Why remove hydrogen sulfide?

Biogas produced in anaerobic digesters typically includes concentrations of hydrogen sulfide from 40 to 4000 parts per million. Even greater concentrations have been observed. You will realize important benefits by removing hydrogen sulfide from your digester gas stream.

• Hydrogen sulfide reacts in gas processing equipment to produce sulfuric acid, a very damaging corrosive.
• Eliminating hydrogen sulfide from digester gas fueling internal combustion engines will extend engine life by reducing lubricating oil contaminants, particularly sulfuric acid.
• Boilers and other gas processing equipment will also benefit from the elimination of sulfuric acid derived from hydrogen sulfide.
• Eliminating hydrogen sulfide in the digester gas stream diminishes pollution and acid rain by reducing the formation of sulfur dioxide.
• Plant safety can be enhanced by curtailing personnel exposure to hydrogen sulfide; irritating at 5 ppm, toxic at 50 ppm, and deadly at 700 ppm.

Sulfide removal process

Time-proven, the “Iron Sponge gas sweetening process” has been “sweetening sour gas” in sulfur-bearing gas fields for over fifty years. This is the most effective method of removing hydrogen sulfide from a gas stream. Digester gas passes through the permeable bed containing hydrated ferric oxide. Hydrogen sulfide reacts with ferric oxide, as demonstrated by the following equation, forming water and black, solid, ferric sulfide.

A Marcab Gas Purifier will remove all hydrogen sulfide present in gas passed through the vessel. Marcab systems are passive; requiring no operator nor any mechanical or electrical power.