Membrane water-wall compound return water condensing type natural gas hot water boiler

Disclosed is a membrane water-wall compound return water condensing type natural gas hot water boiler. The natural gas hot water boiler is characterized in that a gas collector is connected with a primary pipe network water supply pipe (21) in pipelines; return water of a primary pipe network return water pipe (20) in the pipelines sequentially passes a lower water header, a lower header, a first heat exchanging pipe, an upper header and an upper water header of an economizer and a rear-membrane type water wall, a mid-partition membrane type water wall, a left-membrane type water wall, a front-membrane type water wall and a convection bank of a hearth (5) to be finally converged in an upper boiler barrel; the pipelines further include a secondary network water return pipe (22) and a secondary pipe network water supply pipe (23), and return water of the secondary pipe network return water pipe sequentially passes a branched water header (31), a second heat exchanging pipe (32) and a water header (33) of a condenser; one end of the water header is connected with the secondary pipe network water supply pipe while the other end is plugged. The membrane water-wall compound return water condensing type natural gas hot water boiler has certain universality, heat utilization rate of the boiler is increased, fuel cost during operation is lowered, and service life of boiler equipment is prolonged.