A synthetic thermally conductive medium and its synthesis method and system

Abstract

This invention provides a synthetic thermally conductive medium, its synthesis method, and system. The synthetic thermally conductive medium, by weight, contains 65-88% dicyclohexylbenzene, 10-25% cyclohexylbiphenyl, and 2-10% other C4 compounds. 18 The above-mentioned components have a maximum operating temperature exceeding 330℃. This invention uses benzene and hydrogen as raw materials to produce synthetic thermal conductive media, avoiding the problem of insufficient terphenyl source in traditional processes, thus significantly increasing the yield of synthetic thermal conductive media. The reaction temperature during production is reduced from over 600℃ in traditional processes to below 250℃, resulting in a significant reduction in energy consumption and lower requirements for equipment materials, thereby reducing production costs. The unsaturation of the synthetic thermal conductive media is adjusted through a partial dehydrogenation reaction, ensuring its quality control.

Description

Technical Field

[0001] This invention relates to a synthetic thermally conductive medium and its synthesis method and system. Background Technology

[0002] Currently, thermal conductive media on the market are mainly divided into mineral-based thermal conductive media and synthetic thermal conductive media. Compared with mineral-based thermal conductive media, synthetic thermal conductive media have advantages such as better high-temperature stability, less high-temperature cracking, longer lifespan, and renewability, thus having a broader application prospect.

[0003] In recent years, with the rapid development of solar thermal new energy, synthetic fibers and other fields, the demand for high-temperature synthetic thermal conductivity media, represented by hydrogenated terphenyl, has been increasing year by year. CN103804114B discloses a method for preparing hydrogenated terphenyl, which involves passing benzene vapor and a catalyst into an infrared-heated tubular reactor to react and generate biphenyl and terphenyl. After two distillations, relatively pure terphenyl is obtained, and finally, hydrogenation is carried out in a high-pressure hydrogenation reactor to obtain hydrogenated terphenyl. This method can reduce some energy consumption by using infrared heating, but it still suffers from problems such as low yield of hydrogenated terphenyl, high reaction temperature (above 500℃), and a large number of by-products in the hydrogenation process.

[0004] CN107032942A discloses a method for producing heat transfer oil from the organic solid residue of distillation during the production of biphenyl alcohol. This method involves using the organic solid residue generated from the intermediate coupling compound 2-methyl-3-chlorobiphenyl in the preparation of biphenyl alcohol to produce hydrogenated terphenyl, a high-temperature heat transfer medium, through a suitable chemical reaction. However, this method suffers from problems such as complex processes, low catalyst activity and short catalyst life, high manufacturing costs, and difficulty in industrialization. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the problems of limited raw material sources, low yield, high energy consumption and complex processes in the previous technology, and to provide a new method for producing synthetic high-temperature thermal conductive media. This method has the advantages of wide availability of raw materials, high yield, low energy consumption and simple process flow.

[0006] According to a first aspect of the present invention, a synthetic thermally conductive medium is provided, wherein, based on the total weight of the synthetic thermally conductive medium, the synthetic thermally conductive medium contains 65-88% dicyclohexylbenzene, 10-25% cyclohexylbiphenyl, and 2-10% other C4 compounds. 18 The above-mentioned recombinant components have a maximum operating temperature of over 330℃.

[0007] According to a second aspect of the present invention, the present invention provides a method for synthesizing a thermally conductive medium, the method comprising:

[0008] a) Benzene and hydrogen are fed into a hydroalkylation reactor to react and produce dicyclohexylbenzene, cyclohexylbiphenyl, cyclohexylbenzene, cyclohexane, and C64. 18 The reaction products of the above components;

[0009] b) The reaction product is fed into a C6 removal tower, and light components and C6 components are separated from the top of the C6 removal tower. A portion of the C6 components is sent back to the inlet of the hydroalkylation reactor to be mixed with the feed benzene, and the bottom material of the C6 removal tower is obtained at the bottom of the tower.

[0010] c) Feed part or all of the bottom material from the C6 removal tower into the dehydrogenation reactor for dehydrogenation to obtain an incremental dehydrogenation product of cyclohexylbiphenyl.

[0011] d) The dehydrogenation product and, optionally, the remaining bottoms from the C6 dehydrogenation column are fed into a separation column to separate C6-rich cyclohexylbenzene from the top of the separation column. 12 The stream, from the bottom of the separation tower, separates a thermally conductive medium, preferably by weight of the total thermally conductive medium, which contains 65-88% dicyclohexylbenzene, 10-25% cyclohexylbiphenyl, and 2-10% other C4 compounds. 18 The above-mentioned recombinant components have a maximum operating temperature of over 330℃;

[0012] Preferably, the operating temperature of the synthesized thermally conductive medium is 330-380℃; and / or

[0013] More preferably, the other C 18 The above-mentioned recombinant components contain tricyclohexylbenzene and / or dicyclohexylbiphenyl.

[0014] According to a third aspect of the present invention, the present invention provides a system for use in the method for synthesizing the thermally conductive medium described herein, the system comprising: a hydroalkylation reactor, a C6 removal tower, a dehydrogenation reactor, and a separation tower connected in series along the feed flow direction, wherein the material outlet of the hydroalkylation reactor is connected to the inlet of the C6 removal tower, the material outlet of the C6 removal tower is connected to the inlet of the dehydrogenation reactor, the outlet of the dehydrogenation reactor is connected to the inlet of the separation tower, and the top material outlet of the separation tower is connected to the inlet of the hydroalkylation reactor.

[0015] Compared with existing technologies, the present invention has the following outstanding advantages:

[0016] 1) Using benzene and hydrogen as raw materials to produce synthetic thermal conductive media avoids the problem of insufficient terphenyl source in traditional processes, which can greatly increase the output of synthetic thermal conductive media.

[0017] 2) The reaction temperature during the production process has been reduced from over 600℃ in the traditional process to below 250℃, which greatly reduces energy consumption and also reduces the requirements for equipment materials, thus reducing production costs.

[0018] 3) Adjust the unsaturation of the synthesized thermal conductive medium by dehydrogenating some of the reaction products to ensure its quality control.

[0019] This invention primarily addresses the problems of high energy consumption, numerous byproducts, and complex processes inherent in traditional methods for producing synthetic thermal conductive media. This invention produces synthetic thermal conductive media using benzene and hydrogen as raw materials. According to the method of this invention, in a preferred embodiment, the raw material benzene is reacted with C2000, a cyclohexylbenzene-rich gas recycled from the top of the product separation tower. 12 After mixing, the raw materials are mixed with hydrogen and then fed into a hydroalkylation reactor to produce dicyclohexylbenzene, cyclohexylbiphenyl, benzene, cyclohexane, etc. The reaction products are then fed into a C6 removal tower to separate the light and C6 components. The bottom material from the C6 removal tower is then fed into a dehydrogenation reactor for partial dehydrogenation, producing a dehydrogenated product containing more cyclohexylbiphenyl than the feed. The dehydrogenated product is fed into a product separation tower; the bottom of the tower yields a product synthesis-type thermal conductivity medium, and the top yields a C6-rich product containing cyclohexylbenzene. 12 The material is recycled back to the hydrogenation alkylation reactor. The technical solution of this invention features a simple process, low energy consumption, few byproducts, and controllable unsaturation of the synthetic thermally conductive medium, effectively solving the aforementioned problems and demonstrating significant technical advantages and promising application prospects. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a system for producing synthetic high-temperature thermal conductive media.

[0021] Explanation of reference numerals in the attached figures

[0022] 1-Feed heater for hydroalkylation reactor; 2-Hydroalkylation reactor;

[0023] 3-Dehydrogenation reactor feed heater, 4-Dehydrogenation reactor;

[0024] 5-C6 removal tower, 6-C6 removal tower top condenser;

[0025] 7 - Reflux tank for C6 removal column; 8 - Reboiler for C6 removal column;

[0026] 9 - Discharge pump from C6 separation tower; 10 - Separation tower;

[0027] 11-Separation tower top condenser; 12-Separation tower reflux tank;

[0028] 13-Separation tower reboiler, 14-Product pump, 15-Product cooler;

[0029] CW - Cooling water, HS - High-pressure steam. Detailed Implementation

[0030] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0031] This invention provides a synthetic thermally conductive medium, which, by weight, contains 65-88% dicyclohexylbenzene, 10-25% cyclohexylbiphenyl, and 2-10% other C4 compounds. 18 The above-mentioned recombinant components have a maximum operating temperature of over 330℃.

[0032] According to a preferred embodiment of the present invention, the operating temperature of the synthetic thermally conductive medium is 330-380°C.

[0033] According to a preferred embodiment of the present invention, the other C 18 The above-mentioned recombinant components contain tricyclohexylbenzene and / or dicyclohexylbiphenyl.

[0034] All thermally conductive media possessing the aforementioned properties of this invention can achieve the objectives of this invention, and there are no special requirements for their preparation methods. In relation to this invention, this invention provides a method for synthesizing a thermally conductive medium, the method comprising:

[0035] a) Benzene and hydrogen are fed into a hydroalkylation reactor to react and produce dicyclohexylbenzene, cyclohexylbiphenyl, cyclohexylbenzene, cyclohexane, and C64. 18 The reaction products of the above components;

[0036] b) The reaction product is fed into a C6 removal tower, and light components and C6 components are separated from the top of the C6 removal tower. A portion of the C6 components is sent back to the inlet of the hydroalkylation reactor to be mixed with the feed benzene, and the bottom material of the C6 removal tower is obtained at the bottom of the tower.

[0037] c) Feed part or all of the bottom material from the C6 removal tower into the dehydrogenation reactor for dehydrogenation to obtain an incremental dehydrogenation product of cyclohexylbiphenyl.

[0038] d) The dehydrogenation product and, optionally, the remaining bottoms from the C6 dehydrogenation column are fed into a separation column to separate C6-rich cyclohexylbenzene from the top of the separation column. 12 The stream, from the bottom of the separation tower, separates a thermally conductive medium, preferably by weight of the total thermally conductive medium, which contains 65-88% dicyclohexylbenzene, 10-25% cyclohexylbiphenyl, and 2-10% other C4 compounds. 18 The above-mentioned recombinant components have a maximum operating temperature of over 330℃.

[0039] According to a preferred embodiment of the present invention, the operating temperature of the synthetic thermally conductive medium is 330-380°C.

[0040] According to a preferred embodiment of the present invention, the other C18 The above-mentioned recombinant components contain tricyclohexylbenzene and / or dicyclohexylbiphenyl.

[0041] According to the method of the present invention, in order to better achieve online adjustment of the unsaturation of the synthetic thermal conductivity medium, a portion of the bottom material from the C6 removal tower is optionally fed into a dehydrogenation reactor for a dehydrogenation reaction to obtain the dehydrogenation product. Preferably, the ratio of the portion of the C6 removal tower bottom material entering the dehydrogenation reactor to the total C6 removal tower bottom material is 0.05-1:1, more preferably 0.1-0.5:1. This can lower the freezing point of the product and expand its application range.

[0042] According to the method of the present invention, the method preferably further includes separating the C-rich cyclohexylbenzene-rich C-separated from the top of the separation column. 12 The logistics return is used as feedstock for the hydrogenation alkylation reaction in step a), preferably the benzene feedstock and recycled C40 rich in cyclohexylbenzene. 12 The material quality ratio is 0.1-10.0:1, preferably 0.5-3.0:1. This can reduce raw material consumption and improve raw material utilization efficiency.

[0043] According to a preferred embodiment of the method of the present invention, the method includes:

[0044] a) The feed benzene is mixed with C40, a cyclohexylbenzene-rich recycle from the top of the separator. 12 After the raw materials are mixed, they are then mixed with hydrogen and fed into a hydroalkylation reactor to produce dicyclohexylbenzene, cyclohexylbiphenyl, cyclohexylbenzene, cyclohexane, and C64. 18 The reaction products of the above components;

[0045] b) The reaction product is fed into a C6 removal tower, where light components and C6 components are separated at the top of the C6 removal tower. A portion of the C6 components is sent back to the inlet of the hydroalkylation reactor to be mixed with the feed benzene, and the bottom material of the C6 removal tower is obtained at the bottom of the tower.

[0046] c) Feed part or all of the bottom material from the C6 removal tower into the dehydrogenation reactor to generate an incremental dehydrogenation product of cyclohexylbiphenyl.

[0047] d) The dehydrogenation product and the remaining bottoms from the C6 removal tower are fed into a separation tower, from which C6-rich cyclohexylbenzene is separated from the top of the separation tower. 12 The logistics process involves separating the thermally conductive medium from the bottom of the separation tower, and then transferring the C-rich cyclohexylbenzene-rich C-material obtained from the top of the tower. 12 The feedstock is recycled back to the hydroalkylation reactor. This reduces feedstock consumption and improves feedstock utilization efficiency.

[0048] According to a preferred embodiment of the present invention, the feedstock benzene and C2C4 rich in cyclohexylbenzene from the top recycle of the separation tower are reacted. 12The mixed materials react in a hydrogenation alkylation reactor to produce dicyclohexylbenzene, cyclohexylbiphenyl, cyclohexylbenzene, etc. In addition, side reactions will occur to produce byproducts such as cyclohexane and hydrogenated tetraphenyl.

[0049] To control the properties of the synthetic thermally conductive medium, it is necessary to control its unsaturation. Therefore, the technical solution provided by this invention includes a dehydrogenation reactor to dehydrogenate part of the bottom material of the C6 dehydrogenation tower, resulting in a dehydrogenation product containing a lower degree of unsaturation (i.e., containing more cyclohexylbiphenyl) than the bottom material of the C6 dehydrogenation tower.

[0050] According to the method of the present invention, in preferred step a), the operating conditions of the hydrogenation alkylation reaction include a reaction temperature of 100-250°C, preferably 150-200°C. This reaction temperature is significantly lower than the conventional process's above 600°C, reducing operational difficulty and production costs.

[0051] According to the method of the present invention, in preferred step a), the operating conditions of the hydrogenation alkylation reaction include: a pressure of 0.5-5 MPa, preferably 1-2 MPa.

[0052] According to the method of the present invention, preferably in step a), the operating conditions of the hydroalkylation reaction include: a hydrogen space velocity of 20-200 hr. -1 Preferred duration: 40-100 hours -1 The molar ratio of benzene to hydrogen is 0.1-10:1, preferably 0.5-3:1.

[0053] According to the method of the present invention, preferably in step a), the hydrogenation alkylation reaction catalyst contains at least one Group VIII transition metal element. According to the present invention, the catalyst contains, for example, one or more metal elements selected from ruthenium, platinum, rhodium, etc.

[0054] According to the method of the present invention, preferably in step a), the reactor for the hydrogenation alkylation reaction is one or more of a fixed-bed reactor, a moving-bed reactor, and a trickle-bed reactor.

[0055] According to the method of the present invention, in preferred step b), the operating conditions of the C6 removal tower include a pressure of 20-200 kPa.

[0056] According to the method of the present invention, in step c), the conditions for the dehydrogenation reaction include: a reaction temperature of 200-600°C, preferably 220-400°C.

[0057] According to the method of the present invention, in preferred step c), the conditions for the dehydrogenation reaction include a pressure of 0.5-5 MPa, preferably 1-3.5 MPa.

[0058] According to the method of the present invention, preferably in step c), the conditions for the dehydrogenation reaction include: the dehydrogenation reaction employing a catalyst containing at least one Group VIII transition metal element. The catalyst, for example, is a catalyst containing one or more metal elements such as platinum and palladium.

[0059] According to the method of the present invention, in preferred step d), the operating conditions of the separation tower include a pressure of 1-150 kPa.

[0060] Because impurities such as sulfur and nitrogen in the raw benzene may poison the catalyst and reduce its catalytic activity, denitrification and / or desulfurization and / or dehydration of the raw material are necessary before it enters the hydroalkylation reactor. According to the method of the present invention, the method further includes: the benzene undergoing denitrification and / or desulfurization and / or dehydration treatment before entering the hydroalkylation reactor. Denitrification, desulfurization, and dehydration can extend the catalyst lifetime.

[0061] like Figure 1 As shown, according to a preferred embodiment of the present invention, the present invention provides a method for producing a synthetic thermally conductive medium, the method comprising:

[0062] a) The feed benzene is mixed with C40, a cyclohexylbenzene-rich recycle from the top of the separator. 12 After the raw materials are mixed, they are then mixed with hydrogen and fed into a hydroalkylation reactor to produce dicyclohexylbenzene, cyclohexylbiphenyl, cyclohexylbenzene, cyclohexane, and C64. 18 The reaction products of the above components;

[0063] b) The reaction product is fed into a C6 removal tower, where light components and C6 components are separated at the top of the C6 removal tower. A portion of the C6 components is sent back to the inlet of the hydroalkylation reactor to be mixed with the feed benzene, and the bottom material of the C6 removal tower is obtained at the bottom of the tower.

[0064] c) Feed part or all of the bottom material from the C6 removal tower into the dehydrogenation reactor to generate an incremental dehydrogenation product of cyclohexylbiphenyl.

[0065] d) The dehydrogenation product and the remaining bottoms from the C6 removal tower are fed into a separation tower, from which C6-rich cyclohexylbenzene is separated from the top of the separation tower. 12 The material is recycled back to the hydroalkylation reactor, and the thermally conductive medium is separated from the bottom of the separation tower.

[0066] According to a preferred embodiment of the present invention, the synthetic thermally conductive medium comprises 65-88% dicyclohexylbenzene, 10-25% cyclohexylbiphenyl, and 2-10% heavy components (C 18 (Above), the maximum operating temperature is greater than 330℃.

[0067] According to a preferred embodiment of the present invention, the reactor for the hydroalkylation reaction is one or more of a fixed-bed reactor, a moving-bed reactor, and a trickle-bed reactor. The catalyst is a catalyst containing at least one Group VIII transition metal element. The reaction temperature for the hydroalkylation reaction is 100-250°C, preferably 150-200°C, the pressure is 0.5-5 MPa, preferably 1-2 MPa, and the hydrogen space velocity is 20-200 hr. -1 Preferred duration: 40-100 hours -1 The molar ratio of benzene to hydrogen is 0.1-10:1, preferably 0.5-3:1.

[0068] According to a preferred embodiment of the present invention, the pressure of the C6 removal tower is 20-200 kPa. Light components and C6 components are separated at the top of the C6 removal tower, and part of the bottom stream is sent to the dehydrogenation reactor and part is sent to the separation tower.

[0069] According to a preferred embodiment of the present invention, the dehydrogenation reaction employs a catalyst containing at least one Group VIII transition metal element. The reaction temperature is 200-600°C, preferably 220-400°C, and the pressure is 0.5-5 MPa, preferably 1-3.5 MPa. The ratio of the bottom material from the C6 removal tower to the total bottom material entering the dehydrogenation reactor is 0.05-1:1, preferably 0.1-0.5:1, and the remaining bottom material from the C6 removal tower is sent to a separation tower.

[0070] According to a preferred embodiment of the present invention, the pressure of the separation tower is 1-150 kPa, a product synthesis-type thermal conductivity medium is obtained at the bottom of the separation tower, and C rich in cyclohexylbenzene is obtained at the top of the tower. 12 The feedstock benzene and the top recycle C from the separation tower are recycled back to the hydroalkylation reactor. 12 The quality ratio of logistics is 0.1-10.0:1, with a preferred ratio of 0.5-3.0:1.

[0071] like Figure 1 As shown, the present invention provides a system for the method of synthesizing the thermally conductive medium described in the present invention. The system includes: a hydroalkylation reactor 2, a C6 removal tower 5, a dehydrogenation reactor 4, and a separation tower 10 connected in series along the feed flow direction. The material outlet of the hydroalkylation reactor is connected to the inlet of the C6 removal tower, the material outlet of the C6 removal tower 5 is connected to the inlet of the dehydrogenation reactor, the outlet of the dehydrogenation reactor is connected to the inlet of the separation tower, and the top material outlet of the separation tower is connected to the inlet of the hydroalkylation reactor. Preferably, the material outlet of the C6 removal tower 5 is connected to the inlet of the separation tower 10.

[0072] According to a preferred embodiment of the present invention, the system further includes: a feed heater 1 for the hydroalkylation reactor.

[0073] According to a preferred embodiment of the present invention, the system further includes: a dehydrogenation reactor feed heater 3.

[0074] According to a preferred embodiment of the present invention, the system further includes: a C6 removal tower top condenser 6 and a C6 removal tower reflux tank 7.

[0075] According to a preferred embodiment of the present invention, the system further includes: a reboiler 8 for the C6 removal tower and a discharge pump 9 for the C6 removal tower.

[0076] According to a preferred embodiment of the present invention, the system further includes: a top condenser 11 of the separation tower and a reflux tank 12 of the separation tower.

[0077] According to a preferred embodiment of the present invention, the system further includes: a reboiler 13 in the bottom of the separation tower, a product pump 14, and a product cooler 15.

[0078] Depending on the requirements, the system may also include heat exchangers or coolers installed on various pipelines, with the exchange medium being, for example, cooling water (CW) or high-pressure steam (HS).

[0079] Schematic diagrams of the system and method of the present invention are shown below. Figure 1 As shown, where:

[0080] 1-Feed heater for hydroalkylation reactor; 2-Hydroalkylation reactor; 3-Feed heater for dehydrogenation reactor; 4-Dehydrogenation reactor; 5-C6 removal tower; 6-C6 removal tower overhead condenser; 7-C6 removal tower reflux tank; 8-C6 removal tower bottom reboiler; 9-C6 removal tower discharge pump; 10-Separation tower; 11-Separation tower overhead condenser; 12-Separation tower reflux tank; 13-Separation tower bottom reboiler; 14-Product pump; 15-Product cooler.

[0081] In this invention, all pressure refers to absolute pressure.

[0082] The invention will be further illustrated below with reference to embodiments and comparative examples.

[0083] Example 1

[0084] A certain 10,000-ton / year synthetic thermal conductivity medium production unit (8,000 operating hours per year) has the following process flow: Figure 1 As shown, the equipment includes a hydroalkylation reactor, a dehydrogenation reactor, a C6 removal tower, and a separation tower, etc., and the rest of the embodiments are the same.

[0085] The feedstock benzene is combined with C40, a cyclohexylbenzene-rich recycle from the top of the separator. 12After being mixed with other materials, the mixture is then mixed with hydrogen and fed into a hydroalkylation reactor to produce dicyclohexylbenzene, cyclohexylbiphenyl, cyclohexylbenzene, and cyclohexane. The hydroalkylation reaction uses a ruthenium-supported catalyst (0.08 wt%), with a feed temperature of 150°C, a discharge temperature of 180°C, a pressure of 2 MPa, and a hydrogen space velocity of 50 hr⁻¹. -1 The molar ratio of benzene to hydrogen is 2.8:1. The benzene feed flow rate is 1755 kg / hr, and the hydrogen feed flow rate is 50 kg / hr. The hydrogen is recycled from the top of the product column. 12 The flow rate of the materials was 3510 kg / hr, and the mass ratio of the two was 0.5. The hydroalkylation reaction product was fed into a C6 removal column, with a pressure of 100 kPaA, a reflux ratio of 2.3, and a bottom temperature of 240°C. The light components at the top of the column mainly consisted of unreacted hydrogen and small amounts of cyclohexane and benzene, with a flow rate of 30 kg / hr. The top reflux tank collected C6 byproducts containing benzene and cyclohexane at a flow rate of 300 kg / h. Part of the bottom material from the C6 removal column was fed into a dehydrogenation reactor, controlling the ratio of the partial C6 removal column bottom material to the total C6 removal column bottom material entering the dehydrogenation reactor to be 0.2:1, resulting in a dehydrogenation product with a lower degree of unsaturation than the bottom material from the C6 removal column. The dehydrogenation reaction used a platinum-containing catalyst (platinum content 5% wt based on oxides, Al2O3 support, the same in the following examples), with a reaction feed temperature of 350°C and a pressure of 2.5 MPa. The dehydrogenation product and the remaining C6 removal column bottoms material are mixed and then fed into the separation column. The separation column operates at a pressure of 110 kPaA, a reflux ratio of 1.5, a column bottom temperature of 280℃, and the flow rate of the synthetic thermal conductivity medium collected from the bottom of the column is 1250 kg / hr.

[0086] The method yielded a 71.2% yield of thermally conductive media. (Yield = Product flow rate / Feed flow rate, the same below)

[0087] The high-temperature synthetic thermal conductivity medium has a weight composition of 83% dicyclohexylbenzene, 13% cyclohexylbiphenyl, and 4% heavy components. It has a maximum operating temperature of 350℃. After thermal oxidation stability testing, the oil remains clear with no obvious solid sediment, demonstrating excellent performance.

[0088] Example 2

[0089] The same production apparatus as in Example 1 was used.

[0090] The original benzene was combined with C20, a cyclohexylbenzene-rich compound from the top recycle of the separation column. 12 After mixing, the raw materials are then mixed with hydrogen and fed into a hydroalkylation reactor to produce dicyclohexylbenzene, cyclohexylbiphenyl, cyclohexylbenzene, and cyclohexane. The hydroalkylation reaction uses a ruthenium-containing catalyst (ruthenium content 0.08% wt), with a feed temperature of 150°C, a discharge temperature of 200°C, a pressure of 2.5 MPa, and a hydrogen space velocity of 100 hr.-1 The molar ratio of benzene to hydrogen is 1.5:1. The benzene feed flow rate is 1900 kg / hr, and the hydrogen feed flow rate is 100 kg / hr. Benzene is recycled from the top of the separation tower. 12 The flow rate of the materials was 1900 kg / hr, and the mass ratio of the two was 1. The hydroalkylation reaction product was fed into a C6 removal column, with a pressure of 100 kPaA, a reflux ratio of 2.3, and a bottom temperature of 240°C. The light components at the top of the column mainly consisted of unreacted hydrogen and small amounts of cyclohexane and benzene, with a flow rate of 105 kg / hr. The top reflux tank collected C6 byproducts containing benzene and cyclohexane at a flow rate of 345 kg / h. Part of the bottom material from the C6 removal column was fed into a dehydrogenation reactor. The ratio of the partial C6 removal column bottom material to the total C6 removal column bottom material entering the dehydrogenation reactor was controlled at 0.1:1, resulting in a dehydrogenated product with a lower degree of unsaturation than the bottom material from the C6 removal column. The dehydrogenation reaction used a platinum-containing catalyst, with a feed temperature of 220°C and a pressure of 2 MPa. The dehydrogenation product and the remaining C6 removal column bottoms material are mixed and then fed into the separation column. The separation column is operated under vacuum with a column pressure of 20 kPaA, a reflux ratio of 2.0, a column bottom temperature of 251°C, and a production flow rate of 1250 kg / hr for the synthetic thermal conductivity medium collected from the bottom of the column.

[0091] The yield of the synthesized thermal conductive medium using this technology is 65.7%.

[0092] The high-temperature synthetic thermal conductivity medium has a weight composition of 76% dicyclohexylbenzene, 19% cyclohexylbiphenyl, and 5% heavy components. Its maximum operating temperature is 380℃. After thermal oxidation stability testing, the oil remains clear with no obvious solid sediment, demonstrating excellent performance.

[0093] Example 3

[0094] The same production apparatus as in Example 1 was used.

[0095] The feedstock benzene is combined with C20, a cyclohexylbenzene-rich recycle from the top of the product column. 12 After mixing, the raw materials are then mixed with hydrogen and fed into a hydroalkylation reactor to produce dicyclohexylbenzene, cyclohexylbiphenyl, cyclohexylbenzene, and cyclohexane. The hydroalkylation reaction uses a ruthenium-containing catalyst (ruthenium content 0.08% wt), with a feed temperature of 160°C, a discharge temperature of 190°C, a pressure of 3 MPa, and a hydrogen space velocity of 40 hr⁻¹. -1 The molar ratio of benzene to hydrogen is 3:1. The benzene feed flow rate is 1800 kg / hr, and the hydrogen feed flow rate is 40 kg / hr. Benzene is recycled from the top of the separator. 12The flow rate of the materials is 1200 kg / hr, and the mass ratio of the two is 1.5. The hydroalkylation reaction product is fed into a C6 removal column, with a pressure of 110 kPaA, a reflux ratio of 2.2, and a bottom temperature of 246°C. The light components at the top of the column mainly consist of unreacted hydrogen and small amounts of cyclohexane and benzene, with a flow rate of 185 kg / hr. The top reflux tank collects C6 byproducts containing benzene and cyclohexane, with a flow rate of 265 kg / h. Part of the bottom material from the C6 removal column is fed into a dehydrogenation reactor. The ratio of the partial C6 removal column bottom material to the total C6 removal column bottom material entering the dehydrogenation reactor is controlled at 0.3:1, yielding a dehydrogenated product with a lower degree of unsaturation than the C6 removal column bottom material. The dehydrogenation reaction uses a platinum-containing catalyst, with a feed temperature of 250°C and a pressure of 2.0 MPa. The dehydrogenation product and the remaining C6 removal column bottoms material are mixed and then fed into the separation column. The separation column is operated under vacuum with a column pressure of 10 kPa, a reflux ratio of 3.0, a column bottom temperature of 252°C, and a production flow rate of 1250 kg / hr of the synthetic thermal conductivity medium collected from the bottom of the column.

[0096] The method yielded a 69.4% yield of synthetic thermally conductive media.

[0097] The high-temperature synthetic thermal conductivity medium has a weight composition of 72% dicyclohexylbenzene, 22% cyclohexylbiphenyl, and 6% heavy components. Its maximum operating temperature is 370℃. After thermal oxidation stability testing, the oil remains clear with no obvious solid sediment, demonstrating excellent performance.

[0098] Example 4

[0099] The same production apparatus as in Example 1 was used.

[0100] The feedstock benzene is combined with C20, a cyclohexylbenzene-rich recycle from the top of the product column. 12 After mixing, the raw materials are then mixed with hydrogen and fed into a hydroalkylation reactor to produce dicyclohexylbenzene, cyclohexylbiphenyl, cyclohexylbenzene, and cyclohexane. The hydroalkylation reaction uses a ruthenium-containing catalyst (ruthenium content 0.08% wt), with a feed temperature of 150°C, a discharge temperature of 180°C, a pressure of 1.5 MPa, and a hydrogen space velocity of 50 hr⁻¹. -1 The molar ratio of benzene to hydrogen is 2.5:1. The benzene feed flow rate is 1875 kg / hr, and the hydrogen feed flow rate is 50 kg / hr. Benzene is recycled from the top of the separation tower. 12The flow rate of the materials was 938 kg / hr, and the mass ratio of the two was 2. The hydroalkylation reaction product was fed into a C6 removal column, with a pressure of 120 kPaA, a reflux ratio of 2.6, and a bottom temperature of 253°C. The light components at the top of the column mainly consisted of unreacted hydrogen and small amounts of cyclohexane and benzene, with a flow rate of 235 kg / hr. The top reflux tank collected C6 byproducts containing benzene and cyclohexane at a flow rate of 260 kg / h. Part of the bottom material from the C6 removal column was fed into a dehydrogenation reactor. The ratio of the partial C6 removal column bottom material to the total C6 removal column bottom material entering the dehydrogenation reactor was controlled at 0.4:1, resulting in a dehydrogenated product with a lower degree of unsaturation than the bottom material from the C6 removal column. The dehydrogenation reaction used a platinum-containing catalyst, with a feed temperature of 400°C and a pressure of 3.5 MPa. The dehydrogenation product and the remaining C6 removal column bottoms material are mixed and then fed into the separation column. The separation column is operated under vacuum with a column pressure of 10 kPa, a reflux ratio of 3.0, a column bottom temperature of 241°C, and a production flow rate of 1250 kg / hr of the synthetic thermal conductivity medium collected from the bottom of the column.

[0101] The method yields a 66.7% synthetic thermal conductivity medium.

[0102] The high-temperature synthetic thermal conductivity medium has a weight composition of 73% dicyclohexylbenzene, 20% cyclohexylbiphenyl, and 7% heavy components. It has a maximum operating temperature of 360℃. After thermal oxidation stability testing, the oil remains clear with no obvious solid sediment, demonstrating excellent performance.

[0103] Example 5

[0104] The same production apparatus as in Example 1 was used.

[0105] The feedstock benzene is combined with C20, a cyclohexylbenzene-rich recycle from the top of the product column. 12 After being mixed with other materials, the mixture is then mixed with hydrogen and fed into a hydroalkylation reactor to produce dicyclohexylbenzene, cyclohexylbiphenyl, cyclohexylbenzene, and cyclohexane. The hydroalkylation reaction uses a platinum-containing catalyst (0.1% wt) at a feed temperature of 150°C, a discharge temperature of 180°C, a pressure of 2 MPa, and a hydrogen space velocity of 60 hr⁻¹. -1 The molar ratio of benzene to hydrogen is 2.1:1. The benzene feed flow rate is 2070 kg / hr, and the hydrogen feed flow rate is 60 kg / hr. Benzene is recycled from the top of the product column. 12The flow rate of the materials was 690 kg / hr, and the mass ratio of the two was 3. The hydroalkylation reaction product was fed into a C6 removal column, with a pressure of 110 kPaA, a reflux ratio of 2.2, and a bottom temperature of 246°C. The light components at the top of the column mainly consisted of unreacted hydrogen and small amounts of cyclohexane and benzene, with a flow rate of 285 kg / hr. The top reflux tank collected C6 byproducts containing benzene and cyclohexane at a flow rate of 330 kg / h. Part of the bottom material from the C6 removal column was fed into a dehydrogenation reactor, controlling the ratio of the partial C6 removal column bottom material to the total C6 removal column bottom material entering the dehydrogenation reactor to be 0.5:1, resulting in a dehydrogenation product with a lower degree of unsaturation than the bottom material from the C6 removal column. The dehydrogenation reaction used a palladium-containing catalyst (palladium content 5% wt based on oxides, Al2O3 support, the same in the following examples), with a reaction feed temperature of 600°C and a pressure of 5.0 MPa. The dehydrogenation product and the remaining C6 removal column bottoms material are mixed and then fed into the separation column. The separation column is operated under vacuum with a column pressure of 10 kPa, a reflux ratio of 5.0, a column bottom temperature of 235°C, and a production flow rate of 1250 kg / hr of the synthetic thermal conductivity medium collected from the bottom of the column.

[0106] The method yields a 60.4% synthetic thermal conductivity medium.

[0107] The high-temperature synthetic thermal conductivity medium has a weight composition of 78% dicyclohexylbenzene, 16% cyclohexylbiphenyl, and 6% heavy components. It has a maximum operating temperature of 350℃. After thermal oxidation stability testing, the oil remains clear with no obvious solid sediment, demonstrating excellent performance.

[0108] Example 6

[0109] The same production apparatus as in Example 1 was used.

[0110] The feedstock benzene is combined with C20, a cyclohexylbenzene-rich recycle from the top of the product column. 12 After being mixed with other materials, the mixture is then mixed with hydrogen and fed into a hydroalkylation reactor to produce dicyclohexylbenzene, cyclohexylbiphenyl, cyclohexylbenzene, and cyclohexane. The hydroalkylation reaction uses a platinum-containing catalyst (0.1% wt) at a feed temperature of 200°C, a discharge temperature of 250°C, a pressure of 5 MPa, and a hydrogen space velocity of 200 hr⁻¹. -1 The molar ratio of benzene to hydrogen is 0.7:1. The benzene feed flow rate is 1800 kg / hr, and the hydrogen feed flow rate is 200 kg / hr. Benzene is recycled from the top of the product column. 12The flow rate of the materials is 180 kg / hr, and the mass ratio of the two is 10. The hydroalkylation reaction product is fed into a C6 removal column, with a pressure of 110 kPaA, a reflux ratio of 2.2, and a bottom temperature of 246°C. The light components at the top of the column mainly consist of unreacted hydrogen and small amounts of cyclohexane and benzene, with a flow rate of 305 kg / hr. The top reflux tank collects C6 byproducts containing benzene and cyclohexane, with a flow rate of 244 kg / h. Part of the bottom material from the C6 removal column is fed into a dehydrogenation reactor. The ratio of the partial C6 removal column bottom material to the total C6 removal column bottom material entering the dehydrogenation reactor is controlled at 0.2:1, resulting in a dehydrogenated product with a lower degree of unsaturation than the bottom material from the C6 removal column. The dehydrogenation reaction uses a palladium-containing catalyst, with a feed temperature of 200°C and a pressure of 0.5 MPa. The dehydrogenation product and the remaining C6 removal column bottoms material are mixed and then fed into the separation column. The separation column is operated under vacuum with a column pressure of 15 kPa, a reflux ratio of 3.0, a column bottom temperature of 251°C, and a production flow rate of 1250 kg / hr for the synthetic thermal conductivity medium collected from the bottom of the column.

[0111] The method yields a 70.8% synthetic thermal conductivity medium.

[0112] The high-temperature synthetic thermal conductivity medium has a weight composition of 88% dicyclohexylbenzene, 10% cyclohexylbiphenyl, and 2% heavy components. Its maximum operating temperature is 340℃. After thermal oxidation stability testing, the oil remains clear with no obvious solid sediment, demonstrating excellent performance.

[0113] Example 7

[0114] The same production apparatus as in Example 1 was used.

[0115] The feedstock benzene is combined with C40, a cyclohexylbenzene-rich recycle from the top of the separator. 12 After being mixed with other materials, the mixture is then mixed with hydrogen and fed into a hydroalkylation reactor to produce dicyclohexylbenzene, cyclohexylbiphenyl, cyclohexylbenzene, and cyclohexane. The hydroalkylation reaction uses a rhodium-containing catalyst (0.15% wt) at a feed temperature of 150°C, a discharge temperature of 170°C, a pressure of 1 MPa, and a hydrogen space velocity of 45 h⁻¹. -1 The molar ratio of benzene to hydrogen is 2.8:1. The benzene feed flow rate is 1820 kg / hr, and the hydrogen feed flow rate is 45 kg / hr. The hydrogen is recycled from the top of the separation tower. 12The flow rate of the materials was 607 kg / hr, and the mass ratio of the two was 3. The hydroalkylation reaction product was fed into a C6 removal column, with a pressure of 110 kPaA, a reflux ratio of 2.2, and a bottom temperature of 246 °C. The light component at the top of the column mainly consisted of unreacted hydrogen and small amounts of cyclohexane and benzene, with a flow rate of 195 kg / hr. The top reflux tank collected C6 byproducts containing benzene and cyclohexane at a flow rate of 296 kg / h. Part of the bottom material from the C6 removal column was fed into a dehydrogenation reactor. The ratio of the partial C6 removal column bottom material to the total C6 removal column bottom material entering the dehydrogenation reactor was controlled at 0.3:1, resulting in a dehydrogenated product with a lower degree of unsaturation than the bottom material from the C6 removal column. The dehydrogenation reaction used a palladium-containing catalyst, with a feed temperature of 300 °C and a pressure of 2.0 MPa. The dehydrogenation product and the remaining C6 removal column bottoms material are mixed and then fed into the separation column. The separation column is operated under vacuum with a column pressure of 50 kPa, a reflux ratio of 3.0, a column bottom temperature of 265°C, and a production flow rate of 1250 kg / hr for the synthetic thermal conductivity medium collected from the bottom of the column.

[0116] The method yields a 68.6% synthetic thermal conductivity medium.

[0117] The high-temperature synthetic thermal conductivity medium has a weight composition of 79% dicyclohexylbenzene, 15% cyclohexylbiphenyl, and 6% heavy components. It has a maximum operating temperature of 350℃. After thermal oxidation stability testing, the oil remains clear with no obvious solid sediment, demonstrating excellent performance.

[0118] Example 8

[0119] The same production apparatus as in Example 1 was used.

[0120] The feedstock benzene is combined with C40, a cyclohexylbenzene-rich recycle from the top of the separator. 12 After being mixed with other materials, the mixture is then mixed with hydrogen and fed into a hydroalkylation reactor to produce dicyclohexylbenzene, cyclohexylbiphenyl, cyclohexylbenzene, and cyclohexane. The hydroalkylation reaction uses a rhodium-containing catalyst (0.15% wt) at a feed temperature of 100°C, a discharge temperature of 130°C, a pressure of 0.5 MPa, and a hydrogen space velocity of 20 h⁻¹. -1 The molar ratio of benzene to hydrogen is 10:1. The benzene feed flow rate is 2290 kg / hr, and the hydrogen feed flow rate is 20 kg / hr. Benzene is recycled from the top of the separation tower. 12The flow rate of the materials was 2290 kg / hr, and the mass ratio of the two was 1. The hydroalkylation reaction product was fed into a C6 removal column at a pressure of 200 kPaA, a reflux ratio of 2.2, and a bottom temperature of 267°C. The light components at the top of the column mainly consisted of unreacted hydrogen and small amounts of cyclohexane and benzene, with a flow rate of 460 kg / hr. The top reflux tank collected C6 byproducts containing benzene and cyclohexane at a flow rate of 400 kg / h. Part of the bottom material from the C6 removal column was fed into a dehydrogenation reactor. The ratio of the partial C6 removal column bottom material to the total C6 removal column bottom material entering the dehydrogenation reactor was controlled at 0.8:1, resulting in a dehydrogenated product with a lower degree of unsaturation than the bottom material from the C6 removal column. The dehydrogenation reaction used a palladium-containing catalyst, with a feed temperature of 250°C and a pressure of 2.0 MPa. The dehydrogenation product and the remaining C6 removal column bottoms material are mixed and then fed into the separation column. The separation column is operated under vacuum with a column pressure of 10 kPa, a reflux ratio of 1.8, a column bottom temperature of 247°C, and a production flow rate of 1250 kg / hr of the synthetic thermal conductivity medium collected from the bottom of the column.

[0121] The method yielded a 54.6% yield of synthetic thermally conductive media.

[0122] The high-temperature synthetic thermal conductivity medium has a weight composition of 74% dicyclohexylbenzene, 18% cyclohexylbiphenyl, and 8% heavy components. It has a maximum operating temperature of 360℃. After thermal oxidation stability testing, the oil remains clear with no obvious solid sediment, demonstrating excellent performance.

[0123] Example 9

[0124] The same production apparatus as in Example 1 was used.

[0125] The feedstock benzene is combined with C20, a cyclohexylbenzene-rich recycle from the top of the product column. 12 After mixing, the raw materials are then mixed with hydrogen and fed into a hydroalkylation reactor to produce dicyclohexylbenzene, cyclohexylbiphenyl, cyclohexylbenzene, and cyclohexane. The hydroalkylation reaction uses a platinum-containing catalyst (0.1% wt) at a feed temperature of 150°C, a discharge temperature of 180°C, a pressure of 1.5 MPa, and a hydrogen space velocity of 50 hr⁻¹. -1 The molar ratio of benzene to hydrogen is 2.5:1. The benzene feed flow rate is 2485 kg / hr, and the hydrogen feed flow rate is 50 kg / hr. Benzene is recycled from the top of the separator. 12The flow rate of the materials was 2982 kg / hr, and the mass ratio of the two was 0.8. The hydroalkylation reaction product was fed into a C6 removal column at a pressure of 50 kPaA, a reflux ratio of 2.8, and a bottom temperature of 223°C. The light components at the top of the column mainly consisted of unreacted hydrogen and small amounts of cyclohexane and benzene, with a flow rate of 535 kg / hr. The top reflux tank collected C6 byproducts containing benzene and cyclohexane at a flow rate of 385 kg / h. Part of the bottom material from the C6 removal column was fed into a dehydrogenation reactor. The ratio of the partial C6 removal column bottom material to the total C6 removal column bottom material entering the dehydrogenation reactor was controlled at 1:1 to obtain a dehydrogenated product with a lower degree of unsaturation than the bottom material from the C6 removal column. The dehydrogenation reaction used a platinum-containing catalyst, with a feed temperature of 220°C and a pressure of 1.0 MPa. The dehydrogenation product enters the C6 removal tower. The product tower pressure is 101 kPa, the reflux ratio is 1.8, the tower bottom temperature is 270℃, and the flow rate of the synthetic thermal conductive medium collected from the bottom of the tower is 1250 kg / hr.

[0126] The method yields a 50.3% synthetic thermal conductivity medium.

[0127] The high-temperature synthetic thermal conductivity medium has a weight composition of 65% dicyclohexylbenzene, 25% cyclohexylbiphenyl, and 10% heavy components. Its maximum operating temperature is 330℃. After thermal oxidation stability testing, the oil remains clear with no obvious solid sediment, demonstrating excellent performance.

[0128] Example 10

[0129] The same production apparatus as in Example 1 was used.

[0130] The feedstock benzene is combined with C20, a cyclohexylbenzene-rich recycle from the top of the product column. 12 After mixing, the raw materials are then mixed with hydrogen and fed into a hydroalkylation reactor to produce dicyclohexylbenzene, cyclohexylbiphenyl, cyclohexylbenzene, and cyclohexane. The hydroalkylation reaction uses a ruthenium-containing catalyst (ruthenium content 0.08% wt), with a feed temperature of 160°C, a discharge temperature of 190°C, a pressure of 2.0 MPa, and a hydrogen space velocity of 60 hr⁻¹. -1 The molar ratio of benzene to hydrogen is 2.1:1. The benzene feed flow rate is 1685 kg / hr, and the hydrogen feed flow rate is 60 kg / hr. The hydrogen is recycled from the top of the product column. 12The flow rate of the materials was 2310 kg / hr, and the mass ratio of the two was 0.7. The hydroalkylation reaction product was fed into a C6 removal column at a pressure of 20 kPaA, a reflux ratio of 2.2, and a bottom temperature of 202°C. The light component at the top of the column mainly consisted of unreacted hydrogen and small amounts of cyclohexane and benzene, with a flow rate of 87 kg / hr. The top reflux tank collected C6 byproducts containing benzene and cyclohexane at a flow rate of 350 kg / h. Part of the bottom material from the C6 removal column was fed into a dehydrogenation reactor. The ratio of the partial C6 removal column bottom material to the total C6 removal column bottom material entering the dehydrogenation reactor was controlled at 0.05:1, resulting in a dehydrogenated product with a lower degree of unsaturation than the bottom material from the C6 removal column. The dehydrogenation reaction used a palladium-containing catalyst, with a feed temperature of 400°C and a pressure of 3.0 MPa. The dehydrogenation product and the remaining C6 removal column bottoms material are mixed and then fed into the separation column. The separation column is operated under vacuum with a column pressure of 1 kPa, a reflux ratio of 1.8, a column bottom temperature of 195°C, and a production flow rate of 1250 kg / hr of the synthetic thermal conductivity medium collected from the bottom of the column.

[0131] The method yielded a 74.1% synthetic thermal conductivity medium.

[0132] The high-temperature synthetic thermal conductivity medium has a weight composition of 82% dicyclohexylbenzene, 14% cyclohexylbiphenyl, and 4% heavy components. It has a maximum operating temperature of 350℃. After thermal oxidation stability testing, the oil remains clear with no obvious solid sediment, demonstrating excellent performance.

[0133] Comparative Example 1

[0134] A 0.5 million ton / year synthetic thermal conductivity medium production system (8000 operating hours per year) adopts a traditional process route: benzene undergoes high-temperature condensation and dehydrogenation to produce biphenyl, with terphenyl as a byproduct. Terphenyl is then hydrogenated to produce the synthetic thermal conductivity medium. Pure benzene and catalyst are fed into an evaporator to vaporize the materials, which are then fed into a cracking furnace for cracking at 680°C to produce biphenyl and terphenyl. The crude biphenyl is pumped into a crude distillation column, and the overhead stream is then fed into a batch distillation vessel. The initial fraction is residual benzene, the middle fraction is biphenyl, and the residue in the vessel is terphenyl. The terphenyl is then fed into a hydrogenation reactor to react with hydrogen to produce the synthetic thermal conductivity medium.

[0135] The yield of the synthetic thermally conductive medium was 9%, which is far lower than the level of the example.

[0136] The high-temperature synthetic thermal conductivity medium has a weight composition of 66% dicyclohexylbenzene, 30% cyclohexylbiphenyl, 3% terphenyl, and 1% heavy components. Its maximum operating temperature is 300℃. After thermal oxidation stability testing, the oil turns black and becomes cloudy, indicating poor thermal oxidation stability.

[0137] Table 1

[0138]

[0139] Table 1 - Continued

[0140]

[0141] If the data in the table differs from the example data, the data in the example data shall prevail.

[0142] As can be clearly seen from the data in Table 1, compared with the traditional process shown in Comparative Example 1, the thermally conductive medium synthesized by this invention has significant advantages, including a higher operating temperature and superior oxidation stability. More importantly, the production method provided by this invention has a lower production temperature and a higher product yield. Specifically, the reaction temperature is reduced from above 600°C to below 250°C, and the yield of the synthesized thermally conductive medium is increased from below 10% to above 50%. The technical advantages are quite obvious.

[0143] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. However, these simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A synthetic thermally conductive medium, characterized in that, Based on the total weight of the synthesized thermally conductive medium, it contains 65-88% dicyclohexylbenzene, 10-25% cyclohexylbiphenyl, and 2-10% other C4 compounds. 18 The above-mentioned recombinant components have a maximum operating temperature greater than 330℃; the other C... 18 The above-mentioned recombinant components contain tricyclohexylbenzene and / or dicyclohexylbiphenyl.

2. The synthetic thermally conductive medium according to claim 1, wherein, The synthetic thermally conductive medium is used at a temperature of 330-380℃.

3. A method for synthesizing a thermally conductive medium, characterized in that, The method includes: a) Benzene and hydrogen are fed into a hydroalkylation reactor for reaction, producing dicyclohexylbenzene, cyclohexylbiphenyl, cyclohexylbenzene, cyclohexane, and C64. 18 The reaction products of the above components; b) The reaction product is fed into a C6 removal tower, and light components and C6 components are separated from the top of the C6 removal tower. Optionally, a portion of the C6 components is sent back to the inlet of the hydroalkylation reactor to be mixed with the feed benzene, and the bottom material of the C6 removal tower is obtained at the bottom of the tower. c) Feed part or all of the bottom material of the C6 removal tower into the dehydrogenation reactor for dehydrogenation to obtain an incremental dehydrogenation product of cyclohexylbiphenyl; d) The dehydrogenation product and, optionally, the remaining bottoms from the C6 dehydrogenation column are fed into a separation column to separate C6-rich cyclohexylbenzene-containing C6 from the top of the separation column. 12 The material is a thermally conductive medium separated from the bottom of the separation tower. Based on the total weight of the thermally conductive medium, this synthetic thermally conductive medium contains 65-88% dicyclohexylbenzene, 10-25% cyclohexylbiphenyl, and 2-10% other C4 compounds. 18 The above-mentioned recombinant components have a maximum operating temperature of over 330℃; The other C 18 The above-mentioned recombinant components contain tricyclohexylbenzene and / or dicyclohexylbiphenyl.

4. The method according to claim 3, wherein, The synthetic thermally conductive medium is used at a temperature of 330-380℃.

5. The method according to claim 3, wherein, The ratio of the bottom material of the C6 removal tower entering the dehydrogenation reactor to the bottom material of the entire C6 removal tower is 0.05-1:

1.

6. The method according to claim 5, wherein, The ratio of the bottom material of the C6 removal tower entering the dehydrogenation reactor to the bottom material of the entire C6 removal tower is 0.1-0.5:

1.

7. The method according to claim 3 or 4, wherein, The method also includes separating the C-rich cyclohexylbenzene-rich C-type material from the top of the separation column. 12 The logistics are returned as reaction raw materials for step a).

8. The method according to claim 7, wherein, The raw material benzene and the recycled C20 rich in cyclohexylbenzene 12 The quality ratio of logistics is 0.1-10.0 :

1.

9. The method according to claim 8, wherein, The raw material benzene and the recycled C20 rich in cyclohexylbenzene 12 The quality ratio of logistics is 0.5-3.0 :

1.

10. The method according to claim 7, wherein, The method includes: a) The feed benzene is mixed with C40, a cyclohexylbenzene-rich recycle from the top of the separator. 12 After the raw materials are mixed, they are then mixed with hydrogen and fed into a hydroalkylation reactor to produce a product containing dicyclohexylbenzene, cyclohexylbiphenyl, cyclohexylbenzene, cyclohexane, and C64. 18 The reaction products of the above components; b) The reaction product is fed into a C6 removal tower, where light components and C6 components are separated at the top of the C6 removal tower. A portion of the C6 components is sent back to the inlet of the hydroalkylation reactor to be mixed with the feed benzene, and the bottom material of the C6 removal tower is obtained at the bottom of the tower. c) A portion of the bottom material from the C6 removal tower is fed into the dehydrogenation reactor for dehydrogenation to generate an incremental dehydrogenation product of cyclohexylbiphenyl. d) The dehydrogenation product and the remaining bottoms material from the C6 removal tower are fed into a separation tower, from which C6-rich cyclohexylbenzene is separated from the top of the separation tower. 12 The logistics process involves separating the thermally conductive medium from the bottom of the separation tower, and then transferring the C-rich cyclohexylbenzene-rich C-material obtained from the top of the tower. 12 The logistics are recycled back to the hydrogenation alkylation reactor.

11. The method according to claim 3 or 4, wherein, In step a), The operating conditions of the hydrogenation alkylation reactor include: The reaction temperature is 100-250℃; and / or the pressure is 0.5-5 MPa; and / or the hydrogen space velocity is 20-200 hr. -1 ; and / or the molar ratio of benzene to hydrogen is 0.1-10 : 1; and / or the hydroalkylation reactor uses a catalyst containing at least one Group VIII transition metal element; and / or The hydroalkylation reactor is one or more of a fixed-bed reactor, a moving-bed reactor, and a trickle-bed reactor; and / or In step b), The operating conditions of the C6 removal column include: pressure of 20-200 kPa, column bottom temperature of 200-260℃, and reflux ratio of 1-3; and / or In step c), The conditions for the dehydrogenation reaction include: a reaction temperature of 200-600℃; a pressure of 0.5-5 MPa; and / or The dehydrogenation reaction uses a catalyst containing at least one Group VIII transition metal element; and / or The dehydrogenation product and the remaining C6 removal column bottoms material are mixed and then fed into the same location in the separation column, or into different locations in the separation column; and / or In step d), The operating conditions of the separation tower include: pressure of 1-150 kPa, bottom temperature of 200-300℃, and reflux ratio of 1-5.

12. The method according to claim 11, wherein, In step a), The operating conditions of the hydrogenation alkylation reactor include: The reaction temperature is 150-200℃; and / or the pressure is 1-3 MPa; and / or the hydrogen space velocity is 40-100 hr. -1 ; and / or the molar ratio of benzene to hydrogen is 0.5-3 : 1; and / or In step c), The conditions for the dehydrogenation reaction include: a reaction temperature of 220-400℃ and a pressure of 1-3.5MPa.

13. The method according to claim 3 or 4, wherein, The method further includes: the benzene undergoing denitrification and / or desulfurization and / or dehydration treatment before entering the hydrogenation alkylation reactor.

14. The method according to claim 3 or 4, wherein, The system used in this method includes: A hydroalkylation reactor, a C6 removal tower, a dehydrogenation reactor, and a separation tower are connected in series along the feed flow direction. The material outlet of the hydroalkylation reactor is connected to the feed inlet of the C6 removal tower, the bottom material outlet of the C6 removal tower is connected to the feed inlet of the dehydrogenation reactor, the outlet of the dehydrogenation reactor is connected to the feed inlet of the separation tower, and the top material outlet of the separation tower is connected to the feed inlet of the hydroalkylation reactor.

15. The method according to claim 14, wherein, The system also includes: The reactor includes a feed heater for a hydroalkylation reactor, a feed heater for a dehydrogenation reactor, a top condenser and a reflux tank for a C6 removal tower, a reboiler and a discharge pump for a C6 removal tower, a top condenser and a reflux tank for a separation tower, a reboiler and a product pump for a separation tower, and a product condenser.

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