抄録
Nowadays, reduction of CO_2 emissions is one of the most important problem in Japanese industry with respect to global warming. The improvement of boiler efficiency is the most effective for reduction of CO_2 emissions in industry boiler field compared with other CO_2 reduction technologies. The heat loss by flue gas is the major part in the total heat loss of the boiler. The natural gas has increased to be used for small boilers recently. It is easy to recover waste heat from flue gas of boiler. It contains about 15 vol. % of H_2O gas in flue gas of natural gas-fired boiler. So, we can get substantial improvement in boiler efficiency by recovering not only the sensible heat, but also the latent heat from the flue gas.
