Is there a relationship between the speed of the catalytic cracking compressor and backflow? Does reducing the speed increase the inlet flow, which helps prevent surge?
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Is there a relationship between the speed of the catalytic cracking compressor and backflow? Does reducing the speed increase the inlet flow, which helps prevent surge?
It doesn’t matter much; a lower inlet flow rate combined with reduced speed helps prevent stalling
The three methods for controlling reaction pressure are the speed of the air compressor, backflow, and flareing ； As backflow increases, the reaction pressure rises, and it becomes necessary to increase the speed of the compressor in order to control this backpressure. The speed of the compressor is adjusted based on the reaction pressure; the inlet flow rate of the compressor is merely an intermediate factor. Even if the inlet volume increases due to changes in composition, the reaction pressure does not necessarily rise. Reducing the rotational speed lowers the compression ratio and increases the inlet volume, which helps to shift the anti-surge line to the right and reduce surge
Increasing the anti-surge setting can raise the amount of rich gas returned, thereby increasing the reaction pressure. However, doing so wastes some of the turbine’s energy; therefore, when there is sufficient amount of rich gas at the inlet, it is better not to use the anti-surge feature in order to reduce energy consumption. If the amount of rich gas is low and there is a risk of surge in the compressor, then the anti-surge setting can be increased to boost the flow rate of rich gas at the compressor inlet.
The inlet flow rate of the compressor is related to the reaction temperature, backflow momentum, and rich gas temperature. If the DV value of the compressor permits it, the speed can be reduced to lower energy consumption. Now the pressure compressor is under automatic optimization control.