Activated carbon is used as an adsorbent from LESNI for more than 33 years for various contaminants for air purification. It is in operation e.g. for VOC’s, inorganic carbon compounds and odors to reduce concentration to required levels – legal legislations - but also for recovery of some substances. These adsorbers are used for different applications, such as production processes and manufacturing operations to control emissions, odor abatement in sewage treatment plants (STP) just as well treatment of sewage- and biogas.
Biogas is produced by the digestion process of biological substrates, such as cattle and pig manure, corn silage etc. By burning biogas in a block heat and power plant you turn it into electrical power and thermal energy. Unfortunately some unwanted by-products accrue, e.g. hydrogen sulphide (H2S). Hydrogen sulphide reacts in the first step while burning to sulphur dioxide and water. Secondly with pressure and heat it develops to sulfurous acid (H2SO3), which has a negative, corrosive effect on the equipment. An almost complete desulfurization of biogas is necessary. LESNI high effective and cost saving technology by using an adsorber filled with special impregnated activated carbon, which removes the sulphur from biogas by chemical adsorption and helps to prevent damages at gas engines and to expand service interval and lifetime of equipment. The LESNI activated carbon filter is suitable to remove H2S from a few ppm up to over 1.000 ppm (several thousand ppm) with high purification efficiency.