Experimental research on performance response of domestic gas cookers to variable natural gas constituents

In China, the imported Liquefied Natural Gas (LNG) has been steadily increased in past years, with its constituents different from those of traditional pipeline natural gases (PNG) to various extents. In this paper several natural gases to be delivered to Guangdong provinces in China were selected as test gases to measure performance response of 17 sets of domestic gas cookers. Heat input rating, CO and NOx emission, and thermal efficiency was measured according to related national standards. American Gas Association indexes and Weaver indexes were used to predict combustion stability and emission under different gas constituents. Experiment results were compared with prediction to analyze the applicability of the two well-established indexes systems. It was concluded that Wobbe Index can predict heat input rating quite accurately, and CO and NOx emissions can be remained with reasonable limits for the changing constituents discussed. For combustion stability prediction, judgment criteria should be adjusted as follows: Weaver lifting index from JL ≥ 0.64 to JL ≥ 0.95, Weaver incomplete combustion index from JI ≤ 0.05 to JI ≤ 0.04, and AGA lifting index from IL ≤ 1.10 to IL ≤ 1.05.