Syngas Production from Biomass Pellets in a Downdraft Gasifier and the Removal of Oxygen from Syngas

In pellet production, the parameters, such as densification pressure, temperature, feed moisture content, and coal and biomass concentration, that affected pelletizing and pellet quality were investigated. Gasification was carried out in a downdraft gasifier by using red oak hard wood as the feedstock. The raw syngas primarily contained carbon monoxide (CO), hydrogen (H2), carbon dioxide (CO2), methane (CH4), and nitrogen (N2) as well as contaminants such as ash, water vapor, ammonia, and oxygen. Ash was removed with the filter bag. Water vapor was removed by desiccant absorption. Ammonia was removed by water scrubbing. Oxygen was removed by a CuO/CeO2-Al2O3 catalyst in a fixed-bed tubular reactor from 1% to less than 1ppm. After cleaning, the syngas was compressed up to 2000 psig pressure. The clean syngas was readily used for the Fischer-Tropsch catalytic reaction