It contains large amounts of hydrogen fuel, burning a large amount of water vapor. Each 1NM3 natural gas combustion produces steam 1.55KG, with considerable latent heat of vaporization of about 3700KJ, accounting for about 10% of the calorific value of natural gas. At higher exhaust gas temperature, water vapor from condensing heat release, it is wasted with the flue gas emissions heat. Meanwhile, the high temperature flue gas also took away a lot of sensible heat loss together to form a larger exhaust. Flue gas condensing heat recovery unit, the use of low-temperature water or air cooling the flue gas, flue gas temperature is reduced to achieve close to the heat exchanger surface area, the flue gas condensation of water vapor, while achieving significant smoke and heat release latent heat of condensation of water vapor release, and the water or air heat exchanger inside is heated to achieve heat recovery, improve boiler thermal efficiency. Boiler thermal efficiency: 1NM3 natural gas combustion flue gas production theory about 10.3 NM3 (about 12.5KG). In excess air factor of 1.3, for example, produce smoke 14 NM3 (about 16.6KG). Take flue gas temperature down to 200 ℃ 70 ℃, release physical sensible about 1600KJ, water vapor condensation rate Take 50% release latent heat of vaporization of about 1850 KJ, total heat release 3450 KJ, about 10 percent of natural gas calorific value. If we take 80% of the flue gas into the heat recovery, thermal efficiency can be improved more than 8 percent, natural gas fuel savings of nearly 10%. Traditional boiler, the exhaust gas temperature is generally 160 ~ 250 ℃, the water vapor in the flue gas is still in the superheated state, it is impossible to condense into liquid water and the release of latent heat of vaporization. As we all know, the boiler thermal efficiency is low calorific value fuel calculated, is not considered a high calorific value fuel heat loss in the heat of vaporization. So the traditional boiler thermal efficiency is usually only 87% to 91%. The condensing heat recovery boiler, which the exhaust gas temperature is reduced to 50 ~ 70 ℃, full recovery of the latent heat in flue gas sensible heat and water vapor. Gas-fired condensing boiler flue gas heat recovery steam volume component is generally 15% to 19%, oil-fired boiler flue gas water vapor content of 10% to 12%, much higher than the flue gases of coal-fired boilers 6% of the water vapor content. Currently boiler thermal efficiency are low calorific value calculation, although nominally high thermal efficiency, but because of high natural gas, low calorific value difference of about 10%, the actual energy efficiency to be increased. To take full advantage of energy, reduce exhaust gas temperature, flue gas recovered physical energy, when the heat exchanger wall temperature is below the dew point of the flue gas temperature, flue gas water vapor is condensed, releasing latent heat, 10% of high-low the difference between the amount of heat can be used effectively. If the boiler flue gas temperature dropped to a low enough level, then the smoke was superheated water vapor will condense and release latent heat of vaporization. Condensing heat recovery device is through the condensing flue gas water vapor, so that one of the latent heat of vaporization is utilized, thereby improving thermal efficiency, even the thermal efficiency of a gas-calorific-based calculation may reach or exceed 100% of such waste heat recovery It is called condensing heat recovery device. ▲ heating surface made of alloy structure, effectively prevent condensate corrosion ▲ design according to the actual situation of the user each boiler. Small smoke resistance, light weight device.