阅读说明：本技术 一种二乙苯脱氢制二乙烯基苯的反应系统及反应方法 (Reaction system and reaction method for preparing divinylbenzene through dehydrogenation of diethylbenzene ) 是由 张彬 刘文杰 于 2020-05-08 设计创作，主要内容包括：本发明公开了一种二乙苯脱氢制二乙烯基苯的反应系统及反应方法。系统包括：第一脱氢反应器、第二脱氢反应器、加热炉、第二脱氢反应器进料换热器和第二脱氢反应器出料换热器；二乙苯进料管线连接第二脱氢反应器出料换热器后连接第一脱氢反应器底部；水蒸气进料管线连接加热炉,加热炉出口管线有两支,一支连接第一脱氢反应器底部,另一支连接第二脱氢反应器进料换热器后返回加热炉；第一脱氢反应器侧面出口管线连接第二脱氢反应器进料换热器后与第二脱氢反应器底部连接；第二脱氢反应器侧面出口管线连接第二脱氢反应器出料换热器后送出界外。本发明操作简单、工艺布置合理、二乙烯基目标组分高,可具体工业应用的特点。(The invention discloses a reaction system and a reaction method for preparing divinylbenzene by dehydrogenating diethylbenzene. The system comprises: the device comprises a first dehydrogenation reactor, a second dehydrogenation reactor, a heating furnace, a second dehydrogenation reactor feeding heat exchanger and a second dehydrogenation reactor discharging heat exchanger; the diethylbenzene feeding pipeline is connected with the discharge heat exchanger of the second dehydrogenation reactor and then connected with the bottom of the first dehydrogenation reactor; the steam feeding pipeline is connected with the heating furnace, two heating furnace outlet pipelines are provided, one pipeline is connected with the bottom of the first dehydrogenation reactor, and the other pipeline is connected with the feeding heat exchanger of the second dehydrogenation reactor and then returns to the heating furnace; the outlet pipeline on the side surface of the first dehydrogenation reactor is connected with the feeding heat exchanger of the second dehydrogenation reactor and then is connected with the bottom of the second dehydrogenation reactor; and the outlet pipeline on the side surface of the second dehydrogenation reactor is connected with a discharge heat exchanger of the second dehydrogenation reactor and then is discharged outside. The method has the characteristics of simple operation, reasonable process arrangement, high divinyl target component and specific industrial application.)

1. A reaction system for preparing divinylbenzene by dehydrogenating diethylbenzene is characterized by comprising:

the device comprises a first dehydrogenation reactor, a second dehydrogenation reactor, a heating furnace, a second dehydrogenation reactor feeding heat exchanger and a second dehydrogenation reactor discharging heat exchanger;

the diethylbenzene feeding pipeline is connected with the discharge heat exchanger of the second dehydrogenation reactor and then connected with the bottom of the first dehydrogenation reactor; the steam feeding pipeline is connected with the heating furnace, two heating furnace outlet pipelines are provided, one pipeline is connected with the bottom of the first dehydrogenation reactor, and the other pipeline is connected with the feeding heat exchanger of the second dehydrogenation reactor and then returns to the heating furnace;

the outlet pipeline on the side surface of the first dehydrogenation reactor is connected with the feeding heat exchanger of the second dehydrogenation reactor and then is connected with the bottom of the second dehydrogenation reactor; and the outlet pipeline on the side surface of the second dehydrogenation reactor is connected with a discharge heat exchanger of the second dehydrogenation reactor and then is discharged outside.

2. The reaction system for preparing divinylbenzene by dehydrogenation of diethylbenzene as claimed in claim 1, wherein:

a raw material mixer is arranged at the bottom of the first dehydrogenation reactor; the raw material mixer is connected with the first dehydrogenation reactor;

the diethylbenzene feeding pipeline is connected with the discharge heat exchanger of the second dehydrogenation reactor and then connected with the raw material mixer; the steam feeding pipeline is connected with the heating furnace, two heating furnace outlet pipelines are provided, one pipeline is connected with the raw material mixer, and the other pipeline is connected with the feeding heat exchanger of the second dehydrogenation reactor and then returns to the heating furnace.

3. The reaction system for preparing divinylbenzene by dehydrogenation of diethylbenzene as claimed in claim 1, wherein:

the outlet pipeline of the first dehydrogenation reactor is arranged on the side wall of the reactor, and the distance from the outlet pipeline to the bottom of the dehydrogenation reactor accounts for 10-30% of the total height of the dehydrogenation reactor.

4. The reaction system for preparing divinylbenzene by dehydrogenation of diethylbenzene as claimed in claim 1, wherein:

the outlet pipeline of the second dehydrogenation reactor is arranged on the side wall of the reactor, and the distance from the outlet pipeline to the bottom of the dehydrogenation reactor accounts for 10-30% of the total height of the dehydrogenation reactor.

5. A reaction method for preparing divinylbenzene by dehydrogenation of diethylbenzene by using the system as claimed in any one of claims 1 to 4, wherein said method comprises:

(a) after exchanging heat with the discharge of the second dehydrogenation reactor, the raw material diethylbenzene is mixed with high-temperature steam and enters the first dehydrogenation reactor to carry out dehydrogenation reaction under the conditions of a dehydrogenation catalyst and negative pressure;

(b) discharging the reaction gas of the first dehydrogenation reactor from the side surface of the reactor, exchanging heat with high-temperature steam, then entering a second dehydrogenation reactor, and carrying out dehydrogenation reaction under the conditions of a dehydrogenation catalyst and negative pressure;

(c) and the reaction gas of the second dehydrogenation reactor is discharged from the side surface of the reactor, exchanges heat with the diethylbenzene raw material and then is sent to the rectification unit.

6. The reaction process for preparing divinylbenzene by dehydrogenation of diethylbenzene as claimed in claim 5, wherein:

and (a) after heat exchange is carried out between raw material diethylbenzene and the discharge of the second dehydrogenation reactor, the raw material diethylbenzene enters a raw material mixer, is fully mixed with high-temperature steam in the raw material mixer, then enters the first dehydrogenation reactor, and is subjected to dehydrogenation reaction under the conditions of a dehydrogenation catalyst and negative pressure.

7. The reaction process for preparing divinylbenzene by dehydrogenation of diethylbenzene as claimed in claim 6, wherein:

the mass ratio of the water vapor to the raw material diethylbenzene is 1.2-2;

the operating pressure of the first dehydrogenation reactor is 20-90 kpa;

the temperature of the mixture of the raw material diethylbenzene and the water vapor is 580-640 ℃.

8. The reaction process for preparing divinylbenzene by dehydrogenation of diethylbenzene as claimed in claim 6, wherein:

step (b), the reaction gas of the first dehydrogenation reactor exchanges heat with high-temperature steam to 590-650 ℃ and enters a second dehydrogenation reactor;

the operating pressure of the second dehydrogenation reactor is 20-90 kpa;

the mass content of the divinylbenzene in the reaction gas of the second dehydrogenation reactor is 21-28%.

9. The reaction process for preparing divinylbenzene by dehydrogenation of diethylbenzene as claimed in claim 6, wherein:

the reaction gas of the second dehydrogenation reactor exchanges heat with the raw material diethylbenzene, and the raw material diethylbenzene is heated to 490-520 ℃ and mixed with water vapor and then enters the first dehydrogenation reactor.

10. The reaction process for preparing divinylbenzene by dehydrogenation of diethylbenzene as claimed in claim 6, wherein:

the total pressure drop of the operating pressure of the first dehydrogenation reactor and the operating pressure of the second dehydrogenation reactor is controlled within 11 Kpa.

Technical Field

The invention relates to the technical field of divinylbenzene production, and further relates to a reaction system and a reaction method for preparing divinylbenzene by dehydrogenating diethylbenzene.

Background

Divinylbenzene is a very useful crosslinking agent, mainly used in the manufacture of plastics and ion exchange resins. Divinyl benzene is rich in reactivity, can generate insoluble polymers with three-dimensional structures, is used as a crosslinking agent, and can be copolymerized with polymerizable monomers such as styrene, butadiene, acrylonitrile, methacrylic acid and the like to prepare ion exchange resins and the like. In general, the higher the crosslinking speed of divinylbenzene, the higher the content of para-isomer, the better the properties of the resin. The consumption proportion of divinylbenzene in various application fields is 66.8 percent of ion exchange resin, 13.9 percent of special plastic, 7.3 percent of rubber, 3.2 percent of coating, 2.3 percent of adhesive, 1.3 percent of electron and 5.2 percent of others in sequence on the global scale. In the coming years, the annual growth rate of each application field of the divinylbenzene is 4.1 percent of ion exchange resin, 3.6 percent of special plastic, 3.5 percent of rubber, 3.2 percent of coating, 3.2 percent of adhesive, 3.9 percent of electron and 3.3 percent of others in sequence.

When ethylbenzene is prepared by alkylating ethylene and benzene, mixed diethylbenzene is obtained as a by-product, and three isomers of the diethylbenzene have similar boiling points and are difficult to separate. Therefore, o-, m-, and p-divinylbenzene can be usually prepared by mixing diethylbenzene raw materials and dehydrogenating. Divinylbenzene is currently available in higher prices, but currently there are few patents and syntheses related to divinylbenzene, and particularly few reaction syntheses related to divinylbenzene. Chinese patent CN1884240A reports a method for preparing divinylbenzene by catalytic dehydrogenation, which mainly solves the technical problem of low product yield in the production of divinylbenzene by catalytic dehydrogenation. The invention adopts the technical scheme that Mo and W are introduced in a proper mixing proportion in a Fe-K-Ce-Mo catalyst system, so that the catalyst has higher catalytic activity and selectivity, the technical problem is solved, and the catalyst can be used for industrial production for preparing divinylbenzene by catalytic dehydrogenation.

Chinese patent CN200510028776.5 relates to a method for preparing divinylbenzene by dehydrogenation of diethylbenzene, and mainly solves the technical problem of low product yield in the dehydrogenation of diethylbenzene. The invention adjusts the proportion of the elements in an FE-K-CE-MO catalyst system, and simultaneously adds a plurality of rare earth element compounds, so that the catalyst keeps higher selectivity and carbon deposit resistance, solves the technical problem, and can be used in the industrial production of preparing divinylbenzene by diethylbenzene dehydrogenation. US patent US,982,030famine, invented a process for the preparation of p-divinylbenzene: firstly, dehydrogenating diethylbenzene, and then crystallizing and separating divinylbenzene. The p-diethylbenzene in the experiment is prepared by alkylating ethylbenzene and ethylene in the presence of a molecular sieve catalyst, such as modified ZSM-5, and a specific process for dehydrogenation is not given in the patent.

Although several patents describe the preparation of divinylbenzene, most are based on the preparation of divinylbenzene catalysts, and do not relate to the specific reaction process of how divinylbenzene is converted to divinylbenzene.

The existing dehydrogenation reactor is provided with two reactors, and a discharge outlet of the reactor is arranged at the top of the side surface, so that the equipment is very inconvenient to overhaul, the catalyst is inconvenient to load, the pressure drop of a dehydrogenation reaction system is large, the fluid in the reactor is uneven in distribution, and the energy consumption of a subsequent compressor system is large.

Disclosure of Invention

Aims to solve the problems of low concentration of divinylbenzene, difficult filling of a reactor catalyst, complex reaction process and large pressure drop of reaction in the prior art in the dehydrogenation reaction of the diethylbenzene. The invention provides a reaction system and a reaction method for preparing divinylbenzene by dehydrogenating diethylbenzene. The method has the characteristics of simple operation, reasonable process arrangement, high divinyl target component and specific industrial application.

The invention aims to provide a reaction system for preparing divinylbenzene by dehydrogenating diethylbenzene.

The system comprises:

the device comprises a first dehydrogenation reactor, a second dehydrogenation reactor, a heating furnace, a second dehydrogenation reactor feeding heat exchanger and a second dehydrogenation reactor discharging heat exchanger;

the diethylbenzene feeding pipeline is connected with the discharge heat exchanger of the second dehydrogenation reactor and then connected with the bottom of the first dehydrogenation reactor; the steam feeding pipeline is connected with the heating furnace, two heating furnace outlet pipelines are provided, one pipeline is connected with the bottom of the first dehydrogenation reactor, and the other pipeline is connected with the feeding heat exchanger of the second dehydrogenation reactor and then returns to the heating furnace;

the outlet pipeline on the side surface of the first dehydrogenation reactor is connected with the feeding heat exchanger of the second dehydrogenation reactor and then is connected with the bottom of the second dehydrogenation reactor; and the outlet pipeline on the side surface of the second dehydrogenation reactor is connected with a discharge heat exchanger of the second dehydrogenation reactor and then is discharged outside.

Among them, preferred are:

a raw material mixer is arranged at the bottom of the first dehydrogenation reactor; the raw material mixer is connected with the first dehydrogenation reactor;

the diethylbenzene feeding pipeline is connected with the discharge heat exchanger of the second dehydrogenation reactor and then connected with the raw material mixer; the steam feeding pipeline is connected with the heating furnace, two heating furnace outlet pipelines are provided, one pipeline is connected with the raw material mixer, and the other pipeline is connected with the feeding heat exchanger of the second dehydrogenation reactor and then returns to the heating furnace.

The outlet pipeline of the first dehydrogenation reactor is arranged on the side wall of the reactor, and the distance from the outlet pipeline to the bottom of the dehydrogenation reactor accounts for 10-30% of the total height of the dehydrogenation reactor;

the outlet pipeline of the second dehydrogenation reactor is arranged on the side wall of the reactor, and the distance from the outlet pipeline to the bottom of the dehydrogenation reactor accounts for 10-30% of the total height of the dehydrogenation reactor.

The second purpose of the invention is to provide a reaction method for preparing divinylbenzene by dehydrogenating diethylbenzene.

The method comprises the following steps:

(a) after exchanging heat with the discharge of the second dehydrogenation reactor, the raw material diethylbenzene is mixed with high-temperature steam and enters the first dehydrogenation reactor to carry out dehydrogenation reaction under the conditions of a dehydrogenation catalyst and negative pressure;

(b) discharging the reaction gas of the first dehydrogenation reactor from the side surface of the reactor, exchanging heat with high-temperature steam, then entering a second dehydrogenation reactor, and carrying out dehydrogenation reaction under the conditions of a dehydrogenation catalyst and negative pressure;

(c) and the reaction gas of the second dehydrogenation reactor is discharged from the side surface of the reactor, exchanges heat with the diethylbenzene raw material and then is sent to the rectification unit.

Among them, preferred are:

and (a) after heat exchange is carried out between raw material diethylbenzene and the discharge of the second dehydrogenation reactor, the raw material diethylbenzene enters a raw material mixer, is fully mixed with high-temperature steam in the raw material mixer, then enters the first dehydrogenation reactor, and is subjected to dehydrogenation reaction under the conditions of a dehydrogenation catalyst and negative pressure.

The mass ratio of the water vapor to the raw material diethylbenzene is 1.2-2;

the operating pressure of the first dehydrogenation reactor is 20-90 kpa;

the temperature of the mixture of the raw material diethylbenzene and the water vapor is 580-640 ℃.

Step (b), the reaction gas of the first dehydrogenation reactor exchanges heat with high-temperature steam to 590-650 ℃ and enters a second dehydrogenation reactor;

the operating pressure of the second dehydrogenation reactor is 20-90 kpa;

the mass content of the divinylbenzene in the reaction gas of the second dehydrogenation reactor is 21-28%.

The reaction gas of the second dehydrogenation reactor exchanges heat with the raw material diethylbenzene, and the raw material diethylbenzene is heated to 490-520 ℃ and mixed with water vapor and then enters the first dehydrogenation reactor.

The total pressure drop of the operating pressure of the first dehydrogenation reactor and the operating pressure of the second dehydrogenation reactor is controlled within 11 Kpa.

The invention can adopt the following technical scheme:

a reaction method for preparing divinylbenzene by dehydrogenating diethylbenzene comprises the following steps: a) after exchanging heat between the discharging heat exchanger VI and the discharging material of the second dehydrogenation reactor, the raw material diethylbenzene enters an inlet mixer II of the first dehydrogenation reactor III, is fully mixed with high-temperature steam from a heating furnace I B chamber, and enters the first dehydrogenation reactor III to perform dehydrogenation reaction under the conditions of a dehydrogenation catalyst and negative pressure. b) And (b) after the step (a) is finished, discharging the reaction gas of the first dehydrogenation reactor from the side surface of the reactor III, exchanging heat with high-temperature steam from the chamber IA of the heating furnace, then entering the second dehydrogenation reactor IV, and carrying out dehydrogenation reaction under the conditions of a dehydrogenation catalyst and negative pressure. c) And (c) after the steps (a) and (b) are finished, discharging the reaction gas of the second dehydrogenation reactor IV from the bottom of the side surface of the reactor, exchanging heat with the diethylbenzene raw material through a discharge heat exchanger VI, and sending the reaction gas to a rectification unit.

In the technical scheme, the mass ratio of raw material diethylbenzene to water (1) in the step a) is 1.2-2, the operating pressure of the first dehydrogenation reactor III is 20-90kpa, the temperature of the mixed raw material and steam in front of the first dehydrogenation reactor III is 580-640 ℃, the reaction gas of the first dehydrogenation reactor is discharged from the side surface of the first dehydrogenation reactor III, and the distance from the outlet position of the reaction gas to the bottom of the dehydrogenation reactor accounts for 10-30% of the total height of the dehydrogenation reactor;

in the technical scheme, the reaction gas of the first dehydrogenation reactor and high-temperature steam from a heating furnace enter a second dehydrogenation reactor IV at the temperature of 590-650 ℃ after heat exchange in a heat exchanger V, the operating pressure of the second dehydrogenation reactor IV is 20-90kpa, the reaction gas of the second dehydrogenation reactor is discharged from the bottom of the side surface of the second dehydrogenation reactor IV, and the distance between the outlet position of the reaction gas and the bottom of the dehydrogenation reactor accounts for 10-30% of the total height of the dehydrogenation reactor; the mass content of the divinyl benzene in the dehydrogenation reaction gas of the second dehydrogenation reactor IV is 21-28%, the dehydrogenation reaction gas of the second dehydrogenation reactor IV exchanges heat with the raw material in a heat exchanger VI, the raw material is heated to 490-520 ℃, and the raw material and the water vapor are mixed in a mixer II and then enter a first dehydrogenation reactor III.

In the technical scheme, the total pressure drop is controlled within 11Kpa from the operating pressure of the first dehydrogenation reactor III to the operating pressure of the second dehydrogenation reactor IV.

In the invention, the high-temperature steam is heated by the heating furnace I, and the mass ratio of para-diethylbenzene to meta-diethylbenzene in the diethylbenzene raw material can be changed, so that the proportion of para-diethylbenzene to para-diethylbenzene in the product can be adjusted, and the method can adapt to different production requirements. The invention reasonably integrates energy, effectively improves the energy utilization efficiency, adopts a mode of downward feeding and downward discharging for feeding and discharging of the reactor, and does not influence the agent filling due to the inconvenience of the position of a discharging pipeline when filling the catalyst, so that the device inspection and the catalyst filling are very convenient; the operation cost is greatly saved. The invention can produce high-quality divinylbenzene, the product has high purity, less impurities, reasonable comparison, and the obtained product divinylbenzene can be used as a high-quality raw material for producing high-performance ion exchange resin, thereby obtaining better technical effect.

Drawings

FIG. 1 is a schematic diagram of a reaction system for preparing divinylbenzene by dehydrogenating diethylbenzene according to the present invention;

in fig. 1: i is a heating furnace, A and B are respectively heating zones of the heating furnace, II is a mixer of raw material diethylbenzene and steam of a first dehydrogenation reactor, III is the first dehydrogenation reactor, IV is a second dehydrogenation reactor, V is a feeding heat exchanger of the second dehydrogenation reactor, and VI is a discharging heat exchanger of the second dehydrogenation reactor. 1 is water, 2 is raw materials diethylbenzene, 3 is the diethylbenzene feeding after ejection of compact heat exchanger VI heating, 4 is the high-temperature steam after heating furnace IA heating, 5 is the high-temperature steam after the heat transfer, 6 is the high-temperature steam after heating furnace IB heating, 7 is the reactor ejection of compact of first dehydrogenation ware III, 8 is the dehydrogenation raw materials after second dehydrogenation ware feeding heat exchanger heating, 9 is the reactor ejection of compact of second dehydrogenation ware IV, 10 is the reaction gas after the heat transfer cooling of second dehydrogenation ware ejection of compact heat exchanger VI, 11 is first dehydrogenation ware catalyst loading mouth, 12 is second dehydrogenation ware catalyst loading mouth.

In the figure 1, after heat exchange is carried out between a discharging heat exchanger VI and the discharging material of a second dehydrogenation reactor IV, raw material diethylbenzene enters an inlet mixer II of a first dehydrogenation reactor III, is fully mixed with high-temperature steam from a heating furnace I B, enters the first dehydrogenation reactor III, and is subjected to dehydrogenation reaction in the presence of a dehydrogenation catalyst, the reaction gas of the first dehydrogenation reactor is discharged from the side surface of the reactor III, and the distance from an outlet pipeline to the bottom of the dehydrogenation reactor accounts for 10-30% of the total height of the dehydrogenation reactor; the high-temperature steam enters a second dehydrogenation reactor IV after exchanging heat with high-temperature steam from a chamber A of a heating furnace I, a dehydrogenation reaction is carried out under the condition that a dehydrogenation catalyst exists, the reaction gas of the second dehydrogenation reactor is discharged from the side face of the reactor IV, and the distance between an outlet pipeline and the bottom of the dehydrogenation reactor accounts for 10-30% of the total height of the dehydrogenation reactor; and the reaction gas of the second dehydrogenation reactor is subjected to heat exchange with the raw material diethylbenzene through a discharge heat exchanger VI and then is sent to a rectification unit.

Detailed Description

While the present invention will be described in detail and with reference to the specific embodiments thereof, it should be understood that the following detailed description is only for illustrative purposes and is not intended to limit the scope of the present invention, as those skilled in the art will appreciate numerous insubstantial modifications and variations therefrom.

Example 1

As shown in FIG. 1, a reaction system for preparing divinylbenzene by dehydrogenating diethylbenzene (8000 hours per year of operation).

The method comprises the following steps:

the device comprises a first dehydrogenation reactor, a second dehydrogenation reactor, a heating furnace, a second dehydrogenation reactor feeding heat exchanger and a second dehydrogenation reactor discharging heat exchanger;

a raw material mixer is arranged at the bottom of the first dehydrogenation reactor; the raw material mixer is connected with the first dehydrogenation reactor;

the diethylbenzene feeding pipeline is connected with the discharge heat exchanger of the second dehydrogenation reactor and then connected with the raw material mixer; the steam feeding pipeline is connected with the heating furnace, two outlet pipelines of the heating furnace are provided, one is connected with the raw material mixer, and the other is connected with the feeding heat exchanger of the second dehydrogenation reactor and then returns to the heating furnace;

the outlet pipeline on the side surface of the first dehydrogenation reactor is connected with the feeding heat exchanger of the second dehydrogenation reactor and then is connected with the bottom of the second dehydrogenation reactor; and the outlet pipeline on the side surface of the second dehydrogenation reactor is connected with a discharge heat exchanger of the second dehydrogenation reactor and then is discharged outside.

Wherein the content of the first and second substances,

the outlet pipeline of the first dehydrogenation reactor is arranged on the side wall of the reactor, and the distance from the outlet pipeline to the bottom of the dehydrogenation reactor accounts for 20% of the total height of the dehydrogenation reactor;

the outlet pipeline of the second dehydrogenation reactor is arranged on the side wall of the reactor, and the distance from the outlet pipeline to the bottom of the dehydrogenation reactor accounts for 20% of the total height of the dehydrogenation reactor.

The reaction method for preparing the divinylbenzene by dehydrogenating the diethylbenzene comprises the following steps:

(a) after exchanging heat between the raw material diethylbenzene and the discharge of the second dehydrogenation reactor, feeding the raw material diethylbenzene into a raw material mixer, fully mixing the raw material diethylbenzene with high-temperature steam in the raw material mixer, feeding the mixture into the first dehydrogenation reactor, and carrying out dehydrogenation reaction under the conditions of a dehydrogenation catalyst and negative pressure;

(b) discharging the reaction gas of the first dehydrogenation reactor from the side surface of the reactor, exchanging heat with high-temperature steam, then entering a second dehydrogenation reactor, and carrying out dehydrogenation reaction under the conditions of a dehydrogenation catalyst and negative pressure;

(c) and the reaction gas of the second dehydrogenation reactor is discharged from the side surface of the reactor, exchanges heat with the diethylbenzene raw material and then is sent to the rectification unit.

Wherein the mass ratio of water to diethylbenzene is 1.43, the pressure of the first dehydrogenation reactor is 56Kpa, and the mixed feeding temperature of the first dehydrogenation reactor is 620 ℃;

the pressure of the second dehydrogenation reactor is 45Kpa, the feeding temperature after the second dehydrogenation reactor is mixed is 625 ℃, and the content of the divinylbenzene in the obtained dehydrogenation reaction gas reaches 24.1 percent.

And exchanging heat between the reaction gas of the second dehydrogenation reactor and the raw material diethylbenzene, heating the raw material diethylbenzene to 500 ℃, mixing the raw material diethylbenzene with water vapor, and then entering the first dehydrogenation reactor.

Example 2

A 1 ten thousand ton/year divinylbenzene unit (8000 hours per year), which is the same as example 1, except that the distance from the outlet line of the first dehydrogenation reactor to the bottom of the dehydrogenation reactor is 15% of the total height of the dehydrogenation reactor; the distance from the outlet line of the second dehydrogenation reactor to the bottom of the dehydrogenation reactor accounts for 15% of the total height of the dehydrogenation reactor;

the reaction method is the same as that of example 1, except that:

the mass ratio of water to diethylbenzene is 1.56, the pressure of a first dehydrogenation reactor is 59Kpa, and the mixed feeding temperature of the first dehydrogenation reactor is 630 ℃;

the pressure of the second dehydrogenation reactor is 50Kpa, the feeding temperature after the second dehydrogenation reactor is mixed is 635 ℃, and the content of the divinylbenzene in the obtained dehydrogenation reaction liquid reaches 26.3 percent;

and (3) exchanging heat between the reaction gas of the second dehydrogenation reactor and the raw material diethylbenzene, heating the raw material diethylbenzene to 510 ℃, mixing the raw material diethylbenzene with water vapor, and then entering the first dehydrogenation reactor.

Example 3

A 1-kiloton/year divinylbenzene unit (8000 hours per year of operation) as in example 1; the difference is only that the distance from the outlet line of the first dehydrogenation reactor to the bottom of the dehydrogenation reactor accounts for 25 percent of the total height of the dehydrogenation reactor; the distance from the outlet line of the second dehydrogenation reactor to the bottom of the dehydrogenation reactor accounts for 25 percent of the total height of the dehydrogenation reactor;

the procedure is as in example 1;

the difference lies in that:

the mass ratio of water to diethylbenzene is 1.34, the pressure of a first dehydrogenation reactor is 60Kpa, and the mixed feeding temperature of the first dehydrogenation reactor is 620 ℃;

the pressure of the second dehydrogenation reactor is 52Kpa, the feeding temperature after the second dehydrogenation reactor is mixed is 625 ℃, and the content of the divinylbenzene in the obtained dehydrogenation reaction liquid reaches 22.3 percent.

And exchanging heat between the reaction gas of the second dehydrogenation reactor and the raw material diethylbenzene, heating the raw material diethylbenzene to 500 ℃, mixing the raw material diethylbenzene with water vapor, and then entering the first dehydrogenation reactor.

Example 4

A 1-ten-thousand-ton/year divinylbenzene unit (hours per year 8400 hours), as in example 1; the difference is only that the distance from the outlet line of the first dehydrogenation reactor to the bottom of the dehydrogenation reactor accounts for 10 percent of the total height of the dehydrogenation reactor; the distance from the outlet line of the second dehydrogenation reactor to the bottom of the dehydrogenation reactor accounts for 10 percent of the total height of the dehydrogenation reactor;

the procedure is as in example 1;

the difference lies in that:

the mass ratio of water to diethylbenzene is 1.40, the pressure of a first dehydrogenation reactor is 58Kpa, and the temperature of mixed feeding of the first dehydrogenation reactor is 625 ℃;

the pressure of the second dehydrogenation reactor is 50Kpa, the feeding temperature after the second dehydrogenation reactor is mixed is 630 ℃, and the content of the divinylbenzene in the obtained dehydrogenation reaction liquid reaches 24.1 percent.

And (3) exchanging heat between the reaction gas of the second dehydrogenation reactor and the raw material diethylbenzene, heating the raw material diethylbenzene to 505 ℃, mixing the raw material diethylbenzene with water vapor, and then entering the first dehydrogenation reactor.

Example 5

A 1-ten-thousand-ton/year divinylbenzene unit (8200 hours per year), as in example 1; the difference is only that the distance from the outlet line of the first dehydrogenation reactor to the bottom of the dehydrogenation reactor accounts for 30 percent of the total height of the dehydrogenation reactor; the distance from the outlet line of the second dehydrogenation reactor to the bottom of the dehydrogenation reactor accounts for 30% of the total height of the dehydrogenation reactor;

the procedure is as in example 1;

the difference lies in that:

the mass ratio of water to diethylbenzene is 1.15, the pressure of a first dehydrogenation reactor is 62Kpa, and the mixed feeding temperature of the first dehydrogenation reactor is 618 ℃;

the pressure of the second dehydrogenation reactor is 54Kpa, the feeding temperature after the second dehydrogenation reactor is mixed is 623 ℃, and the content of the divinylbenzene in the obtained dehydrogenation reaction liquid reaches 21.1 percent.

And (3) exchanging heat between the reaction gas of the second dehydrogenation reactor and the raw material diethylbenzene, heating the raw material diethylbenzene to 495 ℃, mixing the raw material diethylbenzene with water vapor, and then entering the first dehydrogenation reactor.

The data of the embodiment shows that in the system of the application, the total pressure drop of the operating pressure of the first dehydrogenation reactor and the operating pressure of the second dehydrogenation reactor is controlled within 11Kpa, which indicates that the fluid in the reactors is uniformly distributed and the bed resistance is low, and on the other hand, indicates that the operating energy consumption of the system is low, namely the energy consumption of a subsequent compressor is greatly reduced; the operation cost is greatly saved. And the feeding and discharging of the reactor adopt a mode of downward feeding and downward discharging, so that the charging of the catalyst cannot be influenced by the inconvenience of the position of a discharging pipeline during the filling of the catalyst, and the device inspection and the filling of the catalyst are very convenient.