What to do when the activity of the synthetic catalyst declines and the system pressure exceeds the limit?
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This post was last edited by E Dong Du Lang on 2011-6-4 01:19. As the synthetic catalyst ages, its activity declines, which in turn affects the efficiency of the ammonia synthesis reaction. The pressure in the synthesis system also increases over time. What will people do when the pressure exceeds the acceptable level? Our company used to increase the temperature of the hot spots, boost the hydrogen recovery capacity, and carry out production using electric furnaces; sometimes we would also simply vent the gas after starting up the tower ； It seems that the energy consumption and coal consumption for ammonia production are quite high at this time. Do anyone have any other approaches?
I think it’s better to replace the catalyst!
Increase the hotspot temperature and optimize other parameters; if that doesn’t work, replace the catalyst
Raising the hotspot temperature is temporary; ultimately, the catalyst needs to be replaced
For comparison, one can look at the increased electricity consumption and ammonia production cost resulting from replacing the catalyst while the plant is shut down, versus those associated with keeping the plant running by using a heated furnace and venting gas – which option results in higher costs? The answer is then clear.
It can only be maintained until a major overhaul to replace the catalyst.
These days, most factories increase the temperature of the hot spots, reduce the amount of inert gases, and use electric furnaces… All these measures are aimed at increasing the activity of the catalysts. Reducing the system pressure allows production to continue; replacing the catalysts is the main solution. Everything else is done to enhance the catalyst’s activity. Here, we replace the catalyst in our furnaces every three years···
There is no good solution to the problem of catalyst aging in ammonia synthesis; as the other users mentioned above, measures such as raising the temperature at the catalyst’s hot spots, controlling the gas composition (i.e., increasing the hydrogen content in the feed gas), increasing the amount of hydrogen being produced (by adjusting the amount of air released), operating the electric furnace while it is powered on, and replacing the catalysts in the upper sections can be taken. However, the most fundamental solution is to shut down the plant and replace all the catalysts in the tower.
Thank you all. Our factory’s previous batch of catalysts lasted for 5 years, and the performance of this batch is quite good as well； The experienced craftsmen all say that it’s rare to come across a good batch of catalysts, so it’s important to take good care of this batch.
All of them have a lifespan of ten years; the key is gas purification. Pre-reduced catalysts are not reliable, while those in the oxidized state should not present much of a problem
Iron catalysts are cheap, so why not replace them directly? Following the method suggested by the original poster, I think it’s not worth the effort