Comparative analysis of carbon emission monitoring methods for gas-fired units based on HJ 75-2017 and accounting guidelines
Accurate carbon emissions data of gas units is one of the guarantees to ensure carbon trading.Many gas units recently installed online gas chromatography devices,so that the carbon emission is able to be real-time monitored from fuel part.For units that are not equipped with flue gas CO2 monitoring system or have no enough equipment space,conversion with flue gas O2 concentration is one of the feasible paths to monitor carbon emission from flue gas part.But whether direct measurement or conversion monitoring methods,there is still a lack of sufficient research on the deviation of continuous monitoring data from the fuel part and flue gas part.Therefore,for the gas units without capability to directly monitor flue gas CO2 in the short term,this study takes the historical data of an F-class gas-steam combined cycle unit for the simulation,and conducts continuous simulation monitoring and analysis based on the conversion with flue gas O2 concentration and online gas chromatography.It is found that there is no stable sorting rule of the monthly data and the relative deviation between different calculation methods.All the relative deviation of annual data is less than 5%.The correlation between δRD,R,fluegas-flue-h and the O2 concentration of CEMS is the highest.The deviation of carbon emission amount in the unit is mainly in the stable combustion section with a load ratio of more than 55%.In accordance with current standards or specifications,the O2 concentration of CEMS and the wet flue gas flow rate at the chimney outlet is most likely to cause the deviation of carbon emission amount from the fuel part and flue gas part.Under the existing technical specifications,the carbon emission from fuel part and flue gas part can be monitored in real time,which can be used for analysis on trend,but only the uncertainty of result from fuel part is below 5%.For gas units,the carbon emission monitored at fuel part is more appropriate,and the method monitoring the flue gas part may be more suitable for coal-fired units.
gas-fired unitscarbon emissionsfuel sourceflue gas sourcesimulation
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