天然气热利用率及影响因素

Analyses on Thermal Efficiency of Using Natural Gas and Impact Factors

用热力学理论和燃烧理论建立了天然气排烟温度与热利用率的计算模型，计算得出了天然气热利用率与排烟温度的关系曲线，可供实际工程参考．对影响天然气热利用率的因素（排烟温度、过剩空气系数和烟气冷凝温度）的主要影响因素（燃烧空气含湿量）进行了定量分析，提出了提高天然气热利用率的措施，可使天然气的热利用效率提高10％～20％．

According to the combustion theory, the first law of thermodynamics and the gas law, a calculation model is established. It calculates the relation ship between thermal efficiency of natural gas and flue gas temperature which is shown as curves. Analyses are made on the impact factors such as the dew-point temperature, saturated humidity, and enthalpy of flue, gas of combusted natural gas. The technical means is put forward for increasing thermal efficiency. For the high temperature flue gas, the waste heat boiler or air preheater can be used; for the low temperature flue gas, combustion-supporting air can be preheated or humidified, and then the heat pump is used for waste heat recovery from flue gas of natural gas. It can reach the aim of the stair-step usage of the combusted natural gas. The use of the sensible heat and latent heat of partial condensation of flue gas is more efficient, and the thermal efficiency of natural gas can be raised by 10%-20%.