Process Simulation and Analysis of Main Fractionator of Catalytic Cracking Unit

The process characteristics, structural characteristics and operation status of the fractionation tower:

1. Process characteristics The process characteristics of the catalytic cracking main fractionator are its feed composition and state. The feed of the tower comes directly from the catalytic cracking reactor, which includes dry gas (H2, C1, C2 hydrocarbons and a small amount of N2, CO, CO2, H2S, etc.), liquefied gas (C3, C4 hydrocarbons), gasoline, diesel oil, circulating oil And oil slurries, in addition, contain catalyst powder with coke attached. These reaction products are separated by fractionation columns.

2. Structural features The diameter of the catalytic cracking main fractionation tower is 318m, with a total of 37 trays. The upper part of the fractionation tower is equipped with 30 layers of solid tongue-shaped trays, and the separation function is completely in this section. The advantages of using solid tongue trays are that the processing capacity is large, the liquid level gradient is small, the liquid layer is low, and the pressure drop of the tray is small, which is beneficial to increase the inlet pressure of the rich gas compressor, reduce the compression ratio, and save energy.

3. Status of operation At present, the main fractionation tower of catalytic cracking is operating normally, but the main problem is that the Enstler distillation point between crude gasoline and light diesel oil is unclear, and the temperature overlap is 20-25℃, which needs to be improved.