Optimization On Natural Gas Boiler Exhausted Gas Waste Heat Recovery System

The natural gas boiler instead of the coal boiler is one of the main measures to improve the atmospheric environment quality in Beijing. The heat loss accounts for approximately 10% of the low grade caloric value of natural gas for the conventional natural gas-fired boilers without heat recovery. Therefore,one of the key technologies for saving energy of heating system is something called the waste heat recovery. This paper has studied the exhausted gas waste heat recovery system based on a new spray type heat exchanger and absorption heat pump to improve the energy efficiency for the natural gas boiler.This paper firstly established mathematical model of the natural gas boiler exhausted gas waste heat recovery system.Secondly, a simulate procedure was programmed.Thirdly, the mathematical model of gas boiler flue gas waste heat recovery system is verified according to experimental engineering test data. A practical case was used to calculate using the impeccable calculating program and analyze the influences of heating heat load, the temperature of back water of heating network and the climatic conditions. Multiple economic indicators was also used to analyze its economical efficiency.The studied results show that the price of natural gas and the meteorological condition could largely affect the optimization on configuration and thermodynamic parameters of the waste heat recovery system.The higher of the natural gas price, the bigger of the best configuration capacity of gas boiler flue gas waste heat recovery unit.Similarly, The economical efficiency will continue increasing along with it.For the same price of natural gas,the natural gas boiler flue gas waste heat recovery unit has the best configuration capacity.But it is not obvious for the influence of economy by changing the temperature of heating network.The critical prices of natural gas are different under different climate conditions and parameters of heating.The technology of waste heat recovery from gas boiler exhausted gas could save the consumption of natural gas about 10% on the premise of meeting the heating demand.The technology could also decrease the emission of polluting gases like CO2, nitrogen oxides and so on.The spray type configuration of a heat recovery absorption heat pump integrated with a natural gas boiler has a huge potential for the northern heating area because of the better economic efficiency and environmental benefits.