Air separation air cooling tower refrigerating device for coal chemical industry enterprise

Abstract

The invention discloses an air separation air cooling tower refrigeration device for coal chemical industry enterprises, comprising: an air cooling tower comprising a tower main body, a gas outlet pipeline, a cooling water pipeline and an air cooling tower water return pipeline; a gas outlet pipeline is arranged at the top of the tower body, the tower body is provided with a cooling water pipeline and an air compressor pipeline, the cooling water pipeline is connected with the water cooling tower through a first valve, a cooling water pump set is arranged on a pipeline between the first valve and the water cooling tower, and an air cooling tower water return pipeline is arranged at the bottom of the tower body; a heat source inlet is connected with a hot water tank through a hot water pipeline, and a hot water pump set is arranged on the hot water pipeline. The front end of the first valve is provided with a cooling water inlet pipeline connected with a cooling water inlet of the lithium bromide refrigeration water chilling unit, and the rear end of the first valve is provided with a connecting pipe connected with a chilled water outlet of the first valve. A hot water outlet of the lithium bromide refrigeration water chilling unit is connected with a boiler liquid discharge pool; the connecting pipe is provided with at least one valve, and the hot water pipeline is provided with a second valve. The method is suitable for large-scale industrial popularization.

Description

Technical Field

[0001] The invention relates to the field of refrigeration units utilizing waste heat, and in particular to an air separation and air cooling tower refrigeration device used in coal chemical enterprises. Background Art

[0002] As the country puts forward the strategic goal of "carbon peak and carbon neutrality" for coal chemical enterprises, these enterprises are facing tremendous pressure to save energy and reduce carbon emissions. Coal chemical enterprises are major carbon emitters, especially with the continuous maturity of the domestic carbon market, which has dramatically increased their operating costs. However, coal chemical enterprises increase energy efficiency by recycling waste heat resources. On the one hand, they can relatively reduce carbon emissions. On the other hand, the carbon reduction effect generated by the recycling of waste heat resources can also partially offset carbon emissions. Therefore, coal chemical enterprises urgently need to develop new energy use scenarios to improve the deep recycling and utilization of waste heat resources in the production of coal chemical enterprises and improve the energy efficiency of coal chemical enterprises.

[0003] At present, in the coal-to-methanol, olefins, synthetic ammonia, ethylene glycol, acetic acid, ethanol and other processes of coal chemical enterprises, since the condensate discharged from the boiler of the conversion device is about 10t / h, the condensate discharged from the boiler of the water-steam area is about 5t / h, the condensate discharged from the synthetic steam drum is about 2t / h, and the steam condensate discharged from the expansion tank of the steam pipe network on the west side of the conversion is about 3t / h, the temperature is all 90℃-95℃, so the condensate discharged from the sewage of the coal-to-methanol, olefins, synthetic ammonia, ethylene glycol, acetic acid, ethanol and other systems contains a large amount of waste heat that can be utilized. In the actual production system, these condensates are directly discharged into the ditch and the circulating water pool after treatment, which not only wastes most of the sensible heat in the condensate, but also needs to be cooled down with circulating water for further treatment, increasing the load of the circulating water station. In addition, under high temperature conditions in summer, as the ambient temperature rises, the outlet air temperature of the air-cooling tower in the air separation unit increases significantly, approaching the interlocking temperature (16°C), and urgently needs to be cooled. Therefore, lowering the outlet air temperature of the air-cooling tower under high temperature conditions in summer has great practical significance for improving the economic benefits of coal-to-methanol, olefins, synthetic ammonia, ethylene glycol, acetic acid, ethanol and other processes.

[0004] Therefore, if a new equipment can be developed to comprehensively utilize the thermal energy of the waste liquid in the processes of coal-to-methanol, olefins, synthetic ammonia, ethylene glycol, acetic acid, ethanol, etc., and at the same time reduce the air temperature at the outlet of the air cooling tower in the air separation unit, this will have far-reaching significance, not only helping to save energy, but also improving refrigeration efficiency. Summary of the invention

[0005] The current problem is that the temperature of condensate and sewage in the production system of coal-to-methanol, olefins, synthetic ammonia, ethylene glycol, acetic acid, ethanol and other systems can reach 90℃-95℃, resulting in a large amount of waste heat waste and increased load on the circulating water station.

[0006] In order to solve the above technical problems, the present application provides an air separation air-cooling tower refrigeration device for coal chemical enterprises, including: an air-cooling tower, including a tower body, a gas outlet pipeline, a cooling water pipeline and an air-cooling tower return pipeline; a gas outlet pipeline is provided on the top of the tower body, and a cooling water pipeline and an air compressor pipeline are provided on the tower body of the tower body. The cooling water pipeline is connected to the water-cooling tower through a first valve, and a cooling water pump group is provided on the pipeline between the first valve and the water-cooling tower, and an air-cooling tower return pipeline is provided at the bottom of the tower body; a lithium bromide refrigeration chiller, a heat source inlet is connected to a hot water tank in an original production system through a hot water pipeline, and a hot water pump group is provided on the hot water pipeline; a cooling water inlet pipeline is provided at the front end of the first valve to connect the cooling water inlet of the lithium bromide refrigeration chiller; a connecting pipe is provided at the rear end of the first valve to connect the chilled water outlet of the lithium bromide refrigeration chiller; the hot water outlet of the lithium bromide refrigeration chiller is connected to a boiler drainage pool; wherein at least one valve is provided on the connecting pipe, and a second valve is provided on the hot water pipeline.

[0007] According to the embodiment of the present application, the lithium bromide refrigeration chiller is an intelligent hot water type lithium bromide refrigeration unit with a PLC control box, a liquid crystal display operation panel, and automatic / manual dual-mode.

[0008] According to an embodiment of the present application, a lithium bromide refrigeration chiller includes a generator, a condenser, an absorber, a condenser evaporator and an ORC expander module.

[0009] According to an embodiment of the present application, the tube-side inlet of the absorber is connected to the cooling water supply pipe, and the tube-side outlet of the condenser is connected to the cooling water return pipe.

[0010] According to an embodiment of the present application, the cooling water pump group and the hot water pump group are both double pump groups connected in parallel, and each pump group has multiple valves connected in series.

[0011] According to an embodiment of the present application, the chilled water is soft water.

[0012] According to an embodiment of the present application, the hot water tank is connected to the boiler fixed discharge pipe, synthetic sewage discharge pipe and sewage condensate discharge pipe of the coal chemical enterprise production system.

[0013] According to an embodiment of the present application, a regulating valve group and a condensate pump group are provided in series on the sewage condensate discharge pipe.

[0014] According to the embodiment of the present application, the temperature of the gas coming out of the gas outlet pipeline is reduced by 4° C., and the air compressor saves 0.8 tons of steam per hour.

[0015] According to an embodiment of the present application, both the cooling water pump and the hot water pump are variable frequency pumps.

[0016] The beneficial effects of the technical solution of the present invention compared with the prior art are:

[0017] 1. Energy saving and consumption saving: After adopting the above structure, the condensate and sewage of the production system of coal-to-methanol, olefins, synthetic ammonia, ethylene glycol, acetic acid, ethanol and other systems enter the lithium bromide refrigeration chiller as a heat source to provide chilled water for the air-cooling tower, realizing the comprehensive utilization of waste heat. Not only a large amount of waste heat is recovered, but also the deep cold water produced can be used for self-consumption. At the same time, the hot water produced also enters the production system for recycling.

[0018] 2. Economical and practical: This application adds a lithium bromide refrigeration chiller, uses the heat of the condensate and wastewater in the production system for exchange refrigeration, and performs secondary cooling on the chilled water entering the air-cooling tower, so that the temperature of the chilled water entering the air-cooling tower is around 12°C (high temperature in summer), which meets the high-load operation of the air separation. As the air temperature at the outlet of the air-cooling tower drops by about 4°C, the air separation steam turbine can reduce steam consumption by 0.8t per hour. At the same time, centralized recovery can effectively reduce the escaped steam by 7.2t / h, and reduce the raw water consumption by 7.2t per hour. The outlet temperature of the air-cooling tower of the air separation unit is reduced, which reduces the system's cooling consumption. The system has sufficient cooling capacity, which can increase higher loads and generate more benefits.

[0019] 3. The present invention can realize unmanned and fully automatic operation in combination with a PLC control system, with a high degree of application integration, a small footprint and low investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure in an example of the present invention.

[0021] The accompanying drawings are as follows:

[0022] 1. Conversion of waste boiler condensate, 2. Conversion of west side condensate, 10. Air cooling tower, 11. Gas outlet pipeline, 12. Cooling water pipeline, 13. Air compressor pipeline, 14. Air cooling tower return pipeline, 15. Tower body, 20. Lithium bromide refrigeration chiller, 21. Connecting pipe, 22. Cooling water inlet pipe, 23. Hot water pipeline, 24. Cooling water supply pipe, 25. Cooling water return pipe, 26. Boiler fixed discharge system, 30. Water cooling tower, 40. Hot water tank, 41. Boiler fixed discharge pipe, 42. Synthetic sewage pipe, 43. Sewage condensate pipe, 121. First valve, 122. Cooling water pump group, 231. Second valve, 232. Hot water pump group, 233. Bypass pipe, 431. Regulating valve group, 432. Condensate pump group. Specific implementation method:

[0023] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0024] In the actual production process of the applicant, in the coal-to-methanol, olefin, synthetic ammonia, ethylene glycol, acetic acid, ethanol and other devices, the temperature of the condensate discharged from the boiler of the conversion device is about 10t / h, the condensate discharged from the boiler of the water vapor area is about 5t / h, the condensate discharged from the synthetic steam drum is about 2t / h, and the steam condensate discharged from the expansion tank of the steam pipe network on the west side of the conversion is about 3t / h. All of them are directly discharged into the ditch and the circulating water pool, which not only wastes most of the sensible heat in the condensate, but also needs to be cooled down by circulating water for further treatment, increasing the load of the circulating water station. At the same time, the outlet air temperature of the air-cooling tower of the air separation unit is higher in summer, approaching the interlocking temperature (16℃), and urgently needs to be cooled down.

[0025] See also Figure 1 As shown, an air-cooling tower refrigeration device for air separation in coal chemical enterprises is shown, including an air-cooling tower 10 and a lithium bromide refrigeration chiller 20 placed in the original production system (coal-to-methanol, olefins, synthetic ammonia, ethylene glycol, acetic acid, ethanol, etc. system). The heat source of the lithium bromide refrigeration chiller 20 comes from the heat of condensate and wastewater in the original production system of the coal chemical enterprise, and the generated chilled water flows into the air-cooling tower 10 for cooling. This application adds a lithium bromide refrigeration chiller 20, uses the heat of condensate and wastewater in the production system for exchange refrigeration, and the air-cooling tower 10 uses chilled water for secondary cooling, so that the outlet air temperature of the air-cooling tower 10 of the air separation device is about 12°C (high temperature in summer), which meets the high-load operation of the air separation. As the outlet air temperature of the air-cooling tower 10 is reduced by about 4°C, the air separation turbine can reduce the steam consumption by 0.8t per hour, and at the same time, the escaped steam can be effectively reduced by 7.2t / h through centralized recovery, reducing the raw water replenishment.

[0026] In this embodiment, the air cooling tower 10 includes a tower body 15, a gas outlet pipeline 11, a cooling water pipeline 12 and an air cooling tower return water pipeline 14; the gas outlet pipeline 11 is provided at the top of the tower body 15, the tower body 15 is provided with a cooling water pipeline 12 and an air compressor pipeline 13, the cooling water pipeline 12 is connected to the water cooling tower 30 through a first valve 121, a cooling water pump group 122 is provided on the pipeline between the first valve 121 and the water cooling tower 30, and the air cooling tower return water pipeline 14 is provided at the bottom of the tower body 15. Among them, at least one valve is provided on the connecting pipe 21.

[0027] Furthermore, the air-cooling tower return water pipeline 14 can lead to the circulating water system of the production systems of coal-to-methanol, olefins, synthetic ammonia, ethylene glycol, acetic acid, ethanol, etc.

[0028] Furthermore, the cooling water pump group 122 and the hot water pump group 232 are both parallel double pumps, each pump group is connected in series with a plurality of valves. The double pumps are designed in parallel and can be used alternately. When one pump fails, it can be shut down for maintenance while the other pump group operates normally to avoid affecting the entire coal-to-methanol system.

[0029] In this embodiment, the heat source inlet of the lithium bromide refrigeration chiller 20 is connected to the hot water tank 40 in the raw coal-to-methanol system through a hot water pipe 23, and a hot water pump group 232 is provided on the hot water pipe 23; the front end of the first valve 121 is provided with a cooling water inlet pipe 22 connected to the cooling water inlet of the lithium bromide refrigeration chiller 20; the rear end of the first valve 121 is provided with a connecting pipe 21 connected to the chilled water outlet of the lithium bromide refrigeration chiller 20; the hot water outlet of the lithium bromide refrigeration chiller 20 is connected to the boiler drain tank; wherein, a second valve 231 is provided on the hot water pipe 23, and the second valve 231 is also connected to a bypass pipe 233, and the bypass pipe 233 leads to the boiler fixed discharge system 26.

[0030] Furthermore, the chilled water is soft water.

[0031] Furthermore, the hot water tank 40 is connected to the boiler fixed discharge pipe 41, the synthetic sewage pipe 42 and the sewage condensate pipe 43 of the coal-to-methanol system, that is, the heat source of the lithium bromide refrigeration chiller 20 is the condensate and sewage of the coal-to-methanol production system. The sewage condensate pipe 43 is provided with a regulating valve group 431 and a condensate pump group 432 in series, and the sewage condensate includes the conversion waste boiler condensate 1 and the conversion west side condensate 2.

[0032] Furthermore, the lithium bromide refrigeration chiller 20 is an intelligent hot water type lithium bromide refrigeration unit with a PLC control box, a liquid crystal display operation panel, and automatic / manual dual-mode.

[0033] Furthermore, the lithium bromide refrigeration chiller 20 includes a generator, a condenser, an absorber, a condenser evaporator and an ORC expander module. The pipe side inlet of the absorber is connected to the cooling water supply pipe 24, and the pipe side outlet of the condenser is connected to the cooling water return pipe 25. The cooling water supply pipe 24 and the cooling water return pipe 25 are connected through a pipeline with a valve.

[0034] The working principle of the lithium bromide refrigeration unit is as follows: the working medium water in the shell side of the condenser evaporator is in a near vacuum state, and its evaporation temperature is about 4°C. It absorbs the heat of the gaseous first working medium in the tube side of the condenser evaporator and becomes gaseous water. The temperature of the gaseous water at this position is about 5°C, and the pressure is about 0.9kpa. The gaseous water is absorbed by the lithium bromide concentrated solution in the absorber, and the lithium bromide concentrated solution becomes a dilute lithium bromide solution. During the process of the lithium bromide concentrated solution absorbing water, the temperature will rise, and too high a temperature will lead to a decrease in the ability to absorb water. In order to ensure that the lithium bromide concentrated solution in the absorber is continuously in the best absorption efficiency, cooling water is introduced into the absorber tube side to keep the temperature of the lithium bromide concentrated solution in the absorber constant at about 40°C; the dilute lithium bromide solution in the absorber is transported to the shell side of the generator, and heat is exchanged from the evaporator After that, the temperature of the waste heat source is about 75℃, and it is connected to the tube side of the generator again. As a result, the dilute lithium bromide solution in the shell side of the generator absorbs the heat of the waste heat source in the tube side, and the water therein evaporates to form gaseous water with a temperature of about 70℃ and a pressure of about 80kpa. The dilute lithium bromide solution becomes a concentrated lithium bromide solution. The concentrated lithium bromide solution in the generator is transported to the absorber and cooled by cooling water, and then continues to absorb the gaseous water transferred from the condenser evaporator. The second condenser tube side is connected with cooling water, and the gaseous water formed in the generator is transported to the shell side of the second condenser. Thus, the gaseous water from the generator is liquefied under the cooling of the cooling water in the second condenser tube side to form liquid water. The liquid water in the condenser is transported to the condenser evaporator to absorb the heat of the first working fluid from the ORC expander, thereby realizing the cycle. According to the test, the gas temperature coming out of the gas outlet pipeline 11 is reduced by 4℃, and the air separation turbine saves 0.8t steam per hour.

[0035] Furthermore, both the cooling water pump and the hot water pump are variable frequency pumps.

[0036] In this embodiment, without changing the original coal-to-methanol process flow, a lithium bromide refrigeration chiller 20 is arranged between the hot water tank 40 and the air-cooling tower 10 and a bypass is arranged to respectively produce steam or hot water and chilled water for use in the circulating water system and air-cooling tower 10 of coal-to-methanol, olefins, synthetic ammonia, ethylene glycol, acetic acid, ethanol and other systems. The chilled water produced by the hot water type lithium bromide refrigeration unit enters the air-cooling tower 10 under the control of a valve to cool the temperature of the compressed air at the lower inlet of the air-cooling tower 10. The cooled compressed air enters the purification system through the gas outlet pipe 11, thereby ensuring the ambient temperature required for the normal operation of the air-cooling tower 10 of the air separation unit.

[0037] In summary, the technical solution of the present application has the following beneficial effects:

[0038] 1. Energy saving and consumption saving: After adopting the above structure, the condensate and sewage of the production system of coal-to-methanol, olefins, synthetic ammonia, ethylene glycol, acetic acid, ethanol and other systems enter the lithium bromide refrigeration chiller as a heat source to provide chilled water for the air-cooling tower, realizing the comprehensive utilization of waste heat. Not only a large amount of waste heat is recovered, but also the deep cold water produced can be used for self-consumption. At the same time, the hot water produced also enters the production system for recycling.

[0039] 2. Economical and practical: This application adds a lithium bromide refrigeration chiller, uses the heat of the condensate and wastewater in the production system for exchange refrigeration, and performs secondary cooling on the chilled water entering the air-cooling tower, so that the temperature of the chilled water entering the air-cooling tower is around 12°C (high temperature in summer), which meets the high-load operation of the air separation. As the air temperature at the outlet of the air-cooling tower drops by about 4°C, the air separation steam turbine can reduce steam consumption by 0.8t per hour. At the same time, centralized recovery can effectively reduce the escaped steam by 7.2t / h, and reduce the raw water consumption by 7.2t per hour. The outlet temperature of the air-cooling tower of the air separation unit is reduced, which reduces the system's cooling consumption. The system has sufficient cooling capacity, which can increase higher loads and generate more benefits.

[0040] 3. The present invention can realize unmanned and fully automatic operation in combination with a PLC control system, with a high degree of application integration, a small footprint and low investment.

[0041] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. An air separation and air cooling tower refrigeration device for coal chemical enterprises, characterized in that: include: An air cooling tower comprises a tower body, a gas outlet pipeline, a cooling water pipeline and an air cooling tower return pipeline; the gas outlet pipeline is arranged on the top of the tower body, a cooling water pipeline and an air compressor pipeline are arranged on the tower body of the tower body, the cooling water pipeline is connected to the water cooling tower through a first valve, a cooling water pump group is arranged on the pipeline between the first valve and the water cooling tower, and the air cooling tower return pipeline is arranged on the bottom of the tower body; The heat source inlet of the lithium bromide refrigeration chiller is connected to the hot water tank in the original production system through a hot water pipe, and a hot water pump group is arranged on the hot water pipe; the front end of the first valve is provided with a cooling water inlet pipe connected to the cooling water inlet of the lithium bromide refrigeration chiller; the rear end of the first valve is provided with a connecting pipe connected to the chilled water outlet of the lithium bromide refrigeration chiller; the hot water outlet of the lithium bromide refrigeration chiller is connected to the boiler drainage pool; Wherein, at least one valve is provided on the connecting pipe, and a second valve is provided on the hot water pipeline.

2. The air separation and air cooling tower refrigeration device for coal chemical enterprises according to claim 1, characterized in that: The lithium bromide refrigeration chiller is an intelligent hot water type lithium bromide refrigeration unit with a PLC control box, a liquid crystal display operation panel, and an automatic / manual dual-mode.

3. The air separation and air cooling tower refrigeration device for coal chemical enterprises according to claim 2, characterized in that: The lithium bromide refrigeration chiller comprises a generator, a condenser, an absorber, a condenser evaporator and an ORC expander module.

4. The air separation and air cooling tower refrigeration device for coal chemical enterprises according to claim 3, characterized in that: The tube side inlet of the absorber is connected to the cooling water supply pipe, and the tube side outlet of the condenser is connected to the cooling water return pipe.

5. The air separation and air cooling tower refrigeration device for coal chemical enterprises according to claim 1, characterized in that: The cooling water pump group and the hot water pump group are both double pumps connected in parallel, and each pump group is connected in series with a plurality of valves.

6. The air separation and air cooling tower refrigeration device for coal chemical enterprises according to claim 1, characterized in that: The chilled water is soft water.

7. The air separation and air cooling tower refrigeration device for coal chemical enterprises according to claim 1, characterized in that: The hot water tank is connected to the boiler fixed discharge pipe, the synthetic sewage discharge pipe and the sewage condensate discharge pipe of the production system.

8. The air separation and air cooling tower refrigeration device for coal chemical enterprises according to claim 5, characterized in that: The sewage condensate discharge pipe is provided with a regulating valve group and a condensate pump group in series.

9. The air separation and air cooling tower refrigeration device for coal chemical enterprises according to claim 1, characterized in that: The temperature of the gas coming out of the gas outlet pipe is reduced by 4° C., and the air compressor saves 0.8 tons of steam per hour.

10. The air separation and air cooling tower refrigeration device for coal chemical enterprises according to claim 1, characterized in that: Both the cooling water pump and the hot water pump are variable frequency pumps.

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