Multi-return-stroke gas-steam boiler

Abstract

The invention discloses a multi-return-stroke gas-steam boiler. The multi-return-stroke gas-steam boiler comprises a hearth. The front end of the hearth is connected with a burner. A steam outlet is formed in the top of the hearth. The upper portion of a backdraft chamber at the tail end of the hearth is communicated with a second-return-stroke smoke pipe. The other end of the second-return-stroke smoke pipe is communicated with a front smoke box. The front smoke box is communicated with a rear smoke box through a third-return-stroke smoke pipe. The front smoke box is divided into an upper front smoke box and a lower front smoke box. The third-return-stroke smoke pipe is communicated with the lower front smoke box. The rear smoke box and the upper front smoke box are communicated through a fourth-return-stroke smoke pipe. An annular air box is arranged on the periphery of the front smoke box and communicated with an inlet of the hearth through a hot air pipe. The steam outlet is communicated with the inlet of the hearth through a steam pipe. The fourth-return-stroke smoke pipe and the annular air box are additionally arranged, a proper amount of high-temperature steam is injected, so that burning in the hearth is improved, the maximal flame temperature is reduced, and therefore high-temperature oxynitride is reduced, the efficiency of the boiler is greatly improved, and meanwhile emission of harmful gas is reduced.

Description

technical field [0001] The invention relates to a gas-fired steam boiler, in particular to a gas-fired steam boiler which adopts four-pass structure, combustion pre-mixing technology and steam injection technology. Background technique [0002] With the implementation of coal-to-gas boilers, coal-fired steam boilers are about to be eliminated, and gas-fired steam boilers are becoming more and more widely used. Such as figure 2 As shown, the existing gas-fired steam boiler structure usually adopts a horizontal fast-installed internal combustion three-pass fire tube boiler, and generally uses a diffusion burner for combustion. Natural gas and air are not pre-mixed, but mixed by diffusion after spraying into the furnace. Burning while diffusing, the burning speed is slow and the flame is long, resulting in insufficient combustion. At the same time, the flue gas temperature in the furnace is too high, the concentration of nitrogen oxides is high, and the combustion efficiency o...

AI Technical Summary

Problems solved by technology

like figure 2 As shown, the existing gas-fired steam boiler structure usually adopts a horizontal fast-installed internal combustion three-pass fire tube boiler, and generally uses a diffusion burner for combustion. Natural gas and air are not pre-mixed, but mixed by diffusion after spraying into the furnace. Combustion while diffusing, the combustion speed is slow and the flame is long, resulting in insufficient combustion. At the same time, the flue gas temperature in the furnace is too high, the concentration of nitrogen oxides is high, and the gas combustion efficiency is low

The flame produced by the burner passes through the furnace, enters the combustion chamber, passes through the first return pass, the second return pass through the smoke pipe, and then is discharged into the atmosphere from the rear smoke chamber through the chimney. Due to the short flow of flue gas and the high temperature of the exhaust gas, it causes waste of energy

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