22 May 2002
According the combustion theory, fist law of thermodynamics and gas law, analyses are made on the dew-point temperature, saturated humidity and enthalpy of flue gas of combusted natural gas exhaust. The calculating equations for these parameters are derived and the corresponding calculating results are given in patterns of curves, which can be used as the base for actual engineering design. A new technical flow chart is put up what have a heat exchanger and three parallel heat pumps. Basing on it the actual COP of each heat pump can exceed 3. If the flue gas temperature is cooled down from 100?~200? to 40?~30?, the use of the sensible heat and latent heat of partial condensation of flue gas can be at a high level, and the thermal efficiency of natural gas can be raised 10%~20%.