Weekly Topic for Ammonia Production: How to Extend the Service Life of Catalysts?

1. Prevent toxins from entering the catalyst bed, thereby avoiding catalyst poisoning. 2. Strictly prevent the catalyst from overheating, which could cause its sintering. 3. During startup and shutdown, the speed of pressure increase and decrease must be slow, and the process specifications must be strictly followed. 4. Prevent water-containing gases from entering the catalyst bed, which could cause the catalyst to become pulverized. 5. Prevent dirt from entering the catalyst bed, which could clog the catalyst’s micropores and lead to a decrease in its activity. 6. Nitrogen should be used to protect the catalyst during parking for maintenance.

Haha, Yan’s version is really early – have a great Sunday! Measures to extend the catalyst’s service life: 1. Ensure gas quality ； 2. The production load should be increased or decreased slowly and steadily ； 3. Strictly enforce the process parameters for peak temperature ； 4. Ensure proper catalyst protection measures are in place when shutting down.

To extend the service life of the catalyst, the following measures should be taken during production: 1. Reduce the frequency of starting and stopping the process; frequent start-ups and stoppages can cause the catalyst to crack or degrade due to irregular changes in temperature and pressure. 2. During start-up and shutdown, strictly control the rate at which temperature and pressure are changed, to prevent damage to the catalyst caused by too rapid changes. 3. Over-temperature and over-pressure conditions must be avoided during production. 4. Prevent catalyst poisons such as sulfur and chlorine from entering the catalyst bed. 5. Prevent steam from condensing within the catalyst bed, as well as the entry of condensate or water into the bed. 6. Avoid overloading the catalyst bed during operation, as this can reduce its activity. 7. After shutting down the process, take proper measures to protect the catalyst, preventing it from oxidizing or becoming deactivated. 8. When reducing the catalyst for the first time, do so thoroughly to ensure high catalyst activity. 9. In the early stages of using the catalyst, operate it at lower temperatures within its active temperature range, and increase the temperature only later in its usage life. Because generally, catalysts lose their activity at low temperatures when used at high temperatures

I used to work in ammonia synthesis, and I think the key aspects are mainly the following: 1. Strictly control the temperature at each stage of the synthesis tower, striving to maintain a stable synthesis temperature. 2. Control the H/N ratio in the syngas appropriately, control the content of impurity gases such as carbon monoxide, carbon dioxide, sulfur dioxide, etc., control the appropriate methane content, and control the reaction rate. 3. When starting up or shutting down, prevent sharp rises and falls in tower temperature by controlling the rate of temperature change. 4. Regularly clean the catalyst and screen for replacement. We will start from these aspects mainly, though there are other factors as well.

1. Design aspect: Based on the theoretical properties of the catalyst, it is essential to design appropriate reactors and operating parameters; this is the foundation upon which reactor operation relies, as the prerequisites determine the outcomes. 2. In terms of operation: Everything meets the design requirements. Once the design parameters of the reactor are determined, the limits that the reaction can reach are also fixed; it is not possible to operate beyond these limits. All you need to do is find ways to maintain the conditions of the reactor, without thinking about how to change those conditions. 3. Operational level: Level is everything; meeting the above conditions will satisfy the basic operational requirements, but it is still a long way from a high level. What you can do is to bring your actual operational performance as close as possible to the theoretical standard, with as few fluctuations as possible.

1. Reduce the frequency of starting and stopping the process; frequent starts and stops can cause the catalyst to crack or degrade due to irregular changes in temperature and pressure. 2. During start-up and shutdown, strictly control the rate at which temperature and pressure are changed, in order to prevent damage to the catalyst caused by too rapid changes. 3. It is strictly prohibited to allow temperatures or pressures to exceed their limits during production. 4. Prevent catalyst poisons such as sulfur and chlorine from entering the catalyst bed. 5. Prevent steam from condensing within the catalyst bed, as well as the entry of condensate or water into the bed. 6. Avoid overloading the catalyst bed during operation, as this can reduce its activity. 7. After shutting down the process, take proper measures to protect the catalyst, preventing it from oxidizing or becoming deactivated. 8. When reducing the catalyst for the first time, ensure that the reduction is thorough, so as to maintain high catalyst activity

Choose a good catalyst. Secondly, follow the catalyst reduction procedure strictly to prevent shutdowns during the reduction process. Ensure an adequate period of low-load operation; it is strictly forbidden to increase the load ahead of time. Be careful to avoid operation at excessive temperatures or pressures. Proper gas purification is necessary, and substances that could poison the catalyst must not enter the catalyst bed. Large fluctuations in operating conditions, especially in terms of temperature, pressure, and pressure differences, should be avoided. Proper protection of the catalyst is essential every time it is shut down. In some plants, ammonia synthesis catalysts can last for over 20 years, so there is much room for improvement

The purification workshop must pay close attention to the analysis data of coke oven gas; any abnormal values should be reported promptly. It is necessary to strictly control the sulfur compound content in the feed gas, as well as the total sulfur level at the dry exhaust point, and the level of the conversion waste fluid. High liquid levels can cause water to enter the conversion furnace, leading to catalyst degradation, increased resistance, and reduced activity； Enhance the drainage of steam to prevent condensate from entering the conversion furnace, where it could come into contact with the hot catalyst and cause it to disintegrate. At the same time, strict process discipline must be maintained, with enhanced supervision and inspection as well as rigorous evaluation; employees’ emergency response capabilities should be improved, operations carried out with precision and stability, and the peak temperature of the catalyst strictly controlled.