Why is it necessary to stop feeding water into the reaction effluent when the inlet temperature of the hydrorefining reactor is 260°C?
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In a hydrocracking operating procedure, it is stated: \"When the inlet temperature of reactor R1001 reaches 260°C, water injection into the reaction effluent must be stopped.\" "Does anyone know what the considerations behind this are?
Stopping the reaction water injection can reduce the depth of the reaction. Hydrocracking catalysts are bifunctional catalysts, possessing both hydrogenation and cracking functions. It is the acidic centers on the catalyst that enable the cracking process; these acidic centers readily adsorb the basic NH3. After water injection is stopped in the reaction, the amount of NH3 in the recycle hydrogen increases significantly. The large amount of NH3 that adsorbs onto the acidic centers on the catalyst leads to a significant reduction in the number of such centers, which in turn reduces the degree of reaction, especially the degree of cracking. This helps to prevent secondary reactions from occurring and thus reduces the production of gaseous products.
The classmate upstairs is right, but that’s not what I wanted to ask. By the time the temperature drops to 260 degrees during the shutdown, it’s already after heat hydrogen stripping, so no reaction should be taking place! Please keep helping to answer my question!
After 260 degrees, the reaction essentially stops, and no ammonium salts are formed in the reaction products; therefore, there is no need to add water anymore.