CN-224194124-U - Caustic soda evaporation concentration system

Abstract

The utility model relates to the technical field of chlor-alkali chemical industry, and particularly discloses a caustic soda evaporation concentration system which comprises a first-effect falling film evaporator, a second-effect falling film evaporator and a third-effect falling film evaporator, wherein the first-effect falling film evaporator, the second-effect falling film evaporator and the third-effect falling film evaporator are sequentially connected, a first flash tank is arranged at a condensate outlet of the third-effect falling film evaporator heat exchanger, a second flash tank is arranged between a condensate outlet of the second-effect falling film evaporator heat exchanger and a heat exchanger inlet of the first-effect falling film evaporator, the second-effect falling film evaporator and the third-effect falling film evaporator are combined, secondary steam generated in a previous stage is used as a heating source of the next effect, the utilization rate of steam is improved, a flash tank is added at a condensate outlet of the second-effect falling film evaporator, condensate generated in a second-effect secondary steam negative pressure state is utilized for heat exchange of three-effect alkali liquor, and latent heat of the condensate is fully utilized.

Inventors

• YIN QUAN
• YUAN FEI
• WANG LE
• LIU ZHUGUO
• WANG RUI
• CHENG XU
• LI HAIJUN
• CUI YONGQIANG
• HU XUEDONG
• YING QIANG
• LIU YANQING
• LIANG DAFENG

Assignees

• 中盐吉兰泰氯碱化工有限公司
• 中盐内蒙古化工股份有限公司

Dates

Publication Date

20260505

Application Date

20250527

Claims (6)

1. 1. A caustic soda evaporation concentration system is characterized by comprising a first-effect falling film evaporator (1), a second-effect falling film evaporator (2) and a third-effect falling film evaporator (3), wherein a liquid outlet of the first-effect falling film evaporator (1) is connected with a liquid inlet of the second-effect falling film evaporator (2) through a first-effect alkaline liquid pump (6), a liquid outlet of the second-effect falling film evaporator (2) is connected with a liquid inlet of the third-effect falling film evaporator (3) through a second-effect alkaline liquid pump (7), a liquid outlet of the third-effect falling film evaporator (3) is connected with an inlet of the third-effect alkaline liquid pump (8), a condensate outlet of a heat exchanger of the third-effect falling film evaporator (3) is connected with an inlet of a first flash evaporator (4), a secondary steam outlet of the third-effect falling film evaporator (3) is connected with an inlet of the heat exchanger of the second-effect falling film evaporator (2), a condensate outlet of the second-effect falling film evaporator (2) is connected with an inlet of the second flash evaporator (5), a steam inlet of the second flash evaporator (5) is connected with a condensate outlet of the second flash evaporator (9 of the second-effect falling film evaporator (1), a condensate outlet of the third-effect falling film evaporator (3) is connected with a condensate outlet of the second flash evaporator (9), the secondary steam outlet of the first-effect falling film evaporator (1) is connected with the inlet of an air condenser (10), the emptying port of the air condenser (10) is connected with the inlet of a vacuum pump (11), and the condensate port of the air condenser (10) is connected with the inlet of a condensate recovery tank (9).
2. 2. The caustic soda evaporation and concentration system according to claim 1, further comprising a double-effect alkali liquor heat exchanger (12) and a double-effect steam heat exchanger (13), wherein an outlet of the triple-effect alkali liquor pump (8) is connected with a heat source inlet of the double-effect alkali liquor heat exchanger (12), a condensate outlet of the first flash tank (4) is connected with a heat source inlet of the double-effect steam heat exchanger (13), an outlet of the double-effect alkali liquor pump (7) is respectively connected with a medium inlet of the double-effect alkali liquor heat exchanger (12) and a medium inlet of the double-effect steam heat exchanger (13), and a medium outlet of the double-effect alkali liquor heat exchanger (12) and a medium outlet of the double-effect steam heat exchanger (13) are respectively connected with a liquid inlet of the triple-effect falling film evaporator (3).
3. 3. The caustic soda evaporation and concentration system according to claim 2, further comprising an effective lye heat exchanger (14) and an effective steam heat exchanger (15), wherein a heat source outlet of the second effective lye heat exchanger (12) is connected with a heat source inlet of the first effective lye heat exchanger (14), a heat source outlet of the second effective steam heat exchanger (13) is connected with a heat source inlet of the first effective steam heat exchanger (15), an outlet of the first effective lye pump (6) is respectively connected with a medium inlet of the first effective lye heat exchanger (14) and a medium inlet of the first effective steam heat exchanger (15), and a medium outlet of the first effective lye heat exchanger (14) and a medium outlet of the first effective steam heat exchanger (15) are respectively connected with a liquid inlet of the second effective falling film evaporator (2).
4. 4. A caustic soda evaporation and concentration system according to claim 3, further comprising a triple effect lye heat exchanger (16), wherein the condensate outlet of the first flash tank (4) is connected with the heat source inlet of the triple effect lye heat exchanger (16), the heat source outlet of the triple effect lye heat exchanger (16) is connected with the heat source inlet of the double effect lye heat exchanger (12), the medium outlet of the double effect lye heat exchanger (12) is connected with the medium inlet of the triple effect lye heat exchanger (16), and the medium outlet of the triple effect lye heat exchanger (16) is connected with the liquid inlet of the triple effect falling film evaporator (3).
5. 5. A caustic soda evaporation and concentration system according to claim 1, characterized in that the condensate recovery tank (9) outlet is connected to the condensate recovery pump (17) inlet.
6. 6. The caustic soda evaporation and concentration system according to claim 4, further comprising a finished product cooler (18), wherein the heat source outlet of the lye heat exchanger (14) is connected to the heat source inlet of the finished product cooler (18).

Description

Caustic soda evaporation concentration system Technical field: The utility model relates to the technical field of chlor-alkali chemical industry, in particular to a caustic soda evaporation and concentration system. The background technology is as follows: caustic soda (sodium hydroxide) is an important product in the chlor-alkali industry, and is prepared by using an electrolysis sodium chloride mode in the chlor-alkali industry, wherein the concentration of liquid alkali generated by an electrolysis process is about 30%, the concentration of the liquid alkali needs to be further concentrated to 50%, the storage tank space required by the storage of the liquid alkali can be greatly reduced by improving the concentration of the liquid alkali, the storage and transportation cost is saved, and other byproducts with higher concentration are required to be related, so that 30% of the liquid alkali generated by the electrolysis process needs to be concentrated. In the existing caustic soda evaporation and concentration equipment, multiple-effect falling film evaporation is used, steam is used as a heat source to enable moisture in liquid caustic soda to evaporate to achieve a concentration effect, the temperature required by the falling film evaporator is required to be increased in order to ensure the evaporation efficiency of a tube array, the temperature of exhaust gas is higher, latent heat of the steam in the exhaust gas is not effectively released, the utilization efficiency of the steam is reduced, and therefore a large amount of heat sources are required to be consumed by concentrated caustic soda, and the energy consumption is higher. The utility model comprises the following steps: the utility model aims to provide a caustic soda evaporation concentration system which aims to solve the problems in the prior art. The caustic soda evaporation concentration system comprises a first-effect falling film evaporator, a second-effect falling film evaporator and a third-effect falling film evaporator, wherein a liquid outlet of the first-effect falling film evaporator is connected with a liquid inlet of the second-effect falling film evaporator through a first-effect alkaline pump, a liquid outlet of the second-effect falling film evaporator is connected with a liquid inlet of the third-effect falling film evaporator through a second-effect alkaline pump, a liquid outlet of the third-effect falling film evaporator is connected with an inlet of the third-effect alkaline pump, a condensate outlet of the third-effect falling film evaporator is connected with an inlet of a first flash tank, a condensate outlet of the third-effect falling film evaporator is connected with an inlet of the second-effect falling film evaporator, a condensate outlet of the second-effect falling film evaporator is connected with an inlet of the second flash tank, a steam recovery port of the second flash tank is connected with an inlet of the first-effect falling film evaporator, a condensate outlet of the second-effect falling film evaporator is connected with a condensate inlet of the second flash tank, and a condensate inlet of the condensate pump is connected with a condensate inlet of the condensate pump. Further, the device also comprises a double-effect alkali liquor heat exchanger and a double-effect steam heat exchanger, wherein the outlet of the triple-effect alkali liquor pump is connected with the heat source inlet of the double-effect alkali liquor heat exchanger, the condensate outlet of the first flash tank is connected with the heat source inlet of the double-effect steam heat exchanger, the outlet of the double-effect alkali liquor pump is respectively connected with the medium inlet of the double-effect alkali liquor heat exchanger and the medium inlet of the double-effect steam heat exchanger, and the medium outlet of the double-effect alkali liquor heat exchanger and the medium outlet of the double-effect steam heat exchanger are respectively connected with the liquid inlet of the triple-effect falling film evaporator. Further, the device also comprises an effective alkali liquor heat exchanger and an effective steam heat exchanger, wherein the heat source outlet of the two-effect alkali liquor heat exchanger is connected with the heat source inlet of the one-effect alkali liquor heat exchanger, the heat source outlet of the two-effect steam heat exchanger is connected with the heat source inlet of the one-effect steam heat exchanger, the outlet of the one-effect alkali liquor pump is respectively connected with the medium inlet of the one-effect alkali liquor heat exchanger and the medium inlet of the one-effect steam heat exchanger, and the medium outlet of the one-effect alkali liquor heat exchanger and the medium outlet of the one-effect steam heat exchanger are respectively connected with the liquid inlet of the two-effect falling film evaporator. Further, the device also comprises a three-effect alkali liquor h