with the acetaldehyde synthesis unit 71 via an acetaldehyde product conduit 73. The acetaldehyde synthesis unit 71 is also in direct or indirect fluid communication with a hydrogen by-product conduit 75, which is in fluid communication with the bioreactor 51.

[0012] According to an embodiment of the present invention, pyrolysis unit 31 is adapted to receive tire feedstock, and optionally a co-feed, and thermally treat it to produce a gas stream comprising carbon monoxide (CO), hydrogen gas (H), and optionally carbon dioxide (CO). Bioreactor 51 contains one or more microbial cultures adapted to convert the carbon monoxide, hydrogen gas, and optionally the carbon dioxide into ethanol. The ethanol is transferred to acetaldehyde synthesis unit 71, where the ethanol is converted to acetaldehyde with hydrogen as a by-product. The acetaldehyde can be transferred to butadiene synthesis unit 91, where the acetaldehyde is converted to butadiene. By-product hydrogen from acetaldehyde synthesis unit 71 can be transferred to bioreactor 51 via conduit 75 or via conduit 99 in direct or indirect fluid communication with butadiene synthesis unit 91.

[0013] In one or more embodiments, the gas stream exiting the pyrolysis unit 31 is treated before being introduced into the bioreactor 51. For example, as shown, the gas product stream can be cooled in a heat exchanger 41. In one or more embodiments, the heat exchanger can receive cooling water from one or more downstream processes or units, such as a distillation column 61, which is described in more detail below. The gas stream can also be treated to remove one or more components before being introduced into the bioreactor 51. For example, as shown, the gas stream can be treated in a scrubber 45.

[0014] In either case, carbon monoxide, hydrogen, and optionally carbon dioxide are converted to ethanol within bioreactor 51. As shown, bioreactor 51 can include external inputs of hydrogen gas and water. In one or more embodiments, ethanol produced within bioreactor 51 is transferred from bioreactor 51 in a crude product stream via conduit 53 (e.g., the ethanol is dissolved in an aqueous medium). In one or more embodiments, the crude ethanol product stream can be filtered upon exiting bioreactor 51 or downstream thereof, for example, by using filtration unit 55. As one skilled in the art will appreciate, it is common to filter product streams exiting a bioreactor to prevent transfer of microorganisms to downstream processes. One skilled in the art will also appreciate that microorganisms filtered from the product stream, as well as carriers for the microorganisms, can be returned to the bioreactor. As shown, the microorganisms and / or carriers for the microorganisms can be returned to bioreactor 51 through microbial recirculation conduit 57. One skilled in the art will also appreciate that there can be a subsystem for introducing (i.e., inoculating) a desired microbial culture into bioreactor 51. These subsystems may include, for example, a unit (not shown) in fluid communication with the bioreactor 51 and adapted to cultivate microorganisms.

[0015] The crude ethanol product stream can be concentrated or otherwise purified before being introduced into acetaldehyde synthesis unit 71. For example, ethanol can be separated from the crude ethanol product stream in distillation unit 61, where the overhead (i.e., distillate) containing concentrated ethanol is sent to acetaldehyde synthesis unit 71 via conduit 65 and / or to butadiene production unit 91 via conduit 67, and the bottoms from the distillation can be recycled back to bioreactor 51, for example, via aqueous bottoms conduit 63.

[0016] Ethanol is converted to acetaldehyde in acetaldehyde production unit 71, which may be referred to as acetaldehyde synthesis unit 71 or acetaldehyde reactor 71. The acetaldehyde synthesis produces a crude product stream comprising acetaldehyde and a hydrogen by-product. In one or more embodiments, the crude acetaldehyde product stream can be transferred directly or indirectly to butadiene synthesis unit 91 via conduit 73. In other embodiments, the crude acetaldehyde is transferred directly or indirectly via conduit 79 to separation unit 81 (e.g., a distillation column, which may also be referred to as purification unit 81), where by-product hydrogen is separated from the acetaldehyde. The by-product hydrogen can be returned directly or indirectly to bioreactor 51 via conduit 75. The acetaldehyde stream from separation unit 81 can be sent to a market source via conduit 83 or to butadiene reactor 91 via conduit 85.

[0017] Acetaldehyde is converted to butadiene in synthesis unit 91 to produce a crude butadiene product stream, which can exit synthesis unit 91 directly or indirectly via conduit 93. In one or more embodiments, butadiene is separated from the crude butadiene stream in distillation column 95 to produce a purified butadiene stream that can be removed from the system via conduit 97. In embodiments in which a crude acetaldehyde stream containing hydrogen is fed to butadiene production unit 91, purification unit 95 (e.g., distillation unit 95) produces a by-product hydrogen stream that can be returned to bioreactor 51 via conduit 99.

[0018] Also shown in the figure, acetaldehyde synthesis unit 71 and / or butadiene production unit 91 can be supplemented with an external source of ethanol via conduit 77. This external source can be derived, for example, from the fermentation of an agricultural crop such as corn. In another embodiment, this external source can be derived from cellulosic ethanol produced from grasses, trees, algae, or other plants.

[0019] Although the systems and processes of the present invention are depicted as a single, integrated system in which each unit is in direct or indirect fluid communication with other units upstream and / or downstream thereof, those skilled in the art can readily envision less directly connected but still integrated systems and methods. For example, a system may exist in which the gasification unit 31 and bioreactor 51 are located in a first facility, and the acetaldehyde production unit 71 and butadiene production unit 91 are located in a second facility. The first facility (e.g., gasification unit 31 and bioreactor 51) may be indirectly connected to the second facility (e.g., acetaldehyde reactor 71 and butadiene reactor 91) via, for example, a pipeline that can transport ethanol from the first facility to the second facility. Alternatively, the ethanol may be transported from the first facility to the second facility via other forms of transportation, including trucks or railcars. Similarly, hydrogen produced in acetaldehyde reactor 71 can be returned to bioreactor 51 (i.e., from the second facility to the first facility) by pipeline, tanker, truck, or through exchange with a local hydrogen source. As used herein, unless otherwise specified, indirect fluid communication is understood to encompass these connections between various units.

[0020] Tire and carbonaceous material feedstock properties In one or more embodiments, the feedstock supplied to the pyrolysis unit 31 includes tire feedstock from used tires, which may also be referred to as used tire feedstock. As one skilled in the art will understand, tire feedstock may include vulcanized polymers, carbon black fillers, silica, resins, oils, fiber yarns, and metals. The vulcanized polymers may include sulfur-bridged residues of natural rubber and / or one or more synthetic elastomers, including diene polymers and copolymers. In one or more embodiments, used tire feedstock may include shredded or otherwise comminuted tires from which one or more components of the used tires have been removed. For example, tire feedstock may be processed to remove metals by methods known in the art (e.g., magnetic separation). Alternatively, or in combination, used tire feedstock may be optionally processed to remove fiber reinforcement, such as fiber yarns or cords, which one skilled in the art will understand are often found in conjunction with vulcanized rubber in many tire components. Alternatively, or in combination, the used tire feedstock may be optionally processed to remove inorganic materials, such as silica fillers, which those skilled in the art will appreciate are often found in used tire components. In any event, the tire feedstock may be processed into tire shreds, tire chips, or ground or crumb rubber and fed to the pyrolysis unit.

[0021] In one or more embodiments, the tire feedstock is characterized by relatively low amounts of metals, which may result from pre-treatment of the tire feedstock to remove metals. In one or more embodiments, the tire feedstock contains less than 25 wt. %, in other embodiments less than 15 wt. %, and in other embodiments less than 1 wt. % metals, based on the total weight of the feedstock provided to pyrolysis in accordance with the present invention.

[0022] In one or more embodiments, the tire feedstock is characterized by a relatively small amount of fiber yarns or cords, which may result from pre-processing of the tire feedstock to remove the fiber yarns or cords. In one or more embodiments, the tire feedstock comprises less than 5% by weight, in other embodiments less than 4% by weight, in other embodiments less than 3% by weight, in other embodiments less than 2% by weight, and in other embodiments less than 3% by weight of fiber yarns or cords, based on the total weight of the feedstock provided to pyrolysis according to the present invention.

[0023] In one or more embodiments, the tire feedstock is characterized by a relatively small amount of inorganic fillers (e.g., silica), which may result from pre-processing of the tire feedstock to remove the inorganic fillers. In one or more embodiments, the tire feedstock comprises less than 30 wt. %, in other embodiments less than 20 wt. %, in other embodiments less than 10 wt. %, and in other embodiments less than 5 wt. % inorganic fillers, based on the total weight of the feedstock provided to pyrolysis in accordance with the present invention.

[0024] In one or more embodiments, the used tire feedstock comprises tire residue from passenger tires, hi other embodiments, the used tire feedstock comprises tire residue from non-passenger tires, such as, but not limited to, truck and bus tires, off-the-road vehicle tires, agricultural tires, and race tires.

[0025] In one or more embodiments, the used tire has a tensile strength of 640 kg / m 3 In other embodiments, more than 720 kg / m 3 In other embodiments, 770 kg / m 3 The granular material may be characterized by a compressed density of greater than 0.05 g, where density is determined by ASTM D 698-07.

[0026] As noted above, the feedstock to the pyrolysis unit includes tire feedstock and, optionally, a complementary feedstock. In one or more embodiments, the complementary feedstock, which may also be referred to as a co-feed, includes a carbonaceous material other than the tire feedstock. Carbonaceous material refers to any carbonaceous material, whether in a solid, liquid, gas, or plasma state. Non-limiting examples of carbonaceous materials include carbonaceous liquid products, industrial liquid recycle, municipal solid waste (MSW or msw), urban waste, agricultural materials, forestry materials, wood waste, building materials, plant materials, industrial waste, fermentation waste, petrochemical by-products, alcohol production by-products, coal, plastics, waste plastics, coke oven tar, lignin, black liquor, polymers, waste polymers, polyethylene terephthalate (PETA), polystyrene (PS), sewage sludge, animal waste, crop residues, energy crops, forestry processing residues, wood processing residues, livestock waste, poultry waste, food processing residues, ethanol by-products, spent grain, spent microorganisms, municipal waste, construction waste, demolition waste, biomedical waste, hazardous waste, or combinations thereof. In one or more embodiments, the carbonaceous material comprises biomass. In one or more embodiments, the biomass is residue, including, but not limited to, residues of sugarcane, sorghum, and guayule plants.

[0027] In a further embodiment, the guayule residue is produced as a result of a process for extracting rubber and resin from guayule plants, as described in U.S. Patent Application Publication No. 2022 / 0356273 A1, which is incorporated herein by reference. A method for desolventizing guayule residue is described in U.S. Patent No. 10,132,563, which is also incorporated herein by reference. In one or more embodiments, the guayule residue contains 1 wt. % or less of organic solvent (based on the total weight of the dry residue). In certain embodiments, the dry residue contains 0.5 wt. % or less of organic solvent (based on the total weight of the dry residue). In one or more embodiments, the dry residue may contain a certain amount of water and higher-boiling terpenes. In certain embodiments, the total amount of water and high-boiling terpenes in the dry residue may be higher than the content of organic solvents. In certain embodiments, a resin content (including high-boiling terpenes) in the dry residue is generally acceptable, and in some instances, is actually preferred.

[0028] In one or more embodiments, the co-feed (e.g., biomass or municipal waste) is 600 kg / m 3 in other embodiments, 580 kg / m 3 and less than 560 kg / m in other embodiments. 3 It may be characterized by a compressed density of less than 0.05, the density being determined by ASTM D 698-07.

[0029] The feedstock may be characterized by the amount of co-feed (e.g., biomass or municipal waste). In one or more embodiments, the feedstock comprises from about 0 to about 95 wt. %, in other embodiments from about 1 to about 75 wt. %, and in other embodiments from about 2 to about 55 wt. % of the co-feed, with the remainder comprising used tires. In one or more embodiments, the feedstock comprises less than 95 wt. %, in other embodiments less than 80 wt. %, and in other embodiments less than 70 wt. % of the co-feed. In these or other embodiments, the feedstock comprises more than 10 wt. %, in other embodiments more than 20 wt. %, in other embodiments more than 30 wt. %, in other embodiments more than 40 wt. %, in other embodiments more than 50 wt. %, and in other embodiments more than 70 wt. % used tires, with the remainder comprising complementary feedstocks.

[0030] Pyrolysis of tires and optionally biomass According to embodiments of the present invention, the feedstock (including tire feedstock and optional co-feed) is pyrolyzed into a gas stream containing hydrogen, carbon monoxide, and optionally carbon dioxide by using techniques commonly known in the art. As those skilled in the art will appreciate, these processes can include gasification processes, and it is also known that these processes can be tailored to control the chemistry of the resulting gas stream. For example, the degree of combustion can be controlled by controlling the amount of oxygen present during pyrolysis. In one or more embodiments, the pyrolysis step is carried out in a substantially inert environment.

[0031] Processes that may be used for the pyrolysis step may include pyrolysis reactions such as those disclosed in U.S. Patent Application Publication Nos. 20210207037, 20190295734, 20190249089, 20180273415, 20170009162, 20170002271, 20160107913, 20160068773, 20160024404, 20140182205, 20140157667, and 20140100294, which are incorporated herein by reference.

[0032] In one or more embodiments in which the feedstock includes both tire feedstock and a co-feed, the tire feedstock and the co-feed can be introduced simultaneously into the same pyrolysis unit. For example, the tire feedstock and the co-feed can be premixed in a desired ratio to form the feedstock supplied to the pyrolysis unit. Alternatively, separate streams of the tire feedstock and the co-feed can be fed separately and individually to the pyrolysis unit at desired rates. In yet other embodiments, the two feedstocks (i.e., the tire feedstock and the co-feed) can be processed sequentially in the same pyrolysis unit. In yet other embodiments, the two feedstocks (i.e., the tire feedstock and the co-feed) can be processed in separate pyrolysis units operating in parallel, and the gas streams produced by each unit can then be combined to achieve a desired ratio of gas components.

[0033] Gas product stream characteristics As described above, the gas product stream produced by pyrolysis unit 31 comprises carbon monoxide, hydrogen, and optionally carbon dioxide. In one or more embodiments, the gas product stream comprises from about 5 to about 50 weight percent, in other embodiments from about 7 to about 25 weight percent, and in other embodiments from about 8 to about 15 weight percent carbon dioxide. In one or more embodiments, the gas product stream comprises from about 10 to about 85 weight percent, in other embodiments from about 20 to about 65 weight percent, and in other embodiments from about 25 to about 45 weight percent hydrogen. In one or more embodiments, the gas product stream comprises from about 20 to about 85 weight percent, in other embodiments from about 30 to about 75 weight percent, and in other embodiments from about 40 to about 60 weight percent carbon monoxide. In one or more embodiments, the gas product stream produced by pyrolysis comprises from about 40 to about 80 weight percent, in other embodiments from about 45 to about 75 weight percent, and in other embodiments from about 50 to about 70 weight percent carbon (i.e., carbon in carbon-based compounds), based on the total weight of the gas product stream.

[0034] Gas flow adjustment In one or more embodiments, the gas stream is conditioned (i.e., treated) before providing it to bioreactor 21. In one or more embodiments, the gas product stream from pyrolysis carried by conduit 33 may be pressurized. In one or more embodiments, pressurization of the gas stream achieves a pressure sufficient to overcome opposing forces within the bioreactor. As one skilled in the art will appreciate, this allows for gas flow through the bioreactor and allows inert gases (e.g., nitrogen) within the gas stream to enter the headspace of the reactor. In one or more embodiments, the gas stream is pressurized to a pressure of about 5 to about 20 bar.

[0035] Alternatively, the gas stream can be cooled in a heat exchanger 41. As will be appreciated by those skilled in the art, the heat exchanger 41 may include a water cooling unit. In one or more embodiments, the gas stream is cooled to a temperature below that which would otherwise have a detrimental effect on the microbial culture in the bioreactor. In one or more embodiments, the gas stream is cooled to a temperature of about 25 to about 45° C. prior to delivery to the bioreactor.

[0036] Additionally, the gas stream may be treated in a scrubber 45 before being introduced into the bioreactor. In one or more embodiments, this may include the use of a catalyst to remove hydrogen sulfide (e.g., iron oxide). The gas stream may also be treated to remove halides (e.g., treatment with calcium carbonate or sodium carbonate).

[0037] Bioreactor As described above, bioreactor 51 includes one or more microorganisms that consume one or more components of the gas product stream to produce ethanol. In one or more embodiments, bioreactor 51 may include a single reaction vessel or may include multiple (i.e., two or more) reaction vessels that may operate in a complementary manner. For example, two or more reaction vessels may operate in parallel or series to promote the desired reaction (i.e., bioconversion of the gas product stream to ethanol). Those skilled in the art will generally understand the appropriate conditions to be maintained in a bioreactor to sustain the microorganisms and promote the desired reaction. In one or more embodiments, water is a reactant and serves as the reaction medium in the bioreactor.

[0038] In one or more embodiments, the reactor medium in the bioreactor is maintained at a temperature of about 30 to about 45° C. In these or other embodiments, the reactor medium in the bioreactor is maintained at a pH of about 4 to about 7.

[0039] In one or more embodiments, the bioreactor includes at least one inlet for introducing a gas stream into the bioreactor and at least one outlet for removing a product stream from the bioreactor. In one or more embodiments, the bioreactor includes an outlet for a gas by-product stream. In one or more embodiments, the bioreactor is a closed system except for the inlet and outlet. In other embodiments, the bioreactor is an open system. In one or more embodiments, the bioreactor is selected from a continuous stirred tank reactor, a gas lift reactor, a loop reactor, and a fluidized bed reactor. In one or more embodiments, the bioreactor has a volume greater than 500 L, in other embodiments greater than 1000 L, and in other embodiments greater than 1500 L.

[0040] microorganisms Microorganisms or genetically modified microorganisms capable of or adapted to synthesize ethanol from gas product streams are generally known in the art. For example, Zymomonas mobilis or Lactococcus strains, as well as certain Clostridium strains, are known to produce ethanol from carbon-containing gaseous substrates. The art includes U.S. Patent Application Publication Nos. 20210284592, 20200255362, 20200156973, 20180264375, 20170226538, 20170225098, 20170183690, 20160160223, 20160017276, 20160010116, 20150376654, 2015 Other useful examples abound, such as those shown in US Pat. Nos. 0353965, 20150337341, 20150299737, 20150152441, 20150087037, 20140377826, 20130316424, 20130252230, 20130230894, and 20130224839, which are incorporated herein by reference.

[0041] Ethanol-containing product stream from the bioreactor As described above, ethanol exits the bioreactor 51 in an aqueous product stream, which may be referred to as an ethanol product stream. This aqueous product stream can be filtered as it exits the bioreactor. During operation, filtering the product stream as it exits the bioreactor can prevent the transfer of any media used to immobilize the microorganisms, thereby helping to prevent the transfer of the microorganisms from the bioreactor to downstream processes. In addition to, or instead of, filtering the ethanol-containing product stream as it exits the bioreactor, the product stream can be filtered and / or sterilized in one or more intermediate units located downstream of the bioreactor. In addition to, or instead of, a filtration unit, the product stream may undergo separation, for example, in a centrifugation unit. Or, in other embodiments, in addition to, or instead of, filtration or centrifugation, a clarification unit (e.g., a settling tank) can be used to further process the product stream. Instead of, or in addition to, filtration, centrifugation, and / or clarification, the product stream may be sterilized. For example, the sterilization unit may utilize UV ​​sterilization, heat, or gamma radiation to treat the product stream.

[0042] Ethanol concentration / separation As discussed above, following any processing in unit 55, the ethanol-containing product stream can be processed to separate the ethanol from other components of the aqueous stream. This can include distilling the ethanol-containing stream in separation unit 61. According to these embodiments, the ethanol can be collected as an overhead stream that can be characterized by an ethanol concentration of greater than 80 wt%, in other embodiments greater than 90 wt%, and in other embodiments greater than 93 wt%. In these or other embodiments, the overhead stream (i.e., the ethanol-containing stream) can contain less than 10 wt%, in other embodiments less than 8 wt%, and in other embodiments less than 1 wt% water.

[0043] In one or more embodiments, the overhead ethanol stream can optionally be further processed to purify the ethanol stream before introducing the ethanol into acetaldehyde production unit 71. For example, the ethanol stream can be dehydrated or dried by treating the ethanol stream with one or more water adsorption beds containing a drying material, such as molecular sieves.

[0044] Acetaldehyde production As indicated above, ethanol is converted to acetaldehyde in production unit 71. In one or more embodiments, substantially all of the ethanol produced in bioreactor 51 (i.e., substantially all of the ethanol in the ethanol-containing product stream) is introduced into acetaldehyde production unit 71. In these or other embodiments, ethanol obtained from outside the process of the present invention (e.g., ethanol from crop fermentation) is also introduced into acetaldehyde production unit 71 to supplement the production of acetaldehyde. In one or more embodiments, the weight ratio of ethanol supplied to acetaldehyde production unit 71 from bioreactor 51 to ethanol supplied to acetaldehyde production unit 71 from other sources (e.g., ethanol from crop fermentation) is from about 1:0 to about 1:10, from about 1:0.3 to about 1:7 in other embodiments, and from about 1:1 to about 1:5 in other embodiments.

[0045] As those skilled in the art will appreciate, the synthesis of acetaldehyde involves the partial dehydrogenation of ethanol to obtain a hydrogen by-product stream. As noted above, hydrogen can be sent to bioreactor 51, which can advantageously offset the hydrogen deficiency of the process. Those skilled in the art will appreciate that if additional ethanol is converted to acetaldehyde, the introduction of ethanol from a source outside the bioreactor process (i.e., outside bioreactor 51) can further alleviate the hydrogen deficiency within bioreactor 51, which allows for greater production of hydrogen.

[0046] In one or more embodiments, in acetaldehyde production unit 71, ethanol undergoes dehydrogenation at elevated temperatures over a suitable catalyst, such as a copper-based catalyst. For example, the reaction can be carried out in a fixed-bed reactor. In one or more embodiments, the dehydrogenation of ethanol in unit 71 is carried out at temperatures of about 200 to about 350°C, or in other embodiments, about 250 to about 300°C.

[0047] Butadiene production In one or more embodiments, the acetaldehyde produced in unit 71 is converted to butadiene monomer in butadiene production unit 91. In one or more embodiments, butadiene production involves reacting ethanol with acetaldehyde to produce 1,3-butadiene by utilizing reaction techniques commonly known in the art, such as those described by Zhang, "Mechanistic Insight into the Meerwein-Ponndorf-Verley Reaction and Relative Side Reactions over MgO in the Process of Ethanol to 1,3-butadiene: a DFT Study," Ind. Eng. Chem. Res., 2021, 60, 2871-2880. As one skilled in the art will appreciate, this reaction can be carried out at elevated temperatures over a suitable catalyst, such as a tantalum-promoted porous silica catalyst. Other catalysts for converting acetaldehyde and ethanol to butadiene are also known in the art and can be used. In one or more embodiments, the reaction is carried out in a fixed bed reactor operating at a temperature of from about 300 to about 450°C, or from about 350 to about 400°C in other embodiments.

[0048] In one or more embodiments, the reactant feed to butadiene production unit 91 comprises an ethanol to acetaldehyde molar ratio (i.e., moles of ethanol to moles of acetaldehyde) of at least 1:1, in other embodiments at least 2:1, in other embodiments at least 2.5:1, in other embodiments at least 4:1, and in other embodiments in the range of from about 1:1 to about 5:1.

[0049] The feed to butadiene production unit 91 is characterized by low levels of impurities (i.e., components other than acetaldehyde and ethanol). In one or more embodiments, the feed stream to butadiene production unit 91 contains less than 10 wt. % impurities, in other embodiments less than 5 wt. %, and in other embodiments less than 2 wt. % impurities, based on the total weight of the input stream.

[0050] The crude butadiene stream exiting butadiene reactor 91 via conduit 93 generally includes 1,3-butadiene monomer, unreacted ethanol, unreacted acetaldehyde, water as a by-product of the reaction, and other by-products. In one or more embodiments, the yield of 1,3-butadiene based on acetaldehyde is greater than 20 mole %, greater than 30 mole % in other embodiments, and greater than 40 mole % in other embodiments. In these or other embodiments, the yield of 1,3-butadiene based on acetaldehyde is less than 70 mole %, less than 60 mole % in other embodiments, and less than 55 mole % in other embodiments.

[0051] In one or more embodiments, the crude butadiene product stream undergoes a first separation, which may include distillation. In one or more embodiments, butadiene is separated as an overhead stream and the remaining components of the product stream are separated as a bottoms stream. The bottoms stream may then be further separated to separate ethanol and acetaldehyde from water and other components of the stream. The ethanol and acetaldehyde, which may be separated as an overhead stream, may then be recycled back to butadiene production unit 91 for conversion to butadiene. [Industrial Applicability]

[0052] In one or more embodiments, the 1,3-butadiene produced by the methods of the present invention can be used in the production of polybutadiene or butadiene copolymers (which may also be referred to as polybutadiene copolymers), which can be used in the manufacture of tire components. For purposes of this specification, these polymers may be referred to as cyclic synthetic rubbers or cyclic synthetic polybutadiene-butadiene copolymers. As a result, the practice of the present invention provides a method in which waste materials from used tires are converted back into useful tires. In other words, a tire recycling method is provided.

[0053] The synthesis of polybutadiene or polybutadiene copolymers from butadiene monomers is well known and can be achieved by using several synthetic routes (i.e., polymerization mechanisms and techniques). For example, the monomers can be polymerized by free radical emulsion polymerization, anionic polymerization, or coordination catalysis using, for example, nickel- or neodymium-based catalyst systems.

[0054] As those skilled in the art will appreciate, comonomers that can be copolymerized with butadiene to form polybutadiene copolymers include, but are not limited to, vinyl aromatic monomers such as styrene and other diene monomers such as isoprene. Such other monomers can be derived from sustainable processes. Polymers synthesized from butadiene produced according to embodiments of the present invention may be referred to as vulcanizable or elastomeric polymers and generally include polydienes and polydiene copolymers. Specific polymers that can be produced and used in tire manufacturing include, but are not limited to, polybutadiene, poly(styrene-co-butadiene), poly(styrene-co-isoprene-co-butadiene), poly(isoprene-co-butadiene), and their functionalized derivatives.

[0055] The polybutadiene and polybutadiene copolymers produced by the present invention exhibit excellent viscoelastic properties and are particularly useful in the manufacture of various tire components, including, but not limited to, tire treads, sidewalls, subtreads, and bead fillers. These polymers can be used as all or part of the elastomeric component of tire stock. When the polymers produced by the present invention are used with other vulcanizable polymers to form the elastomeric component of tire stock, these other vulcanizable polymers can be natural rubber, synthetic rubber, and mixtures thereof. Examples of synthetic rubbers include polyisoprene, poly(styrene-co-butadiene), and other polybutadienes with low and / or cis-1,4 bond content, poly(styrene-co-butadiene-co-isoprene), and mixtures thereof. The polymers of the present invention can also be used in the manufacture of hoses, belts, shoe soles, window seals, other seals, vibration-damping rubber, and other industrial products.

[0056] Not only do practices of the present invention provide a method for recycling tires by using post-consumer tires as a feedstock for producing polymers that can be compounded back into tires, but they also advantageously provide a method for producing tires with a relatively high content of sustainable ingredients, including recycled or naturally derived materials. Furthermore, these tires or tire components, while characterized by a high sustainable content, contain a threshold amount of cyclic synthetic rubber. For example, tires or tire components of the present invention can contain greater than 40% by weight, in other embodiments greater than 50% by weight, and in other embodiments greater than 60% by weight of sustainable materials. In one or more embodiments, the tire or tire component contains from about 40 to about 90% by weight, in other embodiments from about 45 to about 85% by weight, and in other embodiments, from about 50 to about 80% by weight of styrene. In combination, the rubber component of the tires or tire components of the present invention contains greater than 10% by weight, in other embodiments greater than 20% by weight, in other embodiments greater than 30% by weight, in other embodiments greater than 40% by weight, in other embodiments greater than 45% by weight, and in other embodiments greater than 50% by weight of cyclic synthetic rubber, including synthetic rubber produced according to embodiments of the present invention.

[0057] As described above, the vulcanizable composition of the present invention includes a rubber component. This rubber component includes cyclic synthetic rubber produced according to an embodiment of the present invention. The rubber component may also include other synthetic rubbers, such as synthetic rubber derived from petroleum-based sources and not recycled, synthetic rubber derived from other sustainable processes, and natural rubber. As those skilled in the art will appreciate, natural rubber is synthesized by and obtained from plants. For example, natural rubber can be obtained from Hevea rubber trees, guayule shrub, gopher plants, mariola, rabbitbrush, milkweed, goldenrods, pale Indian plantain, rubber vine, Russian dandelions, mountain mint, American germander, and tall bellflower.

[0058] If used, other synthetic polymers include, but are not limited to, synthetic polyisoprene, polybutadiene, polyisobutylene-co-isoprene, neoprene, poly(ethylene-co-propylene), poly(styrene-co-butadiene), poly(styrene-co-isoprene), poly(styrene-co-isoprene-co-butadiene), poly(isoprene-co-butadiene), poly(ethylene-co-propylene-co-diene), polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, and mixtures thereof. These elastomers can have a myriad of macromolecular structures, such as linear, branched, and star structures.

[0059] Generally, the rubber compositions of the present invention comprise from about 30 to about 65 weight percent, and in other embodiments from about 35 to about 60 weight percent, and in other embodiments from about 40 to about 55 weight percent elastomer, based on the total weight of the tire components.

[0060] As alluded to above, the rubber composition includes fillers, such as organic and inorganic fillers. Examples of organic fillers include carbon black and starch. Examples of inorganic fillers include silica, aluminum hydroxide, magnesium hydroxide, mica, talc (hydrated magnesium silicate), and clay (hydrated aluminum silicate). In some embodiments, mixtures of different fillers may be advantageously used.

[0061] The total filler amount used in the rubber composition may be up to about 150 parts by weight per 100 parts by weight of rubber (phr), with from about 30 to about 125 phr, or from about 40 to about 110 phr being typical. In certain embodiments, the total filler content is greater than about 100 phr. In other embodiments, the total filler content is from about 50 to about 100 phr, and in further embodiments, from about 55 to about 95 phr.

[0062] Conventional carbon blacks generally known in the art can be used. In one or more embodiments, carbon blacks include furnace black, channel black, and lamp black. More specific examples of carbon blacks include ultra-abrasive furnace black, medium ultra-abrasive furnace black, high-abrasive furnace black, high-speed extrusion furnace black, fine furnace black, semi-reinforced furnace black, medium-processed channel black, hard-processed channel black, conductive channel black, and acetylene black.

[0063] In certain embodiments, the carbon black has a surface area (EMSA) of at least 20 m 2 / g, in other embodiments at least 35m 2The surface area may be expressed in terms of % by mass per gram, and the surface area value may be determined using the cetyltrimethylammonium bromide (CTAB) technique according to ASTM standard D-1765. The carbon black may be in pelletized or non-pelletized flocculent form. The preferred form of the carbon black may depend on the type of mixing equipment used to mix the rubber compound.

[0064] In one or more embodiments, recycled carbon black may be utilized. Such recycled materials include reclaimed or recycled vulcanized rubber, which is typically reclaimed from manufactured articles such as pneumatic tires, industrial conveyor belts, power transmission belts, and rubber hoses. Recycled carbon black may be obtained by a pyrolysis process or other known methods for obtaining recycled carbon black. In one aspect, recycled carbon black may be formed from the incomplete combustion of recycled rubber feedstock or rubber articles. In another aspect, recycled carbon black may be formed from the incomplete combustion of oil-containing feedstocks resulting from tire pyrolysis processes. The carbon black used in preparing the vulcanizable elastomeric composition may be in pelletized or non-pelletized floc form.

[0065] The amount of total filler used in the rubber composition may be up to about 75 parts by weight per 100 parts by weight of rubber (phr), with from about 5 to about 60 phr, or from about 10 to about 55 phr being typical.

[0066] The rubber composition may further include a filler in the form of one or more types of reclaimed rubber in particulate form. Reclaimed particulate rubber is typically broken down and reclaimed (or recycled) by any of several processes, including physical breakdown, grinding, chemical breakdown, devulcanization, cryogenic grinding, and combinations thereof. The term reclaimed particulate rubber can refer to both vulcanized and devulcanized rubber, with devulcanized recycled rubber or recycled rubber (reclaimed rubber) referring to rubber that has been vulcanized, ground into particles, and may have undergone substantial or partial devulcanization. In one example, the reclaimed particulate rubber used in the rubber composition is essentially free of reclaimed rubber resulting from devulcanization. In situations where the vulcanized rubber contains wire or textile fiber reinforcement, such wire or fiber reinforcement may be removed by any suitable process, such as magnetic separation, air aspiration, and / or air flotation. In certain embodiments, "recycled particulate rubber" includes cured, i.e., vulcanized (crosslinked), rubber that has been ground or powdered into particulate matter having an average particle size as discussed below.

[0067] Certain silicas can be considered sustainable materials. Some commercially available silicas that can be used as sustainable materials in the present invention include Hi-Sil™ 215, Hi-Sil™ 233, and Hi-Sil™ 190 (PPG Industries, Inc.; Pittsburgh, Pa.). Other suppliers of commercially available silica include Grace Davison (Baltimore, Md.), Degussa Corp. (Parsippany, NJ), Rhodia Silica Systems (Cranbury, NJ), and JM Huber Corp. (Edison, NJ). Other sustainable silicas include those derived from rice husk ash.

[0068] In one or more embodiments, silica can be characterized by its surface area, which is a measure of its reinforcing properties. The Brunauer, Emmet and Teller (Brunauer, Emmet and Teller, "BET") method (described in J. Am. Chem. Soc., 1939, vol. 60, 2 pp. 309-319) is an accepted method for determining surface area. The BET surface area of ​​silica is generally 450 m 2 / g. A useful range of surface area is from about 32 to about 400 m 2 / g, about 100~250m 2 / g, and about 130 to about 240 m 2 / g, and about 170 to about 220 m 2 In certain embodiments, the silica has a viscosity of 190 to about 280 m / g. 2 / g BET surface area. The pH of the silica is generally from about 5 to about 7, or slightly above 7, or in other embodiments, from about 5.5 to about 6.8.

[0069] In one or more embodiments, when silica is used as a filler (alone or in combination with other fillers), a coupling agent and / or shielding agent may be added to the rubber composition during mixing to enhance interaction of the silica with the elastomer. Useful coupling agents and shielding agents are disclosed in U.S. Patent Nos. 3,842,111, 3,873,489, 3,978,103, 3,997,581, 4,002,594, 5,580,919, 5,583,245, 5,663,396, 5,674,932, and 5,680,919. Nos. 4,171, 5,684,172, 5,696,197, 6,608,145, 6,667,362, 6,579,949, 6,590,017, 6,525,118, 6,342,552, and 6,683,135, which are incorporated herein by reference.

[0070] The amount of silica used in the rubber composition can be from about 1 to about 150 phr, or in other embodiments, from about 5 to about 130 phr. The useful upper range is limited by the high viscosity imparted by the silica. In certain embodiments, the silica used in the rubber composition is derived solely from rice husk ash, and in other embodiments, the rubber composition contains no silica from a non-rice husk ash-derived process. When silica is used with carbon black, the amount of silica or carbon black, respectively, can be as low as about 1 phr. Generally, the amount of binder and shielding agent ranges from about 4% to about 20% by weight, based on the weight of the silica used. In one or more embodiments in which carbon black and silica are used in combination as fillers, the weight ratio of silica to total filler can be from about 5% to about 99% by weight of the total filler, in other embodiments, from about 10% to about 90% by weight of the total filler, or in yet other embodiments, from about 50% to about 85% by weight of the total filler. In certain embodiments, the silica and carbon black fillers used in the rubber composition are selected from the group consisting of sustainable pyrolytic carbon black and / or rice husk ash derived silica.

[0071] A number of rubber curing agents (also called vulcanizing agents) may be used, including sulfur or peroxide-based cure systems. Curing agents are described in Kirk-Othmer, Encyclopedia of Chemical Technology, Vol. 20, pp. 365-468, (3 rd Ed.1982), especially Vulcanization Agents and Auxiliary Materials, pgs.390-402, and AYCoran, Vulcanization, Encyclopedia of Polymer Science and Engineering, (2 nd Ed. 1989), which are incorporated herein by reference. The vulcanizing agents may be used alone or in combination.

[0072] Other components typically used in rubber compounding may also be added to the rubber composition, including accelerators, accelerator activators, oils, plasticizers, waxes, antiscorch agents, processing aids, zinc oxide, tackifying resins, reinforcing resins, fatty acids such as stearic acid, deflocculants, antidegradants such as antioxidants and antiozonants.

[0073] Regarding oils, sustainable oils, including plant-based oils and bio-based oils, may be used. Plant-based oils may include plant-based triglycerides. Exemplary oils include, but are not limited to, palm oil, soybean oil (also referred to herein as soybean oil), rapeseed oil, sunflower seed oil, peanut oil, cottonseed oil, palm kernel oil, coconut oil, olive oil, corn oil, grape seed oil, hemp oil, linseed oil, rice oil, safflower oil, sesame oil, mustard oil, and flaxseed oil. Other examples include nut-derived oils, such as oils obtained from beech nuts, cashew nuts, mongo nuts, macadamia nuts, pine nuts, hazelnuts, chestnuts, acorns, almonds, pecans, pistachios, walnuts, or Brazil nuts. As will be appreciated by those skilled in the art, these oils may be produced by any suitable process, such as mechanical extraction (e.g., using an oil mill), chemical extraction (e.g., using solvents such as hexane or carbon dioxide), pressure extraction, distillation, percolation, disintegration, refining, purification, hydrogenation, sparging, and the like.

[0074] Bio-based oils, also referred to as bio-oils, can include oils produced by recombinant cells. For example, recombinantly produced bio-oils can be produced using selected strains of algae cells that are fed a sugar (e.g., sucrose) and fermented to produce a bio-oil with a selected profile. Upon sufficient growth or fermentation, the bio-oil is separated from the cells and collected.

[0075] Generally, the rubber compositions of this invention may contain from about 1 to about 70 parts by weight, or in other embodiments from about 5 to about 50 parts by weight, of total oil per 100 parts by weight of rubber. The amount of sustainable oil may be from about 1% to about 99% by weight, or in other embodiments from about 20% to about 80% by weight, based on the total weight of oil present.

[0076] With respect to waxes, the rubber composition may include one or more sustainable waxes, including natural waxes, or waxes that do not contain petroleum as their source, such as carnauba wax, candelilla wax (e.g., extracted from candelilla flowers), rice wax (e.g., isolated from rice bran oil), and Japan wax (e.g., extracted from wax trees).

[0077] Generally, the rubber compositions of the present invention contain from about 1 to about 20 parts by weight, or in other embodiments from about 2 to about 15 parts by weight, of total waxes per 100 parts by weight of rubber. The amount of sustainable wax may be from about 1% to about 99% by weight, or in other embodiments from about 20% to about 80% by weight of total waxes, based on the total weight of waxes present. In certain embodiments, the rubber compositions contain only sustainable waxes.

[0078] All components of the rubber composition can be mixed using standard mixing equipment, such as a Banbury or Brabender mixer, an extruder, a kneader, and a two-roll mill. In one or more embodiments, the components are mixed in two or more stages. In the first stage (often referred to as the masterbatch mixing stage), a so-called masterbatch (typically containing the rubber component and filler) is prepared. To prevent premature vulcanization (also known as scorch), vulcanizing agents may be omitted from the masterbatch. The masterbatch may be mixed at an initiation temperature of about 25°C to about 125°C and an extrusion temperature of about 135°C to about 180°C. Once the masterbatch is prepared, vulcanizing agents may be introduced and mixed into the masterbatch in a final mixing stage, which is typically performed at a relatively low temperature to reduce the possibility of premature vulcanization. Optionally, an additional mixing stage, often referred to as a re-mill, can be used between the masterbatch mixing stage and the final mixing stage. When silica is included as a filler in the rubber composition, one or more re-mill stages are often used. The addition of various ingredients, including the polymers of the present invention, can occur during these remills.

[0079] Mixing procedures and conditions particularly applicable to silica-filled tire compounds are described in U.S. Patent Nos. 5,227,425, 5,719,207, and 5,717,022, and European Patent No. 890,606, all of which are incorporated herein by reference. In one embodiment, an initial masterbatch is prepared by including the polymer and silica in the substantial absence of coupling and shielding agents.

[0080] To manufacture tire components using the polymers produced by the present invention, those skilled in the art will understand that the polymers are mixed with various other ingredients (e.g., fillers and curatives) to form a rubber composition (also called a vulcanizable composition), which can be processed into tire components according to conventional tire manufacturing techniques, including standard rubber molding, molding, and curing techniques. Typically, vulcanization is accomplished by heating the vulcanizable composition in a mold, which may be heated to, for example, about 140°C to about 180°C. The cured or crosslinked rubber composition may be referred to as a vulcanizate, which generally contains a thermoset three-dimensional polymer network. Other ingredients, such as fillers and processing aids, may be uniformly dispersed throughout the crosslinked network. Pneumatic tires can be manufactured as described in U.S. Pat. Nos. 5,866,171, 5,876,527, 5,931,211, and 5,971,046, which are incorporated herein by reference.

[0081] In one or more embodiments, tires can be constructed by substituting non-petroleum materials for synthetic fibers, such as mechanically recycled fibers, chemically recycled fibers, or bio-based fibers. Similarly, recycled metals can be used to construct tires.

[0082] Various modifications and alterations that do not depart from the scope and spirit of the present invention will be apparent to those skilled in the art. This invention is not to be duly limited to the illustrative embodiments set forth herein. The present application also includes the following aspects. [Section 1] A process comprising: (a) providing a used tire feedstock; (b) gasifying the used tire feedstock to produce a gas stream comprising carbon monoxide, hydrogen, and carbon dioxide; (c) biosynthetically converting at least a portion of the carbon monoxide, hydrogen, and carbon dioxide in the gas stream to produce a first product stream; (d) converting at least a portion of the first product stream to a second product stream comprising acetaldehyde and hydrogen; (e) directing a portion of the hydrogen in the second product stream to biosynthetically converting at least a portion of the carbon monoxide, hydrogen, and carbon dioxide in the gas stream; (f) converting at least a portion of the acetaldehyde to butadiene monomer; The process includes: [Section 2] Item 1. The process of claim 1, wherein the first product stream comprises ethanol. [Section 3] 3. The process of claim 1 or 2, further comprising polymerizing the butadiene monomer into polybutadiene or polybutadiene copolymer. [Section 4] Item 4. The process of any one of items 1 to 3, further comprising manufacturing a tire component using the polybutadiene or polybutadiene copolymer. [Section 5] 5. The process of any one of paragraphs 1 to 4, wherein the step of gasifying comprises gasifying a used tire feedstock and a co-feed comprising a carbonaceous material other than the used tire feedstock. [Section 6] A process comprising: (a) providing a used tire feedstock; (b) optionally providing a co-feed that includes a carbonaceous material other than used tire feedstock; (c) gasifying the used tire feedstock and any co-feed to produce a gas stream comprising carbon monoxide, hydrogen, and carbon dioxide; (d) introducing the gas stream into an aqueous medium, wherein the carbon monoxide, hydrogen, and carbon dioxide are converted into a first product stream; (e) converting the first product stream to a second product stream comprising acetaldehyde and hydrogen; (f) separating said hydrogen from said second product stream, thereby forming a hydrogen stream; (g) converting the acetaldehyde into an end product stream comprising butadiene; A process involving: [Section 7] 7. The process of any one of paragraphs 1 to 6, wherein the first product stream comprises ethanol. [Section 8] 8. The process of any one of paragraphs 1 to 7, wherein the ethanol is converted into the second product stream. [Section 9] 9. The process of any one of paragraphs 1 to 8, further comprising separating the ethanol from the first product stream. [Section 10] 10. The process of any one of paragraphs 1 to 9, further comprising separating the butadiene from the final product stream. [Section 11] 11. The process of any one of paragraphs 1 to 10, wherein the gasifying step is performed by plasma-induced oxidation. [Section 12] Item 12. The process of any one of items 1 to 11, wherein the gas stream is neutralized prior to introducing the gas stream into the aqueous medium. [Section 13] 13. The process of any one of paragraphs 1 to 12, wherein the gas stream is cooled prior to introducing the gas stream into the aqueous medium. [Section 14] 14. The process of any one of paragraphs 1 to 13, wherein the step of introducing the gas stream into the aqueous medium occurs in a bioreactor containing one or more microorganisms for converting the carbon monoxide, hydrogen, and carbon dioxide into the first product stream. [Section 15] 15. The process of any one of paragraphs 1-14, wherein the step of separating the ethanol from the first product stream comprises distilling the ethanol from the first product stream as an overhead stream, and further comprising sending a bottoms stream from the distilling step to a recycle stream. [Section 16] Item 16. The process of any one of items 1 to 15, further comprising introducing the recycle stream into the bioreactor. [Section 17] 17. The process of any one of paragraphs 1 to 16, further comprising introducing the recycle stream into the step of cooling the gas stream. [Section 18] Item 18. The process of any one of items 1 to 17, further comprising introducing the recycled stream into the step of neutralizing the gas stream. [Section 19] 19. The process of any one of paragraphs 1 to 18, further comprising filtering the first product stream prior to converting the first product stream to the second product stream and removing microorganisms from the first product stream. [Section 20] 20. The process of any one of paragraphs 1 to 19, wherein the hydrogen stream is introduced into the aqueous medium. [Section 21] 21. The process of any one of paragraphs 1 to 20, further comprising introducing a second hydrogen stream into the aqueous medium. [Section 22] 22. The process of any one of paragraphs 1 to 21, wherein the step of converting the ethanol to a second product stream occurs in an acetaldehyde reactor, and further comprising introducing a second ethanol stream from an external source into the acetaldehyde reactor. [Section 23] 23. The process of any one of paragraphs 1 to 22, wherein the step of converting the ethanol to acetaldehyde converts greater than 90 mole percent of the ethanol to acetaldehyde and further comprises introducing ethanol into the second product stream prior to the step of converting the acetaldehyde to butadiene. [Section 24] 24. The process of any one of paragraphs 1 to 23, further comprising converting the butadiene to polybutadiene or a butadiene copolymer. [Section 25] 25. The process of any one of paragraphs 1 to 24, further comprising producing a tire material from the polybutadiene or butadiene copolymer. [Section 26] 26. The process of any one of paragraphs 1-25, wherein the step of gasifying includes gasifying the tire feedstock and a co-feed. [Section 27] 27. The process of any one of paragraphs 1 to 26, wherein the co-feed comprises biomass. [Section 28] Item 28. The process of any one of items 1 to 27, wherein the biomass comprises a residue. [Section 29] 29. The process of any one of paragraphs 1 to 28, wherein the residue is a residue of a guayule plant. [Section 30] 30. The process of any one of paragraphs 1 to 29, wherein the tire feedstock and co-feed are mixed to form a mixture prior to the gasifying step. [Section 31] 31. The process of any one of paragraphs 1 to 30, wherein the mixture of used tire feedstock and co-feed contains less than 25 wt. % metals based on the total weight of the mixture. [Section 32] 32. The process of any one of paragraphs 1 to 31, wherein the mixture of used tire feedstock and co-feed comprises less than 5 wt. % fiber yarn or cord based on the total weight of the mixture. [Section 33] 33. The process of any one of paragraphs 1 to 32, wherein the mixture of used tire feedstock and co-feed contains less than 30 wt. % inorganic filler, based on the total weight of the mixture. [Section 34] The mixture has a modulus of 640 kg / m according to ASTM D 698-07 3 Item 34. The process according to any one of items 1 to 33, wherein the compacted density is greater than 1000 MPa. [Section 35] 35. The process of any one of paragraphs 1 to 34, wherein the mixture comprises about 1 to about 75 wt. % co-feed, with the remainder comprising used tires. [Section 36] 36. A vulcanizable composition comprising a polybutadiene or butadiene copolymer prepared by the process according to any one of items 1 to 35. [Section 37] Item 37. The vulcanizable composition according to any one of items 1 to 36, further comprising a filler, an oil, and a rubber curing agent. [Section 38] Item 38. The vulcanizable composition according to any one of items 1 to 37, wherein the filler comprises silica. [Section 39] Item 39. The vulcanizable composition according to any one of items 1 to 38, wherein the filler contains silica derived from rice husk ash. [Section 40] Item 40. The vulcanizable composition according to any one of items 1 to 39, wherein the filler contains recycled carbon black. [Section 41] Item 41. The vulcanizable composition according to any one of items 1 to 40, wherein the oil comprises a bio-oil or a plant-based oil. [Section 42] Item 42. The vulcanizable composition according to any one of items 1 to 41, further comprising a natural wax. [Section 43] 43. The vulcanizable composition of any one of paragraphs 1 to 42, wherein the vulcanizable composition comprises about 30 to about 65 wt. % rubber, based on the total weight of the vulcanizable composition, and more than 10 wt. % of the rubber is polybutadiene or polybutadiene copolymer prepared according to any one of the preceding paragraphs. [Section 44] Item 44. The vulcanizable composition according to any one of items 1 to 43, wherein the vulcanizable composition comprises about 30 to about 150 parts by weight of a filler per 100 parts by weight of rubber, and the filler comprises carbon black and silica in a weight ratio of about 5 to about 99% by weight of the filler. [Section 45] Item 45. The vulcanizable composition according to any one of items 1 to 44, wherein the vulcanizable composition comprises about 1 to about 70 parts by weight of oil per 100 parts by weight of rubber, and at least 1 wt% of the oil is bio-oil or vegetable oil. [Section 46] Item 46. The vulcanizable composition according to any one of items 1 to 45, comprising about 1 to about 20 parts by weight of wax per 100 parts by weight of rubber, wherein at least 1% by weight of the wax is a natural wax. [Section 47] Item 47. A tire component prepared from the vulcanizable composition according to any one of items 1 to 46. [Section 48] Item 48. A tire manufactured by using the tire component according to any one of items 1 to 47. [Section 49] 49. The tire of any one of paragraphs 1 to 48, comprising more than 40% by weight of sustainable materials.

Claims

1. 1. A process for producing butadiene monomer, comprising: (a) providing a used tire feedstock; (b) gasifying the used tire feedstock to produce a gas stream comprising carbon monoxide, hydrogen, and carbon dioxide; (c) biosynthetically converting at least a portion of the carbon monoxide, hydrogen, and carbon dioxide in the gas stream to produce a first product stream; (d) converting at least a portion of the first product stream to a second product stream comprising acetaldehyde and hydrogen; (e) directing a portion of the hydrogen in the second product stream to biosynthetically converting at least a portion of the carbon monoxide, hydrogen, and carbon dioxide in the gas stream; (f) converting at least a portion of the acetaldehyde to butadiene monomer; Including, The process wherein the first product stream comprises ethanol.

2. 10. The process of claim 1, wherein the step of producing the first product stream occurs in a bioreactor containing one or more microorganisms for converting the carbon monoxide, hydrogen, and carbon dioxide into the first product stream.

3. 1. A process for producing butadiene, comprising: (a) providing a used tire feedstock; (b) optionally providing a co-feed comprising a carbonaceous material other than a used tire feedstock; (c) gasifying the used tire feedstock and any co-feed to produce a gas stream comprising carbon monoxide, hydrogen, and carbon dioxide; (d) introducing the gas stream into an aqueous medium, wherein the carbon monoxide, hydrogen, and carbon dioxide are converted into a first product stream; (e) converting the first product stream to a second product stream comprising acetaldehyde and hydrogen; (f) separating the hydrogen from the second product stream, thereby forming a hydrogen stream; (g) converting the acetaldehyde into an end product stream comprising butadiene; Including, the first product stream comprises ethanol; The process wherein the hydrogen stream is introduced into the aqueous medium.

4. 4. The process of any one of claims 1 to 3, wherein the ethanol is converted into the second product stream.

5. 4. The process of claim 3, wherein the step of introducing the gas stream into the aqueous medium occurs in a bioreactor containing one or more microorganisms for converting the carbon monoxide, hydrogen, and carbon dioxide into the first product stream.

6. 4. The process of claim 3 further comprising introducing a second hydrogen stream into the aqueous medium.

7. 5. The process of claim 4, wherein the step of converting the ethanol to the second product stream occurs in an acetaldehyde reactor and further comprises introducing a second ethanol stream from an external source into the acetaldehyde reactor.

8. 4. The process of claim 3 further comprising converting the butadiene to polybutadiene or a butadiene copolymer.

9. The process of any one of claims 1 to 3, wherein the step of gasifying comprises gasifying the tire feedstock and a co-feed.

10. 10. The process of claim 9, wherein the co-feed comprises biomass.

11. The process of claim 10 , wherein the biomass comprises residue.

12. 1. A method for preparing a vulcanizable composition, comprising: Providing a polybutadiene or butadiene copolymer prepared by the process of claim 8; mixing the polybutadiene or butadiene copolymer with a reinforcing filler and a curative; 1. A method for preparing a vulcanizable composition comprising:

13. 1. A method for preparing a tire component, comprising: Providing a vulcanizable composition prepared by the preparation method of claim 12; preparing said tire component using said vulcanizable composition; 1. A method for preparing a tire component, comprising:

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