Clean gas, long engine life.

Overview

Biogas and landfill gas always contain hydrogen sulphide. It is usually in the range of 1,000 to 6,000 ppm but may reach 2% by volume, 20,000 ppm, or more. Ammonia and silicone compounds add to the problem. All three attack engines, boilers and catalysts and must be reduced before the gas is used.

Activated carbon

For smaller contamination levels, or as a final polishing stage, the gas is routed through a bed of activated carbon. Contaminants and impurities are exposed to the filter media and captured through the adsorption process. Renew sizes vessels and carbon grades to the specific contaminant profile from your gas analysis, and supplies replacement media.

Biological gas purification

Where hydrogen sulphide levels are high, biological desulphurisation is the preferred non-chemical approach. A limited amount of air, 10 to 15% relative to the gas throughput, is injected into the process. Bacteria of the genus Thiobacillus convert the H₂S to elemental sulphur and sulphuric acid, which are drained away with the condensate.

The bacteria need three things to thrive: oxygen, added nutrients and trace elements, and a surface to grow on. Renew provides all three, either inside the gas holder using sulphur-removal netting or in a dedicated external scrubber column.