阅读说明：本技术 气液相氯乙烯生产工艺及装置 (Gas-liquid phase chloroethylene production process and device ) 是由 高文杲 王富民 张旭斌 刘常青 王二全 王海东 于 2019-09-30 设计创作，主要内容包括：本发明提供了一种气液相氯乙烯生产工艺及装置,属于化工产品制备技术领域,包括以下步骤：原料处理,原料包括液体催化剂以及氯化氢和乙炔组成的混合气体；乙炔氢氯化反应,乙炔与氯化氢发生反应生成氯乙烯,在反应过程中通过换热器控制反应的温度；气液分离,生成的氯乙烯气体从液体催化剂中流出,液体催化剂随氯乙烯气体经过冷凝器时冷却液化回流至反应区重新作用于反应；液体催化剂回收,少量液体催化剂再次借助除沫器完成分离；乙炔转化率检测,当转化率低于95％时,更换所述液体催化剂,当转化率大于95％时使用原有液体催化剂继续进行催化作用,旨在解决现有工艺气固反应造成飞温现象和表面积碳,催化效率低的问题。(The invention provides a gas-liquid phase chloroethylene production process and a device, belonging to the technical field of chemical product preparation, and comprising the following steps: treating raw materials, wherein the raw materials comprise a liquid catalyst and mixed gas consisting of hydrogen chloride and acetylene; acetylene hydrochlorination, wherein acetylene reacts with hydrogen chloride to generate vinyl chloride, and the reaction temperature is controlled by a heat exchanger in the reaction process; gas-liquid separation, wherein the generated chloroethylene gas flows out from the liquid catalyst, and the liquid catalyst is cooled, liquefied and reflowed to the reaction area to act on the reaction again when the chloroethylene gas passes through the condenser; recovering the liquid catalyst, and separating a small amount of liquid catalyst by using the demister again; and detecting the acetylene conversion rate, replacing the liquid catalyst when the conversion rate is lower than 95%, and continuously performing catalytic action by using the original liquid catalyst when the conversion rate is higher than 95%, so as to solve the problems of temperature runaway phenomenon, surface carbon deposition and low catalytic efficiency caused by gas-solid reaction in the prior art.)

1. The gas-liquid phase chloroethylene production process is characterized by comprising the following steps of:

processing raw materials, wherein the raw materials comprise a liquid catalyst and mixed gas consisting of hydrogen chloride and acetylene;

acetylene hydrochlorination, wherein under the action of the liquid catalyst, acetylene reacts with hydrogen chloride to generate vinyl chloride, and the reaction temperature is controlled by a heat exchanger in the reaction process;

gas-liquid separation, wherein the generated chloroethylene gas flows out from the liquid catalyst, and the liquid catalyst is cooled, liquefied and reflowed to the reaction area to act on the reaction again when the chloroethylene gas passes through the condenser;

recovering the liquid catalyst, and separating a small amount of liquid catalyst again by means of a demister after gas-liquid separation;

and detecting the acetylene conversion rate, replacing the liquid catalyst when the conversion rate is lower than 95%, and continuing the catalytic action by using the original liquid catalyst when the conversion rate is higher than 95%.

2. The process for the production of vinyl chloride in gas-liquid phase according to claim 1, wherein the molar ratio of acetylene to hydrogen chloride is 1.0 to 1.2: 1.

3. The process for the production of vinyl chloride in the gas-liquid phase as claimed in claim 1, wherein the initial addition temperature of the liquid catalyst is 100-120 ℃.

4. The process for the production of vinyl chloride in the gas-liquid phase as claimed in claim 1, wherein the heat exchanger controls the reaction temperature at 130-160 ℃.

5. The gas-liquid phase vinyl chloride production process of claim 1, wherein the liquid catalyst is one of imidazole hydrochloride, N-methyl pyrrolidone hydrochloride, choline chloride or quaternary phosphonium salt; the active component of the liquid catalyst is one of cupric chloride, cuprous chloride, stannic chloride and ruthenium trichloride.

6. Realize device of gas-liquid phase chloroethylene production technology, its characterized in that, including reation kettle, reation kettle is equipped with:

the liquid catalyst inlet is positioned in the middle of the reaction kettle;

the liquid catalyst outlet is positioned at the bottom of the reaction kettle;

the mixed gas inlet is positioned at the bottom of the reaction kettle;

the reaction zone is provided with the heat exchanger;

the gas-liquid separation zone is positioned above the reaction zone and is provided with a condenser;

the demister is arranged above the condenser and used for adsorbing a small amount of the liquefaction catalyst; and

and the exhaust port is positioned at the top of the reaction kettle and is used for exhausting the generated vinyl chloride to obtain crude vinyl chloride gas.

7. The apparatus for producing vinyl chloride in gas-liquid phase as claimed in claim 6, wherein a gas distributor is further provided in said reaction vessel for uniformly distributing the mixed gas introduced through the mixed gas inlet.

8. The apparatus for producing vinyl chloride in a gas-liquid phase according to claim 6, wherein said heat exchanger is one of a shell-and-tube heat exchanger, a plate heat exchanger, and a shell-and-tube heat exchanger.

9. The gas-liquid phase vinyl chloride production apparatus of claim 7, wherein the gas distributor comprises:

a circular plate provided with a plurality of air passing holes; and

mix the pipe support, including ring canal and one end intercommunication ring canal and intercommunication department along ring canal circumferencial direction equipartition, the other end intercommunication and intercommunication department lie in a plurality of inner tubes in the ring canal centre of a circle, the ring canal is equipped with the air inlet, the air inlet is used for the mist to get into, be equipped with a plurality of micropores on ring canal and the inner tube, the mist warp micropore and get into the reaction zone behind the gas passing hole, the micropore lies in the both sides of ring canal and inner tube lower part, the gas passing hole aperture is less than the micropore aperture.

10. The apparatus for producing vinyl chloride in gas-liquid phase according to claim 9, wherein said circular plate is fixedly attached to the inner wall of the reaction vessel, said circular plate, the loop pipe and the inner pipe are horizontally disposed, and said air passing holes are arranged on said circular plate in a plurality of concentric circles having gradually decreasing radii.

Technical Field

The invention belongs to the technical field of chemical product preparation, and particularly relates to a gas-liquid phase chloroethylene production process and a gas-liquid phase chloroethylene production device.

Background

Vinyl chloride, also known as vinyl chloride, is one of the halogenated hydrocarbons, an important raw material for the plastics industry, mainly used for the production of polyvinyl chloride resins (i.e. PVC, the most productive general plastic in the world); or can be copolymerized with vinyl acetate, butadiene, acrylonitrile, acrylate, vinylidene chloride and the like to manufacture adhesives, coatings, food packaging materials, building materials and the like; the characteristic of low boiling point can be used as a freezer; it can also be used as extractant for dye and perfume.

At present, the industrial synthesis method of vinyl chloride monomer mainly comprises an acetylene hydrochlorination method and an ethylene oxychlorination method, the production capacity of Chinese PVC in 2017 reaches about 2300 million tons, about 80% of PVC production comes from an acetylene route and accounts for about 40% of the global PVC productivity.

Compared with gas-solid phase reaction, the gas-liquid phase reaction has good mass and heat transfer effects, so that reactants are fully contacted, the carbon deposition phenomenon can be effectively avoided, the catalytic efficiency of the catalyst is improved, and the occurrence of side reactions is reduced. In the traditional gas-solid phase process, a tubular reactor is adopted, a catalyst is filled in a tube side, and a heat exchange medium is filled in a shell side. Catalyst change needs the parking operation, and is very inconvenient, increases operating cost, influences normal production, still causes the potential safety hazard that the material was revealed and is caused easily, is the big taboo of chemical enterprise's production.

Moreover, in recent years, with the upgrading of product consumption, downstream plastic processing puts new requirements on the variety and quality of polyvinyl chloride, so the improvement of the production process of vinyl chloride is a problem to be solved by vinyl chloride production enterprises.

Disclosure of Invention

The invention aims to provide a gas-liquid phase chloroethylene production process and a gas-liquid phase chloroethylene production device, and aims to solve the problems of temperature runaway phenomenon, surface carbon deposition and low catalytic efficiency caused by gas-solid reaction in the existing production process.

In order to achieve the purpose, the invention adopts the technical scheme that: provides a gas-liquid phase chloroethylene production process, which comprises the following steps:

processing raw materials, wherein the raw materials comprise a liquid catalyst and mixed gas consisting of hydrogen chloride and acetylene;

acetylene hydrochlorination, wherein under the action of the liquid catalyst, acetylene reacts with hydrogen chloride to generate vinyl chloride, and the reaction temperature is controlled by a heat exchanger in the reaction process;

gas-liquid separation, wherein the generated chloroethylene gas flows out from the liquid catalyst, and the liquid catalyst is cooled, liquefied and reflowed to the reaction area to act on the reaction again when the chloroethylene gas passes through the condenser;

recovering the liquid catalyst, and separating a small amount of liquid catalyst again by means of a demister after gas-liquid separation;

and detecting the acetylene conversion rate, replacing the liquid catalyst when the conversion rate is lower than 95%, and continuing the catalytic action by using the original liquid catalyst when the conversion rate is higher than 95%.

As another example herein, the molar ratio of acetylene to hydrogen chloride is 1.0 to 1.2: 1.

As another example herein, the initial addition temperature of the liquid catalyst is 100-120 ℃.

As another embodiment of the present application, the heat exchanger controls the reaction temperature at 130-160 ℃.

As another embodiment herein, the liquid catalyst is one of imidazole hydrochloride, nitrogen methyl pyrrolidone hydrochloride, choline chloride or quaternary phosphonium salt; the active component of the liquid catalyst is one of cupric chloride, cuprous chloride, stannic chloride and ruthenium trichloride.

Realize the device of gas-liquid phase chloroethylene production technology, including reation kettle, reation kettle is equipped with:

the liquid catalyst inlet is positioned in the middle of the reaction kettle;

the liquid catalyst outlet is positioned at the bottom of the reaction kettle;

the mixed gas inlet is positioned at the bottom of the reaction kettle;

the reaction zone is provided with the heat exchanger;

the gas-liquid separation zone is positioned above the reaction zone and is provided with a condenser;

the demister is arranged above the condenser and used for adsorbing a small amount of the liquefaction catalyst; and

and the exhaust port is positioned at the top of the reaction kettle and is used for exhausting the generated vinyl chloride to obtain crude vinyl chloride gas.

As another embodiment of this application, still be equipped with gas distributor in the reation kettle for the equipartition is through the mist that the mist import got into.

As another embodiment of the application, the heat exchanger is one of a shell and tube heat exchanger, a plate heat exchanger and a shell and tube heat exchanger.

As another embodiment of the present application, the gas distributor includes:

a circular plate provided with a plurality of air passing holes; and

mix the pipe support, including ring canal and one end intercommunication ring canal and intercommunication department along ring canal circumferencial direction equipartition, the other end intercommunication and intercommunication department lie in a plurality of inner tubes of ring canal centre of a circle, the ring canal is equipped with the air inlet, the air inlet is used for the mist to get into, be equipped with a plurality of micropores on ring canal and the inner tube, the mist warp micropore and get into the reaction zone behind the gas pocket, the micropore lies in ring canal and inner tube lower part both sides, and the mist of being convenient for makes progress the reflux process gas pocket from the lower part, avoids the emergence of ditch stay phenomenon, it is less than the micropore aperture to cross the.

As another embodiment of the application, the circular plate is fixedly connected with the inner wall of the reaction kettle, the circular plate, the ring pipe and the inner pipe are all horizontally arranged, and the air passing holes are arranged on the circular plate to form a plurality of concentric circles with gradually reduced radiuses.

The gas-liquid phase chloroethylene production process and the gas-liquid phase chloroethylene production device have the beneficial effects that:

(1) compared with a fixed bed reactor, the method avoids the phenomenon of local temperature runaway, avoids carbon deposition on the surface of the catalyst, and improves the catalytic efficiency of the catalyst.

(2) The reaction is carried out in the tube pass of the heat exchanger, so that the reaction heat can be removed in time, the reaction risk is reduced, and the production safety is improved.

(3) Compared with the traditional method for producing vinyl chloride by mercury catalysis, the method for producing vinyl chloride by using the mercury-free liquid catalyst avoids environmental pollution and accords with the national industrialization policy.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed for the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a reaction kettle according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a circular plate according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a mixing pipe rack provided in an embodiment of the present invention.

In the figure: 1. the device comprises a reaction kettle, 2, a liquid catalyst inlet, 3, a liquid catalyst outlet, 4, a mixed gas inlet, 5, a heat exchanger, 6, a condenser, 7, a demister, 8, an exhaust port, 9, a gas distributor, 10, a circular plate, 11, a ring pipe, 12, an inner pipe, 13 and a gas passing hole.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1 to 3 together, the process for producing vinyl chloride in gas-liquid phase according to the present invention will now be described, which includes the following steps:

processing raw materials, wherein the raw materials comprise a liquid catalyst and mixed gas consisting of hydrogen chloride and acetylene;

acetylene hydrochlorination, wherein under the action of the liquid catalyst, acetylene reacts with hydrogen chloride to generate vinyl chloride, and the reaction temperature is controlled by a heat exchanger 5 in the reaction process;

gas-liquid separation, wherein the generated chloroethylene gas flows out from the liquid catalyst, and the liquid catalyst is cooled, liquefied and reflowed to the reaction area to act on the reaction again when the chloroethylene gas passes through the condenser 6;

recovering the liquid catalyst, and separating a small amount of liquid catalyst by the demister 7 after gas-liquid separation;

and detecting the acetylene conversion rate, replacing the liquid catalyst when the conversion rate is lower than 95%, and continuing the catalytic action by using the original liquid catalyst when the conversion rate is higher than 95%.

Compared with the prior art, the vinyl chloride production process provided by the embodiment of the invention comprises the following steps: 1) compared with a fixed bed reactor, the method avoids the phenomenon of local temperature runaway, avoids carbon deposition on the surface of the catalyst, and improves the catalytic efficiency of the catalyst. 2) The reaction is carried out in the tube pass of the heat exchanger 5, so that the reaction heat can be removed in time, the reaction risk is reduced, and the production safety is improved. 3) Compared with the traditional method for producing vinyl chloride by mercury catalysis, the method for producing vinyl chloride by using the mercury-free liquid catalyst avoids environmental pollution and accords with the national industrialization policy.

As an embodiment of the vinyl chloride production process provided by the present invention, the molar ratio of acetylene to hydrogen chloride is 1.0 to 1.2: 1.

As an embodiment of the vinyl chloride production process provided by the present invention, the initial addition temperature of the liquid catalyst is 100-120 ℃.

As an embodiment of the vinyl chloride production process provided by the present invention, the heat exchanger 5 controls the reaction temperature at 130-160 ℃.

As an embodiment of the vinyl chloride production process provided by the present invention, the liquid catalyst is one of imidazole hydrochloride, nitrogen methyl pyrrolidone hydrochloride, choline chloride or quaternary phosphonium salt; the active component of the liquid catalyst is one of cupric chloride, cuprous chloride, stannic chloride and ruthenium trichloride.

In the embodiment, a liquid catalyst is heated to 100-120 ℃, and is added into a reaction kettle 1 from the middle lower part through a liquid catalyst pipeline until reaching the position of a liquid catalyst inlet 2; dehydrating and impurity-removing hydrogen chloride gas and acetylene gas, mixing, and adding the mixture into the reaction kettle 1 from the bottom of the reaction kettle 1 through a mixed gas pipeline and a gas distributor 9; wherein the liquid catalyst is a mercury-free catalyst; wherein the molar ratio of the acetylene gas to the hydrogen chloride gas is 1.0-1.2: 1.

in a reaction kettle 1, under the action of a liquid catalyst, acetylene reacts with hydrogen chloride to generate vinyl chloride, so that a gas mixture mainly containing vinyl chloride is obtained, and the reaction temperature is controlled to be 130-160 ℃ through a heat exchanger 5 in the reaction process.

The gas mixture mainly containing the chloroethylene obtained by the reaction carries a small amount of liquid catalyst volatilized into gas state to move upwards, and after being condensed by the condenser 6, the small amount of liquid catalyst volatilized into gas state is converted into liquid state and falls back to the lower part of the reaction kettle 1 to continue to participate in the reaction; then further upwards through a demister 7 to remove a small amount of liquid catalyst again to obtain vinyl chloride crude gas, and the vinyl chloride crude gas is discharged to the subsequent process through a product pipeline.

When the conversion rate of acetylene is detected to be lower than 95% by sampling in a product pipeline, the activity of the liquid catalyst is reduced, a small amount of liquid catalyst to be treated is discharged from a liquid catalyst outlet 3, and fresh liquid catalyst with the same mass is added from a liquid catalyst inlet 2 to keep the high activity of the liquid catalyst;

wherein the liquid catalyst to be treated can be reused as the liquid catalyst after being regenerated.

The device for realizing the gas-liquid phase chloroethylene production process comprises a reaction kettle 1, wherein the reaction kettle 1 is provided with:

the liquid catalyst inlet 2 is positioned in the middle of the reaction kettle 1;

a liquid catalyst outlet 3 positioned at the bottom of the reaction kettle 1;

the mixed gas inlet 4 is positioned at the bottom of the reaction kettle 1;

the reaction zone is provided with the heat exchanger 5;

the gas-liquid separation zone is positioned above the reaction zone and is provided with a condenser 6;

a demister 7 arranged above the condenser 6 and used for adsorbing a small amount of liquefaction catalyst; and

and a gas outlet 8, provided at the top of the reaction tank 1, for discharging the generated vinyl chloride to obtain a crude vinyl chloride gas.

Referring to fig. 1, the liquid catalyst inlet 2 is located between the heat exchanger 5 and the condenser 6 near the heat exchanger 5, and the liquid level of the catalyst is located below or flush with the lower edge of the liquid catalyst inlet 2 during the reaction.

And a liquid catalyst outlet 3 for discharging the liquid catalyst to be treated having a decreased activity.

A gas outlet 8 is provided at the top of the reaction tank 1 for discharging the generated vinyl chloride to obtain a crude vinyl chloride gas.

The condenser 6 is positioned at the upper part of the heat exchanger 5 and the liquid catalyst inlet 2, so that the liquid catalyst carried by the reaction product chloroethylene crude product falls back after condensation, and continuously participates in the reaction to complete gas-liquid separation.

A demister 7 is disposed at the upper portion of the reaction tank 1 and the upper portion of the condenser 6 to further remove the liquid catalyst entrained in the crude vinyl chloride.

As an embodiment of the vinyl chloride production process provided by the present invention, a gas distributor 9 is further disposed in the reaction kettle 1 for uniformly distributing the mixed gas entering through the mixed gas inlet 4.

Referring to fig. 1 to 3, the gas distributor 9 is located at the lower portion of the reaction kettle 1, and is located at the lower portion of the heat exchanger 5, and is used for uniformly distributing the mixed gas of hydrogen chloride and acetylene in the reaction kettle 1, and uniformly contacting the mixed gas with the liquid catalyst, so as to avoid the occurrence of the local over-high temperature during the reaction process.

The gas distributor 9 is very close to the heat exchanger 5, so that the reaction is carried out in the tube pass of the heat exchanger 5, the reaction heat is removed in time, the safety of the reaction is improved, and the occurrence of side reactions is reduced.

As an embodiment of the vinyl chloride production process provided by the present invention, the heat exchanger 5 is one of a shell-and-tube heat exchanger, a plate heat exchanger, and a shell-and-tube heat exchanger.

As an embodiment of the vinyl chloride production process provided in the present invention, please refer to fig. 2 to 3 that the gas distributor 9 includes:

a circular plate 10 provided with a plurality of air passing holes 13; and

mixing tube support, including ring canal 11 and one end intercommunication ring canal 11 and intercommunication department along 11 circumferencial direction equipartitions of ring canal, the other end intercommunication each other and intercommunication department are located a plurality of inner tubes 12 of the ring canal 11 centre of a circle, ring canal 11 is equipped with the air inlet, the air inlet is used for the mist to get into, be equipped with a plurality of micropores on ring canal 11 and the inner tube 12, the mist passes through the micropore and get into the reaction zone behind the gas passing hole 13. The micropores are positioned at two sides of the lower part of the ring pipe and the inner pipe, so that the mixed gas can conveniently flow back upwards from the lower part and pass through the air holes 13, and the phenomenon of ditch retention is avoided. The aperture of the air passing hole 13 is smaller than that of the micropore. The micro-holes are arranged at positions which are inclined downwards by 30-60 degrees in the horizontal plane.

The mixed gas inlet 4 is communicated with the air inlet of a ring pipe 11 of the gas distributor 9 and is used for adding the mixed gas of hydrogen chloride and acetylene into the reaction kettle 1.

As an embodiment of the vinyl chloride production process provided by the present invention, the circular plate 10 is fixedly connected to the inner wall of the reaction vessel 1, the circular plate 10, the annular pipe 11 and the inner pipe 12 are all horizontally disposed, and the air holes 13 are arranged on the circular plate 10 to form a plurality of concentric circles with gradually reduced radius.

The gas distributor 9 is divided into an upper layer and a lower layer, a circular plate 10 is arranged on the upper layer, and a plurality of uniformly distributed gas passing holes 13 are formed in the circular plate 10; below is a loop 11 and an inner tube 12, the outer edge of the circular plate 10 abutting the inner wall of the reactor 1.

Be equipped with liquid catalyst export 3, coolant inlet, coolant export, liquid catalyst import 2, gas vent 8 on the outer wall of reation kettle 1, reation kettle 1 is inside from supreme gas distributor 9, heat exchanger 5, condenser 6, demister 7 of being equipped with in proper order down.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.