Catalytic hydroliquefaction of charcoal CCB (copper, chromium and boron)-treated wood for bio-oil production: Influence of CCB salts, residence time and catalysts

Thermochemical processes offer a feasible option for wood waste management and the recovery of a variety of useful chemicals. In this paper, hydroliquefaction with the use of catalysts was optimized to provide bio-oil from CCB-treated wood by reducing gaseous emissions of copper, chromium and boron (hazardous materials). In addition, the influence of CCB salts, catalysts (Al2O3, Na2CO3, MgO and CaCO3) and residence time on the hydroliquefaction process was investigated. For this, hydroliquefaction of charcoal obtained by slow pyrolysis of CCB-treated wood was conducted under hydrogen pressure in presence of tetralin. The results showed that CCB salts and catalysts increase the yield of bio-oil compared to hydroliquefaction of charcoal from untreated wood. It was also observed, that the use of catalysts improves the residence time during the process. Among the catalysts employed, Al2O3 appears to be the most effective. Furthermore Na2CO3 promotes the formation of gaseous species particularly CH4. Analyses of hazardous materials in charcoal residue (coke) illustrate their transfer to the bio-oil with the increase of bio-oil yield and residence time except when Al2O3 was using. The bio-oil obtained contains aromatic compounds.