Systems and methods for catalytic conversion of C1-C5 alcohols to C2-C5 olefin mixtures

Abstract

Methods are provided for converting one or more C1-C5 linear or branched alcohols to one or more C2-C5 olefins. In an exemplary embodiment, the methods can be single-stage processes for directly converting C1-C5 alcohols to a mixture of olefins (e.g., C2-C5) carried out in a single reactor using at least two catalysts physically mixed in a single bed. Systems for carrying out these methods are also provided.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 179,145, entitled "Single Step Conversion of C1-C2 Alcohols to Olefins," filed April 23, 2021, No. 63 / 219,803, entitled "Single Step Conversion of C1-C2 bio-based or petro-based alcohols and mixtures thereof to C2-C7 olefins," filed July 8, 2021, and No. 63 / 316,246, entitled "C2-C5 Olefin Recycle," filed March 3, 2022, which are incorporated by reference in their entireties for all purposes.

[0002] Technical Field A system and method for catalytic conversion of C1-C5 alcohols, more specifically, a catalytic method for the direct conversion of bio-based C1-C5 alcohols to a mixture of olefins (C2-C5) is provided.

[0003] Background technology There is an increasing demand for the use of biomass to partially replace petroleum resources for the synthesis of fuels. Therefore, the use of bioethanol for the synthesis of fuel base stocks is of great interest. The main reaction in the conversion of ethanol to fuel base stocks is the dehydration of ethanol followed by the oligomerization of ethylene.

[0004] In most ethanol dehydration processes, ethanol conversion is nearly complete. Increasing C2 selectivity while maintaining high ethanol conversion is important for process efficiency and to save expensive steps of downstream separation / purification. It is well known that dehydration occurs easily at temperatures above 300°C on acidic solids. The reaction products are mainly water and ethylene, with ethylene being obtained with selectivities as high as 96+%. The most commonly used catalysts are high purity gamma alumina, silica alumina, untreated zeolite (ZSM-5), or zeolite modified by steam treatment. Additionally, the presence of water in the ethanol feed can also have an effect of limiting the deactivation of the catalyst surface.

[0005] U.S. Patent No. 4,302,357 relates to an activated alumina catalyst used in a process for producing ethylene from ethanol by dehydration. In this specification, the LHSV of ethanol is 0.25 to 5 h -1 , preferably 0.5 to 3 hours -1 These examples are for 370°C and 1h -1 The dehydration of an ethanol-water (95 / 5 wt%) mixture over a silica-alumina catalyst in a tubular fixed bed at 315°C to 360°C, 1.7 bar (absolute pressure), and 0.3 h WHSV (on ethanol) is described. The ethanol conversion is 99% and the ethylene selectivity is 94.95%. This is also carried out at an LHSV of 399°C, 1.7 bar (absolute pressure), and 0.7 h WHSV (on ethanol). -1 The dehydration of an ethanol-water (95-75 wt%) mixture over a silica-alumina catalyst in a fluidized bed of WHSV (on ethanol) has also been described. The ethanol conversion is 99.6% and the ethylene selectivity is 99.3%.

[0006] The oligomerization of ethylene requires high pressures, generally in the range of 2-4 MPa, but relatively low temperatures, generally between 20 °C and 200 °C. The catalysts used are most often transition metals deposited on supports of the silica-alumina type, zeolites (ZSM-5), or mesoporous solids (MCM-41), as described by V. Hulea et al., J. Catal., 225 (2004) and Heveling et al., J. Applied Catalysis A: General 174 (1998). However, the direct oligomerization of ethylene requires relatively small amounts (the highest reported levels are about 40%) of C. 10+ Or diesel fraction is obtained. Alternatively, ethylene is converted to C 8+ Oligomerization to olefins can be accomplished via a two-stage process. The first stage involves dimerization of the refined ethylene stream to butenes, followed by dimerization of the butenes to C 8+ The second step is oligomerization to olefins, which after hydrogenation provides fuel base stocks.

[0007] US Patent No. 8,552,241 relates to a process for the conversion of ethanol to diesel fuel base stock in a single step, which involves contacting the ethanol with an acid catalyst at a reaction temperature between 300°C and 500°C. The catalyst used is a 50 / 50 mixture of gamma-alumina in combination with the commercial Axens catalyst "Type IS463", sold as an alumina-based catalyst for the skeletal isomerization of C4 and C5 olefin fractions. A typical single pass product distribution consisted of 40-50% hydrocarbon fraction and 5-20% organic liquid phase yield. The organic liquid phase consists of about 50% olefins, mostly C6 olefins, and about 40% have a boiling point above 150°C, and are therefore compatible with the diesel pool. The 40-50% hydrocarbon gas phase contains mainly ethylene and ethane, as well as traces of C1, C3, C4, and C5. In this case, the yield to the organic liquid phase is relatively low, with about 20% having a boiling point above 150° C. The remaining 80% of the organic liquid and hydrocarbon fraction is primarily ethylene and ethane, with traces of C1, C3, C4, C5, and C6 olefins.

[0008] U.S. Patent No. 9,840,676 relates to a method for converting ethanol in a three-step process into fuels that can be used as full performance or military jet or diesel fuels. However, the process begins with ethylene formation, followed by trimerization to hexene, and finally oligomerization to jet and diesel fractions.

[0009] Thus, there remains a need for improved, efficient and cost-effective catalytic processes for the direct conversion of bio-based alcohols to olefin mixtures.

[0010] Summary of the Invention Embodiments of the present subject matter relate, inter alia, to systems and methods for converting one or more C1-C5 linear or branched alcohols to one or more C2-C5 olefins.

[0011] In an exemplary embodiment, a method for converting one or more C1-C5 linear or branched alcohols to one or more C2-C5 olefins includes contacting an input stream comprising one or more C1-C5 linear or branched alcohols with at least a first catalyst and a second catalyst in a single-bed reactor to form an output stream. The output stream comprises one or more C2-C5 olefins. The single-bed reactor is at a temperature of about 350° C. to about 750° C., a gauge pressure of 0 to about 30 bar, and a weight hourly space velocity (WHSV) of about 0.5 to about 5.0. The first catalyst is a doped or undoped alumina catalyst comprising one or more of zirconium (Zr), titanium (Ti), tungsten (W), or silicon (Si) in neutral or ionic form to form a first mixture, and the second catalyst is a doped or undoped zeolite catalyst.

[0012] In some embodiments, the single-bed reactor can be a fixed-bed reactor. In other embodiments, the single-bed reactor can be a fluidized-bed reactor.

[0013] In some embodiments, contacting the input stream may further include contacting the input stream with a third catalyst in the single-bed reactor. The third catalyst may include a doped or undoped SiO2 catalyst.

[0014] In some embodiments, the C1-C5 linear or branched alcohols may be bio-based and produced by a fermentation process. In some embodiments, the C1-C5 linear or branched alcohols may not be petroleum-derived.

[0015] In some embodiments, the one or more C2-C5 olefins may be present in the output stream in an amount that may be at least 80% by weight, at least 85% by weight, at least 90% by weight, or at least 95% by weight.

[0016] In some embodiments, the output stream comprises one or more aromatics (C 7+In some embodiments, the output stream may contain no more than 10 wt. % of one or more aromatic (C 7+ ) compounds.

[0017] In some embodiments, the method may include removing at least a portion of the C2 olefins from the output stream. In some embodiments, the method may include removing at least a portion of the C4 olefins from the output stream. In some embodiments, the method may include removing at least a portion of the C5 olefins from the output stream.

[0018] In some embodiments, the temperature can be from about 550° C. to about 750° C. In some embodiments, the temperature can be from about 350° C. to about 550° C.

[0019] In some embodiments, the WHSV can be from about 0.5 to about 1.0, In some embodiments, the WHSV can be from about 2.0 to about 5.0.

[0020] In another exemplary embodiment, a method for converting methanol to one or more C2-C5 olefins includes contacting an input stream comprising methanol with at least a first catalyst and a second catalyst in a single-bed reactor to form an output stream. The output stream comprises one or more C2-C5 olefins. The single-bed reactor is at a temperature of about 350° C. to about 750° C., a gauge pressure of 0 to about 30 bar, and a weight hourly space velocity (WHSV) of about 0.5 to about 5.0. The first catalyst is a doped or undoped alumina catalyst comprising one or more of zirconium (Zr), titanium (Ti), tungsten (W), or silicon (Si) in neutral or ionic form, and the second catalyst is a doped or undoped zeolite catalyst.

[0021] In some embodiments, the single-bed reactor can be a fixed-bed reactor. In other embodiments, the single-bed reactor can be a fluidized-bed reactor.

[0022] In some embodiments, contacting the input stream may further include contacting the input stream with a third catalyst in the single-bed reactor. The third catalyst may include a doped or undoped SiO2 catalyst.

[0023] In some embodiments, the C1-C5 linear or branched alcohols may be bio-based and produced by a fermentation process. In some embodiments, the C1-C5 linear or branched alcohols may not be petroleum-derived.

[0024] In some embodiments, the one or more C2-C5 olefins may be present in the output stream in an amount that may be at least 80% by weight, at least 85% by weight, at least 90% by weight, or at least 95% by weight.

[0025] In some embodiments, the output stream comprises one or more aromatics (C 7+ In some embodiments, the output stream may contain no more than 10 wt. % of one or more aromatic (C 7+ ) compounds.

[0026] In some embodiments, the method may include removing at least a portion of the C2 olefins from the output stream. In some embodiments, the method may include removing at least a portion of the C4 olefins from the output stream. In some embodiments, the method may include removing at least a portion of the C5 olefins from the output stream.

[0027] In some embodiments, the temperature can be from about 550° C. to about 750° C. In some embodiments, the temperature can be from about 350° C. to about 550° C.

[0028] In some embodiments, the WHSV can be from about 0.5 to about 1.0, In some embodiments, the WHSV can be from about 2.0 to about 5.0.

[0029] In another exemplary embodiment, a method for converting one or more C1-C5 linear or branched alcohols to one or more C2-C5 olefins includes contacting an input stream comprising one or more C1-C5 linear or branched alcohols with a first catalyst in a stacked bed reactor at a temperature of about 350° C. to about 550° C., a gauge pressure of 0 to about 30 bar, and a weight hourly space velocity (WHSV) of about 1.0 to about 2.0 to form a first mixture. The first catalyst is a doped or undoped alumina catalyst comprising one or more of zirconium (Zr), titanium (Ti), tungsten (W), or silicon (Si) in neutral or ionic form. The method further includes contacting the first mixture with at least a second catalyst in the stacked bed reactor to form an output stream comprising one or more C2-C5 olefins, the second catalyst being a doped or undoped zeolite catalyst.

[0030] In some embodiments, the stacked bed reactor can be a fixed bed reactor. In other embodiments, the stacked bed reactor can be a fluidized bed reactor.

[0031] In some embodiments, contacting the first mixture may further include contacting the first mixture with a third catalyst in a stacked bed reactor. The third catalyst may include a doped or undoped SiO2 catalyst.

[0032] In some embodiments, the C1-C5 linear or branched alcohols may be bio-based and produced by a fermentation process. In some embodiments, the C1-C5 linear or branched alcohols may not be petroleum-derived.

[0033] In some embodiments, the one or more C2-C5 olefins may be present in the output stream in an amount that may be at least 80% by weight, at least 85% by weight, at least 90% by weight, or at least 95% by weight.

[0034] In some embodiments, the output stream comprises one or more aromatics (C7+ In some embodiments, the output stream may contain no more than 10 wt. % of one or more aromatic (C 7+ ) compounds.

[0035] In some embodiments, the method may include removing at least a portion of the C2 olefins from the output stream. In some embodiments, the method may include removing at least a portion of the C4 olefins from the output stream. In some embodiments, the method may include removing at least a portion of the C5 olefins from the output stream.

[0036] In some embodiments, the temperature can be from about 550° C. to about 750° C. In some embodiments, the temperature can be from about 350° C. to about 550° C.

[0037] In some embodiments, the WHSV can be from about 0.5 to about 1.0, In some embodiments, the WHSV can be from about 2.0 to about 5.0.

[0038] In another exemplary embodiment, a method for converting methanol to one or more C2-C5 olefins includes contacting an input stream comprising methanol with a first catalyst in a stacked bed reactor at a temperature of about 350° C. to about 550° C., a gauge pressure of 0 to about 30 bar, and a weight hourly space velocity (WHSV) of about 1.0 to about 2.0 to form a first mixture. The first catalyst comprises a doped or undoped alumina catalyst comprising one or more of zirconium (Zr), titanium (Ti), tungsten (W), or silicon (Si) in neutral or ionic form. The method further includes contacting the first mixture with at least a second catalyst in the stacked bed reactor to form an output stream comprising one or more C2-C5 olefins, wherein the second catalyst is a doped or undoped zeolite catalyst.

[0039] In some embodiments, the stacked bed reactor can be a fixed bed reactor. In other embodiments, the stacked bed reactor can be a fluidized bed reactor.

[0040] In some embodiments, contacting the first mixture may further include contacting the first mixture with a third catalyst in a stacked bed reactor. The third catalyst may include a doped or undoped SiO2 catalyst.

[0041] In some embodiments, the C1-C5 linear or branched alcohols may be bio-based and produced by a fermentation process. In some embodiments, the C1-C5 linear or branched alcohols may not be petroleum-derived.

[0042] In some embodiments, the one or more C2-C5 olefins may be present in the output stream in an amount that may be at least 80% by weight, at least 85% by weight, at least 90% by weight, or at least 95% by weight.

[0043] In some embodiments, the output stream comprises one or more aromatics (C 7+ In some embodiments, the output stream may contain no more than 10 wt. % of one or more aromatic (C 7+ ) compounds.

[0044] In some embodiments, the method may include removing at least a portion of the C2 olefins from the output stream. In some embodiments, the method may include removing at least a portion of the C4 olefins from the output stream. In some embodiments, the method may include removing at least a portion of the C5 olefins from the output stream.

[0045] In some embodiments, the temperature can be from about 550° C. to about 750° C. In some embodiments, the temperature can be from about 350° C. to about 550° C.

[0046] In some embodiments, the WHSV can be from about 0.5 to about 1.0, In some embodiments, the WHSV can be from about 2.0 to about 5.0.

[0047] It should be understood that all combinations of the above concepts and additional concepts discussed in more detail below (provided that such concepts are not mutually inconsistent) are considered to be part of the inventive subject matter disclosed herein. In particular, all combinations of the claimed subject matter of this disclosure are considered to be part of the inventive subject matter disclosed herein. It should also be understood that terms explicitly used in this specification that may also appear in any disclosure incorporated by reference should be given the meaning most consistent with the specific concepts disclosed herein. [Brief description of the drawings]

[0048] [Figure 1] 1 illustrates an exemplary process concept for on-target propylene make-up in a single fixed bed reactor system with closed loop recycle of C2, C4, and C5 olefins consistent with an embodiment of the present subject matter.

[0049] Detailed Description In the following description, certain specific details are described to provide a thorough understanding of various embodiments. However, those skilled in the art will understand that the present disclosure can be practiced without these details. In other instances, well-known structures have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments. Unless otherwise indicated by context, throughout the following specification and claims, the word "comprise" and its variations such as "comprises" and "comprising" should be interpreted in an open and inclusive sense, i.e., "including, but not limited to." Additionally, the headings provided herein are merely for convenience and do not interpret the scope or meaning of the claimed disclosure.

[0050] Throughout this specification, reference to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, although the phrases "in one embodiment" or "in an embodiment" appear in various places throughout this specification, they do not necessarily all refer to the same embodiment. Furthermore, particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Also, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. It should also be noted that the term "or" is generally used in its sense including "and / or" unless the context clearly dictates otherwise.

[0051] The word "about" immediately preceding a numerical value means a range of plus or minus 10% of that value, for example, "about 50" means 45 to 55, "about 25,000" means 22,500 to 27,500, etc. Additionally, the expressions "less than about (value)" or "greater than about (value)" should be understood in light of the definition of the term "about" provided herein.

[0052] "Oxygenates" refer to compounds that contain oxygen in their chemical structure. Examples of oxygenates include, but are not limited to, water, alcohols, esters, and ethers.

[0053] "WHSV" refers to weight hourly space velocity and is defined as the weight of feed flowing per unit weight of catalyst per hour.

[0054] As used herein, "aromatic" or "aromatic compound" refers to cyclic organic carbon compounds of six or more carbons, such as benzene.

[0055] As used herein, "trace amount" or "trace level" refers to a level of less than 2%. In some embodiments, trace amount or trace level may refer to a level of less than about 1.5%, less than about 1%, less than about 0.5%, less than about 0.1%, between about 0.1% and about 1.8%, or between about 1% and about 1.5%.

[0056] "Single stage conversion" refers to a process that occurs in a single reactor system.

[0057] All yields and conversions reported herein are on a weight basis unless otherwise stated.

[0058] It is understood that the examples and embodiments described herein are for illustrative purposes only, and in light thereof, various modifications or changes will occur to those skilled in the art and are to be included within the spirit and scope of this application and the appended claims. All publications, patents, and patent applications cited herein are incorporated by reference in their entirety for all purposes.

[0059] As previously disclosed in WO 2021 / 067294, which is incorporated herein in its entirety, alcohols can be converted to an olefin mixture comprising primarily C3-C7 olefins with low levels of aromatics. This method provides a route to an economical approach for converting alcohols, such as ethanol, into base stocks for the production of fuels. Furthermore, the method described herein can be carried out at lower pressures and higher temperatures with higher yields of olefins compared to already available approaches. This method converts biomass-derived aqueous bioalcohol feedstocks into C3-C7 olefins with high yields. 10+This may involve a single-stage conversion to a higher molecular weight olefin mixture that can be readily oligomerized to hydrocarbon or diesel fractions. Single-stage or two-stage reactor configurations allow the use of specific catalyst systems, which minimize the production of aromatics and thus maximize the production of middle distillates. The method described in WO2021 / 067294 efficiently and economically converts C2-C5 alcohols as fuel base stocks. By converting C2-C5 alcohols to desired fuel product precursors (e.g., C3-C7 olefins) in high yields, processing costs are reduced.

[0060] Aspects of the subject matter disclosed herein improve upon previous approaches by, among other things, providing a method for converting C2-C5 linear or branched alcohols to C2-C7 olefins with low levels of aromatics in high yields at competitive costs using a bicatalyst system. Consistent with the present disclosure, a method for directly converting bio-based C1-C5 alcohols to olefin mixtures (e.g., C2-C5) with low levels of aromatics can be carried out in a single fixed bed reactor. The C2-C5 olefins can be readily oligomerized to base stocks used to produce fuels with high yields.

[0061] In some embodiments, the methods described herein can be carried out in a single bed reactor. In other embodiments, the methods described herein can be carried out in a single stacked bed reactor. For example, in certain embodiments, alcohol, e.g., methanol or ethanol, can be converted to an olefin mixture (e.g., C2-C5) in a single reactor having a first catalyst in an upper section of the reactor and a second catalyst located in a reactor section below the first catalyst. In either a single-stage process (e.g., using a single bed reactor) or a two-stage process (e.g., using a stacked bed reactor), the resulting C2-C5 olefin mixture is suitable for oligomerization into either gasoline, jet, or diesel fuel fractions at relatively low temperatures and pressures, depending on the oligomerization catalyst selected. Furthermore, in some embodiments, the single bed reactor or stacked bed reactor can be defined as a fixed bed reactor, while in other embodiments, a fluidized bed reactor can be used.

[0062] Systems and methods are provided for the catalytic conversion of C1-C5 alcohols. In general, catalytic methods consistent with the present disclosure include alcohol dehydration, followed by accumulation of backbone carbon, and then "cracking" to obtain high yields of low molecular weight olefins (e.g., C2-C5). In this single-stage process, the catalyst mixture can provide a C2-C5 olefin mixture that provides access to low molecular weight olefins in yields with good carbon accountability, as defined by the moles of carbon fed to the system as ethanol and the moles of carbon exiting the system that are incorporated into the C2-C5 olefin mixture. Additionally, the use of a recycle stream of certain olefins (e.g., C2-C5) advantageously provides the ability to maximize the on-target formation of desired olefins, such as propylene, butene, or mixtures thereof. In some embodiments, the mixture of olefins is suitable for oligomerization into either gasoline, jet, or diesel fuel fractions at relatively low temperatures and pressures, depending on the oligomerization catalyst selected.

[0063] As mentioned above, most C2-C5 alcohols are dehydrated in a single unit operation at between 300°C-500°C in the presence of a dehydration catalyst, thereby producing C2-C5 olefins along with water. The water is removed and the C2-C5 olefins are further processed / purified to remove unreacted C2-C5 alcohols and / or impurities before conversion to chemicals and / or fuels. Compared to ethanol (C2 alcohol), the classical approach to convert to chemicals and / or fuels utilizes separate unit operations to achieve i) dehydration to ethylene, ii) ethylene purification followed by dimerization to butenes, iii) cracking to propylene, iv) oligomerization of butenes to unsaturated jet and / or diesel fuel precursors, or v) direct oligomerization of ethylene to unsaturated jet and / or diesel fuel precursors. Similarly, approaches to convert C4 or C5 alcohols to chemicals and / or fuels utilize separate unit operations to accomplish i) dehydration to C4 or C5 olefins, ii) olefin purification to remove oxygenates and / or unreacted alcohol, and iii) oligomerization to unsaturated jet and / or diesel fuel precursors. In comparison to methanol, industrial processes primarily convert coal-derived methanol to olefins over mesoporous catalysts (e.g., SAPO-34, etc.) in a single step with olefin recycle.

[0064] The concept of simultaneously dehydrating, oligomerizing, and cracking C1-C5 alcohols or mixtures thereof in one reactor is difficult due to the high temperatures required for complete dehydration (e.g., about 300° C. to about 500° C.) and the large amount of water present. To achieve a single unit operation capable of simultaneously dehydrating, oligomerizing, and cracking the olefins derived from the dehydration of C1-C5 alcohols, the catalysts used need to be able to withstand high temperatures along with large amounts of water and other oxygenates.

[0065] To address these challenges and define an approach to converting C1-C5 alcohols into viable feedstocks with high yields to fuels, a process has been developed that allows C1-C5 alcohols to be converted in high yields to a mixture of C2-C5 olefins that are readily separable or readily oligomerized in high yields to fuel base stocks via a single unit operation (e.g., a single reactor) for use as chemical feedstocks. As presented herein, the ability to accomplish multiple unit operations and chemical conversions in a single reactor provides practitioners with favorable economics due to reduced fixed and variable costs, lower capital investment, lower energy, and increased productivity.

[0066] To this end, and consistent with the present disclosure, the conversion of methanol, and / or mixtures of methanol and C2-C5 alcohols, as well as C2-C5 olefin mixtures, proceeds with high yields and carbon accountability. Exemplary single reaction steps include i) dehydration, ii) C 4+ iii) backbone rearrangement, and iv) small amounts of C 4+ It involves the cracking of methanol and ethanol primarily to propylene along with olefins and aromatics. Thus, passing a vaporized stream of methanol and ethanol over a single fixed catalyst bed containing a physical mixture containing silicated, zirconated, titanated, niobium, or fluorinated gamma-alumina as the first portion combined with a doped zeolite (boron, phosphorus, or combinations thereof) as the second catalyst portion at between about 300°C and about 450°C results in a mixture of C2-C5 olefins that can be separated for sale or oligomerized "as is" after removal of condensate water to primarily jet and / or diesel fuel. This catalyst combination in a single fixed bed reactor provides i) dehydration, ii) C 4+ iii) skeletal rearrangement, and iv) cracking were achieved, which resulted in longer catalyst time on stream (ToS), improved hydrothermal stability, and improved selectivity to olefins with lower amounts of saturates and aromatics.

[0067] Additionally, the present systems and methods may optionally include recycle of one or more specific olefin fractions (e.g., C2+C4+C5 or C2+C5, etc.) in a closed loop process configuration while simultaneously feeding C1-C5 alcohols. This can maximize the on-target yield of the selected olefins. For example, recycle of the C2+C4+C5 olefin fraction in combination with a co-feed of C1-C5 alcohols using the present systems and methods provided herein unexpectedly resulted in an on-target propylene carbon yield of greater than 80 wt%. Selective recycle of the C2+C5 olefin fraction results in an on-target combined propylene and butene carbon yield of greater than 80 wt%. Example 8 provides further details regarding the unpredictable yields achieved when using recycle of the specific olefin fractions described herein. Additionally, recycle of the C4+C5 olefin fraction can result in an on-target combined ethylene and propylene carbon yield of greater than 80 wt%. An exemplary single step reaction includes i) in situ dehydration, ii) C 3+ iii) backbone rearrangement, and iv) small amounts of C 5+ It may involve cracking to C2-C5 olefins with the formation of olefins and aromatics, thus allowing targeted olefin production for the production of chemicals and / or fuels by recycling selected olefin fractions.

[0068] Unlike the conversion of ethylene, the conversion of propylene and other higher molecular weight olefins (C 4+) can be readily oligomerized over a wide range of catalysts, both zeolitic and non-zeolitic types. The present disclosure enables the ability to convert C1-C5 alcohols to an olefin mixture containing primarily C2-C5 olefins with low levels of aromatics in a single stage or two-stage reactor configuration in series, presenting a route towards an economical method of converting C1-C5 alcohols to chemicals and / or fuel base stocks. The method according to the invention allows aqueous C1-C5 bioalcohol feedstocks obtained from biomass to be separated to isolate the primary low molecular weight olefins used throughout industry as chemical building blocks, or to convert C1-C5 alcohols to C2-C5 olefins in high yields. 10+ A scheme is realised that involves a "single" stage conversion to a mixture of mainly C2-C5 olefins that can be easily oligomerised to hydrocarbon or diesel fractions. A two-stage or single-stage configuration using specific catalyst systems allows minimising the production of aromatics and therefore maximising the production of middle distillates, which is both an asset for ethanol refineries and an advantage from the point of view of sustainable development.

[0069] International patent application WO 2010 / 097175 relates to the direct conversion of alcohols and oxygenates via a two-stage process in which a commercial ZSM-5 zeolite catalyst (Zeolyst CBV-28014) is added to both the first and second stage reactors in series. The first reactor is brought to a temperature of 460°C and the second reactor to a temperature of 320°C. After the temperatures have stabilized, a feed consisting of 86% methanol, 9% isopropanol, and 5% water is started. Single pass conversion of methanol is typically greater than 95% and reported final liquid products are 60-85% C with n>5. n Olefin, n=2-4, 15-40% by weight of light C n The final liquid product is preferably hydrogenated to give a gasoline fraction or oligomerized according to conventional methods to produce a mixture of gasoline, kerosene, and diesel.

[0070] In a single fixed bed reactor configuration, as in the case of C1-C5 alcohols or mixtures thereof, processing costs can be reduced by converting C1-C5 alcohols to desired fuel products or fuel product precursors (e.g., C2-C5 olefins). In one exemplary embodiment, a method for converting one or more C1-C5 linear or branched alcohols to one or more C2-C5 olefins is provided. The method includes contacting an input stream comprising one or more C1-C5 linear or branched alcohols with at least a first catalyst and a second catalyst in a single bed reactor to form an output stream comprising one or more C2-C5 olefins, the single bed reactor being at a temperature of about 350° C. to about 750° C., the gauge pressure being 0 to about 30 bar, and the weight hourly space velocity (WHSV) being about 0.5 to about 5.0.

[0071] Exemplary catalyst combinations physically mixed in a single fixed bed reactor for C2-C5 olefin formation include zeolites doped with a moiety (e.g., first catalyst) such as ZSM-5 (MFI or BEA framework), CHA, FER, FAU, MWW, MOR, EUO, MFS, ZSM-48, MTT, or TON group crystalline silicates having a Si / Al ratio greater than 10; or ZSM5 (MFI or BEA framework), CHA, Dealuminized crystalline silicates of the group FER, FAU, MWW, MOR, EUO, MFS, ZSM-48, MTT, or TON, or phosphorus- and / or boron-modified crystalline silicates of the group ZSM-5 (MFI or BEA framework), CHA, FER, FAU, MWW, MOR, EUO, MFS, ZSM-48, MTT, or TON, having a Si / Al greater than 10, or silicoaluminophosphate type molecular sieves of the group AEL. Additional additives for mixing with the doped zeolite consist of a SiO2 support doped with a metal dopant, including iron (Fe), strontium (Sr), cobalt (Co), nickel (Ni), lanthanum (La), chromium (Cr), zirconium (Zr), ruthenium (Ru), molybdenum (Mo), iridium (Ir), magnesium (Mg), tungsten (W), copper (Cu), manganese (Mn), vanadium (V), zinc (Zn), titanium (Ti), rhodium (Rh), rhenium (Re), gallium (Ga), palladium (Pd), silver (Ag), and indium (In). The second portion of the catalyst mixture (e.g., the second catalyst) may include silicated, zirconated, titanated, niobium, or fluorinated γ-alumina. For example, the aforementioned exemplary catalyst combinations efficiently dehydrate C1-C5 alcohols to their respective olefins, while the doped zeolites result in oligomerization and cracking to C2-C5 olefins with lower amounts of saturates and aromatics compared to literature reports utilizing single component zeolite or metal oxide catalysts.

[0072] The following representative examples are directed to the conversion of C1-C5 alcohols or mixtures thereof to lower amounts of C1-C5 alcohols via a single unit operation with quantitative C1-C5 alcohol conversion. 5+ The present invention relates to the conversion of olefins and aromatics (BTX) to primarily propylene and butenes with a carbon yield of over 85% by weight. In addition, the desired carbon accountability is achieved as further demonstrated by the absence of detectable carbon monoxide or carbon dioxide along with traces of methane. The unreacted olefin fraction (e.g., C2-C5 olefins) can be separated and recycled, resulting in the targeted formation of the desired olefins in high yield and with carbon accountability for the desired olefins.

[0073] Granular or extruded catalysts can be used in the reactions described herein. For example, in some embodiments, the granular or extruded catalysts can have a particle size of at least about 0.05 mm, about 0.1 mm or more, or from about 0.05 mm to about 2.5 mm, including all subranges therebetween. In one embodiment, the granular or extruded catalysts can have a particle size of about 0.4 to about 2.0 mm.

[0074] The present disclosure describes a method for converting one or more C1-C5 linear or branched alcohols to one or more C2-C5 olefins. In certain embodiments, the method includes contacting an input stream comprising one or more C1-C5 linear or branched alcohols with at least a first catalyst and a second catalyst in a single-bed reactor to form an output stream comprising one or more C2-C5 olefins, the single-bed reactor being at a temperature of about 350° C. to about 750° C., a gauge pressure of 0 to about 30 bar, and a weight hourly space velocity (WHSV) of about 0.5 to about 5.0, the first catalyst comprising a doped or undoped alumina catalyst comprising one or more of zirconium (Zr), titanium (Ti), tungsten (W), or silicon (Si) in neutral or ionic form, and the second catalyst comprising a doped or undoped zeolite catalyst.

[0075] The present disclosure also describes a method for converting methanol to one or more C2-C5 olefins. In certain embodiments, the method includes contacting an input stream comprising methanol with at least a first catalyst and a second catalyst in a single-bed reactor to form an output stream comprising one or more C2-C5 olefins. The single-bed reactor operates at a temperature of about 350° C. to about 750° C., a gauge pressure of 0 to about 30 bar, and a weight hourly space velocity (WHSV) of about 0.5 to about 5.0, and the first catalyst includes a doped or undoped alumina catalyst comprising one or more of zirconium (Zr), titanium (Ti), tungsten (W), or silicon (Si) in neutral or ionic form. The second catalyst includes a doped or undoped zeolite catalyst.

[0076] The present disclosure also provides a method for converting one or more C1-C5 linear or branched alcohols to one or more C2-C5 olefins. In certain embodiments, the method may include contacting an input stream comprising one or more C1-C5 linear or branched alcohols with a first catalyst in a stacked bed reactor to form an output stream comprising one or more C2-C5 olefins. The stacked bed reactor has a temperature of about 350° C. to about 550° C., a gauge pressure of 0 to about 30 bar, and a weight hourly space velocity (WHSV) of about 1.0 to about 2.0, and the first catalyst comprises a doped or undoped alumina catalyst comprising one or more of zirconium (Zr), titanium (Ti), tungsten (W), or silicon (Si) in neutral or ionic form. The method further comprises contacting the first mixture with at least a second catalyst, the second catalyst comprising a doped or undoped zeolite catalyst.

[0077] The present disclosure also provides a method for converting methanol to one or more C2-C5 olefins. In certain embodiments, the method includes contacting an input stream comprising methanol with a first catalyst in a stacked bed reactor to form a first mixture. The stacked bed reactor is at a temperature of about 350° C. to about 550° C., a gauge pressure of 0 to about 30 bar, and a weight hourly space velocity (WHSV) of about 1.0 to about 2.0. The first catalyst includes a doped or undoped alumina catalyst comprising one or more of zirconium (Zr), titanium (Ti), tungsten (W), or silicon (Si) in neutral or ionic form to form the first mixture. The first mixture is then contacted with at least a second catalyst to form an output stream comprising one or more C2-C5 olefins, the second catalyst including a doped or undoped zeolite catalyst.

[0078] In some embodiments of the present subject matter, contacting the input stream or the first mixture further comprises contacting the input stream or the first mixture with a third catalyst. The third catalyst can be a doped or undoped SiO2 catalyst. The reactor can be a fixed bed reactor and / or a fluidized bed reactor. Suitable C1-C5 linear or branched alcohols include those that are bio-based and produced by fermentation processes and are not petroleum-derived.

[0079] With respect to the output stream, the C2-C5 olefins may be present in an amount of at least 80% by weight of the output stream. The C2-C5 olefins may be present in an amount of 80% to 99% by weight of the output stream, including all subranges therebetween. The C2-C5 olefins may be present in an amount of at least 85% by weight of the output stream. The C2-C5 olefins may be present in an amount of at least 90% by weight of the output stream. The C2-C5 olefins may be present in an amount of at least 95% by weight of the output stream. Additionally, with respect to the output stream, the methods disclosed herein may further comprise removing at least a portion of the C2 olefins from the output stream. The method may comprise removing at least a portion of the C4 olefins from the output stream. The method may comprise removing at least a portion of the C5 olefins from the output stream.

[0080] With respect to the reactor, the reactor can be operated at a temperature of about 350° C. to about 550° C., including all subranges therebetween. The reactor can be operated at a temperature of about 550° C. to about 750° C., including all subranges therebetween. The reactor can be operated at a WHSV of about 0.5 to about 1.0, including all subranges therebetween. The reactor can be operated at a WHSV of about 2.0 to about 5.0, including all subranges therebetween. The reactor can be a fixed bed reactor. The reactor can be a fluidized bed reactor.

[0081] The following specific examples are intended to illustrate the invention and should not be construed as limiting the scope of the invention as defined by the appended claims.

[0082] The foregoing detailed description has been given merely for clarity of understanding, and no unnecessary limitations should be understood therefrom since modifications will be apparent to those skilled in the art.

[0083] While the invention has been described in relation to particular embodiments thereof, it will be understood that further modifications are possible, and that this application is intended to cover any variations, uses, or adaptations of the invention which generally follow the principles of the invention and include departures from the present disclosure as are known or within customary practice in the art to which the invention pertains, and as may be applied to the essential features set forth above and in the claims that follow.

[0084] Working Example Example 1: Reactor setup Conversion of alcohols (i.e., C1-C5) to C2-C5 olefins was carried out at 300-500 °C through fixed bed reactors containing specific catalysts, where preheated (160 °C) vaporized alcohol was flowed downflow through the fixed catalyst bed with nitrogen co-feed at atmospheric or intermediate pressures (i.e., 0-30 bar). The alcohol flow rate was controlled by a Teledyne Model 500D syringe pump, and the flow rate was adjusted to obtain the target olefin WHSV (weight hourly space velocity). The internal reaction temperature was maintained constant via a Thermo-Scientific Lindberg Blue M furnace. Alcohol conversion and selectivity were calculated from analysis of the liquid-phase reactor effluent by GC for organic and water content, on-line GC analysis of non-condensable hydrocarbons (i.e., C2-C5 olefins), and on-line thermal conductivity detector for quantification of CO, CO2, and CH4 against nitrogen as an internal standard. Thus, passing a vaporized stream of C1-C5 alcohols over a catalyst combination in a single fixed bed reactor at 350°C-450°C results in the formation of C2-C5 olefins in high yields.

[0085] Example 2: Preparation of impregnated Zr-γ-alumina (nominal 5 wt% Zr metal) catalyst Zr-γ-alumina catalyst was prepared by the incipient wetness technique as described. Precursor metal salts (Sigma Aldrich): 2.64 g of zirconium(IV) oxynitrate hydrate was dissolved in deionized water (14.9 mL). After dissolution of the salt, the solution was added dropwise to 15 g of γ-alumina support. The resulting mixed metal oxide was mixed manually to ensure complete wetting, and the resulting impregnated catalyst was dried at 160° C. for 1 h and then calcined at 500° C. for 4 h.

[0086] Example 3: Preparation of boron / phosphorus impregnated ZSM-5 zeolite catalyst Boron and phosphorus impregnated zeolite catalysts were prepared by the incipient wetness technique as described. 0.78 g of phosphoric acid (85%) and 0.96 g of boric acid (99+%) were dissolved in deionized water (7.4 mL). After heating and dissolution, the solution was mixed with 6 g of ZSM-5 zeolite support (i.e., Zeolyst type CBV-5524 H + The resulting impregnated catalyst was dried at 160°C for 1 hour and then calcined at 550°C for 3 to 15 hours.

[0087] Example 4: Single stage reactor Single stage reactor configuration: Reaction conditions: T=355° C., WHSV=2.5 (methanol based), P=0 bar in the reactor; Catalyst—zirconated (4.0 wt.%) γ-alumina physically mixed with doped ZSM-5 zeolite.

[0088] [Table 1]

[0089] Ethylene conversion with a mass yield of approximately 68%

[0090] Example 5: Single stage reactor Single stage reactor configuration: Reaction conditions: T=425°C, WHSV=4.5 (ethanol based), P=0 bar in the reactor; Catalyst—zirconated (4.0 wt%) γ-alumina physically mixed with doped ZSM-5 zeolite and Ni-doped SiO2.

[0091] [Table 2]

[0092] Ethylene conversion with a mass yield of approximately 62%

[0093] Example 6: Single stage reactor Single stage reactor configuration: Reaction conditions: Feed preheater T = 160 °C, reactor T = 445 °C, total WHSV = 3.4 (including recycle), P = 0-1 bar; Catalyst: Zirconated (4.0 wt%) γ-alumina physically mixed with doped ZSM-5 zeolite; Feed composition: hydrous ethanol (92%) = 0.15 ml / min, ethylene recycle = 70 ml / min (0.087 g / min); mixed butenes = 23 ml / min (0.057 g / min), mixed pentenes = 0.035 ml / min, nitrogen = 10 ml / min.

[0094] [Table 3]

[0095] [Table 4]

[0096] The process concept and material balance of on-target propylene (81% yield) formation with closed loop recycle of C2, C4, and C5 olefins based on the experimental data from Example 6 is shown in FIG. 1. The recycle of C2, C4, and C5 olefins maximizes on-target olefin formation. FIG. 1 shows a single stage reactor system 1000. As shown in the figure, an input 100, such as aqueous ethanol (92%), can be fed to a fixed bed reactor 300 to produce an output 200, such as a C2-C5 olefin mixture with a final output given in Table 4 above. Additionally, recycle streams R1, R2, and R3 can recycle C2, C4, and C5 olefins back to the input 100 and fed back to the fixed bed reactor 300, respectively. Wastewater 400 can also be produced in situ by the fixed bed reactor 300 via dehydration of ethanol to ethylene, and thus can be condensed and removed as part of the output 200.

[0097] Example 7: Simultaneous dehydration, dimerization, skeletal rearrangement, and cracking of C1-C5 bio-based or petroleum-based alcohols and their mixtures to C2-C7 olefins The purpose of this example is to provide data showing the conversion of C1-C5 bio-based or petroleum-based alcohols to a mixture of C2-C7 olefins with low levels of aromatics. Details of the reactor set-up and resulting effluent streams, as well as yield data, are provided below.

[0098] Single stage reactor configuration: Reaction conditions: T=425°C, WHSV=4.5 (ethanol based), P=0 bar in the reactor; Catalyst—zirconated (4.0 wt%) γ-alumina physically mixed with doped ZSM-5 zeolite and Ni-doped SiO2.

[0099] [Table 5]

[0100] Ethylene conversion with a mass yield of approximately 62%

[0101] Example 8: Increased propylene yield using recycle of olefin fraction Provided herein is data showing increased yields using recycle of the C2 / C3 / C4 olefin fraction as disclosed herein.

[0102] Single stage reactor configuration for data in Table 6: Reaction conditions: Feed preheater T = 160 °C, reactor T = 445 °C, total WHSV = 4.35, P = 0-1 bar; Catalyst: zirconated (4.0 wt%) γ-alumina.

[0103] [Table 6]

[0104] Single stage reactor configuration for data in Table 7: Reaction conditions: Feed preheater T = 160 °C, reactor T = 445 °C, total WHSV = 3.7 (including recycle), P = 0-1 bar; Catalyst: zirconated (4.0 wt%) γ-alumina.

[0105]

Table 7

Claims

1. Methanol and one or more C2-C ５ Linear or branched alcohol is one or more C ２ ~C ５ 1. A process for converting a hydrocarbon to an olefin, comprising the steps of: The methanol and one or more C2-C ５ An input stream comprising linear or branched alcohols is contacted in a single bed reactor with at least a first catalyst and a second catalyst to produce said one or more C ２ ~C ５ forming an output stream comprising olefins, wherein the single bed reactor is at a temperature of from 350° C. to 750° C., has a gauge pressure of from 0 to 30 bar, and has a weight hourly space velocity (WHSV) of from 0.5 to 5.0; The first catalyst comprises a doped or undoped alumina catalyst containing one or more of zirconium (Zr), titanium (Ti), tungsten (W), or silicon (Si) in neutral or ionic form to form a first mixture, and the second catalyst comprises a doped or undoped zeolite catalyst; method.

2. 2. The process of claim 1, wherein the single bed reactor is a fixed bed reactor or a fluidized bed reactor.

3. 3. The process of claim 1 or 2, wherein contacting the input stream further comprises contacting the input stream with a third catalyst in the single-bed reactor.

4. The third catalyst is doped or undoped SiO ２ The method of claim 3 including a catalyst.

5. C １ ~C ５ 3. The method of claim 1 or 2, wherein the linear or branched alcohol is bio-based and produced by a fermentation process.

6. C １ ~C ５ 3. The method of claim 1 or 2, wherein the linear or branched alcohol is not derived from petroleum.

7. The one or more C ２ ~C ５ 3. The process of claim 1 or 2, wherein olefins are present in the output stream in an amount of at least 80 wt%, at least 85 wt%, at least 90 wt%, or at least 95 wt%.

8. 5. The output stream comprises one or more aromatics (C ７＋ 3. The method of claim 1 or 2, comprising the compound.

9. 5. The method of claim 4, further comprising the step of: ７＋ 3. The method of claim 1 or 2, comprising the compound.

10. The method further comprises the step of: ２ 3. The process of claim 1 or 2, further comprising removing a portion of the olefin.

11. The method further comprises the step of: ４ 3. The process of claim 1 or 2, further comprising removing a portion of the olefin.

12. The method further comprises the step of: ５ 3. The process of claim 1 or 2, further comprising removing a portion of the olefin.

13. The method of claim 1 or 2, wherein the temperature is between 550°C and 750°C.

14. The method of claim 1 or 2, wherein the temperature is between 350°C and 550°C.

15. 3. The method of claim 1 or 2, wherein the WHSV is from 0.5 to 1.0, or from 2.0 to 5.0.

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