Improving Furnace and Boiler Cost-Effectiveness and CO2 Emission by Adjusting Excess Air

摘要

Reducing the input excess air or airflow rate to a furnace or boiler will result in decreasing transmission rate of the thermal flow from, the radiation zone to the convection heating surface zone in the furnace. Results of the plant-scale test presented in this article show that if the furnace is operated at 3.6 X 10~7 kcal/h of combustion capacity, decreasing the residual O2 concentration in the furnace flue gas from 4% to 2.5% will save 9.3 x 10~3 m~3 of natural gas consumption, and 2.1 X 10~4 tons of CO2 emission annually. For the boiler tested in the study, 1.8 X 10~5 m~3 of natural gas consumption and 3.9 X 10~5 tons of CO2 emission will be reduced annually if it is operated with 90 ton/h steam yield. Hence, controlling the input excess air (or oxygen) as an important operating alternative to enhance thermal efficiency, and alleviate environmental impact of a heater furnace and boiler has been confirmed in this research.