Pyrolysis/gasification of pine sawdust biomass briquettes under carbon dioxide atmosphere: Study on carbon dioxide reduction (utilization) and biochar briquettes physicochemical properties.

In this paper, the effects of temperature and CO2 content on CO2 reduction (utilization) efficiency and physicochemical properties of pyrolysis/gasification biochar briquettes were investigated. The CO2 reduction (utilization) efficiency (CRE) reached the peak value of 74.9% in a 10% CO2/90% N2 atmosphere at 600 °C. The crackings of hydroxyl, CC bonds, methyl and methylene groups of biochars briquette were enhanced by high temperature and CO2. The increase of CO2 concentration was beneficial for developing biochar microporosity, but not conductive to enhance higher heating value, volume density and durability of biochar briquette. To get a higher CRE and make feasible biochar briquettes are the primary goal for this work. Therefore, the optimal introduced CO2 to biomass ratio is calculated to be 135 g/kg for experiments done with 10% CO2 with N2 at 600 °C.