Biogas Desulfurization

Biogas is produced as a byproduct of anaerobic digestion or by decomposition of organic wastes into methane and carbon dioxide. Effective utilization of biogas in fuel cell applications requires the removal of impurities such as sulfur (e.g., hydrogen sulfide, mercaptans, and disulfides) and siloxanes to prevent degradation of cell stacks and poisoning of the catalysts used in the fuel processor. The sulfur concentration in biogas can be very high (up to 400 - 15,000 ppmv) and the gas is saturated with water (~5-8% vol. H₂O).

SulfaTrap™-R8 is formulated as a moisture tolerant sorbent; it can achieve high sulfur capacity not only for hydrogen sulfide (H₂S) but also for all mercaptans, organic di-sulfides and tri-sulfides. SulfaTrap™-R8 can reduce the sulfur concentration in the biogas to low ppbv levels in one step. Siloxanes are man-made organic compounds that contain silicon, oxygen and methyl groups used in personal hygiene, health-care and industrial products. At the wastewater treatment plants and landfills the low molecular weight siloxane species volatilize and contaminate the digester gas. SulfaTrap™-Si and modified SulfaTrap™-R8 sorbents remove siloxanes from biogas without applying any refrigeration or other complicated gas treatment processes.

FEATURES

• High selectivity
• High removal efficiency to all sulfur species
• Reducing sulfur concentration to less than 5 ppbv
• High capacity for all sulfur species
• Capacity for H₂S in excess of 20% wt.
• Capability of removing organic sulfur compounds (e.g. mercaptans & disulfides)
• Capability of simultaneously removing siloxanes
• Operates at high levels of moisture and CO₂
• Easy disposal
• No flammability, toxicity or pyrophorocity
• Expendable or regenerable operation