Why are two columns installed in the depropanization tower?
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Why are high-pressure and low-pressure columns required in the pre-depropanization process? Could you explain it item by item?
A single tower that is too tall, standing alone, is inconvenient; having towers of similar height makes it easier to set up a combined platform.
In the previous depropanization process, if only a high-pressure depropanization column was used, the column design would have to be quite tall; moreover, at high pressures, components such as dienes and pentadienes, which tend to coking, could cause blockages in the heat exchangers due to high temperatures, resulting in poor heat exchange efficiency and making long-term operation difficult. Secondly, if only a low-pressure depropanization column is used, lowering the pressure will inevitably increase the amount of refrigerant consumed, thereby raising energy consumption. Therefore, by using both high- and low-pressure depropanization columns, coking in the reboiler can be effectively reduced, as well as the amount of refrigerant required at the top of the column.