The main heating surface of the coal-fired steam boiler is in the shell, with less air leakage; and the furnace wall is tight and the heat preservation performance is good. The coal fired boilers feature has obvious, the threaded smoke tube does not accumulate dust, has a high heat transfer coefficient, and the boiler has high efficiency. Due to the use of natural circulation and jet forced circulation, the water resistance loss of the boiler body is small, which greatly reduces the cycle energy consumption of the system, improves the thermal efficiency of the boiler, and saves power consumption at the same time.
The boiler uses a high-efficiency heat transfer threaded smoke tube, and the flue gas is transformed from laminar flow to turbulent flow, breaking the boundary layer. The actual output of the boiler can generally exceed the output of the nameplate by 10-15%. This series of coal-fired boilers has a reasonable choice of smoke speed and no dust accumulation in the threaded smoke tube, so the boiler output and thermal efficiency will not decrease with the extension of the operating time. The total weight of boiler steel and heat-resistant and heat-insulating materials is less than that of other boilers, and a large number of high-efficiency heat transfer threaded smoke tubes are placed in the shell medium, and nearly half of the shell surface is heated. The heating time is about 1/3 shorter than that of water-tube boilers.
The coal fired boilers feature has outstanding and adopts a convection tube bundle structure to reduce the temperature of the flue gas entering the front tube sheet to below 700°C. Moreover, the thermal stress of the arched tube sheet is small, and the end of the threaded smoke tube is flush with the welding seam, and the tube sheet is expanded and then welded to eliminate the gap between the tube and the tube hole. And part of the boiler backwater flushes and cools the front tube plate. The above measures can effectively prevent the tube sheet from cracking and ensure the safe and reliable work of the tube sheet.
Ascending pipes are arranged on the left and right sides of the coal-fired steam boiler, and an injection device added to the bottom of the drum by the boiler return water. Make the water disturb the bottom of the drum, the water at the bottom of the drum has no dead zone, does not produce supercooled boiling, and the sludge is not easy to deposit. In addition, the distance between the lower part of the shell and the fire bed is relatively large, so that the drum bulge is not generated. The return water of the boiler is added with a jet to prevent the phenomenon of super-cooling and boiling. At the same time, a part of the return water is injected to the front of the drum to flush the front tube plate, reducing the temperature of the front tube plate and improving the safety of the tube plate. A throttling ring is set at the entrance of the rear wall pipe to force most of the water to flow into the rear arch pipe, increase the water speed of the rear arch pipe, ensure the safety of water circulation in the rear arch pipe, and prevent supercooling and boiling.
This series of boiler products adopt high-efficiency and energy-saving furnace arches and segmented gas supply, the slag carbon content does not exceed 14%, and the fuel is completely burned. Coal fired boilers feature have obvious, using natural circulation and forced injection circulation. If there is a sudden power failure, no special protective measures are required to prevent damage accidents caused by the possible vaporization of the heating surface and the medium in the housing. Due to the large furnace volume, the dust separation turning chamber between the boiler outlet smoke window and the convection tube bundle inlet is relatively thick, which can ensure that the original dust concentration of the boiler is 20% lower than the standard allowable value. % To 30%.