A Experimental Study On The Influence Of Hydrogen Content In Natural Gas On Combustion Appliances

Natural gas mixed with hydrogen can accelerate combustion rate and reduce the pollutant emissions.At the same time,it may also have an adverse impact on existing applications.The research on the natural gas mixed with hydrogen is mainly focused on the internal combustion engine,and the research on the effect of hydrogen on the combustion appliances for heating is not deep enough.SNG is also an important new way to solve the contradiction between supply and demand of natural gas in China.However,less research concentrated on the combustion characteristics of SNG in the 12 T gas appliances was found.In this study,natural gas mixed with hydrogen was utilized to investigate the influence of hydrogen content in natural gas on the heat load,pollutants emissions,and flame stability of combustion appliances.Meanwhile,according to the characteristic of SNG containing a small amount of hydrogen,natural gas mixed with a small amount of hydrogen was used to substitute SNG in the experiment.The applicability of interchangeability methods to SNG and the combustion stability of SNG in the 12 T gas appliances were studied by theoretical calculation and experimental analysis.Base on theoretical calculations,The influence of changes in hydrogen contents on the parameters of the mixed gas was analyzed by comparing the high heat value,the Wobbe index,and the combustion potential of the mixed gas.Meanwhile,the hydrogen volume fraction was obtained when the characteristic index of the mixed gas exceeds the range of 12 T natural gas.The argon burning potential and the AGA index method of the gas interchangeability methods are selected to determine the interchangeability of the mixed gas contained different hydrogen contents and the selected reference gas.At the same time,the mixing ratio of hydrogen was obtained when the mixed gas exceeds the limit of stability index.It is found that the head load of the gas appliances decreases with the increase of the hydrogen contents of the mixed gas.When mixed with no more than 5% hydrogen,the deviation between the designed heat load and the measured heat load is less than 10%,which meets the requirements of the standard.In the pollutants emission test,the carbon monoxide emission value decreases with the increase of the hydrogen content,and the NOx emission value of the most gas appliances change slightly and no obviously fluctuation.in case of Natural gas mixed with a small amount of hydrogen,there is no stability problem in the combustion of gas appliances.The stability test results are basically the same at 100% and 50% load ratio.The limit hydrogen ratio in the theoretical calculation results is close to the experimental results.At the same time,it is proved that a small amount of hydrogen in SNG does not cause stability problems to 12 T gas appliances.The gas interchangeability methods is also applicable to SNG.