Anti-alkylation reaction process for reducing energy consumption of benzene tower

Abstract

The invention discloses an anti-alkylation reaction process capable of reducing energy consumption of a benzene tower, which comprises the following steps: in an anti-alkylation reaction system, diisopropylbenzene and triisopropylbenzene generated in an alkylation reactor are subjected to an anti-alkylation reaction with benzene in the anti-alkylation reactor to generate isopropylbenzene, and the feeding weight ratio of the benzene to polyisopropylbenzene introduced into the anti-alkylation reactor is adjusted to 1.14: 1-1.18: 1; benzene and polyisopropylbenzene form a mixed solution, the mixed solution in the anti-alkylation reactor is heated to 179-181 DEG C, the back pressure of an outlet of the anti-alkylation reactor is controlled to be 2.0 MPa, and the weight ratio of benzene in an outlet material of the anti-alkylation reactor is controlled to be 35-38%. According to the anti-alkylation reaction process disclosed by the invention, the energy consumption of the benzene tower can be greatly reduced; meanwhile, the extraction of heavy aromatics is also reduced.

Description

Technical Field

[0001] The invention relates to a transalkylation reaction process for reducing the energy consumption of a benzene tower, and belongs to the technical field of chemical industry. Background Art

[0002] The cumene unit uses benzene and propylene as the main raw materials, and adopts the American Mobil / Badger cumene technology to produce cumene by the reaction of benzene and propylene. During the reaction, polyisopropylbenzene (diisopropylbenzene and triisopropylbenzene) will also be produced as recyclable impurities. Benzene and polyisopropylbenzene are transalkylated in the transalkylation reactor to obtain cumene. Benzene and cumene are separated and recovered in the benzene tower.

[0003] The current benzene tower has high energy consumption and requires a large amount of desalted water to wash the gas phase of the benzene tower to ensure the removal of organic acids entrained in the gas phase, which generates a large amount of wastewater and has high production costs. Summary of the invention

[0004] In order to solve at least one problem existing in the above-mentioned prior art, the present invention provides a transalkylation reaction process for reducing the energy consumption of the benzene tower, which can greatly reduce the energy consumption of the benzene tower; at the same time, it also reduces the production of heavy aromatics.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a transalkylation reaction process for reducing the energy consumption of a benzene tower, the isopropylbenzene process preparation comprises a raw material processing system, a alkylation reaction system, a transalkylation reaction system and a finished product refining system, wherein the transalkylation reaction system: diisopropylbenzene and triisopropylbenzene generated in a alkylation reactor will undergo a transalkylation reaction with benzene in a transalkylation reactor to generate isopropylbenzene, the feed weight ratio of benzene to polyisopropylbenzene introduced into the transalkylation reactor is adjusted to 1.14:~1.18, benzene and polyisopropylbenzene form a mixed liquid, the mixed liquid in the transalkylation reactor is heated to a temperature of 179~181°C, the back pressure at the outlet of the transalkylation reactor is controlled at 2.0MPa, and the weight proportion of benzene in the outlet material of the transalkylation liquid is controlled to be 35~38%.

[0006] Preferably, the mixed liquid in the transalkylation reactor is heated to a temperature of 180°C.

[0007] Preferably, the weight proportion of benzene in the outlet material of the dehydrocarbonation liquid is controlled to be 35-37%.

[0008] Preferably, the feed weight ratio of benzene to polyisopropylbenzene in the transalkylation reactor is 1.16:1 to 1.165:1.

[0009] Preferably, the feed weight ratio of benzene to polyisopropylbenzene to the transalkylation reactor is 1.165:1.

[0010] Preferably, the feed weight ratio of benzene to polyisopropylbenzene to the transalkylation reactor is 1.16:1.

[0011] Preferably, the weight proportion of benzene in the outlet material of the dehydrocarbonation liquid is controlled to be 36.5%.

[0012] Preferably, the weight proportion of benzene in the outlet material of the dehydrocarbonation liquid is controlled to be 36.6%.

[0013] The beneficial effects of the present invention are as follows: by adjusting the feed ratio of benzene and polyisopropylbenzene introduced into the transalkylation reactor and controlling the benzene ratio of the transalkylation liquid outlet material, the energy consumption of the benzene tower can be greatly reduced; at the same time, the production of heavy aromatics can also be reduced; compared with the original process consuming 13.4 t / h of high-pressure steam, the high-pressure steam usage flow rate of the benzene tower of the present invention can be reduced to 9.66 t / h; compared with the original process consuming 241.2 kg / h of water replenishment, the water replenishment of the benzene tower of the present invention can be reduced to 28.5 kg / h; compared with the original process producing 209.2 kg / h of heavy aromatics, the heavy aromatics of the present invention can be reduced to 161.3 kg / h. DETAILED DESCRIPTION

[0014] The following is a clear and complete description of the technical solutions in the implementation of the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. If the specific conditions are not specified in the embodiments, they are carried out according to the normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents, instruments, and components used, they are all conventional products that can be purchased commercially.

[0015] The cumene preparation process of the present invention includes a raw material processing system, an alkylation reaction system, a reverse alkylation reaction system, and a finished product refining system:

[0016] (1) Raw material processing system: fresh benzene and fresh propylene are pre-treated by upstream devices equipped with a distillation tower and a dryer, respectively, to remove impurities in the fresh benzene and fresh propylene that are poisonous to the catalyst;

[0017] (2) Hydrocarbonation reaction system: a mixture of pretreated propylene and benzene is introduced into the top of the hydrocarbonation reactor so that the total molar ratio of benzene to propylene is 2:1. The propylene entering the reactor flows downward through the catalyst bed and enters between the catalyst beds in four stages; the propylene in the first stage is mixed with benzene and circulating hydrocarbonation liquid and then enters the first stage catalyst bed for reaction; the propylene in the second, third and fourth stages is mixed with the cooled circulating hydrocarbonation liquid and then enters the catalyst beds of each stage for reaction. The hydrocarbonation liquid circulation ratio of the hydrocarbonation reactor is controlled to be 1:22.2, and the back pressure at the reactor outlet of the hydrocarbonation reactor is controlled to be 2.0 MPa;

[0018] (3) Dehydrogenation reaction system: The diisopropylbenzene and triisopropylbenzene generated in the dehydrogenation reactor will undergo dehydrogenation reaction with benzene in the dehydrogenation reactor to generate isopropylbenzene. The feed ratio of benzene and polyisopropylbenzene introduced into the dehydrogenation reactor, the temperature of the mixed liquid in the dehydrogenation reactor, and the back pressure at the outlet of the dehydrogenation reactor are adjusted; and the benzene ratio of the dehydrogenation liquid outlet material is controlled.

[0019] (4) Finished product refining system:

[0020] (4.1) Benzene tower: The unreacted benzene in the hydrocarbonation liquid and the unreacted benzene in the dehydrogenation liquid are introduced into the benzene tower and heated by steam in the reboiler of the benzene tower kettle; the vapor of the top material is condensed in the condenser at the top of the benzene tower, and the recovered benzene product is used as the side-line fraction. It enters the dry benzene tank from the side-line discharge plate for drying, and is then sent to the benzene secondary pretreatment unit by the dry benzene circulation pump for further pretreatment, and then enters the hydrocarbonation reactor and the dehydrogenation reactor; the isopropylbenzene, polyisopropylbenzene and other heavy components at the bottom of the benzene tower are transported by the bottom pump to the isopropylbenzene tower; the discharge flow rate at the bottom of the benzene tower is regulated by the liquid level at the bottom of the tower; the dry benzene reflux liquid is sent back to the lower part of the tower (below the side-line discharge plate) by the dry benzene circulation pump; fresh benzene is sent to the benzene primary pretreatment unit by the benzene delivery pump of the benzene feed buffer tank for pretreatment and then enters the benzene tower for dehydration. The amount of fresh benzene added is determined by the liquid level of the dry benzene tank, and then enters from the top of the benzene tower.

[0021] (4.2) Isopropylbenzene Tower: The isopropylbenzene, polyisopropylbenzene and other heavy components at the bottom of the benzene tower are pumped down to the isopropylbenzene tower by the bottom pump and enter the reboiler of the isopropylbenzene tower kettle. The vapor of the material at the top of the isopropylbenzene tower is condensed in the top condenser. The isopropylbenzene product is first cooled in the (isopropylbenzene product / circulating benzene) heat exchanger and then cooled in the isopropylbenzene finished product cooler. The isopropylbenzene product is recovered in the reflux tank of the isopropylbenzene tower and then transported from the tower side to the outside through the isopropylbenzene tower product pump. Diisopropylbenzene and heavy components are recovered at the bottom of the isopropylbenzene tower.

[0022] (4.3) Polyisopropylbenzene tower: The polyisopropylbenzene (PIB) collected from the side of the PIB tower enters the dehydrogenation reactor to undergo dehydrogenation reaction and is converted into cumene; the material vapor entering the top of the tower is condensed in the air cooler at the top of the tower and flows into the reflux tank of the PIB tower for collection, and the light components in the collected liquid are separated. The light components are then sent to the heavy aromatics tank after being cooled by the reflux pump of the PIB tower through the residual liquid and aromatics cooler; the residual liquid at the bottom of the PIB tower is pumped out by the kettle pump of the PIB tower under direct flow regulation, and is sent to the heavy aromatics tank after being cooled by the residual liquid and aromatics cooler.

[0023] Example 1

[0024] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0025] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0026] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 13.67 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180°C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 37%;

[0027] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0028] Example 2

[0029] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0030] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0031] Dehydrogenation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrogenation reactor will undergo dehydrogenation reaction with benzene in the dehydrogenation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrogenation reactor is adjusted to 13.67 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrogenation reactor is heated to a temperature of 180° C. The back pressure at the outlet of the dehydrogenation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrogenation liquid outlet material is controlled to be 36%;

[0032] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0033] Example 3

[0034] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0035] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0036] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 13.67 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180° C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 38%;

[0037] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0038] Example 4

[0039] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0040] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0041] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 13.67 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180°C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 35%;

[0042] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0043] Example 5

[0044] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0045] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0046] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 13.67 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180° C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 36.5%;

[0047] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0048] Example 6

[0049] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0050] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0051] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene and polyisopropylbenzene into the dehydrocarbonation reactor is adjusted to 13.78 t / h and 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180° C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 36.5%;

[0052] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0053] Example 7

[0054] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0055] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0056] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 13.90 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180° C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 36.5%;

[0057] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0058] Example 8

[0059] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0060] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0061] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 13.55 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180° C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 36.5%;

[0062] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0063] Example 9

[0064] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0065] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0066] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 13.43 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180° C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 36.5%;

[0067] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0068] Example 10

[0069] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0070] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0071] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 13.67 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 181° C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 36.5%;

[0072] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0073] Embodiment 11

[0074] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0075] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0076] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 13.67 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 179° C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 36.5%;

[0077] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0078] Example 12

[0079] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0080] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0081] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 13.72 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180° C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 36.5%;

[0082] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0083] Comparative Example 1

[0084] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0085] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0086] Dehydrogenation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrogenation reactor will undergo dehydrogenation reaction with benzene in the dehydrogenation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrogenation reactor is adjusted to 13.67 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrogenation reactor is heated to a temperature of 180° C. The back pressure at the outlet of the dehydrogenation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrogenation liquid outlet material is controlled to be 38.5%;

[0087] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0088] Comparative Example 2

[0089] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0090] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0091] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 13.67 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180° C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 39%;

[0092] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0093] Comparative Example 3

[0094] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0095] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0096] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 13.67 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180° C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 34.5%;

[0097] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0098] Comparative Example 4

[0099] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0100] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0101] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 13.67 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180°C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 34%;

[0102] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0103] Comparative Example 5

[0104] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0105] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0106] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 13.37 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180° C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 36.5%;

[0107] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0108] Comparative Example 6

[0109] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0110] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0111] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 12.97 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180° C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 36.5%;

[0112] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0113] Comparative Example 7

[0114] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0115] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0116] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 14.02 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180°C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 39%;

[0117] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0118] Comparative Example 8

[0119] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0120] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0121] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 14.14 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180°C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 39%;

[0122] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0123] Comparative Example 9

[0124] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0125] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0126] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 13.67 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180°C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 31%;

[0127] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0128] Comparative Example 10

[0129] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0130] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0131] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 13.67 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 180°C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 44%;

[0132] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0133] Comparative Example 11

[0134] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0135] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0136] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene and polyisopropylbenzene into the dehydrocarbonation reactor is adjusted to 11.78 t / h and 11.78 t / h, and benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 188°C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 44%;

[0137] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0138] Comparative Example 12

[0139] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0140] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0141] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene and polyisopropylbenzene into the dehydrocarbonation reactor is adjusted to 11.78 t / h and 11.78 t / h, and benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 188°C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 31%;

[0142] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0143] Comparative Example 13

[0144] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0145] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0146] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 14.14 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 177°C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 44%;

[0147] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0148] Comparative Example 14

[0149] A transalkylation reaction process for reducing energy consumption of benzene tower:

[0150] The three parts of the raw material processing system, the alkylation reaction system and the finished product refining system are prepared according to the above-mentioned existing cumene process;

[0151] Dehydrocarbonation reaction system: diisopropylbenzene and triisopropylbenzene generated in the dehydrocarbonation reactor will undergo dehydrocarbonation reaction with benzene in the dehydrocarbonation reactor to generate isopropylbenzene. The feed rate of benzene entering the dehydrocarbonation reactor is adjusted to 14.14 t / h and the feed rate of polyisopropylbenzene is adjusted to 11.78 t / h. Benzene and polyisopropylbenzene form a mixed liquid. The mixed liquid in the dehydrocarbonation reactor is heated to a temperature of 177°C. The back pressure at the outlet of the dehydrocarbonation reactor is controlled at 2.0 MPa, and the weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 44%;

[0152] The amount of high-pressure steam used in the benzene tower and the amount of water added to the benzene tower reflux tank were recorded. The results are shown in Table 1.

[0153] Table 1 Experimental results of Examples 1 to 12 and Comparative Examples 1 to 14

[0154]

[0155] As can be seen from the above table, in the transalkylation reaction system, the benzene entering the transalkylation reactor is mixed with the circulating liquid discharged from the polyisopropylbenzene tower, and the resulting mixed liquid is heated to 179-181°C. The back pressure regulating valve of the transalkylation reactor is controlled at 2.0 MPa in the entire reactor to inhibit the vaporization of the reaction liquid, ensure that the optimal feed weight distribution of benzene and polyisopropylbenzene entering the transalkylation reactor is 1.14:1-1.18:1, and control the outlet material of the transalkylation liquid. The weight proportion of medium benzene is 35-38%, which ensures that the conversion rate of the dealkylation reactor is maintained at about 50%. At the same time, the high-pressure steam flow rate of the benzene tower is reduced from the original 13.43t / h to 9.66t / h, and the water replenishment volume of the benzene tower reflux tank is reduced from the original 241.2kg / h to 28.5kg / h, and the heavy aromatics output is reduced from 209.2kg / h to 161.3kg / h, which greatly reduces the energy consumption of the benzene tower and reduces by-products.

[0156] The optimal feed weight distribution of benzene and polyisopropylbenzene is maintained at 1.14:1 to 1.18:1. When the benzene ratio of the dehydrogenation liquid outlet material is too high, it means that the conversion rate of the dehydrogenation reactor is reduced. Although the by-products produced by the reaction are reduced, the circulating benzene flow in the benzene tower will be increased, and the high-pressure steam consumption of the benzene tower will increase, which is not conducive to energy saving of the benzene tower; when the benzene ratio of the dehydrogenation liquid outlet material is low, it means that the conversion rate of the dehydrogenation reactor is increased, but with the increase in the content of by-products, the content of organic acids and light components in the dehydrogenation liquid will increase, and it is necessary to increase the desalted water in the benzene tower reflux tank to remove the organic acids in the dehydrogenation reactor, which increases the amount of water replenishment and is not conducive to energy saving of the benzene tower.

[0157] In addition, the increase in the conversion rate in the dehydrogenation means an increase in side reactions. More polyisobenzenes are prone to functional group breakage during the recombination process to form small molecular compounds, that is, more non-condensable gases are produced. The gas phase will be discharged to the phenol acetone device for tail gas catalytic oxidation treatment. The increased gas phase will lead to excessive temperature rise in the catalytic oxidation reactor (CO furnace), which will reduce product output and increase production costs.

[0158] In summary, in Examples 1 to 12, in the transalkylation reaction system, the back pressure regulating valve of the transalkylation reactor is controlled at 2.0 MPa throughout the reactor, and the temperature of the mixed liquid of benzene and polyisopropylbenzenes is maintained at 179 to 181°C; the optimal feed weight distribution of benzene and polyisopropylbenzenes in the transalkylation reactor is 1.14:1 to 1.18:1, and the weight proportion of benzene in the outlet material of the transalkylation liquid is controlled to be 35 to 38%, the energy consumption of the benzene tower and the recovery of heavy aromatics are greatly reduced, and the effect is better; better effect: the temperature of the mixed liquid of benzene and polyisopropylbenzenes is maintained at 180°C; the optimal feed weight distribution of benzene and polyisopropylbenzenes in the transalkylation reactor is 1.16:1 to 1.6 5:1, and the weight proportion of benzene in the outlet material of the dehydrogenation liquid is controlled to be 35-38%, the energy consumption of the benzene tower and the production of heavy aromatics are greatly reduced; secondly, better effect: keep the temperature of the mixed liquid of benzene and polyisopropylbenzenes at 180°C; the optimal feed weight distribution of benzene and polyisopropylbenzenes in the dehydrogenation reactor is 1.16:1-1.165:1, and the weight proportion of benzene in the outlet material of the dehydrogenation liquid is controlled to be 36.5-36.6%; the best effect, keep the temperature of the mixed liquid of benzene and polyisopropylbenzenes at 180°C; the optimal feed weight distribution of benzene and polyisopropylbenzenes in the dehydrogenation reactor is 1.165:1, and the weight proportion of benzene in the outlet material of the dehydrogenation liquid is controlled to be 36.5%.

[0159] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit and essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0160] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A transalkylation reaction process for reducing the energy consumption of a benzene tower, wherein the process for preparing cumene comprises a raw material processing system, an alkylation reaction system, a transalkylation reaction system and a finished product refining system, wherein: Dehydrogenation reaction system: the diisopropylbenzene and triisopropylbenzene generated in the dehydrogenation reactor will undergo dehydrogenation reaction with benzene in the dehydrogenation reactor to generate cumene. The feed weight ratio of benzene to polyisopropylbenzenes entering the dehydrogenation reactor is adjusted to 1.14:~1.

18. Benzene and polyisopropylbenzenes form a mixed liquid. The mixed liquid in the dehydrogenation reactor is heated to a temperature of 179~181°C. The back pressure at the outlet of the dehydrogenation reactor is controlled at 2.0MPa, and the weight proportion of benzene in the dehydrogenation liquid outlet material is controlled to be 35~38%.

2. A transalkylation reaction process for reducing the energy consumption of a benzene tower according to claim 1, characterized in that: The mixed liquid in the dehydrogenation reactor is heated to a temperature of 180°C.

3. A transalkylation reaction process for reducing the energy consumption of a benzene tower according to claim 2, characterized in that: The weight proportion of benzene in the dehydrocarbonation liquid outlet material is controlled to be 35-37%.

4. A transalkylation reaction process for reducing the energy consumption of a benzene tower according to claim 3, characterized in that: The feed weight ratio of benzene to polyisopropylbenzene in the transalkylation reactor is 1.16:1 to 1.165:

1.

5. A transalkylation reaction process for reducing the energy consumption of a benzene tower according to claim 3, characterized in that: The feed weight ratio of benzene to polyisopropylbenzene to the transalkylation reactor was 1.165:

1.

6. A transalkylation reaction process for reducing the energy consumption of a benzene tower according to claim 3, characterized in that: The feed weight ratio of benzene to polyisopropylbenzene to the transalkylation reactor was 1.16:

1.

7. A transalkylation reaction process for reducing the energy consumption of a benzene tower according to any one of claim 6, characterized in that: The weight proportion of benzene in the outlet material of the dehydrocarbonation liquid is controlled to be 36.5%.

8. A transalkylation reaction process for reducing the energy consumption of a benzene tower according to any one of claim 5, characterized in that: The weight proportion of benzene in the outlet material of the dehydrocarbonation liquid is controlled to be 36.6%.

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