Smoke circulation type reciprocating grate combustion biomass steam boiler

A flue gas circulation type reciprocating grate biomass-fired steam boiler relates to the technical field of biomass-fired boilers and comprises a boiler body, a hearth is arranged in the boiler body and connected with an exhaust passage, a reciprocating grate used for conveying biomass fuel is arranged in the hearth, and the exhaust passage is connected with the reciprocating grate. A first air preheater and a second air preheater are arranged on the exhaust channel, and air is introduced through the primary air channel, preheated through the first air preheater and then sent to the reciprocating grate to promote combustion of biomass fuel. Air is introduced by arranging a secondary air duct, is preheated by a second air preheater and then is fed into the hearth to disturb high-temperature flue gas. According to the invention, insufficient combustion of biomass fuel can be avoided, and the pollutant content of discharged tail gas is reduced. 烟气循环式往复炉排燃生物质蒸汽锅炉，涉及燃生物质锅炉技术领域，其包括锅炉本体，所述锅炉本体内设置有炉膛且炉膛连接有排气通道，所述炉膛内