| Summary: | When plant refuse burning process of drying of fuel is transferred to the furnace camera. Drying of large particles of fuel from the very beginning proceeds in the period of the drooping combustion rate. At the same time the front of evaporation goes deep in material, volatile components and coke residual are separated and firing. In the conditions of convective and radiant heat exchange with the combustion gases which are in case of high temperature, the particle practically at once gets warm to a water boiling temperature. At the same time process of intensive evaporation of moisture which front moves deep into material begins. «Dry» and «wet» zones are formed in a particle. Warming up, separation of volatile components and their inflaming in «dry» zone begin in the course of a deepening of evaporation zone. Three periods of drying are provided for burning of a large particle of the wet fuel with a radius more than 1 mm: before inflaming of volatile components; visible burning of volatile components before inflaming of coke on a surface; the drying proceeding in parallel with coke burning-off. A certain location of an evaporation zone corresponds to each of these periods. And we can calculate particle dryness and drying duration. Summary time of drying represents duration of particle ignition. Processes of particles drying and ignition with different initial humidity and under various conditions of a heat emission were calculated. Drying, separation and inflaming of volatile components, as well as burning of coke residual take place at the same time in a large wet particle of plant refuse in case of arrival into the furnace camera. Duration of ignition is defined by end time of burning of coke residual and can be calculated according to complete drying of a particle. In the furnace unit TBR-2.0 drying and ignition of the wet soft plant refuse particles with a radius less than 0.25 mm takes less than for 2 s, drying with the subsequent ignition of particles with a radius of 1-3 mm continues 30 s.
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