Fuel-NO_x emissions reduction during the combustion of LCV gas in an air staged Winnox-TUD combustor

摘要

NO_x emissions from fuel-bound nitrogen (FBN) form one of the biggest challenges related to the combustion of biomass derived low calorific value (LCV) gas. To decrease the conversion of FBN to NO, one can intervene at different locations of the system: Upstream of the combustor using for example wet scrubbing techniques, downstream of the combustor using selective catalytic reduction (SCR), or selective non catalytic reduction (SNCR), or within the combustion system itself by optimizing the combustion process and the design parameters. In this research work, the third approach was adopted, where a new combustor called "Winnox-TUD" was developed and tested. Winnox-TUD is an air staged combustor. Ammonia was injected in the LCV gas to simulate the FBN. In this paper the effect of stoichiometry in the first stage in addition to the effect of methane and ammonia concentrations on the conversion rate of FBN to NO are presented. Results are presented for both LCV gas containing and not containing natural gas in order to define the effect of methane. A minimum in the conversion rate of ammonia to NO was found at an air number in the primary stage (A) between 0.7 and 0.8.