A comprehensive utilization device of synthetic ammonia fuel gas

Abstract

The utility model discloses a kind of comprehensive utilization device of synthetic ammonia fuel gas, liquid nitrogen washing purification device is connected with sulfur recovery combustion furnace, vent flare and phosphorus ammonium hot blast furnace pipeline in parallel respectively;The liquid nitrogen washing purification device is connected with phosphorus ammonium hot blast furnace pipeline through closed sampler, second flowmeter and self-control valve group.The utility model realizes the resource utilization of synthetic ammonia fuel gas, reduces the burden to environment and the cost of phosphorus ammonium production.

Description

Technical Field

[0001] This utility model belongs to the field of tail gas resource utilization technology, specifically relating to a comprehensive utilization device for synthetic ammonia fuel gas. Background Technology

[0002] Ammonia synthesis fuel gas is a necessary emission in the ammonia synthesis process, containing hydrogen, nitrogen, ammonia, methane, carbon monoxide, etc. Currently, this fuel gas is typically sent directly to a flare for combustion, resulting in resource waste and significant pollution. The resource utilization of ammonia synthesis fuel gas currently involves two main steps: ammonia recovery and hydrogen recovery. Hydrogen recovery is the most economically efficient step, generally employing a liquid nitrogen scrubbing process to separate hydrogen from the carbon monoxide-containing tail gas, followed by hydrogen recovery. The carbon monoxide-containing tail gas is then directly vented and burned, which still results in significant resource waste and exacerbates the greenhouse effect. Therefore, it is necessary to recycle and utilize the tail gas after hydrogen recovery from ammonia synthesis fuel gas.

[0003] Chinese patent CN102502492A discloses a method for recovering vent gas from synthetic ammonia production. The method involves mixing the gas remaining after separating ammonia and hydrogen from the vent gas with the steam entering a coal gasifier as a mixed gasifying agent. The molar percentage of the mixed gasifying agent is 1-20% for the gas remaining after separating ammonia and hydrogen from the vent gas, and 80-99% for the steam. No dedicated catalytic conversion device is required. At a high temperature of 1000-1500℃ in the coal gasifier, the conversion rate of methane to carbon monoxide and hydrogen reaches 60-99%. This invention recycles the waste gas from the production process as a raw material, turning waste into treasure and reducing the consumption of raw coal by 3-5%.

[0004] Chinese patent CN119976883A discloses a comprehensive ammonia synthesis gas recovery and utilization system, comprising: an ammonia synthesis feedstock system for providing hydrogen and nitrogen feedstocks to an ammonia synthesis production system; an ammonia synthesis production system for producing liquid ammonia and generating cooling capacity based on the hydrogen and nitrogen feedstocks; an ammonia synthesis carbon emission reduction system for producing liquid carbon dioxide using the tail gas from the ammonia synthesis feedstock system and the cooling capacity provided by the ammonia synthesis production system, while simultaneously providing hydrogen-rich feedstock gas and methane-rich gas to the ammonia synthesis feedstock system; and an ammonia synthesis tail gas recovery system for producing helium using the tail gas from the ammonia synthesis production system as feedstock, while simultaneously providing hydrogen and nitrogen feedstocks to the ammonia synthesis production system and providing methane-rich gas to the ammonia synthesis feedstock system, and utilizing the cooling capacity provided by the ammonia synthesis production system to improve adsorption efficiency. This invention solves the problems of low-value utilization, low economic efficiency, high carbon emissions, helium waste, and high energy consumption in existing ammonia synthesis processes.

[0005] However, current methods for recovering and utilizing synthetic ammonia fuel gas primarily focus on treating gases containing ammonia and hydrogen. The environmental impact of the tail gas after hydrogen and ammonia recovery remains a significant challenge, and effective solutions for its recycling and resource utilization are yet to be found. Given the substantial production volume of synthetic ammonia fuel gas, the amount of tail gas remaining after ammonia and hydrogen recovery is still enormous. Therefore, in-depth and comprehensive recovery and utilization of this tail gas is a crucial step in further improving the recovery and utilization of synthetic ammonia fuel gas. Summary of the Invention

[0006] To address the aforementioned technical problems, this utility model provides a comprehensive utilization device for synthetic ammonia fuel gas, which realizes the resource utilization of synthetic ammonia fuel gas, reduces the burden on the environment, and lowers the cost of phosphate production.

[0007] To achieve the above objectives, this utility model provides a comprehensive utilization device for synthetic ammonia fuel gas, wherein a liquid nitrogen washing and purification device is connected in parallel with a sulfur recovery combustion furnace, a venting flare, and a phosphate hot air furnace pipeline; the liquid nitrogen washing and purification device is connected to the phosphate hot air furnace pipeline via a sealed sampler, a second flow meter, and a self-control valve group.

[0008] Preferably, the pipeline connecting the liquid nitrogen washing and purification device to the sulfur recovery combustion furnace is equipped with a first flow meter and a frequency conversion control valve, which are respectively connected to the DCS control system; the pipeline connecting the liquid nitrogen washing and purification device to the venting flare is equipped with a venting shut-off valve; the venting shut-off valve is connected to the DCS control system.

[0009] Preferably, the sealed sampler includes an injection valve, a pressure reducing valve, and a sampling valve connected in sequence.

[0010] More preferably, the pressure reducing valve is connected to the circulation valve and the return valve in sequence via pipelines, and finally connected to the automatic control valve group via pipelines; the pressure reducing valve is connected to the venting flare pipeline via the venting valve.

[0011] Preferably, a pipeline check valve, a pipeline shut-off valve, and a pipeline boundary valve are sequentially installed on the pipeline connecting the second flow meter and the automatic control valve group.

[0012] In a further preferred embodiment, a low-pressure nitrogen storage tank is provided in the middle of the pipeline connecting the second flow meter and the pipeline check valve, and the low-pressure nitrogen storage tank is connected to the fuel gas transportation pipeline via a nitrogen shut-off valve; the second flow meter is connected to the venting flare via a recovery gas valve.

[0013] Preferably, the self-regulating valve group consists of a self-adjusting pre-valve, a self-adjusting valve, and a self-adjusting post-valve connected in series; a fuel gas storage tank is provided on the pipeline connecting the self-regulating valve group to the ammonium phosphate hot blast furnace, and the fuel gas storage tank is connected to the ammonium phosphate hot blast furnace pipeline via a fuel gas control valve.

[0014] More preferably, the self-regulating valve is connected to the DCS control system.

[0015] More preferably, the self-regulating valve includes a regulating valve body, with an intelligent positioner and an air pipe on the top of the regulating valve body. The air pipe is connected to a pneumatic diaphragm actuator, and the pneumatic diaphragm actuator has an exhaust port on its top.

[0016] Preferably, the liquid nitrogen washing and purification device is connected to the DCS control system, and the DCS control system is connected to the pipeline check valve.

[0017] The beneficial effects of this utility model are as follows: by setting up a sulfur recovery combustion furnace, a venting flare and a phosphate hot air furnace in parallel, the exhaust gas containing carbon monoxide after liquid nitrogen washing and purification is comprehensively treated, effectively utilizing the heat energy in the exhaust gas, avoiding the waste of resources and environmental burden caused by direct emission, and saving natural gas consumption, thus achieving waste utilization and cost savings. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0019] Figure 2 This is a schematic diagram of the self-regulating valve.

[0020] In the diagram, 1 is the liquid nitrogen washing and purification device, 2 is the sulfur recovery combustion furnace, 3 is the venting flare, 4 is the DCS control system, 5 is the fuel gas storage tank, 6 is the phosphate hot air furnace, 7 is the low-pressure nitrogen storage tank, 8 is the first flow meter, 9 is the frequency converter control valve, 10 is the vent shut-off valve, 11 is the sampling valve, 12 is the pressure reducing valve, 13 is the vent valve, 14 is the circulation valve, 15 is the return sampling valve, 16 is the sampling valve, 17 is the second flow meter, 18 is the nitrogen shut-off valve, 19 is the pipeline check valve, 20 is the pipeline shut-off valve, 21 is the recovery gas valve, 22 is the pipeline boundary valve, 23 is the pre-self-adjusting valve, 24 is the self-adjusting valve, 25 is the post-self-adjusting valve, 26 is the fuel gas control valve, 27 is the exhaust port, 28 is the pneumatic diaphragm actuator, 29 is the gas pipe, 30 is the intelligent positioner, and 31 is the regulating valve body. Detailed Implementation The technical solution of this utility model will be further explained below with reference to the accompanying drawings and specific embodiments. It is worth noting that the following embodiments are only preferred embodiments of this utility model and should not be construed as limiting this utility model. The protection scope of this utility model should be determined by the content of the claims. Modifications or substitutions made by those skilled in the art to the technical solution of this utility model without creative effort all fall within the protection scope of this utility model.

[0021] Example 1 A comprehensive utilization device for synthetic ammonia fuel gas includes a liquid nitrogen washing and purification device 1 connected in parallel with a sulfur recovery combustion furnace 2, a venting flare 3, and a phosphate hot air furnace 6. This device allows the residual carbon monoxide-containing tail gas after treatment by the liquid nitrogen washing and purification device 1 to be fed into the sulfur recovery combustion furnace 2 and the phosphate hot air furnace 6 for heat energy recovery and utilization. Excess tail gas, or when the sulfur recovery combustion furnace 2 and the phosphate hot air furnace 6 are shut down, is burned by the venting flare 3. The liquid nitrogen washing and purification device 1 is connected to the phosphate hot air furnace 6 pipeline via a sealed sampler, a second flow meter 17, and a self-control valve group. This allows for sampling and analysis of the residual carbon monoxide-containing tail gas after treatment by the liquid nitrogen washing and purification device 1, flow monitoring, and regulation of the tail gas entering the phosphate hot air furnace 6.

[0022] Preferably, a first flow meter 8 and a frequency converter 9 are installed on the pipeline connecting the liquid nitrogen washing and purification device 1 and the sulfur recovery combustion furnace 2. The first flow meter 8 and the frequency converter 9 are respectively connected to the DCS control system 4. The amount of exhaust gas treated by the liquid nitrogen washing and purification device 1 entering the sulfur recovery combustion furnace 2 is controlled by the first flow meter 8 and the frequency converter 9. Under normal circumstances, 0-10% of the total exhaust gas is controlled to enter the sulfur recovery combustion furnace 2. When the phosphate hot air furnace 6 is shut down or the demand for exhaust gas decreases, the opening of the frequency converter 9 is adjusted. The volume of exhaust gas entering the sulfur recovery combustion furnace 2 is increased; the pipeline connecting the liquid nitrogen washing and purification device 1 and the venting flare 3 is equipped with a venting shut-off valve 10 to control whether the exhaust gas enters the venting flare 3 for combustion and venting; the venting shut-off valve 10 is connected to the DCS control system 4. Under normal circumstances, the venting shut-off valve 10 is in the closed state. When the sulfur recovery combustion furnace 9 is shut down or the amount of exhaust gas entering the sulfur recovery combustion furnace 9 exceeds the set processing capacity, the venting shut-off valve 10 is opened so that the excess exhaust gas enters the venting flare 3 for combustion and venting.

[0023] Preferably, the sealed sampler includes an inlet valve 11, a pressure reducing valve 12, and a sampling valve 16 connected in sequence to reduce the pressure and sample the exhaust gas in the pipeline.

[0024] Preferably, the pressure reducing valve 12 is connected to the circulation valve 14 and the return sampling valve 15 via pipelines, so that the unsampled exhaust gas is returned to the exhaust gas transport pipeline, which facilitates the next step of recycling and treatment, avoids resource waste and environmental pollution, and finally connects to the automatic control valve group via pipelines to enter the phosphate hot air furnace 6 for recycling and treatment; the pressure reducing valve 12 is connected to the venting flare 3 pipeline via the venting valve 13, so that the excess exhaust gas can be transported to the venting flare 3 for combustion treatment, avoiding the exhaust gas remaining in the valve group or pipeline, which would cause safety risks.

[0025] Preferably, a pipeline check valve 19, a pipeline shut-off valve 20, and a pipeline boundary valve 22 are sequentially installed in the middle of the pipeline connecting the second flow meter 17 and the automatic control valve group to prevent backflow of tail gas and affect the aforementioned device.

[0026] In a further preferred embodiment, a low-pressure nitrogen storage tank 7 is provided in the middle of the pipeline connecting the second flow meter 17 and the pipeline check valve 19. The low-pressure nitrogen storage tank 7 is connected to the fuel gas transportation pipeline via a nitrogen shut-off valve 18, which can be used to purge the pipeline with low-pressure nitrogen to avoid safety risks such as pressure buildup caused by residual exhaust gas in the pipeline. The second flow meter 17 is connected to the venting flare 3 via a recovery gas valve 21 to transport the residual exhaust gas in the pipeline to the venting flare 3 for combustion and utilization, thereby avoiding safety risks caused by residual exhaust gas in the pipeline or affecting the operation stability of the phosphate hot blast furnace 6 when starting up the next unit.

[0027] Preferably, the self-regulating valve group consists of a self-regulating pre-valve 23, a self-regulating valve 24, and a self-regulating post-valve 25 connected in series, used to regulate the amount of exhaust gas entering the phosphate hot blast furnace 6; a fuel gas storage tank 5 is provided on the pipeline connecting the self-regulating valve group to the phosphate hot blast furnace 6, and the fuel gas storage tank 5 is connected to the pipeline of the phosphate hot blast furnace 6 via a fuel gas control valve 26 to replenish the remaining fuel gas in the phosphate hot blast furnace 6, wherein the pressure level of the replenished fuel gas is 0.4 MPa.

[0028] In a further preferred embodiment, the self-regulating valve 24 is connected to the DCS control system 4 and is used to control the opening degree of the self-regulating valve 24, etc. When the liquid nitrogen washing and purification device 1 stops, the signal is transmitted to the DCS control system 4, which then controls the self-regulating valve 24 to cut off the gas flow, thereby preventing irrelevant exhaust gas from entering the ammonium phosphate hot air furnace 6 and preventing gas backflow in the ammonium phosphate hot air furnace 6.

[0029] More preferably, the self-regulating valve 24 includes a regulating valve body 31, with an intelligent positioner 30 and an air pipe 29 on the top of the regulating valve body 31. The air pipe 29 is connected to a pneumatic diaphragm actuator 28, and the top of the pneumatic diaphragm actuator 28 is provided with an exhaust port 27. This ensures that the exhaust gas can smoothly enter the ammonium phosphate hot air furnace 6, and also prevents the gas in the ammonium phosphate hot air furnace 6 from backflowing and causing safety hazards.

[0030] Preferably, the liquid nitrogen washing and purification device 1 is connected to the DCS control system 4 to receive start and stop signals from the liquid nitrogen washing and purification device 1; the DCS control system 4 is connected to the pipeline check valve 19 to control the transportation of exhaust gas.

[0031] Example 2 The minimum calorific value of the carbon monoxide-containing exhaust gas treated by the liquid nitrogen washing and purification device 1 is 1130 kcal / Nm3, and the minimum flow rate is 2000 Nm3 / h. Therefore, it can provide at least 2.26 million kcal / h of heat. The phosphate hot air furnace requires about 8 million kcal / h of heat to provide a heat source for drying the product in the dryer. Therefore, this application can save 2.26 million kcal / h of heat. With the calorific value of natural gas being 8500 kcal / Nm3, this utility model can save 266 Nm3 / h of natural gas.

Claims

1. A comprehensive utilization device for synthetic ammonia fuel gas, characterized in that: The liquid nitrogen washing and purification device (1) is connected in parallel with the sulfur recovery combustion furnace (2), the venting torch (3) and the ammonium phosphate hot air furnace (6) pipelines respectively; the liquid nitrogen washing and purification device (1) is connected to the ammonium phosphate hot air furnace (6) pipeline via a sealed sampler, a second flow meter (17) and an automatic control valve group.

2. The comprehensive utilization device for synthetic ammonia fuel gas according to claim 1, characterized in that: The pipeline connecting the liquid nitrogen washing and purification device (1) to the sulfur recovery combustion furnace (2) is equipped with a first flow meter (8) and a frequency conversion control valve (9), which are respectively connected to the DCS control system (4); the pipeline connecting the liquid nitrogen washing and purification device (1) to the venting torch (3) is equipped with a venting stop valve (10); the venting stop valve (10) is connected to the DCS control system (4).

3. The comprehensive utilization device for synthetic ammonia fuel gas according to claim 1, characterized in that: The sealed sampler includes an injection valve (11), a pressure reducing valve (12), and a sampling valve (16) connected in sequence.

4. The comprehensive utilization device for synthetic ammonia fuel gas according to claim 3, characterized in that: The pressure reducing valve (12) is connected to the circulation valve (14) and the return valve (15) in sequence via pipelines, and finally connected to the automatic control valve group via pipelines; the pressure reducing valve (12) is connected to the venting torch (3) pipeline via the venting valve (13).

5. The comprehensive utilization device for synthetic ammonia fuel gas according to claim 1, characterized in that: The pipeline connecting the second flow meter (17) to the automatic control valve group is provided with a pipeline check valve (19), a pipeline shut-off valve (20), and a pipeline boundary valve (22) in sequence.

6. The comprehensive utilization device for synthetic ammonia fuel gas according to claim 5, characterized in that: The pipeline connecting the second flow meter (17) and the pipeline check valve (19) is provided with a low-pressure nitrogen storage tank (7), which is connected to the fuel gas transportation pipeline via a nitrogen shut-off valve (18); the second flow meter (17) is connected to the venting flare (3) via a recovery gas valve (21).

7. A comprehensive utilization device for synthetic ammonia fuel gas according to claim 1 or 5, characterized in that: The self-regulating valve group consists of a self-regulating front valve (23), a self-regulating valve (24), and a self-regulating rear valve (25) connected in series; a fuel gas storage tank (5) is provided on the pipeline connecting the self-regulating valve group to the ammonium phosphate hot air furnace (6), and the fuel gas storage tank (5) is connected to the pipeline of the ammonium phosphate hot air furnace (6) via a fuel gas control valve (26).

8. A comprehensive utilization device for synthetic ammonia fuel gas according to claim 7, characterized in that: The self-regulating valve (24) is connected to the DCS control system (4).

9. A comprehensive utilization device for synthetic ammonia fuel gas according to claim 7, characterized in that: The self-regulating valve (24) includes a regulating valve body (31), the top of which is provided with an intelligent positioner (30) and an air pipe (29). The air pipe (29) is connected to a pneumatic diaphragm actuator (28), and the top of the pneumatic diaphragm actuator (28) is provided with an exhaust port (27).

10. A comprehensive utilization device for synthetic ammonia fuel gas according to claim 1, characterized in that: The liquid nitrogen washing and purification device (1) is connected to the DCS control system (4), and the DCS control system is connected to the pipeline check valve (19).

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