Renewable natural gas (RNG), produced from biogas upgrading, is an important alternative to fossil fuels. Unfortunately, RNG contains several trace contaminants, one being NH 3 , of particular concern for RNG produced from farming operations. The presence of NH 3 in RNG, particularly if it is injected into the natural gas (NG) pipeline network, could have serious consequences, ranging from damage to the NG infrastructure, to corrosion of the end-user equipment, and increased pollutant formation during combustion. This paper is part of a broader investigation studying all such impacts, the focus here being pollutant emissions. Two common end-user equipment were tested: An internal combustion engine and a household water heater, both operating with NG injected with NH 3 with concentrations ranging from 0 to 500 ppmv. Emissions studied included unburned hydrocarbons (UHC), CO, and nitrogen oxides (NO x ), the latter being of key concern. The presence of NH 3 resulted in increased NO x emissions for both equipment. For the water heater, the relationship between the amount of NO x formed and the NH 3 concentration was quantitative: For every molecule of NH 3 fed to the water heater, one molecule of NO x was additionally produced. However, for the engine a lower quantity of NO x was formed, to that corresponding to complete conversion. The results with both devices are significant, indicating the need for thorough RNG purification prior to its injection into the NG network.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.