Concept Design of the WRB-6 Water-Tube Boiler with a Stepped Grate and a Furnace for Burning Straw Bales in a Cigar System

The article presents the conceptual design of the solid fuel from the forest and sawmill production waste and agricultural waste biomass-fired water boiler. The project was supported by thermal and flow calculations. The designed WRB-6 boiler is a 3-pass unit with a fully screened furnace chamber and is equipment of a local biomass heating plant. It is fired with biomass, transported over no more than 30 km. The furnace has a double function–dual fuel. Both fuels can be burned simultaneously or alternately, depending on seasonal availability. In the front part there is a channel for feeding and burning large bales of cereal straw. The lower closure of the chamber is a mechanically inclined grate for the combustion of wood biomass in the granulation of chips. As part of the work, calculations of the amount of biomass fuels possible to be obtained on the local market with economy of delivery were also performed. As a result of the calculations, the temperatures of water and flue gas at the outlet, boiler efficiency, slagging and impurity indices for biomass were also presented.