ICOPE-15-C083 Study of Numerical Simulation and Field Test for Co-Combustion of Sewage Sludge on a 100 MW Coal Fired Boiler

Abstract

A series of field test and numerical simulations was carried out to evaluate the characteristics of coal combustion and coal combined firing with sewage sludge in a 100 MW tangentially coal fired utility boiler. The simulation results was highly consistent with the experimental data when the moisture content of sewage sludge was 56% with mass blending ratio less than 10%: the flue gas temperature decreased, char burnout rate fell, unburned carbon in fly ash and NOx emissions, but the differences were small. Both the experimental and simulation results indicated that small mass ratio of sewage sludge co-combustion has little effect on the operation of boiler. Additionally, the influence of combustion characteristics and pollutant emissions when co-combustion high blending ratio of sewage sludge was further studied. Results showed that the decrease of sewage sludge moisture content was helpful in improvement of the boiler combustion characteristics, besides, the NOx emission also reduced. The NOx emission increases and the flue gas temperature and the burnout rate of char decreases when increasing the sewage sludge blending ratio up to 30%. And the changes become more and more significant. In addition, the NOx reduction strategy and the slagging tendency caused by the co-combustion of sewage sludge were also studied.