What should be the appropriate temperature control for the cooled rich gas in catalytic cracking?
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Please share your opinions: what should be the appropriate temperature after cooling of the rich gas in the catalytic cracking fractionation system? What are the effects of too low a temperature on the equipment?
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The rich gas component is too light, which can easily lead to vacuum formation in the compressor; generally, this occurs at temperatures between 35-40 degrees
We keep it at no more than 40°
Our target temperature after cooling is 35–45 degrees, but in practice it’s around 37–42 degrees. Such a low temperature increases energy consumption. As for evacuation, I don’t think that’s an issue; I remember that at the beginning of operations, the crude gasoline tank was filled with gas before starting up the system. Therefore, I don’t think a lower temperature will cause the compressor to become evacuated, unless it is low enough to condense all components above C3 and C4 in the rich gas. At higher temperatures, some of the slightly more complex components cannot condense and remain in the gas phase. It condenses at the inlet of the compressor. Therefore, the most direct phenomenon is a rapid rise in the liquid level of the degassing vessel at the compressor inlet. In severe cases, it may threaten the normal operation of the press. My humble opinion
1 Does “rich gas” refer to the oil and gas at the top of the distillation tower or the oil and gas at the outlet of the compressor? 2 Whether it is the oil and gas at the top of the fractionation tower or the oil and gas at the outlet of the compressor, it is generally required to be cooled to 40°C. If it’s too high, it affects downstream operations; if it’s too low, it may be difficult to achieve the desired result.
Water coolers are generally considered for installation at the outlet of air compressors, especially in the southern regions where they are even more necessary.