First gas scrubbing stage - for gasification under pressure uses tar made viscous by tar oil addition for injection

摘要

The parent patent describes gas produced by coal gasification under pressure is passed through a heat exchanger where high-boiling tar oil is sprayed to prevent incrustations. H2S is absorbed by injection of an alkaline or alkaline earth powder in a venturi stage. In this addn. the gases are passed through a pre-scrubber, using tar with slight additions of tar oil to keep it viscous. The powder for the H2S absorption is now injected after the wash oil process has been completed. This combines some of the wash tar with the tar in the crude gas and improves the heat balance. The tar spraying in the scrubbing tank prevents incrustations. The heat recovery from the tar wash circuit saves the necessity for a gas precooler.