Negative pressure flash evaporation device for solid caustic soda process

Abstract

The utility model relates to the technical field of solid caustic soda processes, in particular to a solid caustic soda process negative pressure flash evaporation device which comprises a preconcentrator, a final concentrator, a flash evaporation tank, a distribution tank, a surface condenser and a condensate tank. And a second alkali liquor conveying pipeline is fixedly communicated between the bottom outlet of the preconcentrator and the top inlet of the final concentrator. The device is reasonable and compact in structure and convenient to use, alkali steam in the pre-concentrator and the final concentrator is pumped into the surface condenser, so that negative pressure is formed in the pre-concentrator and the final concentrator, meanwhile, alkali steam in the flash tank is pumped into the surface condenser through the additionally arranged negative pressure pipeline, and the alkali steam in the flash tank is pumped into the surface condenser through the additionally arranged negative pressure pipeline. And after the negative pressure is formed in the preconcentrator and the flash tank, the boiling point of the alkali liquor is reduced, so that the consumption of natural gas during concentration of the alkali liquor is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of solid alkali process and is a negative pressure flash evaporation device for solid alkali process. Background Art

[0002] At present, the annual design production capacity of the ion membrane caustic soda evaporation and concentration device in the caustic soda workshop of the chemical enterprise is increasing day by day. The Swiss Bot three-effect countercurrent evaporation process has been introduced, which mainly evaporates the 32% alkali liquid produced by the ion membrane device to 48% for use in the concentration device; the single-line production capacity of 8 sets of concentration devices is 75,000 tons / year, and the advanced molten salt method continuous alkali production process is adopted, which mainly concentrates the 48% alkali liquid sent from the evaporation device to 62% alkali liquid in the pre-concentrator. The 62% alkali liquid is concentrated to 98.3% alkali liquid in the final concentrator, and the alkali liquid is finally concentrated to 98.5% alkali liquid after the flash tank. This link is an important control point affecting the use of natural gas. Then, the 98.5% alkali liquid is packaged through tableting to become the final product.

[0003] In the existing solid alkali process, 98% of the alkali solution is sent from the final concentrator to the flash tank for flash evaporation, and the concentration is increased from 98.3% to 98.5%. However, the pressure in the tank is standard atmospheric pressure, the alkali temperature is about 390℃, and about 104m3 of natural gas is consumed. 3 / t, resulting in high natural gas consumption, long production time and low efficiency. Summary of the invention

[0004] The utility model provides a negative pressure flash evaporation device for solid alkali process, which overcomes the deficiencies of the prior art and can effectively solve the problems of high natural gas consumption, long production time and low efficiency in the existing solid alkali process.

[0005] The technical scheme of the utility model is achieved through the following measures: a negative pressure flash device for solid alkali process, comprising a pre-concentrator, a final concentrator, a flash tank, a distribution tank, a surface condenser and a condensate tank, wherein a first alkali liquid conveying pipeline is fixedly connected to a top inlet of the pre-concentrator, a second alkali liquid conveying pipeline is fixedly connected between a bottom outlet of the pre-concentrator and a top inlet of the final concentrator, a third alkali liquid conveying pipeline is fixedly connected between a bottom outlet of the final concentrator and a bottom inlet of the flash tank, a fourth alkali liquid conveying pipeline is fixedly connected between a bottom outlet of the flash tank and an inlet of the distribution tank, a venting pipeline is fixedly connected to a top outlet of the flash tank, a first alkali steam conveying pipeline is fixedly connected between an upper outlet of the final concentrator and an upper inlet of the pre-concentrator, a second alkali steam conveying pipeline is fixedly connected between a lower outlet of the pre-concentrator and an inlet of the surface condenser, a steam condensate inlet pipeline is fixedly connected between the surface condenser outlet and the inlet of the condensate tank, and a negative pressure pipeline is fixedly connected between the second alkali steam conveying pipeline and the venting pipeline.

[0006] The following are further optimizations and / or improvements to the above utility model technical solution:

[0007] The fourth alkali solution delivery pipeline extends to the inner side of the middle part of the distribution tank, and the fourth alkali solution delivery pipeline is in a bow shape.

[0008] A wire mesh demister is fixedly installed on the venting pipeline between the negative pressure pipeline and the flash tank, and a wire mesh demister is fixedly installed on the second alkali steam delivery pipeline between the negative pressure pipeline and the pre-concentrator.

[0009] A pneumatic valve is fixedly installed on the negative pressure pipeline, and a remote pressure gauge is arranged between the vent pipeline and the pneumatic valve.

[0010] An alkali solution delivery pump is fixedly installed on the above-mentioned second alkali solution delivery pipeline, and an alkali steam delivery pump is fixedly installed on the second alkali steam delivery pipeline between the surface condenser and the wire mesh demister.

[0011] A drainage pipeline is fixedly installed on the third alkali solution delivery pipeline.

[0012] The utility model has a reasonable and compact structure and is easy to use. The alkali vapor in the pre-concentrator and the final concentrator is extracted into the surface condenser, thereby forming a negative pressure in the pre-concentrator and the final concentrator. At the same time, the alkali vapor in the flash tank is extracted into the surface condenser through an additional negative pressure pipeline, thereby forming a negative pressure in the flash tank. After the negative pressure is formed in the pre-concentrator and the flash tank, the boiling point of the alkali solution is reduced, thereby reducing the consumption of natural gas when the alkali solution is concentrated, and effectively solving the problems of high natural gas consumption, long production time and low efficiency in the existing solid alkali process. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Attached Figure 1 The figure is a schematic diagram of the process flow of the best embodiment of the utility model.

[0014] The codes in the attached drawings are: 1 is a pre-concentrator, 2 is a final concentrator, 3 is a flash tank, 4 is a distribution tank, 5 is a surface condenser, 6 is a condensate tank, 7 is a first alkali liquid delivery pipeline, 8 is a second alkali liquid delivery pipeline, 9 is a third alkali liquid delivery pipeline, 10 is a fourth alkali liquid delivery pipeline, 11 is a venting pipeline, 12 is a first alkali steam delivery pipeline, 13 is a second alkali steam delivery pipeline, 14 is a steam condensate inlet pipeline, 15 is a negative pressure pipeline, 16 is a wire mesh demister, 17 is a pneumatic valve, 18 is a remote pressure gauge, 19 is an alkali liquid delivery pump, 20 is an alkali steam delivery pump, and 21 is a discharge pipeline. DETAILED DESCRIPTION

[0015] The present invention is not limited by the following embodiments, and specific implementation methods can be determined according to the technical solution of the present invention and actual conditions.

[0016] In the present invention, for the convenience of description, the relative position relationship of each component is described according to the attached manual. Figure 1 The layout is described in detail, such as the positional relationship of front, back, top, bottom, left, right, etc., which is based on the attached manual. Figure 1 The layout direction is determined by the

[0017] The present invention is further described below in conjunction with the embodiments and drawings:

[0018] As attached Figure 1 As shown, the negative pressure flash evaporation device of the solid alkali process includes a pre-concentrator 1, a final concentrator 2, a flash tank 3, a distribution tank 4, a surface condenser 5 and a condensate tank 6. The top inlet of the pre-concentrator 1 is fixedly connected with a first alkali liquid delivery pipeline 7, the bottom outlet of the pre-concentrator 1 and the top inlet of the final concentrator 2 are fixedly connected with a second alkali liquid delivery pipeline 8, the bottom outlet of the final concentrator 2 and the bottom inlet of the flash tank 3 are fixedly connected with a third alkali liquid delivery pipeline 9, and the bottom outlet of the flash tank 3 and the inlet of the distribution tank 4 are fixedly connected with a alkali liquid delivery pipeline 10. A fourth liquid delivery pipeline 10 is fixedly connected to the top outlet of the flash tank 3 with a venting pipeline 11, a first alkali steam delivery pipeline 12 is fixedly connected between the upper outlet of the final concentrator 2 and the upper inlet of the pre-concentrator 1, a second alkali steam delivery pipeline 13 is fixedly connected between the lower outlet of the pre-concentrator 1 and the inlet of the surface condenser 5, a steam condensate inlet pipeline 14 is fixedly connected between the outlet of the surface condenser 5 and the inlet of the condensate tank 6, and a negative pressure pipeline 15 is fixedly connected between the second alkali steam delivery pipeline 13 and the venting pipeline 11.

[0019] The utility model extracts the alkali vapor in the pre-concentrator 1 and the final concentrator 2 into the surface condenser 5, thereby forming a negative pressure in the pre-concentrator 1 and the final concentrator 2. At the same time, the alkali vapor in the flash tank 3 is extracted into the surface condenser 5 through the additional negative pressure pipeline 15, so that a negative pressure is also formed in the flash tank 3. The negative pressure in the pre-concentrator 1, the final concentrator 2 and the flash tank 3 is controlled between -10KPa and -30KPa. After the negative pressure is formed in the pre-concentrator 1 and the flash tank 3, the boiling point of the alkali solution is further reduced, thereby reducing the consumption of natural gas during the concentration of the alkali solution. In actual operation, the use of this device in the solid alkali process can reduce the unit consumption of natural gas by 1.9m 3 / t, which can save about 1.873 million yuan in costs each year, shorten production time and improve efficiency.

[0020] According to actual needs, the above-mentioned solid alkali process negative pressure flash device can be further optimized and / or improved:

[0021] As attached Figure 1As shown, the fourth alkali liquid delivery pipeline 10 extends to the inner side of the middle of the distribution tank 4, and the fourth alkali liquid delivery pipeline 10 is in an arc shape. During use, when the alkali liquid is delivered to the inner side of the middle of the distribution tank 4, a liquid seal is formed, so that when the alkali vapor is extracted, a continuous and stable negative pressure can be formed in the flash tank 3; the fourth alkali liquid delivery pipeline 10 in an arc shape can stably control the flow rate of the alkali liquid.

[0022] As attached Figure 1 As shown, a wire mesh demister 16 is fixedly installed on the vent line 11 between the negative pressure line 15 and the flash tank 3, and a wire mesh demister 16 is fixedly installed on the second alkali steam delivery line 13 between the negative pressure line 15 and the pre-concentrator 1. During use, the alkali steam in the pre-concentrator 1 and the final concentrator 2 is captured by the wire mesh demister 16 on 13, and the alkali steam in the flash tank 3 is captured by the wire mesh demister 16 on the vent line 11, which does not affect the normal use of subsequent condensed water.

[0023] As attached Figure 1 As shown, a pneumatic valve 17 is fixedly installed on the negative pressure pipeline 15, and a remote pressure gauge 18 is arranged between the venting pipeline 11 and the pneumatic valve 17. Through such an arrangement, the pressure during flash evaporation in the flash tank 3 can be observed in time.

[0024] As attached Figure 1 As shown, an alkali solution delivery pump 19 is fixedly installed on the second alkali solution delivery pipeline 8 , and an alkali steam delivery pump 20 is fixedly installed on the second alkali steam delivery pipeline 13 between the surface condenser 5 and the wire mesh demister 16 .

[0025] As needed, such as attached Figure 1 As shown, a drainage pipeline 21 is fixedly installed on the third alkali solution delivery pipeline 9. During use, when the device is shut down, the alkali solution is discharged through the drainage pipeline 21.

[0026] As needed, such as attached Figure 1 As shown, the bottom of the third alkali solution delivery pipeline 9 is U-shaped. During use, the U-shaped third alkali solution delivery pipeline 9 can stably control the flow rate of the alkali solution.

[0027] The above technical features constitute the best implementation example of the present utility model, which has strong adaptability and best implementation effect. Non-essential technical features can be added or removed according to actual needs to meet the needs of different situations.

[0028] The use process of the best embodiment of the utility model is as follows: first, alkali liquid with a concentration of 48% is sent to the pre-concentrator 1 through the first alkali liquid delivery pipeline 7 for concentration to obtain alkali liquid with a concentration of 62%, and the alkali liquid with a concentration of 62% is sent to the final concentrator 2 through the alkali liquid delivery pump 19 through the second alkali liquid delivery pipeline 8 for concentration to obtain alkali liquid with a concentration of 96%, and the alkali liquid with a concentration of 96% is sent to the flash tank 3 through the third alkali liquid delivery pipeline 9 for flash evaporation to obtain alkali liquid with a concentration of 98.5%, and the alkali liquid with a concentration of 98.5% is sent to the distribution tank 4 through the fourth alkali liquid delivery pipeline 10 for liquid sealing, and is to be carried out for subsequent film making;

[0029] Alkali steam is generated during the concentration in the pre-concentrator 1, the final concentrator 2 and the flash tank 3. The alkali steam in the final concentrator 2 is delivered to the pre-concentrator 1 through the first alkali steam delivery pipeline 12 by the alkali steam delivery pump 20, and then delivered to the surface condenser 5 through the second alkali steam delivery pipeline 13. Then, the alkali steam in the flash tank 3 is delivered to the surface condenser 5 through the venting pipeline 11, the negative pressure pipeline 15 and the second alkali steam delivery pipeline 13 for condensation, and the condensed steam is delivered to the condensate tank 6 for temporary storage. At this time, the pressure in the pre-concentrator 1, the final concentrator 2 and the flash tank 3 is negative pressure, which reduces the consumption of natural gas during the concentration of alkali liquid.

Claims

1. A negative pressure flash evaporation device for solid alkali process, characterized in that The invention comprises a pre-concentrator, a final concentrator, a flash tank, a distribution tank, a surface condenser and a condensate tank, wherein the top inlet of the pre-concentrator is fixedly connected with a first alkali liquid delivery pipeline, the bottom outlet of the pre-concentrator and the top inlet of the final concentrator are fixedly connected with a second alkali liquid delivery pipeline, the bottom outlet of the final concentrator and the bottom inlet of the flash tank are fixedly connected with a third alkali liquid delivery pipeline, the bottom outlet of the flash tank and the inlet of the distribution tank are fixedly connected with a fourth alkali liquid delivery pipeline, the top outlet of the flash tank is fixedly connected with a venting pipeline, the upper outlet of the final concentrator and the upper inlet of the pre-concentrator are fixedly connected with a first alkali steam delivery pipeline, the lower outlet of the pre-concentrator and the inlet of the surface condenser are fixedly connected with a second alkali steam delivery pipeline, the surface condenser outlet and the inlet of the condensate tank are fixedly connected with a steam condensate inlet pipeline, and the second alkali steam delivery pipeline and the venting pipeline are fixedly connected with a negative pressure pipeline.

2. The solid alkali process negative pressure flash evaporation device according to claim 1, characterized in that The fourth alkali solution delivery pipeline extends to the inner side of the middle part of the distribution tank, and the fourth alkali solution delivery pipeline is in a bow shape.

3. The solid alkali process negative pressure flash evaporation device according to claim 1 or 2, characterized in that A wire mesh demister is fixedly installed on the venting pipeline between the negative pressure pipeline and the flash tank, and a wire mesh demister is fixedly installed on the second alkali steam delivery pipeline between the negative pressure pipeline and the pre-concentrator.

4. The solid alkali process negative pressure flash evaporation device according to claim 1 or 2, characterized in that A pneumatic valve is fixedly installed on the negative pressure pipeline, and a remote pressure gauge is arranged between the vent pipeline and the pneumatic valve.

5. The solid alkali process negative pressure flash evaporation device according to claim 3, characterized in that A pneumatic valve is fixedly installed on the negative pressure pipeline, and a remote pressure gauge is arranged between the vent pipeline and the pneumatic valve.

6. The solid alkali process negative pressure flash evaporation device according to claim 5, characterized in that A alkali solution delivery pump is fixedly installed on the second alkali solution delivery pipeline, and a alkali steam delivery pump is fixedly installed on the second alkali steam delivery pipeline between the surface condenser and the wire mesh demister.

7. The solid alkali process negative pressure flash evaporation device according to claim 3, characterized in that A alkali solution delivery pump is fixedly installed on the second alkali solution delivery pipeline, and a alkali steam delivery pump is fixedly installed on the second alkali steam delivery pipeline between the surface condenser and the wire mesh demister.

8. The negative pressure flash evaporation device for solid alkali process according to claim 4, characterized in that A alkali solution delivery pump is fixedly installed on the second alkali solution delivery pipeline, and a alkali steam delivery pump is fixedly installed on the second alkali steam delivery pipeline between the surface condenser and the wire mesh demister.

9. The solid alkali process negative pressure flash device according to claim 1 or 2 or 5 or 7 or 8, characterized in that A drainage pipeline is fixedly installed on the third alkali solution delivery pipeline.

10. The negative pressure flash evaporation device for solid alkali process according to claim 6, characterized in that A drainage pipeline is fixedly installed on the third alkali solution delivery pipeline.

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