Integrated process for producing phenol from coal-derived liquids
Through integrated dealkylation and alkyl transfer methods, the alkyl phenol in the coal-derived liquid is converted into phenol and the production of alkyl benzene is reduced, which solves the problem of long-chain alkyl phenol conversion in the prior art and realizes phenol Maximize yields and equipment optimization.
Patent Information
- Application Number
- CN202280093685.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2022-03-17
- Publication Date
- 2024-12-13
AI Technical Summary
The prior art is difficult to effectively convert long-chain alkyl phenols in coal-derived liquids into more valuable products such as phenol, and the alkyl transfer method produces a large number of low-value alkyl benzene, and the equipment size and cost are not suitable.
Through integrated dealkylation and alkyl transfer methods, the alkyl phenol in the coal-derived liquid is first converted to phenol by dealkylation, and then alkyl transfer is performed using benzene or toluene to produce more phenol and reduce alkyl The generation of polybenzene is optimized to reduce costs.
Maximizes the yield of phenol, reduces the production of alkylbenzene, reduces the equipment size and toluene consumption, and improves the economic and efficiency of the process.
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Figure CN119137090A_ABST
Abstract
Description
[0001] Coal-derived liquids from coal gasification and coking plants contain large amounts of valuable phenolic compounds, including phenol, cresols, and xylenols, as well as less desirable long-chain alkylphenols. See, for example, Junmin Zhang, Gong Liu, "Comprehensive Utilization of Low-temperature Coal Tar", Coal Conversion, 92-96, 33 (2010); Bai, Yang Zhang, Libin Wang, Sij ian Qu, "The Separation of GroupComposition by Column Chromatography and GC / MS Analysis" Clean CoalTechnology, 59-62, 16 (2010); Xianglan Li, Xintao Cui, Yongfa Zhang, "Analysis of LoW Temperature Coal Tar in Inner Mongolia Lignite Briquette by GC-MS", Analytical Instrument, 17-25, 3(2012); Xuezhi Liu, Pang Jin, “Study on the TarStructure and Nature if Pressurized Pyrolysis for Tianzhu Coal in Gansu”, Coal Conversion, 82-88, 17 (1994) and https: / / www.dakotagas.com / products / chemicals-and-fuels / dephenolized-cresylic-acid. Long-chain alkylphenols have an alkyl group containing 2 or more carbon atoms (e.g., ethylphenol, propylphenol, butylphenol, methylethylphenol, etc.).
[0002] Long chain alkylphenols can be converted to phenol and ethylene and / or propylene by dealkylation. The catalytic vapor phase hydrodealkylation of low temperature tar acid fractions (170°C to 270°C) to low boiling phenols was studied over a chromium oxide-alumina catalyst at atmospheric pressure in a flow system at a temperature range of 480-650°C over a wide range of space velocities. See KK Tiwari, SN Banerji, Asit Bhattacharjee and RN Bhattacharya, "Catalytic Hydrodealkylation of Tar Acids", Applied Catalysis, 39-51, 45 (1988).
[0003] As described in Danny Verboekend, Yuhe Liao, Wouter Schutyser and -Bert F. Sels, "Alkylphenols to phenol and olefins by zeolite catalysis: A pathway to valorize raw and fossilized lignocellulose", Green Chem., 2016 (1), 18, 297-306; and Yuhe Liao, Ruyi Zhong, Ekaterina Makshina et al., "Propylphenol to Phenol and Propylene over Acidic Zeolites: Role of Shape Selectivity and Presence of Steam", ACS Catal. 2018, 8, 9, 7861-7878, at 600 ° C, the phenol yield of the liquid product of different fractions ranged from 26.8 wt % to 55.2 wt %. However, the phenol in the feed itself can also affect the yield, leading to erroneous results. Therefore, pre-separation may be required. Ethylphenol and propylphenol can be converted into related basic chemicals phenol and the corresponding olefins with high selectivity. Efficient and stable dealkylation (95% selectivity to phenol and propylene) was achieved using ZSM-5 zeolite catalyst and water / steam co-feed.
[0004] Complete conversion of isopropyl phenol can be achieved using Y zeolite at 350 °C with a phenol selectivity of over 99%, as described in Shogo Kumagai, Masaki Asakawa, Tomohito Kameda, Yuko Saito, Atsushi Watanabe, Chuichi Watanabe, Norio Teramae & Toshiaki Yoshioka, “Selective phenol recovery via simultaneous hydrogenation / dealkylation of isopropyl-and isopropenyl-phenols employing an H2 generator combined with tandem micro-reactor GC / MS”, Scientific Reports, 11-12, 8 (2018).
[0005] Long-chain alkylphenols can undergo transalkylation with aromatic solvents, such as benzene / toluene, to transfer long-chain alkyl groups (ethyl, propyl, butyl, etc.) to obtain phenol and alkylbenzenes. The transalkylation of 4-propylphenol and benzene was studied using HZSM-5 at 350°C. It was found that the main products of benzene transalkylation were n-propylbenzene (58 mol%) and isopropylbenzene (28 mol%). Xiaoming Huang, Jasper M. Ludenhoff, Mike Dirks, Xianhong Ouyang, Michael D. Boot and Emiel J. M. Hensen, "Selective Production of Biobased Phenol from Lignocellulose Derived Alkylmethoxyphenols", ACS Catalysis, 11184-11190, 8 (2018).
[0006] Another study on the transalkylation of p-propylphenol with benzene over a zeolite catalyst at 400 ° C and 11.6 MPa showed that the phenol yield could reach 22 mol% after 8 hours of operation. The main product of transalkylation with benzene is alkylbenzene. Takuya Yoshikawa, Takahiro Umezawa, Yuta Nakasaka, and Takao Masuda, "Conversion of alkylpheno1tophenol via transalkylation using zeolite catalysts", Catalysis Today, 110-114, 347 (2020). However, this method is not suitable when the market demand for phenol is higher than alkylbenzene.
[0007] US2020 / 0031741 describes a process for producing xylenes and phenol by transalkylation of coal-derived liquids with benzene and / or toluene. In this process, phenol, xylenols, cresols and long-chain alkylphenols are pre-separated from coal tar. However, it is not desirable to feed cresols to a transalkylation unit to produce phenol and xylenes, since cresols are a more valuable product than phenol. No details are provided on how to handle long-chain alkylphenols.
[0008] WO2020162877 describes another method for producing phenol and xylene from a phenol-containing feed. In this invention, all alkylphenols except phenol are transalkylated by benzene and / or toluene. For the high-value cresol component, there are the same problems as in US2020 / 0031741. In addition, the transalkylation of long-chain alkylphenols requires a large amount of benzene and / or toluene, producing a large amount of alkylbenzene products. The size of the downstream processing equipment is relatively large and not cost-effective.
[0009] WO2020 / 162876 describes an integrated process for dealkylation and transalkylation of cresols from a phenol-containing feed, but the desired product of the process is cresol. Although phenol and cresol are separated in advance, xylenol is sent to dealkylation together with other heavy alkylphenols, which leads to potential cracking of xylenol. In addition, the reactor of the process is large. In addition, some aromatics may be produced during the dealkylation process, and their separation from alkylphenols has not yet been solved.
[0010] Therefore, there remains a need for methods of converting long-chain phenols in coal-derived feeds to more valuable products, such as phenol. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 is a schematic diagram of one embodiment of the method according to the present invention.
[0012] Figure 2is a schematic diagram of another embodiment of the method according to the present invention.
[0013] describe
[0014] A new process for producing phenol, cresols and xylenes from coal-derived feeds has been developed that integrates dealkylation of alkylphenols in coal-derived liquids with transalkylation using benzene and / or toluene. Alkylphenols in coal-derived liquids are converted to phenol by dealkylation. Unconverted alkylphenols and aromatic compounds (such as benzene or toluene) are transalkylated to produce more phenol. Cresols and xylenes may also be produced. These processes maximize phenol product yields and reduce alkylbenzene yields.
[0015] Preliminary work involved the transalkylation of toluene with model components 4-ethylphenol and 2,6-xylenol, and the results showed that the selectivity of alkylbenzenes (xylenes, ethylbenzene, ethyltoluene, etc.) was higher than that of phenol when the molar ratio of toluene / alkylphenol was 6:1. Method simulations showed that toluene transalkylation of alkylphenol compounds from the acid fraction of Xinjiang Hami low / medium coal tar (Xinjiang Hami coal, China) could produce about 56 wt% alkylbenzenes and 11.5 wt% phenol.
[0016] A problem with stand-alone transalkylation processes is that a variety of low-value alkylbenzene compounds, such as ethyltoluene and n-propylbenzene, are produced from long-chain alkylphenols. The market demand for these alkylbenzene products is low. Processes starting with dealkylation reactions make phenol the main product from ethylphenol, propylphenol and ethylmethylphenol, without producing low-value alkylbenzenes. However, xylenols and trimethylphenols are poorly reactive to dealkylation reactions. By integrating transalkylation as a second reaction into the process, xylenols and trimethylphenols can react with toluene to produce phenol, cresols and xylenes. In this way, not only is the generation of less desirable alkylbenzenes avoided, but the reactor size and toluene consumption of the transalkylation reaction are also significantly reduced.
[0017] Additional tests showed that the dealkylation of ethylphenol using HZSM-5 catalyst had higher phenol selectivity.
[0018] By combining the transalkylation of benzene or toluene with dealkylation, the phenol production can be maximized and the alkylbenzene production can be minimized. Long chain alkylphenols (e.g., ethylphenol, propylphenol, butylphenol, etc.) are dealkylated to phenol and olefins. Short chain alkylphenols (having an alkyl group containing one carbon atom, e.g., xylenol, trimethylphenol, etc.) are transalkylated to phenol and cresols, with alkylbenzenes as byproducts.
[0019] The present method combines the dealkylation of long-chain alkylphenols in coal-derived liquids with the subsequent transalkylation of benzene and / or toluene to reduce the generation of undesirable alkylbenzenes. The long-chain alkylphenols in the coal-derived liquids are converted in a dealkylation reaction zone including a dealkylation reactor to produce phenol. Unconverted alkylphenols are fed to a transalkylation reaction zone including a transalkylation reactor together with xylenols and aromatic compounds (e.g., benzene or toluene or a mixture thereof) to produce more phenol. In some embodiments, toluene is selected as a solvent because benzene has a higher toxicity. Unconverted toluene, benzene and other aromatic compounds can be recycled back to the transalkylation reaction zone to reduce the replenishment rate of toluene and / or benzene.
[0020] The present process involves separating phenol and cresols from alkylphenols in coal-derived liquids prior to dealkylation and transalkylation. This prevents the phenol and cresols from being cracked into less valuable products in the dealkylation step and also reduces the size of downstream processes and equipment.
[0021] In one embodiment, the process includes separating xylenols from alkylphenols in the coal-derived liquid prior to dealkylation and transalkylation. This prevents the xylenols from being cracked into less valuable products during the dealkylation step and also reduces the size of downstream processes and equipment.
[0022] One aspect of the present invention is a method for producing phenol from a coal-derived feed. In one embodiment, the method includes: providing an alkylphenol stream comprising an alkylphenol having an alkyl chain of two or more carbon atoms; dealkylating the alkylphenol stream in a first dealkylation reaction zone comprising a first dealkylation reactor under first dealkylation reaction conditions in the presence of a first dealkylation catalyst to produce a first dealkylation effluent stream comprising light hydrocarbons, alkylbenzenes, phenol, cresols, and unconverted alkylphenols; separating the first dealkylation effluent stream into at least a phenol stream comprising phenol and a bottoms stream comprising unconverted alkylphenol in a dealkylation separation zone; transalkylating the bottoms stream and a reactant stream comprising toluene or benzene or both in a first transalkylation reaction zone comprising a first transalkylation reactor under first transalkylation reaction conditions in the presence of a first transalkylation catalyst to produce a first transalkylation effluent stream comprising cresols, phenol, and alkylbenzenes; introducing the first transalkylation effluent stream into the dealkylation separation zone; and recovering the phenol stream.
[0023] In some embodiments, separating the first dealkylation effluent stream in the dealkylation separation zone includes separating the first dealkylation effluent stream into a phenol stream, a bottoms stream, and at least one of the following streams: a cresol stream comprising cresols, a light hydrocarbon stream comprising light hydrocarbons, and an alkylbenzene stream comprising alkylbenzenes.
[0024] In some embodiments, the method further comprises: separating the cresol stream into a mixed cresol stream comprising p-cresol and o-cresol and a m-cresol stream comprising m-cresol in a cresol separation zone; isomerizing the mixed cresol stream under cresol isomerization reaction conditions in the presence of a cresol isomerization catalyst in a cresol isomerization reaction zone to form a cresol isomerization effluent stream comprising a cresol mixture; recycling the cresol isomerization effluent stream to the cresol separation zone; and recovering the m-cresol stream comprising m-cresol.
[0025] In some embodiments, the method further comprises: separating the alkylbenzene stream into at least a recycle stream comprising one or more of benzene and toluene, a heavy alkylbenzene stream comprising alkylbenzenes having alkyl chains of two or more carbon atoms, and a mixed xylene stream comprising a mixture of xylenes and ethylbenzene in an alkylbenzene separation zone; and recycling the recycle stream from the alkylbenzene separation zone to the first transalkylation reaction zone.
[0026] In some embodiments, the method further includes: separating the mixed xylene stream into a second xylene stream comprising ethylbenzene, o-xylene, and m-xylene and a p-xylene stream comprising p-xylene in a xylene separation zone; isomerizing the second xylene stream under xylene isomerization reaction conditions in the presence of a xylene isomerization catalyst in a xylene isomerization reaction zone to form a xylene isomerization effluent stream comprising a xylene mixture; recycling the xylene isomerization effluent stream to the xylene separation zone; and recovering the p-xylene stream.
[0027] In some embodiments, the method further comprises: dealkylating the heavy alkylbenzene stream in a second dealkylation reaction zone comprising a second dealkylation reactor under second dealkylation conditions in the presence of a second dealkylation catalyst to form a dealkylated heavy alkylbenzene effluent stream comprising xylenes, and benzene or toluene, or both; or transalkylating the heavy alkylbenzene stream in a second transalkylation reaction zone comprising a second transalkylation reactor under second transalkylation conditions in the presence of a second transalkylation catalyst to form a transalkylated heavy alkylbenzene effluent stream comprising xylenes, and benzene or toluene, or both; and optionally recycling the dealkylated heavy alkylbenzene effluent stream, the transalkylated heavy alkylbenzene effluent stream, or both to the alkylbenzene separation zone.
[0028] In some embodiments, the bottoms stream from the dealkylation separation zone further comprises toluene or xylenols, or both.
[0029] In some embodiments, providing an alkylphenol stream comprises: providing a coal-derived feed stream to a first separation zone; and separating the coal-derived feed stream into an alkylphenol stream and at least one of: a first phenol stream comprising phenol and a first cresol stream comprising cresols in the first separation zone.
[0030] In some embodiments, separating the coal-derived feed stream includes separating the coal-derived feed stream by one or more of extraction, absorption, extractive distillation, crystallization, or membrane separation.
[0031] In some embodiments, the coal-derived feed stream comprises a portion of a low temperature coal tar stream, a medium temperature coal tar stream, a high temperature coal tar stream, a cresol acid stream, or a crude phenol mixture.
[0032] In some embodiments, providing the alkylphenol stream includes: providing a coal-derived feed stream to a first separation zone; and separating the coal-derived feed stream into a phenol, cresol, and other alkylphenol streams.
[0033] In some embodiments, the first dealkylation reaction conditions include one or more of the following: temperature range of 50°C to 700°C; pressure range of 0 MPa(g) to 5 MPa(g); WHSV range of 0.1 to 300 hr -1 .
[0034] In some embodiments, the first transalkylation reaction conditions include one or more of the following: a temperature range of 50°C to 600°C; a pressure range of 0 MPa(g) to 15 MPa(g); a WHSV range of 0.1 to 300 hr -1 .
[0035] In some embodiments, dealkylation of the alkylphenol stream and the reactant stream is carried out in a dealkylation reaction zone in the presence of steam, nitrogen, or a combination thereof.
[0036] In some embodiments, transalkylation of the bottoms stream and the reactant stream is performed in the first transalkylation reaction zone in the presence of hydrogen, nitrogen, steam, or a combination thereof.
[0037] In some embodiments, the dealkylation catalyst comprises a heterogeneous acid catalyst, or wherein the first transalkylation catalyst comprises a heterogeneous acid catalyst, or both.
[0038] In some embodiments, at least one of the first dealkylation reaction zone and the first transalkylation reaction zone comprises a fixed bed reactor, a moving bed reactor, an ebullating bed reactor, a fluidized bed reactor, a continuous catalyst regeneration (CCR) reactor, a semi-regenerative reactor, a batch reactor, a continuous stirred tank (CSTR) reactor, a slurry reactor, or a combination thereof.
[0039] Another aspect of the invention is a process for producing phenol from a coal derived feed. In one embodiment, the method includes: providing an alkylphenol stream comprising an alkylphenol having an alkyl chain of two or more carbon atoms; dealkylating the alkylphenol stream in a first dealkylation reaction zone including a first dealkylation reactor under first dealkylation reaction conditions in the presence of a first dealkylation catalyst to produce a first dealkylation effluent stream comprising light hydrocarbons, alkylbenzenes, phenol, cresols and unconverted alkylphenols; separating the first dealkylation effluent stream into at least a phenol stream comprising phenol, a bottoms stream comprising unconverted alkylphenols, and at least one of the following streams: a cresol stream comprising cresols, a light hydrocarbon stream comprising light hydrocarbons, and an alkylbenzene stream comprising alkylbenzenes in a dealkylation separation zone; transalkylating the bottoms stream and a reaction stream comprising toluene or benzene or both in a first transalkylation reaction zone including a first transalkylation reactor under first transalkylation reaction conditions in the presence of a first transalkylation catalyst to produce a first transalkylation effluent stream comprising cresols, phenol and alkylbenzenes; introducing the first transalkylation effluent stream into the dealkylation separation zone; and recovering the phenol stream.
[0040] In some embodiments, the method further comprises: separating the cresol stream from the dealkylation separation zone into a mixed cresol stream comprising p-cresol and o-cresol, and a m-cresol stream comprising m-cresol in a cresol separation zone; isomerizing the mixed cresol stream in a cresol isomerization reaction zone in the presence of a cresol isomerization catalyst under cresol isomerization reaction conditions to form a cresol isomerization effluent stream comprising a cresol mixture; recycling the cresol isomerization effluent stream to the cresol separation zone; recovering the m-cresol stream comprising m-cresol; separating the alkylbenzene stream from the dealkylation separation zone into at least a recycle stream comprising one or more of benzene and toluene, a heavy alkylbenzene stream comprising alkylbenzenes having alkyl chains of 2 or more carbon atoms, and a mixed xylene stream comprising a mixture of xylenes and ethylbenzene in an alkylbenzene separation zone; recycling the recycle stream from the alkylbenzene separation zone to the first transalkylation reaction zone; separating the mixed xylene stream into a second xylene stream comprising ethylbenzene, o-xylene and m-xylene in a xylene separation zone; isomerizing a second xylene stream in a xylene isomerization reaction zone in the presence of a xylene isomerization catalyst under xylene isomerization reaction conditions to form a xylene isomerization effluent stream comprising a xylene mixture; recycling the xylene isomerization effluent stream to the xylene separation zone; and recovering the p-xylene stream; dealkylating a heavy alkylbenzene stream in a second dealkylation reaction zone including a second dealkylation reactor in the presence of a second dealkylation catalyst under second dealkylation conditions to form a dealkylated heavy alkylbenzene effluent stream comprising xylenes, and benzene or toluene, or both; or transalkylating a heavy alkylbenzene stream in a second transalkylation reaction zone in the presence of a second transalkylation catalyst under second transalkylation conditions to form a transalkylated heavy alkylbenzene effluent stream comprising xylenes, and benzene or toluene, or both; and recycling the dealkylated heavy alkylbenzene effluent stream, the transalkylated heavy alkylbenzene effluent stream, or both to the alkylbenzene separation zone.
[0041] In some embodiments, providing an alkylphenol stream comprises: providing a coal-derived feed stream to a first separation zone; and separating the coal-derived feed stream into an alkylphenol stream and at least one of: a first phenol stream comprising phenol and a first cresol stream comprising cresols in the first separation zone.
[0042] In some embodiments, the first dealkylation reaction conditions include one or more of the following: temperature range of 50°C to 700°C; pressure range of 0 MPa(g) to 5 MPa(g); WHSV range of 0.1 to 300 hr -1; or wherein the first transalkylation reaction conditions include one or more of the following: a temperature range of 50°C to 600°C; a pressure range of 0MPa(g) to 15MPa(g); a WHSV range of 0.1 to 300hr -1 ; or both.
[0043] Figure 1 A schematic flow diagram of one embodiment of the integrated process 100 is shown. A feed stream 105 comprising an acid fraction and crude phenol from coal-derived liquids is sent to a first separation zone 110 where it is separated into a phenol stream 115 comprising phenol, a cresol stream 120 comprising cresols, and an alkylphenol stream 125 comprising alkylphenols having an alkyl chain of two or more carbon atoms. Suitable first separation methods include, but are not limited to, distillation, extraction, adsorption, extractive distillation, crystallization, membrane separation, or a combination thereof.
[0044] The alkylphenol stream 125 is passed to a first dealkylation reaction zone 130 which includes one or more dealkylation reactors with a dealkylation catalyst.
[0045] Dealkylation can be carried out with or without a catalyst. Alkylphenols can be dealkylated without a catalyst by high temperature thermal cracking. Dealkylation without a catalyst can be very energy intensive because the temperatures are 400 to 900 °C, typically 700 to 900 °C. In addition, dealkylation is generally not selective due to the loss of hydroxyl groups.
[0046] Catalytic dealkylation of heavy alkylphenols can be carried out under milder conditions. Typical temperatures range from 100 to 700°C or 200 to 540°C. Ethylphenol and propylphenol can be dealkylated at temperatures of 300 to 400°C, for example, to produce phenol and ethylene / propylene over ZSM-5 zeolite. Debutylation of alkylphenols over acidic clay catalysts has also been reported. Any suitable dealkylation catalyst can be used, including but not limited to silica alumina, acidic clays, zeolites, gamma alumina, chromium oxide, other metal oxides or mixed metal oxides, or combinations thereof.
[0047] The pressure of dealkylation is usually 1-5 MPa(a). The dealkylation reaction can also be carried out under vacuum, for example, usually 50 kPa(a) and a maximum of 20 kPa(a). The weight hourly space velocity (WHSV) is usually 1 to 5 hr -1 .
[0048] Water / steam may be fed simultaneously to prevent severe catalyst deactivation. Dealkylation is usually carried out in superheated steam. Typical steam to alkylphenol weight ratios are 0.1:1 to 10:1, or 0.5:1 to 5:1.
[0049] The first dealkylation effluent stream 135 comprises light hydrocarbons (C1-C7 hydrocarbons, such as ethylene, propylene, etc.), alkylbenzenes, phenol, cresols, and unconverted alkylphenols.
[0050] The first dealkylation effluent stream 135 is separated in the dealkylation separation zone 140 into at least a phenol stream 145 comprising phenol and a bottoms stream 150 comprising unconverted alkylphenol. The first dealkylation effluent stream 135 may optionally be separated into one or more additional streams, such as a light hydrocarbon stream 155 comprising light hydrocarbons, an alkylbenzene stream 160 comprising alkylbenzenes, a cresol stream 165 comprising cresols, and a process water stream 170 comprising water. Suitable dealkylation separation methods include, but are not limited to, distillation, extractive distillation, adsorption, crystallization, membrane separation, or combinations thereof.
[0051] A phenol stream 145 from the first dealkylation separation zone 140 may be recovered.
[0052] The bottoms stream 150 is sent to a first transalkylation reaction zone 175 where it is transalkylated with a reactant feed stream comprising benzene and / or toluene 180. The first transalkylation reaction zone 175 comprises one or more transalkylation reactors.
[0053] When a catalyst is used to carry out the transalkylation of alkylphenols, the temperature is generally 50-600°C or 100-500°C. The transalkylation zone is generally operated at a pressure range of about 0 MPa(g) to 15 MPa(g) or 2 MPa(g) to 11 MPa(g). The weight hourly space velocity (WHSV) is generally 0.1 to 300 hr -1 or 1 to 250hr -1 .
[0054] Catalysts are generally selected that have relatively high stability at high activity levels. Suitable transalkylation catalysts include, but are not limited to, zeolites, acidic clays, silica aluminas, acidic resins, mixed metal oxides, and the like as known in the art.
[0055] The ratio (molar ratio) of benzene / toluene to phenol is 0.1:1 to 20:1, or 0.5:1 to 10:1, or 1:1 to 5:
[0056] The first transalkylation effluent stream 185 comprising cresols, phenol, and alkylbenzenes is sent to the dealkylation separation zone 140 for separation.
[0057] The alkylbenzene stream 160 may be sent to an alkylbenzene separation zone 190 where it is separated into at least a recycle stream 195 comprising one or more of benzene and toluene, a heavy alkylbenzene stream 200 comprising alkylbenzenes having alkyl chains of two or more carbon atoms, and a mixed xylene stream 205 comprising a mixture of xylenes and ethylbenzene. Suitable alkylbenzene separation methods include, but are not limited to, distillation, extractive distillation, or a combination thereof.
[0058] The recycle stream 195 may be sent to the first transalkylation reaction zone 175 .
[0059] The heavy alkylbenzene stream 200 may be sent to a second dealkylation reaction zone or a second transalkylation reaction zone 210, or both, where the heavy alkylbenzene stream 200 is dealkylated or transalkylated.
[0060] The heavy alkylbenzene dealkylation reaction conditions include a temperature of typically 0°C to 600°C or 100°C to 500°C. The heavy alkylbenzene dealkylation zone is typically operated at a pressure range of about 0 MPa(g) to 7.6 MPa(g) or 0.01 MPa(g) to 5 MPa(g). The WHSV is typically 0.01 to 200 hr -1 or 0.1 to 100hr -1 Any suitable heavy alkylbenzene dealkylation catalyst may be used. Catalysts having relatively high stability at high activity levels are generally selected. Suitable heavy alkylbenzene dealkylation catalysts include, but are not limited to, zeolites, acidic clays, silica alumina, acidic resins, mixed metal oxides, and the like known in the art.
[0061] The heavy alkylbenzene transalkylation reaction conditions include a temperature of typically 0°C to 600°C or 100°C to 500°C. The heavy alkylbenzene transalkylation is typically operated in a pressure range of about 0 MPa(g) to 15 MPa(g) or 1 MPa(g) to 11 MPa(g). The WHSV is typically 0.1 to 300 hr -1 or 0.2 to 200hr -1 Any suitable heavy alkylbenzene transalkylation catalyst may be used. Catalysts having relatively high stability at high activity levels are generally selected. Suitable heavy alkylbenzene transalkylation catalysts include, but are not limited to, zeolites, acidic clays, silica alumina, acidic resins, mixed metal oxides, and the like known in the art.
[0062] The dealkylation effluent stream 215 comprises one or more of benzene, toluene, and xylenes, and / or the transalkylation effluent stream 215 comprises one or more of benzene, toluene, and xylenes.
[0063] Mixed xylene stream 205 may be sent to xylene separation zone 220 where it is separated into a para-xylene stream 225 comprising para-xylene and a second mixed xylene stream 230 comprising ethylbenzene, ortho-xylene, and meta-xylene. Para-xylene stream 225 may be recovered.
[0064] Any suitable xylene separation method may be used, including but not limited to distillation, adsorption (e.g., UOP's Parex TM method), crystallization (e.g., the pX method of BP / CBI), or a combination of these methods.
[0065] The second mixed xylene stream 230 is sent to a xylene isomerization zone 240 for isomerization of ortho-xylene and meta-xylene. A xylene isomerization effluent stream 245 comprising a xylene mixture is sent to the xylene separation zone 220. The xylene isomerization zone 240 includes one or more xylene isomerization reactors.
[0066] Suitable xylene isomerization processes include, but are not limited to, UOP's Isomar TM method.
[0067] The xylene isomerization reaction zone 240 is typically operated at a reaction condition of 50°C to 600°C or 100°C to 500°C. The xylene isomerization zone is typically operated at a moderately elevated pressure, which generally ranges from 0 MPa to 7.6 MPa gauge pressure or 0.01 MPa to 5 MPa gauge pressure. The xylene isomerization reaction can be carried out over a wide range of liquid hourly space velocities (LHSV). The LHSV is typically 0.1 to 5 hr -1 or 0.2 to 4 hours -1 In some embodiments, the xylene isomerization reaction is carried out under the following reaction conditions: temperature range is 50°C to 600°C, pressure range is 0 MPa(g) to 7.6 MPa(g); LHSV range is 0.1 to 5 hr -1 In some embodiments, the xylene isomerization reaction is carried out under the following reaction conditions: temperature range is 100°C to 500°C, pressure range is 0.01 MPa(g) to 5 MPa(g); LHSV range is 0.2 to 4 hr -1 .
[0068] Any suitable xylene isomerization catalyst can be used. Suitable xylene isomerization catalysts include, but are not limited to, homogeneous catalysts (e.g., BF3-HF) and heterogeneous catalysts (e.g., amorphous silica alumina, zeolite, or metal-promoted zeolite). Catalysts with relatively high stability at high activity levels are generally selected.
[0069] Cresol stream 165 may be sent to cresol separation zone 250 where it is separated into a mixed cresol stream 255 comprising p-cresol and o-cresol and a m-cresol stream 260 comprising m-cresol. Cresol stream 120 may also be sent to cresol separation zone 250. m-cresol stream 260 may be recovered.
[0070] Suitable cresol separation methods include, but are not limited to, distillation, crystallization, adsorption (e.g., UOP's Cresex TM adsorption method) or a combination thereof.
[0071] The mixed cresol stream 255 is sent to the cresol isomerization zone 265 for isomerization of p-cresol and o-cresol. The cresol isomerization effluent stream 270 comprising the cresol mixture is sent to the cresol separation zone 250.
[0072] Cresol isomerization reaction conditions typically include temperatures of 50°C to 600°C or 100°C to 500°C. The cresol isomerization zone typically operates at a pressure in the range of about 0 MPa(g) to 15 MPa(g) or 0.01 MPa(g) to 10 MPa(g). The WHSV is typically 0.1 to 200 hr -1 or 0.2 to 100hr -1 .
[0073] Any suitable cresol isomerization catalyst can be used. A cresol isomerization catalyst having relatively high stability at a high activity level is generally selected. Suitable cresol isomerization catalysts include, but are not limited to, zeolites, acidic clays, silica alumina, acidic resins, mixed metal oxides, etc. known in the art.
[0074] Figure 2 Another embodiment of the integrated method 300 is shown. The method 300 is similar to Figure 1 The process 100 shown in FIG. 1 is different in that the feed stream 105 is separated into a phenol stream 115, a cresol stream 120, an alkylphenol stream 125, and a xylenol stream 305 comprising xylenols and trimethylphenols in the first separation zone 110. The xylenol stream 305 can be sent to the first transalkylation reaction zone 175 together with the bottom stream 150 from the dealkylation separation zone 140, the reactant feed stream 180, and the recycle stream 195 from the alkylbenzene separation zone 190. The xylenols are converted into phenol and cresols in the first transalkylation reaction zone 175.
[0075] Figure 2 The method of directly co-feeding the xylenol stream from the first separation zone 110 to the first transalkylation reaction zone 175 can reduce the equipment size of the dealkylation process. It also provides greater flexibility for plant operation to meet market demand for xylenol products. Example
[0076] The predicted product yields for toluene transalkylation and dealkylation following computer simulations using Honeywell UniSim Design software are summarized in Table 1. The calculations assume an overall conversion of 98% for dealkylation and a toluene recycle of 95% for transalkylation.
[0077] The product profile of the dealkylation is based only on alkylphenols, with no xylenols present in the feed.
[0078] Table 1: Product profiles of proposed dealkylation of alkylphenols and transalkylation of toluene
[0079]
[0080] The predicted product profiles of the proposed integrated process are compared with toluene transalkylation alone using Honeywell UniSim Design in Table 2. The integrated process increases the phenol yield by up to about 26% by weight. The phenol yield of the integrated case (Case 1) is increased by about 100% compared to the toluene transalkylation case (Case 0). The phenol yield is maximized when all the xylenols from the first separation zone are considered as products and do not participate in the transalkylation with toluene. The yield of alkylbenzenes is reduced from 56.5% by weight in Case 0 to 15% by weight in Case 2. Therefore, in Case 2, phenol rather than alkylbenzenes becomes the main product, which is desirable for a phenol plant.
[0081] Table 2: Product profile of the integrated process for dealkylation and transalkylation of alkylphenol toluene
[0082]
[0083] As used herein, the term "zone" may refer to an area that includes one or more equipment items and / or one or more sub-areas. Equipment items may include one or more reactors or reactor vessels, heaters, exchangers, pipes, pumps, compressors, and controllers. In addition, equipment items such as reactors, dryers, or containers may also include one or more zones or sub-areas.
[0084] As used herein, the term "about" means within 10%, or within 5%, or within 1% of the value.
[0085] As shown, the process flow lines in the figures may be referred to interchangeably as, for example, lines, conduits, branches, distributors, streams, effluents, feeds, products, portions, catalysts, withdrawals, recycles, pumps, discharges, and bases.
[0086] Although at least one exemplary embodiment is proposed in the above detailed description of the present invention, it should be recognized that there are a large number of variations. It should also be recognized that one or more exemplary embodiments are merely examples and are not intended to limit the scope, applicability or configuration of the present invention in any way. On the contrary, the above detailed description will provide a convenient roadmap for implementing the exemplary embodiments of the present invention to those skilled in the art. It should be understood that various changes may be made to the functions and arrangements of the elements described in the exemplary embodiments without departing from the scope of the present invention described in the appended claims.
Claims
1. A method for producing phenol from a coal-derived feed, comprising: providing an alkylphenol stream comprising alkylphenols having an alkyl chain of two or more carbon atoms; dealkylating an alkylphenol stream in a first dealkylation reaction zone comprising a first dealkylation reactor in the presence of a first dealkylation catalyst and under first dealkylation reaction conditions to produce a first dealkylation effluent stream comprising light hydrocarbons, alkylbenzenes, phenol, cresols, and unconverted alkylphenol; separating the first dealkylation effluent stream into at least a phenol stream comprising phenol and a bottoms stream comprising unconverted alkylphenol in a dealkylation separation zone; transalkylating a bottoms stream and a reactant stream comprising toluene or benzene or both in a first transalkylation reaction zone comprising a first transalkylation reactor in the presence of a first transalkylation catalyst and under first transalkylation reaction conditions to produce a first transalkylation effluent stream comprising cresols, phenol, and alkylbenzenes; introducing a first transalkylation effluent stream into a dealkylation separation zone; and A phenol stream is recovered.
2. The method of claim 1 , wherein separating the first dealkylation effluent stream in the dealkylation separation zone comprises separating the first dealkylation effluent stream into a phenol stream, a bottoms stream, and at least one of the following streams: a cresol stream comprising cresols, a light hydrocarbon stream comprising light hydrocarbons, and an alkylbenzene stream comprising alkylbenzenes.
3. The method according to claim 2, further comprising: separating the cresol stream into a mixed cresol stream comprising p-cresol and o-cresol and a m-cresol stream comprising m-cresol in a cresol separation zone; isomerizing the mixed cresols stream in a cresol isomerization reaction zone in the presence of a cresol isomerization catalyst under cresol isomerization reaction conditions to form a cresol isomerization effluent stream comprising a mixture of cresols; recycling the cresol isomerization effluent stream to the cresol separation zone; as well as A m-cresol stream comprising m-cresol is recovered.
4. The method according to claim 2, further comprising: separating the alkylbenzene stream in an alkylbenzene separation zone into at least a recycle stream comprising one or more of benzene and toluene, a heavy alkylbenzene stream comprising alkylbenzenes having alkyl chains of two or more carbon atoms, and a mixed xylene stream comprising a mixture of xylenes and ethylbenzene; as well as The recycle stream from the alkylbenzene separation zone is recycled to the first transalkylation reaction zone.
5. The method according to claim 4, further comprising: separating the mixed xylene stream into a second xylene stream comprising ethylbenzene, ortho-xylene, and meta-xylene, and a para-xylene stream comprising para-xylene in a xylene separation zone; isomerizing the second xylene stream in a xylene isomerization reaction zone in the presence of a xylene isomerization catalyst under xylene isomerization reaction conditions to form a xylene isomerization effluent stream comprising a xylene mixture; recycling a xylene isomerization effluent stream to a xylene separation zone; as well as A paraxylene stream is recovered.
6. The method according to claim 5, further comprising: Dealkylating a heavy alkylbenzene stream in a second dealkylation reaction zone comprising a second dealkylation reactor in the presence of a second dealkylation catalyst under second dealkylation conditions to form a dealkylated heavy alkylbenzene effluent stream comprising xylenes, and benzene or toluene, or both; or transalkylating a heavy alkylbenzene stream in a second transalkylation reaction zone comprising a second transalkylation reactor in the presence of a second transalkylation catalyst under second transalkylation conditions to form a transalkylated heavy alkylbenzene effluent stream comprising xylenes, and benzene or toluene, or both; as well as Optionally, the dealkylation heavy alkylbenzene effluent stream, the transalkylation heavy alkylbenzene effluent stream, or both are recycled to the alkylbenzene separation zone.
7. A process according to any one of claims 1 to 6, wherein the bottoms stream from the dealkylation separation zone further comprises toluene or xylenols or both.
8. The method of any one of claims 1 to 7, wherein providing an alkylphenol stream comprises: providing a coal-derived feed stream to a first separation zone; as well as The coal-derived feed stream is separated in a first separation zone into an alkylphenol stream and at least one of: a first phenol stream comprising phenol and a first cresol stream comprising cresols.
9. The method of claim 8, wherein separating the coal-derived feed stream comprises separating the coal-derived feed stream by one or more of extraction, absorption, extractive distillation, crystallization, or membrane separation.
10. The method of claim 8, wherein the coal-derived feed stream comprises a portion of a low temperature coal tar stream, a medium temperature coal tar stream, a high temperature coal tar stream, a cresol acid stream, or a crude phenol mixture.
11. The method according to any one of claims 1 to 10, wherein the first dealkylation reaction conditions include one or more of the following: a temperature range of 50°C to 700°C; a pressure range of 0 MPa(g) to 5 MPa(g); a WHSV range of 0.1 to 300 hr -1 .
12. The method according to any one of claims 1 to 11, wherein the first transalkylation reaction conditions include one or more of the following: a temperature range of 50°C to 600°C; a pressure range of 0 MPa(g) to 15 MPa(g); a WHSV range of 0.1 to 300 hr -1 .
13. The process of any one of claims 1 to 12, wherein the dealkylation of the alkylphenol stream and the reactant stream is carried out in the dealkylation reaction zone in the presence of steam, nitrogen or a combination thereof.
14. The process of any one of claims 1 to 13, wherein the transalkylation of the bottoms stream and the reactant stream is carried out in the first transalkylation reaction zone in the presence of hydrogen, nitrogen, steam or a combination thereof.
15. The process of any one of claims 1-14, wherein the dealkylation catalyst comprises a heterogeneous acid catalyst, or wherein the first transalkylation catalyst comprises a heterogeneous acid catalyst, or both.
16. The process of any one of claims 1 to 15, wherein at least one of the first dealkylation reaction zone and the first transalkylation reaction zone comprises a fixed bed reactor, a moving bed reactor, an ebullated bed reactor, a fluidized bed reactor, a continuous catalyst regeneration (CCR) reactor, a semi-regenerative reactor, a batch reactor, a continuous stirred tank (CSTR) reactor, a slurry reactor, or a combination thereof.
17. A method for producing phenol from a coal derived feed comprising: providing an alkylphenol stream comprising alkylphenols having an alkyl chain of two or more carbon atoms; dealkylating an alkylphenol stream in a first dealkylation reaction zone comprising a first dealkylation zone in the presence of a first dealkylation catalyst and under first dealkylation reaction conditions to produce a first dealkylation effluent stream comprising light hydrocarbons, alkylbenzenes, phenol, cresols, and unconverted alkylphenol; separating the first dealkylation effluent stream in a dealkylation separation zone into at least a phenol stream comprising phenol, a bottoms stream comprising unconverted alkylphenol, and at least one of: a cresol stream comprising cresols, a light hydrocarbon stream comprising light hydrocarbons, and an alkylbenzene stream comprising alkylbenzenes; transalkylating a bottoms stream and a reactant stream comprising toluene or benzene or both in a first transalkylation reaction zone comprising a first transalkylation reactor in the presence of a first transalkylation catalyst and under first transalkylation reaction conditions to produce a first transalkylation effluent stream comprising cresols, phenol, and alkylbenzenes; introducing a first transalkylation effluent stream into a dealkylation separation zone; as well as Recovering phenol streams; The coal-derived feed stream comprises a portion of a low-temperature coal tar stream, a medium-temperature coal tar stream, a high-temperature coal tar stream, a cresol acid stream or a crude phenol mixture.
18. The method according to claim 17, further comprising: separating the cresol stream from the dealkylation separation zone into a mixed cresol stream comprising p-cresol and o-cresol and a m-cresol stream comprising m-cresol in a cresol separation zone; isomerizing the mixed cresols stream in a cresol isomerization reaction zone in the presence of a cresol isomerization catalyst under cresol isomerization reaction conditions to form a cresol isomerization effluent stream comprising a mixture of cresols; recycling the cresol isomerization effluent stream to the cresol separation zone; recovering a m-cresol stream comprising m-cresol; separating in an alkylbenzene separation zone an alkylbenzene stream from the dealkylation separation zone into at least a recycle stream comprising one or more of benzene and toluene, a heavy alkylbenzene stream comprising alkylbenzenes having alkyl chains of 2 or more carbon atoms, and a mixed xylene stream comprising a mixture of xylenes and ethylbenzene; recycling a recycle stream from the alkylbenzene separation zone to the first transalkylation reaction zone; separating the mixed xylene stream into a second xylene stream comprising ethylbenzene, ortho-xylene, and meta-xylene and a para-xylene stream comprising para-xylene in a xylene separation zone; isomerizing the second xylene stream in a xylene isomerization reaction zone in the presence of a xylene isomerization catalyst under xylene isomerization reaction conditions to form a xylene isomerization effluent stream comprising a xylene mixture; recycling a xylene isomerization effluent stream to a xylene separation zone; Recovering paraxylene logistics; dealkylating a heavy alkylbenzene stream in a second dealkylation reaction zone comprising a second dealkylation reactor in the presence of a second dealkylation catalyst and under second dealkylation conditions to form a dealkylated heavy alkylbenzene effluent stream comprising xylenes, and benzene or toluene or both; or transalkylating the heavy alkylbenzene stream in a second transalkylation reaction zone comprising a second transalkylation reactor in the presence of a second transalkylation catalyst and under second transalkylation conditions to form a transalkylated heavy alkylbenzene effluent stream comprising xylenes, and benzene or toluene or both; and The dealkylated heavy alkylbenzene effluent stream, the transalkylated heavy alkylbenzene effluent stream, or both are recycled to the alkylbenzene separation zone.
19. The method of any one of claims 17-18, wherein providing an alkylphenol stream comprises: providing a coal-derived feed stream to a first separation zone; as well as The coal-derived feed stream is separated in a first separation zone into an alkylphenol stream and at least one of: a first phenol stream comprising phenol and a first cresol stream comprising cresols.
20. The method according to any one of claims 17 to 19: in, The first dealkylation reaction conditions include one or more of the following: a temperature range of 50°C to 700°C; a pressure range of 0 MPa(g) to 5 MPa(g); a WHSV range of 0.1 to 300 hr -1 ;or The first transalkylation reaction conditions include one or more of the following: temperature range of 50°C to 600°C; pressure range of 0MPa(g) to 15MPa(g); WHSV range of 0.1 to 300hr -1 ;or both.