Engineering Application and Evaluation of Lignite Drum-type Drying Technology with High Temperature Flue Gas

According to the coal analysis,as the wet basis,the total moisture content of lignite dried was decreased from 41.3% to 13.9%,and net calorific value was increased from 13.40MJ/kg up to 21.05MJ/kg.Consequently the effect of lignite dehydration and quality improving is apparent.The net calorific value of the pulverized coal collected by the coal powder collector was 16.00MJ/kg,which is lower than the design value of 20.93MJ/kg.One reason for explaining this is that the fixed carbon content significantly reduced.Appropriately adjusting the ratio of fine-grained powder is suggested to shorten the cold starting time.According to the analysis on long starting time,which is induced by the characteristic that system combustion load is coupled to the drying capacity,and the oxygen content in low load conditions is never less than 10%,the advice is put forward.Checking calculations show that the designed heat release rate of hot flue gas furnace is greater than the recommended value,and reasonable expansion of the furnace structure is provided so as to achieve the full load in safe.