Waste heat recovery for condensing type anti-corrosive gas/oil-fired boiler

Abstract

The invention discloses a waste heat recovery for condensing type anti-corrosive gas/oil-fired boiler, which can effectively recover the physical heat of boiler flue; not only lots of sensible heat is recovered, but also the latent heat of vaporization discharged by condensation of water vapor. The structure is as follows: a common heat tube heat exchanger body and a solution spraying device are included. The heat tube heat exchanger body is used for transferring the heat from the flue side to the other side by the shock transmission of the heat tube, so as to heat the air or water; the solution sprayed by the sprayer is uniformly distributed in the heat exchange tube on the flue side and on the inner wall of the heat exchanger, so as to remove the corrosion from the weakly acidic solution formed by condensation of water vapor in the flue of the boiler.

Description

technical field [0001] The invention relates to a waste heat recovery system, in particular to a waste heat recovery system capable of recovering sensible heat and latent heat of steam gasification of gas / oil-fired boiler flue gas and preventing the heat exchanger body from being corroded by weakly acidic gas. Background technique [0002] Natural gas or fuel oil contains a considerable amount of hydrogen, and the amount of water vapor produced by combustion is large. Among them, the water vapor volume composition in the flue gas of gas-fired boilers is generally 15%-19%, and the water vapor volume composition in the flue gas produced by oil-fired boilers 10%-12%. The exhaust gas temperature of gas boilers is generally 120-250°C, and 7%-15% of the sensible heat and 11% of the latent heat in the flue gas are directly discharged into the atmosphere without being utilized, which not only causes a lot of energy waste but also exacerbates the thermal pollution of the environment...

AI Technical Summary

Problems solved by technology

The exhaust gas temperature of gas boilers is generally 120-250°C, and 7%-15% of the sensible heat and 11% of the latent heat in the flue gas are directly discharged into the atmosphere without being utilized, which not only causes a lot of energy waste but also exacerbates the thermal pollution of the environment

In order to make full use of energy and recover the physical heat energy of the flue gas, the waste heat recovery of the flue gas is often carried out by reducing the exhaust gas temperature, and when the wall temperature of the heat exchanger is lower than the dew point temperature of the flue gas, the water vapor in the flue gas It will be condensed, and this process can recover a large amount of latent heat of water vapor. At the same time, the acid gas contained in the flue gas forms a weak acid solution, which is easy to cause acid corrosion on the wall of the heat exchanger. Therefore, in order to prevent the corrosion of the heat exchanger, the boiler smoke Gas waste heat is generally discharged to the atmosphere above the dew point temperature, that is, only a part of the sensible heat is recovered, and the latent heat is basically not effectively recovered. This is the root cause of the low recovery rate of gas / oil-fired boiler flue gas waste heat

Some Chinese patent application documents (such as 200420049576, 200910048782, 200910238452, 2009102617842, 201010225079X) mentioned the recovery of boiler flue gas latent heat, but did not consider the corrosion of weakly acidic condensed water on the heat exchanger body, which will seriously affect the heat exchanger service life, the overall economic benefit is not obvious

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