Consistent Emission Correction Factors Applicable to Novel Energy Carriers and Conversion Concepts

Abstract

Volume correction factors have been an important aspect when reporting pollutant emissions from gaseous combustion for many years. Their application has become standard procedure in such a way that their applicability is seldom questioned. However, their emergence dates back to a time when power generation primarily relied on conventional fuels such as coal and gas. The advent of alternative fuels and new combustion concepts reveals the classical correction formula prescribed by current regulations to produce results that can be misleading when comparing different mixtures with regard to their emission behavior. For this reason, this work derives a more generalized correction formula that is applicable to arbitrary fuel-oxidizer combinations and is based on the same principles as conventional volume correction. The impact of the choice of correction formula is then illustrated by comparing results for various fuels for a simple equilibrium calculation as well as experimental data from a premixed swirl combustor and a pulse detonation combustor. The results show that the derived correction terms allow for an unbiased comparison of emission behavior in a similar manner as alternative fuel mass based metrics such as emission index, as long as the amount of intermediate reactants and radicals within the exhaust gas remains comparably low. It is suggested that future emission regulations should incorporate the issues discussed in this work to ensure unbiased comparison of emission values across a wide range of combustion applications.