METHOD AND APPARATUS FOR USING EXCESS HEAT FROM POWER PLANT FLUE GAS TO DRY BIOMASS FUEL

摘要

The present invention relates to a method and device for drying biomass fuel using waste heat of flue gas from a power plant. The method comprises the steps of: 1) gradually using superheat from the flue gas; 2) a first stage high temperature hot air drying step; 3) drying of the two stages of constant hot air at an intermediate temperature; And 4) a drying step accelerated to three low temperatures. The apparatus comprises a multi-layer belt dryer (1) and an incremental heat-recovery and heat exchange system for superheating from the flue gas. The horizontal partitions 1-2 partition the conveying belts 1-1 in the drying chamber of the drying casing so that the sealed high temperature zone 2, the intermediate temperature zone 3 and the low temperature zone 4 respectively From top to bottom. A hot air inlet (5) is provided at the front end of the hot zone (2). An intermediate temperature air inlet 7 is provided at the front end of the intermediate temperature zone 3. At the front end of the low temperature zone (4), a low temperature air inlet (9) is provided. The discharge chute 1-3 is provided between the adjacent conveyance belts 1-1 so that the biomass fuel can be transferred from the upper layer to the lower layer along a serpentine path. The method and device allow the full utilization of the superheat from the flue gas, thereby achieving the goals of increasing drying efficiency, reducing energy and reducing emissions.