阅读说明：本技术 一种液碱浓缩装置及浓缩方法 (Liquid caustic soda concentration device and concentration method ) 是由 周道选 张文凯 于 2020-11-27 设计创作，主要内容包括：本发明公开了一种液碱浓缩装置及浓缩方法,包括喷淋塔、液碱循环系统和氮气循环系统,喷淋塔上设置有补液口、补气口,排液口和排污口,液碱循环系统和氮气循环系统分别与喷淋塔相连通；液碱循环系统包括循环泵和换热器一,循环泵、换热器一和喷淋塔之间依次通过管路连通形成回路；氮气循环系统包括风机、蒸发器、换热器二和冷凝器,风机、蒸发器、换热器二、冷凝器和喷淋塔之间依次通过管路连通形成回路；换热器与水源热泵之间设置有热水泵,换热器与水源热泵之间通过管路连通形成回路,水源热泵和换热器二之间设置有冷水泵,水源热泵、冷水泵和换热器二之间通过管路连通形成回路。该装置可有效解决现有的液碱浓缩过程中存在的汽耗过大的问题。(The invention discloses a liquid caustic soda concentration device and a concentration method, which comprise a spray tower, a liquid caustic soda circulation system and a nitrogen circulation system, wherein the spray tower is provided with a liquid supplementing port, a gas supplementing port, a liquid discharging port and a sewage discharging port, and the liquid caustic soda circulation system and the nitrogen circulation system are respectively communicated with the spray tower; the liquid caustic soda circulating system comprises a circulating pump and a first heat exchanger, and the circulating pump, the first heat exchanger and the spray tower are sequentially communicated through pipelines to form a loop; the nitrogen circulating system comprises a fan, an evaporator, a second heat exchanger and a condenser, and the fan, the evaporator, the second heat exchanger, the condenser and the spray tower are sequentially communicated through pipelines to form a loop; a hot water pump is arranged between the heat exchanger and the water source heat pump, the heat exchanger and the water source heat pump are communicated through a pipeline to form a loop, a cold water pump is arranged between the water source heat pump and the second heat exchanger, and the water source heat pump, the cold water pump and the second heat exchanger are communicated through pipelines to form a loop. The device can effectively solve the problem of excessive steam consumption in the existing liquid caustic soda concentration process.)

1. The liquid caustic soda concentration device is characterized by comprising a spray tower (1), a liquid caustic soda circulation system and a nitrogen circulation system, wherein a liquid supplementing port (2), a gas supplementing port (3), a liquid discharging port (4) and a sewage discharging port (5) are formed in the spray tower (1), and the liquid caustic soda circulation system and the nitrogen circulation system are respectively communicated with the spray tower (1);

the liquid caustic soda circulating system comprises a circulating pump (6) and a first heat exchanger (7), and the circulating pump (6), the first heat exchanger (7) and the spray tower (1) are communicated with one another through pipelines in sequence to form a loop; the nitrogen circulating system comprises a fan (8), an evaporator (9), a second heat exchanger (10) and a condenser (11), wherein the fan (8), the evaporator (9), the second heat exchanger (10), the condenser (11) and the spray tower (1) are communicated in sequence through pipelines to form a loop;

the water source heat pump system is characterized by further comprising a water source heat pump (12), a hot water pump (13) is arranged between the first heat exchanger (7) and the water source heat pump (12), the first heat exchanger (7) and the water source heat pump (12) are communicated through a pipeline to form a loop, a cold water pump (14) is arranged between the water source heat pump (12) and the second heat exchanger (10), and the water source heat pump (12), the cold water pump (14) and the second heat exchanger (10) are communicated through pipelines to form a loop.

2. The caustic soda liquid concentrating device according to claim 1, wherein a caustic soda liquid circulating outlet (15), a caustic soda liquid circulating inlet (16), a nitrogen gas circulating outlet (17) and a nitrogen gas circulating inlet (18) are further arranged on the spray tower (1), the nitrogen gas circulating outlet (17) is arranged at the top of the spray tower (1), and the nitrogen gas circulating inlet (18) is arranged at the middle lower part of the spray tower (1).

3. The caustic soda liquid concentrating device according to claim 1, wherein the bottom of the spray tower (1) is arranged in an inverted cone shape, and the drain outlet (5) is arranged at the bottom of the inverted cone shape.

4. The caustic soda liquid concentration device according to claim 1, wherein the second heat exchanger (10) comprises a first-effect heat exchanger (19), a second-effect heat exchanger (20) and a third-effect heat exchanger (21) which are communicated in sequence.

5. The caustic soda liquid concentrator according to claim 1, characterized in that a packing layer (22) is arranged in the spray tower (1).

6. The caustic soda liquid concentrating device according to claim 5, characterized in that a spray head (23) is arranged in the spray tower (1), the spray head (23) is communicated with the caustic soda liquid circulation inlet (16) through a water distribution pipeline, and the spray head (23) is arranged at the upper part of the packing layer (22).

7. A liquid caustic soda concentration method using the liquid caustic soda concentration apparatus as claimed in any one of claims 1 to 6, comprising the steps of:

(1) nitrogen is filled into the spray tower (1) through a nitrogen inlet, and liquid caustic soda is supplemented into the spray tower (1) through a liquid supplementing port (2);

(2) pumping the liquid caustic soda in the spray tower (1) into a heat exchanger I (7) by using a circulating pump (6), heating the liquid caustic soda, pumping the heated liquid caustic soda back to the spray tower (1) and spraying the heated liquid caustic soda through a spray head (23);

(3) the wet and hot nitrogen in the spray tower (1) is pumped into an evaporator (9), a first-effect heat exchanger (19), a second-effect heat exchanger (20), a third-effect heat exchanger (21) and a condenser (11) in sequence by a fan (8) and then is conveyed back into the spray tower (1);

(4) pumping the water body in the first heat exchanger (7) into a water source heat pump (12) by using a hot water pump (13) and then pumping the water body back to the first heat exchanger (7);

(5) a water body in the water source heat pump (12) is pumped into the primary heat exchanger (19), the secondary heat exchanger (20) and the tertiary heat exchanger (21) in sequence by using a cold water pump (14) and then is pumped back into the water source heat pump (12);

(6) the steps are carried out simultaneously, the circulation is repeated, and when the mass concentration of the liquid caustic soda meets the requirement, the liquid caustic soda is discharged through the liquid discharge port (4).

8. The method for concentrating liquid caustic soda as claimed in claim 7, wherein the mass concentration of the liquid caustic soda in the step (2) is 28-32%.

9. The method for concentrating liquid caustic soda as claimed in claim 7, wherein the mass concentration of the discharged liquid caustic soda in the step (6) is 37 to 39%.

Technical Field

The invention belongs to the technical field of liquid caustic soda concentration, and particularly relates to a liquid caustic soda concentration device and a concentration method.

Background

In the chlor-alkali industry, the electrolytic alkali liquor evaporation adopts steam multi-effect concentration evaporation to concentrate the liquid alkali with the concentration of 30% to the concentration of 50% and solid alkali, the main purpose is to improve the alkali liquor concentration, and the gas consumption is one of two large energy consumptions of chlor-alkali enterprises, and is second to the electricity consumption. The energy consumption area of the production process of the caustic soda by the electrolytic method comprises the working procedures of rectification, brine, electrolysis, chlorine-hydrogen treatment, liquid caustic soda evaporation, solid caustic soda and the like, and the energy consumption distribution is as follows: 2.0% of rectification, 53.2% of electrolysis, 3.9% of brine, 1.2% of chlorine-hydrogen treatment, 14.6% of solid caustic soda and 25.1% of liquid caustic soda evaporation, wherein the liquid caustic soda evaporation is a main energy consumption process which is only second to the electrolysis, and the energy consumption mainly comprises steam consumption and is about more than 74%. Therefore, the research on energy conservation in the liquid caustic soda evaporation and concentration process is of great significance.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a liquid caustic soda concentration device and a concentration method, and the device can effectively solve the problem of excessive steam consumption in the existing liquid caustic soda concentration process.

In order to achieve the purpose, the technical scheme adopted by the invention for solving the technical problems is as follows:

a liquid caustic soda concentration device comprises a spray tower, a liquid caustic soda circulation system and a nitrogen circulation system, wherein a liquid supplementing port, a gas supplementing port, a liquid discharging port and a sewage discharging port are arranged on the spray tower, and the liquid caustic soda circulation system and the nitrogen circulation system are respectively communicated with the spray tower;

the liquid caustic soda circulating system comprises a circulating pump and a first heat exchanger, and the circulating pump, the first heat exchanger and the spray tower are sequentially communicated through pipelines to form a loop; the nitrogen circulating system comprises a fan, an evaporator, a second heat exchanger and a condenser, and the fan, the evaporator, the second heat exchanger, the condenser and the spray tower are sequentially communicated through pipelines to form a loop;

a hot water pump is arranged between the heat exchanger and the water source heat pump, the heat exchanger and the water source heat pump are communicated through a pipeline to form a loop, a cold water pump is arranged between the water source heat pump and the second heat exchanger, and the water source heat pump, the cold water pump and the second heat exchanger are communicated through pipelines to form a loop.

In the scheme, the upper part of the spray tower is cylindrical, the lower part of the spray tower is in an inverted cone shape, the interior of the spray tower is sealed, and the liquid supplementing port and the gas supplementing port are both arranged in the middle of the tower body of the spray tower and are respectively used for supplementing alkali and nitrogen to be concentrated into the spray tower; the liquid caustic soda circulating system, the nitrogen circulating system and the spray tower are communicated through pipelines and are used for conveying liquid caustic soda and nitrogen to exchange heat, so that the loss of energy consumption in the liquid caustic soda concentration process is reduced, and the utilization rate of energy consumption is improved.

Furthermore, the spray tower is also provided with a liquid caustic soda circulation outlet, a liquid caustic soda circulation inlet, a nitrogen circulation outlet and a nitrogen circulation inlet, the nitrogen circulation outlet is arranged at the top of the spray tower, and the nitrogen circulation inlet is arranged at the middle lower part of the spray tower.

In the scheme, the liquid caustic soda circulating outlet is arranged at the middle lower part of the spray tower body, the liquid caustic soda circulating inlet is arranged at the upper part of the spray tower body, the nitrogen circulating inlet is arranged at the upper part of the liquid replenishing port, and liquid caustic soda in the spray tower is transmitted to other devices through the liquid caustic soda circulating outlet to exchange heat and then returns to the spray tower through the liquid caustic soda circulating inlet; and after the nitrogen carrying the moisture is transmitted to other devices through the nitrogen circulating outlet for heat exchange and condensation, the dry nitrogen is transmitted back to the spray tower through the nitrogen circulating inlet.

Further, the bottom of the spraying tower is arranged to be inverted cone-shaped, and the drain outlet is arranged at the bottom of the inverted cone-shaped.

In the above-mentioned scheme, set up the spray column bottom to the back taper, conveniently wash and sewage discharge, improve the result of use.

And further, the heat exchanger II comprises a first-effect heat exchanger, a second-effect heat exchanger and a third-effect heat exchanger which are sequentially communicated.

In the above scheme, the three-stage heat exchanger is arranged, so that the heat recovery effect can be improved, and the heat loss is reduced.

Further, a packing layer is arranged in the spray tower.

In the above-mentioned scheme, the concrete material of packing layer is the network structure that polytetrafluoroethylene worked out formed, is provided with the packing layer, can increase the evaporation area of moisture in the liquid caustic soda, improves concentration effect and speed, and polytetrafluoroethylene's material has corrosion-resistant effect, increase of service life.

Furthermore, a spray head is arranged in the spray tower, the spray head is communicated with the liquid caustic soda circulation inlet through a water distribution pipeline, and the spray head is arranged at the upper part of the packing layer.

In the above-mentioned scheme, the caustic soda liquid after will heating through the shower nozzle sprays the spray column in, can increase the evaporation area of caustic soda liquid, promotes the evaporation of water, improves concentration efficiency.

The liquid caustic soda concentration method adopting the liquid caustic soda concentration device comprises the following steps:

(1) filling nitrogen into the spray tower through the air supplementing port to replace the air in the spray tower; replenishing liquid caustic soda into the spray tower through a liquid replenishing port, wherein a ball float valve is arranged at the liquid replenishing port, and the liquid level is controlled through the ball float valve;

(2) pumping liquid caustic soda in a spray tower into a heat exchanger I by using a circulating pump, heating to 50 ℃, pumping the liquid caustic soda back to the spray tower, atomizing by using a spray head and a packing layer, transferring heat and mass between the liquid caustic soda and dry nitrogen in the spray tower, raising the temperature of the nitrogen to 50 ℃, and taking away water in the atomized liquid caustic soda under the action of surface partial pressure to form saturated wet nitrogen at 50 ℃;

(3) the saturated damp and hot nitrogen in the spray tower is sequentially pumped into an evaporator, a first-effect heat exchanger, a second-effect heat exchanger, a third-effect heat exchanger and a condenser by a fan, the temperature is reduced to 20 ℃, moisture in the damp and hot nitrogen is condensed to form condensate, and the condensed dry nitrogen is conveyed back into the spray tower for recycling;

(4) the temperature of the inlet water and the outlet water of the hot water side of the water source heat pump is 40/50 ℃, the temperature of the inlet water and the outlet water of the cold water side of the water source heat pump is 20/12 ℃, and the water body in the heat exchanger I is pumped into the water source heat pump by the hot water pump and then pumped back into the heat exchanger I, so that the liquid caustic soda is heated;

(5) a water body in the water source heat pump is sequentially pumped into the first-effect heat exchanger, the second-effect heat exchanger and the third-effect heat exchanger by using a cold water pump and then is pumped back into the water source heat pump, so that the temperature in the damp and hot nitrogen is recycled;

(6) the steps are carried out simultaneously, the circulation is repeated, and when the mass concentration of the caustic soda liquid meets the requirement, the caustic soda liquid is discharged through a liquid discharge port.

Further, the mass concentration of the liquid caustic soda in the step (2) is 28-32%.

Further, the mass concentration of the discharged liquid caustic soda in the step (6) is 37 to 39%.

In the above scheme, carry the moisture in the liquid caustic soda through nitrogen gas, realize the purpose with moisture recovery, liquid caustic soda is concentrated, utilize devices such as water source heat pump, heat exchanger one, heat exchanger to realize thermal conduction and recovery, reduce thermal loss.

The invention has the following effects:

the device provided by the invention is adopted to concentrate the liquid caustic soda from 30% to 38% in mass concentration, so that the energy consumption can be obviously saved, the energy loss is reduced, the whole concentration process is normal pressure concentration, the operation temperature of the equipment is low, and the overall safety performance is high.

Drawings

FIG. 1 is a schematic structural view of the present invention;

reference numerals: 1. a spray tower; 2. a fluid infusion port; 3. an air supplement port; 4. a liquid discharge port; 5. a sewage draining outlet; 6. a circulation pump; 7. a first heat exchanger; 8. a fan; 9. an evaporator; 10. a second heat exchanger; 11. a condenser; 12. a water source heat pump; 13. a hot water pump; 14. a cold water pump; 15. a liquid caustic soda circulation outlet; 16. a liquid caustic soda circulation inlet; 17. a nitrogen gas circulation outlet; 18. a nitrogen recycle inlet; 19. a primary heat exchanger; 20. a two-effect heat exchanger; 21. a triple-effect heat exchanger; 22. a filler layer; 23. and (4) a spray head.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings.

In an embodiment of the present invention, as shown in fig. 1, a caustic soda liquid concentrating apparatus is provided, which includes a spray tower 1, a caustic soda liquid circulating system and a nitrogen circulating system, wherein the spray tower 1 is provided with a liquid supplementing port 2, a gas supplementing port 3, a liquid discharging port 4 and a sewage discharging port 5, optimally, the bottom of the spray tower 1 is arranged in an inverted cone shape, and the sewage discharging port 5 is arranged at the bottom of the inverted cone shape. The liquid caustic soda circulating system and the nitrogen circulating system are respectively communicated with the spray tower 1; optimally, the spray tower 1 is also provided with a liquid caustic soda circulation outlet 15, a liquid caustic soda circulation inlet 16, a nitrogen circulation outlet 17 and a nitrogen circulation inlet 18, the nitrogen circulation outlet 17 is arranged at the top of the spray tower 1, and the nitrogen circulation inlet 18 is arranged at the middle lower part of the spray tower 1.

The liquid caustic soda circulating system comprises a circulating pump 6 and a first heat exchanger 7, and the circulating pump 6, the first heat exchanger 7 and the spray tower 1 are communicated in sequence through pipelines to form a loop; the nitrogen circulating system comprises a fan 8, an evaporator 9, a second heat exchanger 10 and a condenser 11, wherein the fan 8, the evaporator 9, the second heat exchanger 10, the condenser 11 and the spray tower 1 are communicated in sequence through pipelines to form a loop; optimally, the second heat exchanger 10 comprises a first-effect heat exchanger 19, a second-effect heat exchanger 20 and a third-effect heat exchanger 21 which are communicated in sequence.

The water source heat pump device is characterized by further comprising a water source heat pump 12, a hot water pump 13 is arranged between the first heat exchanger 7 and the water source heat pump 12, the first heat exchanger 7 and the water source heat pump 12 are communicated through a pipeline to form a loop, a cold water pump 14 is arranged between the water source heat pump 12 and the second heat exchanger 10, and the water source heat pump 12, the cold water pump 14 and the second heat exchanger 10 are communicated through pipelines to form a loop.

Optimally, a packing layer 22 is arranged in the spray tower 1. Optimally, a spray head 23 is arranged in the spray tower 1, the spray head 23 is communicated with the liquid caustic soda circulation inlet 16 through a water distribution pipeline, and the spray head 23 is arranged at the upper part of the packing layer 22.

The liquid caustic soda concentration method adopting the liquid caustic soda concentration device comprises the following steps:

(1) filling nitrogen into the spray tower through the air supplementing port to replace the air in the spray tower; replenishing liquid caustic soda into the spray tower through a liquid replenishing port, wherein a ball float valve is arranged at the liquid replenishing port, and the liquid level is controlled through the ball float valve;

(2) pumping liquid caustic soda with the mass concentration of 30% in the spray tower into the heat exchanger I by using a circulating pump, heating to 50 ℃, pumping the liquid caustic soda back to the spray tower, atomizing by using a spray head and a packing layer, transferring heat and mass between the liquid caustic soda and dry nitrogen in the spray tower, raising the temperature of the nitrogen to 50 ℃, and taking away moisture in the atomized liquid caustic soda to form saturated wet nitrogen at 50 ℃ under the action of surface partial pressure;

(3) the saturated damp and hot nitrogen in the spray tower is sequentially pumped into an evaporator, a first-effect heat exchanger, a second-effect heat exchanger, a third-effect heat exchanger and a condenser by a fan, the temperature is reduced to 20 ℃, moisture in the damp and hot nitrogen is condensed to form condensate, the condensate is collected, and the condensed dry nitrogen is conveyed back into the spray tower for recycling;

(4) the temperature of the inlet water and the outlet water of the hot water side of the water source heat pump is 40/50 ℃, the temperature of the inlet water and the outlet water of the cold water side of the water source heat pump is 20/12 ℃, and the water body in the heat exchanger I is pumped into the water source heat pump by the hot water pump and then pumped back into the heat exchanger I, so that the liquid caustic soda is heated;

(5) a water body in the water source heat pump is sequentially pumped into the first-effect heat exchanger, the second-effect heat exchanger and the third-effect heat exchanger by using a cold water pump and then is pumped back into the water source heat pump, so that the temperature in the damp and hot nitrogen is recycled;

(6) the steps are carried out simultaneously, the circulation is repeated, and when the mass of the liquid caustic soda reaches 38%, the liquid caustic soda is discharged through a liquid outlet.

Will be 5m³When the liquid caustic soda with the mass concentration of 30% and the initial temperature of 47.2 ℃ is concentrated to the mass concentration of 38%, 1397.9kg of water needs to be evaporated, the device and the method are adopted for concentration, the system input power is 20KW, the power consumption is 1026kWh, the weight of the converted standard coal is 0.126 ton, the traditional steam evaporation process is adopted, the temperature of steam is 152 ℃, the gasification heat value of the water is 2260kJ/kg, the required steam is 15.735 ton, and the weight of the converted standard coal is 1.71 ton.