Dahlman OLGA

Gas purification overview

Treatment of gasification gas is depending on

1. The feedstock and its chemical composition 
2. The gasification technology and the operational conditions of the gasifier 
3. Downstream equipment and the application; how clean should the gas be?

In general we can identify the following gas treatment steps. The necessary steps and their logical order are the basis of important choices in the process engineering phase.

• Particulate removal cyclones, filters, electrostatic filters, scrubbers
• Removal of organic impurities (tar), OLGA is the main topic of this website
  (see OLGA vs. other systems for an overview of technologies)
• Removal of inorganic impurities
  -  Conversion of COS to H₂S and HCN to NH₃ by hydrolysis
  -  Removal of nitrogen and halogens (mainly NH₃ & HCl), by aqueous absorption scrubbers
  -  Sulphur removal (H₂S) by absorption and possibly conversion to elementary sulphur
• Removal of volatile (alkali) metals, by pre-coat filtration