Device and method for recycling smoke condensate heat energy of gas boiler in heat pumping mode

Abstract

The invention relates to a device and a method for recycling smoke condensate heat energy of a gas boiler in a heat pumping mode. The device and method for recycling the smoke condensate heat energy of the gas boiler with high heat energy recycling rate do not exist at present. The device provided by the invention comprises a high-efficient condensate heat exchanger, a primary circulating water heat exchanger outlet pipe, a smoke inlet pipe and a smoke outlet pipe, and is characterized by further comprising a heat pump unit, a primary circulating water heat pump inlet pipe, a primary circulating water heat pump outlet pipe, a primary circulating water pump, a domestic hot water taking pipe, a primary circulating water replenishing pipe, a secondary circulating water pump, a secondary circulating water heat pump inlet pipe and a secondary circulating water heat pump outlet pipe, wherein one end of the primary circulating water heat pump outlet pipe and one end of the primary circulating water replenishing pipe are both connected with the other end of a primary circulating water heat exchanger inlet pipe; the secondary circulating water pump is mounted on the secondary circulating water heat pump inlet pipe; a secondary circulating water heat pump outlet temperature gauge is mounted on the secondary circulating water heat pump outlet pipe. The device provided by the invention is high in heat energy recycling rate.

Description

technical field [0001] The invention relates to a device and a method for recovering the condensation heat energy of gas-fired boiler flue gas, in particular to a device and method for recovering the condensation heat energy of gas-fired boiler flue gas in a heat pump mode. Background technique [0002] The exhaust gas of gas-fired boilers is generally above 150°C, and the flue gas contains water vapor with a volume fraction of 15%-20%. This part of the water vapor is in a superheated state, and its latent heat of vaporization cannot be utilized. When the flue gas is discharged, it causes a huge loss of heat. At present, gas-fired boilers are gradually replacing coal-fired boilers. Gas-fired boilers have been widely used in urban life and production heating, and the condensation recovery devices of gas-fired boilers have begun to be used. [0003] At present, gas-fired boiler condensation recovery mainly uses a single flue gas-water heat exchanger to lower the temperature o...

AI Technical Summary

Problems solved by technology

[0004] (1) The temperature of hot water is too low, it can only be used for domestic hot water or heating boiler feed water, etc.

[0005] (2) The flue gas temperature cannot be lowered low enough

The water heated by the flue gas is mainly domestic hot water or boiler feed water. The feed water of the steam boiler is small, and the return water temperature of the hot water boiler is high, which cannot reduce the temperature of the flue gas to a low enough level. The domestic hot water requires an outlet temperature of 40-60 °C, the exhaust gas temperature is mostly above 60 °C, the condensation ratio of water vapor in the flue gas is not high, and the heat energy recovery rate is low

[0006] (3) The solution sprayed by the nozzle in the condensing heat exchanger is in direct contact with the flue gas for heat exchange, and part of the heat in the flue gas is discharged with the solution, which reduces the heat recovery efficiency

[0007] There are also other ways to recover gas-fired boiler flue gas condensation heat energy. For example, in the Chinese patent with the publication date of August 29, 2012 and the publication number CN102650431A, a method for cascaded recovery and utilization of gas-fired waste heat is disclosed. The gas waste heat cascade recovery and utilization method uses the series connection of two different heat transfer methods: air-water indirect heat exchange and air-water direct heat exchange. Two consecutive upgrades, the temperature rises to 60-100°C, and it is used as steam boiler replenishment water, waste heat boiler replenishment water, other process water or domestic hot water. This system needs to consume high-grade electric energy and has a single function

[0008] To sum up, there is no one with a high heat recovery rate. The water temperature of the primary circulation water is 15-30°C, which can fully cool the flue gas, reduce the flue gas to below the dew point, and fully recover the sensible heat and water of the flue gas. Apparatus and method for recovering gas-fired boiler flue gas condensation heat energy of latent heat of vaporization of steam

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