What is the difference between a flash tower and a fractional distillation tower? Basis for selection?

The difference is that the pressure in the flash tower is lower than that in the primary distillation tower

The initial distillation tower is the flash tower; it shouldn’t be operated under increased pressure, right? Too high pressure can cause the tower top safety valve to open.

1. For ordinary crude oil, the initial distillation tower has greater capabilities and flexibility compared to the flash tower in terms of pre-dehydration, hydrogen sulfide removal, and preventing overpressure in the atmospheric distillation column； 2. However, from a process perspective, the initial distillation tower process is more complex and requires higher investment. However, if a light recovery unit is installed in the atmospheric and vacuum distillation unit, the compressor can be omitted, **reducing the total investment for the entire unit. 3. The light gasoline, which is the product from the initial distillation tower, is generally used as feed for catalytic reforming units. Due to the arsenic-containing organic substances in crude oil, which decompose and vaporize as the temperature of the crude oil rises, the arsenic content in the gasoline from the initial distillation column is low, whereas the arsenic content in the gasoline from the atmospheric distillation column is high. Arsenic is a harmful substance for reforming catalysts; therefore, crude oils with high arsenic content used to produce reforming feedstocks generally undergo treatment in a fractional distillation tower. 4. The initial distillation tower shares part of the processing load of the atmospheric tower, while the flash tower does not.

Generally, at a certain scale, atmospheric-pressure units can be equipped with a primary distillation tower. The crude product obtained from this tower has a better quality than that from the normal distillation column; side streams can also be extracted, which is beneficial for the processing of light oils. The vapor from the top of the flash tower is fed back to the upper part of the atmospheric-pressure tower as a vapor feed, which helps to increase the processing capacity and the thermal efficiency of the heating furnace

Reply to 4# wsm1988: My graduation project is about atmospheric and vacuum distillation, and I need to decide whether to use a flash tower or a primary distillation tower Can you analyze it?

Reply to 6# geqian000: What are the conditions?

Reply to 7# wsm1988: The processing volume for Daqing crude oil is 3 million tons

This post was last edited and replied to by wsm1988 on 2011-4-6 22:38. Reply 8# geqian000: It mainly depends on whether raw materials need to be reprocessed If it’s necessary, it’s best to use a primary distillation tower; a reforming flash tower isn’t required.

Reply to 9# wsm1988: It's needed! My reprocessing materials are used to produce gasoline, as well as liquefied gas and BTX

Reply to 10# geqian000: It’s best to use a primary distillation tower!