PROCESS STRATEGIES FOR ACID GAS ENRICHMENT

摘要

The sour gases produced in the amine treatment of natural gas and in the treatment of gas associated with the oil production are very often lean in H2S and contain impurities such as BTX (benzene, toluene, xylene), mercaptans, and hydrocarbons. In many cases, offgases containing disulphides and additional feedstocks rich in SO2 have also to be treated in sulphur recovery units to satisfy the requirements of the environmental authorities. A peculiarity of these treatments is the frequent fluctuations of the composition of the feedstock and in particular of the H2S content, with significant impacts on the stable operation of the sulphur recovery units. The concentration of H2S and the presence of certain impurities in the feedstocks to Claus units play a crucial role in the selection of the appropriate plant configuration. This paper describes process strategies for the treatment of very lean H2S feedstocks.