Reduce the vapor load at the top of the catalytic fractionation tower to save energy and reduce consumption
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By changing the catalyst type, the catalytic reaction becomes more intense, resulting in a higher gas load on the distillation column; therefore, the top temperature needs to be controlled using cold reflux. Is there a good way to shut off the cold reflux completely and remove the excess heat without salt forming at the top of the tower?
Increase the reflux at the middle section and at the bottom of the tower, thereby enhancing heat removal from those areas.
Increase the return flow of the top circulation as well as the return flow and heat extraction at each intermediate stage. Reduce the circulating water temperature to ensure that the temperature of each heat exchanger after cooling remains within the lower limit range. Increase the heat uptake of the low-temperature hot water system. If the above adjustments are not possible, cold reflux must be enabled.
Won’t it cause the light components to be pressed down?
It shouldn’t fail to drop. What’s the temperature difference between the exhaust from the top circulation system and the return flow to the tower right now? If the temperature difference is small, it means there’s a problem with the heat exchanger in the top circulation system. My facility encountered this issue some time ago
The catalyst has been changed, from FCC to DCC; there is much more gas now than before
Is changing FCC to DCC just a solution by replacing the catalyst? Were no other corresponding devices replaced? Is this reasonable?
The load on the units is generally designed to be much higher; as long as it’s not excessively high, there should be no problem. For example, many of our previous vacuum distillation units were designed for fuel oil, with a naphtha yield of around 10%. With the liberalization of imported crude oil, the properties of the oil have become lighter, allowing the naphtha yield to reach 20%. However, if it goes any higher, the tower top cooling system can’t handle it, so it’s necessary to reduce the production volume
Although they are all technologies under the category of catalytic cracking, since the main products of DCC are primarily gas-phase products, the requirements for equipment are much higher, especially for the pressure units and the coolers after the fractionation tower! In conventional catalytic cracking, there are usually 8 sets of 16 coolers after the distillation tower, while the DCC process requires 12 sets of 24 coolers. If the equipment cannot keep up, can the plant handle the load?
Is the gas yield of the DCC process around 30%?
The data from the material balance sheet of a certain set of DCC devices!