Combined supply device and method for cold and heat comprehensive gradient utilization

Abstract

The invention discloses a combined supply device and method for cold and heat comprehensive gradient utilization, and belongs to the technical field of cold and heat comprehensive utilization and refrigeration of a synthetic ammonia device.The combined supply device comprises a refrigeration system and a cold water circulation system, and the refrigeration system comprises a heating medium supply mechanism, a refrigeration mechanism and a cooling mechanism; the cold water circulation system comprises an ammonia washing tower cooling mechanism, a compressor cooling mechanism and a low methyl liquid nitrogen cooling mechanism, the heating medium supply mechanism is connected with the refrigeration mechanism, and the refrigeration mechanism is connected with the cooling mechanism, the ammonia washing tower cooling mechanism, the compressor cooling mechanism and the low methyl liquid nitrogen cooling mechanism. The ammonia washing tower cooling mechanism is connected with the low methyl liquid nitrogen cooling mechanism, and the low methyl liquid nitrogen cooling mechanism is connected with the compressor cooling mechanism. According to the combined supply device and method for cold and heat comprehensive gradient utilization, the compression efficiency of the synthesis gas compressor is improved, the absorption effect of the low-methyl-liquid nitrogen washing unit and the ammonia washing tower is improved, and the influence of the high temperature of circulating water in summer on the system load is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cold and heat comprehensive utilization and refrigeration technology of synthetic ammonia device, and particularly relates to a cold and heat comprehensive step-by-step utilization combined supply device and method. BACKGROUND

[0002] The heat of many sections of the synthetic ammonia device needs to be removed by a circulating water heat exchanger, and the yield and consumption in summer conditions are often greatly different from those in winter due to the influence of air temperature. The condensate of the urea device and the condensate of the synthetic ammonia device are generally sent to a desalination water device for recovery and treatment after passing through a process condensate heat exchanger, and the ammonia washing tower is washed and cooled by cold boiler water. Since the cold boiler water is cooled by circulating water, the temperature is relatively high, and the flow is relatively small, and the cooling effect of the ammonia washing tower is generally not ideal. In the compression process, in order to improve the operation efficiency of the unit, the circulating cooling water needs to be used to cool the high-temperature gas between stages before entering the next stage of compression. Since the minimum temperature that can be reached by the circulating cooling water is limited by the ambient temperature, the current cooling method is prone to the phenomenon that the outlet gas temperature of the inter-stage cooler is too high, especially in summer, which reduces the efficiency of the compressor and increases energy consumption. At the same time, it also affects the cooling capacity of the next stage of inter-stage cooler. Although the heat exchange area of the inter-stage cooler can be increased to reduce the temperature of the gas entering the next compression stage and improve the compression efficiency, the inter-stage cooling resistance may increase, the pressure difference of the inter-stage cooler increases, the total operation pressure ratio of the system increases, and the energy consumption also increases. The energy consumption required by the resistance may be greater than the energy consumption generated by the cooling, which needs to be considered comprehensively. SUMMARY

[0003] The purpose of the present application is to provide a cold and heat comprehensive step-by-step utilization combined supply device and method. The cold water obtained by the absorption refrigeration mechanism is used to cool the inlet cooling water cooler of the compressor, which improves the compression efficiency of the synthesis gas compressor and reduces the energy consumption of the synthesis gas compressor. The cold water is used to cool the low methyl liquid nitrogen cooler and the cold boiler water cooler, which further improves the absorption effect of the low methyl liquid nitrogen washing unit and the ammonia washing tower, solves the problem of the influence of high temperature of the circulating water on the system load in summer, and realizes the effect of reaching the winter working condition in summer production.

[0004] To achieve the above purpose, the present application provides a cold and heat comprehensive step-by-step utilization combined supply device, which comprises a refrigeration system and a cold water circulation system. The refrigeration system comprises a heat medium supply mechanism, a refrigeration mechanism and a cooling mechanism. The cold water circulation system comprises an ammonia washing tower cooling mechanism, a compressor cooling mechanism and a low methyl liquid nitrogen cooling mechanism. The heat medium supply mechanism is connected with the refrigeration mechanism. The refrigeration mechanism is connected with the cooling mechanism, the ammonia washing tower cooling mechanism, the compressor cooling mechanism and the low methyl liquid nitrogen cooling mechanism respectively. The ammonia washing tower cooling mechanism is connected with the low methyl liquid nitrogen cooling mechanism. The low methyl liquid nitrogen cooling mechanism is connected with the compressor cooling mechanism.

[0005] Preferably, the heat medium supply mechanism comprises a gasification residue water heat medium supply assembly and a condensate heat medium supply assembly, the gasification residue water heat medium supply assembly comprises a gasification residue water unit, a black water heat exchanger and a heat medium water pump, the gasification residue water unit is connected with the black water heat exchanger through a black water pipeline, the heat medium water pump is installed on the heat medium water pipeline connected with the refrigeration mechanism, and the black water heat exchanger is connected with the settling tank;

[0006] The condensate heat medium supply assembly comprises a hot water tank and a condensate pump, the hot water tank is connected with the urea unit and the synthetic ammonia unit, and the condensate pump is installed on a condensate main pipeline connected with the refrigeration mechanism.

[0007] Preferably, the refrigeration mechanism comprises an absorption refrigerating machine, a cold water tank, a cold water pump, a cold water outlet main pipeline and a cold water return main pipeline, the absorption refrigerating machine is connected with the cold water tank through a pipeline, the cold water tank is connected with the cold water outlet main pipeline, the cold water pump is installed on the cold water outlet main pipeline, the cold water outlet main pipeline is connected with a cold water circulation system, the cold water circulation system is connected with the cold water return main pipeline, and the cold water return main pipeline is connected with the absorption refrigerating machine.

[0008] The absorption refrigerating machine comprises an absorber, an evaporator, a condenser, a first generator and a second generator, the absorber is connected with the temperature reduction mechanism, the evaporator is connected with the cold water tank and the cold water return main pipeline respectively, the first generator is connected with the hot water tank and the desalted water unit respectively, and the second generator is connected with the black water heat exchanger in circulation.

[0009] Preferably, the temperature reduction mechanism comprises a cooling tower, a circulating water pump and a circulating pipeline, the water inlet of the cooling tower is connected with the condenser, the water outlet of the cooling tower is connected with the absorber through the circulating pipeline, and the circulating water pump is installed on the circulating pipeline.

[0010] Preferably, the ammonia washing tower cooling mechanism comprises an ammonia washing tower and a cold boiler water cooling device, the cold boiler water cooling device is connected with the ammonia washing tower, and the ammonia washing tower is connected with the low-price liquid nitrogen cooling mechanism.

[0011] Preferably, the compressor cooling mechanism comprises a synthetic gas compressor, an inter-stage circulating water cooler, a compressor inlet cold water cooler and an inter-stage cold water cooler, the synthetic gas compressor comprises a low-pressure cylinder, a turbine, a high-pressure cylinder and a circulating section, the gas inlet of the low-pressure cylinder is connected with the compressor inlet cold water cooler, the gas outlet of the low-pressure cylinder is connected with the inter-stage circulating water cooler, the inter-stage circulating water cooler is connected with the inter-stage cold water cooler, the inter-stage cold water cooler is connected with the high-pressure cylinder, and the high-pressure cylinder is connected with the circulating section.

[0012] Preferably, the low-methyl liquid nitrogen cooling mechanism comprises a low-methyl liquid nitrogen washing unit and a low-methyl inlet cold water cooler, the water inlet of the low-methyl liquid nitrogen washing unit is connected with the low-methyl inlet cold water cooler, and the water outlet of the low-methyl liquid nitrogen washing unit is connected with the compressor inlet cold water cooler.

[0013] Preferably, the chilled water outlet main pipe is connected to the compressor inlet chilled water cooler, the inter-stage chilled water cooler, the boiler water chilled water cooler, and the low-pressure A inlet chilled water cooler, respectively. The output ends of the compressor inlet chilled water cooler, the inter-stage chilled water cooler, the boiler water chilled water cooler, and the low-pressure A inlet chilled water cooler are all connected to the chilled water return main pipe.

[0014] Preferably, the main cold water outlet pipe is also connected to the inter-section cooler of the air separation unit.

[0015] This invention also provides a combined cooling and heating system method, employing the aforementioned combined cooling and heating system device, comprising the following steps:

[0016] Step 1: The black water generated by the gasification slag water unit is sent to the black water heat exchanger through the black water pipeline to heat the heat medium water. The heated heat medium water enters the second generator under the drive of the heat medium water pump, releases heat and flows back to the black water heat exchanger to form a closed loop. The heat-exchanged black water is sent to the settling tank.

[0017] Step 2: The condensate from the urea unit and the process condensate from the ammonia synthesis unit are mixed in a hot water tank. The mixed condensate is then pumped into the first generator and sent to the demineralized water unit for recycling after releasing heat.

[0018] Step 3: The absorption chiller operates using the heat sources from Step 1 and Step 2. The produced low-temperature water is sent to the cold water tank. At the same time, the cooling tower provides circulating cooling water to the absorber and condenser of the absorption chiller through circulating pipelines and circulating water pumps. The heat generated during the operation of the absorption chiller is absorbed by the circulating cooling water and then dissipated in the cooling tower.

[0019] Step 4: When the low-temperature water in the cold water tank is driven by the cold water pump and transported to the cold boiler water cooler through the cold water outlet main pipe, the low-temperature water further cools the cold boiler water that has been initially cooled by the circulating water. The cooled cold boiler water is then sent to the ammonia washing tower to wash and cool the changeover gas. The gas discharged from the ammonia washing tower enters the low-ammonia inlet cold water cooler. After being cooled again by the low-temperature water transported through the cold water outlet main pipe, it is sent to the low-cost liquid nitrogen washing unit.

[0020] Step 5: The syngas discharged from the low-methane liquid nitrogen washing unit first enters the compressor inlet chilled water cooler, where it is cooled by the low-temperature water supplied by the chilled water outlet main pipe. Then it is sent to the low-pressure cylinder of the syngas compressor. The syngas discharged from the low-pressure cylinder is first cooled by the inter-stage circulating water cooler, and then enters the inter-stage chilled water cooler. It is further cooled by the low-temperature water supplied by the chilled water outlet main pipe, and then sent to the high-pressure cylinder. The gas discharged from the high-pressure cylinder enters the circulation section for processing.

[0021] Step Six: The return water from the cold boiler water cooler, the low-pressure inlet cold water cooler, the compressor inlet cold water cooler, and the inter-section cold water cooler is collected in the cold water return main pipe and flows back to the absorption chiller for re-cooling, thus recycling the cold water.

[0022] Therefore, the present invention, employing the above-mentioned combined heat and cold power generation device and method, has the following beneficial effects:

[0023] (1) The combined heat and cold power supply device and method of the present invention delivers the process condensate of the ammonia synthesis unit, the process condensate of the urea unit and the heat medium water of the gasification black water to the absorption chiller. While cooling the hot water, a large amount of cold water is produced by using the waste heat of the hot water. On the one hand, the cold water is used for the compressor inlet cold water cooler and the inter-stage cold water cooler to further reduce the temperature of the compressed gas, improve the efficiency of the syngas compressor and reduce the energy consumption of the syngas compressor. On the other hand, the cold water is used for cooling the cold boiler water of the low-methane liquid nitrogen washing unit and the ammonia washing tower to further improve the absorption effect of the low-methane liquid nitrogen washing unit and the ammonia washing tower. This solves the problem of the impact of high circulating water temperature on the system load in summer and realizes that summer production can reach the winter operating conditions.

[0024] (2) The combined cooling and heating cascade utilization device and method of the present invention, for media with high temperature, firstly selects an inter-section circulating water cooler for initial cooling, and then uses an inter-section cold water cooler for further cooling, reasonably matches the cooling water consumption of the two coolers, reasonably controls the load of the absorption chiller, reduces the circulating water consumption of the absorption chiller, realizes the cascade utilization of energy, and improves the overall energy utilization efficiency.

[0025] (3) The combined heating and cooling system of the present invention is reasonably designed, simple in structure, safe and reliable, and easy to use, and has great value for promotion and application.

[0026] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0027] Figure 1 This is a process flow diagram of an embodiment of a combined heat and cold power supply device and method for integrated cascade utilization of heat and cold power according to the present invention.

[0028] Figure Labels

[0029] 1. Inter-stage circulating water cooler; 2. Syngas compressor; 3. Boiler water cooler; 4. Cooling tower; 5. Cold water return main; 6. Cold water outlet main; 7. Cold water pump; 8. Condensate main; 9. Condensate pump; 10. Black water pipeline; 11. Heat medium water pipeline; 12. Heat medium water pump; 13. Circulating water pump; 14. Circulating pipeline; 15. Absorption chiller; 16. Low-temperature ammonia inlet chiller; 17. Compressor inlet chiller. 18. Water cooler; 19. Inter-stage cold water cooler; 20. Gasification slag water unit; 21. Absorber; 22. Evaporator; 23. Condenser; 24. First generator; 25. Second generator; 26. Cold water tank; 27. Low-methane liquid nitrogen washing unit; 28. Low-pressure cylinder; 29. ​​Steam turbine; 30. High-pressure cylinder; 31. Circulation section; 32. Inter-stage cooler of air separation unit; 33. Ammonia washing tower; 34. Black water heat exchanger; 35. Hot water tank. Detailed Implementation

[0030] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0031] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0032] Example 1

[0033] like Figure 1 As shown, the present invention provides a combined cooling and heating system for integrated cascade utilization, comprising a refrigeration system and a chilled water circulation system. The refrigeration system includes a heat transfer medium supply mechanism, a refrigeration mechanism, and a cooling mechanism. The chilled water circulation system includes an ammonia scrubbing tower cooling mechanism, a compressor cooling mechanism, and a low-methane liquid nitrogen cooling mechanism. The heat transfer medium supply mechanism is connected to the refrigeration mechanism. The refrigeration mechanism is connected to the cooling mechanism, the ammonia scrubbing tower cooling mechanism, the compressor cooling mechanism, and the low-methane liquid nitrogen cooling mechanism, respectively. The ammonia scrubbing tower cooling mechanism is connected to the low-methane liquid nitrogen cooling mechanism, and the low-methane liquid nitrogen cooling mechanism is connected to the compressor cooling mechanism.

[0034] The heat supply mechanism is used to collect the waste heat from the ammonia synthesis unit, urea unit, and gasification slag water unit 19 as the energy input for the refrigeration mechanism; the refrigeration mechanism is used to produce low-temperature water through the absorption chiller 15 and distribute the cold water to each cooling demand point through pipelines and pumps, while simultaneously circulating the cold water to ensure efficient utilization of cold energy; the cooling mechanism is used to cool the refrigeration mechanism, dissipate the waste heat generated during the refrigeration process, and ensure the stable operation of the refrigeration mechanism.

[0035] The ammonia washing tower cooling mechanism is used to solve the problem of insufficient cooling of traditional circulating water by using the cold water provided by the refrigeration unit, thereby improving the washing and cooling effect of the ammonia washing tower 32. The compressor cooling mechanism is used to reduce the inlet and inter-stage gas temperature of the syngas compressor 2 through a stepped mode of preliminary degradation by circulating water and deep cooling by cold water, thereby reducing the energy consumption of the syngas compressor 2 and avoiding the efficiency reduction caused by high circulating water temperature in summer. The low-methyl liquid nitrogen cooling mechanism is used to further cool the gas at the outlet of the ammonia washing tower cooling mechanism and send it to the low-methyl liquid nitrogen washing unit 26. At the same time, the syngas at the outlet of the low-methyl liquid nitrogen washing unit 26 is pretreated and then sent to the syngas compressor 2.

[0036] The heat supply mechanism includes a gasification slag water heat supply component and a condensate heat supply component. The gasification slag water heat supply component includes a gasification slag water unit 19, a black water heat exchanger 33, and a heat medium water pump 12. The gasification slag water unit 19 and the black water heat exchanger 33 are connected through a black water pipeline 10. The heat medium water pump 12 is installed on the heat medium water pipeline 11 that connects the black water heat exchanger 33 to the refrigeration mechanism. The black water heat exchanger 33 is connected to the settling tank.

[0037] The gasification slag water unit 19 generates black water containing waste heat, which serves as the initial heat source for the heat transfer medium. The black water heat exchanger 33 utilizes the waste heat from the gasified black water to heat the heat transfer medium water, achieving heat transfer from the black water to the heat transfer medium water. The heat transfer medium water pump 12 drives the heated heat transfer medium water into the second generator 24 of the absorption chiller 15, and after completing the heat transfer, it flows back to the black water heat exchanger 33, forming a closed-loop cycle. The settling tank receives the cooled black water after heat exchange for further treatment.

[0038] The condensate heat supply assembly includes a hot water tank 34 and a condensate pump 9. The hot water tank 34 is connected to the urea unit and the ammonia synthesis unit. The condensate pump 9 is installed on the condensate main pipe 8 that connects the hot water tank 34 to the refrigeration unit.

[0039] Hot water tank 34 is used to collect process condensate from the urea unit and the ammonia synthesis unit, which is then mixed and output as a unified heat source. Condensate pump 9 is used to pump the mixed condensate from hot water tank 34 into the first generator 23 of the absorption chiller 15, where it is sent to the demineralized water unit after heat exchange. Black water pipeline 10 is used to transport black water.

[0040] The refrigeration system includes an absorption chiller 15, a chilled water tank 25, a chilled water pump 7, a chilled water outlet main pipe 6, and a chilled water return main pipe 5. The absorption chiller 15 is connected to the chilled water tank 25 via pipelines. The chilled water tank 25 is connected to the chilled water outlet main pipe 6, and the chilled water pump 7 is installed on the chilled water outlet main pipe 6. The chilled water outlet main pipe 6 is connected to the chilled water circulation system, the chilled water circulation system is connected to the chilled water return main pipe 5, and the chilled water return main pipe 5 is connected to the absorption chiller 15.

[0041] The chilled water tank 25 stores the low-temperature water produced by the absorption chiller 15, stabilizing the cold source output. The chilled water pump 7 drives the low-temperature water in the chilled water tank 25 to be transported to each cooler through the chilled water outlet main pipe 6. The chilled water outlet main pipe 6 distributes chilled water to the ammonia washing tower 32, the synthesis gas compressor 2, and the low-methane liquid nitrogen washing unit 26. The chilled water return main pipe 5 collects the return water from all coolers and sends it back to the absorption chiller 15 for re-cooling, realizing the recycling of chilled water.

[0042] The absorption chiller 15 includes an absorber 20, an evaporator 21, a condenser 22, a first generator 23, and a second generator 24. The absorber 20 is connected to the cooling mechanism. The evaporator 21 is connected to the cold water tank 25 and the cold water return main pipe 5, respectively. The first generator 23 is connected to the hot water tank 34 and the demineralized water unit, respectively. The second generator 24 is circulatedly connected to the black water heat exchanger 33.

[0043] Absorption chiller 15 drives a refrigeration cycle via first generator 23 and second generator 24, converting waste heat into cold energy to produce low-temperature water. Absorber 20 and condenser 22 work in conjunction with first generator 23 and second generator 24 to complete the refrigeration cycle, requiring heat dissipation through a cooling mechanism. Evaporator 21 generates low-temperature chilled water. First generator 23 receives the mixed condensate from hot water tank 34, absorbs its heat for refrigeration, and the condensate after heat exchange is sent to the demineralized water unit. Second generator 24 receives the heat transfer water heated by black water heat exchanger 33, absorbs its heat for refrigeration, and the heated water returns to black water heat exchanger 33 after heat dissipation.

[0044] The cooling mechanism includes a cooling tower 4, a circulating water pump 13, and a circulating water pipeline 14. The inlet of the cooling tower 4 is connected to the condenser 22, and the outlet of the cooling tower 4 is connected to the absorber 20 through the circulating water pipeline 14. The circulating water pump 13 is installed on the circulating water pipeline 14.

[0045] Cooling tower 4 is used to lower the temperature of the circulating water, providing low-temperature circulating water for absorption chiller 15. Circulating water pump 13 is used to drive the circulating water between cooling tower 4 and absorption chiller 15, ensuring heat dissipation efficiency. Circulating water pipeline 14 is used to connect cooling tower 4 and absorption chiller 15, forming a circulating water transport path.

[0046] The ammonia washing tower cooling mechanism includes an ammonia washing tower 32 and a cold boiler water-cooled water cooler 3. The cold boiler water-cooled water cooler 3 is connected to the ammonia washing tower 32, and the ammonia washing tower 32 is connected to a low-cost liquid nitrogen cooling mechanism.

[0047] The cold boiler water cooler 3 uses the low-temperature water from the cold water outlet main 6 to further cool the cold boiler water that has undergone preliminary cooling by circulating water, thereby improving the washing effect of the ammonia washing tower 32. The ammonia washing tower 32 is used to receive the cooled cold boiler water and to wash and cool the changeover gas.

[0048] The compressor cooling mechanism includes a syngas compressor 2, an inter-stage circulating water cooler 1, a compressor inlet chilled water cooler 17, and an inter-stage chilled water cooler 18. The syngas compressor 2 includes a low-pressure cylinder 27, a steam turbine 28, a high-pressure cylinder 29, and a circulation section 30. The inlet of the low-pressure cylinder 27 is connected to the compressor inlet chilled water cooler 17, and the outlet of the low-pressure cylinder 27 is connected to the inter-stage circulating water cooler 1. The inter-stage circulating water cooler 1 is connected to the inter-stage chilled water cooler 18, the inter-stage chilled water cooler 18 is connected to the high-pressure cylinder 29, and the high-pressure cylinder 29 is connected to the circulation section 30.

[0049] Syngas compressor 2 is used to compress syngas through low-pressure cylinder 27 and high-pressure cylinder 29, providing high-pressure syngas for subsequent processes. Low-pressure cylinder 27 performs initial compression of the syngas, while high-pressure cylinder 29 further compresses it and improves efficiency by cooling the inlet gas temperature. Circulation section 30 circulates a portion of the syngas exiting high-pressure cylinder 29, regulating system pressure and flow. Inter-section circulating water cooler 1 provides initial cooling of the syngas exiting low-pressure cylinder 27, and compressor inlet chilled water cooler 17 uses chilled water to cool the syngas entering low-pressure cylinder 27, reducing compression power. Inter-section chilled water cooler 18 further cools the initially cooled syngas, preventing insufficient cooling of the circulating water in summer.

[0050] The low-methanol liquid nitrogen cooling mechanism includes a low-methanol liquid nitrogen washing unit 26 and a low-methanol inlet chilled water cooler 16. The inlet of the low-methanol liquid nitrogen washing unit 26 is connected to the low-methanol inlet chilled water cooler 16, and the outlet of the low-methanol liquid nitrogen washing unit 26 is connected to the compressor inlet chilled water cooler 17.

[0051] The low-methane liquid nitrogen washing unit 26 is used to purify and separate the gas at the outlet of the ammonia washing tower 32, providing qualified raw material gas for the syngas compressor 2. The low-methane inlet chilled water cooler 16 is used to cool the gas at the outlet of the ammonia washing tower 32 with chilled water, so that it meets the process requirements of the low-methane liquid nitrogen washing unit 26.

[0052] The chilled water outlet main pipe is connected to the compressor inlet chilled water cooler 17, the inter-stage chilled water cooler 18, the chilled boiler water cooler 3, and the low-pressure A inlet chilled water cooler 16, respectively. The output ends of the compressor inlet chilled water cooler 17, the inter-stage chilled water cooler 18, the chilled boiler water cooler 3, and the low-pressure A inlet chilled water cooler 16 are all connected to the chilled water return main pipe 5.

[0053] The chilled water outlet main pipe 6 is also connected to the inter-stage cooler 31 of the air separation unit or a cooler such as a carbon dioxide compressor. The inter-stage cooler 31 of the air separation unit is used to receive chilled water from the chilled water outlet main pipe 6, cool the inter-stage gas of the air separation unit, and expand the application range of chilled water.

[0054] The gasification slag water unit, urea unit, synthetic ammonia unit, demineralized water unit, and low-methyl liquid nitrogen washing unit are all set up using existing technologies, so they are not described in detail.

[0055] This invention also provides a combined cooling and heating system method, employing the aforementioned combined cooling and heating system device, comprising the following steps:

[0056] Step 1: The black water generated by the gasification slag water unit 19 is sent to the black water heat exchanger 33 through the black water pipeline 10 to heat the heat medium water. The heated heat medium water enters the second generator 24 under the drive of the heat medium water pump 12, releases heat and flows back to the black water heat exchanger 33 to form a closed loop. The heat-exchanged black water is sent to the settling tank.

[0057] Step 2: The condensate from the urea unit and the process condensate from the ammonia synthesis unit are mixed in the hot water tank 34. The mixed condensate is driven by the condensate pump 9 and enters the first generator 23. After releasing heat, the condensate is sent to the demineralized water unit for recycling.

[0058] The heat medium water of the gasification black water heat exchanger 33 serves as a separate heat source for the second generator 24 of the absorption chiller 15, forming a closed loop. The process condensate from the ammonia synthesis unit and the condensate from the urea unit are combined and then enter the first generator 23. In this way, the impact on the absorption chiller 15 will be greatly reduced if the flow of the two condensates fluctuates or if the urea unit stops.

[0059] Step 3: The absorption chiller 15 operates using the heat sources from Step 1 and Step 2. The produced low-temperature water is sent to the cold water tank 25. At the same time, the cooling tower 4 provides circulating cooling water to the absorber 20 and condenser 22 of the absorption chiller 15 through the circulating water pipeline 14 and the circulating water pump 13. The heat generated by the absorption chiller 15 during operation is absorbed by the circulating cooling water and then dissipated in the cooling tower 4.

[0060] Step 4: When the low-temperature water in the cold water tank 25 is driven by the cold water pump 7 and transported to the cold boiler water cooler 3 through the cold water outlet main pipe 6, the low-temperature water further cools the cold boiler water that has been initially cooled by the circulating water. The cooled cold boiler water is then sent to the ammonia washing tower 32 to wash and cool the changeover gas. The gas discharged from the ammonia washing tower 32 enters the low-ammonia inlet cold water cooler 16. After being cooled again by the low-temperature water transported through the cold water outlet main pipe 6, it is sent to the low-cost liquid nitrogen washing unit.

[0061] Step 5: The syngas discharged from the low-methane liquid nitrogen washing unit 26 first enters the compressor inlet chilled water cooler, where it is cooled by the low-temperature water supplied by the chilled water outlet main pipe 6. Then it is sent to the low-pressure cylinder 27 of the syngas compressor 2. The syngas discharged from the low-pressure cylinder 27 is first cooled by the inter-stage circulating water cooler 1, and then enters the inter-stage chilled water cooler 18. It is further cooled by the low-temperature water supplied by the chilled water outlet main pipe 6, and then sent to the high-pressure cylinder 29. The gas discharged from the high-pressure cylinder 29 enters the circulation section 30 for processing.

[0062] Step 6: The return water from the cold boiler water cooler 3, the low-temperature inlet cold water cooler 16, the compressor inlet cold water cooler 17, and the inter-section cold water cooler 18 flows into the cold water return main pipe 5 and returns to the absorption chiller 15 for re-cooling and recycling of cold water.

[0063] Summer operating conditions: Due to the high ambient temperature, the cooling effect of circulating water is limited. The amount of cold water used in each cold water cooler is increased to enhance the cooling of media such as boiler water and syngas in the ammonia washing tower 32, so as to ensure that the operating efficiency of the unit is close to that of winter operating conditions.

[0064] Winter operating conditions: Due to the good cooling effect of circulating water, some cold water coolers can be reduced or even stopped according to the production process requirements; at the same time, some of the heat source (such as some condensate or heat transfer water) originally supplied to the absorption chiller 15 can be used for other purposes such as heating.

[0065] Therefore, the present invention adopts the above-mentioned combined cooling and heating cascade utilization device and method. By using the cold water taken by the absorption refrigeration mechanism to cool the compressor inlet cold water cooler, the compression efficiency of the syngas compressor is improved and the energy consumption of the syngas compressor is reduced. By using the cold water to cool the low-methane inlet cold water cooler and the cold boiler water cooler, the absorption effect of the low-methane liquid nitrogen washing unit and the ammonia washing tower is further improved. This solves the problem of the impact of high circulating water temperature on the system load in summer and achieves the effect of summer production reaching winter operating conditions.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A combined heat and cold power supply device for integrated cascade utilization, characterized in that: It includes a refrigeration system and a chilled water circulation system. The refrigeration system includes a heat transfer medium supply mechanism, a refrigeration mechanism, and a cooling mechanism. The chilled water circulation system includes an ammonia washing tower cooling mechanism, a compressor cooling mechanism, and a low-methane liquid nitrogen cooling mechanism. The heat transfer medium supply mechanism is connected to the refrigeration mechanism. The refrigeration mechanism is connected to the cooling mechanism, the ammonia washing tower cooling mechanism, the compressor cooling mechanism, and the low-methane liquid nitrogen cooling mechanism, respectively. The ammonia washing tower cooling mechanism is connected to the low-methane liquid nitrogen cooling mechanism, and the low-methane liquid nitrogen cooling mechanism is connected to the compressor cooling mechanism.

2. The combined heat and cold power supply device for integrated cascade utilization of heat and cold as described in claim 1, characterized in that: The heat supply system includes a gasification slag water heat supply component and a condensate heat supply component. The gasification slag water heat supply component includes a gasification slag water unit, a black water heat exchanger, and a heat medium water pump. The gasification slag water unit and the black water heat exchanger are connected through a black water pipeline. A heat medium water pump is installed on the heat medium water pipeline connecting the black water heat exchanger and the refrigeration unit. The black water heat exchanger is connected to the settling tank. The condensate heat supply assembly includes a hot water tank and a condensate pump. The hot water tank is connected to the urea unit and the ammonia synthesis unit. The condensate pump is installed on the condensate main pipe connecting the hot water tank to the refrigeration unit.

3. A combined heat and cold power supply device for integrated cascade utilization of heat and cold as described in claim 1, characterized in that: The refrigeration system includes an absorption chiller, a chilled water tank, a chilled water pump, a chilled water outlet main pipe, and a chilled water return main pipe. The absorption chiller is connected to the chilled water tank via pipelines. The chilled water tank is connected to the chilled water outlet main pipe, and a chilled water pump is installed on the chilled water outlet main pipe. The chilled water outlet main pipe is connected to the chilled water circulation system, the chilled water circulation system is connected to the chilled water return main pipe, and the chilled water return main pipe is connected to the absorption chiller. The absorption chiller includes an absorber, an evaporator, a condenser, a first generator, and a second generator. The absorber is connected to the cooling mechanism. The evaporator is connected to the cold water tank and the cold water return main pipe. The first generator is connected to the hot water tank and the demineralized water unit. The second generator is circulatedly connected to the black water heat exchanger.

4. A combined heat and cold power supply device for integrated cascade utilization of heat and cold as described in claim 1, characterized in that: The cooling system includes a cooling tower, a circulating water pump, and a circulating pipeline. The inlet of the cooling tower is connected to the condenser, and the outlet of the cooling tower is connected to the absorber through the circulating pipeline. A circulating water pump is installed on the circulating pipeline.

5. A combined heat and cold power supply device for integrated cascade utilization of heat and cold as described in claim 3, characterized in that: The ammonia washing tower cooling system includes an ammonia washing tower and a cold boiler water-cooled water cooler. The cold boiler water-cooled water cooler is connected to the ammonia washing tower, and the ammonia washing tower is connected to a low-cost liquid nitrogen cooling system.

6. A combined heat and cold power supply device for integrated cascade utilization of heat and cold as described in claim 5, characterized in that: The compressor cooling system includes a syngas compressor, an inter-stage circulating water cooler, a compressor inlet chilled water cooler, and an inter-stage chilled water cooler. The syngas compressor includes a low-pressure cylinder, a turbine, a high-pressure cylinder, and a circulating section. The inlet of the low-pressure cylinder is connected to the compressor inlet chilled water cooler, the outlet of the low-pressure cylinder is connected to the inter-stage circulating water cooler, the inter-stage circulating water cooler is connected to the inter-stage chilled water cooler, the inter-stage chilled water cooler is connected to the high-pressure cylinder, and the high-pressure cylinder is connected to the circulating section.

7. A combined heat and cold power supply device for integrated cascade utilization of heat and cold as described in claim 6, characterized in that: The low-methyl liquid nitrogen cooling mechanism includes a low-methyl liquid nitrogen washing unit and a low-methyl inlet chilled water cooler. The inlet of the low-methyl liquid nitrogen washing unit is connected to the low-methyl inlet chilled water cooler, and the outlet of the low-methyl liquid nitrogen washing unit is connected to the compressor inlet chilled water cooler.

8. A combined heat and cold power supply device for integrated cascade utilization of heat and cold as described in claim 7, characterized in that: The chilled water outlet main pipe is connected to the compressor inlet chilled water cooler, the inter-stage chilled water cooler, the boiler water chilled water cooler, and the low-pressure A inlet chilled water cooler, respectively. The output ends of the compressor inlet chilled water cooler, the inter-stage chilled water cooler, the boiler water chilled water cooler, and the low-pressure A inlet chilled water cooler are all connected to the chilled water return main pipe.

9. A combined heat and cold power supply device for integrated cascade utilization of heat and cold as described in claim 3, characterized in that: The main cold water outlet pipe is also connected to the inter-section cooler of the air separation unit.

10. A combined heat and cold power (CHP) method for integrated cascade utilization of heating and cooling, characterized in that: The combined heat and cold power supply device according to any one of claims 1-9 includes the following steps: Step 1: The black water generated by the gasification slag water unit is sent to the black water heat exchanger through the black water pipeline to heat the heat medium water. The heated heat medium water enters the second generator under the drive of the heat medium water pump, releases heat and flows back to the black water heat exchanger to form a closed loop. The heat-exchanged black water is sent to the settling tank. Step 2: The condensate from the urea unit and the process condensate from the ammonia synthesis unit are mixed in a hot water tank. The mixed condensate is then pumped into the first generator and sent to the demineralized water unit for recycling after releasing heat. Step 3: The absorption chiller operates using the heat sources from Step 1 and Step 2. The produced low-temperature water is sent to the cold water tank. At the same time, the cooling tower provides circulating cooling water to the absorber and condenser of the absorption chiller through circulating pipelines and circulating water pumps. The heat generated during the operation of the absorption chiller is absorbed by the circulating cooling water and then dissipated in the cooling tower. Step 4: When the low-temperature water in the cold water tank is driven by the cold water pump and transported to the cold boiler water cooler through the cold water outlet main pipe, the low-temperature water further cools the cold boiler water that has been initially cooled by the circulating water. The cooled cold boiler water is then sent to the ammonia washing tower to wash and cool the changeover gas. The gas discharged from the ammonia washing tower enters the low-ammonia inlet cold water cooler. After being cooled again by the low-temperature water transported through the cold water outlet main pipe, it is sent to the low-cost liquid nitrogen washing unit. Step 5: The syngas discharged from the low-methane liquid nitrogen washing unit first enters the compressor inlet chilled water cooler, where it is cooled by the low-temperature water supplied by the chilled water outlet main pipe. Then it is sent to the low-pressure cylinder of the syngas compressor. The syngas discharged from the low-pressure cylinder is first cooled by the inter-stage circulating water cooler, and then enters the inter-stage chilled water cooler. It is further cooled by the low-temperature water supplied by the chilled water outlet main pipe, and then sent to the high-pressure cylinder. The gas discharged from the high-pressure cylinder enters the circulation section for processing. Step Six: The return water from the cold boiler water cooler, the low-pressure inlet cold water cooler, the compressor inlet cold water cooler, and the inter-section cold water cooler is collected in the cold water return main pipe and flows back to the absorption chiller for re-cooling, thus recycling the cold water.

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