Cooperative production device and control method for recycling ammonia gas

Abstract

The invention discloses a collaborative production device for recycling gas ammonia and a control method, and belongs to the technical field of synthetic ammonia production devices and ammonia water preparation, and the device comprises an ammonia water preparation device, a gas ammonia delivery system and an ice maker recycling system. Through pipeline connection, gas ammonia of a synthesis ammonia cooler and a liquid ammonia filling station is respectively led to a high-efficiency ammonia absorber, an absorption tower and an ice maker three-section inlet separator. The absorption tower adopts two-stage absorption to produce dilute ammonia water; the efficient ammonia absorber generates stronger ammonia water through reaction of process water and gas ammonia. The ice maker system compresses, cools and delivers part of gas ammonia, and a delivery gas source can be flexibly selected or blended between high-temperature gas ammonia at an outlet of four sections of the ice maker and normal-temperature gas ammonia at an outlet of an inter-section cooler according to seasons. And when the ammonia water preparation is stopped, all ammonia gas is cut to the ice maker to be recycled. According to the invention, total recovery and zero emission of ammonia gas are realized, the operation mode can be intelligently adjusted according to working conditions, and the energy utilization efficiency and the operation flexibility are improved while environmental protection is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of synthetic ammonia production equipment and ammonia water preparation technology, and in particular to a co-production equipment and control method for recovering and utilizing gaseous ammonia. Background Technology

[0002] During the ammonia synthesis plant's production process, seasonal variations significantly impact equipment operating loads, with the refrigeration unit load increasing substantially in summer compared to winter. Specifically, the gaseous phases from the primary, secondary, and tertiary ammonia refrigeration units in the synthesis section are connected to different sections of the refrigeration unit, leading to varying degrees of load increases in each section. This issue directly restricts the ammonia synthesis plant's production capacity during the summer, thereby reducing the company's economic benefits.

[0003] In the ammonia preparation process, existing equipment mostly uses liquid ammonia to produce ammonia water. Although the vaporization process of liquid ammonia can have a certain cooling effect on ammonia preparation, this method directly consumes liquid ammonia product, making it uneconomical. In addition, the gas phase at the top of the concentrated ammonia tank and the dilute ammonia tank, after being washed and recovered by demineralized water, is usually vented on-site or sent to a flare for venting. This emission behavior does not meet environmental protection requirements and is likely to cause environmental impact.

[0004] During the loading operation at liquid ammonia filling stations, the gaseous ammonia generated inside the tanks is recovered and sent to the refrigeration system of the ammonia synthesis unit. When the number of filling vehicles is large, the amount of gaseous ammonia returning to the refrigeration system increases accordingly, and this amount fluctuates significantly with the number of filling vehicles. This phenomenon not only further increases the operating load on the refrigeration system, but also, due to the complex and variable composition of the gas inside the filling vehicles (containing nitrogen, hydrogen, and gaseous ammonia, etc.), it easily leads to an increase in the venting volume of the refrigeration system, resulting in a waste of gaseous ammonia resources.

[0005] For non-synthetic ammonia enterprises within chemical industrial parks that use gaseous ammonia, the common method of obtaining gaseous ammonia is to transport liquid ammonia by vehicle or pipeline, and then heat and vaporize the liquid ammonia before use. This method increases the cost of liquid ammonia transportation and vaporization, significantly impacting the enterprise's profitability. Summary of the Invention

[0006] The purpose of this invention is to provide a collaborative production device and control method for recovering and utilizing ammonia gas to solve the above-mentioned problems.

[0007] This invention provides a co-production device for recovering and utilizing ammonia gas, including an ammonia water preparation device, a gaseous ammonia delivery system, and an ice machine recovery system; The ammonia preparation device includes an absorption tower, a high-efficiency ammonia absorber, a 20% ammonia tank, and connecting pipelines. The ammonia delivery system includes an ammonia delivery pipeline, an ammonia delivery pressure reducing valve, and a normal temperature low-pressure ammonia pipeline. The ice machine recycling system includes an ice machine, a three-stage inlet separator, an inter-stage cooler, and a terminal cooler; The ammonia outlet of the synthetic ammonia cooler is divided into a first branch and a second branch. The first branch is connected to the inlet of the three-stage inlet separator of the ice machine, and the second branch is connected to the ammonia inlet of the high-efficiency ammonia absorber via an ammonia regulating valve and an ammonia flow meter. The gas phase outlet of the liquid ammonia filling station is divided into a third branch and a fourth branch. The third branch is connected to the ice machine, and the fourth branch is connected to the gas ammonia inlet of the absorption tower.

[0008] Preferably, the absorption tower is internally divided into upper and lower sections. The lower section is equipped with a water tank for self-circulation of dilute ammonia water, and the upper section is equipped with a demineralized water inlet. The top of the absorption tower is equipped with a non-condensable gas outlet connected to the fuel gas pipeline network. The dilute ammonia water outlet of the lower water tank of the absorption tower is connected to the inlet of the dilute ammonia water cooler through a dilute ammonia water circulation pump. A dilute ammonia water density meter is installed on the outlet pipe of the dilute ammonia water circulation pump.

[0009] Preferably, the outlet pipeline of the dilute ammonia water cooler is divided into a fifth branch and a sixth branch. The fifth branch returns to the middle of the absorption tower, and the sixth branch is connected to the process water pipeline. The process water pipeline is equipped with a process water regulating valve and a process water flow meter, and its outlet is connected to the process water inlet of the high-efficiency ammonia absorber.

[0010] Preferably, the high-efficiency ammonia absorber is equipped with an ammonia absorption chamber and an ammonia water outlet pipe. A concentrated ammonia water density meter is installed on the ammonia water outlet pipe of the high-efficiency ammonia absorber, and the ammonia water coming out of the high-efficiency ammonia absorber flows by gravity into a 20% ammonia water tank.

[0011] Preferably, the 20% ammonia water tank is connected to an ammonia water pump. One ammonia water pump circulates back to the 20% ammonia water tank via an ammonia water return pipeline, another pump sends the ammonia water back to the process water pipeline of the high-efficiency ammonia absorber, and the third pump sends the ammonia water to the external gas delivery pipeline.

[0012] Preferably, the outlet of the three-stage inlet separator of the ice machine is connected to the ice machine after merging with the air from the second stage of the ice machine; the outlet of the third stage of the ice machine is connected to the inlet of the inter-stage cooler; the outlet pipeline of the inter-stage cooler is divided into a seventh branch and an eighth branch, the seventh branch is connected to the inlet of the fourth stage of the ice machine, and the eighth branch is connected to the external ammonia pipeline through the ambient temperature low-pressure ammonia pipeline.

[0013] Preferably, the four-section outlet pipeline of the ice machine is divided into a ninth branch and a tenth branch. The ninth branch is connected to the inlet of the terminal cooler, and the tenth branch is connected to the external ammonia pipeline through the external ammonia pressure reducing valve. The outlet of the terminal cooler is sequentially connected to a condenser and the ice machine trough. The non-condensable gas outlet of the ice machine trough is connected to the fuel gas network through a tail gas recovery device.

[0014] A control method is provided for a co-production device for recovering and utilizing ammonia gas as described above, comprising: When the ammonia preparation device is operating normally, the gas phase of the liquid ammonia filling station is sent to the absorption tower for absorption; The concentration of dilute ammonia is calculated based on the measurement value of the dilute ammonia density meter. When the concentration reaches the set value, a portion of the dilute ammonia is sent to the process water pipeline. Based on the comparison between the measured concentration of concentrated ammonia water density meter and the target set value, adjust the process water regulating valve to control the flow rate of process water entering the high-efficiency ammonia absorber. When the ammonia concentration in the 20% ammonia tank is too low, a portion of the ammonia is returned to the process water pipeline by the ammonia pump and sent to the high-efficiency ammonia absorber for circulation and concentration.

[0015] Preferably, when the ammonia preparation device is shut down, all the gas phase of the liquid ammonia filling station is sent to the ice machine system for recovery, and all the gaseous ammonia generated by the synthetic ammonia cooler is sent to the three-stage inlet separator of the ice machine, while increasing the operating load of the ice machine.

[0016] Preferably, in winter, the gaseous ammonia from the fourth stage outlet of the ice machine is mainly sent out after being depressurized by the external gaseous ammonia pressure reducing valve; in summer, depending on user needs, the gaseous ammonia from the inter-stage cooler outlet can be sent out, or it can be mixed with the depressurized gaseous ammonia from the fourth stage outlet of the ice machine before being sent out.

[0017] Therefore, the present invention, employing the aforementioned synergistic production device and control method for ammonia recovery and utilization, has the following beneficial effects: (1) The co-production device and control method for recovering and utilizing ammonia gas of the present invention reduces the amount of ammonia gas in the de-icing machine by directly recovering ammonia gas from the ammonia cooler, thereby reducing the load on the ice machine. On the one hand, it can reduce the steam consumption of the ice machine turbine under the same conditions, and at the same time, it can meet the demand for increased production in summer. On the other hand, the ammonia water preparation device directly uses ammonia gas, reducing the liquid ammonia vaporization process.

[0018] (2) The co-production device and control method for the recovery and utilization of ammonia gas of the present invention, in addition to being recovered by the de-icing machine system, the gas phase of the liquid ammonia filling station is normally absorbed by the absorption tower of the ammonia water preparation device. The absorption tower adopts pressurized absorption. The non-condensable gas of the absorption tower is incorporated into the fuel gas pipeline network and sent to the boiler for combustion to recover heat. After flue gas desulfurization, it is released into the atmosphere, which is environmentally friendly and economical.

[0019] (3) The collaborative production device and control method for ammonia recovery and utilization of the present invention mixes ambient low-pressure ammonia and high-temperature high-pressure ammonia in different proportions, and adjusts the appropriate ammonia pressure and temperature. On the one hand, it ensures that the ammonia does not liquefy during the ammonia transportation process, and realizes safe long-distance ammonia transportation. On the other hand, it meets the needs of ammonia users, reduces the process of ammonia users using liquid ammonia vaporization, and creates conditions for the collaborative development of the park.

[0020] The co-production device and control method for ammonia recovery and utilization of the present invention are reasonably designed, simple in structure, safe and reliable, and easy to use, and have great value for promotion and application.

[0021] 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

[0022] Figure 1 This is a schematic diagram of an embodiment of a collaborative production device and control method for recovering and utilizing ammonia gas according to the present invention.

[0023] Reference numerals in the attached diagram: 1. External ammonia pressure reducing valve; 2. Terminal cooler; 3. Ambient temperature low-pressure ammonia pipeline; 4. Inter-stage cooler; 5. Inlet separator; 6. Ammonia water return pipeline; 7. Ammonia water pump; 8. Ammonia cooler; 9. Ammonia gas regulating valve; 10. Ammonia gas flow meter; 11. Concentrated ammonia water density meter; 12. Process water flow meter; 13. Process water regulating valve; 14. Dilute ammonia water regulating valve; 15. Absorption tower; 16. Dilute ammonia water cooler; 17. Dilute ammonia water density meter; 18. Circulation pump; 19. High-efficiency ammonia absorber; 20. 20% ammonia water tank; 21. Ice machine; 22. Condenser; 23. Small tank of ice machine; 24. Tail gas recovery device. Detailed Implementation

[0024] To better understand the above technical solutions, a detailed description of the solutions will be provided below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0025] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0026] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0027] This invention provides a co-production device for recovering and utilizing ammonia gas, including an ammonia water preparation device, a gaseous ammonia delivery system, and an ice machine 21 recovery system; The ammonia preparation device includes an absorption tower 15, a high-efficiency ammonia absorber 19, a 20% ammonia tank 20, and connecting pipelines. The ammonia delivery system includes an ammonia delivery pipeline, an ammonia delivery pressure reducing valve 1, and a normal temperature low-pressure ammonia delivery pipeline 3. The ice machine 21 recovery system includes an ice machine 21, an ice machine three-stage inlet separator 5, an inter-stage cooler 4, and a terminal cooler 2; The ammonia outlet of the synthetic ammonia cooler 8 is divided into a first branch and a second branch. The first branch is connected to the inlet of the three-stage inlet separator 5 of the ice machine, and the second branch is connected to the ammonia inlet of the high-efficiency ammonia absorber 19 via the ammonia regulating valve 9 and the ammonia flow meter 10. The gas phase outlet of the liquid ammonia filling station is divided into a third branch and a fourth branch. The third branch is connected to the ice machine 21, and the fourth branch is connected to the gas ammonia inlet of the absorption tower 15.

[0028] The absorption tower 15 is internally divided into upper and lower sections. The lower section is equipped with a water tank for self-circulation of dilute ammonia water, and the upper section is equipped with a demineralized water inlet. The top of the absorption tower 15 is equipped with a non-condensable gas outlet connected to the fuel gas pipeline network. The dilute ammonia water outlet of the lower water tank of the absorption tower 15 is connected to the inlet of the dilute ammonia water cooler 16 through a dilute ammonia water circulation pump 18. A dilute ammonia water density meter 17 is installed on the outlet pipe of the dilute ammonia water circulation pump 18.

[0029] The outlet pipeline of the dilute ammonia water cooler 16 is divided into a fifth branch and a sixth branch. The fifth branch returns to the middle of the absorption tower 15, and the sixth branch is connected to the process water pipeline. The process water pipeline is equipped with a process water regulating valve 13 and a process water flow meter 12, and its outlet is connected to the process water inlet of the high-efficiency ammonia absorber 19.

[0030] The high-efficiency ammonia absorber 19 is equipped with an ammonia absorption chamber and an ammonia water outlet pipe. A concentrated ammonia water density meter 11 is installed on the ammonia water outlet pipe of the high-efficiency ammonia absorber 19. The ammonia water coming out of the high-efficiency ammonia absorber 19 flows by gravity into the 20% ammonia water tank 20.

[0031] The 20% ammonia water tank 20 is connected to an ammonia water pump 7. One ammonia water pump 7 circulates back to the 20% ammonia water tank 20 through the ammonia water return pipeline 6, another pump sends it back to the process water pipeline of the high-efficiency ammonia absorber 19, and the third pump sends it to the external ammonia gas pipeline.

[0032] The outlet of the three-stage inlet separator 5 of the ice machine merges with the air from the second stage of the ice machine and is connected to the ice machine 21; the outlet of the third stage of the ice machine is connected to the inlet of the inter-stage cooler 4; the outlet pipeline of the inter-stage cooler 4 is divided into a seventh branch and an eighth branch, the seventh branch is connected to the inlet of the fourth stage of the ice machine, and the eighth branch is connected to the external ammonia pipeline through the ambient temperature low-pressure ammonia pipeline 3.

[0033] The four-section outlet pipeline of the ice machine is divided into a ninth branch and a tenth branch. The ninth branch is connected to the inlet of the terminal cooler 2, and the tenth branch is connected to the external ammonia pipeline through the external ammonia pressure reducing valve 1. The outlet of the terminal cooler 2 is connected in sequence to the condenser 22 and the ice machine trough 23. The non-condensable gas outlet of the ice machine trough is connected to the fuel gas pipeline network through the tail gas recovery device 24.

[0034] A control method is provided for a co-production device for recovering and utilizing ammonia gas as described above, comprising: When the ammonia preparation device is operating normally, the gas phase of the liquid ammonia filling station is sent to the absorption tower 15 for absorption. The concentration of dilute ammonia is calculated based on the measurement value of dilute ammonia density meter 17. When the concentration reaches the set value, a portion of the dilute ammonia is sent to the process water pipeline. Based on the comparison between the measured concentration of concentrated ammonia water density meter 11 and the target set value, adjust the process water regulating valve 13 to control the flow rate of process water entering the high-efficiency ammonia absorber 19. When the ammonia concentration in the 20% ammonia tank 20 is too low, part of the ammonia is returned to the process water pipeline by the ammonia pump 7 and sent to the high-efficiency ammonia absorber 19 for circulation and concentration.

[0035] When the ammonia preparation device is shut down, all the gas phase of the liquid ammonia filling station is sent to the ice machine system for recovery, and all the gaseous ammonia produced by the synthetic ammonia cooler 8 is sent to the three-stage inlet separator 5 of the ice machine, while increasing the operating load of the ice machine 21.

[0036] In winter, the gaseous ammonia from the fourth section outlet of the ice machine is mainly depressurized and then sent out through the external ammonia pressure reducing valve 1; in summer, depending on user needs, the gaseous ammonia from the fourth section outlet of the intercooler can be sent out, or it can be mixed with the depressurized gaseous ammonia from the fourth section outlet of the ice machine before being sent out.

[0037] The workflow of this collaborative production unit is as follows: Workflow under normal operating conditions (ammonia preparation unit in operation): In this mode, the core of the system is to recover gaseous ammonia and prepare ammonia water with controllable concentration, while maintaining the balanced operation of the ice machine system. The generated gaseous ammonia is divided into two paths. One path enters the three-stage inlet separator 5 of the ice machine recovery system as supplementary air intake for the ice machine 21 system; the other path is accurately metered through the gaseous ammonia regulating valve 9 and the gaseous ammonia flow meter 10 and then sent to the high-efficiency ammonia absorber 19 of the ammonia water preparation device. The volatile gas phase is also divided into two paths. One path enters the ice machine system for recovery; the other path is led to the absorption tower 15 of the ammonia water preparation device for absorption treatment.

[0038] Ammonia preparation and concentration control: a. Initial absorption in absorber 15: Gaseous ammonia from the liquid ammonia filling station enters absorber 15. The tower employs a two-stage absorption process: the upper stage uses demineralized water for initial absorption, while the lower stage utilizes dilute ammonia water from the bottom tank for circulating absorption. The absorbed non-condensable gas is discharged from the top of the tower to the fuel gas pipeline network.

[0039] b. Dilute ammonia water circulation and output: The dilute ammonia water at the bottom of the tower is sent out by the dilute ammonia water circulation pump 18. After being cooled by the dilute ammonia water cooler 16, part of it is returned to the middle of the absorption tower 15 to continue to participate in the absorption cycle; the other part (when the concentration indicated by the dilute ammonia water density meter 17 reaches the standard) is transported to the process water pipeline.

[0040] c. High-efficiency ammonia absorption and concentration: Demineralized water or dilute ammonia water from the process water pipeline comes into full contact with gaseous ammonia from the synthetic ammonia cooler 8 in the ammonia absorption chamber of the high-efficiency ammonia absorber 19, generating ammonia water and releasing heat of solution (carried away by circulating cooling water). The generated concentrated ammonia water is detected by the concentrated ammonia water density meter 11 and then flows by gravity into the 20% ammonia water tank 20.

[0041] d. Concentration Closed-Loop Regulation: The system automatically adjusts the process water regulating valve 13 on the process water pipeline by comparing the measured value of the concentrated ammonia water density meter 11 with the target set value, thereby changing the absorbent flow rate entering the high-efficiency ammonia absorber 19 and stabilizing the production of ammonia water of the required concentration. If the ammonia water concentration in the 20% ammonia water tank 20 is too low, the ammonia water pump 7 can be started to pump some of the ammonia water in the tank back to the process water pipeline and return to the high-efficiency ammonia absorber 19 for re-absorption and concentration, forming an internal circulation until the concentration is qualified.

[0042] e. Product output: Ammonia water with qualified concentration is pumped through ammonia water pump 7, and a portion of it can be sent to user units for use.

[0043] Ice Machine 21 System Collaborative Operation Process: The third-stage inlet separator 5 of the ice machine collects part of the gaseous ammonia from the synthetic ammonia cooler 8 and the gas from the second stage of the ice machine. After mixing, it enters the third stage of the ice machine for compression. The compressed gaseous ammonia is cooled by the interstage cooler 4, resulting in two streams: one stream enters the fourth stage of the ice machine for further pressurization; the other stream is kept as "normal temperature low-pressure gaseous ammonia" for backup. The high-temperature and high-pressure gaseous ammonia at the outlet of the fourth stage of the ice machine is also divided into two paths: one path is cooled by the terminal cooler 2, then liquefied by the condenser 22 and enters the ice machine tank 23, where its non-condensable gas is finally sent to the fuel gas pipeline; the other path is kept as "high-temperature and high-pressure gaseous ammonia" for external supply.

[0044] Workflow under abnormal or maintenance conditions (ammonia preparation unit shutdown): When the ammonia preparation unit needs to be shut down, the system switches to full recovery mode to ensure no ammonia gaseous emissions. All gaseous phase from the liquid ammonia filling station is switched to the pipeline leading to the ice machine 21. Simultaneously, all ammonia gaseous output from the synthetic ammonia cooler 8 is also directed to the three-stage inlet separator 5 of the ice machine. Due to the increased intake volume, the operating load of the ice machine 21 needs to be increased accordingly to process all recovered ammonia gaseous output and compress and condense it into liquid ammonia for storage.

[0045] Flexible adjustment process for ammonia delivery: The system can flexibly select the source and parameters of delivered ammonia based on external user needs and seasonal characteristics. In winter mode, when the outside temperature is low, the high-temperature, high-pressure ammonia from the fourth stage outlet of the ice machine is reduced to the user's required pressure via the delivery ammonia pressure reducing valve 1 and then delivered through the delivery ammonia pipeline. This method utilizes the heat of the ammonia itself to reduce potential condensation problems at the user end. In summer mode, when the outside temperature is high, the system provides two options to meet user process requirements and reduce the load on the ice machine 21: It can use all or part of the ambient temperature, low-pressure ammonia from the inter-stage cooler 4 outlet, directly delivering it through the ambient temperature, low-pressure ammonia pipeline 3. Alternatively, the above-mentioned ambient temperature, low-pressure ammonia can be blended with the reduced-pressure high-temperature, high-pressure ammonia to obtain ammonia supplied to the user at a suitable temperature and pressure.

[0046] It is evident that this collaborative production unit, through pipeline design and intelligent control, achieves 100% recovery of ammonia from multiple sources under different operating conditions (either for the preparation of ammonia water or for liquefaction back to the ice machine 21), and can flexibly adjust the quality of the delivered ammonia according to the season and demand, thus achieving a balance between safety, environmental protection and energy efficiency.

[0047] Therefore, this invention employs the aforementioned collaborative production device and control method for ammonia recovery and utilization, achieving full recovery and zero emissions of ammonia, resulting in significant environmental benefits. The device constructs multiple, complementary recovery pathways, ensuring that ammonia from all sources (synthetic ammonia coolers, liquid ammonia filling stations) can be effectively processed without direct venting. The ammonia is either absorbed to produce valuable commercial ammonia water or returned to the refrigeration system for reliquefaction and recovery. The remaining trace amounts of non-condensable gas are also introduced into the fuel gas pipeline for combustion, thus achieving near-zero ammonia emissions during the production process and solving the environmental pollution problems of traditional processes.

[0048] To improve energy efficiency and reduce system operating energy consumption, a control method can be used to dynamically allocate the destination of gaseous ammonia based on the operating status of the ammonia preparation unit, avoiding long-term high-load operation of the ice machine and saving electricity. In winter, high-temperature gaseous ammonia from the fourth stage of the ice machine is directly supplied, utilizing its own thermal energy to reduce reheat energy consumption at the user end; in summer, low-pressure gaseous ammonia at room temperature after the inter-stage cooler is prioritized for supply, or blended, effectively reducing the final cooling load and compression power consumption of the ice machine system, thereby improving the overall energy efficiency of the system. Non-condensable gas from the absorption tower and non-condensable gas from the ice machine's small tank are both sent to the fuel gas pipeline network to recover their calorific value.

[0049] The system achieves automated and high-precision control of ammonia concentration by forming a closed-loop control circuit using a dilute ammonia density meter, a concentrated ammonia density meter, process water / ammonia gas regulating valves, and a DCS system. The system can monitor and adjust the flow rate of process water (dilute ammonia or demineralized water) entering the high-efficiency ammonia absorber in real time, and automatically correct product concentration deviations through an ammonia reflux concentration mechanism. This ensures stable production of high-quality ammonia that meets the set target concentration (e.g., 20%), improving product consistency and commercial value, and reducing human intervention and quality fluctuations.

[0050] The system enhances operational flexibility and process adaptability, simultaneously handling gaseous ammonia from both the synthetic ammonia cooler and the liquid ammonia filling station, which may differ in pressure and purity, thus improving the unit's adaptability to complex production conditions. The unit features a coordinated operation mode for ammonia water preparation and ice machine operation, as well as an emergency / maintenance mode for pure ice machine recovery, allowing for flexible switching based on production needs and ensuring the continuity and stability of the upstream main unit (synthetic ammonia). It can flexibly output ammonia water products of different concentrations and gaseous ammonia products of different pressures and temperatures to meet the diverse needs of downstream users, based on market demand. Improved system reliability and production safety are achieved by effectively recovering and converting gaseous ammonia into stable ammonia water or liquid ammonia, fundamentally reducing the safety risks caused by gaseous ammonia accumulation in the plant area. The various systems (ammonia water preparation, ice machine recovery, and gaseous ammonia delivery) are interconnected and have redundant paths (e.g., gaseous ammonia can go to either the ice machine or ammonia water production). In the event of a temporary failure in one unit, the control strategy can be adjusted to ensure a safe destination for the gaseous ammonia, enhancing the reliability and resilience of the entire production system.

[0051] Integrated and intensive design saves investment and land area by integrating previously scattered ammonia preparation facilities, ammonia recovery facilities, ice machine systems, and external delivery facilities into a single integrated design. Through ingenious pipeline connections and a shared control system, equipment and functions are streamlined. This reduces redundant equipment, lowers overall investment costs, saves factory space, and makes the production layout more compact and efficient.

[0052] 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 co-production device for recovering and utilizing ammonia gas, characterized in that, This includes an ammonia preparation unit, a gaseous ammonia delivery system, and an ice machine recovery system; The ammonia preparation device includes an absorption tower (15), a high-efficiency ammonia absorber (19), a 20% ammonia tank (20), and connecting pipelines; The ammonia delivery system includes an ammonia delivery pipeline, an ammonia delivery pressure reducing valve (1), and a normal temperature low-pressure ammonia delivery pipeline (3). The ice machine recycling system includes an ice machine (21), an ice machine three-stage inlet separator (5), an inter-stage cooler (4), and a terminal cooler (2). The ammonia outlet of the synthetic ammonia cooler (8) is divided into a first branch and a second branch. The first branch is connected to the inlet of the three-stage inlet separator (5) of the ice machine, and the second branch is connected to the ammonia inlet of the high-efficiency ammonia absorber (19) via the ammonia regulating valve (9) and the ammonia flow meter (10). The gas phase outlet of the liquid ammonia filling station is divided into a third branch and a fourth branch. The third branch is connected to the ice machine (21), and the fourth branch is connected to the gas ammonia inlet of the absorption tower (15).

2. The co-production device for recovering and utilizing ammonia gas according to claim 1, characterized in that, The absorption tower (15) is internally divided into upper and lower sections. The lower section is equipped with a water tank for self-circulation of dilute ammonia water, and the upper section is equipped with a demineralized water inlet. The top of the absorption tower (15) is equipped with a non-condensable gas outlet connected to the fuel gas pipeline network. The dilute ammonia water outlet of the lower water tank of the absorption tower (15) is connected to the inlet of the dilute ammonia water cooler (16) through a dilute ammonia water circulation pump (18). A dilute ammonia water density meter (17) is installed on the outlet pipe of the dilute ammonia water circulation pump (18).

3. The co-production device for recovering and utilizing ammonia gas according to claim 2, characterized in that, The outlet pipeline of the dilute ammonia water cooler (16) is divided into a fifth branch and a sixth branch. The fifth branch returns to the middle of the absorption tower (15), and the sixth branch is connected to the process water pipeline. The process water pipeline is equipped with a process water regulating valve (13) and a process water flow meter (12), and its outlet is connected to the process water inlet of the high-efficiency ammonia absorber (19).

4. The co-production device for recovering and utilizing ammonia gas according to claim 3, characterized in that, The high-efficiency ammonia absorber (19) is equipped with an ammonia absorption chamber and an ammonia water outlet pipe. There is a concentrated ammonia water density meter (11) on the ammonia water outlet pipe of the high-efficiency ammonia absorber (19). The ammonia water coming out of the high-efficiency ammonia absorber (19) flows into the 20% ammonia water tank (20) by gravity.

5. The co-production device for recovering and utilizing ammonia gas according to claim 4, characterized in that, The 20% ammonia water tank (20) is connected to an ammonia water pump (7). One ammonia water pump (7) circulates back to the 20% ammonia water tank (20) through the ammonia water return pipeline (6), another sends it back to the process water pipeline of the high-efficiency ammonia absorber (19), and the third sends it to the external gas ammonia pipeline.

6. The co-production device for recovering and utilizing ammonia gas according to claim 1, characterized in that, The outlet of the three-stage inlet separator (5) of the ice machine is connected to the ice machine (21) after merging with the air from the second stage of the ice machine; the outlet of the third stage of the ice machine (21) is connected to the inlet of the inter-stage cooler (4); the outlet pipeline of the inter-stage cooler (4) is divided into a seventh branch and an eighth branch, the seventh branch is connected to the fourth stage inlet of the ice machine (21), and the eighth branch is connected to the external ammonia pipeline through the ambient temperature low-pressure ammonia pipeline (3).

7. The co-production device for recovering and utilizing ammonia gas according to claim 6, characterized in that, The four-section outlet pipeline of the ice machine (21) is divided into a ninth branch and a tenth branch. The ninth branch is connected to the inlet of the terminal cooler (2), and the tenth branch is connected to the external ammonia pipeline through the external ammonia pressure reducing valve (1). The outlet of the terminal cooler (2) is connected in sequence to the condenser (22) and the ice machine trough (23). The non-condensable gas outlet of the ice machine trough (23) is connected to the fuel gas pipeline through the tail gas recovery device (24).

8. A control method for a co-production device for recovering and utilizing ammonia gas as described in any one of claims 1-7, characterized in that, include: When the ammonia preparation device is operating normally, the gas phase of the liquid ammonia filling station is sent to the absorption tower (15) for absorption; The concentration of dilute ammonia is calculated based on the measurement value of the dilute ammonia density meter (17). When the concentration reaches the set value, a portion of the dilute ammonia is sent to the process water pipeline. Based on the comparison between the measured concentration of concentrated ammonia water density meter (11) and the target set value, adjust the process water regulating valve (13) to control the flow rate of process water entering the high-efficiency ammonia absorber (19); When the ammonia concentration in the 20% ammonia tank (20) is too low, a portion of the ammonia is returned to the process water pipeline by the ammonia pump (7) and sent to the high-efficiency ammonia absorber (19) for circulation and concentration.

9. The control method for a co-production device for recovering and utilizing ammonia gas according to claim 8, characterized in that, When the ammonia preparation device is shut down, all the gas phase of the liquid ammonia filling station is sent to the ice machine system for recovery, and all the gaseous ammonia generated by the synthetic ammonia cooler (8) is sent to the three-stage inlet separator (5) of the ice machine, while increasing the operating load of the ice machine.

10. The control method for a co-production device for recovering and utilizing ammonia gas according to claim 8, characterized in that, In winter, the gaseous ammonia from the fourth section outlet of the ice machine is mainly depressurized by the external gaseous ammonia pressure reducing valve (1) and then sent out. In summer, depending on the user's needs, the gaseous ammonia from the outlet of the inter-stage cooler (4) can be sent out, or it can be mixed with the depressurized gaseous ammonia from the fourth section outlet of the ice machine and then sent out.

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