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

Abstract

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.

Description

technical field [0001] The invention relates to a natural gas hot water boiler, in particular to a membrane type water wall composite return water condensing natural gas hot water boiler, which belongs to the technical field of deep recovery of boiler heat. Background technique [0002] Coal-fired hot water boilers are usually used for heating in winter. However, due to the small steam capacity of coal-fired hot water boilers, the discharge of pollutants from boilers is difficult to meet the standards. In addition, heating boilers are generally built in or around cities, which is harmful to the health of citizens. The threat is greater, and now a large number of coal-fired hot water boilers are replaced by natural gas boilers to reduce environmental pollution caused by coal-fired heating. [0003] The traditional natural gas boiler adopts the countercurrent heat exchange between the return water of the primary pipe network and the flue gas, and the return water temperature o...

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Problems solved by technology

[0002] Coal-fired hot water boilers are usually used for heating in winter. However, due to the small steam capacity of coal-fired hot water boilers, the discharge of pollutants from boilers is difficult to meet the standards. In addition, heating boilers are generally built in or around cities, which is harmful to the health of citizens. The threat is greater, and now a large number of coal-fired hot water boilers are replaced by natural gas boilers to reduce environmental pollution caused by coal-fired heating

[0003] The traditional natural gas boiler adopts the countercurrent heat exchange between the return water of the primary pipe network and the flue gas, and the return water temperature of the primary pipe network is not lower than 70°C. The flue gas temperature is high, resulting in low thermal efficiency; in addition, after the combustion of natural gas, about 18% of the water vapor is discharged in the gaseous state in the flue gas. The latent heat of vaporization of water vapor is lost along with the flue gas, resulting in energy waste; in addition, when the natural gas hot water boiler is heated in winter, the boiler operates below the rated load for a long time, and the heating surface at the rear also has the problem of low-temperature corrosion

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