Effect of gaseous agents on co-combustion characteristics of sewage sludge and coal

Co-combustion of sewage sludge and coal is a feasible way to seek energy and reduce environmental pollution. Oxy-fuel combustion is considered as an advanced technology to raise energy efficiency and improve CO2 capture in power plants. Thermochemical characteristics during co-combustion of sewage sludge and anthracite coal in air and oxy-fuel atmosphere were investigated via thermogravimetric analysis method. The cocombustion experiment was prepared into four mixing ratios at different heating rates in air and O-2/CO2 atmosphere with 21% and 30% oxygen concentrations. The results showed that the ignition and burnout performance of anthracite coal could be improved by addition of sewage sludge. The comprehensive property index of blends at heating rate of 50 degrees C/min were nearly 3 times more than those at heating rate of 20 degrees C/min. The lower burnout temperature and elevated ignition temperature, maximum mass loss rate, comprehensive property index, and activation energy samples can be observed in 21%O-2/79%CO2 atmosphere when compared with air atmosphere. With increasing oxygen concentration from 21% to 30%, ignition temperature and burnout temperature of samples were decreased, while maximum mass loss rate and comprehensive property index were increased. The activation energies of samples at heating rate of 20 degrees C/min were decreased, but increased at heating rate of 50 degrees C/min. These findings can provide new insights for further investigation on co-combustion of coal and sewage sludge.