Method for comprehensive utilization of ethylene cracking c5

Abstract

The present application relates to a kind of comprehensive utilization method of ethylene cracking C5, comprising the following steps: (1) ethylene cracking C5 by thermal polymerization reaction, alkyn component, cyclopentadiene (CPD) is polymerized to generate mixture (F2);(2) the material obtained in the first step is sent to separation column separation, the bottom material is sent to flash tank, after removing heavy component, DCPD hydrogenation resin polymerization raw material is obtained, the top is obtained separation product (F3);(3)the separation product (F3) obtained in the second step is sent to extraction unit, and elastomer raw material and curing agent special material are obtained.The process flow of the present application is simple, production energy consumption is low, the requirement to equipment is not high, and it is suitable for scale production application.

Description

Technical Field

[0001] This invention belongs to the field of by-product utilization of ethylene plants, and specifically relates to a comprehensive utilization method for C5 from ethylene cracking. Background Technology

[0002] The C5 fraction produced as a byproduct of ethylene plant cracking contains dienes such as isoprene, isoprene, and cyclopentadiene, as well as alkanes, monoolefins, and alkynes. Due to the large number of components and their similar boiling points, separation is difficult. Currently, most domestic C5 cracking separation processes focus on the fine separation of the three dienes (isoprene, isoprene, and cyclopentadiene) to obtain high-purity dicyclopentadiene, polymer-grade isoprene, and isoprene. The mainstream domestic methods are the DMF and ACN methods for fine separation, or the de-ringing C5 coarse separation process. These separation methods are currently very mature and widely used.

[0003] However, existing C5 cracking and refining processes involve very long tower processes and high separation costs. Given the rising energy costs, C5 refining units are no longer profitable. While the C5 cracking and coarse separation process is relatively simple, it still requires a C4 removal process, which also increases separation costs. Furthermore, isoprene and isoprene cannot be separated, and the dienes from C5 cracking cannot be effectively utilized.

[0004] Therefore, how to save separation energy consumption, optimize separation routes, and reduce the comprehensive utilization cost of cracked C5 are technical problems that the industry urgently needs to solve. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a comprehensive utilization method for ethylene cracking C5. The method has a simple process flow, low energy consumption, low equipment requirements, and is suitable for large-scale production.

[0006] This invention provides a method for the comprehensive utilization of C5 from ethylene cracking, comprising the following steps:

[0007] (1) The ethylene cracking C5 is fed into a polymerization reactor and the alkyne component and cyclopentadiene are polymerized by thermal polymerization to produce a mixture;

[0008] (2) The mixture obtained in step (1) is fed into a separation tower for separation. Crude dicyclopentadiene DCPD hydrogenation resin polymerization raw material is obtained at the bottom of the tower, and the separation product is obtained at the top of the tower.

[0009] (3) The crude DCPD hydrogenated resin polymer raw material obtained in step (2) is fed into the second flash tank for de-gravity separation. The refined DCPD hydrogenated resin raw material obtained from the top of the tank is used to enter the hydrogenated resin process to produce DCPD hydrogenated resin. The heavy components obtained from the bottom of the tank are used (through the third transfer pump) to enter the thermopolymer resin process to produce dark thermopolymer resin.

[0010] (4) The separation product obtained in step (2) is fed into an extraction tower. The remaining C5 raw material is separated at the top of the tower, and the extraction product is separated at the bottom of the tower.

[0011] (5) The extraction product obtained in step (4) is sent to the first flash tank. The extractant obtained at the bottom of the tank is returned to the extraction tower for reuse via the second transfer pump. The flash product is obtained at the top of the tank.

[0012] (6) The flash product obtained in step (5) is fed into a distillation column. The top of the column is separated to obtain elastomer raw material, which is used to enter the elastomer process to produce elastomer products. The bottom of the column is separated to obtain curing agent raw material, which is used to enter the curing agent process to produce methyltetrahydrophthalic anhydride products.

[0013] The temperature of the thermal polymerization reaction in step (1) is 120-190℃, the operating pressure is 1.0-3.0 MPaG, the residence time is 1-3h, and the temperature is maintained by an external circulation heat exchanger. The circulation heat exchanger transports materials through a first delivery pump, simultaneously performing material mixing and heat extraction, thereby achieving rapid material mixing and heat extraction, and maintaining the reaction temperature within a certain range.

[0014] The polymerization reactor in step (1) is a polymerization kettle or a tubular reactor.

[0015] In step (2), the temperature at the top of the separation tower is controlled at 30-50℃, the temperature at the bottom of the tower is controlled at 80-100℃, the system pressure is controlled at 0.01-0.05 MPaG, and the reflux ratio is controlled at 2-4.

[0016] In step (3), the temperature of the second flash tank is controlled at 80-100℃ and the system pressure is -0.05-0.1MPaG.

[0017] The refined DCPD hydrogenation resin raw material in step (3) contains 10-30 wt% polydicyclopentadiene (TDCPD), 60-80% DCPD, and 3-5% norbornene. The TDCPD and norbornene components in this polymer raw material can provide a monoolefin composition for the DCPD hydrogenation resin polymerization raw material, thereby achieving the purpose of controlling the softening point of the DCPD hydrogenation resin product.

[0018] In step (4), the temperature at the top of the extraction tower T2 is controlled at 40-50℃, the temperature at the bottom of the tower is controlled at 110-120℃, the system pressure is 0.01-0.04MPaG, the reflux ratio is 4-6, and the extractant / feed ratio is 5:1.

[0019] The extractant in step (5) is N,N-dimethylformamide or acetonitrile.

[0020] In step (5), the temperature of the first flash tank is controlled at 150-170℃ and the system pressure is 0.02-0.04MPaG.

[0021] In step (6), the temperature at the top of the refining column is controlled at 40-50℃, the temperature at the bottom of the column is controlled at 80-90℃, the system pressure is 0.04-0.06MPaG, and the reflux ratio is 15-17.

[0022] The elastomer raw material in step (6) contains ≥99.3wt% isoprene and <15ppm cyclopentadiene.

[0023] The curing agent raw material in step (6) contains 10-25 wt% isoprene and 25-45 wt% trans-isoprene. This curing agent raw material is a mixture of isoprene and isoprene, which can effectively lower the freezing point of methyltetrahydrophthalic anhydride, preventing it from crystallizing at -15°C. At the same time, it can also achieve the purpose of lowering the glass transition temperature of epoxy resin.

[0024] The refined DCPD hydrogenated resin raw material undergoes a thermal polymerization reaction at 200-300℃, followed by a hydrogenation reaction to produce DCPD hydrogenated resin; the curing agent raw material undergoes a polymerization reaction with maleic anhydride at 50-75℃ to produce methyltetrahydrophthalic anhydride product; the elastomer raw material undergoes an anionic polymerization reaction with styrene to produce SIS thermoplastic elastomer product; the heavy components undergo a polymerization reaction at 200-300℃ to produce dark-colored thermopolymer resin.

[0025] Beneficial effects

[0026] (1) The present invention includes a method for utilizing various dienes; the method is simple to operate, uses ethylene cracking C5 as raw material, has low cost, does not require high equipment, and is suitable for large-scale production.

[0027] (2) The process flow of this invention is short, and the purity requirements of each material are not high. The DCPD hydrogenation resin raw material and the curing agent raw material are mixed components. The purity of the elastomer raw material isoprene can be adjusted according to the amount of material taken out from the bottom of the tower, without affecting the utilization of the final material. This method has low separation cost and effectively utilizes each diene component.

[0028] (3) The DCPD hydrogenation resin raw material of the present invention contains TDCPD and norbornene components, which can provide a monoolefin composition for the DCPD hydrogenation resin polymerization raw material and can achieve the purpose of controlling the softening point of DCPD hydrogenation resin products.

[0029] (4) The curing agent raw material of the present invention is a mixture of isoprene and isoprene, which can effectively reduce the freezing point of methyltetrahydrophthalic anhydride so that it will not crystallize at -15°C. At the same time, the curing agent product can achieve the purpose of reducing the glass transition temperature of epoxy resin.

[0030] (5) The present invention uses high-temperature polymerization to polymerize the alkyne components in ethylene cracking C5 to produce heavy components for removal, avoiding the removal of alkyne components in ethylene cracking C5 by high reflux ratio distillation separation, which can greatly reduce the production cost of the equipment; the removed heavy components can also be used to enter the thermal polymer resin process to produce dark thermal polymer resin. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the process flow of the present invention. Detailed Implementation

[0032] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0033] Table 1 below shows the specifications of the ethylene cracking C5 used in each embodiment.

[0034] Table 1

[0035]

[0036]

[0037] The process flow of each embodiment is as follows: Figure 1 As shown.

[0038] Example 1

[0039] (1) The ethylene cracking C5 F1 is fed into the polymerization reactor R1. The material in the polymerization reactor R1 is transported to the external circulation cooler E1 by the first transfer pump P1. The material is heated by circulating water. The reaction temperature is controlled at 150℃, the system operating pressure is 1.7MPaG, and the residence time is 2h.

[0040] (2) The mixture F2 generated after the thermal polymerization reaction is fed into the separation tower T1 for separation. The temperature at the top of the separation tower T1 is controlled at 45°C, the temperature at the bottom of the tower is 95°C, the system pressure is 0.045 MPaG, and the reflux ratio is 3. The top of the tower yields the separation product F3 (a mixture of isoprene, isoprene, monoolefins and alkanes); the bottom of the tower yields the crude dicyclopentadiene DCPD hydrogenation resin polymerization raw material F4, which contains norbornene, dicyclopentadiene (DCPD), polydicyclopentadiene (TDCPD) and heavy components.

[0041] (3) The crude dicyclopentadiene DCPD hydrogenation resin polymerization raw material F4 is fed into the second flash tank V2 for deweight separation. The temperature of the second flash tank V2 is controlled at 90℃ and the system pressure is -0.099MPaG. The refined DCPD hydrogenation resin raw material F11 obtained from the top of the tank is sent to the hydrogenation resin process to produce DCPD hydrogenation resin F14, and the heavy component F12 obtained from the bottom of the tank is sent to the next thermal polymerization resin process to produce dark thermal polymerization resin F15.

[0042] (4) The separated product F3 obtained in step (2) is fed into the extraction tower T2 (the temperature at the top of the tower is controlled at 48°C, the temperature at the bottom of the tower is 118°C, the system pressure is 0.038 MPaG, the reflux ratio is 5, and the ratio of extractant DMF to feed is 5:1). The remaining C5 raw material F5 is obtained at the top of the tower, and the extraction product F7 (including DMF, isoprene, and isoprene) is obtained at the bottom of the tower.

[0043] (5) The extraction product F7 is fed into the first flash tank V1 to separate the extraction solvent DMF, isoprene and isoprene. The temperature of the first flash tank V1 is 160°C and the system pressure is 0.03 MPaG. The flash product F8 is obtained at the top of the flash tank and the extraction solvent DMF F6 is collected from the bottom of the flash tank and returned to the extraction tower T2 through the second transfer pump P2.

[0044] (6) The flash product F8 was fed into the refining column T3. The top temperature of the refining column T3 was controlled at 46℃, the bottom temperature at 84℃, the system pressure at 0.051 MPaG, and the reflux ratio at 16. Elastomer raw material F9 was obtained from the top of the column and used in the elastomer process to produce elastomer product F13; curing agent raw material F10 was obtained from the bottom of the column and used in the curing agent process to produce methyltetrahydrophthalic anhydride product F16. The experimental results are shown in Table 3.

[0045] The refined DCPD hydrogenated resin raw material F11 was mixed with trimethylbenzene and subjected to thermal polymerization at 230℃ and 0.5MPaG. After 15 hours of reaction, the trimethylbenzene was removed from the material under reduced pressure. The polymer solution was mixed with hydrogenated white oil and subjected to hydrogenation reactor at a hydrogenation pressure of 15MPa and a hydrogenation temperature of 280℃. After hydrogenation, the solvent was removed to obtain DCPD hydrogenated resin with color number 0# and softening point of 100℃.

[0046] The curing agent raw material F10 was mixed with maleic anhydride and reacted at 60℃ and 0.2MPaG for 3 hours. The unreacted C5 material was then mixed with polyphosphoric acid and reacted at 190℃ and 0.1MPa for 2 hours to obtain the isomerized material. The heavy components were removed by flash evaporation to obtain the methyltetrahydrophthalic anhydride product with color number 20.

[0047] Elastomer raw material F9 was mixed with styrene and cyclohexane, and reacted for 20 min at 80 °C and 0.34 MPaG under the action of initiator n-butylaluminum. Styrene was then added to continue the reaction. The resulting SIS elastomer polymer liquid was then subjected to cyclohexane solvent removal to obtain SIS elastomer with a yellow index of 1 and a melt mass flow rate of 18 g / 10 min (200 °C / 5 kg).

[0048] The heavy component F12 was reacted at 250℃ and 0.1MPaG for 6 hours. The resulting polymer solution was desolventized by flash evaporation to obtain a dark-colored thermopolymer resin with a softening point of 110℃ and a color number of 18.

[0049] Example 2

[0050] The difference from Example 1 is that in step (1), the reaction temperature was controlled at 160°C, the system operating pressure was 1.9 MPa, and the residence time was 2 hours. The experimental results are shown in Table 3.

[0051] Example 3

[0052] The difference from Example 1 is that in step (1), the reaction temperature was controlled at 170°C, the system operating pressure was 2.1 MPa, and the residence time was 2 hours. The experimental results are shown in Table 3.

[0053] Example 4

[0054] The difference from Example 1 is that in step (1), the reaction temperature was controlled at 160°C, the system operating pressure was 1.9 MPa, and the residence time was 3 hours. The experimental results are shown in Table 3.

[0055] Example 5

[0056] The difference from Example 4 is that the reflux ratio of the purification tower T3 in step (6) is 20. The experimental results are shown in Table 3.

[0057] Example 6

[0058] The difference from Example 5 is that in step (1), the reaction temperature was controlled at 190°C, the system operating pressure was 2.5 MPa, and the residence time was 1 h. The experimental results are shown in Table 3.

[0059] Example 7

[0060] The difference from Example 6 is that the reflux ratio of the purification tower T3 in step (6) is 18. The experimental results are shown in Table 3.

[0061] Table 2 Composition of Remaining C5 Raw Materials

[0062] Serial Number composition Content, wt% 1 Trimethylbutene 0.0088 2 1,4-Pentadiene 2.3059 3 2-Butyne 0.0001 4 isopentane 12.2452 5 1-Pentene 8.3233 6 2-Methyl-1-butene 14.8273 7 Isopentyne 0 8 Isoprene 1.0008 9 n-Pentane 43.5863 10 2-Transpentene 6.2705 11 2-cispentene 4.0534 12 2-Methyl-2-butene 7.3236 13 cyclopentene 0.0007 14 cyclopentane 0.0533

[0063] Table 3 Results of each embodiment

[0064]

Claims

1. A method for the comprehensive utilization of C5 from ethylene cracking, comprising the following steps: (1) Ethylene cracking C5 (F1) is fed into a polymerization reactor (R1) and the alkyne component and cyclopentadiene are polymerized through a thermal polymerization reaction to produce a mixture (F2); (2) The mixture (F2) obtained in step (1) is fed into the separation tower (T1) for separation. The crude dicyclopentadiene DCPD hydrogenation resin polymerization raw material (F4) is obtained at the bottom of the tower, and the separation product (F3) is obtained at the top of the tower. (3) The crude DCPD hydrogenation resin polymerization raw material (F4) obtained in step (2) is fed into the second flash tank (V2) for deweight separation. The refined DCPD hydrogenation resin raw material (F11) obtained from the top of the tank is used to enter the hydrogenation resin process to produce DCPD hydrogenation resin (F14); the heavy component (F12) obtained from the bottom of the tank is used to enter the thermopolymerization resin process to produce dark thermopolymerization resin (F15). (4) The separation product (F3) obtained in step (2) is fed into the extraction tower (T2). The remaining C5 raw material (F5) is separated at the top of the tower, and the extraction product (F7) is separated at the bottom of the tower. (5) The extraction product (F7) obtained in step (4) is sent to the first flash tank (V1), the extractant (F6) is separated at the bottom of the tank and returned to the extraction tower (T2) for reuse, and the flash product (F8) is separated at the top of the tank. (6) The flash product (F8) obtained in step (5) is fed into a distillation column (T3). The top of the column is separated to obtain elastomer raw material (F9), which is used to enter the elastomer process to produce elastomer products (F13). The bottom of the column is separated to obtain curing agent raw material (F10), which is used to enter the curing agent process to produce methyltetrahydrophthalic anhydride products (F16).

2. The method according to claim 1, characterized in that: The temperature of the thermal polymerization reaction in step (1) is 120-190℃, the operating pressure is 1.0-3.0MPaG, the residence time is 1-3h, and the temperature is maintained by an external circulation heat exchanger (E1).

3. The method according to claim 1, characterized in that: The polymerization reactor (R1) in step (1) is a polymerization kettle or a tubular reactor.

4. The method according to claim 1, characterized in that: The refined DCPD hydrogenated resin raw material (F11) in step (3) has a polydicyclopentadiene TDCPD content of 10-30 wt%, a DCPD content of 60-80%, and a norbornene content of 3-5%.

5. The method according to claim 1, characterized in that: The extractant (F6) in step (5) is N,N-dimethylformamide or acetonitrile.

6. The method according to claim 1, characterized in that: The isoprene content in the elastomer raw material (F9) in step (6) is ≥99.3wt%, and the cyclopentadiene content is <15ppm.

7. The method according to claim 1, characterized in that: The curing agent raw material (F10) in step (6) contains 10-25 wt% isoprene and 25-45 wt% trans-isoprene.

8. The method according to claim 1, characterized in that: The refined DCPD hydrogenated resin raw material (F11) undergoes a thermal polymerization reaction at 200-300℃, followed by a hydrogenation reaction to produce DCPD hydrogenated resin (F14); the curing agent raw material (F10) undergoes a polymerization reaction with maleic anhydride at 50-75℃ to produce methyltetrahydrophthalic anhydride product (F16); the elastomer raw material (F9) undergoes anionic polymerization reaction with styrene to produce SIS thermoplastic elastomer product (F13); and the heavy component (F12) undergoes a polymerization reaction at 200-300℃ to produce dark-colored thermopolymer resin (F15).

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