Experimental investigation of high-impulse oxygen lancing to achieve ultra-low nitrogen oxide formation in air- and oxy-fuel co-combustion

• High-impulse oxy-fuel hydrogen and natural gas combustion • Two burner-setup to recreate industrial conditions in air- and oxy-fuel co-combustion • Investigations include oxygen enrichments up to 60%, hydrogen enrichments up to 85% • NO X emission reduction up to 72% compared to state-of-the-art air-fuel combustion Via the replacement of individual burners in industrial furnaces with hydrogen ready oxy-fuel burners, energy consumption and CO 2 emissions can be significantly reduced at low investment costs. A main issue that often arises by air- and oxy-fuel co-combustion, especially for hydrogen combustion, is an increase in thermal NO X . A prototype oxy-fuel burner designed for industrial application in such a co-combustion environment is experimentally investigated. The investigated burner uses a novel concept with choked flow oxygen lancing, resulting in an underexpanded jet. Therefore, two burners with a combined power input of up to 635 kW are installed onto a test furnace equipped with several measurement instruments. The results from air-fuel combustion are used as a baseline to compare the effects of standard oxy-fuel co-combustion with high impulse oxy-fuel co-combustion in terms of NO X formation. Additionally, the results include temperature profiles and heat flux profiles for staged and non-staged cases for global hydrogen enrichments up to 85% and global oxygen enrichments up to 60%. Results showed significant reduction in NO x formation by high impulse oxygen lancing. Compared to the air-fuel combustion case a reduction of up to 72 % was achieved. Furthermore, the choked flow lancing did not show negative consequences in terms of operational safety, flame stability and temperature or heat flux distribution.