Integrated methods to improve efficiency of furnace burning recovered tail gas

摘要

Replacing nature gas (NG) by recovered hydrogen-rich tail gas to fuel a full-scale furnace has been proved to improve furnace efficiency and reduce NO_x formation. Adjusting residual O_2 concentration in flue gases, air preheat temperature and furnace damper angle will further improve the efficiency of the furnace burning the recovered hydrogen-rich tail gas. Prolonging the residence time of the hot gas flow increases the heat release time and reduces the time for the fuel to reach burning temperature so that the furnace efficiency can be improved. On-site test results using a full-scale furnace show that reducing the residual O_2 concentration in flue gases from 4.0 to 3.0 vol.% raises the furnace efficiency by 0.6%. Raising the pre-heated incoming air temperature from 200 ℃ to 240 ℃ and reducing furnace damper opening angle from 45° to 39° save 2.4 x 106 and 1.9 x 106 m~3 of natural gas, respectively. Integrating the adjustment of flue gas residual O_2 concentration, temperature of incoming air temperature, and furnace damper opening angle will assist industries in achieving higher overall furnace efficiency and reducing carbon dioxide emission.