Adsorptive hydrogen chloride and combined hydrogen chloride-hydrogen sulphide removal from biogas for solid oxide fuel cell application

In order to reduce the toxic effect on solid oxide fuel cells performance caused by biogas contaminated with hydrogen chloride and hydrogen sulphide, the purification of biogas is essential. Adsorptive gas purification is a highly auspicious technology to provide pollution-free biogas for solid oxide fuel cell-based power units. In this work the authors examined the influence of different parameters onto the adsorption capacity of three commercially available sorbents. Experimental runs in a laboratory glass downflow fixed-bed reactor were carried out to analyse the adsorption capacity of a potassium carbonate impregnated activated carbon and two sorbents based on a mixture of aluminium oxide and silicon dioxide. Hydrogen chloride removal was accomplished with the impregnated activated carbon and metal oxide-based sorbents. Hydrogen chloride adsorption capacity was analysed under space velocities 8000 and 16,000 h(-1). In addition, the effect of a hydrogen chloride inlet concentration of 100 and 1000 ppmv was investigated. Furthermore, pellets in the size of 3-4 mm in diameter were crushed into a fraction between 500 and 1000 mu m to investigate the influence of particle size on hydrogen chloride adsorption capacity. Additionally, the combined adsorption of hydrogen chloride and hydrogen sulphide was realized using the impregnated activated carbon. The experimental runs and the results obtained in this work provide useful data for designing an adsorption reactor to clean up biogas and optimizing the process.