CN114307902B

CN114307902B - Microchannel reactor and method for producing dinitrotoluene

Info

Publication number: CN114307902B
Application number: CN202210018778.XA
Authority: CN
Inventors: 黎孔富; 孙大明; 方明祥; 方容
Original assignee: Yidu Jovian Industry Co ltd
Current assignee: Yidu Jovian Industry Co ltd
Priority date: 2022-01-09
Filing date: 2022-01-09
Publication date: 2023-09-01
Anticipated expiration: 2042-01-09
Also published as: CN114307902A

Abstract

A microchannel reactor for producing dinitrotoluene comprises a sealing body, wherein a plurality of reaction channels and a plurality of heat exchange channels are sequentially communicated in the sealing body, and each reaction channel and each heat exchange channel are staggered. The invention has compact structure and good selectivity, the heat released in the reaction can be efficiently removed, and the production safety level is essentially improved.

Description

Microchannel reactor and method for producing dinitrotoluene

Technical Field

The invention belongs to the field of organic compound manufacturing, and particularly relates to a microchannel reactor and a method for producing dinitrotoluene.

Background

Dinitrotoluene (DNT) is a major basic chemical and is widely used in the synthetic manufacturing process of medicines, paints, dyes, rubber and other various organic chemical products. The method is commonly used for producing chemical products such as diaminotoluene, polyurethane, toluene Diisocyanate (TDI) and the like, and can also be directly used as an explosive and a propellant in the military industry and used for producing trinitrotoluene (TNT). The annual production of dinitrotoluene is under millions of tons and increases rapidly at 4-8% per year. The production method of dinitrotoluene has two ways, one is to use nitrotoluene as a raw material to carry out one-stage nitration reaction with nitric acid in mixed acid of sulfuric acid and nitric acid to obtain dinitrotoluene, and the other is to use toluene as a raw material to carry out two-stage nitration reaction to generate dinitrotoluene. Two-stage nitration is commonly used in industrial processes, where multiple dinitrotoluene isomers are typically produced. Since two isomers of 2, 4-dinitrotoluene and 2, 6-dinitrotoluene are usually used in chemical production, the target dinitrotoluene is obtained through a separation process after nitration production in industrial production. Typical production process of dinitrotoluene the main production process of dinitrotoluene today is a two-stage nitration process, specifically using toluene as raw material, reacting in a mixed acid of nitric and sulfuric acid, and nitrifying toluene into dinitrotoluene in two steps. The first step of reaction is: producing mononitrotoluene by toluene nitration; the second step is: dinitrotoluene is produced by the nitration of mononitrotoluene.

The nitration technology adopted in the production of dinitrotoluene uses flammable and explosive and highly corrosive raw materials such as toluene, nitric acid, sulfuric acid and the like in the production process, a large amount of heat is released in the reaction process, and the traditional production adopts a kettle type reactor or a tubular reactor, so that the risk is high.

Disclosure of Invention

Based on the above, the invention provides a microchannel reactor and a method for producing dinitrotoluene, which have compact structure, good selectivity, high efficiency of removal of heat released in the reaction and substantial improvement of production safety level.

In order to solve the problems, the technical scheme of the invention is as follows:

a microchannel reactor for producing dinitrotoluene comprises a sealing body, wherein a plurality of reaction channels and a plurality of heat exchange channels are sequentially communicated in the sealing body, and the reaction channels and the heat exchange channels are staggered.

The sealing body is made of submicron silicon carbide.

The sealing body comprises a plurality of reaction chips, and the reaction chips are connected into a whole in a bonding mode.

The sealing body is internally provided with temperature probes, the pipeline connected with the heat exchange flow channel is provided with PID valves, each temperature probe transmits detected signals to the controller, and each controller controls each PID valve.

The beneficial effects of the invention are as follows:

1. the invention has the advantages of compact structure, greatly reduced occupied area compared with the traditional reactor, simple and convenient operation, good selectivity and high safety.

2. The invention can realize continuous production of two-stage nitration reaction and improve the production efficiency.

3. The invention connects the basic reaction units together in parallel or in series, which can enlarge the productivity and realize the industrialized production.

Drawings

The invention is further described with reference to the accompanying drawings:

figure 1 is a schematic view of the structure of the present invention,

figure 2 is a schematic perspective view of the present invention,

fig. 3 is a schematic view of a partial cross-sectional structure of the present invention.

In the figure: a raw material A inlet 1, a raw material B inlet 2, a reaction product outlet 3, a reaction runner 4, a heat exchange medium inlet 5, a heat exchange medium outlet 6, a heat exchange runner 7, a sealing body 8, a temperature probe 9, a PID valve 10, a controller 11, a baffle 12 and a reaction hole 13.

Detailed Description

As shown in fig. 1 to 3, a microchannel reactor for producing dinitrotoluene comprises a sealing body 8, wherein a plurality of reaction channels 4 and a plurality of heat exchange channels 7 are sequentially communicated in the sealing body 8, the reaction channels 4 and the heat exchange channels 7 are all in a serpentine shape, each reaction channel 4 and each heat exchange channel 7 are alternately arranged, one end of each reaction channel 4 is communicated with a raw material A inlet 1 and a raw material B inlet 2, the other end of each reaction channel 4 is a reaction product outflow opening 3, one end of each heat exchange channel 7 is a heat exchange medium inlet 5, and the other end is a heat exchange medium outlet 6.

The working process of the invention is as follows: raw material A, B enters the reaction flow channel 4 through a pump, steam or cooling water is fed into the heat exchange flow channel 7, and reacted material flows out through a PTFE pipe connected with the product outflow port 3.

The sealing body 8 is made of submicron silicon carbide. The material has strong corrosion resistance at high temperature.

The sealing body 8 comprises a plurality of reaction chips, the reaction chips are integrally connected in a bonding mode, two sides of the reaction chips are respectively connected with a feeding cover plate and a discharging cover plate which are made of metal, and the reaction channels are not contacted with the metal.

The method for producing the sealing body 8 comprises the steps of machining a reaction groove and a heat exchange groove on a silicon carbide plate, wherein the reaction groove and the heat exchange groove are respectively positioned on the front side and the back side of the silicon carbide plate, and then overlapping a plurality of silicon carbide plates together according to the machined reaction groove and the heat exchange groove, so that two opposite reaction grooves can be combined into a reaction flow channel 4, two opposite heat exchange grooves can be combined into a heat exchange flow channel 7, and all silicon carbide plates (silicon carbide plates are reaction chips) are connected into a whole in a bonding mode. Therefore, the heat exchange efficiency can be greatly improved, and the leakage risk can be thoroughly eliminated.

A temperature probe 9 is arranged in the sealing body 8, a PID valve 10 is arranged on a pipeline connected with the heat exchange flow channel 7, each temperature probe 9 transmits detected signals to a controller 11, and each controller 11 controls each PID valve 10. The temperature probe 9 detects the temperature of the sealing body 8 in real time, and the controller 11 controls the opening of the PID valve 10 according to the temperature to control the flow of the heat exchange medium so as to regulate the reaction temperature.

The sealing bodies 8 comprise a plurality of sealing bodies 8 which are connected in parallel. In fig. 1, a plurality of sealing bodies 8 are connected in parallel, so that the throughput can be improved.

The reaction flow channel 4 is internally provided with a baffle plate 12, a plurality of reaction holes 13 are formed on the baffle plate 12, and the intervals among the reaction holes 13 are gradually shortened along the reaction flow channel 4. The partition plate 12 divides the reaction flow channel 4 into two flow channels, raw materials A, B enter the reaction flow channel 4 from the two flow channels respectively, when raw materials A, B enter the reaction flow channel 4 from the flow channels at the two sides of the partition plate 12 respectively, firstly, the raw materials are contacted and reacted at the positions of the reaction holes 13 on the partition plate 12 to consume a part of reaction heat, then, along with the shortening of the distance between the reaction holes 13, the contact frequency of the raw materials A, B is gradually increased, the heat generated by the reaction is also increased until the partition plate 12 disappears, and the raw materials A, B are fully mixed. The effect of this arrangement is that: raw materials A, B can violently react when just entering baffle 12 for reaction runner 4 inlet temperature is the highest, easily causes the runner local expansion to appear leaking because of high temperature, increases behind the baffle 12, firstly buffers the reaction of raw materials A, B, makes it can begin the reaction gradually, lets the heat that the reaction produced assemble to seal 8 center, reduces the probability that the raw materials leaked.

Claims

1. A microchannel reactor for producing dinitrotoluene, characterized by: the device comprises a sealing body (8), wherein a plurality of reaction channels (4) and a plurality of heat exchange channels (7) which are communicated in sequence are arranged in the sealing body (8), and each reaction channel (4) and each heat exchange channel (7) are arranged in a staggered manner; a partition board (12) is arranged in the reaction flow channel (4), a plurality of reaction holes (13) are formed in the partition board (12), and the intervals among the reaction holes (13) are gradually shortened along the reaction flow channel (4); the partition plate (12) divides the reaction flow path (4) into two flow paths, and the raw material A, B enters the reaction flow path (4) from the two flow paths, respectively.

2. A microchannel reactor for producing dinitrotoluene according to claim 1, wherein: the sealing body (8) is made of submicron silicon carbide.

3. A microchannel reactor for producing dinitrotoluene according to claim 2, wherein: the sealing body (8) comprises a plurality of reaction chips, and the reaction chips are connected into a whole in a bonding mode.

4. A microchannel reactor for producing dinitrotoluene according to claim 1, wherein: a temperature probe (9) is arranged in the sealing body (8), PID valves (10) are arranged on the pipelines connected with the heat exchange flow channels (7), each temperature probe (9) transmits detected signals to a controller (11), and each controller (11) controls each PID valve (10).

5. A microchannel reactor for producing dinitrotoluene according to any of claims 1 to 4, wherein: the sealing bodies (8) comprise a plurality of sealing bodies (8) which are connected in parallel.