The heat exchange efficiency of the slurry-feed oil heat exchanger has declined, preventing an increase in the preheating temperature of the feed oil
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The heat exchange efficiency of the oil slurry-to-feed oil heat exchanger in my catalytic unit has declined, which prevents the feed oil from reaching its desired preheating temperature. The normal temperature should be 230 degrees, but currently it can only be maintained at 220 degrees. It’s not possible to shut down the oil slurry heat exchanger at the moment, and the planned maintenance is scheduled for October next year. Are there any ways to increase the preheating temperature?
When the device is operating stably, mention the temperatures of other media used for heat exchange with the crude oil; if there is a furnace, it can be used to heat the crude oil.
You can try backwashing the slurry heat exchanger with flushing oil. If the slurry circulation rate can be maintained, production can be continued by adjusting the process operations simply by reducing the preheating temperature of the raw materials. Lowering the preheating temperature of the feedstock and increasing the catalyst-oil ratio can help maintain catalyst activity for production; however, an increased catalyst-oil ratio also leads to a relatively higher load on regeneration and coking.
Increase the temperature of the raw material tank and raise the heating steam flow, thereby increasing the filling temperature. Direct supply of raw materials can increase the discharge temperature of vacuum distillation wax oil.
The first step is to raise the inlet temperature of the wax oil and residue in the raw material tank area to the plant. The second step is to increase the temperature of the oil slurry returning to the distillation column from the bottom of the column, thereby increasing the amount of oil slurry that moves up and down in the column and enhancing heat exchange with the oil in the middle section. Hope this helps!
One can try to increase the heat exchange temperature of each heat exchanger before the slurry heat exchanger.
This estimate is mainly due to scaling in the slurry heat exchanger, and efforts should be focused on reducing and preventing scaling! 1. Increase the dosage of the slurry scale inhibitor. 2. The oil slurry heat exchanger can be flushed with flushing oil. 3. It is recommended to use an ultrasonic descaling device; we have used one here and the results have been excellent! PS: The preheating temperature of 220–230 has little impact on the behavior of the feed oil in the catalytic cracking reaction. When we used a slag blending ratio of 30%, the preheating temperature was only 180; we compensated for this by using a higher oil ratio!
1. Increase the flow rate of the reprocessed oil into the mixer; since the temperature of this reprocessed oil is over 300 degrees, there will be sufficient heat available in the distillation section. 2. If you are not satisfied with the atomization effect of the feedstock, you can increase the mass flow rate of the atomization steam accordingly. 3. Set the regeneration temperature higher. The preheating temperature of the feedstock has little impact on the ratio of catalyst to oil; it only affects the atomization of the feedstock, ensuring proper fluidization and thus enabling control of the reaction temperature
Increase the temperature at which the slurry returns to the tower, and raise the slurry circulation rate