Method for improving catalyst activity in chloroethane production process

Abstract

The invention discloses a method for improving the activity of a catalyst in a chloroethane production process, which belongs to the field of chloroethane production and comprises the following steps: (1) introduction: introducing one path to a catalyst evaporation kettle I from a forced circulation pipeline at the bottom of a reaction kettle; (2) multiple evaporation: heating the chloroethane solution through a catalyst evaporation kettle I and a catalyst evaporation kettle II in sequence, stirring, concentrating and evaporating, condensing gas phases at the tops of the catalyst evaporation kettle I and the catalyst evaporation kettle II, and recovering crude chloroethane to a chloroethane temporary storage tank; (3) reduction: introducing chlorine into a material at the bottom of the catalyst evaporation kettle II, partially reducing ferrous chloride to restore the activity of the catalyst ferric trichloride, and then discharging into a catalyst recovery tank; the method not only effectively stabilizes the concentration of the ferric ion catalyst in the system, but also effectively reduces the influence of the activity of the catalyst on the production proportion of the polymer in the system, and effectively improves the yield of the chloroethane product.

Description

Technical Field

[0001] The invention relates to the field of ethyl chloride production, and in particular to a method for improving catalyst activity in the ethyl chloride production process. Background Art

[0002] Ethyl chloride is mainly used in the synthesis of dye intermediates, fragrance intermediates, ethyl cellulose, antibacterial agents and pesticides. Ethyl chloride is currently mainly derived from by-product recovery and synthesis methods. The recovery method mainly comes from the by-products of the synthesis of trichloroacetaldehyde and diethyl phosphite, and the synthesis method mainly comes from the reaction of ethanol with hydrochloric acid or hydrogen chloride. The key technology of the current ethylene-hydrogen chloride process for producing ethyl chloride test equipment is the control of catalyst concentration and activity in the reaction system. The catalyst ferric chloride is easily reduced to divalent iron ions, which reduces the concentration of trivalent iron ions after accumulation in the system, resulting in large fluctuations in the polymer ratio and affecting the yield of ethyl chloride products. Summary of the invention

[0003] The present invention aims at the deficiencies in the prior art and provides an evaporation circulation system, which effectively stabilizes the concentration of the trivalent iron ion catalyst in the system and more effectively reduces the influence of the catalyst activity on the polymer production ratio in the system. In order to solve the above technical problems, the present invention is solved by the following technical solutions.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for improving catalyst activity in a chloroethane production process comprises the following steps:

[0006] (1) Introduction: Lead the forced circulation pipeline at the bottom of the reactor to the catalyst evaporator 1;

[0007] (2) Multiple evaporation: The ethyl chloride solution is heated and stirred in catalyst evaporator 1 and catalyst evaporator 2 to be concentrated and evaporated, and the gas phase at the top of catalyst evaporator 1 and catalyst evaporator 2 is condensed and then the crude ethyl chloride is recovered to the ethyl chloride temporary storage tank;

[0008] (3) Reduction: Chlorine gas is introduced into the bottom material of the catalyst evaporator to partially reduce the ferrous chloride, restore the activity of the catalyst ferric chloride, and then discharge it into the catalyst recovery tank;

[0009] (4) Return: The catalyst in the catalyst recovery tank is transported to the solution at the bottom of the reactor through the catalyst recovery pump.

[0010] Preferably, a heat exchanger and a forced circulation pump are provided on the circulation pipe.

[0011] Preferably, the chlorine gas is introduced continuously at a small flow rate.

[0012] Preferably, an ethyl chloride recovery pump is connected to the output pipe at the bottom of the ethyl chloride temporary storage tank.

[0013] Preferably, the gas phase delivery pipelines of the catalyst evaporator 1 and the catalyst evaporator 2 are connected, and a condenser 1 is provided downstream of the connecting point of the delivery pipelines.

[0014] Preferably, a second condenser is provided on the output pipeline at the top of the bottom of the reactor.

[0015] Preferably, ethylene and hydrogen chloride are introduced into the reactor to react at a temperature of 50° C. to 65° C. and a pressure of 1.01 MPa to 1.5 MPa to generate ethyl chloride.

[0016] Preferably, hot water is introduced into the jackets of the catalyst evaporator 1 and the catalyst evaporator 2, and the temperature is controlled at about 60° C. and the pressure is 0.4 MPa.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The invention adds a branch line on the forced circulation system pipeline at the bottom of the reactor, draws out the catalyst mixture from the branch line, sequentially conducts two-stage evaporation and concentration, introduces chlorine into the second catalyst evaporator to reduce the catalyst, and then recycles it for use. This not only effectively stabilizes the concentration of the trivalent iron ion catalyst in the system, but also effectively reduces the influence of the catalyst activity on the polymer production ratio in the system, and effectively improves the yield of the ethyl chloride product. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 It is a schematic diagram of the process of the present invention.

[0021] Explanation of the figure numbers: 1. Reactor; 2. Heat exchanger; 3. Forced circulation pump; 4. Condenser 2; 5. Catalyst evaporator 1; 6. Catalyst evaporator 2; 7. Ethyl chloride temporary storage tank; 8. Ethyl chloride recovery pump; 9. Condenser 1; 10. Catalyst recovery tank; 11. Catalyst recovery pump; 12. Chlorine gas inlet. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below with reference to the accompanying drawings.

[0023] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be used for other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0024] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal," "lateral," "up," "down," "left," "right," "front," "back," "vertical," "horizontal," "top," "bottom," "inside," "outside," etc., indicating directions or positions, are based on the directions or positional relationships shown in the accompanying drawings, and are merely simplified descriptions for the convenience of describing the present invention, rather than indicating or implying that the device or component referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the above terms should not be understood as limitations on the present invention.

[0025] It is to be understood that the term "one" should be understood as "at least one" or "one or more," that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0026] See also Figure 1 , a method for improving catalyst activity in a process of producing ethyl chloride, comprising the following steps:

[0027] The reaction is carried out in a reactor 1, where ethylene and hydrogen chloride are introduced into an ethyl chloride solution containing 1% to 5% ferric chloride, and the reaction is carried out at a temperature of 50°C to 65°C and a pressure of 1.01MPa to 1.5MPa to generate ethyl chloride, wherein the excess hydrogen chloride completely reacts the ethylene. A heat exchanger 2 and a forced circulation pump 3 are provided on the circulation pipe, and a condenser 4 is provided on the output pipeline at the top of the bottom of the reactor.

[0028] (1) Introduction: Lead the forced circulation pipeline at the bottom of the reactor 1 all the way to the catalyst evaporator 5, and lead it out downstream of the heat exchanger 2.

[0029] (2) Multiple evaporation: The ethyl chloride solution is heated and stirred in catalyst evaporator 1 5 and catalyst evaporator 2 6 to be concentrated and evaporated. The crude ethyl chloride is condensed by condenser 9 from the gas phase at the top of catalyst evaporator 1 5 and catalyst evaporator 2 6 and recovered to ethyl chloride temporary storage tank 7. Hot water is introduced into the jackets of catalyst evaporator 1 5 and catalyst evaporator 2 6, and the temperature is controlled at about 60° C. and the pressure is 0.4 MPa. The output pipe at the bottom of ethyl chloride temporary storage tank 7 is connected to ethyl chloride recovery pump 8. The gas phase transmission pipelines of catalyst evaporator 1 5 and catalyst evaporator 2 6 are connected to the same. A condenser 9 is provided downstream of the connecting part of the conveying pipeline. Hot water is passed through the jacket of the catalyst evaporator 5 to heat it up and stir it, so as to concentrate and evaporate the ethyl chloride solution once. The evaporated liquid in the catalyst evaporator 5 enters the condenser 9 from the top of the catalyst evaporator 5 in the form of gas phase. The gas phase is condensed by the condenser 9 and then recovered to the ethyl chloride temporary storage tank 7. The residual liquid in the catalyst evaporator 5 enters the catalyst evaporator 2 6. Hot water is passed through the jacket to evaporate the residual liquid for a second time. The gas phase at the top of the catalyst evaporator 2 6 enters the condenser 9 and then is condensed and then recovered to the ethyl chloride temporary storage tank 7.

[0030] (3) Reduction: Chlorine is introduced into the bottom material of the catalyst evaporator 2 6 to partially reduce the ferrous chloride and restore the activity of the catalyst ferric chloride, and then discharged into the catalyst recovery tank 10. The catalyst evaporator 2 6 is provided with a chlorine inlet 12, and chlorine is continuously introduced at a small flow rate.

[0031] (4) Return: The catalyst in the catalyst recovery tank 10 is transported to the bottom solution of the reactor 1 by the catalyst recovery pump 11.

[0032] Experimental data:

[0033]

[0034]

[0035] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are only examples and do not limit the present invention. The purpose of the present invention has been fully and effectively achieved. The functions and structural principles of the present invention have been demonstrated and explained in the embodiments, and the embodiments of the present invention may be changed or modified without departing from the principles.

Claims

1. A method for improving catalyst activity in the production process of ethyl chloride, characterized in that: The following steps are involved: (1) Introduction: Lead the forced circulation pipeline at the bottom of the reactor (1) to the catalyst evaporator (5); (2) Multiple evaporation: The ethyl chloride solution is heated and stirred in catalyst evaporator 1 (5) and catalyst evaporator 2 (6) to be concentrated and evaporated. The top gas phases of catalyst evaporator 1 (5) and catalyst evaporator 2 (6) are condensed and the crude ethyl chloride is recovered to the ethyl chloride temporary storage tank (7); (3) Reduction: Chlorine gas is introduced into the bottom material of the catalyst evaporator (6) to partially reduce the ferrous chloride and restore the activity of the catalyst ferric chloride, which is then discharged into the catalyst recovery tank (10); (4) Return: The catalyst in the catalyst recovery tank (10) is transported to the bottom solution of the reactor (1) through the catalyst recovery pump (11).

2. The method for improving catalyst activity in a chloroethane production process according to claim 1, characterized in that: The circulation pipe is provided with a heat exchanger (2) and a forced circulation pump (3).

3. The method for improving catalyst activity in a chloroethane production process according to claim 1, characterized in that: The chlorine gas is introduced continuously at a small flow rate.

4. The method for improving catalyst activity in a chloroethane production process according to claim 1, characterized in that: An ethyl chloride recovery pump (8) is connected to the output pipe at the bottom of the ethyl chloride temporary storage tank (7).

5. The method for improving catalyst activity in a process for producing ethyl chloride according to claim 1, characterized in that: The gas phase delivery pipelines of the catalyst evaporator 1 (5) and the catalyst evaporator 2 (6) are connected, and a condenser 1 (9) is provided downstream of the connecting point of the delivery pipelines.

6. The method for improving catalyst activity in a process of producing ethyl chloride according to claim 1, characterized in that: A second condenser (4) is arranged on the output pipeline at the top of the bottom of the reaction kettle.

7. The method for improving catalyst activity in a process for producing ethyl chloride according to claim 6, characterized in that: Ethylene and hydrogen chloride are introduced into the reactor (1) to react at a temperature of 50°C to 65°C and a pressure of 1.01 MPa to 1.5 MPa to generate ethyl chloride.

8. The method for improving catalyst activity in a process for producing ethyl chloride according to claim 7, characterized in that: Hot water is introduced into the jackets of the catalyst evaporator 1 (5) and the catalyst evaporator 2 (6), and the temperature is controlled at about 60°C and the pressure is 0.4MPa.

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