Calculate the waste heat quantity and recovery rate of the liquid and gas fuel's low grade fuel

In China's energy structure, the consumption of various liquid and gas fuels grows rapidly. After these fuels are combusted, the discharged flue's temperature is generally about 160~180°C. There is a lot of low-temperature waste heat in the flue. This part of energy can be used as secondary energy, though which energy's grade is low. Lots of H elements are in the Liquid and gas fuel, and the vapor is the flue's main ingredients. In this paper, the waste heat quantity and recovery rate of 0# light diesel oil and natural gas's flue are calculated, which temperature is from 180°C to 25°C, at the condition of 1 atm. In the 0# light diesel's flue, the proportion of residual heat of the vapor is about 55.08%. And in the natural gas's flue, which proportion is about 79.41%. Moreover, the vapor's latent heat is about 3/4. So for the low temperature flue's heat recovery, recovering the latent heat of vapor is of great significance.