Catalytic Thermal Treatment (Catalytic Thermolysis) of a Biodigester Effluent of an Alcohol Distillery Plant

The catalytic thermal treatment (catalytic thermolysis) of biodigester effluent from an alcohol distillery unit was studied in the presence of CuO catalyst in batch mode in the temperature range of 100−140 °C and the pressure range of 1−9 bar. The catalyst mass loading, Cw, was varied between 2 and 5 kg/m3. Thermal treatment at 140 °C with a Cw of 3 kg/m3 gave a maximum chemical oxygen demand (COD) reduction of about 70% from its initial value of 34 kg/m3. The biochemical oxygen demand reduction was found to be 83% from its initial value of 6.3 kg/m3. The COD reduction−time profiles show two clearly distinct steps:  a fast process followed by a slower process. A good amount of charred solid residue is obtained, which is enriched with carbon, giving a C/H atomic ratio of 1:0.947, versus a C/H atomic ratio of 1:1.146 for the effluent. The charred residue is a good fuel material with a high heating value (∼17.92 MJ/kg) representing 42−47% energy recovery from the digester effluent. During the thermolysis, co...