Scheme of incineration of wood waste in a furnace with a circulating boiling bed

Abstract

Cyclonic-vortex technology of solid fuel combustion allows to reduce the furnace volume of the boiler unit, dimensions and weight. Mixing of fuel particles and air in a swirling stream provides intensive heat exchange and fuel combustion in a limited furnace volume. The results of improving the thermal scheme of combustion of pulverized fuel (wood waste) in a circulating fluidized bed are presented. The results of numerical calculations showed the possibility of burning sawdust with a particle diameter of 25 μm to 750 μm. When the air-fuel mixture is supplied from the bottom of the furnace, and the secondary air from the top of the furnace, ash is removed in liquid form through a slot in the lower part of the furnace. It was found that with a sawdust moisture content of 10%, ash content Ac = 0.6%, a higher combustion heat of 17.7 MJ / kg, particle entrainment is 19.2 %, the degree of particle burnout is 92.5%, which requires afterburning of entrainment in a circulating boiling layer. One of the ways to improve Ukraine's fuel and energy balance is to use alternative sources of heat to natural gas, namely solid fuels or wood industry waste. It is necessary to involve specialized technologies for burning solid fuels. Currently, there is an incomplete theoretical and practical knowledge about the processes of burning wood waste.The use of natural gas as a source of thermal energy occupies a significant part of Ukraine's fuel and energy balance. To increase the share of solid fuels, it is necessary to study in more detail the processes of their combustion and the use of methods of intensification of heat transfer processes in the furnaces of solid fuel boilers. The results of numerical calculations showed that the use of vortex furnace instead of direct flow in the scheme CKS increases the residence time of particles in the furnace, which reduces the multiplicity of fuel circulation, reduce the size and weight of the furnace