The condensing boiler use the high-efficiency flue gas condensation waste heat recovery device to absorb the residual heat in the exhaust of the boiler tail and the latent heat released by the condensation of water vapor to achieve the purpose of improving the thermal efficiency of the boiler.
The amount of latent heat of water vapor in the condensing boiler that can be recovered from the flue gas is related to the type of fuel used in the boiler and the outlet temperature of the boiler. When the ordinary boiler without the condensing recovery device burns natural gas, if the thermal efficiency of the boiler is 90%, after the condensing waste heat recovery device is used, the exhaust gas temperature is lowered to 30℃ to 50 ℃, and the thermal efficiency is increased to about 107%. In the case of constant fuel consumption, the lower the return water of the heating system, the more heat is recovered by the condensing waste heat recovery device, and the thermal efficiency of the boiler is higher.
Condensing boilers mainly include integrated condensing boilers and separate condensing boilers. The integral type of condensing boiler is characterized in that the condensation of water vapor in the flue gas is realized inside the boiler, and there are mainly two types of heat exchangers and inverted burners. The condensing boiler of the two-stage heat exchanger is divided into a radiant heat exchanger and a convection condensing heat exchanger. The integral type condensing boiler has a large transformation to the boiler body, and the flue structure and resistance vary greatly, and it is necessary to increase the power of the large fan; The condensate is produced in the furnace and requires a corrosion resistant heat transfer surface; The performance of the burner is obviously different from that of the non-condensing boiler. Generally, the cost of the integrated condensing boiler is 1.6 to 2 times that of the conventional boiler.
At present, there are fewer bulk condensing boilers with larger capacity, usually with separate structure. The condensing part of the steam in the flue gas is realized outside the boiler, and the economizer device similar to the coal-fired boiler is called a flue gas condensing heat energy recovery device. If the exhaust temperature of the gas boiler is reduced to a sufficiently low level, the superheated water vapor in the flue gas will condense and release the latent heat of vaporization, this is called a condensing boiler. Condensing boilers are being vigorously promoted at home and abroad, so we should pay enough attention to the condensing boilers.