Biogas Purification

Biogas is a renewable resource that can be obtained from the anaerobic digestion of organic waste such as sewage, animal or food waste, agricultural waste and the organic fraction of municipal solid waste. The usual contaminants in biogas are hydrogen sulfide and sulfur compounds and siloxanes, molecules containing silica bound to oxygen and halogens. Activated carbon has a highly developed pore structure that provides numerous adsorption sites for gas molecules. Chemically modified activated carbon can further enhance its ability to adsorb harmful gases such as hydrogen sulfide and ammonia, effectively removing pollutants from biogas.

Conventional Activated Carbon

This type of activated carbon primarily removes harmful gases such as hydrogen sulfide by physical adsorption. Hydrogen sulfide molecules adsorb through the microporous structure of the activated carbon and physically interact with the carbon surface to effectively separate the hydrogen sulfide.

The most common types of activated carbon are:

• 4 mm pellet activated carbon CTC60designed for air and gas purification applications and produced by high temperature steam activation of bituminous carbon. The result is a porous material with a large surface area capable of adsorbing a wide range of impurities and harmful gases such as hydrogen sulfide.
• Granular activated carbon 4×10Due to its unique pore structure, it provides a large contact surface with the gas, which improves the adsorption efficiency of various impurities.

Impregnated Activated Carbon

In biogas purification, impregnated activated carbon, such as potassium hydroxide impregnated activated carbon and potassium iodide impregnated activated carbon, is often used.

This particular type of activated carbon improves its adsorption properties by mixing or impregnating the carbon with certain chemicals (impregnants). This treatment significantly increases the capacity of the activated carbon to adsorb specific pollutants and effectively remove harmful substances from the biogas.

The relevant parameters are as follows: