The invention discloses a reverse burning multi-return-
stroke biomass low-carbon energy-saving steam boiler. The steam boiler consists of a multi-return-
stroke flame tube (1), a water sleeve (2), a return
stroke flame outlet (3), a return stroke
flame inlet (4), an ellipsoidal seal head (5), a
biomass charging opening (6), a
biomass semi-gasification
hearth (7), a grate (8), a secondary
combustion chamber (9) and a reverse burning channel (10). In the reverse burning multi-return-stroke biomass low-carbon energy-saving steam boiler, fuels are gasified in advance in the biomass semi-gasified
hearth under the action of an induced draft fan, and a large number of
volatiles are separated out in the gasification process; the fuels are fully combusted under the action of secondary wind; flame enters the flame tube and then the return-stroke flame outlet from bottom to top along the
combustion of the fuels; the fuels are returned from the return-stroke flame inlet downwards from top to bottom; therefore, a reverse burning multi-return stroke is formed. The reverse burning multi-return-stroke biomass low-carbon energy-saving steam boiler is made of any one of iron and stainless steel. The boiler makes
combustion sufficient, is low-carbon and energy-saving, makes waste profitable, realizes resource regeneration, purifies the environment and is beneficial to the nation and the people.