Two-stage combustion of plain and N doped oil

Abstract

Number 2 fuel oil and Number 2 oil doped with pyridine were burned in a well insulated two-stage combustion apparatus to investigate NO emissions reduction using rich-lean combustion in nearly adiabatic combustion systems. The NO emissions were measured for a baseline condition without secondary air addition and these data were compared to the NO emissions from two-stage combustion with two secondary air flowrates. For plain fuel, many of the NO emissions trends followed thermal arguments; however, a second chemical NO formation mechanism was important for first stage equivalence ratios greater than about 1.3. Burned gas composition measurements at the exit of the first stage showed that HCN and NH 3 were formed in the rich No. 2 oil-air flames and the subsequent oxidation of these species in the lean second stage contributed significantly to the two-stage NO emissions. When N doped No. 2 oil was burned, the above phenomena limited the minimum yield of NO from the fuel N to about. 20.