Method for producing a fuel additive A method for producing a fuel additive

Abstract

A method of producing a fuel additive, comprising: passing a feed stream comprising C4 hydrocarbons through a methyl tertiary butyl ether unit to produce a first process stream; passing the first process stream through a selective butadiene hydrogenation unit that converts greater than or equal to 90 wt% of butadiene to 1-butene and 2-butene, preferably greater than or equal to 93%, preferably greater than or equal to 94%, more preferably greater than or equal to 95%, to produce a second process stream; passing the second process stream through a hydration unit to produce a third process stream and a fuel additive; passing the third process stream through a total hydrogenation unit to produce a hydrogenated stream; and passing the hydrogenated stream through a cracker unit.

Description

[0001] This application is a divisional application of the invention patent application filed on April 18, 2019, with application number 201980028131.1 and invention title "Method for producing fuel additives". Technical Field

[0002] This invention relates to a method for producing fuel additives. Background Technology

[0003] Commercial gasoline is a fuel for internal combustion engines and is a refined petroleum product, typically a mixture of hydrocarbons (base oil), additives, and blending agents. Additives and blending agents are added to the base oil to enhance the performance and stability of gasoline, such as octane boosters.

[0004] When used in high-compression internal combustion engines, gasoline has a tendency to "knock." Knock occurs when the combustion of the air / fuel mixture in the cylinder begins before proper ignition, because one or more air / fuel mixture cells ignite prematurely outside the envelope of the normal combustion front. Antiknock agents, also known as octane boosters, reduce engine knocking and increase the octane rating of gasoline.

[0005] Hydrocarbon cracking is an important conversion process used in refineries. For example, fluid catalytic cracking (FCC) is widely used to convert high-boiling, high-molecular-weight hydrocarbon fractions from crude oil into more valuable gasoline, olefin gases, and other products. Thermal cracking of naphtha and gas oil is also widely used in the petrochemical industry to produce various olefins and aromatics. For instance, hydrocarbon feedstocks are mixed with steam and subjected to high temperatures (e.g., 700–900°C) in a steam cracker, where the feedstock is broken down into various fractions. The effluent from the steam cracker can contain a gaseous mixture of hydrocarbons, such as saturated and unsaturated olefins and aromatics (C1–C35). The effluent can then be separated into individual olefins (e.g., ethylene, propylene, and C4) and pyrolytic gasoline. During these cracking processes, a recycle stream of crude hydrocarbons is often formed as a byproduct.

[0006] The presence of isobutene, butadiene, 1-butene, 2-butene, and other components in crude hydrocarbon streams can allow for the formation of valuable alcohols and fuel additives. However, converting crude hydrocarbon streams into fuel additive products can often be inefficient and costly. Furthermore, the final product specifications of such alcohols may be suboptimal and may fail to meet market quality requirements. For example, alcohol products may have high levels of impurities and high Reid vapor pressures, such as greater than 2.0 psi (greater than 10 kPa, greater than 12 kPa, greater than 13 kPa, greater than 14 kPa), and low octane numbers (e.g., Research Octane Number (RON) of 82), all of which are associated with poor product quality. Any improvement in these specifications and / or process efficiency could yield more valuable fuel additive products.

[0007] Therefore, there is a need for an efficient method for producing fuel additives that can utilize crude hydrocarbon streams and produce final products with low impurities and high performance specifications. Summary of the Invention

[0008] In various embodiments, methods for preparing fuel additives are disclosed.

[0009] A method for producing a fuel additive includes: passing a feed stream containing C4 hydrocarbons through a methyl tert-butyl ether unit to generate a first process stream; passing the first process stream through a selective butadiene hydrogenation unit, which converts greater than or equal to 90 wt% of butadiene into 1-butene and 2-butene, preferably greater than or equal to 93%, more preferably greater than or equal to 94%, and more preferably greater than or equal to 95%, to generate a second process stream; passing the second process stream through a hydration unit to generate a third process stream and the fuel additive; passing the third process stream through a total hydrogenation unit to generate a hydrogenated stream; and passing the hydrogenated stream through a cracker unit.

[0010] A method for producing a fuel additive includes: passing a feed stream containing hydrocarbons through a cracker unit to generate a cracked stream; passing the cracked stream through a methyl tert-butyl ether (MTBE) unit to generate a first process stream, wherein methanol and isobutene are present in the MTBE unit at a molar ratio of 1 mole of isobutene to 0.1 moles to 5 moles of methanol; extracting MTBE product from the MTBE unit; passing the first process stream through a selective butadiene hydrogenation unit to generate a second process stream; and passing the second process stream through a hydration unit to generate a third process stream, wherein... The temperature within the hydration unit is 30°C to 190°C, the pressure within the hydration unit is 500 kPa to 20,000 kPa, and any butene present in the third process stream at or above 0.10% is converted to butanol within the hydration unit; fuel additive products are extracted from the hydration unit, wherein the fuel additive products include 1-butanol, 2-butanol, tert-butanol, diisobutene, or combinations thereof; the third process stream is passed through the total hydrogenation unit to produce a hydrogenation process stream; and the hydrogenation process stream is recycled to the cracker unit.

[0011] These and other features and characteristics are described in more detail below. Attached Figure Description

[0012] The following is a brief description of the accompanying drawings, wherein the same element numbers are the same and these elements are given for the purpose of illustrating the exemplary embodiments disclosed herein and not for the purpose of limiting them.

[0013] Figure 1 This is a schematic diagram showing the sequence of units used in the production of fuel additives. Detailed Implementation

[0014] This paper discloses an efficient method for producing fuel additives that utilizes crude hydrocarbon streams and produces a final product with low impurities and high performance specifications. For example, the method disclosed herein can provide a unique sequence of unit operations that converts crude hydrocarbons into valuable fuel additives, such as alcohol fuel additives. This unique sequence can significantly improve the efficiency of the process, thereby reducing total investment costs. The final fuel additive product may have an amount of 1-butanol, 2-butanol, tert-butanol, C4-dimer, or combinations thereof. For example, the final fuel additive product may have a C4-dimer level containing 0.01 wt% to 50 wt% of trimethylpentane, diisobutylene, 2,2,4-trimethylpentane, 2,3,3-trimethylpentane, or combinations thereof based on the total weight of the fuel additive, a high octane number (e.g., greater than or equal to 85 RON, or greater than or equal to 87 RON), and a low Red vapor pressure greater than or equal to 55 kPa. For example, trimethylpentane may be present in an amount of 0.1 to 25 wt%, for example, 1 to 20 wt%. Any or all of these properties can be associated with high performance and high market value. The methods disclosed herein can also be used to produce byproducts in conjunction with fuel additive products. For example, methyl tert-butyl ether (MTBE) products can be produced in conjunction with fuel additives, thereby maximizing the efficiency and productivity of the process.

[0015] The system used in this method may include a methyl tert-butyl ether synthesis unit capable of processing butadiene concentrations up to 45 wt% to produce methyl tert-butyl ether using isobutene along with an external methanol stream. Such a product can be used as a fuel additive. A selective hydrogenation unit can be used to help maximize the production of 1-butene and 2-butene from butadiene present in the feed stream. For example, after conversion to 1-butene and 2-butene, less than or equal to 10 wt%, such as less than or equal to 5 wt%, of butadiene may remain in the feed stream. Among other components, the fuel additive may be made from 1-butene and 2-butene, and a minimum amount (e.g., 0.1-15 wt%) of isobutene. The method disclosed herein can provide two fuel additives, methyl tert-butyl ether, and another gasoline octane booster comprising a mixed alcohol (i.e., C4 alcohol).

[0016] This method may include passing a feed stream of crude hydrocarbons through an MTBE unit to generate a first process stream. The feed stream may first be cracked in a cracker unit to generate a cracked stream, which is then extracted from the cracker unit and passed to the MTBE unit. The MTBE unit can convert isobutene present in the feed stream into MTBE products. The first process stream can then be passed through a selective hydrogenation unit, such as a selective butadiene hydrogenation unit, to generate a second process stream. This selective hydrogenation unit can convert butadiene present in the first process stream into 1-butene and 2-butene. For example, converting greater than or equal to 90 wt% of butadiene present in the first process stream into 1-butene and 2-butene, for example, greater than or equal to 93%, for example, greater than or equal to 95%, for example, greater than or equal to 95%. As discussed further in detail herein, the selectivity of 1-butene and 2-butene can be adjusted by carbon monoxide injection.

[0017] Minimizing butadiene in this method can increase desired product specifications, such as octane number. A second process stream can then be generated through a hydration unit to produce fuel additives, such as alcohol fuel additives, or blended alcohol fuel additives, such as C4 alcohol fuel additives. A third process stream can also be generated in the hydration unit, which can be recycled through another hydrogenation unit, such as a C4 hydrogenation unit or a total hydrogenation unit. The hydrogenation stream can be formed in the hydrogenation unit and recycled to a point before the MTBE unit, for example, recycled to a cracking unit, which could be a steam cracking unit. This method can maximize the product quality of the fuel additive product while also efficiently producing additional MTBE products, which can also be used as fuel additives.

[0018] The methods disclosed herein may include passing a feed stream through an olefin production unit, such as a hydrocarbon cracking unit, or a catalytic and / or steam cracking unit, such that the source of the feed stream may include products of an olefin cracking process and / or an olefin production process. The feed stream may contain hydrocarbons, such as C4 hydrocarbons. Additional hydrocarbons, such as C2 and C3 hydrocarbons, may also be fed into the olefin production unit. The feed stream can then be withdrawn from the olefin production unit as a crude C4 hydrocarbon stream. Process streams produced by the olefin production unit may include propane, propylene, ethylacetylene, vinylacetylene, 1,3-butadiene, 1,2-butadiene, isobutene, cis-2-butene, trans-2-butene, 1-butene, isobutane, n-butane, or combinations thereof. When withdrawn from the steam cracking unit, the total C4 olefin content in the feed stream may be greater than or equal to 90 wt%, and the feed stream may contain greater than or equal to 40 wt% isobutene. When withdrawn from the fluidized catalytic cracking unit, the total C4 olefin content in the feed stream can be greater than or equal to 50 wt%, and the stream can contain greater than or equal to 30 wt% isobutylene.

[0019] The cracked stream drawn from the cracker unit can then pass through the MTBE unit. Methanol can be fed into the MTBE unit via a methanol stream. The MTBE unit converts isobutylene present in the cracked stream into MTBE product. The cracked stream can be contacted with methanol and a catalyst, such as an acidic ion exchange resin catalyst, within the MTBE unit. The molar ratio of methanol to isobutylene can be from 1.0 mol isobutylene to 0.05 mol to 10.0 mol methanol, for example, from 1 mol isobutylene to 0.1 mol to 5.0 mol methanol, or from 1 mol isobutylene to 0.5 mol to 2.0 mol methanol within the MTBE unit. MTBE product can be drawn from the MTBE unit via the MTBE product stream. The purity of the MTBE product can be greater than or equal to 90%. The conversion rate from isobutylene to MTBE within the MTBE unit can be greater than or equal to 75%, for example, greater than or equal to 85%, for example, greater than or equal to 95%.

[0020] A first process stream can be drawn from an MTBE unit with a reduced isobutylene content. For example, the first process stream leaving the MTBE unit may contain less than or equal to 5 wt% isobutylene. The temperature within the hydration unit can be from 15°C to 150°C, for example, from 35°C to 125°C. The pressure within the MTBE unit can be from 500 kPa to 2800 kPa, for example, from 1000 kPa to 2000 kPa, for example, from 1500 kPa. The MTBE unit can process streams containing butadiene in amounts up to 45 wt%. This can be achieved through process modifications and the insertion of chemicals at selected locations in the scheme to avoid polymerization, as further described below.

[0021] The etherification of isobutylene can be carried out in two reaction stages: a) a first reactor consisting of a water-cooled tubular reactor (WCTR), and b) a second adiabatic reactor. The reaction can be carried out in the liquid phase over a sulfonic acid resin catalyst, where the feed flows upward through the reactor tubes, while the reaction mixture can enter under pressure to ensure that the mixture is also kept in the liquid phase, where the maximum temperature is also reached. The reaction can proceed almost isothermally, and the heat of reaction can be removed by circulating warm water through the shell side of the reactor in a co-current flow within a closed loop. The reaction products leaving the reactor can be fed into a fractionation column, where MTBE products can be recovered from the bottom. Inhibitors (e.g., a mixture of tert-butylcatechol (TBC) and methanol) can be injected into the reactor and at the top of the column.

[0022] The first process stream exiting the MTBE unit then passes through a selective hydrogenation unit. For example, the hydrogenation unit could be a selective butadiene hydrogenation unit. This selective hydrogenation unit can convert butadiene present in the process stream into 1-butene and 2-butene, such as cis-2-butene and trans-2-butene. The conversion rate from butadiene to 1-butene, cis-2-butene, and trans-2-butene can be greater than or equal to 90 wt%, preferably greater than or equal to 93%, more preferably greater than or equal to 94%, and more preferably greater than or equal to 95% of the butadiene is converted to 1-butene and 2-butene. Propylene, ethylacetylene, and vinylacetylene present in the first process stream can also be hydrogenated within the selective hydrogenation unit. The hydrogenation unit can include multiple reactors in series; for example, the hydrogenation unit can include three reactor stages. The first two reactor stages can convert butadiene present in the first process stream into 2-butene, cis-2-butene, and trans-2-butene. The first two reactor stages can contain a selective hydrogenation catalyst. For example, the hydrogenation catalyst can contain palladium having an aluminum base. The hydrogenation catalyst may include platinum, rhodium, palladium, ruthenium, cobalt, nickel, copper, or combinations thereof. The catalyst may be the same for the first two reactor stages. Hydrogen may be injected into the first process stream prior to the first reactor stage.

[0023] The final hydrogenation reaction from diene to the desired mono-olefin product can be achieved in the third reactor. Carbon monoxide can be injected into the third reactor to weaken the catalyst and minimize the isomerization reaction from 1-butene to 2-butene. During normal operation, the desired carbon monoxide injection rate can be 0.2 parts per million (ppm) of the feed stream to the third reactor. This rate can be increased if excess 1-butene is lost to 2-butene. The first process stream can then be withdrawn from the selective hydrogenation unit. The operating conditions of the selective hydrogenation unit are shown in Table 1. Temperatures are reported in degrees Celsius and pressures in pounds per square inch (psi) and kilopascals (kPa).

[0024]

[0025] The second process stream exiting the selective hydrogenation unit can then be passed through a hydration unit to produce a third process stream and a fuel additive, such as an alcohol additive, a mixed alcohol fuel additive, or a C4 alcohol fuel additive. The second process stream entering the hydration unit may contain less than or equal to 5 wt% butadiene, for example, less than or equal to 3 wt%, or less than or equal to 1 wt%. The fuel additive product can be extracted from the hydration unit via a product stream. Water can be supplied to the hydration unit via a water stream. The hydration unit may include an oscillating baffle reactor, a fixed-bed reactor, a membrane integrated reactor, or a combination thereof. The hydration unit can convert butene present in the second process stream to butanol. For example, greater than or equal to 0.1 wt% butene present in the feed stream can be converted to butanol within the hydration unit, for example, greater than or equal to 30 wt%, for example, greater than or equal to 50 wt%, or for example, greater than or equal to 90 wt%. In the hydration unit, the second process stream may be contacted with water and a catalyst. For example, the catalyst may contain phosphoric acid, hypophosphoric acid, an ion exchange resin, sulfur, polystyrene, polymers, niobium oxide, or a combination thereof. Water and butene can exist in a hydration unit in a molar ratio of 1.0 mole of water to 1 to 20 moles of butene, for example, 1 mole of water to 5 to 10 moles of butene. The temperature within the hydration unit can be from 30°C to 250°C, for example, from 100°C to 200°C. The pressure within the hydration unit can be from 500 kPa to 20,000 kPa, for example, from 5,000 kPa to 10,000 kPa, for example, 7,500 kPa.

[0026] The fuel additive product may contain 1-butanol, 2-butanol, tert-butanol, C4-dimer, or combinations thereof. For example, the C4-dimer may contain trimethylpentane, diisobutylene, 2,2,4-trimethylpentane, 2,3,3-trimethylpentane, or combinations thereof. The fuel additive product may contain greater than or equal to 0.1 wt% of trimethylpentane, for example, greater than or equal to 0.5 wt%, for example, greater than or equal to 0.1 wt%. In some cases, the fuel additive product may contain 10 wt% to 20 wt% of trimethylpentane. The research octane number of the fuel additive product may be greater than or equal to 80, for example, greater than or equal to 82, for example, greater than or equal to 85, for example, greater than or equal to 91, for example, greater than or equal to 95. Motor octane number can be greater than or equal to 70, for example, greater than or equal to 75, for example, greater than or equal to 80, for example, greater than or equal to 82, for example, greater than or equal to 85, for example, greater than or equal to 90, for example, greater than or equal to 95.

[0027] Octane rating is a standard metric used to measure the performance of an engine or fuel. A higher octane rating means the fuel can withstand a greater degree of compression before ignition. Fuels with higher octane ratings are typically used in high-performance gasoline engines that require higher compression ratios. Diesel engines may prefer lower octane fuels because they don't compress fuel; instead, they compress only air and then inject fuel into the air heated by compression. Gasoline engines rely on the air and fuel compressed together as a mixture to ignite, using a spark plug at the end of the compression stroke. As a result, the high compressibility of fuel is a consideration for gasoline engines.

[0028] Research octane rating (RIA) is determined by running fuel in a test engine at a variable compression ratio at 600 rpm under controlled conditions and comparing the results to those of mixtures of isooctane and n-heptane. Higher octane ratings provide a greater amount of energy required to initiate combustion. Fuels with higher octane ratings are less prone to auto-ignition and, in the absence of auto-ignition, can withstand higher temperature rises during the compression stroke of an internal combustion engine.

[0029] Red vapor pressure is used to measure the volatility of gasoline and is defined as the absolute vapor pressure applied by a liquid at 37.8°C by ASTM D-323. In addition to liquefied petroleum gas (LPG), this test measures the vapor pressure of gasoline, crude oil, and other volatile petroleum products. Red vapor pressure is measured in kilopascals (kPa) and represents the relative pressure relative to atmospheric pressure, as ASTM D-323 measures the gauge pressure of samples in a non-vacuum chamber. Higher levels of vaporization are desired for winter condensation and operation, while lower levels are desired to avoid vapor lock during hot summer months. When vapor is present in the fuel lines, fuel cannot be pumped, and winter starts will be difficult if the liquid gasoline in the combustion chamber has not yet evaporated. Therefore, this means that oil producers adjust Red vapor pressure seasonally to maintain the reliability of gasoline engines.

[0030] The Reid vapor pressure of the fuel additive product can be less than or equal to 75 kPa, for example, less than or equal to 55 kPa, or for example, less than or equal to 25 kPa. The fuel additive product may also contain less than or equal to 1 wt% of impurities, such as dienes. For example, the fuel additive product may contain less than or equal to 0.1 wt% of butene dimer.

[0031] The third process stream may contain 1-butene, 2-butene, isobutane, isobutene, n-butane, or combinations thereof. The third process stream exiting the hydration unit may pass through a hydrogenation unit, such as a C4 hydrogenation unit, to produce a hydrogenated stream, wherein any butene present in the third process stream within the hydrogenation unit at a rate greater than or equal to 0.01% is converted to butane, preferably wherein the amount of butane in the hydrogenated stream is greater than or equal to 90%.

[0032] In some embodiments, the hydrogenation unit is a total hydrogenation unit. The total hydrogenation unit converts C4 olefins into saturated hydrocarbons before being recycled to the steam cracker. Optionally, the hydrogenation stream can be recycled to the steam cracker unit and / or the initial feed stream.

[0033] A more complete understanding of the components, processes, and apparatus disclosed herein can be obtained by referring to the accompanying drawings. These drawings (also referred to herein as “Figures”) are merely schematic diagrams for convenience and ease of illustrating this disclosure and are therefore not intended to indicate the relative size and dimensions of the apparatus or its components and / or to define or limit the scope of the exemplary embodiments. Although specific terms are used in the following description for clarity, these terms are only intended to denote specific structures selected for illustration in the drawings and are not intended to define or limit the scope of this disclosure. In the following drawings and description, it should be understood that the same numerical designations refer to components having the same function.

[0034] Now refer to Figure 1 This simplified schematic diagram illustrates a unit sequence 10 used in a method for producing fuel additives. Sequence 10 may include passing a first feed stream 12 containing hydrocarbons through a hydrocarbon cracking unit 14. For example, the hydrocarbon cracking unit 14 may be a steam cracking and / or catalytic cracking unit.

[0035] The cracking process stream 16 can then be extracted from the cracking unit 14. The cracking process stream may contain crude hydrocarbons, such as C4 hydrocarbons. The cracking process stream 16 can then pass through the MTBE unit 18. Methanol can be fed through the MTBE unit 18 via stream 20. The MTBE unit 18 can convert the isobutylene present in the second process stream 16 into MTBE product 22, which can be extracted from the MTBE unit 18.

[0036] A first process stream 24, containing a reduced isobutene content, can then be drawn from MTBE unit 18. The first process stream 24 can then be passed through a selective hydrogenation unit 26. Hydrogenation unit 26 can be a selective butadiene hydrogenation unit and may include multiple reactors in series. Hydrogenation unit 26 can convert the butadiene present in stream 24 into 1-butene and 2-butene, as described in detail previously herein.

[0037] Then, a second process stream 28 can be drawn from the hydrogenation unit 26 and passed through the hydration unit 30 to produce a fuel additive 46, such as an alcohol fuel additive. The fuel additive 46 can be drawn from the hydration unit 30. Water can be fed into the hydration unit 30 via stream 44.

[0038] A third process stream 32 can be drawn from the hydration unit 30 and recycled back to the initial feed stream 12. Optionally, the third process stream 32 can pass through a total hydrogenation unit 42, such as a C4 hydrogenation unit, before returning to the feed stream 12. A hydrogenated stream 48 can be generated in the hydrogenation unit 42. The total hydrogenation unit 42 can convert 1-butene and 2-butene present in the third process stream 32 into n-butane and isobutane. The resulting hydrogenated stream 48 can then be combined with the feed stream 12. Optionally, the hydrogenated stream 48 can be fed into a cracking unit, such as a steam cracking unit.

[0039] The methods disclosed in this paper include at least the following aspects: Aspect 1: A method for producing a fuel additive, comprising: passing a feed stream containing C4 hydrocarbons through a methyl tert-butyl ether unit to generate a first process stream; passing the first process stream through a selective butadiene hydrogenation unit, which converts greater than or equal to 90 wt% of butadiene into 1-butene and 2-butene, preferably greater than or equal to 93%, more preferably greater than or equal to 94%, and more preferably greater than or equal to 95%, to generate a second process stream; passing the second process stream through a hydration unit to generate a third process stream and a fuel additive; passing the third process stream through a total hydrogenation unit to generate a hydrogenated stream; and passing the hydrogenated stream through a cracker unit.

[0040] Aspect 2: According to the method of Aspect 1, the source of the feed stream includes products of the olefin cracking process and / or the olefin production process.

[0041] Aspect 3: The method according to any of the preceding aspects, wherein the feed stream comprises propane, propylene, ethyl acetylene, vinyl acetylene, 1,3-butadiene, 1,2-butadiene, isobutene, cis-2-butene, trans-2-butene, 1-butene, isobutane, n-butane, or combinations thereof.

[0042] Aspect 4: The method according to any of the foregoing aspects further includes contacting the feed stream with a catalyst within the methyl tert-butyl ether unit, wherein the catalyst comprises an acidic ion exchange resin.

[0043] Aspect 5: The method according to any of the preceding aspects, wherein the temperature within the methyl tert-butyl ether unit is from 15°C to 150°C, and the pressure within the methyl tert-butyl ether unit is from 500 kPa to 2800 kPa.

[0044] Aspect 6: The method according to any of the preceding aspects, wherein methanol and isobutylene are present in the methyl tert-butyl ether unit in a molar ratio of 1 mole of isobutylene to 0.1 moles to 5 moles of methanol.

[0045] Aspect 7: The method according to any of the preceding aspects, wherein any isobutylene present in the feed stream at a concentration greater than or equal to 0.1 wt% is converted into methyl tert-butyl ether within the methyl tert-butyl ether unit.

[0046] Aspect 8: The method according to aspect 7 further includes extracting the methyl tert-butyl ether product from the methyl tert-butyl ether unit.

[0047] Aspect 9: The method according to any of the preceding aspects, wherein the second process stream contains less than or equal to 5.0 wt%, preferably less than or equal to 3.0 wt%, more preferably less than or equal to 1.0 wt% butadiene before passing through the hydration unit.

[0048] Aspect 10: The method according to any of the preceding aspects further includes contacting a second process stream with a catalyst within a hydration unit, wherein the catalyst comprises phosphoric acid, hypophosphoric acid, an ion exchange resin, sulfur, polystyrene, a polymer, niobium oxide, or a combination thereof.

[0049] Aspect 11: The method according to any of the preceding aspects, wherein the temperature within the hydration unit is 30°C to 250°C, and the pressure within the hydration unit is 500 kPa to 20,000 kPa.

[0050] Aspect 12: The method according to any of the preceding aspects, wherein any butene present in the second process stream of greater than or equal to 0.10% is converted to butanol in the hydration unit, preferably 1% to 90% of any butadiene present in the second process stream is converted to butanol in the hydration unit.

[0051] Aspect 13: The method according to any of the foregoing aspects further includes extracting fuel additive products from the hydration unit.

[0052] Aspect 14: The method according to aspect 13, wherein the fuel additive product includes 1-butanol, 2-butanol, tert-butanol, diisobutylene, or combinations thereof.

[0053] Aspect 15: According to the method of aspect 13, wherein the research octane number of the fuel additive product is greater than or equal to 80, preferably greater than or equal to 82, more preferably greater than or equal to 85.

[0054] Aspect 16: According to the method of aspect 13, the Red vapor pressure of the fuel additive product is less than or equal to 55 kPa, preferably less than or equal to 45 kPa, more preferably less than or equal to 35 kPa, and most preferably less than or equal to 25 kPa.

[0055] Aspect 17: According to the method of any of the preceding aspects, any butene present in the third process stream of greater than or equal to 0.01%, preferably greater than or equal to 90%, is converted into butane in the hydrogenation unit.

[0056] Aspect 18: A method for producing a fuel additive, comprising: passing a feed stream containing hydrocarbons through a cracker unit to generate a cracked stream; passing the cracked stream through a methyl tert-butyl ether (MTBE) unit to generate a first process stream, wherein methanol and isobutylene are present in the MTBE unit in a molar ratio of 1 mole of isobutylene to 0.1 mole to 5 moles of methanol; extracting MTBE product from the MTBE unit; passing the first process stream through a selective butadiene hydrogenation unit to generate a second process stream; and passing the second process stream through a hydration unit to generate a third process stream. The process stream is configured such that the temperature within the hydration unit is between 30°C and 190°C, and the pressure within the hydration unit is between 500 kPa and 20,000 kPa, wherein any butene present in the third process stream at or above 0.10% is converted to butanol within the hydration unit; fuel additive products are extracted from the hydration unit, wherein the fuel additive products include 1-butanol, 2-butanol, tert-butanol, diisobutene, or combinations thereof; the third process stream is passed through the total hydrogenation unit to produce a hydrogenation process stream; and the hydrogenation process stream is recycled to the cracker unit.

[0057] Generally, the present invention may alternatively include, constitute, or substantially constitute any suitable components disclosed herein. The present invention may additionally or alternatively be formulated free from or substantially free from any components, materials, ingredients, adjuvants, or substances used in prior art compositions or otherwise not essential for achieving the function and / or purpose of the present invention. The endpoints of all ranges for the same component or property are inclusive and independently combinable (e.g., the range “less than or equal to 25 wt%, or 5 wt% to 20 wt%” includes the endpoints of the range “5 wt% to 25 wt%” and all intermediate values). Disclosure of a narrower or more specific group, in addition to a broader range, is not a waiver of a broader or larger group. Furthermore, the terms “first,” “second,” etc., herein do not indicate any order, quantity, or importance, but are used to indicate one element with another. The terms “a,” “an,” and “the” herein do not indicate a limitation of quantity and should be construed as encompassing both singular and plural unless otherwise stated herein or the context clearly contradicts it. “Or” means “and / or.” As used herein, the suffix "(s)" is intended to include both the singular and plural forms of the terms it modifies, thereby including one or more of those terms (e.g., a membrane includes one or more membranes). References throughout the specification to "one embodiment," "another embodiment," "an embodiment," etc., mean that a particular element (e.g., component, structure, and / or feature) described in connection with an embodiment is included in at least one embodiment described herein and may or may not exist in other embodiments. Furthermore, it should be understood that the elements described in the various embodiments can be combined in any suitable manner.

[0058] The modifier “approximately” used with quantity includes a value and has the meaning indicated by the context (e.g., including the degree of error associated with the measurement of a particular quantity). The symbol “ +"10%" indicates that the indicated measurement can be from a quantity minus 10% to a quantity plus 10% of the value. Unless otherwise stated, the terms "before," "after," "bottom," and / or "top" used herein are for ease of description only and are not limited to any particular location or spatial orientation. "Optional" or "optionally" means that an event or situation subsequently described may or may not occur, and the description includes instances in which the event occurs and instances in which the event does not occur. Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. "Combination" includes blends, mixtures, alloys, reaction products, etc. In a list of alternative substances, "combination of them" means that the combination may include at least one element from the list with one or more unnamed similar elements. Additionally, "at least one" means that the list includes each element individually, as well as combinations of two or more elements from the list, and combinations of at least one element from the list with unnamed similar elements.

[0059] All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if any terminology in this application contradicts or conflicts with terminology in the incorporated references, the terminology in this application shall take precedence over the conflicting terminology in the incorporated references.

[0060] Although specific embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that may be conceived by the applicant or those skilled in the art, or that are not currently foreseen. Therefore, the appended claims, as filed and possibly modified thereto, are intended to include all such alternatives, modifications, variations, improvements, and substantial equivalents.

Claims

1. A method for producing fuel additives, comprising: A feed stream containing C4 hydrocarbons and methanol is passed through a methyl tert-butyl ether unit to produce a first process stream and a methyl tert-butyl ether product, wherein the feed stream contains butadiene and isobutylene; The first process stream is passed through a selective butadiene hydrogenation unit, which converts 90 wt% or more of the butadiene in the first process stream into 1-butene and 2-butene to generate a second process stream. The selective butadiene hydrogenation unit includes a first reactor stage, a second reactor stage, and a third reactor stage connected in series. The first reactor stage and the second reactor stage convert at least a portion of the butadiene remaining in the first process stream into 2-butene, and the hydrogenation reaction is carried out in the third reactor stage to generate the second process stream. The second process stream and water are passed through a hydration unit to produce a third process stream and the fuel additive, wherein the second process stream contains less than or equal to 5.0 wt% butadiene before passing through the hydration unit, and wherein more than or equal to 50 wt% of butadiene present in the second process stream is converted to butanol in the hydration unit. The third process stream is passed through the overall hydrogenation unit to generate a hydrogenated stream; as well as The hydrogenated stream is passed through the cracker unit. The temperature within the methyl tert-butyl ether unit is from 15°C to 150°C, and the pressure within the methyl tert-butyl ether unit is from 500 kPa to 2800 kPa. The first process stream exiting the methyl tert-butyl ether unit contains less than or equal to 5 wt% isobutylene.

2. The method of claim 1, wherein the source of the feed stream comprises products of an olefin cracking process and / or an olefin production process; and in, The first reactor stage operates at a temperature of 40°C to 70°C and a pressure of 140 to 400 psig, the second reactor stage operates at a temperature of 50°C to 60°C and a pressure of 140 to 400 psig, and the third reactor stage operates at a temperature of 60°C to 80°C and a pressure of 250 to 270 psig.

3. The method according to claim 1 or claim 2, wherein the feed stream comprises propane, propylene, ethylacetylene, vinylacetylene, 1,3-butadiene, 1,2-butadiene, isobutene, cis-2-butene, trans-2-butene, 1-butene, isobutane, n-butane, or combinations thereof; and The butadiene content discharged from the third reactor stage is less than 0.01%.

4. The method according to claim 1 or claim 2, further comprising contacting the feed stream with a catalyst within the methyl tert-butyl ether unit, wherein the catalyst comprises an acidic ion exchange resin.

5. The method according to claim 1 or claim 2, wherein methanol and isobutylene are present in the methyl tert-butyl ether unit in a molar ratio of 1 mole of isobutylene to 0.1 moles to 5 moles of methanol.

6. The method according to claim 1 or claim 2, wherein any isobutylene present in the feed stream of greater than or equal to 75 wt% is converted into methyl tert-butyl ether within the methyl tert-butyl ether unit.

7. The method according to claim 1 or claim 2, further comprising extracting the methyl tert-butyl ether product from the methyl tert-butyl ether unit; and The purity of the methyl tert-butyl ether product is greater than or equal to 90%.

8. The method according to claim 1 or claim 2, wherein the second process stream contains less than or equal to 1.0 wt% butadiene prior to passing through the hydration unit.

9. The method of claim 1 or claim 2, further comprising contacting the second process stream with a catalyst within the hydration unit, wherein the catalyst comprises phosphoric acid, hypophosphoric acid, an ion exchange resin, sulfur, polystyrene, a polymer, niobium oxide, or a combination thereof.

10. The method according to claim 1 or claim 2, wherein the temperature within the hydration unit is from 30°C to 250°C, and the pressure within the hydration unit is from 500 kPa to 20,000 kPa.

11. The method according to claim 1 or claim 2, wherein any butene present in the second process stream of greater than or equal to 90% is converted into butanol within the hydration unit.

12. The method according to claim 1 or claim 2, further comprising extracting fuel additive products from the hydration unit.

13. The method of claim 12, wherein the fuel additive product comprises 1-butanol, 2-butanol, tert-butanol, diisobutylene, or a combination thereof.

14. The method of claim 12, wherein the research octane number of the fuel additive product is greater than or equal to 80.

15. The method of claim 12, wherein the red vapor pressure of the fuel additive product is less than or equal to 55 kPa.

16. The method according to claim 1 or claim 2, wherein any butene present in the third process stream of greater than or equal to 90% is converted into butane within the hydrogenation unit.

17. A method for producing fuel additives, comprising: A feed stream containing hydrocarbons is passed through a cracker unit to generate a cracked stream; The cracking stream is passed through a methyl tert-butyl ether unit to produce a first process stream, wherein methanol and isobutylene are present in the methyl tert-butyl ether unit in a molar ratio of 1 mole of isobutylene to 0.1 moles of methanol to 5 moles of methanol. Extract the methyl tert-butyl ether product from the methyl tert-butyl ether unit; The first process stream is passed through a selective butadiene hydrogenation unit, which converts 90 wt% or more of the butadiene in the first process stream into 1-butene and 2-butene, and generates a second process stream. The selective butadiene hydrogenation unit includes a first reactor stage, a second reactor stage, and a third reactor stage in series. The first reactor stage and the second reactor stage convert at least a portion of the butadiene remaining in the first process stream into 2-butene, and the hydrogenation reaction is carried out in the third reactor stage to generate the second process stream. The second process stream and water are passed through a hydration unit to produce a third process stream, wherein the temperature within the hydration unit is 30°C to 190°C and the pressure within the hydration unit is 500 kPa to 20,000 kPa, wherein any butene present in the second process stream of greater than or equal to 90% is converted to butanol within the hydration unit, wherein the second process stream contains less than or equal to 1.0 wt% butadiene prior to passing through the hydration unit; Fuel additive products are extracted from the hydration unit, wherein the fuel additive products comprise 1-butanol, 2-butanol, tert-butanol, diisobutylene, or combinations thereof. The third process stream is passed through the total hydrogenation unit to produce a hydrogenation process stream, wherein any butene present in the third process stream of greater than or equal to 90% is converted into butane within the total hydrogenation unit; as well as The hydrogenation process stream is recycled to the cracker unit; The fuel additive product comprises 1 to 25 wt% trimethylpentane, and the fuel additive product contains less than or equal to 1 wt% impurities; and Carbon monoxide is injected into the third reactor at a rate of two parts per million or more of the reactor stage feed flow into the third reactor stage. The first reactor stage operates at a temperature of 40°C to 70°C and a pressure of 140 to 400 psig, the second reactor stage operates at a temperature of 50°C to 60°C and a pressure of 140 to 400 psig, and the third reactor stage operates at a temperature of 60°C to 80°C and a pressure of 250 to 270 psig. The temperature within the methyl tert-butyl ether unit is from 15°C to 150°C, and the pressure within the methyl tert-butyl ether unit is from 500 kPa to 2800 kPa. The first process stream exiting the methyl tert-butyl ether unit contains less than or equal to 5 wt% isobutylene.

Images