The A110 has been in use in our country for many years, with satisfactory performance. What is the optimal reaction temperature for different processes?

The optimal hot spot temperature for the Topsoo Process A110 should be between 490 and 500 degrees. In the initial stage of use, maintain a low temperature as much as possible while meeting the load requirements; in the later stages of catalyst use, the hotspot temperature can be increased, even up to the catalyst’s maximum tolerance temperature. Permanent poisoning has occurred, and it is impossible to analyze it ； In the case of temporary poisoning, the catalyst will be re-activated as the process gas is introduced. The obvious signs of degradation are first a decrease in production capacity; other symptoms include a reduction in the ammonia net value, a significant increase in the inlet temperatures at various stages, and an increase in the pressure drop across the tower.

My workshop is equipped with a three-bed synthesis tower in Cassali; the catalyst used is A110-1, and its optimal reaction temperature ranges from 470 to 490 degrees. It is essential to strictly control the amount of substances that enter the synthesis tower – this amount varies depending on the gas production method employed. During maintenance, the synthesis tower must be protected with a slight positive pressure of nitrogen to prevent oxygen from reaching the catalyst and causing oxidation. Overheating of the synthesis tower must be avoided at all costs, as it can damage the catalyst; if permanent poisoning occurs, the catalyst will need to be replaced； In the case of temporary poisoning, the methods have been outlined above. An obvious sign of decreased catalyst activity is a drop in the synthesis rate, a reduction in the ammonia content in the gas exiting the synthesis tower, an increase in the volume of recycled gas, and an increase in compression work. The net ammonia yield decreases as well

May I ask what is the production capacity of your factory upstairs in ten thousand tons, what is the system pressure, and what type of gas is it? What purification process is used in the previous stage? I’d like some advice. Hehe. :)

Our company’s old systems have long used A110-1 and NC-1200 synthesis towers, with a maximum service life of nearly 5 years. The operating temperature generally ranges from 370 to 480°C. It is important to maintain the quality of the gas during operation, preventing the presence of ammonia and oil contaminants, as well as avoiding large fluctuations in temperature. Over time, the temperature can be gradually increased to 500°C. The degree of degradation in performance can be determined by examining the level of inert gases present and the sensitivity to temperature changes.

A medium-sized factory in China used it once; its application in the YD four-stage quenching 1000 tower was not very successful. It seems that this type of catalyst has a high activation temperature – it requires 400–420 degrees to operate stably at the inlet, while A202Q only needs 360–380 degrees to become active.

The key to determining the duration of catalyst use lies in purification; if substances that are harmful to the catalyst are removed thoroughly, I believe the catalyst can be used for 10 years or even longer. Of course, this depends on the characteristics of the process. For example, in our facility, the low-temperature shift catalyst is used alongside reciprocating compressors, which present serious oil-related problems. Even with the use of filters and regular checks of the oil discharge, it is still not possible to resolve these issues fundamentally. In our facility, I think the A110 performs very well. When the compressor is in good condition, it can handle 660–670 MTPD; the pressure remains below 13.5 MP, the temperature at the hot spot is around 480 degrees, the ammonia purity is about 14%, and the circulation rate is 320 K.

The A110 has been operating at full capacity in a large domestic plant for 17 years; its catalyst volume is 28 M3, and the purification processes involve methanol washing and liquid nitrogen washing. It is equipped with TOPSOE internals, with initial hotspot temperatures of 490, intermediate hotspot temperatures of 500, and final hotspot temperatures of 510. In the case of temporary poisoning, reducing the pressure and increasing the temperature can help, and the issue should be resolved after one or two shifts of operation

Personally, I think you haven’t done a good job of restoration; it’s also necessary to analyze the gas composition. The two 1000-tank units in our old ammonia plant’s YD system have been in operation for 15 years now. The inlet temperature at the first stage can generally be maintained around 360 degrees. The quality of the gas is not good; copper washing is used for treatment, and the trace amount of impurities often exceeds 30 ppm. These units usually last 3 to 5 years.

I just read a piece of material on the Casali process; it mentioned that A110 catalyst is used, with a production capacity of 300 tons per day, and the operating temperature at the hot spot is 490 degrees. However, I think their reduction process isn’t optimal, as the inlet temperature is a bit too high at 380 degrees. With such a large volume of material, the inlet temperature could actually be reduced to 360 degrees. This allows for a large amount of reaction space. Personal opinion!

The catalyst is A110, and its optimal reaction temperature is 450–475..

For catalysts, there indeed is an optimal activity temperature. However, for the ammonia synthesis reaction, depending on the different synthesis reactors and processes, there is also an optimal equilibrium temperature, and this primarily depends on the process itself. Therefore, when discussing different production capacities as mentioned earlier, it is necessary to assign an appropriate space velocity in order to achieve the most suitable temperature, thereby reducing energy consumption and increasing the reaction conversion rate/