The invention relates to a constant volume type
clean coal combustion device. The constant volume type
clean coal combustion device mainly comprises a furnace inner wall, a furnace grate and a spring, wherein a cavity of the furnace inner wall is divided into an upper part and a lower part by the furnace grate, a pressure equalizing chamber is formed in the cavity below the furnace grate, a
coal fired layer and a
combustion chamber are arranged and formed in the cavity above the furnace grate from bottom to top, the bottom surface of the
combustion chamber coincides with the top surface of the
coal fired layer, the elastic coefficient of the spring is the product of the spontaneous stacking density of
coal and the top surface area of the
coal fired layer, the vertical central axis of the furnace grate is collinear with the central axis of the spring, the horizontal clearance between the side wall of the furnace grate and the side wall of the furnace inner wall is less than one half of the thickness of the furnace grate, in a coal
combustion process, the furnace grate is lifted by the spring and moves upwards together with the
coal fired layer, and the position of the top surface of the
coal fired layer is relatively fixed. The constant volume type
clean coal combustion device can be used by an
industrial furnace, an industrial boiler or a rural coal fired stove which burns low ash coal, clean coal or
biomass fuel. The constant volume type clean coal combustion device has the advantages of simple structure and low investment, the combustion efficiency is greater than 95%, the energy saving rate reaches 5% to 15%, and the emission of
flue gas pollutants is lower than the comprehensive emission level of
air pollutants.