Taking a bituminous coal fired 350 MW unit boiler as the object

experiment of co-combustion with different proportions of lignite premixed on coal convey belt was conducted.The safety

economy and environmental protection characteristic of the pulverizing and combustion system under different blending proportion of lignite conditions were investigated.The results showed that

after co-firing with the Zha coal

drying capacity that the pulverizing system needed increased dramatically

and the blending proportion of Zha coal should not be larger than 50% for each boiler.With an increase in the Zha coal proportion

the reheat steam temperature rose obviously

the exhaust temperature and ash combustible content increased

and the boiler efficiency dropped.When the proportion of Zha coal reached 3/8

the NOx emission dropped by about 24.7%.When co-firing the Zha coal with Dayou coal

proportion of less than 3/8 will not aggravate the slagging occurred in burner area and high temperature convective heating surface area.