Experimental Study of Fuel Lean Reburning for NOx Reduction in Oxygen Enhanced Combustion

This experimental study is focused on a fuel-lean reburn system to control NOx emission from combustion process. In the conventional reburning process, 20 similar to 25% reburn fuel of total heat input is used. As a consequence, about 45% NOx emission reduction is achieved. And it requires additional burnout air to restrict CO emission level in acceptable limit. However, in the fuel-lean reburn system, by contrast, the amount of injected reburn fuel into the reburning zone is low enough to maintain overall fuel-lean condition in the furnace, so that no additional burnout air system is required, and CO emission can be maintained at almost zero level. 15kW lab scale combustor is used to examine the formation characteristics of NOx with various oxygen enhanced combustion conditions. LPG (Liquefied Petroleum Gas) was used as main fuel and reburn fuel. Finally, the current fuel-lean reburn system, even with only an amount of reburn fuel of 13% of total heat input, was observed to achieve a maximum of 48% in NOX reduction.