At present

it is recognized as the most promising way to dispose municipal sludge by co-firing it in thermal power plants. By taking two subcritical 300 MW unit coal-fired boilers with tangential firing as the research object

the co-incineration test of sludge and coal mixture was carried out

so as to investigate the variation of furnace temperature

boiler efficiency and NOx emission mass concentration under conditions with different unit loads and mixing proportions of sludge. The experimental results show that

with an increase in mixing proportion of the sludge

the furnace temperature decreased

the mass concentration of NOx emission increased

while the change of boiler efficiency was not significant as the mixing proportion of sludge is below 10%.