Efficiency of fuel drying to increase heat production

The article deals with the issue of increasing the efficiency of fluidized bed boilers when burning high-humidity brown coal. Eighty tons of coal per hour will be burned in the boilers. Drying of coal is alternatively required to 25 or 10% moisture. Four solutions were considered in the solution, from which two variants were developed. The first variant was a drying in a fluid drier and the second variant was a tumble drier drying, including a technical design of the dryer equipment. In both cases, 300 ° C steam and pressure 1 MPa are used for drying. There are 40 tons of steam per hour. The drum dryer requires a substantially higher hourly amount of steam than fluidized. For a fluid dryer, we need about 360 tons of steam for one-time filling. In operation, it is necessary to supply about 40 tons of steam per hour, which can easily be covered by the operating needs of the heating plant steam. The dried fuel will increase its calorific value. The calorific value of the burned fuel was calculated for both variants of drying. These balances were made based on the results of the fuel drying tests in the fluid test apparatus. The article presents test results. On the basis of technical-economic evaluation of the drying of the fuel it was recommended to carry out the drying in the fluid dryer by the WTA method.