CN111393249B - Method for reducing ethylbenzene loss and energy consumption of ethylbenzene tower in ethylbenzene synthesis process - Google Patents
Method for reducing ethylbenzene loss and energy consumption of ethylbenzene tower in ethylbenzene synthesis process Download PDFInfo
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- CN111393249B CN111393249B CN202010288781.4A CN202010288781A CN111393249B CN 111393249 B CN111393249 B CN 111393249B CN 202010288781 A CN202010288781 A CN 202010288781A CN 111393249 B CN111393249 B CN 111393249B
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- YNQLUTRBYVCPMQ-UHFFFAOYSA-N Ethylbenzene Chemical compound CCC1=CC=CC=C1 YNQLUTRBYVCPMQ-UHFFFAOYSA-N 0.000 title claims abstract description 465
- 238000000034 method Methods 0.000 title claims abstract description 32
- 230000015572 biosynthetic process Effects 0.000 title claims abstract description 20
- 238000005265 energy consumption Methods 0.000 title claims abstract description 20
- 238000003786 synthesis reaction Methods 0.000 title claims abstract description 20
- 239000000463 material Substances 0.000 claims abstract description 45
- 238000010992 reflux Methods 0.000 claims abstract description 41
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 claims description 123
- ODLMAHJVESYWTB-UHFFFAOYSA-N propylbenzene Chemical compound CCCC1=CC=CC=C1 ODLMAHJVESYWTB-UHFFFAOYSA-N 0.000 claims description 48
- 238000000926 separation method Methods 0.000 claims description 42
- 239000000047 product Substances 0.000 claims description 35
- KVNYFPKFSJIPBJ-UHFFFAOYSA-N 1,2-diethylbenzene Chemical compound CCC1=CC=CC=C1CC KVNYFPKFSJIPBJ-UHFFFAOYSA-N 0.000 claims description 34
- 238000005804 alkylation reaction Methods 0.000 claims description 28
- 239000007788 liquid Substances 0.000 claims description 23
- 238000006243 chemical reaction Methods 0.000 claims description 22
- 238000010521 absorption reaction Methods 0.000 claims description 17
- 230000029936 alkylation Effects 0.000 claims description 13
- 239000006227 byproduct Substances 0.000 claims description 12
- 239000000376 reactant Substances 0.000 claims description 3
- 230000002194 synthesizing effect Effects 0.000 abstract description 7
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 9
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 9
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 6
- 239000005977 Ethylene Substances 0.000 description 6
- OCKPCBLVNKHBMX-UHFFFAOYSA-N butylbenzene Chemical compound CCCCC1=CC=CC=C1 OCKPCBLVNKHBMX-UHFFFAOYSA-N 0.000 description 6
- 238000010586 diagram Methods 0.000 description 6
- 230000002745 absorbent Effects 0.000 description 5
- 239000002250 absorbent Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 238000005406 washing Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 150000001336 alkenes Chemical class 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 238000004523 catalytic cracking Methods 0.000 description 2
- 238000006555 catalytic reaction Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- CRVGTESFCCXCTH-UHFFFAOYSA-N methyl diethanolamine Chemical compound OCCN(C)CCO CRVGTESFCCXCTH-UHFFFAOYSA-N 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 125000000383 tetramethylene group Chemical group [H]C([H])([*:1])C([H])([H])C([H])([H])C([H])([H])[*:2] 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- IAQRGUVFOMOMEM-UHFFFAOYSA-N butene Natural products CC=CC IAQRGUVFOMOMEM-UHFFFAOYSA-N 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 150000005194 ethylbenzenes Chemical class 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/009—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping in combination with chemical reactions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/32—Other features of fractionating columns ; Constructional details of fractionating columns not provided for in groups B01D3/16 - B01D3/30
- B01D3/322—Reboiler specifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/42—Regulation; Control
- B01D3/4205—Reflux ratio control splitter
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/005—Processes comprising at least two steps in series
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/04—Purification; Separation; Use of additives by distillation
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- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Water Supply & Treatment (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention provides a method for reducing ethylbenzene loss and energy consumption of an ethylbenzene tower in an ethylbenzene synthesis process. In the process for synthesizing the ethylbenzene, the overhead reflux ratio of the ethylbenzene tower is reduced, particularly controlled to be 1.80-3.30, the temperature of a tower kettle of the ethylbenzene tower is increased, particularly controlled to be 220-221 ℃, and as a result, on the basis of ensuring the quality of an ethylbenzene product, the ethylbenzene content of materials at the bottom of the ethylbenzene tower can be effectively reduced, the ethylbenzene loss is reduced, and meanwhile, the load of an ethylbenzene product condenser and the load of an ethylbenzene tower bottom reboiler of an ethylbenzene tower unit are reduced, so that the energy consumption of a device is effectively reduced.
Description
Technical Field
The invention relates to the field of chemical industry, in particular to a method for reducing ethylbenzene loss and energy consumption of an ethylbenzene tower in an ethylbenzene synthesis process.
Background
The ethylbenzene plant is a chemical plant for synthesizing ethylbenzene, which uses dry gas from a catalytic cracking unit and petroleum benzene from an aromatics plant as raw materials, and takes ethylbenzene as a main product and toluene, propylbenzene, diethylbenzene and the like as byproducts, as shown in fig. 1, and fig. 1 is a reaction schematic diagram for synthesizing ethylbenzene. The ethylbenzene device mainly comprises raw material treatment, reaction tail gas absorption and separation units.
Specifically, the reaction principle and the process are as follows: the dry gas contains ethylene and a small amount of olefins such as propylene and butylene, and the dry gas and benzene have alkylation reaction under certain operation conditions, as follows:
main reaction:
benzene + ethylene → alkylation → ethylbenzene;
side reaction:
while generating ethylbenzene, the ethylbenzene can continuously react with ethylene to generate diethylbenzene and polyethylbenzene, a small amount of olefins such as propylene and butylene contained in the dry gas can also react with ethylbenzene to generate propylbenzene, butylbenzene and the like.
In the alkylation process, the by-products of diethylbenzene, propylbenzene and butylbenzene can perform anti-alkylation reaction with benzene under certain operation conditions and catalysis to convert into ethylbenzene, so that ethylbenzene loss can be reduced, and product yield can be improved. Therefore, the reaction unit in the ethylbenzene plant includes an alkylation unit and an anti-alkylation unit, the general structure of the ethylbenzene plant is shown in fig. 2, and fig. 2 is a simplified schematic diagram of the ethylbenzene plant. The process flow is roughly as follows: after the dry gas and benzene react, the obtained mixed material rich in ethylbenzene enters subsequent separation equipment such as a benzene tower and an ethylbenzene tower, and main products and various byproducts are sequentially separated.
At present, the quality index of an ethylbenzene product extracted from the top of an ethylbenzene tower is often paid much attention in an ethylbenzene device, and although the stability of the properties of the ethylbenzene product at the top of the tower can be ensured in actual operation, the content of ethylbenzene in a material at the bottom of the ethylbenzene tower is higher, the content of ethylbenzene in the material at the bottom of the ethylbenzene tower reaches more than 4% when the control is insufficient, and more than 240 tons of ethylbenzene are lost every year according to 0.74t/h of the material at the bottom of the ethylbenzene tower, so that huge waste is caused. Moreover, in order to control the ethylbenzene separation precision, the overhead pressure of the ethylbenzene tower is controlled to be higher, the product stability is ensured through a large reflux ratio, and meanwhile, the loads of a tower bottom reboiler and an overhead condenser are improved to different degrees, so that energy consumption waste is caused.
Disclosure of Invention
In view of the above, the present invention provides a method for reducing ethylbenzene loss and energy consumption in an ethylbenzene synthesis process. The method provided by the invention can effectively reduce the ethylbenzene loss at the bottom of the ethylbenzene tower and the energy consumption of the ethylbenzene tower on the premise of ensuring the qualified quality of the ethylbenzene product, and improve the benefit of the device.
The invention provides a method for reducing ethylbenzene loss and energy consumption of an ethylbenzene tower in an ethylbenzene synthesis process, which comprises the following steps:
after the dry gas and the benzene react in a reaction unit of the ethylbenzene synthesis device, separating a main product ethylbenzene and a byproduct from the obtained reactant through a separation unit, wherein the ethylbenzene product and a tower bottom material are obtained after the separation treatment of an ethylbenzene tower unit in the separation unit;
in the ethylbenzene tower unit, the temperature of a tower kettle of the ethylbenzene tower is controlled to be 220-221 ℃, and the reflux ratio at the top of the ethylbenzene tower is 1.80-3.30.
Preferably, the overhead reflux ratio of the ethylbenzene column is 2.4 to 3.30.
Preferably, the overhead pressure of the ethylbenzene tower is 80-120 KPa, and the overhead temperature is 158-168 ℃.
Preferably, the ethylbenzene export temperature of the ethylbenzene column unit is 10-40 ℃.
Preferably, the feeding flow rate of the ethylbenzene tower is 5.8-9.5 t/h, the feeding temperature is 243-252 ℃, and the feeding pressure is 155-160 KPa.
Preferably, the pressure of the bottom of the ethylbenzene tower is 145-170 KPa.
Preferably, the reflux temperature of the ethylbenzene column unit is 135-140 ℃.
Preferably, the ethylbenzene column unit comprises:
an ethylbenzene column;
the gas inlet of the steam generator is communicated with the gas outlet at the top of the ethylbenzene tower;
the feed inlet is communicated with the discharge hole of the steam generator;
the liquid inlet of the reflux pump is communicated with the liquid outlet of the reflux tank; a liquid outlet of the reflux pump is respectively communicated with a liquid return port of the ethylbenzene tower and a liquid inlet of the ethylbenzene product condenser;
a tower bottom delivery pump is communicated with a tower bottom discharge hole of the ethylbenzene tower;
and the tower bottom reboiler is communicated with the tower kettle of the ethylbenzene tower.
Preferably, the separation unit comprises:
a benzene column unit;
the feed inlet of the ethylbenzene tower unit is communicated with the discharge outlet of the benzene tower unit;
a propylbenzene tower unit with a feeding hole communicated with the discharge hole of the ethylbenzene tower unit;
and the feeding hole of the diethylbenzene tower unit is communicated with the propylbenzene tower unit.
Preferably, the reaction unit comprises:
an alkylation reactor;
the feeding port of the coarse fractionating tower is communicated with the discharge port of the alkylation reactor;
the gas inlet is communicated with the gas outlet at the top of the rough separation tower;
the feed inlet is communicated with the discharge hole of the absorption tower;
the anti-alkylation reactor is communicated with the benzene tower unit in the separation unit, and the tower bottom discharge port of the coarse separation tower is communicated with the benzene tower unit in the separation unit.
In the process for synthesizing the ethylbenzene, the overhead reflux ratio of the ethylbenzene tower is reduced, specifically controlled to be 1.80-3.30, the temperature of a tower kettle of the ethylbenzene tower is increased, specifically controlled to be 220-221 ℃, and therefore the ethylbenzene content of materials at the bottom of the ethylbenzene tower can be effectively reduced, the ethylbenzene loss is reduced, meanwhile, the ethylbenzene product condenser load and the ethylbenzene reboiler load at the bottom of the ethylbenzene tower of an ethylbenzene tower unit are reduced, and therefore the energy consumption of the device is effectively reduced.
Test results show that the treatment method can reduce the ethylbenzene content in the tower bottom material of the ethylbenzene tower to below 0.5%, reduce the condenser load to above 28% and reduce the reboiler load to above 31% on the basis of ensuring the ethylbenzene content in the tower top material of the ethylbenzene tower to be above 99.8%.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a reaction scheme for the synthesis of ethylbenzene;
FIG. 2 is a simplified schematic of an ethylbenzene plant;
FIG. 3 is a schematic diagram of an ethylbenzene synthesis unit provided by the present invention;
FIG. 4 is a schematic diagram of the structure of an ethylbenzene column unit in accordance with the present invention.
Detailed Description
The invention provides a method for reducing ethylbenzene loss and energy consumption of an ethylbenzene tower in an ethylbenzene synthesis process, which comprises the following steps:
after the dry gas and benzene react in a reaction unit of an ethylbenzene synthesis device, separating a main product ethylbenzene and a byproduct from an obtained reactant through a separation unit, wherein an ethylbenzene product and a tower bottom material are obtained after separation treatment of an ethylbenzene tower unit in the separation unit;
in the ethylbenzene tower unit, the temperature of a tower kettle of the ethylbenzene tower is controlled to be 220-221 ℃, and the reflux ratio at the top of the ethylbenzene tower is 1.80-3.30.
In the present invention, the dry gas is a dry gas from a catalytic cracking apparatus, and contains ethylene and a small amount of olefins such as propylene and butene. In the present invention, before the dry gas is sent to the ethylbenzene device, the dry gas is preferably purified as follows: dry gas is fed from the lower part or the bottom of the water washing tower and is in reverse contact with water at the upper part or the top of the water washing tower for absorption in the water washing tower, so that the concentration of MDEA (methyldiethanolamine) in the dry gas is reduced to below 1 ppm; the dry gas after washing is sent into a propylene absorption tower from the lower part or the bottom of the propylene absorption tower, an absorbent (benzene) is sent from the upper part or the top of the propylene absorption tower, the dry gas and the absorbent are in reverse contact in the propylene absorption tower to absorb the propylene in the dry gas, and the purified dry gas after absorption treatment is discharged from the top of the propylene absorption tower and is sent into an ethylbenzene synthesis device as a raw material.
In the present invention, the benzene is preferably heated before being fed to the ethylbenzene synthesis unit. The heating temperature is preferably 375-385 ℃, and hot benzene obtained by heating is used as a raw material and is sent to an ethylbenzene synthesis device.
In the invention, the ethylbenzene synthesis device comprises a reaction unit and a separation unit. Referring to fig. 3, fig. 3 is a schematic structural diagram of an ethylbenzene synthesis unit provided by the present invention; wherein 1 is a reaction unit, and 2 is a separation unit.
In the present invention, the reaction unit 1 includes:
an alkylation reactor 1a;
a crude separation tower 1b with a feeding hole communicated with a discharge hole of the alkylation reactor;
the gas inlet is communicated with the gas outlet at the top of the rough separation tower;
a reverse alkylation reactor 1d with a feed inlet communicated with a discharge port of the absorption tower;
the anti-alkylation reactor is communicated with the benzene tower unit in the separation unit, and the tower bottom discharge port of the coarse separation tower is communicated with the benzene tower unit in the separation unit.
The operation of the reaction unit 1 is as follows:
(1) The purified dry gas and hot benzene enter an alkylation reactor to carry out alkylation reaction to generate main products of ethylbenzene and byproducts of propylbenzene, diethylbenzene and the like. Wherein the reaction temperature is preferably 330 ℃, the pressure is preferably 0.8-1.0 MPa, and the molecular molar ratio of the benzene to the ethylene in the dry gas is preferably (6-9) to 1. In the present invention, the alkylation reactor may be provided in two, 1 for operation, the other 1 for standby, or two reactors may be used in parallel. After the alkylation reaction, the obtained materials comprise a main product ethylbenzene, byproducts (propylbenzene, diethylbenzene and the like) and residual benzene. The temperature of the obtained material is 360 ℃, and the pressure is 1.0MPa.
(2) Discharging the material obtained from the alkylation reactor from the bottom, preferably cooling to 150 ℃ through heat exchange, and then feeding the material into a rough separation tower, wherein the working conditions of the rough separation tower are as follows: the temperature at the top of the tower is 98-130 ℃, and the pressure at the top of the tower is 0.45-0.6 MPa. Under the operating conditions, the non-condensable gas is separated from the materials, the formed tower bottom materials are sent into a benzene tower of a subsequent separation unit for re-separation, the non-condensable gas at the tower top of the component tower is cooled to 10 ℃, then enters an absorption tower (enters from the lower part or the bottom part) and is in countercurrent contact with an absorbent diethylbenzene from top to bottom, and heavy components in the absorbent diethylbenzene are absorbed; and the absorbed tail gas is discharged from the top of the absorption tower, one part of the tail gas is used as a self-use fuel of the device, and the other part of the tail gas enters a pipe network. The material at the bottom of the absorption tower is mixed with the circulating benzene and enters the anti-alkylation reactor.
(3) The material entering the anti-alkylation reactor is subjected to anti-alkylation reaction, namely the byproducts of diethylbenzene, propylbenzene and butylbenzene are subjected to anti-alkylation reaction with benzene under certain operating conditions and catalysis, and then are converted into ethylbenzene. The temperature of the materials obtained by the reaction is 260 ℃, and the pressure in the reactor is 3.6MPa. And (4) sending the obtained material to a subsequent separation unit for separating a main product from a byproduct.
In the present invention, the separation unit 2 includes:
the feed inlet of the ethylbenzene tower unit 2b is communicated with the discharge outlet of the benzene tower unit;
a propylbenzene tower unit 2c with a feeding hole communicated with the discharge hole of the ethylbenzene tower unit;
a diethylbenzene column unit 2d with a feed inlet communicated with the propylbenzene column unit.
The operation of the separation unit 2 is as follows:
(1) The benzene tower unit 2a receives the tower bottom materials from the anti-alkylation reactor 1d and the crude separation tower 1b, the materials are separated in a benzene tower, oil gas benzene is evaporated from the top of the tower, the benzene tower bottom materials are divided into two parts, one part is used as a heat source of a reboiler of an ethylbenzene tower, a propylbenzene tower and a diethylbenzene tower after being pressurized, and finally the part is heated by a reboiling furnace at the bottom of the benzene tower and returns to the bottom of the benzene tower, and the other part enters the ethylbenzene tower unit for subsequent separation. The top temperature of the benzene tower in the benzene tower unit is 190-205 ℃, the top pressure is 1.1-1.58 KPa, and the bottom temperature is 260-280 ℃.
(2) The ethylbenzene column unit 2b receives the material at the bottom of the benzene column unit 2a, and then the material is rectified and separated in the ethylbenzene column, the ethylbenzene has low relative volatility and is gradually enriched towards the top of the column, and other components such as propylbenzene have high relative volatility and are gradually enriched towards the bottom of the column, so that the main product ethylbenzene is separated from other components.
In some embodiments of the present invention, the structure of the ethylbenzene column unit 2b is shown in fig. 4, and fig. 4 is a schematic structural diagram of the ethylbenzene column unit in the present invention, which specifically includes:
a steam generator 2b-2 with an air inlet communicated with an air outlet at the top of the ethylbenzene tower;
a reflux tank 2b-3 with a feeding hole communicated with a discharge hole of the steam generator;
a reflux pump 2b-4 with a liquid inlet communicated with the liquid outlet of the reflux tank; a liquid outlet of the reflux pump is respectively communicated with a liquid return port of the ethylbenzene tower and a liquid inlet of an ethylbenzene product condenser 2 b-5;
a tower bottom material delivery pump 2b-6 communicated with the tower bottom material outlet of the ethylbenzene tower;
and a tower bottom reboiler 2b-7 communicated with the tower kettle of the ethylbenzene tower.
Specifically, gas phase enriched at the top of the ethylbenzene tower 2b-1 is discharged and then enters a steam generator 2b-2 for heat exchange to generate 0.35MPa steam, the material after heat exchange and temperature reduction enters a reflux tank 2b-3, non-condensable gas is discharged from the top of the reflux tank 2b-3, and tank bottom liquid is extracted through a reflux pump 2 b-4. The produced liquid is divided into two parts: one part of the mixed gas flows back to the upper part or the top of the ethylbenzene tower 2b-1, and the other part of the mixed gas is sent out after being condensed by an ethylbenzene product condenser 2b-5 to obtain an ethylbenzene product. The material at the bottom of the ethylbenzene column 2b-1 is extracted by a material conveying pump 2b-6 at the bottom of the ethylbenzene column and sent to a subsequent propylbenzene column unit.
In the prior art, in order to ensure the quality of an ethylbenzene product, the pressure control of an ethylbenzene tower in an ethylbenzene tower unit is higher, and a large reflux ratio (more than 3.9) is adopted. In the invention, the reflux ratio of the ethylbenzene tower is reduced, and the temperature of the tower kettle is controlled, so that while the ethylbenzene product at the tower top is ensured, the ethylbenzene content of the material at the tower bottom of the ethylbenzene tower can be effectively reduced, the ethylbenzene loss is reduced, and meanwhile, the load of an ethylbenzene product condenser and the load of an ethylbenzene reboiler at the tower bottom of the ethylbenzene tower in the ethylbenzene tower unit are reduced, thereby effectively reducing the energy consumption of the device. In the present invention, the overhead reflux ratio of the ethylbenzene column is controlled to be 1.80 to 3.30, preferably 2.4 to 3.30, and in some embodiments of the present invention, the reflux ratio is 1.90, 1.91, 2.4, 3.0, 3.20 or 3.26. In the present invention, the temperature of the bottom of the ethylbenzene column is controlled to be 220-221 ℃, and in some embodiments of the present invention, the temperature is 220.9 ℃ or 221.0 ℃.
In the invention, the tower top pressure of the ethylbenzene tower is preferably 80-120 KPa, and the tower top temperature is preferably 158-168 ℃. In some embodiments of the invention, the overhead pressure is 95KPa, 100KPa, or 104KPa. In some embodiments of the invention, the overhead temperature is 162.75 ℃, 164 ℃, 164.80 ℃, 164.83 ℃.
In the invention, the pressure of the bottom of the ethylbenzene tower is preferably 145-170 KPa. In some embodiments of the invention, the column bottom pressure is 148KPa.
In the invention, the feeding flow of the ethylbenzene tower is preferably 5.8-9.5 t/h, the feeding temperature is preferably 243-252 ℃, and the feeding pressure is preferably 155-160 KPa. In some embodiments of the invention, the feed flow rate is 5.8t/h, 6.0t/h, 6.5t/h, 7.0t/h, or 9.5t/h; in some embodiments of the invention, the feed temperature is 243 ℃ or 252 ℃; in some embodiments of the invention, the feed pressure is 155KPa or 160KPa.
In the present invention, the reflux temperature of the ethylbenzene column unit is preferably 135 to 140 ℃. In some embodiments of the invention, the reflux temperature is 137 ℃. The reflux temperature refers to the return temperature of the liquid pumped by the reflux pump 2b-4 when the liquid returns to the ethylbenzene column 2 b-1.
In the present invention, the ethylbenzene delivery temperature of the ethylbenzene column unit is preferably 10 to 40 ℃. In some embodiments of the invention, the outfeed temperature is 40 ℃. The delivery temperature is the temperature at which the ethylbenzene product is cooled by the ethylbenzene product condenser 2 b-5.
(3) Materials at the bottom of the ethylbenzene column 2b-1 are extracted by a material conveying pump 2b-6 at the bottom of the ethylbenzene column and are sent to a propylbenzene column unit 2c, propylbenzene byproducts are evaporated at the top of the ethylbenzene column and are divided into two paths: one part of the reflux liquid is returned, and the other part of the reflux liquid is taken as a by-product and sent out of the device after being cooled. The tower bottom material enters a subsequent diethylbenzene tower unit for continuous separation.
In the invention, the temperature of the top of the propyl benzene tower in the propyl benzene tower unit 2c is 170-180 ℃, the pressure of the top of the propyl benzene tower is 60-100 KPa, and the temperature of the bottom of the propyl benzene tower is 205-215 ℃.
(4) The diethylbenzene column unit 2d receives the material from the bottom of the propylbenzene column unit 2c, and the diethylbenzene is distilled from the top of the propylbenzene column and is divided into two paths: one part of the reflux liquid is used as an absorbent to exchange heat with the material at the bottom of the absorption tower, and the other part of the reflux liquid enters the absorption tower. And (4) sending high-boiling residues at the bottom of the diethylbenzene tower out of the device.
In the invention, the temperature of the top of the ethylbenzene column in the ethylbenzene column unit 2d is 155-160 ℃, the pressure of the top of the ethylbenzene column is-35 KPa to-55 KPa, and the temperature of the bottom of the ethylbenzene column is 195-210 ℃.
In the process for synthesizing the ethylbenzene, the overhead reflux ratio of the ethylbenzene tower is reduced, specifically controlled to be 1.80-3.30, the temperature of a tower kettle of the ethylbenzene tower is increased, specifically controlled to be 220-221 ℃, and therefore the ethylbenzene content of materials at the bottom of the ethylbenzene tower can be effectively reduced, the ethylbenzene loss is reduced, meanwhile, the ethylbenzene product condenser load and the ethylbenzene reboiler load at the bottom of the ethylbenzene tower of an ethylbenzene tower unit are reduced, and therefore the energy consumption of the device is effectively reduced.
For a further understanding of the present invention, reference will now be made to the following preferred embodiments of the invention in conjunction with the examples, but it is to be understood that the description is intended to further illustrate the features and advantages of the invention and is not intended to limit the scope of the claims which follow.
Examples 1 to 4 and comparative example 1
The synthesis and separation of ethylbenzene was carried out according to the synthesis plant shown in fig. 3, as described hereinbefore, wherein the operating parameters of the units other than the ethylbenzene column unit 2b are as follows:
the reaction unit operating parameters were as follows:
an alkylation reactor: the reaction temperature is 330 ℃, and the pressure is 0.9MPa; the molecular molar ratio of benzene to ethylene in the dry gas is 7: 1. The temperature of the materials obtained by the reaction is 360 ℃, and the materials are sent to a rough separation tower after being cooled to 150 ℃.
Roughly dividing the tower: the temperature at the top of the column is 122 ℃, the temperature at the bottom of the column is 135 ℃ and the pressure at the top of the column is 0.56Mpa.
An absorption tower: the temperature at the top of the column was 23.7 ℃, the temperature at the bottom of the column was 23.4 ℃ and the pressure at the top of the column was 0.49MPa.
An anti-alkylation reactor: the reaction temperature is 240 ℃, and the pressure is 3.5MPa; the temperature of the materials obtained by the reaction is 240 ℃, and the pressure in the reactor is 3.5MPa.
The separation unit operating parameters were as follows:
a benzene tower: the column top temperature was 203 ℃, the column bottom temperature was 276 ℃ and the column top pressure was 1.42MPa.
An ethylbenzene column: see below.
A propylbenzene tower: the tower top temperature is 172 ℃, the tower bottom temperature is 210 ℃ and the tower top pressure is 80KPa.
A diethylbenzene column: the temperature at the top of the tower is 156 ℃, the temperature at the bottom of the tower is 207 ℃, and the pressure at the top of the tower is-45 KPa.
The structure of the ethylbenzene column unit 2b is shown in FIG. 4, wherein the operating parameters, as well as the effluent quality and equipment load, of the ethylbenzene column unit 2b of examples 1-4 and comparative example 1 are shown in Table 1:
table 1 operating conditions and effects of examples 1 to 4 and comparative example 1
As can be seen from Table 1, in the process for synthesizing ethylbenzene, the overhead reflux ratio of the ethylbenzene tower is reduced and is specifically controlled to be 1.80-3.30, the tower kettle temperature of the ethylbenzene tower is improved and is specifically controlled to be 220-221 ℃, and as a result, on the basis of ensuring the quality of an ethylbenzene product (the ethylbenzene content of a tower top material is more than 99.8%), the ethylbenzene content of a tower bottom material of the ethylbenzene tower can be effectively reduced, the ethylbenzene loss is reduced, and meanwhile, the ethylbenzene product condenser load and the ethylbenzene tower bottom reboiler load of an ethylbenzene tower unit are reduced, so that the energy consumption of a device is effectively reduced.
Examples 5 to 7
The procedure was as in example 1 except that the operating parameters of ethylbenzene column unit 2b were as shown in Table 2, and the corresponding effluent quality and equipment load were also as shown in Table 2.
TABLE 2 operating conditions and effects of examples 5 to 7
As can be seen from Table 2, when the reflux ratio is determined, the influence on the condenser load and the reboiler load is small and the energy consumption is not changed greatly by adjusting the feeding conditions.
Examples 8 to 10
The procedure of example 1 was followed except that the operating parameters of ethylbenzene column unit 2b are as shown in table 3, and the corresponding product quality and equipment load are also shown in table 3.
TABLE 3 operating conditions and effects of examples 8 to 10
As can be seen from Table 3, when the reflux ratio is determined, the effect on the condenser load and the reboiler load is small and the energy consumption is not changed much by adjusting the pressure condition of the top of the ethylbenzene column.
As can be seen from tables 1 to 3, in the process for synthesizing ethylbenzene, the overhead reflux ratio of the ethylbenzene tower is reduced, specifically controlled to be 1.80-3.30, the tower kettle temperature of the ethylbenzene tower is increased, specifically controlled to be 220-221 ℃, and as a result, on the basis of ensuring the quality of an ethylbenzene product (the ethylbenzene content of a tower top material is more than 99.8%), the ethylbenzene content of a tower bottom material of the ethylbenzene tower can be effectively reduced, the ethylbenzene loss is reduced, and meanwhile, the ethylbenzene product condenser load and the ethylbenzene tower bottom reboiler load of an ethylbenzene tower unit are reduced, so that the energy consumption of a device is effectively reduced. After the reflux ratio is determined to be in the range, other parameters are adjusted to have little influence on the energy consumption of the device, and the product quality can be ensured and the ethylbenzene loss at the tower bottom and the energy consumption of the device can be reduced only by controlling the temperature of the tower bottom and the reflux ratio.
The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (5)
1. A method for reducing ethylbenzene loss and energy consumption of an ethylbenzene tower in an ethylbenzene synthesis process is characterized by comprising the following steps:
after the dry gas and the benzene react in a reaction unit of the ethylbenzene synthesis device, separating a main product ethylbenzene and a byproduct from the obtained reactant through a separation unit, wherein the ethylbenzene product and a tower bottom material are obtained after the separation treatment of an ethylbenzene tower unit in the separation unit;
wherein the ethylbenzene column unit comprises:
an ethylbenzene column;
the gas inlet of the steam generator is communicated with the gas outlet at the top of the ethylbenzene tower;
the feed inlet is communicated with the discharge port of the steam generator;
the liquid inlet of the reflux pump is communicated with the liquid outlet of the reflux tank; a liquid outlet of the reflux pump is respectively communicated with a liquid return port of the ethylbenzene tower and a liquid inlet of the ethylbenzene product condenser;
a tower bottom delivery pump is communicated with a tower bottom discharge hole of the ethylbenzene tower;
a tower bottom reboiler communicated with the tower kettle of the ethylbenzene tower;
in the ethylbenzene tower unit, the temperature of a tower kettle of an ethylbenzene tower is controlled to be 220 to 221 ℃, the reflux ratio of a tower top is controlled to be 1.80 to 2.4, the pressure of the tower top is 80 to 120KPa, the temperature of the tower top is 158 to 168 ℃, the pressure of the tower kettle is 145 to 170KPa, and the reflux temperature is 135 to 140 ℃.
2. The process according to claim 1, characterized in that the ethylbenzene export temperature of the ethylbenzene column unit is 10 to 40 ℃.
3. The method according to claim 1, wherein the feeding flow rate of the ethylbenzene tower is 5.8 to 9.5t/h, the feeding temperature is 243 to 252 ℃, and the feeding pressure is 155 to 160KPa.
4. The method of claim 1, wherein the separation unit comprises:
a benzene column unit;
the feed inlet of the ethylbenzene tower unit is communicated with the discharge outlet of the benzene tower unit;
a propylbenzene tower unit with a feeding hole communicated with the discharge hole of the ethylbenzene tower unit;
and the feeding hole of the diethylbenzene tower unit is communicated with the propylbenzene tower unit.
5. The method of claim 1, wherein the reaction unit comprises:
an alkylation reactor;
the feeding port of the coarse fractionating tower is communicated with the discharge port of the alkylation reactor;
the gas inlet is communicated with the gas outlet at the top of the rough separation tower;
the feed inlet is communicated with the discharge hole of the absorption tower;
the anti-alkylation reactor is communicated with the benzene tower unit in the separation unit, and the tower bottom discharge port of the coarse separation tower is communicated with the benzene tower unit in the separation unit.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1299798A (en) * | 1999-12-10 | 2001-06-20 | 北京服装学院 | Benzene and oil refinery dry gas catalyzed alkylation distillation process and equipment of preparing ethylbenzene |
| CN107935805A (en) * | 2017-12-15 | 2018-04-20 | 大连理工大学 | The preparing ethylbenzene from dry gas device product-enlarging method risen based on feed ethylene content |
| JP2019151644A (en) * | 2019-04-25 | 2019-09-12 | エスシージー ケミカルズ カンパニー，リミテッド | Process for enhanced separation of ethylbenzene |
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| KR102397644B1 (en) * | 2017-06-16 | 2022-05-13 | 에스케이이노베이션 주식회사 | A method for recovering an ethylbenzene from the alkylation product of fluidized catalytic cracking OFF-GAS and Benzene |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1299798A (en) * | 1999-12-10 | 2001-06-20 | 北京服装学院 | Benzene and oil refinery dry gas catalyzed alkylation distillation process and equipment of preparing ethylbenzene |
| CN107935805A (en) * | 2017-12-15 | 2018-04-20 | 大连理工大学 | The preparing ethylbenzene from dry gas device product-enlarging method risen based on feed ethylene content |
| JP2019151644A (en) * | 2019-04-25 | 2019-09-12 | エスシージー ケミカルズ カンパニー，リミテッド | Process for enhanced separation of ethylbenzene |
Non-Patent Citations (1)
| Title |
|---|
| 乙苯装置循环苯塔侧线采出工艺的优化与改造;焦书建;《石化技术与应用》;20050725(第04期);第288-290页 * |
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