Selective hydrogenolysis coupled with MTBE production

Abstract

A method for producing methyl tert-butyl ether (MTBE) comprises: introducing a butane feed stream (n-butane, isobutane) and hydrogen into a hydrogenolysis reactor comprising a hydrogenolysis catalyst to produce a hydrogenolysis product stream comprising hydrogen, methane, ethane, propane, isobutane and optionally n-butane; separating the hydrogenolysis product stream into a first hydrogen-containing gas stream, an optional methane stream, a C2 to C3 gas stream (ethane, propane) and a butane stream (isobutane, optionally n-butane); feeding the butane stream to a dehydrogenation reactor to produce a dehydrogenated product stream, wherein the dehydrogenation reactor comprises a dehydrogenation catalyst and wherein the dehydrogenated product stream comprises hydrogen, isobutane and isobutylene; and feeding the dehydrogenated product stream and methanol to an etherification unit to produce an unreacted methanol stream, an unreacted isobutylene stream and an MTBE stream.

Description

Technical Field

[0001] The present disclosure relates to a process for producing methyl tert-butyl ether (MTBE), and more particularly to a process for producing methyl tert-butyl ether (MTBE) in conjunction with butane hydrogenolysis. Background Art

[0002] Methyl tertiary butyl ether (MTBE) is a fuel additive (e.g., oxygenated additive) used as gasoline and a compound used as a solvent. MTBE is usually produced by methanol and isobutene. The conventional method for MTBE production can be started by a plant-level (field-grade) butane stream containing normal butane and isobutane simultaneously, wherein the plant-level butane stream is isomerized to convert normal butane into isobutane. However, such conversion is incomplete, and a separation step is required after isomerization to separate the isomerized product stream into an isobutane-rich stream and a normal butane-rich stream. The isobutane-rich stream can be sent to dehydrogenation to produce isobutene, and isobutene can be fed to the MTBE reactor to produce MTBE. Isomerization and separation steps require a large amount of funds and energy. Therefore, there is an urgent need to develop a method for producing MTBE by a plant-level butane stream. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] In order to describe in detail the preferred aspects of the disclosed method, reference will now be made to the accompanying drawings, in which:

[0004] Figure 1 shows the configuration of a methyl tert-butyl ether (MTBE) production system; and

[0005] Figure 2 Another configuration of an MTBE production system is shown. DETAILED DESCRIPTION

[0006] Disclosed herein is a method of combining a butane hydrogenolysis reactor with a dehydrogenation reactor and an etherification unit for producing methyl tertiary butyl ether (MTBE), wherein the feed stream of the method comprises a mixed butane stream (e.g., plant-grade butane). Typically, the plant-grade butane stream comprises a mixture of normal butane and isobutane; for example, about 60mol% to about 75mol% of normal butane and about 25mol% to about 40mol% of isobutane. By using a hydrogenolysis catalyst in a hydrogenolysis reactor, the plant-grade butane stream can be reactively separated by selectively reacting the normal butane from the plant-grade butane stream. The hydrogenolysis reactor can convert normal butane into a gas stream of methane, ethane, and propane (mainly ethane; specifically, more ethane than a hydrocracking reactor in the case of cracking the same amount of normal butane). Hydrogen can be fed to the hydrogenolysis reactor together with the plant-grade butane stream. The hydrogenolysis catalyst may comprise a variety of monometallic catalysts (e.g., Pt or Ir supported on alumina, and / or Pt or Ir supported on ZSM-5) and / or bimetallic catalysts (e.g., Pt or Ir supported on alumina, and / or Pt and Ir supported on ZSM-5).

[0007] Typically, isobutane is minimally converted in the hydrogenolysis reactor (e.g., the hydrogenolysis reactor may be characterized by an isobutane conversion of less than about 25%). The hydrogenolysis reaction may be carried out at operating parameters (e.g., catalyst, pressure, temperature, flow rate, etc.) that effectively limit (e.g., minimize, reduce, etc.) the conversion of isobutane, thereby resulting in a high selectivity to ethane. Without wishing to be limited by theory, when isobutane is converted, typically 1 mole of isobutane is converted to 1 mole of methane and 1 mole of propane (i.e., no ethane); and by avoiding or minimizing the isobutane conversion, the overall ethane selectivity may be increased. In addition, n-butane is typically almost completely converted in the hydrogenolysis reactor (i.e., the n-butane conversion in the hydrogenolysis reactor is maximized); for example, the hydrogenolysis reactor may be characterized by an n-butane conversion of greater than about 90%. The hydrogenolysis reaction may be carried out at operating parameters that effectively maximize (e.g., improve, increase, etc.) the conversion of n-butane, thereby resulting in a high selectivity to ethane. Without wishing to be limited by theory, when n-butane is converted, typically 1 mole of n-butane is converted to 2 moles of ethane; and by maximizing n-butane conversion, the overall ethane selectivity can be increased. The method for producing olefins as disclosed herein can maximize the production of ethane in the hydrogenolysis reaction. As will be appreciated by those skilled in the art, and with the aid of this disclosure, the amount of ethane produced and / or the selectivity for ethane are reduced in the hydrogenolysis reactor, respectively, due to an undesirable reduction in the conversion of n-butane in the hydrogenolysis reactor and / or due to an undesirable conversion of more isobutane in the hydrogenolysis reactor.

[0008] The isobutane recovered from the hydrogenolysis reactor can be fed to a dehydrogenation reactor, wherein the isobutane can be converted into a mixture of isobutene and hydrogen. Hydrogen can be introduced into the hydrogenolysis reactor. Isobutene can react with methanol to produce MTBE. The ethane and / or propane produced in the hydrogenolysis reactor can be further sent to a steam cracking furnace to produce ethylene and / or propylene.

[0009] Except as otherwise indicated in the operating examples or otherwise, all numerical values ​​or expressions used in the specification and claims involving the quantity of ingredients, reaction conditions, etc. are to be understood as being modified by the term "about" in all cases. Various numerical ranges are disclosed herein. Because these ranges are continuous, they include each value between the minimum and maximum values. The endpoints of all ranges recording the same property or component can be independently combined and include the listed endpoints. Unless otherwise expressly stated, the various numerical ranges specified in this application are approximate values. The endpoints of all ranges involving the same component or attribute include the endpoint and can be independently combined. The term "from greater than 0 to a certain amount" refers to the presence of a certain amount of a specified component greater than 0 and up to a higher specified amount and including a higher specified amount.

[0010] The terms "an," "a," and "the" do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. As used herein, the singular forms "an," "a," and "the" include plural referents.

[0011] As used herein, "a combination thereof" includes one or more of the elements described, optionally together with similar elements that are not listed, for example, including one or more specified components, optionally in combination with one or more other components having substantially the same function, not explicitly specified. As used herein, the term "combination" includes blends, mixtures, alloys, reaction products, and the like.

[0012] References throughout the specification to "on one hand," "on the other hand," "other aspects," "some aspects," etc., mean that a particular element (e.g., feature, structure, attribute, and / or characteristic) described in conjunction with that aspect is included in at least one aspect described herein, and may or may not be present in other aspects. In addition, it should be understood that one or more of the described elements may be combined in any suitable manner in the various aspects.

[0013] As used herein, the terms "inhibit" or "reduce" or "prevent" or "avoid" or any variation of these terms includes any measurable decrease or complete inhibition to achieve the desired result.

[0014] As used herein, the term "effective" means sufficient to accomplish a desired, expected, or intended result.

[0015] As used herein, the terms "comprising" (and any form of comprising, such as "comprise" and "comprises"), "having" (and any form of having, such as "have" and "has"), "including" (and any form of including, such as "include" and "includes"), or "containing" (and any form of containing, such as "contain" and "contains") are inclusive or open-ended, and do not exclude additional, unrecited elements or method steps.

[0016] Unless defined otherwise, technical and scientific terms used in the present disclosure have the same meanings as commonly understood by those skilled in the art.

[0017] Standard terminology is used herein to describe compounds. For example, any position not substituted by any specified group is understood to have its valency filled by a specified bond or hydrogen atom. A dash ("-") that is not between two letters or symbols is used to indicate the point of attachment of a substituent. For example, -CHO is attached through the carbon of the carbonyl group.

[0018] As used herein, the term “C x Hydrocarbons" and "C xs " are interchangeable and refer to any hydrocarbon having x carbon atoms (C). For example, the terms "C4 hydrocarbon" and "C 4s ” refers to any hydrocarbon having exactly four carbon atoms, such as n-butane, isobutane, cyclobutane, 1-butene, 2-butene, isobutene, butadiene, etc., or combinations thereof.

[0019] As used herein, the term “C x+ A "hydrocarbon" refers to any hydrocarbon having equal to or greater than x carbon atoms (C). For example, the term "C 2+ "Hydrocarbon" refers to any hydrocarbon having 2 or more carbon atoms, such as ethane, ethylene, C3, C4, C5, etc.

[0020] refer to Figure 1 , discloses a methyl tert-butyl ether (MTBE) production system 1000. The MTBE production system 1000 generally includes: a hydrogenolysis reactor 100; a first separation unit 200; a dehydrogenation reactor 300; and an etherification unit 400.

[0021] refer to Figure 2, discloses an MTBE production system 2000. The MTBE production system 2000 generally includes: a hydrogenolysis reactor 100; a first separation unit 200; a dehydrogenation reactor 300; a second separation unit 350; and an etherification unit 400. As will be appreciated by those skilled in the art, and with the aid of this disclosure, Figure 1 and Figure 2 The MTBE production system components shown in the drawings may be in fluid communication with each other (as represented by connecting lines indicating the direction of fluid flow) by any suitable conduits (e.g., pipes, flow channels, etc.). Unless otherwise indicated, the same reference numerals refer to the same components present in one or more of the drawings, and the description of a particular component generally applies to the respective drawing in which the component is present.

[0022] In one aspect, the method for producing MTBE disclosed herein may include introducing a butane feed stream 10 and hydrogen 15 into a hydrogenolysis reactor 100 to produce a hydrogenolysis product stream 20, wherein the hydrogenolysis reactor 100 comprises a hydrogenolysis catalyst, wherein the butane feed stream 10 comprises normal butane and isobutane, and wherein the hydrogenolysis product stream 20 comprises hydrogen, methane, ethane, propane, isobutane, and optionally normal butane. In some aspects, the hydrogenolysis product stream 20 may also comprise some impurities, such as C 5+ In some aspects, hydrogenolysis product stream 20 is substantially free of n-butane.

[0023] In general, hydrogenolysis refers to a chemical reaction in which a carbon-carbon or carbon-heteroatom single bond is broken or "cracking" by hydrogen, usually at relatively low temperatures (e.g., below about 330°C). For the purposes of this disclosure, the term "selective hydrogenolysis" refers to a hydrogenolysis process in which two or more different hydrocarbons (e.g., a first hydrocarbon, a second hydrocarbon; n-butane, isobutane) undergo a hydrogenolysis reaction, and at least one hydrocarbon (e.g., a first hydrocarbon; n-butane) undergoes hydrogenolysis, and at least one hydrocarbon (e.g., a second hydrocarbon; isobutane) is resistant to hydrogenolysis (e.g., having a low conversion in the hydrogenolysis reaction, such as a conversion of less than about 25%) under the same given set of reaction conditions (e.g., catalyst, pressure, temperature, flow rate, etc.). In general, the conversion of a reagent or reactant refers to the percentage (usually mol%) of a reagent that reacts with an undesirable product and a desired product based on the total amount (e.g., moles) of the reagent present before any reaction occurs. For the purposes of this disclosure, the conversion of a reagent is the conversion % based on the number of moles converted. Without wishing to be limited by theory, the hydrogenolysis reaction rate of the first hydrocarbon (e.g., n-butane) is greater than the hydrogenolysis reaction rate of the second hydrocarbon (e.g., isobutane), thereby allowing the separation (e.g., reactive separation) of n-butane and isobutane by consuming n-butane in the hydrogenolysis reaction and recovering unreacted isobutane. As will be appreciated by those skilled in the art, and with the benefit of this disclosure, the selective hydrogenolysis of n-butane from a butane feed stream (e.g., butane feed stream 10) comprising n-butane and isobutane provides a reactive separation of n-butane from isobutane.

[0024] In one aspect, the butane feed stream 10 may comprise normal butane and isobutane. In some aspects, the butane feed stream 10 may comprise normal butane in an amount equal to or greater than about 5 mol%, or equal to or greater than about 10 mol%, or equal to or greater than about 20 mol%, or equal to or greater than about 30 mol%, or equal to or greater than about 40 mol%, or equal to or greater than about 50 mol%, or equal to or greater than about 60 mol%, or equal to or greater than about 70 mol%, or equal to or greater than about 80 mol%, or equal to or greater than about 90 mol%.

[0025] The butane feed stream 10 may contain equal to or greater than about 5 mol%, or equal to or greater than about 10 mol%, or equal to or greater than about 20 mol%, or equal to or greater than about 30 mol%, or equal to or greater than about 40 mol%, or equal to or greater than about 50 mol%, or equal to or greater than about 60 mol%, or equal to or greater than about 70 mol%, or equal to or greater than about 80 mol%, or equal to or greater than about 90 mol% of isobutane.

[0026] In one aspect, butane feed stream 10 can be characterized by a molar ratio of n-butane to isobutane of equal to or greater than about 0.05:1, or equal to or greater than about 0.1:1, or equal to or greater than about 0.25:1, or equal to or greater than about 0.5:1, or equal to or greater than about 1:1, or equal to or greater than about 2:1, or equal to or greater than about 2.5:1, or equal to or greater than about 5:1, or equal to or greater than about 7.5:1, or equal to or greater than about 10:1, or from about 0.05:1 to about 10:1, or from about 0.1:1 to about 7.5:1, or from about 0.25:1 to about 5:1, or from about 0.5:1 to about 2.5:1.

[0027] In one aspect, butane feed stream 10 can comprise equal to or greater than about 50 mol% n-butane. In this aspect, butane feed stream 10 can comprise less than about 50 mol% isobutane.

[0028] In one aspect, butane feed stream 10 may include plant-grade butane (e.g., mixed butane). Plant-grade butane is typically produced by natural gas processing and / or oil refining. Plant-grade butane may include: about 50 mol% to about 80 mol%, or about 55 mol% to about 80 mol%, or about 60 mol% to about 75 mol% of normal butane; and about 20 mol% to about 50 mol%, or about 20 mol% to about 45 mol%, or about 25 mol% to about 40 mol% of isobutane. Plant-grade butane may also include about 0 mol% to about 5 mol% of propane and / or pentane. In some aspects, plant-grade butane may be characterized by a molar ratio of about 1:1 to about 4:1, or about 1.2:1 to about 4:1, or about 1.5:1 to about 3:1 of normal butane to isobutane.

[0029] In one aspect, the hydrogenolysis reactor 100 can include a fixed bed reactor, a radial flow reactor, a multi-layer bed reactor, a continuous flow reactor, an adiabatic reactor, an isothermal reactor, the like, or a combination thereof.

[0030] In one aspect, the hydrogenolysis reactor 100 can be characterized by a temperature (e.g., hydrogenolysis temperature) of about 200° C. to about 330° C., or about 250° C. to about 325° C., or about 280° C. to about 310° C. As will be appreciated by those skilled in the art, and with the benefit of this disclosure, temperatures below 330° C. favor selective hydrogenolysis. In contrast to hydrogenolysis, hydrocracking refers to a process of rearranging and breaking hydrocarbon chains and adding hydrogen to unsaturated hydrocarbons to produce saturated hydrocarbons at relatively high temperatures (e.g., greater than about 330° C.).

[0031] As will be appreciated by those skilled in the art, and with the aid of this disclosure, and without wishing to be limited by theory, given the same feed stream, hydrogenolysis and hydrocracking will produce different product distributions due to different reaction mechanisms (which may activate or inhibit different components of a given catalyst). For example, relatively high temperatures (e.g., hydrocracking temperatures, such as greater than about 400°C) may deactivate one of the metals of the hydrogenolysis catalyst (e.g., the metal of the hydrogenolysis bimetallic supported catalyst, such as Ir), thereby promoting cracking and hydrogenation of all components of the feed stream (e.g., n-butane and isobutane) in the presence of the partially deactivated hydrogenolysis catalyst. In addition, as will be appreciated by those skilled in the art, and with the aid of this disclosure, and without wishing to be limited by theory, relatively high temperatures (e.g., hydrocracking temperatures, such as greater than about 400°C) are generally required to overcome the activation energy to initiate cracking. Furthermore, as will be appreciated by those skilled in the art, and with the aid of this disclosure, and without wishing to be limited by theory, branched chain isobutane is a more stable molecule than straight chain n-butane, and such higher temperatures (e.g., greater than about 400° C.) are generally required to activate the isobutane in the cracking process.

[0032] In one aspect, hydrogenolysis of butane feed stream 10 at relatively low temperatures (e.g., less than about 330° C.) can increase the amount of ethane in hydrogenolysis product stream 20 as compared to the amount of ethane in the product stream obtained by otherwise similar processes operating at relatively higher temperatures (e.g., greater than about 330° C.).

[0033] As will be appreciated by those skilled in the art, and with the aid of this disclosure, hydrocracking of a butane feed stream at relatively high temperatures (e.g., greater than about 330° C.) can increase the amount of propane and / or methane, respectively, as compared to the amount of propane and / or methane in a product stream obtained from an otherwise similar process (e.g., a hydrogenolysis process) operating at relatively low temperatures (e.g., less than about 330° C.). In addition, as will be appreciated by those skilled in the art, and with the aid of this disclosure, and without wishing to be limited by theory, hydrocracking follows a different reaction mechanism or pathway than hydrogenolysis, which results in an increase in the amount of propane in hydrocracking compared to hydrogenolysis.

[0034] Hydrogenolysis reactor 100 can be characterized by a pressure (e.g., hydrogenolysis pressure) from about 0 psig to about 300 psig, or from about 10 psig to about 300 psig, or from about 20 psig to about 200 psig, or from about 50 psig to about 150 psig, or from about 75 psig to about 125 psig, or from about 90 psig to about 110 psig.

[0035] The hydrogenolysis reactor 100 may be characterized by a -1 About 15h -1 , or about 0.5h-1 About 10 hours -1 , or about 1h -1 About 5 hours -1 The hydrocarbon-based weight hourly space velocity (WHSV). In general, WHSV refers to the mass of reagent (e.g., hydrocarbon) fed per hour divided by the mass of catalyst used in a particular reactor.

[0036] The hydrogenolysis reactor 100 may be characterized by a molar ratio of hydrogen to C4 hydrocarbons of from about 1:1 to about 10:1, or from about 1.5:1 to about 7.5:1, or from about 2:1 to about 5:1.

[0037] In some aspects, the hydrogenolysis reactor 100 can be operated at a set of optimal operating parameters that result in substantially consuming all of the n-butane in the hydrogenolysis reactor 100, wherein the hydrogenolysis product stream 20 is substantially free of n-butane (and thus the butane stream 30 is substantially free of n-butane). As will be appreciated by those skilled in the art, and with the benefit of the present disclosure, reactor parameters affect reaction rates (e.g., the rate at which reactants such as n-butane and isobutane are consumed) in an interdependent manner; for example, reaction temperature (e.g., hydrogenolysis reaction temperature) and WHSV affect the reaction rates for n-butane and isobutane in a hydrogenolysis reactor (e.g., hydrogenolysis reactor 100) in an interdependent manner. In one aspect, to substantially consume all of the n-butane in the hydrogenolysis reactor 100, the hydrogenolysis reactor 100 can be operated (e.g., maintained at) a temperature of about 280° C. to about 300° C. for the following parameters. For example, to substantially consume all of the n-butane in the hydrogenolysis reactor 100, the hydrogenolysis reactor 100 can be operated at a temperature of about 280° C. to about 300° C. for about 0.1 h. -1 About 5 hours -1 % to about 0.4 wt %, or about 0.3 wt %, based on the total weight of the hydrogenolysis bimetallic supported catalyst; wherein the total amount of Ir present is from about 0.2 wt % to about 0.4 wt %, or about 0.3 wt %, based on the total weight of the hydrogenolysis bimetallic supported catalyst; wherein the Pt and Ir are present in a weight ratio of Pt to Ir of from about 0.8:1 to about 1.2:1, or about 1:1; and wherein the ZSM-5 is characterized by a weight ratio of silica to alumina (SiO2 / Al2O3) of from about 250 to about 300, or about 280.

[0038] In one aspect, the hydrogenolysis reactor 100 may include a hydrogenolysis catalyst. In some aspects, the hydrogenolysis catalyst may include a hydrogenolysis monometallic supported catalyst, such as a zeolite-supported monometallic catalyst and / or an alumina-supported monometallic catalyst. In other aspects, the hydrogenolysis catalyst may include a hydrogenolysis bimetallic supported catalyst, such as a zeolite-supported bimetallic catalyst and / or an alumina-supported bimetallic catalyst. In other aspects, the hydrogenolysis catalyst may include a hydrogenolysis monometallic supported catalyst and a hydrogenolysis bimetallic supported catalyst.

[0039] In some aspects, the hydrogenolysis bimetallic supported catalyst disclosed herein may comprise a first metal, a second metal, and a support; and wherein the first metal is different from the second metal. In other aspects, the hydrogenolysis monometallic supported catalyst disclosed herein may comprise a third metal and a support. In some aspects, the third metal may be the same as the first metal or the second metal. In other aspects, the third metal may be different from the first metal and / or the second metal.

[0040] In one aspect, the first metal, the second metal and the third metal can each be independently selected from the group consisting of iridium (Ir), platinum (Pt), rhodium (Rh), ruthenium (Ru), palladium (Pd), molybdenum (Mo), tungsten (W), nickel (Ni) and cobalt (Co).

[0041] In one aspect, the first metal, the second metal, and the third metal can each independently be one or more metals from Group 6 of the Periodic Table; one or more metals from Group 8 of the Periodic Table; one or more metals from Group 9 of the Periodic Table; one or more metals from Group 10 of the Periodic Table; or combinations thereof; wherein the first metal is different from the second metal; and wherein the third metal is the same as or different from the first metal and / or the second metal.

[0042] In some aspects, the first metal comprises Pt and the second metal comprises Ir. In other aspects, the first metal comprises Pt and the second metal comprises Rh. In other aspects, the first metal comprises Pt and the second metal comprises Ir and Rh.

[0043] In some aspects, the third metal can include Pt, Ir, or Rh.

[0044] In one aspect, the first metal and the second metal can be present in the hydrogenolysis bimetallic supported catalyst in a weight ratio of first metal to second metal of about 0.1:1 to about 10:1, or about 0.5:1 to about 7:1, or about 1:1 to about 4:1, or about 0.3:1 to about 3:1, or about 0.5:1 to about 2:1, or about 0.7:1 to about 1.5:1, or about 0.8:1 to about 1.2:1.

[0045] In one aspect, the total amount of the first metal and the second metal present in the hydrogenolysis bimetallic supported catalyst (i.e., the amount of the first metal + the amount of the second metal) can be from about 0.1 wt% to about 10 wt%, or from about 0.15 wt% to about 5 wt%, or from about 0.2 wt% to about 1 wt%, or from about 0.4 wt% to about 0.8 wt%, or from about 0.5 wt% to about 0.7 wt%, based on the total weight of the hydrogenolysis bimetallic supported catalyst.

[0046] In one aspect, the third metal may be present in the hydrogenolysis monometallic supported catalyst in a total amount of about 0.1 wt % to about 10 wt %, or about 0.15 wt % to about 5 wt %, about 0.2 wt % to about 1 wt %, or about 0.4 wt % to about 0.8 wt %, or about 0.5 wt % to about 0.7 wt %, based on the total weight of the hydrogenolysis monometallic supported catalyst.

[0047] In one aspect, supports suitable for use in the hydrogenolysis catalysts of the present invention may include alumina and / or zeolites.

[0048] In some aspects, the carrier suitable for the hydrogenolysis catalyst of the present invention can be composed of alumina and / or zeolite or consist essentially of alumina and / or zeolite. In other aspects, the carrier suitable for the hydrogenolysis catalyst of the present invention can include alumina and / or zeolite, and a binder. Typically, the binder can be used to improve the mechanical properties of the carrier (e.g., to improve wear resistance). Non-limiting examples of binders suitable for the hydrogenolysis catalyst disclosed herein include alumina, titania, silica, etc., or a combination thereof.

[0049] In one aspect, the hydrogenolysis catalyst disclosed herein may include an alumina support. For the purposes of disclosure herein, the term "alumina support" includes any suitable type of alumina (Al2O3), such as alpha alumina, beta alumina, gamma alumina, eta alumina, theta alumina, amorphous alumina, etc., or a combination thereof.

[0050] On the one hand, hydrogenolysis catalyst disclosed herein can include zeolite carrier.For purposes disclosed herein, term " zeolite carrier " includes: zeolite structure, zeolite framework, aluminosilicate, aluminosilicate structure, aluminosilicate framework, zeolite-type material, zeolite-type structure, zeolite-type framework, molecular sieve, silicoaluminophosphate, silicoaluminophosphate structure, silicoaluminophosphate framework, aluminophosphate, aluminophosphate structure, aluminophosphate framework, or its combination.In addition, for purposes disclosed herein, zeolite structure, zeolite framework, aluminosilicate, aluminosilicate structure, aluminosilicate framework, zeolite-type material, zeolite-type structure, zeolite-type framework, molecular sieve, silicoaluminophosphate, silicoaluminophosphate structure, silicoaluminophosphate framework, aluminophosphate, aluminophosphate structure, aluminophosphate framework, or its combination is collectively referred to as " zeolite " in this article.

[0051] The zeolite carrier may include a zeolite, such as a small pore zeolite, a medium pore zeolite, a large pore zeolite, or a combination thereof. Zeolites are inorganic crystalline solids having a framework structure with channels and cavities of a characteristic pore geometry. Zeolites can be classified according to the opening of their pores. For example, a small pore zeolite has an 8-membered ring pore opening and can be characterized by: to The pore size (e.g., the diameter of the pore opening) of the medium-pore zeolite has a 10-membered ring pore opening, which can be characterized by to The pore size (eg, the diameter of the pore opening) of the large pore zeolite has a 12-membered ring pore opening, which can be characterized by to The pore size (e.g., the diameter of the pore opening).

[0052] In certain aspects, the zeolite support may comprise one or more aluminosilicate zeolites containing SiO4 and AlO4 tetrahedrons in its structure (e.g., framework structure). In other aspects, the zeolite catalyst may comprise: a zeolite-type material, such as a silicoaluminophosphate (SAPO) containing PO4, AlO4, and SiO4 tetrahedrons in a structure (e.g., framework structure); and / or an aluminophosphate (AlPO) containing PO4 and AlO4 tetrahedrons in a structure (e.g., framework structure). The SiO4, AlO4, and / or PO4 tetrahedrons share oxygen atoms, wherein the framework structure has well-defined channels and cavities (e.g., pores). These cavities may typically contain exchangeable cations, such as H + 、Na + and K + Without wishing to be limited by theory, in the zeolite framework structure or zeolite-type framework structure, Si or Al or P may be partially replaced by other trivalent or tetravalent elements (such as Ge, Ga, B, etc.). In addition, without wishing to be limited by theory, in the zeolite, Si or Al or P may also be partially replaced by one or more elements selected from the group consisting of titanium, nickel, copper, magnesium, tin, cobalt, iron, zinc, tungsten, vanadium, gallium, calcium, manganese, ruthenium, and rhenium.

[0053] Without wishing to be bound by theory, zeolites are generally characterized by a certain acidity due to the presence of Bronsted acid sites and / or Lewis acid sites. In zeolites, Bronsted acidic protons can be hydrogen atoms bonded to oxygen atoms, which connect to tetrahedrally coordinated aluminum that forms the structural framework of the zeolite. The Lewis acid centers in zeolites can contain tri-coordinated aluminum sites, which are electron-deficient sites that exhibit the ability to accept electrons during interactions with molecules. In some aspects, the acidity can be determined, for example, by using a Na-containing + and / or K +Zeolites suitable for use in the zeolite supports disclosed herein are treated with alkaline salt titration of cations (e.g., by impregnation, ion exchange, etc.) to reduce their acidity. As will be appreciated by those skilled in the art, and with the benefit of this disclosure, and without wishing to be limited by theory, acidic sites in the zeolite can promote the isomerization of n-butane to isobutane. In some aspects, the zeolite support can be characterized by low acidity and / or low aluminum content; for example, the zeolite support can be characterized by low Bronsted acidity. In some aspects, the zeolite support can be characterized by essentially no acidity (i.e., zero acidity).

[0054] In some aspects, the zeolite support can be characterized by a weight ratio of silica to alumina (SiO2 / Al2O3) of about 100 or greater, or about 150 or greater, or about 200 or greater, or about 250 or greater, or about 275 or greater, or about 300 or greater, or 100 to about 400, or about 200 to about 350, or about 250 to about 300, or about 275 to about 290, or about 280. In one aspect, the zeolite support (e.g., ZSM-5) can be characterized by a weight ratio of silica to alumina (SiO2 / Al2O3) of 280. As will be appreciated by those skilled in the art, and with the benefit of this disclosure, and without wishing to be bound by theory, the acidity of the support decreases as its weight ratio of silica to alumina (SiO2 / Al2O3) increases.

[0055] In one aspect, the zeolite carrier may comprise a zeolite, wherein the zeolite may be selected from the group consisting of ZSM-5, ZSM-11, Y zeolite, high silica Y, USY, EU-1, EU-2, β zeolite, L zeolite, ferrierite, CHA, SSZ-16, Nu-3, σ-1 zeolite, Silicalite-1 and combinations thereof.

[0056] In some aspects, the zeolite carrier can comprise, based on the total weight of the zeolite carrier: about 70 wt % to about 90 wt %, or about 75 wt % to about 85 wt %, or about 80 wt % of zeolite; and about 10 wt % to about 30 wt %, or about 15 wt % to about 25 wt %, or about 20 wt % of a binder (e.g., an alumina binder).

[0057] In one aspect, the zeolite support can be present in the hydrogenolysis bimetallic supported catalyst in an amount of about 90 wt% to about 99.9 wt%, or about 95 wt% to about 99.85 wt%, or about 99 wt% to about 99.8 wt%, based on the total weight of the hydrogenolysis bimetallic supported catalyst.

[0058] In one aspect, the bimetallic supported catalyst for hydrogenolysis disclosed herein can comprise a first metal, a second metal, and a zeolite support; wherein the first metal comprises Pt, the second metal comprises Ir, and the zeolite support comprises ZSM-5.

[0059] The bimetallic supported catalysts for hydrogenolysis disclosed herein may be prepared by any suitable method, such as described in more detail in U.S. Provisional Patent Application No. 62 / 733,309, filed on September 19, 2018, which is incorporated herein by reference in its entirety.

[0060] In one aspect, the bimetallic supported catalysts for hydrogenolysis disclosed herein can be characterized by a selectivity to ethane of about 60 mol% to about 90 mol%, or about 65 mol% to about 85 mol%, or about 70 mol% to about 80 mol%. In general, selectivity to one or more desired products refers to the amount of the desired carbon product formed divided by the total carbon products (desirable and undesirable) formed. For purposes of this disclosure, selectivity to a desired product is the selectivity % based on the number of moles converted to the desired product.

[0061] In one aspect, the bimetallic supported hydrogenolysis catalysts disclosed herein can be characterized by a selectivity to methane of less than about 20 mol%, or less than about 15 mol%, or less than about 12.5 mol%.

[0062] In one aspect, the bimetallic supported catalysts for hydrogenolysis disclosed herein can be characterized by a selectivity to propane of less than about 15 mol%, or less than about 12.5 mol%, or less than about 10 mol%.

[0063] In one aspect, hydrogenolysis reactor 100 can be characterized in that the isobutane conversion is less than the n-butane conversion. As will be appreciated by those skilled in the art, and with the benefit of this disclosure, the conversion of the reagents in hydrogenolysis depends on various reactor conditions, such as flow rates, temperature, etc.

[0064] In one aspect, hydrogenolysis reactor 100 can be characterized by an isobutane conversion of less than about 25%, or less than about 20%, or less than about 15%, or less than about 10%, or less than about 5%, or less than about 1%, or less than about 0.5%, or less than about 0.1%, or less than about 0.01%, or less than about 0.001%.

[0065] In one aspect, hydrogenolysis reactor 100 can be characterized by an n-butane conversion of about 75% or greater, or about 80% or greater, or about 85% or greater, or about 90% or greater, or about 95% or greater, or about 99% or greater. In some aspects, hydrogenolysis reactor 100 can be characterized by a 100% n-butane conversion. In some aspects, substantially all of the n-butane introduced into hydrogenolysis reactor 100 is converted; for example, hydrogenolysis product stream 20 is substantially free of n-butane.

[0066] In some aspects, hydrogenolysis reactor 100 can be characterized by an isobutane conversion of less than about 25%, and by an n-butane conversion of equal to or greater than about 90%.

[0067] In one aspect, the methods for producing MTBE disclosed herein may include feeding at least a portion of the hydrogenolysis product stream 20 to a first separation unit 200 (e.g., Figure 1 100) to produce a butane stream 30, a first hydrogen-containing gas stream 34, an optional methane stream 36, and a C2 to C3 gas stream 38; wherein the C2 to C3 gas stream 38 comprises ethane and propane, and wherein the butane stream 30 comprises isobutane and optionally normal butane. In the case where only a relatively small amount of methane is produced during hydrogenolysis (e.g., the amount of methane produced is relatively low), the methane can be separated together with the hydrogen, wherein the first hydrogen-containing gas stream 34 can comprise hydrogen and methane, and wherein the methane vapor alone cannot be recovered. In these aspects, the first hydrogen-containing gas stream 34 can be purged (e.g., before recycling the stream 34 to the reactor 100), for example, to avoid accumulation of methane in the reactor 100.

[0068] The first separation unit 200 may include any suitable separation unit configured to separate the hydrogenolysis product stream 20 into a butane stream 30, a first hydrogen-containing stream 34, an optional methane stream 36, and the C2 to C3 gas stream 38. For example, the first separation unit 200 may employ distillation, cryogenic distillation, extractive distillation, selective adsorption, selective absorption, etc., or a combination thereof. The first separation unit 200 may include a distillation tower, a cryogenic distillation tower, a tray-type and / or packed separation tower, a compressor, a heat exchanger, a cooling tower, a pressure swing adsorption (PSA) unit, etc.

[0069] Typically, hydrogen can be recovered using any suitable method (such as PSA, membrane separation, cryogenic separation, etc.). In some aspects, hydrogen (e.g., high purity hydrogen) can be recovered using a PSA method based on physical bonding of gas molecules to an adsorbent material, wherein the forces acting between the gas molecules and the adsorbent material depend on the gas composition, the type of adsorbent material, the partial pressure of the gas composition, and the operating temperature. The separation effect is based on the difference in the binding force to the adsorbent material. In contrast to molecules such as hydrocarbons, nitrogen, carbon monoxide, carbon dioxide, water vapor, and the like, highly volatile components with low polarity (such as hydrogen) are actually non-adsorbable, and therefore high purity hydrogen can be recovered.

[0070] The individual hydrocarbons or hydrocarbon fractions may typically be recovered by a fractionation process which may employ a variety of columns, such as a cryogenic distillation tower configuration including a demethanizer, a deethanizer, a depropanizer, and the like.

[0071] In some aspects, butane stream 30 can be fed to dehydrogenation reactor 300, for example, as Figure 1 shown and will be described in more detail below.

[0072] In the case where butane stream 30 comprises n-butane, the n-butane may be separated from butane stream 30, for example, by cryogenic distillation, to produce n-butane stream 32. n-butane stream 32 may be recycled to hydrogenolysis reactor 100.

[0073] In some aspects, the first separation unit 200 (eg Figure 2 ) can be configured to separate the hydrogenolysis product stream 20 into a first isobutane stream 31, an n-butane stream 32, a first hydrogen-containing stream 34, an optional methane stream 36, and the C2 to C3 gas stream 38. In these aspects, the first isobutane stream 31 can be fed to a dehydrogenation reactor 300, for example, as Figure 2 As shown and described in more detail below; and the n-butane stream 32 can be optionally recycled to the hydrogenolysis reactor 100.

[0074] In one aspect, at least a portion 34a of first hydrogen-containing gas stream 34 may be recycled to hydrogenolysis reactor 100 .

[0075] In one aspect, the C2 to C3 gas stream 38 can be characterized by a weight ratio of ethane to propane of equal to or greater than about 2:1, or equal to or greater than about 3:1, or equal to or greater than about 4:1, or equal to or greater than about 5:1, or equal to or greater than about 6:1, or equal to or greater than about 7:1.

[0076] In some aspects, at least a portion of the C2 to C3 gas stream 38 can be fed to a gas steam cracker to produce a steam cracker product stream, wherein the steam cracker product stream comprises olefins, wherein the amount of olefins in the steam cracker product stream is greater than the amount of olefins in the C2 to C3 gas stream 38, and wherein the olefins include ethylene and propylene. The olefins may comprise ethylene and propylene in a weight ratio of ethylene to propylene equal to or greater than about 4:1, or equal to or greater than about 5:1, or equal to or greater than about 6:1, or equal to or greater than about 7:1. Steam cracking of ethane and / or propane is described in more detail in U.S. Provisional Patent Application No. 62 / 733,284, filed on September 19, 2018, which is incorporated herein by reference in its entirety.

[0077] In one aspect, the methods for producing MTBE disclosed herein may include feeding at least a portion of a butane stream 30 to a dehydrogenation reactor 300 (e.g., Figure 1 ) to produce a dehydrogenated product stream 40, wherein the dehydrogenation reactor 300 comprises a dehydrogenation catalyst, and wherein the dehydrogenated product stream 40 comprises hydrogen, isobutane and isobutene. In the case where the butane stream 30 comprises normal butane, the dehydrogenated product stream 40 may further comprise 1-butene, 2-butene, butadiene or a combination thereof.

[0078] In the case where n-butane is recovered from the butane stream (e.g., in the first separation unit 200), the methods for producing MTBE disclosed herein may include feeding at least a portion of the first isobutane stream 31 to a dehydrogenation reactor 300 (e.g., Figure 2 ) to produce a dehydrogenation product stream 40; wherein the dehydrogenation product stream 40 comprises hydrogen, isobutane and isobutene.

[0079] In one aspect, the dehydrogenation of the butane stream 30 and / or the first isobutane stream 31 can be performed using any suitable method. For example, the dehydrogenation of the butane stream 30 and / or the first isobutane stream 31 can be performed by The dehydrogenation process is performed, although any other suitable dehydrogenation process may be used to dehydrogenate butane stream 30 and / or first isobutane stream 31. The dehydrogenation method is a method of Lummus Technology, which is used for the dehydrogenation of isobutane, normal butane, propane, etc. to produce isobutene, normal butene, propylene, etc., respectively. The dehydrogenation process uses a fixed bed reactor, and its catalyst and operating conditions are selected to optimize conversion and selectivity. For example, the overall selectivity of isobutylene dehydrogenation in the dehydrogenation process to isobutylene can be greater than 90%.

[0080] In one aspect, the dehydrogenation reactor 300 can include any suitable dehydrogenation reactor, such as a continuous flow fixed bed reactor.

[0081] The dehydrogenation reactor 300 may contain any suitable dehydrogenation catalyst, such as a chromium oxide-aluminum oxide (Cr2O3 / Al2O3) catalyst.

[0082] In one aspect, the method for producing MTBE disclosed herein may include feeding at least a portion of the dehydrogenation product stream 40 and methanol 46 to the etherification unit 400 (e.g., Figure 1 ) to produce an unreacted methanol stream 52, an unreacted isobutylene stream 53 and an MTBE stream 50.

[0083] In the case where the dehydrogenated product stream 40 contains hydrocarbons other than isobutylene, the unreacted isobutylene stream 53 may contain at least a portion of such hydrocarbons, such as isobutane, n-butane, 1-butene, 2-butene, butadiene, or a combination thereof. In some aspects, at least a portion 53a of the unreacted isobutylene stream 53 may be recycled to the etherification unit 400. In one aspect, isobutylene may be separated from the unreacted isobutylene stream 53, for example, by cryogenic distillation, wherein the separated isobutylene may be recycled to the etherification unit 400.

[0084] In the event that the dehydrogenated product stream 40 comprises hydrocarbons other than isobutylene, the dehydrogenated product stream 40 may be subjected to a separation step to recover the isobutylene, wherein at least a portion of the recovered isobutylene (e.g., isobutylene stream 45) may be fed to the etherification unit 400, e.g., as Figure 2 In these aspects, unreacted isobutylene stream 51 can be recovered from the etherification unit 400, wherein at least a portion 51a of the unreacted isobutylene stream 51 can be recycled to the etherification unit 400.

[0085] In one aspect, at least a portion 52a of the unreacted methanol stream 52 may be recycled to the etherification unit 400 .

[0086] In one aspect, the etherification of the dehydrogenated product stream 40 and / or the isobutylene stream 45 with methanol (MeOH) can be performed using any suitable method. For example, the etherification of the dehydrogenated product stream 40 and / or the isobutylene stream 45 with MeOH can be performed by Lummus Technology's The etherification of dehydrogenated product stream 40 and / or isobutylene stream 45 with methanol may be carried out using a catalytic distillation technique, although any other suitable etherification process may be used. The catalytic distillation technology process has a two-step reactor design consisting of a boiling point fixed bed reactor followed by conversion in a catalytic distillation column. The catalytic distillation technology method uses an acidic ion exchange resin catalyst in both a fixed bed reactor and a catalytic distillation tower. The boiling point reactor is designed so that the liquid reaches its boiling point by absorbing the heat of reaction, after which a limited amount of vaporization occurs, thereby maintaining precise temperature control. The maximum temperature is adjusted by controlling the total pressure of the system. The catalytic distillation tower combines reaction and fractionation in a single unit operation, thereby achieving a high conversion rate of isobutylene (exceeding the fixed bed equilibrium limit). Without wishing to be limited by theory, by using distillation to separate the product from the reactant, the apparent equilibrium limit is exceeded and a higher isobutylene conversion rate can be achieved. In addition, without wishing to be limited by theory, catalytic distillation also takes advantage of the improved kinetics by increasing the temperature without compromising the equilibrium conversion.

[0087] In one aspect, the etherification unit 400 can include any suitable etherification reactor configuration. For example, the etherification unit 400 can include a boiling point fixed bed reactor and a catalytic distillation reactor. The catalytic distillation reactor can be downstream of the boiling point fixed bed reactor, wherein the MTBE stream 50 can be recovered from the catalytic distillation reactor as a bottom stream.

[0088] In some aspects, the boiling point fixed bed reactor can contain a first acidic ion exchange resin catalyst and the catalytic distillation reactor can contain a second acidic ion exchange resin catalyst, wherein the first acidic ion exchange resin catalyst and the second acidic ion exchange resin catalyst can be the same or different.

[0089] In one aspect, the methods for producing MTBE disclosed herein may include optionally separating the second separation unit 350 (e.g. Figure 2 At least a portion of the dehydrogenated product stream 40 in the second separation unit 350 is separated into a second hydrogen-containing stream 44, a second isobutane stream 41 and an isobutylene stream 45. In some aspects, since the separation efficiency in the second separation unit 350 is less than 100%, the second hydrogen-containing gas stream 44 may also contain a relatively low amount of hydrocarbons (e.g., isobutane, isobutylene, etc.).

[0090] The second separation unit 350 may include any suitable separation unit configured to separate the dehydrogenated product stream 40 into a second hydrogen-containing gas stream 44, a second isobutane stream 41, and an isobutene stream 45. For example, the second separation unit 350 may employ distillation, cryogenic distillation, extractive distillation, selective adsorption, selective absorption, etc., or a combination thereof. The second separation unit 350 may include a distillation tower, a cryogenic distillation tower, a tray-type and / or packed separation tower, a compressor, a heat exchanger, a cooling tower, a pressure swing adsorption (PSA) unit, etc.

[0091] In one aspect, the methods for producing MTBE disclosed herein may include feeding at least a portion of the isobutylene stream 45 to an etherification unit 400 .

[0092] In one aspect, at least a portion 44a of the second hydrogen-containing gas stream 44 may be recycled to the hydrogenolysis reactor 100 .

[0093] In one aspect, at least a portion 41a of the second isobutane stream 41 may be recycled to the dehydrogenation reactor 300 .

[0094] In one aspect, the methods disclosed herein for producing MTBE (e.g., Figure 2) may include: (a) introducing a butane feed stream 10 and hydrogen 15 into a hydrogenolysis reactor 100 to produce a hydrogenolysis product stream 20, wherein the hydrogenolysis reactor 100 comprises a hydrogenolysis bimetallic supported catalyst, wherein the hydrogenolysis bimetallic supported catalyst comprises Pt and Ir supported on ZSM-5, wherein the hydrogenolysis reactor 100 is characterized by a temperature of less than about 330° C., wherein the hydrogenolysis reactor 100 is characterized by an isobutane conversion of less than about 25%, wherein the butane feed stream 10 comprises normal butane and isobutane, wherein the butane feed stream 10 is characterized by a normal butane ratio of equal to or greater than about 1:1 (a) separating at least a portion of the hydrogenolysis product stream 22 in a first separation unit 200 into a first hydrogen-containing gas stream 34, an optional methane stream 36, a C2 to C3 gas stream 38, a first isobutane stream 31, and an optional n-butane stream 32, wherein the C2 to C3 gas stream 38 comprises ethane and propane; (c) feeding at least a portion of the isobutane stream 31 to a dehydrogenation reactor 300 to produce a dehydrogenated product stream 40, wherein the dehydrogenation reactor 300 comprises a dehydrogenation catalyst (e.g., a chromium oxide-aluminum oxide catalyst), and wherein the dehydrogenation product stream 40 comprises hydrogen, isobutane and isobutene; (d) separating at least a portion of the dehydrogenation product stream 40 into a second hydrogen-containing gas stream 44, a second isobutane stream 41 and an isobutene stream 45 in a second separation unit 350; (e) feeding at least a portion of the isobutene stream 45 and methanol 46 to an etherification unit 400 to produce an unreacted methanol stream 52, an unreacted isobutene stream 51 and an MTBE stream 50; (f) optionally recycling at least a portion 52a of the unreacted methanol stream 52 and / or at least a portion 51a of the unreacted isobutene stream 51 to the etherification unit; (g) optionally recycling the second isobutane stream 41 to the etherification unit; (h) optionally recycling at least a portion 34a of the first hydrogen-containing gas stream 34 and / or at least a portion 44a of the second hydrogen-containing gas stream 44 to the hydrogenolysis reactor 100; and (i) optionally feeding at least a portion of the C2 to C3 gas stream 38 to a steam cracking furnace to produce a steam cracker product stream, wherein the steam cracker product stream comprises olefins, wherein the amount of olefins in the steam cracker product stream is greater than the amount of olefins in the C2 to C3 gas stream 38, and wherein the olefins include ethylene and propylene in a weight ratio of ethylene to propylene equal to or greater than about 5:1.

[0095] In one aspect, the method for producing MTBE disclosed herein can advantageously exhibit improvements in one or more process characteristics when compared to other similar methods lacking the step of introducing a butane feed stream and hydrogen into a hydrogenolysis reactor. Conventionally, a plant-grade butane stream can be isomerized to convert normal butane to isobutane; however, this conversion is incomplete (because it is limited by equilibrium). The method for producing MTBE disclosed herein can advantageously increase the conversion of normal butane in the hydrogenolysis reactor, thereby reducing the load on the separation unit and the volume of the recycle stream.

[0096] On the one hand, the method for producing MTBE disclosed herein can advantageously provide a reactive separation of a plant-level butane stream, wherein n-butane can be converted in a hydrogenolysis reactor, and wherein isobutane can be recovered and dehydrogenated to isobutene, thereby providing a more efficient method for separating isobutane from n-butane, wherein the product of the n-butane conversion can be further steam cracked to produce ethylene. Compared to the amount of ethane produced from a similar feed stream undergoing hydrocracking, the hydrogenolysis disclosed herein can increase the amount of ethane. Other advantages of the method for producing MTBE as disclosed herein are obvious to those skilled in the art.

[0097] Example

[0098] Having generally described the subject matter of the invention, the following examples are given as specific embodiments of the present disclosure and demonstrate its practice and advantages. It should be understood that these examples are given by way of example and are not intended to limit the description of the appended claims in any way.

[0099] Example 1

[0100] The selective hydrogenolysis of butane was studied in the presence of a variety of monometallic catalysts (e.g., hydrogenolysis monometallic supported catalysts) and bimetallic catalysts (e.g., hydrogenolysis bimetallic supported catalysts). The data provided below are experimental data related to a bimetallic catalyst (Ir, Pt / ZSM-5) comprising 0.3 wt% Ir and 0.3 wt% Pt supported on ZSM-5, wherein the ZSM-5 support is characterized by a weight ratio of silica to alumina (SAR or SiO2 / Al2O3) of 280. The bimetallic catalyst (Ir, Pt / ZSM-5) was used in experiments conducted under two different conditions. The results of these experiments indicate that a reactive separation can be achieved between n-butane and isobutane when the catalyst (e.g., hydrogenolysis catalyst) is subjected to a reaction (e.g., hydrogenolysis) under a very specific set of conditions. The data are shown in Table 1.

[0101] Table 1: Examples of selective hydrogenolysis reactions coupled with MTBE production

[0102]

[0103] In addition, a comparative experiment (Comparative Example B) was performed and the resulting data are also shown in Table 1. In the comparative experiment at a temperature of 350° C., it can be seen that both n-butane and isobutane are completely converted. Another comparative experiment (Comparative Example C) shows that at high WHSV and H2 / C4 molar ratio, the consumption of n-butane is insufficient to allow reactive separation from isobutane.

[0104] However, it was unexpectedly found that by adjusting the temperature to 300 °C, the WHSV was 4 h -1 , the H2 / C4 molar ratio is 2.5, and the conversion of n-butane is still close to complete (99-100%); however, the conversion of isobutane is significantly reduced (10-15%). Due to this phenomenon from the selective hydrogenolysis / reactive separation experimental run, the product stream consists of gases (i.e., methane, ethane, propane, and isobutane). Isobutane is easily separated from this mixture. Since n-butane is not present, the conventional isomerization and separation unit for n / -C4 is not required. Therefore, isobutane can be fed directly to a conventional dehydrogenation unit to form isobutylene, which is then reacted with methanol to form the product MTBE.

[0105] Another comparative example (Comparative Example A) is a case where the selective hydrogenolysis reaction is not performed, wherein in Comparative Example A, an isomerization unit must be used to separate n-butane from isobutane to convert a portion of n-butane into isobutane, and then a boiling point separation column is used to separate n-butane from isobutane. The n-butane will be recycled to disappear in the isomerization unit, and the isobutane will enter the dehydrogenation unit and produce MTBE. By using the selective hydrogenolysis / reaction separation experiment performed in Table 1, the traditional isomerization and separation steps, which are very energy-consuming, can be avoided.

[0106] For the purpose of submitting any U.S. national phase application from this application, all publications and patents mentioned in this disclosure are incorporated herein by reference in their entirety for the purpose of describing and disclosing the constructions and methods described in those publications, which can be used in combination with the methods of the present disclosure. Any publications and patents discussed in this disclosure are provided only because they were disclosed prior to the filing date of this application. Nothing herein should be construed as admitting that the inventor has no right to preempt such disclosures by virtue of prior inventions.

[0107] The Abstract of this application is provided in any application filed with the United States Patent and Trademark Office to satisfy the requirements of 37 CFR § 1.72 and the purpose stated in 37 CFR § 1.72(b) "to enable the United States Patent and Trademark Office and the public to rapidly ascertain the nature and gist of the technical disclosure from a cursory inspection." Therefore, the Abstract of this application is not intended to be used to construe the scope of the claims or to limit the scope of the subject matter disclosed herein. Furthermore, any headings that may be adopted herein are not intended to be used to construe the scope of the claims or to limit the scope of the subject matter disclosed herein. Any use of the past tense to describe an example otherwise presented as constructive or prophetic is not intended to reflect that the constructive or prophetic example has actually been performed.

[0108] The present invention is further illustrated by the following examples, which are not to be construed in any way as limiting the scope of the invention. On the contrary, it should be clearly understood that various other aspects, embodiments, modifications and equivalents thereof may be resorted to, which may be suggested to those of ordinary skill in the art without departing from the spirit of the invention or the scope of the appended claims after reading the description herein.

[0109] Other public content

[0110] In a first aspect, it is a method comprising: (a) introducing a butane feed stream and hydrogen into a hydrogenolysis reactor to produce a hydrogenolysis product stream, wherein the hydrogenolysis reactor comprises a hydrogenolysis catalyst, wherein the butane feed stream comprises normal butane and isobutane, and wherein the hydrogenolysis product stream comprises hydrogen, methane, ethane, propane, isobutane, and optionally normal butane; (b) separating at least a portion of the hydrogenolysis product stream into a first hydrogen-containing gas stream, an optional methane stream, a C2 to C3 gas stream, and a butane stream in a first separation unit, wherein the C2 to C3 gas stream comprises ethane and propane, and wherein the butane stream comprises isobutane and optionally normal butane; and (c) feeding at least a portion of the butane stream to a dehydrogenation reactor to produce a dehydrogenation product stream, wherein the dehydrogenation reactor comprises a dehydrogenation catalyst, and wherein the dehydrogenation product stream comprises hydrogen, isobutane, and isobutylene.

[0111] A second aspect is a method according to the first aspect, wherein the n-butane is present in the butane feed stream in an amount equal to or greater than about 50 mol%.

[0112] The third aspect is a method according to the first aspect and the first aspect, further comprising: (i) feeding at least a portion of the dehydrogenation product stream and methanol to an etherification unit to produce an unreacted methanol stream, an unreacted isobutylene stream and a methyl tert-butyl ether (MTBE) stream; and (ii) optionally recycling at least a portion of the unreacted methanol stream and / or at least a portion of the isobutylene stream to the etherification unit.

[0113] A fourth aspect is a method according to any one of the first to third aspects, wherein the hydrogenolysis reactor is characterized by: a temperature of about 200°C to about 330°C; a pressure of about 0 psig to about 300 psig; and a temperature of about 0.1 h. -1 About 15h -1 and a molar ratio of hydrogen to C4 hydrocarbons of from about 1:1 to about 10:1.

[0114] A fifth aspect is a method according to any one of aspects 1 to 4, wherein the hydrogenolysis catalyst comprises a hydrogenolysis monometallic supported catalyst and / or a hydrogenolysis bimetallic supported catalyst; wherein the hydrogenolysis monometallic supported catalyst comprises a zeolite-supported monometallic catalyst and / or an alumina-supported monometallic catalyst; wherein the hydrogenolysis bimetallic supported catalyst comprises a zeolite-supported bimetallic catalyst and / or an alumina-supported bimetallic catalyst; wherein the hydrogenolysis bimetallic supported catalyst comprises a first metal and a second metal, wherein the first metal and the second metal are different; wherein the hydrogenolysis monometallic supported catalyst comprises a third metal; wherein the third metal is different from the first metal and / or the second The metals are the same or different, wherein the first metal, the second metal and the third metal can each be independently selected from the group consisting of iridium (Ir), platinum (Pt), rhodium (Rh), ruthenium (Ru), palladium (Pd), molybdenum (Mo), tungsten (W), nickel (Ni) and cobalt (Co); wherein the carrier comprises alumina and / or zeolite; wherein the zeolite is selected from the group consisting of ZSM-5, ZSM-11, Y, high silicon Y, USY, EU-1, EU-2, β, L, ferrierite, CHA, SSZ-16, Nu-3, σ-1, silica zeolite and combinations thereof; and wherein the carrier optionally comprises a binder, the binder comprising alumina, titania, silica or combinations thereof.

[0115] A sixth aspect is a method according to any one of the first to fifth aspects, wherein the hydrogenolysis catalyst comprises Pt and Ir supported on ZSM-5.

[0116] A seventh aspect is a method according to any one of aspects 1 to 6, further comprising: (i) separating at least a portion of the dehydrogenation product stream into a second hydrogen-containing gas stream, an isobutane stream and an isobutylene stream in a second separation unit; and (ii) feeding at least a portion of the isobutylene stream to the etherification unit.

[0117] An eighth aspect, which is a method according to any one of aspects 1 to 7, further comprising: recycling at least a portion of the first hydrogen-containing gas stream and / or at least a portion of the second hydrogen-containing gas stream to the hydrogenolysis reactor.

[0118] A ninth aspect, which is a method according to any one of aspects 1 to 8, further comprising: recycling at least a portion of the isobutane stream to the dehydrogenation reactor.

[0119] A tenth aspect is a method according to any one of aspects 1 to 9, wherein the step (b) of separating at least a portion of the hydrogenolysis product stream in the first separation unit also includes separating at least a portion of n-butane from the hydrogenolysis product stream.

[0120] An eleventh aspect, which is a method according to any one of the first to tenth aspects, further comprising: recycling at least a portion of the separated n-butane to the hydrogenolysis reactor.

[0121] A twelfth aspect, which is the method of any one of aspects 1 to eleven, wherein the hydrogenolysis reactor is characterized by an isobutane conversion rate of less than about 25%.

[0122] A thirteenth aspect, which is the method of any one of aspects one to twelve, wherein the hydrogenolysis reactor is characterized by an n-butane conversion rate equal to or greater than about 90%.

[0123] A fourteenth aspect, which is a method described in any one of aspects one to thirteen, further comprising: feeding at least a portion of the C2 to C3 gas stream to a gas steam cracking furnace to produce a steam cracker product stream, wherein the steam cracker product stream contains olefins, wherein the amount of olefins in the steam cracker product stream is greater than the amount of olefins in the C2 to C3 gas stream, and wherein the olefins include ethylene and propylene.

[0124] A fifteenth aspect, which is a method as described in any one of aspects one to fourteen, wherein the weight ratio of ethane to propane in the C2 to C3 gas stream is equal to or greater than about 2:1.

[0125] In a sixteenth aspect, a method for producing methyl tert-butyl ether (MTBE) comprises: (a) introducing a butane feed stream and hydrogen into a hydrogenolysis reactor to produce a hydrogenolysis product stream, wherein the hydrogenolysis reactor comprises a hydrogenolysis bimetallic supported catalyst, wherein the hydrogenolysis bimetallic supported catalyst comprises Pt and Ir supported on ZSM-5, wherein the hydrogenolysis reactor is characterized by a temperature of less than about 330° C., wherein the hydrogenolysis reactor is characterized by an isobutane conversion rate of less than about 25%, wherein the butane feed stream comprises normal butane and isobutane, wherein the butane feed stream is characterized by a molar ratio of normal butane to isobutane equal to or greater than about 1:1, and wherein the hydrogenolysis product stream comprises hydrogen, methane, ethane, propane and (b) separating at least a portion of the hydrogenolysis product stream into a first hydrogen-containing gas stream, an optional methane stream, a C2 to C3 gas stream and a first isobutane stream in a first separation unit, wherein the C2 to C3 gas stream comprises ethane and propane; (c) feeding at least a portion of the isobutane stream to a dehydrogenation reactor to produce a dehydrogenated product stream, wherein the dehydrogenation reactor comprises a dehydrogenation catalyst, and wherein the dehydrogenated product stream comprises hydrogen, isobutane and isobutylene; (d) separating at least a portion of the dehydrogenated product stream into a second hydrogen-containing gas stream, a second isobutane stream and an isobutylene stream in a second separation unit; and (e) feeding at least a portion of the isobutylene stream and methanol to an etherification unit to produce an unreacted methanol stream, an unreacted isobutylene stream and an MTBE stream.

[0126] A seventeenth aspect, which is a method according to aspect sixteen, further comprising: feeding at least a portion of the C2 to C3 gas stream to a gas steam cracking furnace to produce a steam cracker product stream, wherein the steam cracker product stream contains olefins, wherein the amount of olefins in the steam cracker product stream is greater than the amount of olefins in the C2 to C3 gas stream, and wherein the olefins include ethylene and propylene in a weight ratio of ethylene to propylene equal to or greater than about 5:1.

[0127] An eighteenth aspect, which is a method according to any one of aspects sixteen and seventeen, further comprising: recycling at least a portion of the first hydrogen-containing gas stream and / or at least a portion of the second hydrogen-containing gas stream to the hydrogenolysis reactor.

[0128] A nineteenth aspect, which is a method according to any one of aspects sixteen to eighteen, further comprising: recycling at least a portion of the second isobutane stream to the dehydrogenation reactor.

[0129] A twentieth aspect, which is the method of any one of aspects 16 to 19, further comprising: recycling at least a portion of the unreacted methanol stream and / or at least a portion of the unreacted isobutylene stream to the etherification unit.

[0130] Although the embodiments of the present disclosure have been shown and described, they can be modified without departing from the spirit and teachings of the present invention. The embodiments and examples described herein are merely exemplary and are not intended to be limiting. Many variations and modifications of the present invention disclosed herein are possible and are within the scope of the present invention.

[0131] Accordingly, the scope of protection is not limited by the above statements, but only by the attached claims, which include all equivalent forms of the subject matter of the claims. Each claim is incorporated into the specification as an embodiment of the present invention. Therefore, the claims are further descriptions and are supplementary to the specific embodiments of the present invention. The disclosures of all patents, patent applications and publications cited herein are incorporated herein by reference.

Claims

1. A selective hydrogenolysis method comprising: (a) introducing a butane feed stream and hydrogen into a hydrogenolysis reactor to produce a hydrogenolysis product stream, wherein the hydrogenolysis reactor comprises a hydrogenolysis catalyst comprising Pt and Ir supported on ZSM-5, wherein the hydrogenolysis reactor is characterized by a temperature of less than 330° C., wherein the butane feed stream comprises n-butane and isobutane, and wherein the hydrogenolysis product stream comprises hydrogen, methane, ethane, propane, isobutane, and optionally n-butane; (b) separating at least a portion of the hydrogenolysis product stream into a first hydrogen-containing gas stream, an optional methane stream, a C2 to C3 gas stream, and a butane stream in a first separation unit, wherein the C2 to C3 gas stream comprises ethane and propane, and wherein the butane stream comprises isobutane and optionally n-butane; and (c) feeding at least a portion of the butane stream to a dehydrogenation reactor to produce a dehydrogenated product stream, wherein the dehydrogenation reactor comprises a dehydrogenation catalyst, and wherein the dehydrogenated product stream comprises hydrogen, isobutane, and isobutylene.

2. The method according to claim 1, wherein: The n-butane is present in the butane feed stream in an amount equal to or greater than 50 mol%.

3. The method according to claim 1, further comprising: (i) feeding at least a portion of the dehydrogenation product stream and methanol to an etherification unit to produce an unreacted methanol stream, an unreacted isobutylene stream and a methyl tert-butyl ether (MTBE) stream; and (ii) optionally recycling at least a portion of the unreacted methanol stream and / or at least a portion of the isobutylene stream to the etherification unit.

4. The method according to claim 1, wherein: The hydrogenolysis reactor is characterized by: a temperature of 200°C to 330°C, a pressure of 0 psig to 300 psig; 0.1 h -1 Until 15h -1 and a molar ratio of hydrogen to C4 hydrocarbons of from 1:1 to 10:

1.

5. The method according to claim 1, wherein: The hydrogenolysis catalyst comprises a hydrogenolysis monometallic supported catalyst and / or a hydrogenolysis bimetallic supported catalyst; wherein the hydrogenolysis monometallic supported catalyst comprises a zeolite-supported monometallic catalyst and / or an alumina-supported monometallic catalyst; wherein the hydrogenolysis bimetallic supported catalyst comprises a zeolite-supported bimetallic catalyst and / or an alumina-supported bimetallic catalyst; wherein the hydrogenolysis bimetallic supported catalyst comprises a first metal and a second metal, wherein the first metal and the second metal are different; wherein the hydrogenolysis monometallic supported catalyst comprises a third metal; wherein the third metal is the same as or different from the first metal and / or the second metal; wherein the The first metal, the second metal and the third metal can each be independently selected from the group consisting of iridium (Ir), platinum (Pt), rhodium (Rh), ruthenium (Ru), palladium (Pd), molybdenum (Mo), tungsten (W), nickel (Ni) and cobalt (Co); wherein the carrier comprises alumina and / or zeolite; wherein the zeolite is selected from the group consisting of ZSM-5, ZSM-11, Y, high silicon Y, USY, EU-1, EU-2, β, L, ferrierite, CHA, SSZ-16, Nu-3, σ-1, silica zeolite and combinations thereof; and wherein the carrier optionally comprises a binder, the binder comprising alumina, titania, silica or combinations thereof.

6. The method according to claim 1, wherein: The total amount of Pt and Ir present in the hydrogenolysis catalyst is from 0.1 wt % to 1 wt % based on the total weight of the hydrogenolysis catalyst.

7. The method according to claim 1, further comprising: (i) separating at least a portion of the dehydrogenated product stream into a second hydrogen-containing gas stream, an isobutane stream, and an isobutene stream in a second separation unit; and (ii) feeding at least a portion of the isobutylene stream to an etherification unit.

8. The method according to claim 7, further comprising: At least a portion of the first hydrogen-containing gas stream and / or at least a portion of the second hydrogen-containing gas stream is recycled to the hydrogenolysis reactor.

9. The method according to claim 1, further comprising: At least a portion of the isobutane stream is recycled to the dehydrogenation reactor.

10. The method according to claim 1, wherein: The step (b) of separating at least a portion of the hydrogenolysis product stream in a first separation unit further comprises separating at least a portion of n-butane from the hydrogenolysis product stream.

11. The method according to claim 10, further comprising: At least a portion of the separated n-butane is recycled to the hydrogenolysis reactor.

12. The method according to claim 1, wherein: The hydrogenolysis reactor is characterized by an isobutane conversion of less than 25%.

13. The method according to claim 1, wherein: The hydrogenolysis reactor is characterized by an n-butane conversion equal to or greater than 90%.

14. The method according to claim 1, further comprising: At least a portion of the C2 to C3 gas stream is fed to a gas steam cracking furnace to produce a steam cracker product stream, wherein the steam cracker product stream comprises olefins, wherein the amount of olefins in the steam cracker product stream is greater than the amount of olefins in the C2 to C3 gas stream, and wherein the olefins include ethylene and propylene.

15. The method according to claim 1, wherein: The weight ratio of ethane to propane in the C2 to C3 gas stream is equal to or greater than 2:

1.

16. A method for producing methyl tert-butyl ether (MTBE), comprising: (a) introducing a butane feed stream and hydrogen into a hydrogenolysis reactor to produce a hydrogenolysis product stream, wherein the hydrogenolysis reactor comprises a hydrogenolysis bimetallic supported catalyst, wherein the hydrogenolysis bimetallic supported catalyst comprises Pt and Ir supported on ZSM-5, wherein the hydrogenolysis reactor is characterized by a temperature of less than 330° C., wherein the hydrogenolysis reactor is characterized by an isobutane conversion of less than 25%, wherein the butane feed stream comprises n-butane and isobutane, wherein the butane feed stream is characterized by a molar ratio of n-butane to isobutane equal to or greater than 1:1, and wherein the hydrogenolysis product stream comprises hydrogen, methane, ethane, propane, and isobutane; (b) separating at least a portion of the hydrogenolysis product stream into a first hydrogen-containing gas stream, an optional methane stream, a C2 to C3 gas stream, and a first isobutane stream in a first separation unit, wherein the C2 to C3 gas stream comprises ethane and propane; (c) feeding at least a portion of the first isobutane stream to a dehydrogenation reactor to produce a dehydrogenated product stream, wherein the dehydrogenation reactor comprises a dehydrogenation catalyst, and wherein the dehydrogenated product stream comprises hydrogen, isobutane, and isobutylene; (d) separating at least a portion of the dehydrogenated product stream into a second hydrogen-containing gas stream, a second isobutane stream, and an isobutene stream in a second separation unit; (e) feeding at least a portion of the isobutylene stream and methanol to an etherification unit to produce an unreacted methanol stream, an unreacted isobutylene stream, and an MTBE stream; and (f) recycling at least a portion of the unreacted methanol stream and at least a portion of the unreacted isobutylene stream to the etherification unit, Wherein, based on the total weight of the hydrogenolysis bimetallic supported catalyst, the total amount of Pt and Ir present in the hydrogenolysis bimetallic supported catalyst is 0.1 wt % to 1 wt %.

17. The method according to claim 16, further comprising: At least a portion of the C2 to C3 gas stream is fed to a gas steam cracker to produce a steam cracker product stream, wherein the steam cracker product stream comprises olefins, wherein the amount of olefins in the steam cracker product stream is greater than the amount of olefins in the C2 to C3 gas stream, and wherein the olefins include ethylene and propylene in a weight ratio of ethylene to propylene equal to or greater than 5:

1.

18. The method according to claim 16, further comprising: At least a portion of the first hydrogen-containing gas stream and / or at least a portion of the second hydrogen-containing gas stream is recycled to the hydrogenolysis reactor.

19. The method according to claim 16, further comprising: At least a portion of the second isobutane stream is recycled to the dehydrogenation reactor.

20. The method according to claim 16, wherein: The hydrogenolysis reactor is characterized by a temperature of 280°C to 310°C.

21. The method according to claim 16, wherein: The ZSM-5 is characterized by a weight ratio of silicon dioxide to aluminum oxide, SiO2 / Al2O3, equal to or greater than 250.

22. The method according to claim 16, wherein: The weight ratio of ethane to propane in the C2 to C3 gas stream is equal to or greater than 4:

1.

23. The method according to claim 16, wherein: The hydrogenolysis reactor is characterized by an isobutane conversion of less than 15%, and wherein the hydrogenolysis reactor is characterized by an n-butane conversion of equal to or greater than 95%.

Images