The thermal efficiency of the SZL 4ton biomass boilers of all specifications is >82%, which is higher than the national standard requirements. After simplifying the water circulation circuit of this series of boiler products, the water circulation flow resistance is reduced and the flow velocity in the riser pipe is increased; for the left and right water walls of the hot water boiler with large water circulation flow resistance, a return water ejection device is installed. The SZL type 4 ton boiler improves the reliability of the water cycle and ensures the safe and stable operation of the boiler.
The biomass steam boiler is arranged with enough heating surface, so that the heat released by the fuel combustion can be fully absorbed by the heating surface and then transferred to the working medium, and the exhaust gas temperature is lower than 160 °C. This series of biomass boilers adopts a reasonable arrangement of front and rear arches to increase the furnace temperature and at the same time strengthen the disturbance of flue gas in the high temperature area, and reduce the loss of chemical incomplete combustion and fly ash loss. The use of large pieces of grate or scale-type grate, and to ensure that there is enough effective area of the grate, while improving the reliability of the grate operation, to ensure that the fuel is fully burned.
The 4ton biomass steam boiler adopts double-side air inlet, separate air chamber, and separate adjustment, which has stable combustion and reliable operation. The SZL type 4 ton boiler is equipped with a fume and dust inertia separation device at the furnace outlet, so that the original dust concentration of the boiler is lower than 1800mg/Nm³. This type of boiler can be equipped with high-efficiency multi-tube dust collector and bag filter, and the flue gas emission of the boiler meets the requirements of national first-class areas.
The SZL boiler is a double-drum longitudinally arranged water-tube chain boiler. The fuel falls into the front end of the grate from the front coal hopper, and then falls into the slag machine for discharge after combustion. The air from the blower enters the grate air chamber partition through the air ducts on both sides of the grate base, and enters the furnace through the fuel layer. The flue gas after fuel combustion passes through the furnace, the ember chamber, the convection tube bundle I, the convection tube bundle II, and the economizer in sequence, and then is discharged from the boiler.
The front wall and both side walls of this series of steam boilers are equipped with radiant heating surfaces, and 15 φ51×3 riser pipes are drawn from the front header to form the front wall water wall. The SZL biomass boiler consists of 100 φ51×3 riser pipes drawn from the headers on both sides to form the side wall water wall. Secondary air ducts are arranged under the front arch and the left and right side walls, and the secondary air converges in the middle of the furnace into a tangential circle.
Two groups of convection tube bundles I and II are arranged between the upper and lower drums of the SZL type 4 ton boiler. The pipe specification is φ51×3, the material is seamless steel pipe for No. 20 boiler, the tube bundles are arranged in series, the transverse pitch is S1=120mm, the longitudinal pitch S2=85mm, and there are 18 rows in the transverse direction and 21 and 14 rows in the longitudinal direction respectively. A cast iron economizer is arranged in the boiler, which can further reduce the exhaust gas temperature of the boiler. The flue gas temperature at the outlet of the economizer is lower than 170 ℃, and the length of the economizer pipe is 1500mm.