Biochar Production and Bio-oil Upgrading by Synergistic Catalytic Pyrolysis of Wastewater Biosolids and Industrial Wastes

Catalytic pyrolysis of wastewater biosolids was conducted using specific industrial-waste-derived catalysts to reduce crude bio-oil yield while increasing pyrolysis gas (py-gas) yield simultaneously. This was done because bio-oil can be difficult to handle, whereas py-gas is a desirable product that can be easily combusted for energy. A lab-scale pyrolyzer with a downstream catalyst bed was employed. Higher py-gas yields were obtained using B3 and B4 catalysts compared to B1 and B2 catalysts, especially at temperatures over 700°C. The py-gas yields increased compared to non-catalyzed control. Meanwhile, the bio-oil yield decreased dramatically. Hence, B3 and B4 catalysts can increase on-site energy recovery from py-gas. Also, the bio-oil optical properties were improved and the energetic py-gas constituent concentrations such as H2 increased. This catalytic process could be beneficial at water reclamation facilities because energy recovery from py-gas is less complicated. Moreover, this process can produce a clean, value-added soil conditioner called biochar.