A chlorinated polyethylene production process by-product hydrochloric acid concentration system

Abstract

The present application belongs to the field of hydrochloric acid concentration equipment, and particularly relates to a chlorinated polyethylene production process by-product hydrochloric acid concentration system, which comprises a resolving tower and a condensing section dilute hydrochloric acid input tank, the condensing section dilute hydrochloric acid input tank is connected with an absorption tank and a dilute hydrochloric acid buffer tank, the output end of the dilute hydrochloric acid buffer tank is connected with the liquid input end of the resolving tower, the gas input end of the resolving tower is connected with a reboiler, the gas output end of the resolving tower is connected with the absorption tank, and the output end of the absorption tank is connected with a concentrated hydrochloric acid storage tank. The present application divides the condensed dilute hydrochloric acid generated in the condensing section of the chlorinated polyethylene production process into three parts, reduces the types of system raw materials, reduces the difficulty of material preparation, increases the concentration of dilute hydrochloric acid through the resolving formed hydrogen chloride, improves the concentration of hydrochloric acid, and improves the economic value of the product.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of hydrochloric acid concentration equipment, and particularly relates to a hydrochloric acid concentration system for by-product hydrochloric acid in a chlorinated polyethylene production process. BACKGROUND

[0002] In the production process of chlorinated polyethylene, chlorine gas is introduced into a working liquid in which polyvinyl chloride powder is suspended, so as to form chlorinated polyethylene powder. The working liquid is added with hydrochloric acid and additives such as catalysts and dispersants. A large amount of HCL and water vapor is generated in the process of introducing chlorine gas. The working liquid can be recycled due to the presence of additives. However, a certain amount of water is used in the process of cleaning the product powder, resulting in dilution of the working liquid. Therefore, in order to save costs, the additives need to be added to the working liquid again.

[0003] The HCL and water vapor generated in the production process are condensed to form dilute hydrochloric acid. The dilute hydrochloric acid product has poor economic efficiency and a low price. Concentrated hydrochloric acid with a concentration of more than 30% has good economic efficiency. Therefore, the dilute hydrochloric acid needs to be concentrated. SUMMARY

[0004] The application provides a hydrochloric acid concentration system for by-product hydrochloric acid in a chlorinated polyethylene production process, which can concentrate dilute hydrochloric acid, improve the economic value of the product, and reduce the production cost.

[0005] The application adopts the following specific technical scheme:

[0006] A hydrochloric acid concentration system for by-product hydrochloric acid in a chlorinated polyethylene production process, comprising a stripping tower and a dilute hydrochloric acid input tank in a condensing section, wherein the dilute hydrochloric acid input tank in the condensing section is connected with an absorption tank and a dilute hydrochloric acid buffer tank, the output end of the dilute hydrochloric acid buffer tank is connected with the liquid input end of the stripping tower, the gas input end of the stripping tower is connected with a reboiler, the gas output end of the stripping tower is connected with the absorption tank, and the output end of the absorption tank is connected with a concentrated hydrochloric acid storage tank.

[0007] The dilute hydrochloric acid input tank in the condensing section is also connected with the input end of the reboiler.

[0008] The stripping tower is provided in multiple groups, and the multiple groups of stripping towers are connected in stages. The tail liquid output end of the stripping tower at the previous stage is connected with the liquid input end of the stripping tower at the next stage, the liquid input end of the stripping tower at the first stage is connected with the output end of the dilute hydrochloric acid buffer tank, and the tail liquid output end of the stripping tower at the last stage is connected with the dilute hydrochloric acid buffer tank through a pipeline or sent to a waste liquid treatment workshop.

[0009] The dilute hydrochloric acid buffer tank is also connected with a condensing section hydrogen chloride gas conveying pipe.

[0010] The gas output end of the stripping tower is also connected with a condenser, and the condensate output end of the condenser is in communication with the dilute hydrochloric acid buffer tank.

[0011] The dilute hydrochloric acid buffer tank is further connected with the liquid input end of the resolving tower through a tail liquid pipeline, and a cleaning mechanism is further arranged on the tail liquid pipeline.

[0012] The output end of the condenser is further connected with a working liquid adjusting tank, and the input end of the working liquid adjusting tank is further connected with a chlorinated working liquid residual liquid pipe.

[0013] The dilute hydrochloric acid buffer tank is further connected with the liquid input end of the resolving tower through a tail liquid pipeline, and a cleaning mechanism is further arranged on the tail liquid pipeline, wherein the cleaning mechanism comprises a cleaning ball arranged in the pipeline.

[0014] The cleaning mechanism further comprises a ball returning pipe, the tail liquid pipeline output end extends into the dilute hydrochloric acid buffer tank, the ball receiving end of the ball returning pipe also communicates with the dilute hydrochloric acid buffer tank, a turning-back pipe is arranged between the tail liquid pipeline and the ball returning pipe, the turning-back pipe is in a semi-circular ring structure, the turning-back pipe comprises a guide pipe part and a liquid outlet pipe part, and a plurality of mesh holes for liquid passing through are arranged on the pipe wall of the liquid outlet pipe part.

[0015] The input end side of the tail liquid pipeline is connected with the tail liquid output end of the resolving tower through a liquid sending pump, the ball launching end of the ball returning pipe communicates with the input end side of the tail liquid pipeline, and the pipeline axis of the ball launching end of the ball returning pipe is arranged towards the tail liquid conveying direction and forms an acute angle with the pipeline axis of the tail liquid pipeline.

[0016] The beneficial effects of the present application are as follows:

[0017] The present application divides the condensed dilute hydrochloric acid generated in the condensing section of the chlorinated polyethylene production process into three parts, one part enters the absorption tank to wait for the addition of hydrogen chloride gas to increase the concentration, another part enters the dilute hydrochloric acid buffer tank, and after the addition of salt, enters the resolving tower to be used as a resolving liquid for resolving hydrogen chloride gas, and the last part enters the reboiler to form high-temperature water vapor and hydrogen chloride gas, which enters the resolving tower to be used as resolving gas, thereby reducing the types of raw materials in the system, reducing the difficulty of material preparation, increasing the concentration of dilute hydrochloric acid by resolving hydrogen chloride, increasing the concentration of hydrochloric acid, and improving the economic value of the product. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The figure is a structural schematic diagram of the present application;

[0019] Figure 2 The figure is a schematic diagram of the cleaning mechanism of the present application;

[0020] In the figure, 1 is a tail liquid pipeline, 2 is a cleaning ball, 3 is a ball returning pipe, 4 is a ball receiving end, 5 is a guide pipe part, 6 is a liquid outlet pipe part, 7 is a liquid sending pump, and 8 is a ball launching end. DETAILED DESCRIPTION

[0021] The application will be further described below in conjunction with the drawings and specific embodiments.

[0022] Specific embodiments such as Figure 1 As shown in the drawings, the application is a chlorinated polyethylene production process by-product hydrochloric acid concentration system, which comprises a stripping tower and a condensing section dilute hydrochloric acid input tank, the condensing section dilute hydrochloric acid input tank is connected with an absorption tank and a dilute hydrochloric acid buffer tank, the output end of the dilute hydrochloric acid buffer tank is connected with the liquid input end of the stripping tower, the gas input end of the stripping tower is connected with a reboiler, the gas output end of the stripping tower is connected with the absorption tank, and the output end of the absorption tank is connected with a concentrated hydrochloric acid storage tank.

[0023] The condensing section dilute hydrochloric acid input tank is also connected with the input end of the reboiler.

[0024] The application separates the condensing dilute hydrochloric acid generated in the condensing section of the chlorinated polyethylene production process into three parts, one part enters the absorption tank to wait for the addition of hydrogen chloride gas to increase the concentration, another part enters the dilute hydrochloric acid buffer tank, and after the addition of salt operation, it enters the stripping tower to be used as a stripping liquid for stripping hydrogen chloride gas, and the last part enters the reboiler to form high-temperature water vapor and hydrogen chloride gas, which enters the stripping tower to be used as a stripping gas, thereby reducing the types of raw materials in the system, reducing the difficulty of material preparation, and increasing the concentration of dilute hydrochloric acid by stripping the hydrogen chloride formed, thereby increasing the concentration of hydrochloric acid and improving the economic value of the product.

[0025] Further, as shown in the drawings, Figure 1 The stripping tower is provided with multiple groups, and the multiple groups of stripping towers are connected in stages, the tail liquid output end of the upper stage stripping tower is connected with the liquid input end of the lower stage stripping tower, the liquid input end of the first stage stripping tower is connected with the output end of the dilute hydrochloric acid buffer tank, and the tail liquid output end of the last stage stripping tower is connected with the dilute hydrochloric acid buffer tank through a pipeline or sent to a waste liquid treatment workshop.

[0026] The stripping tower is provided with multiple stages and connected in stages, so that the same batch of dilute hydrochloric acid is subjected to multiple stripping, and under the action of the stripping gas, the dissolved hydrogen chloride is precipitated as much as possible, thereby improving the precipitation rate and further reducing the concentration of hydrochloric acid in the stripping liquid.

[0027] The tail liquid after stripping is selected according to the concentration in the dilute hydrochloric acid buffer tank, when the concentration is high, the tail liquid can be sent into the dilute hydrochloric acid buffer tank, and when the concentration in the dilute hydrochloric acid buffer tank is low, the tail liquid can be discharged to the waste liquid treatment workshop for neutralization treatment.

[0028] Further, as shown in the drawings, Figure 1As shown, the dilute hydrochloric acid buffer tank is also connected with the condensing section hydrogen chloride gas conveying pipe. By sending the tail liquid into the dilute hydrochloric acid buffer tank, the concentration of hydrochloric acid in the tank is reduced, which helps to absorb more condensed section hydrogen chloride gas, avoids waste, and when too much hydrogen chloride gas cannot be absorbed, the excess hydrogen chloride gas is sent into the condenser, and after condensing, it is added to the hydrogen chloride gas discharged from the stripping column, to increase the concentration of the dilute hydrochloric acid in the absorption tank, and reduce waste.

[0029] Further, as shown in Figure 1 The gas output end of the stripping column is also connected with a condenser, and the condenser condensate output end communicates with the dilute hydrochloric acid buffer tank. The condenser separates the mixed gas of hydrogen chloride and water vapor generated in the stripping column, removes the water, ensures that the hydrogen chloride gas sent into the absorption tank is pure, and facilitates control of the total amount of hydrogen chloride.

[0030] Further, as shown in Figure 1 The dilute hydrochloric acid buffer tank and the liquid input end of the stripping column are also connected with a salt addition tank, and the salt addition tank contains calcium chloride solution. By increasing calcium chloride in the stripping liquid, the content of chloride ions is increased, which helps to resolve hydrogen chloride due to the same ion effect, and calcium chloride is low in cost, which helps to reduce cost.

[0031] Further, as shown in Figure 1 The output end of the condenser is also connected with a working liquid adjusting tank, and the input end of the working liquid adjusting tank is also connected with a chlorinated working liquid residual liquid pipe. The working liquid residual liquid in the working liquid adjusting tank is mixed with the cleaning water after chlorinating polyethylene cleaning, so the concentration is reduced. Therefore, by introducing hydrogen chloride to increase the concentration of hydrochloric acid in the working liquid, and sending it back to the chlorination section to supplement the additives, the working liquid is regenerated, which saves cost.

[0032] Further, as shown in Figure 2 The dilute hydrochloric acid buffer tank and the tail liquid output end of the stripping column are connected by means of a tail liquid pipeline 1, and a cleaning mechanism is also provided on the tail liquid pipeline 1, which includes a cleaning ball 2 arranged in the pipeline.

[0033] Since calcium chloride is used as an additive in the stripping liquid, and due to the continuous heating of the stripping gas in the stripping column, calcium chloride is not easy to precipitate, but after the calcium chloride enters the tail liquid pipeline 1, it is easy to crystallize in the pipeline due to the decrease in temperature, causing blockage. Therefore, by increasing the cleaning ball 2 in the pipeline, the cleaning ball 2 is washed by the cleaning ball 2 in the flow direction of the tail liquid during the flow of the tail liquid, so that the cleaning ball 2 removes the precipitated calcium chloride crystals from the pipe wall, and the calcium chloride crystals are dissolved again in the dilute hydrochloric acid storage tank, reducing the feeding frequency of the salt addition tank, avoiding pipeline blockage, and reducing the amount of raw materials.

[0034] Further, as shown in Figure 2 the tail liquid pipeline 1 output end into the inside of the dilute hydrochloric acid buffer tank, the ball return pipe 3 ball receiving end 4 also communicates with the dilute hydrochloric acid buffer tank, the ball return pipe 3 and the tail liquid pipe between the end of the set back pipe, the back pipe is a semicircular ring structure, the back pipe includes a guide pipe 5 and liquid outlet pipe 6, the liquid outlet pipe 6 on the pipe wall is provided with a mesh for liquid through.

[0035] When the cleaning ball 2 with the tail liquid flow into the back pipe, when the cleaning ball 2 from the tail liquid pipe is pushed into the back pipe, with the water flow continues to blow, so that the cleaning ball 2 from the guide pipe 5 into the liquid outlet pipe 6, finally into the ball return pipe 3 with the liquid outlet pipe 6 communication ball receiving end 4, and the tail liquid from the mesh of the liquid outlet pipe 6 flows into the dilute hydrochloric acid storage tank, a plurality of cleaning ball 2 repeatedly above process, one by one into the ball return pipe 3, by the cleaning ball 2 is pushed through the tail liquid pipe, complete the cleaning of the tail liquid pipe.

[0036] The liquid outlet pipe 6 and the guide pipe 5 corresponding to the arc center angle are 90 DEG, so that the outlet direction of the guide pipe 5 and the ball receiving end of the ball return pipe 3 are at right angles, avoiding the tail liquid due to inertia into the ball return pipe 3, and the ball return pipe 3 diameter is slightly larger than the cleaning ball, so that the cleaning ball exists in the ball return pipe 3 resistance, further avoid the ball return pipe 3 a large number of suction tail liquid, improve the tail liquid discharge efficiency.

[0037] Further, as shown in Figure 2 the input end side of the tail liquid pipeline 1 by means of liquid pump 7 and the tail liquid output end of the analysis tower is connected, the ball return pipe 3 ball sending end 8 and the input end side of the tail liquid pipeline 1 communication, the ball return pipe 3 ball sending end 8 of the pipeline axis towards the tail liquid conveying direction and with the tail liquid pipeline 1 pipeline axis is set at an acute angle.

[0038] By means of the acute angle of the ball return pipe 3 ball sending segment and the tail liquid pipeline 1, the tail liquid flow pumped by the liquid pump 7 can be transported along the tail liquid pipeline 1, and a negative pressure is formed at the ball sending end 8 of the ball return pipe 3, the cleaning ball 2 entering the ball return pipe 3 is sucked to the ball sending end 8, and with the water flow of the tail liquid pipeline 1 enters the next cycle, thereby completing the effect of cleaning the pipe wall calcium chloride precipitation by means of the cleaning ball 2 in the tail liquid conveying process, without setting a special cleaning ball 2 receiver, reducing the cost of equipment, improving economic benefits.

Claims

1. A chlorinated polyethylene production process by-product hydrochloric acid concentration system, comprising a stripping tower and a condenser section dilute hydrochloric acid input tank, characterized in that: The condensation section dilute hydrochloric acid input tank is connected with an absorption groove and a dilute hydrochloric acid buffer tank, the output end of the dilute hydrochloric acid buffer tank is connected with the liquid input end of the resolving tower, the gas input end of the resolving tower is connected with a reboiler, the gas output end of the resolving tower is connected with the absorption groove, and the output end of the absorption groove is connected with a concentrated hydrochloric acid storage tank. The condensation section dilute hydrochloric acid input tank is also connected with the input end of the reboiler. The dilute hydrochloric acid buffer tank and the tail liquid output end of the resolving tower are connected through a tail liquid pipeline (1), and a cleaning mechanism is further arranged on the tail liquid pipeline (1). The cleaning mechanism further comprises a ball returning pipe (3), the output end of the tail liquid pipeline (1) extends into the dilute hydrochloric acid buffer tank, the ball collecting end (4) of the ball returning pipe (3) also communicates with the dilute hydrochloric acid buffer tank, a turning-back pipe is arranged between the ball returning pipe (3) and the end of the tail liquid pipeline, the turning-back pipe has a semicircular ring structure, and the turning-back pipe comprises a guide pipe portion (5) and a liquid outlet pipe portion (6), and the pipe wall of the liquid outlet pipe portion (6) is provided with mesh holes for liquid passing. The input end side of the tail liquid pipeline (1) is connected with the tail liquid output end of the resolving tower through a liquid sending pump (7), the ball emitting end (8) of the ball returning pipe (3) communicates with the input end side of the tail liquid pipeline (1), and the pipe axis of the ball emitting end (8) of the ball returning pipe (3) is arranged towards the tail liquid conveying direction and forms an acute angle with the pipe axis of the tail liquid pipeline (1).

2. The system for increasing the concentration of hydrochloric acid produced as a byproduct of a chlorinated polyethylene production process according to claim 1, characterized in that: The resolving tower is provided with multiple groups, and the multiple groups of resolving towers are connected in stages, the tail liquid output end of the upper-stage resolving tower is connected with the liquid input end of the lower-stage resolving tower, the liquid input end of the first-stage resolving tower is connected with the output end of the dilute hydrochloric acid buffer tank, and the tail liquid output end of the last-stage resolving tower is connected with the dilute hydrochloric acid buffer tank through a pipeline or sent to a waste liquid treatment workshop.

3. The system according to claim 1, wherein the system is characterized by: The dilute hydrochloric acid buffer tank is also connected with a condensation section hydrogen chloride gas conveying pipe.

4. The system according to claim 1, wherein the system is characterized by: The gas output end of the resolving tower is also connected with a condenser, and the condensate output end of the condenser communicates with the dilute hydrochloric acid buffer tank.

5. The system for increasing the concentration of hydrochloric acid produced as a byproduct of a chlorinated polyethylene production process according to claim 1, characterized in that: The dilute hydrochloric acid buffer tank and the liquid input end of the resolving tower are also connected with a salt adding tank, and the salt adding tank contains calcium chloride solution.

6. The system according to claim 4, wherein the system is characterized by: The output end of the condenser is also connected with a working liquid adjusting tank, and the input end of the working liquid adjusting tank is also connected with a chlorinated working liquid residual liquid pipe.

Images