In order to investigate the effect of microwave upgrading on combustion characteristics of lignite

the high-water content lignite was microwave upgraded

and pilot-scale combustion characteristics of the upgraded coal at different coal feeding rates were compared. Lignite has been treated by tunnel microwave irradiation system for 25 minutes. The composition of coal

calorific value

ash composition

ash melting point and microscopic surface morphology before and after microwave upgrading were analyzed. On this basis

the 1 MW horizontal cylindrical furnace for thermal test at Zhejiang University was used for the pilot-scale combustion experiment. Then the temperature distribution

ash characteristics and pollutant emissions of the upgraded coal were analyzed. The results show that

after microwave upgrading

the water content of the upgraded lignite decreases

the calorific value increases

the surface becomes loose

and the specific surface area increases. In addition

the upgraded ignite is easier to be ignited

form molten slag and burn out. Moreover

the concentration of SO_2 emission has no obvious change before and after the microwave upgrading

while the concentration of CO emission increases and the concentration of NO_x emission decreases obviously.