CN111426148A - A method for reducing air separation energy consumption by utilizing gasifier flash low-pressure steam refrigeration - Google Patents

Abstract

The invention provides a method for reducing the energy consumption of air separation by utilizing flashing low-pressure steam in a gasifier for refrigeration. The method for reducing the energy consumption of air separation by flashing low-pressure steam in a gasifier includes the following steps: S1. After the gray water at the bottom of the gasifier enters a high-pressure flash tank to be flashed, it enters a low-pressure flash tank for further flashing . The invention provides a method for reducing the energy consumption of air separation by utilizing the flashing low-pressure steam of a gasifier to cool down the energy consumption of air separation. By utilizing the flashing low-pressure steam of a gasifier and a lithium bromide solvent to form a lithium bromide absorption refrigerator, lithium bromide freezing water is prepared, and the freezing water is refrigerated in the air separation. The water heat exchanger exchanges heat with the chilled water from the water cooling tower. After cooling the chilled water, it enters the ammonia evaporator for further cooling, which reduces the liquid ammonia consumption of the ammonia evaporator and reduces the load of the ammonia evaporator; lithium bromide The solution is recycled, making full use of the waste heat of the low-pressure steam flashing in the vaporizer, and at the same time reducing the consumption of liquid ammonia in the air separation pre-cooling system, and the energy consumption is reduced.

Description

A method for reducing air separation energy consumption by utilizing gasifier flash low-pressure steam refrigeration

technical field

The invention relates to the field of reducing energy consumption of air separation plants, in particular to a method for reducing energy consumption of air separation by utilizing flashing low-pressure steam in a gasifier for refrigeration.

Background technique

In the air separation plant, due to the relatively large demand for nitrogen, the regeneration of the molecular sieve adsorber also requires a large part of the dirty nitrogen, and the dirty nitrogen available for the water cooling tower is seriously insufficient. Therefore, it is necessary to set up a chiller so that the temperature of the air out of the air cooling tower is not higher than 17 ℃, so as to ensure that the volume of the molecular sieve adsorber will not be too large and normal production.

The design temperature of the chilled water in the outlet cooling tower is 16.3°C, and the design temperature of the inlet water at the upper part of the air cooling tower is 10°C, so as to ensure that the air temperature of the outlet air cooling tower reaches the design value of 12°C. This requires the ammonia evaporator to have sufficient heat exchange capacity, and its liquid ammonia consumption is 6136Kg/h; the liquid ammonia consumption is very large, which has a great impact on the load of the ice machine, which increases the load of the ice machine.

Therefore, it is necessary to provide a method for reducing the energy consumption of air separation by utilizing flashing low-pressure steam in a gasifier to solve the above-mentioned technical problems.

SUMMARY OF THE INVENTION

The invention provides a method for reducing the energy consumption of air separation by utilizing the flashing low-pressure steam of a gasifier for refrigeration, which solves the problem of large consumption of liquid ammonia, great influence on the load of the ice machine, and aggravation of the load of the ice machine.

In order to solve the above-mentioned technical problems, the method for reducing air separation energy consumption by utilizing gasifier flash low-pressure steam refrigeration provided by the present invention comprises the following steps:

S1. After the gray water at the bottom of the vaporization furnace enters the high-pressure flash tank to be flashed, it enters the low-pressure flash tank for further flashing;

S2. The flashed low-pressure steam at the top of the low-pressure flash tank enters the lithium bromide absorption refrigeration unit, and the dilute solution of lithium bromide is heated in the generator to be concentrated into a concentrated solution, and refrigerant steam is generated simultaneously;

S3, and then discharge the refrigerant vapor in S2 into the condenser, and then it will be condensed into refrigerant water by the cooling water flowing through the heat transfer tube of the condenser;

S4, and then the refrigerant water is throttled through the U-shaped pipe and then discharged to the evaporator, and then flows into the evaporator refrigerant water tray after flashing and cooling in the evaporator;

S5. The refrigerant water entering the refrigerant water pan of the evaporator is pumped out by the refrigerant water pump, and then the refrigerant water pumped out is sprayed on the surface of the evaporator heat transfer pipe by the refrigerant water pump to absorb the heat of the cold water in the heat transfer pipe. Boiling and evaporation to form refrigerant vapor;

S6. By discharging the refrigerant vapor into the absorber, it will be absorbed by the concentrated solvent returning to the absorber, and the concentrated solvent will absorb the refrigerant vapor and become a dilute solvent, and then enter the generator to be heated concentrate;

S7. After the cold water enters the evaporator, the heat is exchanged by the refrigerant water, which reduces the temperature, and then is pressurized by the water pump and sent to the shell side of the chilled water heat exchanger of the air separation pre-cooling system, and is connected with the freezing water in the tube side. The chilled water of the pump exchanges heat, and after the cold water is exchanged by the heat exchanger, the temperature rises and returns to the generator to cool down for recycling;

S8. The circulating water enters from the upper part of the water-cooling tower through the replenishment valve, and transfers heat and mass with the sewage nitrogen entering from the lower part of the water-cooling tower. After the lithium bromide cold water heat exchange in the process, its temperature is lowered, and the chilled water of the discharged chilled water heat exchanger enters the tube side of the ammonia evaporator to exchange heat with the liquid ammonia in the shell side, and the temperature is further lowered into the upper part of the air cooling tower , to provide cooling water for the air cooling tower;

The 32℃ water-cooling tower C41102 makes up water, enters from the upper part of the water-cooling tower C41102 through the replenishment valve, transfers mass and heat with the sewage nitrogen entering from the lower part of the water-cooling tower C41102, and is cooled to 16.3 ℃ and then pumped out. After being pressurized by the chilled water pump P41102, it enters the The tube side of the chilled water heat exchanger exchanges heat with the lithium bromide cold water on the shell side and the temperature drops to 11°C; the chilled water exiting the chilled water heat exchanger enters the ammonia evaporator and exchanges heat with the liquid ammonia on the shell side. After being cooled to 9℃, it enters the upper part of the air-cooling tower; provides cooling water for the air-cooling tower;

The liquid ammonia consumption of the ammonia evaporator was reduced from 6136Kg/h to 1837Kg/h, which reduced the 3.8MPa steam consumption of the ammonia compressor by 0.8 tons per hour; at the same time, the air temperature of the outlet cooling tower was reduced from 12°C to 10°C; The inlet temperature of the compressor is reduced, the load of the supercharger is reduced, and the 9.0MPa steam consumption of the driving machine steam turbine is reduced by 0.1 ton/h; the temperature of the air entering the cold box is reduced, the cooling loss of the device is reduced, and the liquid output is increased every day. 5 tons of liquid oxygen; if 3.8MPa steam is charged at 100 yuan, if 9.0MPa steam is charged at 120 yuan, and liquid oxygen is 700 yuan, so one day can increase profit: 0.8*100*24+0.1*120*24+ 5*700=5708 yuan.

Preferably, the temperature of the flashed low-pressure steam in S2 is 140-150°C.

Preferably, the temperature is lowered to 16.3°C-17.5°C in the S8.

Preferably, a chilled water heat exchanger is added between the outlet of the chilled water pump and the ammonia evaporator.

Preferably, the heat exchange area of the chilled water heat exchanger is 700m ³ , the lithium bromide chilled water is carried on the shell side, and the design pressure is 0.6Mpa.

Preferably, the design pressure of the chilled water coming from the chilled water pump on the tube side is 1.3Mpa.

Preferably, the chilled water heat exchanger is provided with a bypass valve, and an exhaust valve is provided at the high point of the pipeline of the chilled water into the heat exchanger.

The present invention also provides a chilled water pump installation assembly, comprising a chilled water pump body and a mounting plate, a movable box is fixedly connected to the top of the mounting plate, and a rotating shaft is rotatably connected between the top and bottom of the inner wall of the movable box, so A first bevel gear and a rotating plate are fixedly connected to the outer surface of the rotating shaft in sequence from top to bottom, and L-shaped limit blocks are provided on both sides of the bottom of the chilled water pump body.

Preferably, sliding plates are slidably connected to both sides of the bottom of the inner wall of the inner wall of the movable box, L-shaped clamping blocks are fixedly connected to the tops of the two sliding plates, and two sliding plates are rotatably connected to the top of the rotating plate. There are two driving rods, and the other ends of the two driving rods are respectively rotatably connected to the tops of the two sliding plates.

Preferably, a rotating shaft is rotatably connected to the back of the inner wall of the movable box, a second bevel gear meshing with the first bevel gear is fixedly connected to the outer surface of the rotating shaft, and one end of the rotating shaft penetrates through the the movable box and extend to the outside of the movable box.

Compared with the related art, the method for reducing air separation energy consumption by utilizing gasifier flash low-pressure steam refrigeration provided by the present invention has the following beneficial effects:

The invention provides a method for reducing the energy consumption of air separation by flashing low-pressure steam in a gasifier. The consumption is relatively large, especially in the start-up stage, when the rectification system does not produce polluted nitrogen, the water-cooling tower basically has no cooling effect, and the temperature of the chilled water is the same as the make-up water temperature of the water-cooled tower; Provided by the ammonia evaporator, the liquid ammonia consumption of the ammonia evaporator is larger, and it is difficult to reduce the water temperature to the required process range. After adding the chilled water heat exchanger, the load of the ammonia evaporator can be greatly reduced. , and can reduce the air temperature of the air cooling tower to the design value of 12 °C;

Lithium bromide chilled water is prepared by flashing low-pressure steam and lithium bromide solvent in a gasifier to form a lithium bromide absorption refrigerator. After the water is cooled, it enters the ammonia evaporator for further cooling, which greatly reduces the liquid ammonia consumption of the ammonia evaporator and reduces the load of the ammonia evaporator. The lithium bromide solution is recycled, which makes full use of the waste heat of the low-pressure steam flashing in the vaporizer, and also reduces the consumption of liquid ammonia in the air separation pre-cooling system, and the energy consumption is reduced.

Description of drawings

1 is a schematic structural diagram of a preferred embodiment of a method for reducing air separation energy consumption by utilizing gasifier flash low-pressure steam refrigeration provided by the present invention;

Fig. 2 is the process flow diagram of the pre-cooling system shown in Fig. 1;

3 is a schematic structural diagram of a preferred embodiment of the chilled water pump installation assembly provided by the present invention;

FIG. 4 is a cross-sectional plan view of the movable box shown in FIG. 3 .

Labels in the figure: 1. Measuring point of cold water inlet temperature, 2. Cold water outlet temperature, 3. Cooling water inlet temperature, 4. Steam condensate temperature, 5. Spray temperature of concentrated solution, 6. Outlet temperature of concentrated solution, 7. Condensation Temperature, 8. Evaporation temperature, 9. Melting tube temperature, 10. Cold water flow rate, 11. Self-pumping device pressure, 12. Steam pressure, 13. Automatic exhaust device pressure, 14. Chilled water pump body, 15. Mounting plate, 16, movable box, 17, rotating shaft, 18, first bevel gear, 19, rotating plate, 20, L-shaped limit block, 21, sliding plate, 22, L-shaped clamping block, 23, drive rod, 24, Rotating shaft, 25, second bevel gear.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and embodiments.

Please refer to FIG. 1, FIG. 2, FIG. 3 and FIG. 4, wherein, FIG. 1 is a schematic structural diagram of a preferred embodiment of the method for reducing air separation energy consumption by utilizing gasifier flash low-pressure steam refrigeration provided by the present invention Fig. 2 is the pre-cooling system process flow chart shown in Fig. 1; Fig. 3 is the structural representation of a kind of preferred embodiment of chilled water pump installation assembly provided by the present invention; Fig. 4 is the section of the movable box shown in Fig. 3 Top view. The method for reducing air separation energy consumption by utilizing gasifier flash low-pressure steam refrigeration includes the following steps:

S1. After the gray water at the bottom of the vaporization furnace enters the high-pressure flash tank to be flashed, it enters the low-pressure flash tank for further flashing;

S2. The flashed low-pressure steam at the top of the low-pressure flash tank enters the lithium bromide absorption refrigeration unit, and the dilute solution of lithium bromide is heated in the generator to be concentrated into a concentrated solution, and refrigerant steam is generated simultaneously;

S3, and then discharge the refrigerant vapor in S2 into the condenser, and then it will be condensed into refrigerant water by the cooling water flowing through the heat transfer tube of the condenser;

S4, and then the refrigerant water is throttled through the U-shaped pipe and then discharged to the evaporator, and then flows into the evaporator refrigerant water tray after flashing and cooling in the evaporator;

S5. The refrigerant water entering the refrigerant water pan of the evaporator is pumped out by the refrigerant water pump, and then the refrigerant water pumped out is sprayed on the surface of the evaporator heat transfer pipe by the refrigerant water pump to absorb the heat of the cold water in the heat transfer pipe. Boiling and evaporation to form refrigerant vapor;

S6. By discharging the refrigerant vapor into the absorber, it will be absorbed by the concentrated solvent returning to the absorber, and the concentrated solvent will absorb the refrigerant vapor and become a dilute solvent, and then enter the generator to be heated concentrate;

S7. After the cold water enters the evaporator, the heat is exchanged by the refrigerant water, which reduces the temperature, and then is pressurized by the water pump and sent to the shell side of the chilled water heat exchanger of the air separation pre-cooling system, and is connected with the freezing water in the tube side. The chilled water of the pump exchanges heat, and after the cold water is exchanged by the heat exchanger, the temperature rises and returns to the generator to cool down for recycling;

S8. The circulating water enters from the upper part of the water-cooling tower through the replenishment valve, and transfers heat and mass with the sewage nitrogen entering from the lower part of the water-cooling tower. After the lithium bromide cold water heat exchange in the process, its temperature is lowered, and the chilled water of the discharged chilled water heat exchanger enters the tube side of the ammonia evaporator to exchange heat with the liquid ammonia in the shell side, and the temperature is further lowered into the upper part of the air cooling tower , to provide cooling water for the air cooling tower;

The chilled water of the pre-cooling system of the air separation unit is cooled by the water-cooling tower and the ammonia evaporator, which consumes a large amount of liquid ammonia; especially in the start-up stage, when the rectification system does not produce dirty nitrogen, the water-cooling tower basically There is no cooling effect, the temperature of the chilled water is the same as the temperature of the make-up water of the water-cooling tower (usually about 30 ℃); all the cooling capacity required for the cooling of the chilled water is provided by the ammonia evaporator, and the ammonia evaporator consumes more liquid ammonia, And it is difficult to reduce the water temperature to the required process range; after adding the chilled water heat exchanger, the load of the ammonia evaporator can be greatly reduced, and the air temperature of the air cooling tower can be reduced to the design value of 12 ° C ;

The ammonia evaporator used in this air separation plant is used as a heat exchanger for further cooling the chilled water, so that it can meet the cooling water in the upper section of the air cooling tower. Liquid ammonia from a synthetic ammonia compressor is used as a refrigerant. The medium-pressure liquid ammonia is decompressed (and cooled) through the throttle valve and enters the ammonia evaporator, which absorbs heat and vaporizes, absorbs the heat of the chilled water, and further cools the chilled water. The vaporized gaseous ammonia is recycled after being compressed and condensed at the inlet of the ammonia compressor;

The water cooling tower is the water cooling tower C41102, the chilled water pump is the chilled water pump P41102, the ammonia evaporator is the ammonia evaporator E41101, and the inlet and outlet pipes are DN200.

The 32°C water-cooling tower make-up water enters from the upper part of the water-cooling tower through the make-up valve, and transfers heat and mass with the sewage nitrogen entering from the lower part of the water-cooling tower. It is cooled to 16.3°C and then pumped out. The tube side of the heater exchanges heat with the lithium bromide cold water on the shell side and the temperature drops to 11°C; the chilled water from the chilled water heat exchanger enters the tube side of the ammonia evaporator and exchanges heat with the liquid ammonia on the shell side, and the temperature is reduced to Enter the upper part of the air-cooling tower after 9 ℃; provide cooling water for the air-cooling tower;

The liquid ammonia consumption of the ammonia evaporator was reduced from 6136Kg/h to 1837Kg/h, which reduced the 3.8MPa steam consumption of the ammonia compressor by 0.8 tons per hour; at the same time, the air temperature of the outlet cooling tower was reduced from 12°C to 10°C; The inlet temperature of the compressor is reduced, the load of the supercharger is reduced, and the 9.0MPa steam consumption of the driving machine steam turbine is reduced by 0.1 ton/h; the temperature of the air entering the cold box is reduced, the cooling loss of the device is reduced, and the liquid output is increased every day. 5 tons of liquid oxygen; if 3.8MPa steam is charged at 100 yuan, if 9.0MPa steam is charged at 120 yuan, and liquid oxygen is 700 yuan, so one day can increase profit: 0.8*100*24+0.1*120*24+ 5*700=5708 yuan.

Preferably, the temperature of the flashed low-pressure steam in S2 is 140-150°C.

Preferably, the temperature is lowered to 16.3°C-17.5°C in the S8.

Preferably, a chilled water heat exchanger is added between the outlet of the chilled water pump and the ammonia evaporator;

A chilled water heat exchanger is added between the outlet of the chilled water pump and the ammonia evaporator for heat exchange between chilled water and lithium bromide cold water.

Preferably, the heat exchange area of the chilled water heat exchanger is 700m ³ , the lithium bromide chilled water is carried on the shell side, and the design pressure is 0.6Mpa.

Preferably, the design pressure of the chilled water coming from the chilled water pump on the tube side is 1.3Mpa.

Preferably, the chilled water heat exchanger is provided with a bypass valve, and an exhaust valve is provided at the high point of the pipeline where the chilled water enters the heat exchanger;

The chilled water heat exchanger is equipped with a bypass valve. If no lithium bromide cold water is supplied or the heat exchanger is overhauled, the bypass valve of the chilled water heat exchanger can be opened, and the hand valve of the chilled water in and out of the chilled water heat exchanger can be closed to exchange the chilled water. The heat exchanger is cut off; at the same time, there is a shell side exhaust valve on the chilled water heat exchanger, and an exhaust valve is provided at the high point of the pipeline where the chilled water enters the heat exchanger, so that the chilled water heat exchanger can be exhausted when the chilled water heat exchanger is put into use. And the air in the heat exchanger to ensure the heat exchange effect of the chilled water heat exchanger. There is a guide shower at the low point of the heat exchanger and the pipeline, which is used to drain the accumulated water in the heat exchanger and the pipeline after the chilled water heat exchanger is out of operation.

The working principle of the method for reducing air separation energy consumption by utilizing gasifier flash low-pressure steam refrigeration provided by the present invention is as follows:

After the grey water at the bottom of the vaporization furnace enters the high pressure flash tank to be flashed, it enters the low pressure flash tank for further flash evaporation;

The flashed low-pressure steam at the top of the low-pressure flash tank enters the lithium bromide absorption refrigeration unit, and the dilute lithium bromide solution is heated in the generator to concentrate it into a concentrated solution, and refrigerant vapor is generated at the same time;

Then, the refrigerant vapor in S2 is discharged into the condenser, and then it will be condensed into refrigerant water by the cooling water flowing through the heat transfer tube of the condenser;

The refrigerant water is then throttled through the U-shaped pipe and then discharged to the evaporator, and then flows into the evaporator refrigerant water tray after flashing and cooling in the evaporator;

The refrigerant water entering the refrigerant water pan of the evaporator is pumped out by the refrigerant water pump, and then the refrigerant water pumped out is sprayed on the surface of the evaporator heat transfer pipe by the refrigerant water pump to absorb the heat of the cold water in the heat transfer pipe for boiling and heating. Evaporate to form refrigerant vapor;

Then, by discharging the refrigerant vapor into the absorber, it will be absorbed by the concentrated solvent returning to the absorber, and the concentrated solvent will absorb the refrigerant vapor and become a dilute solvent, and then enter the generator to be heated and concentrated;

The heat of the cold water entering the evaporator is exchanged by the refrigerant water, which reduces the temperature, and then is pressurized by the water pump and sent to the shell side of the chilled water heat exchanger of the air separation pre-cooling system, and is connected with the chilled water pump in the tube side. Chilled water heat exchange, after the cold water is heated by the heat exchanger, the temperature rises and returns to the generator to cool down for recycling;

The circulating water enters from the upper part of the water-cooling tower through the replenishment valve, and transfers heat and mass with the sewage nitrogen entering from the lower part of the water-cooling tower. After the lithium bromide cold water heat exchange, its temperature is lowered, and the chilled water of the discharged chilled water heat exchanger enters the tube side of the ammonia evaporator and exchanges heat with the liquid ammonia in the shell side, and the temperature is further lowered into the upper part of the air cooling tower, which is Air cooling towers provide cooling water.

Compared with the related art, the method for reducing air separation energy consumption by utilizing gasifier flash low-pressure steam refrigeration provided by the present invention has the following beneficial effects:

The chilled water of the pre-cooling system of the air separation unit is cooled by the water-cooling tower and the ammonia evaporator, which consumes a large amount of liquid ammonia, especially in the start-up stage, when the rectification system does not produce dirty nitrogen, the water-cooling tower basically There is no cooling effect, and the temperature of the chilled water is the same as the temperature of the make-up water of the water-cooling tower; all the cooling capacity required for the cooling of the chilled water is provided by the ammonia evaporator, which consumes more liquid ammonia, and it is difficult to reduce the water temperature. Within the required process range, after adding the chilled water heat exchanger, the load of the ammonia evaporator can be greatly reduced, and the air temperature of the air cooling tower can be reduced to the design value of 12 °C;

Lithium bromide chilled water is prepared by flashing low-pressure steam and lithium bromide solvent in a gasifier to form a lithium bromide absorption refrigerator. After the water is cooled, it enters the ammonia evaporator for further cooling, which greatly reduces the liquid ammonia consumption of the ammonia evaporator and reduces the load of the ammonia evaporator. The lithium bromide solution is recycled, which makes full use of the waste heat of the low-pressure steam flashing in the vaporizer, and also reduces the consumption of liquid ammonia in the air separation pre-cooling system, and the energy consumption is reduced.

Please refer to FIGS. 3-4 in conjunction. In addition, the present invention also provides a chilled water pump installation assembly for installing a chilled water pump for a method for reducing air separation energy consumption by flashing low-pressure steam in a gasifier, including a chilled water pump body 14 and a mounting plate 15, the top of the mounting plate 15 is fixedly connected with a movable box 16, and a rotating shaft 17 is rotatably connected between the top and bottom of the inner wall of the movable box 16, and the outer surface of the rotating shaft 17 is from above. The first bevel gear 18 and the rotating plate 19 are fixedly connected in sequence from the bottom, and L-shaped limit blocks 20 are provided on both sides of the bottom of the chilled water pump body 14;

The setting of the L-shaped limit block 20 is mainly to facilitate the clamping between the chilled water pump body 14 and the two L-shaped clamping blocks 22 inside the movable box 16 to complete the connection relationship, and the mounting plate 15 at the bottom of the movable box 16 is connected to the outside world. Fixed installation of the car.

Both sides of the bottom of the inner wall of the inner wall of the movable box 16 are slidably connected with sliding plates 21 , the tops of the two sliding plates 21 are fixedly connected with L-shaped clamping blocks 22 , and the tops of the rotating plates 19 are rotatably connected. There are two driving rods 23, and the other ends of the two driving rods 23 are respectively connected to the tops of the two sliding plates 21 in rotation;

Through the movement of the two sliding plates 21 relative to or away from each other, the two L-shaped clamping blocks 22 can be driven to move in the opposite direction or away from each other. The two L-shaped limit blocks 20 inside the movable box 16 are clamped, and then the installation of the chilled water pump body 14 is completed. insert.

A rotating shaft 24 is rotatably connected to the back of the inner wall of the movable box 16 , and a second bevel gear 25 meshing with the first bevel gear 18 is fixedly connected to the outer surface of the rotating shaft 24 . One end penetrates through the movable box 16 and extends to the outside of the movable box 16;

By driving the rotation of the rotating shaft 24, the first bevel gear 18 and the second bevel gear 25 can be driven to rotate, thereby driving the rotating shaft 17 to rotate, and the rotation of the rotating shaft 17 will drive the rotating plate 19 to rotate, and the rotation The rotation of the plate 19 will drive the two driving rods 23 to expand and contract. Through the expanding and contracting movements of the two driving rods 23, two sliding plates 21 and two L-shaped clamping blocks 22 can be driven. Move in the opposite direction or the opposite direction, and then the two L-shaped limit blocks 20 inside the movable box 16 can be clamped to complete the installation, and the two L-shaped limit blocks 20 inside the movable box 16 can be lost. Clamping, complete disassembly, simple operation, more convenient to use, convenient for staff to maintain the chilled water pump, and only need to operate one step, it can continuously drive other components to complete installation and disassembly, saving time and effort.

The specific structure of the chilled water pump installation assembly refers to the above-mentioned embodiments. Since the chilled water pump installation assembly adopts all the technical solutions of the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments. I won't repeat them one by one.

The above descriptions are only the embodiments of the present invention, and are not intended to limit the scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied to other related technologies Fields are similarly included in the scope of patent protection of the present invention.

Claims (10)

1. A method for reducing air separation energy consumption by utilizing flash evaporation low-pressure steam refrigeration of a gasification furnace is characterized by comprising the following steps:

s1, allowing the grey water at the bottom of the vaporizing furnace to enter a high-pressure flash tank for flash evaporation, and allowing the grey water to enter a low-pressure flash tank for further flash evaporation;

s2, feeding the flash evaporation low-pressure steam at the top of the low-pressure flash evaporation tank into a lithium bromide absorption refrigerating unit, heating the lithium bromide dilute solution in a generator to concentrate the lithium bromide dilute solution into a concentrated solution, and generating refrigerant steam at the same time;

s3, discharging the refrigerant steam in S2 into a condenser, and condensing the refrigerant steam into refrigerant water by cooling water flowing through a heat transfer pipe of the condenser;

s4, throttling the refrigerant water through the U-shaped pipe, discharging the refrigerant water to the evaporator, and flashing and cooling the refrigerant water in the evaporator to flow into a refrigerant water tray of the evaporator;

s5, pumping out the refrigerant water entering the refrigerant water tray of the evaporator by a refrigerant water pump, spraying the pumped refrigerant water on the surface of a heat transfer pipe of the evaporator by the refrigerant water pump, absorbing the heat of cold water in the heat transfer pipe, and boiling and evaporating to form refrigerant steam;

s6, discharging the refrigerant steam into the absorber, absorbing the refrigerant steam by the rich solvent returned to the absorber, changing the rich solvent into the dilute solvent after absorbing the refrigerant steam, and then heating and concentrating the refrigerant steam in the generator;

s7, after heat of cold water entering the evaporator is exchanged by refrigerant water, the temperature is reduced, the cold water is pressurized by a water pump and then is sent to the shell side of a chilled water heat exchanger of the air separation pre-cooling system, the cold water exchanges heat with chilled water of a chilled water pump in a tube side, after heat exchange of the cold water by the heat exchanger, the temperature of the cold water is raised and returns to the generator for cooling, and the cold water is recycled;

and S8, circulating water enters from the upper part of the water cooling tower through a water replenishing valve, is subjected to mass and heat transfer with waste nitrogen gas entering from the lower part of the water cooling tower, is cooled, is pressurized by a refrigerating water pump, enters the tube pass of the chilled water heat exchanger, is subjected to heat exchange with lithium bromide cold water in the shell pass to lower the temperature of the chilled water, enters the tube pass of the ammonia evaporator to exchange heat with liquid ammonia in the shell pass, is further cooled, enters the upper part of the air cooling tower, and provides cooling water for the air cooling tower.

2. The method for reducing the energy consumption of air separation by utilizing the refrigeration of the flash low-pressure steam of the gasification furnace as claimed in claim 1, wherein the temperature of the flash low-pressure steam in S2 is 140-150 ℃.

3. The method for reducing the energy consumption of air separation by utilizing the flash evaporation low-pressure steam refrigeration of the gasification furnace as claimed in claim 1, wherein the temperature in the S8 is reduced to 16.3-17.5 ℃.

4. The method for reducing air separation energy consumption by utilizing gasification furnace flash evaporation low-pressure steam refrigeration as claimed in claim 1, wherein a chilled water heat exchanger is added between the outlet of the chilled water pump and the ammonia evaporator.

5. The method for reducing air separation energy consumption by utilizing gasification furnace flash evaporation low-pressure steam refrigeration as claimed in claim 1, wherein the heat exchange area of the chilled water heat exchanger is 700m³And the shell pass is filled with lithium bromide chilled water, and the design pressure is 0.6 MPa.

6. The method for reducing the energy consumption of air separation by utilizing the flash evaporation low-pressure steam refrigeration of the gasification furnace as claimed in claim 1, wherein the design pressure of the chilled water from the pipe pass chilled water pump is 1.3 Mpa.

7. The method for reducing the energy consumption of air separation by utilizing the flash evaporation low-pressure steam refrigeration of the gasification furnace as claimed in claim 1, wherein the chilled water heat exchanger is provided with a bypass valve, and an exhaust valve is arranged at the high point of a pipeline of the chilled water inlet heat exchanger.

8. The chilled water pump mounting assembly is used for mounting the chilled water pump of the method for reducing air separation energy consumption by utilizing gasification furnace flash evaporation low-pressure steam refrigeration according to any one of claims 1 to 7, and comprises a chilled water pump body and a mounting plate, wherein a movable box is fixedly connected to the top of the mounting plate, a rotating shaft is rotatably connected between the top and the bottom of the inner wall of the movable box, a first bevel gear and a rotating plate are fixedly connected to the outer surface of the rotating shaft from top to bottom in sequence, and L type limiting blocks are arranged on two sides of the bottom of the chilled water pump body.

9. The chilled water pump installation assembly according to claim 8, wherein sliding plates are slidably connected to both sides of the bottom of the inner wall of the movable box, L-type clamping blocks are fixedly connected to the tops of the two sliding plates, two driving rods are rotatably connected to the top of the rotating plate, and the other ends of the two driving rods are rotatably connected to the tops of the two sliding plates.

10. The chilled water pump mounting assembly according to claim 8, wherein a rotating shaft is rotatably connected to a rear surface of an inner wall of the movable box, a second bevel gear engaged with the first bevel gear is fixedly connected to an outer surface of the rotating shaft, and one end of the rotating shaft penetrates through the movable box and extends to the outside of the movable box.

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