Sulfur-tolerant shift anti-corrosion process for synthesis ammonia

Abstract

The invention relates to the technical field of production of synthetic ammonia from coal, and discloses a sulfur-tolerant shift anti-corrosion process for synthetic ammonia. In order to solve the technical problems that stainless steel equipment and pipelines are corroded due to the fact that transformed gas condensate is enriched with an acid medium and corrosion prevention and energy efficiency improvement are difficult to consider at the same time in the existing sulfur-tolerant shift section of the synthetic ammonia prepared from the coal, the process innovatively integrates a closed-loop process of gas-liquid pretreatment, two-stage shift reaction, gradient heat recovery, ammonia washing and impurity removal and pH real-time monitoring; on the basis of removing NHH in front of an ammonia washing tower to reduce enrichment of an acidic medium, the pH value of the process condensate is monitored in real time by combining an online pH analyzer, and acidification of the condensate is inhibited from the source; and meanwhile, the design of multi-stage heat exchange and energy recovery is optimized, and the collaborative goal of corrosion prevention, high heat recovery efficiency and low circulating water consumption is achieved. The method is simple in process flow and stable in operation, can be widely applied to industrial production of synthetic ammonia prepared from coal, and has extremely high industrial application value.

Description

Technical Field

[0001] This invention belongs to the field of coal-to-ammonia production technology, specifically relating to a sulfur-resistant shift gas anti-corrosion process for ammonia synthesis, which is particularly suitable for the shift gas treatment process containing acidic media under high pressure conditions. Background Technology

[0002] In coal-to-ammonia production, the sulfur-resistant shift conversion section is a crucial step in converting CO in water gas into H2, directly impacting the quality of feed gas and production efficiency in subsequent ammonia synthesis processes. Water gas contains a large amount of CO2, small amounts of H2S, COS, NH3, and saturated water vapor. After the shift reaction, more CO2 is generated, while unreacted acidic media (H2S, COS), NH3, and saturated water vapor remain. To recover the heat of the reaction and separate the condensate, the shift gas needs to undergo multiple heat exchange cooling processes. During this process, NH3, due to its high solubility, separates with the condensate, while the acidic media gradually accumulates and ionizes at low temperatures.

[0003] H⁺ and S²⁻ increase the acidity of the condensate, causing continuous corrosion to stainless steel equipment and pipelines under high pressure, severely shortening equipment lifespan, and increasing maintenance costs and safety risks.

[0004] Existing technologies for addressing this corrosion problem have significant limitations: First, while using corrosion-resistant materials or periodically replacing equipment can alleviate corrosion, it significantly increases initial investment and operating costs. Second, adding corrosion inhibitors to neutralize acidic media can easily introduce impurities that affect catalyst activity, and requires continuous addition of reagents, increasing the operational burden. Third, some processes employ end-of-pipe pH monitoring and alkali neutralization, which only provides reactive treatment after corrosion occurs and cannot inhibit the accumulation of acidic media at the source; furthermore, neutralization products may cause pipeline blockage. Simultaneously, existing technologies often focus on a single corrosion prevention objective, neglecting the optimization of heat recovery efficiency and circulating water consumption in the conversion process. This makes it difficult to balance corrosion prevention and energy efficiency, resulting in lengthy processes and significant energy waste.

[0005] Therefore, developing a synergistic technical solution that can solve the corrosion problem at its source while simultaneously optimizing the process, improving heat recovery efficiency, and reducing circulating water consumption has become a critical technical bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0006] The core objective of this invention is to overcome the shortcomings of existing technologies and provide a sulfur-resistant conversion corrosion-resistant process for synthetic ammonia, achieving a multi-objective synergy of "corrosion prevention, high heat recovery, and low circulating water consumption," thus solving the technical problems of poor corrosion resistance, complex processes, and low energy efficiency in existing technologies.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A sulfur-resistant and corrosion-resistant process for synthetic ammonia conversion includes the following steps:

[0009] S1. Gas-liquid pretreatment: crude water gas is drawn from the carbon scrubbing tower, and the first material is obtained through gas-liquid separation. The second material is obtained after heat exchange of the first material.

[0010] S2, Filtration and First-Stage Shift: After removing impurities from the second material through a filter, the third material is obtained. The third material is then fed into the first shift furnace to carry out the first shift reaction, generating the first shift product.

[0011] S3, Heat recovery and secondary conversion: The first conversion product is heat-exchanged to obtain conversion gas. The conversion gas is sent to a medium-pressure steam generator to recover heat and obtain the fourth material. The fourth material is fed into the second conversion furnace to carry out the second conversion reaction and generate the second conversion product.

[0012] S4. Cooling and condensation separation: The second conversion product is heated by a low-pressure steam generator to obtain the fifth material. The fifth material is then passed into the second separator to separate the condensate and obtain the sixth material. The sixth material is then fed into the demineralized water preheater and water cooler to cool down and obtain ambient temperature gas-liquid mixed conversion gas.

[0013] S5. Ammonia washing and corrosion control: Ambient temperature gas-liquid mixed shift gas is introduced into the ammonia washing tower. After washing, the condensate is separated to obtain ambient temperature shift gas. The bottom outlet pipeline of the ammonia washing tower is connected to an online pH analyzer to monitor the pH value of the process condensate at the bottom outlet of the ammonia washing tower in real time and maintain the pH value of the process condensate within the range of 6.5-8.5.

[0014] In step S1, the gas-liquid separation is achieved using a first separator, and the heat exchange process is completed through a gas preheater. After heat exchange, the temperature of the second material is controlled at 280-320℃.

[0015] In step S2, the filter uses sulfur-resistant and corrosion-resistant filter material with a filtration accuracy of 1-5 μm; the temperature of the first conversion reaction is 350-400℃ and the pressure is 3.0-4.0 MPa; the first conversion furnace is filled with a cobalt-molybdenum-based sulfur-resistant conversion catalyst.

[0016] In step S3, the medium-pressure steam generator is a medium-pressure waste boiler, which recovers heat to generate medium-pressure steam at 3.8-4.2 MPa; the temperature of the second conversion reaction is 220-280℃ and the pressure is 2.8-3.5 MPa, and the second conversion furnace is filled with a cobalt-molybdenum based sulfur-resistant conversion catalyst.

[0017] In step S3, the first conversion product is cooled by heat exchange in a steam superheater to obtain conversion gas, and the temperature of the conversion gas after heat exchange is controlled at 300-330℃.

[0018] In step S4, the low-pressure steam generator is a low-pressure waste boiler, which recovers heat to generate low-pressure steam of 0.8-1.2MPa; the sixth material is preheated with demineralized water by a demineralized water preheater and then cooled to 30-40℃ by a water cooler to obtain ambient temperature gas-liquid mixed shift gas.

[0019] In step S5, the ammonia washing tower uses demineralized water as the washing medium.

[0020] This invention addresses the shortcomings of existing technologies that employ "end-of-pipe treatment" methods (such as alkali neutralization and corrosion-resistant materials), which fail to solve the problem of acidic medium accumulation at its source. This invention proposes a proactive corrosion prevention approach of "pre-treatment ammonia removal + real-time monitoring and control." By removing NH3 pre-processed in an ammonia washing tower, the relative accumulation of acidic media after NH3 separation is reduced. Simultaneously, an online pH analyzer monitors the pH value of the condensate in real time, allowing for timely adjustment of the washing liquid flow rate. This inhibits the ionization of acidic media at its source, completely changing the "passive corrosion response" approach of existing technologies. The corrosion prevention effect is more stable and durable, and it avoids secondary problems caused by adding corrosion inhibitors or end-of-pipe alkali.

[0021] In existing technologies, the shift reaction, heat recovery, and corrosion prevention are independent processes, resulting in lengthy procedures, redundant equipment, and significant energy losses. This invention integrates "gas-liquid pretreatment - two-stage shift reaction - cascaded heat recovery - ammonia washing and corrosion prevention" into a closed-loop process. Through a cascaded design of a medium-pressure waste boiler, a low-pressure waste boiler, and a demineralized water preheater, it fully recovers waste heat from each stage of the shift reaction, generating steam at different pressure levels to preheat the demineralized water. The heat recovery efficiency is 12%-15% higher than existing technologies. Simultaneously, process optimization shortens material transport paths, reduces equipment and pipeline investment, and lowers initial investment and floor space requirements.

[0022] Addressing the limitations of existing technologies that only address corrosion prevention or energy efficiency individually, this invention achieves a multi-objective synergy of "corrosion prevention, high CO conversion rate, high heat recovery efficiency, and low circulating water consumption." On one hand, the two-stage conversion reaction ensures a total CO conversion rate of ≥98.5%, meeting the requirements for ammonia synthesis feedstock. On the other hand, the cascaded heat recovery reduces the cooling load on the water cooler, lowering circulating water consumption by 18%-20%. Simultaneously, the proactive corrosion prevention design avoids equipment corrosion, extends equipment lifespan, and reduces maintenance costs, resolving the technical contradiction of "difficulty in balancing corrosion prevention and energy efficiency" in existing technologies, thus achieving significant technological progress.

[0023] The beneficial effects of this invention are:

[0024] 1. Significant corrosion prevention effect: Through the active corrosion prevention design of "ammonia washing and deammoniation + real-time pH monitoring and control", the acidification of condensate is inhibited from the source. The pH value of the process condensate is stabilized at 6.5-8.5, and there is no obvious corrosion of equipment and pipelines. The service life is extended by more than 30%, and maintenance costs and safety risks are greatly reduced.

[0025] 2. High heat recovery efficiency: The cascade heat recovery system makes full use of the waste heat from the conversion reaction to generate medium-pressure and low-pressure steam and preheat demineralized water. The heat recovery efficiency is 12%-15% higher than that of existing technologies, significantly reducing energy consumption.

[0026] 3. Low circulating water consumption: The optimized cooling process reduces the material temperature in advance through waste heat recovery, thereby reducing the cooling load on the water cooler and reducing circulating water consumption by 18%-20%, saving water resources and operating costs.

[0027] 4. Stable and reliable operation: The filter removes impurities to avoid catalyst deactivation, the two-stage conversion ensures high CO conversion rate, real-time pH monitoring and flow control stabilize process parameters, and the product gas quality qualification rate is ≥99.5%. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the sulfur-resistant conversion corrosion-resistant process for synthesizing ammonia according to the present invention;

[0029] The markings in the diagram are: A - First separator, B - Gas preheater, C - Filter, D - First converter, E - Steam superheater, F - Medium-pressure waste boiler, G - Second converter, H - Low-pressure waste boiler, I - Second separator, J - Demineralized water preheater, K - Water cooler, L - Ammonia washing tower. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0031] like Figure 1 As shown, a sulfur-resistant conversion corrosion-resistant process for synthetic ammonia involves equipment connected sequentially via pipelines, including a first separator A, a gas preheater B, a filter C, a first converter D, a steam superheater E, a medium-pressure waste boiler F, a second converter G, a low-pressure waste boiler H, a second separator I, a demineralized water preheater J, a water cooler K, an ammonia washing tower L, and an online pH analyzer, forming a closed-loop system of "pretreatment-reaction-recovery-corrosion prevention." The specific steps are as follows:

[0032] S1. Gas-liquid pretreatment: The crude water gas drawn from the carbon scrubbing tower first enters the first separator A for gas-liquid separation to remove free water and some solid impurities, obtaining the first material; the first material is sent to the gas preheater B for heat exchange and heating to 280-320℃ to obtain the second material, providing suitable temperature conditions for subsequent conversion reactions and avoiding the problem of low reaction efficiency caused by low temperature.

[0033] S2. Filtration and First-Stage Conversion: The second material is passed into filter C, which uses sulfur-resistant and corrosion-resistant filter media (such as sulfur-resistant ceramics or sulfur-resistant alloys) with a filtration accuracy of 1-5μm. This effectively removes solid particulate impurities from the material and prevents catalyst poisoning and deactivation, resulting in the third material. The third material is then fed into the first conversion furnace D, which is filled with a cobalt-molybdenum-based sulfur-resistant conversion catalyst. The first conversion reaction is carried out at 350-400℃ and 3.0-4.0MPa, converting most of the CO into CO2 and H2, generating the first conversion products. The CO conversion rate can reach 82%-85%.

[0034] S3. Heat Recovery and Secondary Shift Conversion: The first shift product is fed into a steam superheater E for heat exchange and cooling to 300-330℃ to obtain shift gas; the shift gas is fed into a medium-pressure waste boiler F to recover the heat of the high-temperature shift gas to generate medium-pressure steam at 3.8-4.2MPa, achieving efficient energy utilization. After heat exchange, the fourth material is obtained; the fourth material is fed into a second shift furnace G filled with a cobalt-molybdenum based sulfur-resistant shift catalyst, where a second shift reaction is carried out at 220-280℃ and 2.8-3.5MPa to further improve the CO conversion rate. The total conversion rate can reach over 98.5%, generating the second shift product.

[0035] S4. Cooling and Condensation Separation: The second conversion product is fed into the low-pressure waste boiler H to recover heat and generate low-pressure steam of 0.8-1.2 MPa. After heat exchange, the fifth material is obtained. The fifth material is fed into the second separator I to separate part of the condensate and obtain the sixth material. The sixth material is fed into the demineralized water preheater J to preheat the demineralized water using waste heat, realizing cascade heat recovery. Then it enters the water cooler K to be cooled to 30-40℃ to obtain ambient temperature gas-liquid mixed conversion gas. At this time, the material temperature is reduced, creating conditions for subsequent ammonia washing and corrosion control.

[0036] S5. Ammonia Washing and Corrosion Control: Ambient temperature gas-liquid mixed shift gas is introduced into the ammonia washing tower L. Demineralized water is used as the washing medium to wash away NH3 and some acidic media from the material. After separating the condensate, qualified ambient temperature shift gas (NH3 content ≤ 0.001%) is obtained. The bottom outlet pipeline of the ammonia washing tower is connected to an online pH analyzer (monitoring accuracy ±0.01pH) to monitor the pH value of the process condensate in real time. The washing liquid flow rate of the ammonia washing tower is adjusted using existing conventional control methods. When the pH value is below 6.5, the washing liquid flow rate is increased to enhance NH3 removal and acidic media dilution. When the pH value is above 8.5, the washing liquid flow rate is reduced to avoid water waste and maintain the pH value of the process condensate in the neutral range of 6.5-8.5, inhibiting acid corrosion from the source.

[0037] This invention employs an active corrosion prevention design of "ammonia washing and deammoniation + real-time pH monitoring and control" to inhibit condensate acidification at the source. The pH value of the process condensate is stabilized at 6.5-8.5, resulting in no significant corrosion of equipment and pipelines, extending service life by more than 30%, and significantly reducing maintenance costs and safety risks.

[0038] High heat recovery efficiency: The cascade heat recovery system makes full use of the waste heat from the conversion reaction to generate medium- and low-pressure steam and preheat demineralized water. The heat recovery efficiency is 12%-15% higher than that of existing technologies, significantly reducing energy consumption.

[0039] Low circulating water consumption: The cooling process is optimized, and the material temperature is reduced in advance through waste heat recovery, which reduces the cooling load of the water cooler and reduces circulating water consumption by 18%-20%, saving water resources and operating costs.

[0040] Stable and reliable operation: The filter removes impurities to prevent catalyst deactivation, the two-stage conversion ensures high CO conversion rate, real-time pH monitoring and flow control stabilize process parameters, and the product gas quality qualification rate is ≥99.5%.

[0041] Example 1

[0042] A sulfur-resistant and corrosion-resistant process for synthetic ammonia conversion includes the following steps:

[0043] S1 Gas-Liquid Pretreatment: The crude water gas (composition: CO2 8%, H2 35%, CO2 22%, H2S 0.8%, COS 0.1%, NH3 0.05%, the remainder being N2 and saturated water vapor) drawn from the carbon scrubbing tower enters the first separator A for gas-liquid separation to obtain the first material; the first material is sent to the gas preheater B for heat exchange to 300℃ to obtain the second material.

[0044] S2 Filtration and First-Stage Conversion: The second material is passed into filter C (the filter media is sulfur-resistant ceramic with a filtration accuracy of 3μm) to remove solid particulate impurities and obtain the third material; the third material is sent into the first conversion furnace D (filled with cobalt-molybdenum-based sulfur-resistant conversion catalyst) and the first conversion reaction is carried out at a temperature of 380℃ and a pressure of 3.5MPa, with the CO conversion rate reaching 85% and the first conversion product being generated.

[0045] S3 Heat Recovery and Secondary Conversion: The first conversion product is sent to the steam superheater E for heat exchange and cooling to 320℃ to obtain conversion gas; the conversion gas is sent to the medium-pressure waste boiler F to recover heat and generate medium-pressure steam at 4.0MPa. After heat exchange, the fourth material at 260℃ is obtained; the fourth material is sent to the second conversion furnace G (filled with cobalt-molybdenum-based sulfur-resistant conversion catalyst) to carry out the second conversion reaction at a temperature of 250℃ and a pressure of 3.2MPa, with the total CO conversion rate reaching 99%, generating the second conversion product.

[0046] S4 Cooling and Condensation Separation: The second conversion product is fed into the low-pressure waste boiler H to recover heat and generate low-pressure steam at 1.0 MPa. After heat exchange, the fifth material at a temperature of 180℃ is obtained. The fifth material is fed into the second separator I to separate the condensate and obtain the sixth material. The sixth material is fed into the demineralized water preheater J to preheat the demineralized water (the temperature of the demineralized water is raised from 25℃ to 120℃), and then enters the water cooler K to cool to 35℃ to obtain ambient temperature gas-liquid mixed conversion gas.

[0047] S5 Ammonia Washing and Corrosion Control: Ambient temperature gas-liquid mixed shift gas is introduced into ammonia washing tower L, and demineralized water is used as the washing liquid for washing. After separating the condensate, ambient temperature shift gas (NH3 content ≤ 0.001%) is obtained. The bottom outlet pipeline of ammonia washing tower L is connected to an online pH analyzer (monitoring accuracy ±0.01pH) to monitor the pH value of the process condensate in real time. The washing liquid flow rate is manually adjusted. When the pH value is below 6.5, the washing liquid flow rate is increased, and when the pH value is above 8.5, the washing liquid flow rate is decreased to maintain the pH value of the process condensate within the range of 7.0-8.0.

[0048] This embodiment operated continuously for 180 days, and there were no signs of corrosion on the stainless steel equipment and pipelines in the conversion section. The equipment operated stably. The heat recovery efficiency was increased by 15% compared with the traditional process, the circulating water consumption was reduced by 20%, and the total CO conversion rate remained stable at over 99%, fully meeting the requirements for synthetic ammonia production.

[0049] Example 2

[0050] A sulfur-resistant and corrosion-resistant process for synthetic ammonia conversion includes the following steps:

[0051] S1 Gas-Liquid Pretreatment: The crude water gas drawn from the carbon scrubbing tower enters the first separator A for gas-liquid separation to obtain the first material; the first material is sent to the gas preheater B for heat exchange to 280°C to obtain the second material.

[0052] S2 Filtration and First-Stage Conversion: The second material is passed into filter C (the filter media is a sulfur-resistant alloy with a filtration accuracy of 1μm) to obtain the third material; the third material is sent to the first conversion furnace D, where the first conversion reaction is carried out at a temperature of 350℃ and a pressure of 3.0MPa, and the CO conversion rate reaches 82%, generating the first conversion product.

[0053] S3 Heat Recovery and Secondary Conversion: The first conversion product is sent to the steam superheater E for heat exchange and cooling to 300℃ to obtain conversion gas; the conversion gas is sent to the medium-pressure waste boiler F to generate medium-pressure steam at 3.8MPa, and after heat exchange, the fourth material at 240℃ is obtained; the fourth material is sent to the second conversion furnace G, where the second conversion reaction is carried out at a temperature of 220℃ and a pressure of 2.8MPa, and the total CO conversion rate reaches 98.5%, generating the second conversion product.

[0054] S4 Cooling and Condensation Separation: The second conversion product is fed into the low-pressure waste boiler H to generate low-pressure steam at 0.8 MPa. After heat exchange, the fifth material at a temperature of 160°C is obtained. The fifth material is fed into the second separator I to separate the condensate and obtain the sixth material. The sixth material is fed into the demineralized water preheater J to preheat the demineralized water (the temperature of the demineralized water rises from 20°C to 110°C), and then enters the water cooler K to cool to 30°C to obtain ambient temperature gas-liquid mixed conversion gas.

[0055] S5 Ammonia Washing and Corrosion Control: Ambient temperature gas-liquid mixed shift gas is introduced into ammonia washing tower L, and after washing with demineralized water, ambient temperature shift gas is obtained; the pH value of the process condensate is monitored in real time by an online pH analyzer, and the flow rate of the washing liquid is adjusted by a conventional automatic flow control device to maintain the pH value of the process condensate within the range of 6.5-7.5.

[0056] In this embodiment, the equipment operated continuously for 150 days without corrosion failure, the heat recovery efficiency was increased by 12%, the circulating water consumption was reduced by 18%, and the total CO conversion rate remained stable at over 98.5%, meeting the requirements of industrial production.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent substitutions, improvements, etc., made by those skilled in the art based on the technical solution and inventive concept of the present invention should be included within the protection scope of the present invention.

Claims

1. A sulfur-resistant and corrosion-resistant process for synthetic ammonia conversion, characterized in that, Includes the following steps: S1. Gas-liquid pretreatment: crude water gas is drawn from the carbon scrubbing tower, and the first material is obtained through gas-liquid separation. The second material is obtained after heat exchange of the first material. S2, Filtration and First-Stage Shift: After removing impurities from the second material through a filter, the third material is obtained. The third material is then fed into the first shift furnace to carry out the first shift reaction, generating the first shift product. S3, Heat recovery and secondary conversion: The first conversion product is heat-exchanged to obtain conversion gas. The conversion gas is sent to a medium-pressure steam generator to recover heat and obtain the fourth material. The fourth material is fed into the second conversion furnace to carry out the second conversion reaction and generate the second conversion product. S4. Cooling and condensation separation: The second conversion product is heated by a low-pressure steam generator to obtain the fifth material. The fifth material is then passed into the second separator to separate the condensate and obtain the sixth material. The sixth material is then fed into the demineralized water preheater and water cooler to cool down and obtain ambient temperature gas-liquid mixed conversion gas. S5. Ammonia washing and corrosion control: Ambient temperature gas-liquid mixed shift gas is introduced into the ammonia washing tower. After washing, the condensate is separated to obtain ambient temperature shift gas. The bottom outlet pipeline of the ammonia washing tower is connected to an online pH analyzer to monitor the pH value of the process condensate at the bottom outlet of the ammonia washing tower in real time and maintain the pH value of the process condensate within the range of 6.5-8.

5.

2. The sulfur-resistant conversion corrosion-resistant process for synthetic ammonia according to claim 1, characterized in that, In step S1, the gas-liquid separation is achieved using a first separator, and the heat exchange process is completed through a gas preheater. After heat exchange, the temperature of the second material is controlled at 280-320℃.

3. The sulfur-resistant conversion corrosion-resistant process for synthetic ammonia according to claim 1, characterized in that, In step S2, the filter uses sulfur-resistant and corrosion-resistant filter material with a filtration accuracy of 1-5 μm; the temperature of the first conversion reaction is 350-400℃ and the pressure is 3.0-4.0 MPa; the first conversion furnace is filled with a cobalt-molybdenum-based sulfur-resistant conversion catalyst.

4. The sulfur-resistant conversion corrosion-resistant process for synthetic ammonia according to claim 1, characterized in that, In step S3, the medium-pressure steam generator is a medium-pressure waste boiler, which recovers heat to generate medium-pressure steam at 3.8-4.2 MPa; the temperature of the second conversion reaction is 220-280℃ and the pressure is 2.8-3.5 MPa, and the second conversion furnace is filled with a cobalt-molybdenum based sulfur-resistant conversion catalyst.

5. The sulfur-resistant conversion corrosion-resistant process for synthetic ammonia according to claim 1, characterized in that, In step S3, the first conversion product is cooled by heat exchange in a steam superheater to obtain conversion gas, and the temperature of the conversion gas after heat exchange is controlled at 300-330℃.

6. The sulfur-resistant conversion corrosion-resistant process for synthetic ammonia according to claim 1, characterized in that, In step S4, the low-pressure steam generator is a low-pressure waste boiler, which recovers heat to generate low-pressure steam of 0.8-1.2MPa; the sixth material is preheated with demineralized water by a demineralized water preheater and then cooled to 30-40℃ by a water cooler to obtain ambient temperature gas-liquid mixed shift gas.

7. The sulfur-resistant conversion corrosion-resistant process for synthetic ammonia according to claim 1, characterized in that, In step S5, the ammonia washing tower uses demineralized water as the washing medium.

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