12. Weekly Topics on Ammonia Synthesis Knowledge 19
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Why is it necessary to control the inlet temperature at a minimum level when various catalysts used in the ammonia synthesis process are put into operation only after completion of the heating and reduction process?
Operation at low load to protect the catalyst; the inlet temperature determines the reaction conditions in the synthesis tower
Since the new catalyst has high activity at the beginning of use, the inlet temperature should be kept as low as possible, taking advantage of its activity at low temperatures. As the catalyst loses its activity due to aging or poisoning during operation, the inlet temperature needs to be increased gradually in order to maintain a sufficient production capacity and boost the catalyst’s reaction speed.
Since the catalyst has just been reduced and thus has high activity, the inlet temperature is kept at the lower limit of the process specifications in order to fully utilize its low-temperature activity; the inlet temperature is then increased gradually as the catalyst’s activity declines. This makes the use of the catalyst more reasonable!
Is it correct that the inlet temperature of the Kashali synthesis tower is 200 degrees and the wall temperature of the tower is 150 degrees? Can someone explain it to me?
To prevent uncontrolled reactions from occurring in partially unreduced CAT. It’s mainly for insurance, to protect the CAT.
I tend to agree with what was said on the third floor: at the beginning, the catalyst has good activity, and it is necessary to control the inlet temperature to prevent the catalyst from overheating. The catalysts produced by Zhejiang University cannot be used at temperatures higher than 500°C.
When a new catalyst is first put into use, it has high activity; therefore, the inlet temperature should be kept as low as possible. By taking advantage of this low-temperature activity, it is possible to prevent the catalyst from being damaged due to excessive heat resulting from its high activity. After being used for some time, the catalyst’s activity decreases due to aging and poisoning. To enhance the catalyst’s reaction efficiency, it is necessary to maintain a higher catalyst temperature later on, and one way to do this is by increasing the inlet temperature
Reply to 10# zuo923: It is not easy to experience overheating during operation; the new catalyst has good activity at low temperatures. At higher temperatures, crystal growth occurs rapidly, the catalyst ages quickly, and its useful life is short.
The activation temperature of the catalyst and the design temperature limit of the tower wall
When a new catalyst is first put into use, it has high activity; therefore, the inlet temperature should be kept as low as possible. By taking advantage of this low-temperature activity, it is possible to prevent the catalyst from being damaged due to excessive heat resulting from its high activity. After being used for some time, the catalyst’s activity decreases due to aging and poisoning. To improve the catalyst’s reaction efficiency, one method of ensuring normal operation is to increase the inlet temperature.