Fundamentals of Low‑Tonnage Sulfur Removal and Recovery

Solid Scavengers

For smaller scale removal requirements, such as from a few pounds to perhaps a few hundred pounds a day, adsorption and absorption on solids are one of the oldest approaches but still extensively used today. These are both once-through or throwaway processes as well as regenerative processes.

Liquid Scavengers

H₂S scavengers are chemicals that favorably react with H₂S gas to eliminate it and produce environmentally friendly products. These products depend on the type and composition of the scavenger and the conditions at which the reaction takes place.

Liquid Redox Process – LO-CAT®

This paper provides an overview and update on a category of processes that are used to remove H₂S from sour natural gas and other gas streams by converting it to solid elemental sulfur for sale or disposal. These processes have been termed “liquid redox” in the industry, referring to the reduction/oxidation reactions that occur in the liquid phase. These types of processes typically are applied to streams where the total amount of sulfur removed is less than 20 tons per day (TPD).

Biological Processes

Biological processes use an alkaline solution to remove H₂S from a feed gas stream and then converts the sulfide to elemental sulfur using bacteria as the catalyst. After widespread use in the landfill and digester markets, these processes were adapted to the gas processing industry.