A chlorinated polyethylene production apparatus

Abstract

The utility model provides a kind of chlorinated polyethylene production device, by reverse osmosis unit to hydrogen chloride tail gas absorption liquid is concentrated to the concentration required for chlorinated polyethylene preparation initial stage as hydrochloric acid solution phase use, with the continuous performance of reaction, the hydrochloric acid generated by chlorination reaction is collected in hydrochloric acid tank one, when concentration is too high, can be adjusted dilution by reverse osmosis unit dilution water, and switch reverse osmosis unit is used to output concentration dilute hydrochloric acid by-product outward, achieve in initial stage dilute hydrochloric acid solution supply and the dilute hydrochloric acid by-product output of stable stage, waste acid formed by tail gas is reasonably utilized and wastewater discharge is reduced.

Description

Technical Field

[0001] This utility model relates to the chemical industry, specifically to a chlorinated polyethylene production apparatus. Background Technology

[0002] Chemical reactions often involve the generation of gases. For some acidic tail gases, such as hydrogen chloride, absorption can lead to the formation of acidic wastewater, burdening wastewater treatment. For instance, in the esterification reaction of chlorosilanes, a significant amount of hydrogen chloride is generated as a byproduct. If this is not removed through absorption, it will affect the reaction conversion rate; furthermore, the treatment of the acidic wastewater after absorption must be considered.

[0003] Chlorinated polyethylene (CPE) can usually be produced by suspension method, especially hydrochloric acid method. The preparation process is highly efficient when dilute hydrochloric acid of appropriate concentration is used as the aqueous phase. The resulting CPE has high cleanliness, good appearance and uniform chlorine content. If hydrogen chloride tail gas is used to prepare CPE, it is expected to have synergistic effects and reduce environmental pressure. Utility Model Content

[0004] This invention proposes a chlorinated polyethylene production device to make reasonable use of hydrogen chloride tail gas and reduce environmental pressure.

[0005] The technical solution of this utility model is implemented as follows: A chlorinated polyethylene production apparatus includes a preparation unit and a hydrochloric acid supply unit; wherein: The preparation unit includes a chlorination reactor and a separation reactor connected together. The separation reactor is used to separate the reaction products and the solution. The lower part of the separation reactor is equipped with an acid outlet pipe connected to a hydrochloric acid tank. The lower part of the hydrochloric acid tank is equipped with a hydrochloric acid inlet pipe connected to the chlorination reactor. The hydrochloric acid supply unit includes an absorber and a reverse osmosis unit. The absorber is used to absorb hydrogen chloride gas with water. The outlet of the absorber is connected to the inlet of the reverse osmosis unit. The concentrate output end of the reverse osmosis unit is equipped with a concentrate pipe and a hydrochloric acid delivery pipe, respectively. The concentrate pipe is connected to the hydrochloric acid tank. The desalination output end of the reverse osmosis unit is equipped with a water supply pipe, which is connected to the hydrochloric acid inlet pipe. The concentrate pipe, water supply pipe, and hydrochloric acid delivery pipe are each equipped with a control valve.

[0006] Furthermore, a filter unit is provided inside the acid discharge pipe.

[0007] Furthermore, the separation vessel is equipped with an alkali solution pipe and / or a water washing pipe.

[0008] Preferably, the freshwater output end of the reverse osmosis unit is further provided with a drain pipe, which is connected to the water washing pipe.

[0009] Furthermore, the upper part of the chlorination reactor is equipped with a chlorine gas pipe and a nitrogen gas pipe.

[0010] Furthermore, a pump is provided on the feed pipe; and / or, the outlet of the absorber is connected to the feed end of the reverse osmosis unit via a hydrochloric acid tank and a pump.

[0011] Furthermore, the inlet of the absorber is connected to the chlorosilane alcoholysis device; the chlorosilane alcoholysis device includes an alcoholysis reactor and a condenser connected to its top; the condenser is provided with a return line connected to the alcoholysis reactor; the inlet of the absorber is connected to the return line.

[0012] Compared with the prior art, the beneficial effects of this utility model are as follows: This invention uses a reverse osmosis unit to concentrate the hydrogen chloride tail gas absorbent to the required concentration for use as a hydrochloric acid solution phase in the initial stage of chlorinated polyethylene preparation. As the reaction continues, the hydrochloric acid generated by the chlorination reaction is collected in a hydrochloric acid tank. When the concentration is too high, it can be adjusted and diluted by desalination water through the reverse osmosis unit. The reverse osmosis unit is then switched to output concentrated dilute hydrochloric acid byproducts, thus realizing the supply of dilute hydrochloric acid solution in the initial stage and the output of dilute hydrochloric acid byproducts in the stable stage. This makes reasonable use of the waste acid formed by the tail gas and reduces wastewater discharge. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 A schematic diagram of a chlorinated polyethylene production apparatus provided by this utility model.

[0015] Figure 2 This is a schematic diagram of the overall production apparatus for preparing chlorinated polyethylene using the tail gas from the alcoholysis reaction of silane chloride according to this invention.

[0016] The attached figures are labeled as follows: A1, Absorber; AT1, Absorber Tower; C1, Condenser; K1, Valve 1; K2, Valve 2; K3, Valve 3; L1, Concentrate Pipe; L2, Water Makeup Pipe; L3, Drainage Pipe; L4, Hydrochloric Acid Delivery Pipe; L5, Hydrochloric Acid Feed Pipe; L6, Chlorine Pipe; L7, Nitrogen Pipe; L8, Alkali Pipe; L9, Washing Pipe; L10, CPE Outlet Pipe; L11, Acid Outlet Pipe; L12, Tail Gas Pipe; P1, Pump 1; P2, Pump 2; R1, Chlorination Reactor; R2, Separation Reactor; R3, Alcohololysis Reactor; RO1, Reverse Osmosis Unit; S1, Hydrochloric Acid Tank 1; S2, Hydrochloric Acid Tank 2. Detailed Implementation

[0017] The technical solution of this utility model will be clearly and completely described below with reference to its embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0018] Reference Figure 1 This embodiment provides a chlorinated polyethylene production apparatus, including a preparation unit and a hydrochloric acid supply unit; wherein: The preparation unit includes a chlorination reactor R1 and a separation reactor R2 connected together. The separation reactor R2 is used to separate the reaction products and the solution. The lower part of the separation reactor R2 is equipped with an acid discharge pipe L11 connected to the hydrochloric acid tank S1. The lower part of the hydrochloric acid tank S1 is equipped with a hydrochloric acid feed pipe L5 connected to the chlorination reactor R1. The hydrochloric acid supply unit includes an absorber A1 and a reverse osmosis unit RO1. The absorber A1 is used to absorb hydrogen chloride gas with water. The outlet of the absorber A1 is connected to the inlet of the reverse osmosis unit RO1. The concentrated liquid output end of the reverse osmosis unit RO1 is provided with a concentrated liquid pipe L1 and a hydrochloric acid delivery pipe L4. The concentrated liquid pipe L1 is connected to the hydrochloric acid tank S1. The fresh water output end of the reverse osmosis unit RO1 is provided with a water supply pipe L2 and a drain pipe L3. The water supply pipe L2 is connected to the hydrochloric acid inlet pipe L5. The concentrated liquid pipe L1, the water supply pipe L2, and the hydrochloric acid delivery pipe L4 are respectively provided with valve K1, valve K2, and valve K3.

[0019] In the above embodiment, the hydrogen chloride tail gas absorbent is concentrated to the required concentration by the reverse osmosis unit RO1 and then transferred to the chlorination reactor R1 through the hydrochloric acid feed pipe L5 for use as the hydrochloric acid solution phase in the initial stage of chlorinated polyethylene preparation. As the reaction continues, the hydrochloric acid generated by the chlorination reaction is collected in the hydrochloric acid tank S1. When the hydrochloric acid concentration is too high, valve K2 can be opened to adjust and dilute it with the desalinated water output from the reverse osmosis unit RO1. At the same time, valve K1 is closed and valve K3 is opened. The reverse osmosis unit RO1 is used to output the concentrated dilute hydrochloric acid by-product, realizing the supply of dilute hydrochloric acid solution in the initial stage and the output of dilute hydrochloric acid by-product in the stable stage, making reasonable use of the waste acid formed by the tail gas and reducing wastewater discharge.

[0020] In the above embodiments, the absorber A1 can be a commonly used absorber, preferably a falling film absorber, which obtains a dilute hydrochloric acid solution by introducing air and water at the top and discharging the absorbent at the bottom.

[0021] In a preferred embodiment, the acid discharge pipe L11 is equipped with a filter unit, such as a corrosion-resistant filter screen installed at the outlet of the chlorination reactor R1 side wall to avoid clogging the pipe.

[0022] In a preferred embodiment, the upper part of the separation vessel R2 is also connected to an alkali solution pipe L8 and a water washing pipe L9. After the hydrochloric acid solution in the vessel is discharged through the acid discharge pipe L11, the CPE can be washed through the alkali solution pipe L8 and the water washing pipe L9, and then discharged from the CPE collection pipe 10.

[0023] In a preferred embodiment, the freshwater output end of the reverse osmosis unit RO1 is also provided with a drain pipe L3, which can be connected to the water washing pipe L9 (not shown in the figure). In the initial stage of preparation, the freshwater discharged from the reverse osmosis can be used for washing the CPE to reduce water consumption.

[0024] In a preferred embodiment, the chlorination reactor R1 is equipped with a chlorine gas pipe L6 and a nitrogen gas pipe L7 at its upper part. The chlorine gas pipe L6 is used to introduce chlorine gas to react with the added polyethylene; after the reaction is completed, nitrogen gas can be introduced through the nitrogen gas pipe L7 to pressurize the material in the reactor into the separation reactor R2, so as to reduce the escape of gas.

[0025] In a preferred embodiment, the top of the chlorination reactor R1 is provided with a tail gas pipe L12, which is further connected to the gas inlet of the absorber A1 for absorbing the small amount of hydrogen chloride that escapes.

[0026] In a preferred embodiment, to improve stability and production efficiency, a pump P1 is provided on the feed pipe L5; the outlet of the absorber A1 is connected to the feed end of the reverse osmosis unit RO1 via the hydrochloric acid tank S2 and the pump P2.

[0027] In a preferred embodiment, such as Figure 2 As shown, when the tail gas from the chlorosilane alcoholysis unit is used to prepare chlorinated polyethylene, the inlet of the absorber A1 is connected to the chlorosilane alcoholysis unit. The chlorosilane alcoholysis unit includes an alcoholysis reactor R3 and a condenser C1 connected to its top. The condenser C1 is connected to the alcoholysis reactor R3 via a reflux line. The inlet of the absorber A1 is connected to the reflux line. During the chlorosilane alcoholysis process, chlorosilanes react with alcohols to produce silanols and hydrogen chloride. Taking the reaction of trimethylchlorosilane with methanol as an example, methoxytrimethylsilane and hydrogen chloride are produced. Since hydrogen chloride has a low boiling point, the gas phase can be condensed and separated by the condenser C1 and enter the absorber A1. A small amount of refluxed liquid phase is recycled back into the alcoholysis reactor R3.

[0028] In the above embodiments, chlorosilane alcoholysis and chlorinated polyethylene production coexist in the applicant's production area. The combination of the chlorosilane alcoholysis unit and the chlorinated polyethylene production unit will meet the actual conditions and achieve synergistic efficiency.

[0029] It is understood that the materials of the components used in the above devices or units can be selected according to the requirements of corrosion protection, and commonly used instruments, meters or valves can also be selected or added according to the operational requirements. All of the above are within the design scope of this solution and will not be elaborated here.

[0030] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A chlorinated polyethylene production apparatus, characterized in that, Includes a preparation unit and a hydrochloric acid supply unit; wherein: The preparation unit includes a chlorination reactor (R1) and a separation reactor (R2) connected together. The separation reactor (R2) is used to separate the reaction products and the solution. The lower part of the separation reactor (R2) is equipped with an acid discharge pipe (L11) connected to the first hydrochloric acid tank (S1). The lower part of the first hydrochloric acid tank (S1) is equipped with a hydrochloric acid feed pipe (L5) connected to the chlorination reactor (R1). The hydrochloric acid supply unit includes an absorber (A1) and a reverse osmosis unit (RO1). The absorber (A1) is used to absorb hydrogen chloride gas with water. The outlet of the absorber (A1) is connected to the inlet of the reverse osmosis unit (RO1). The concentrated liquid output end of the reverse osmosis unit (RO1) is provided with a concentrated liquid pipe (L1) and a hydrochloric acid delivery pipe (L4). The concentrated liquid pipe (L1) is connected to the hydrochloric acid tank (S1). The fresh water output end of the reverse osmosis unit (RO1) is provided with a water supply pipe (L2) and connected to the hydrochloric acid feed pipe (L5). The concentrated liquid pipe (L1), the water supply pipe (L2), and the hydrochloric acid delivery pipe (L4) are each provided with control valves.

2. The apparatus as claimed in claim 1, characterized in that, The acid discharge pipe (L11) is equipped with a filter unit.

3. The apparatus as described in claim 1, characterized in that, The separation vessel (R2) is equipped with an alkali solution pipe (L8) and / or a water washing pipe (L9).

4. The apparatus as described in claim 3, characterized in that, The freshwater output end of the reverse osmosis unit (RO1) is also equipped with a drain pipe (L3), which is connected to the water washing pipe (L9).

5. The apparatus as claimed in claim 1, characterized in that, The upper part of the chlorination reactor (R1) is equipped with a chlorine gas pipe (L6) and a nitrogen gas pipe (L7).

6. The apparatus as claimed in claim 1, characterized in that, Pump 1 (P1) is provided on the feed pipe (L5); and / or, the outlet end of the absorber (A1) is connected to the feed end of the reverse osmosis unit (RO1) via hydrochloric acid tank 2 (S2) and pump 2 (P2).

7. The apparatus as claimed in claim 1, characterized in that, The inlet of the absorber (A1) is connected to the chlorosilane alcoholysis device; the chlorosilane alcoholysis device includes an alcoholysis reactor (R3) and a condenser (C1) connected to its top; the condenser (C1) is provided with a reflux line connected to the alcoholysis reactor (R3); the inlet of the absorber (A1) is connected to the reflux line.

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