Question

Explain in details:

1) In the crude distilation unit, the pressure is kept above atmospheric pressure slightly above atmosphere, and the temperature kept at 400 C , and give reason why it should not exceed 400 C ?

2) Give two examples of heavy distillates in Refinery?

Answer 1

1. The major reason to not have atmospheric distillation at temperature above 400 C is to prevent decomposition and to avoid thermal cracking of hydrocarbon. Also at higher temperature coke formation will take place this will cause deposition of coke particle at the bottom of the distillation column. This will result in chocking of the crud tower and will cause operational difficulty

2 Heavy distillates includes lubricants, wax , different grades of paraffin and asphalt