Calculating of CO2 emission factors for Chinese cement production based on inorganic carbon and organic carbon

Abstract

Cement industry is one of the largest anthropogenic carbon dioxide (CO2) emitters in the world, and its emission accounts for 5–7% of the total anthropogenic CO2 emission. As the biggest cement producer, China has attracted worldwide attention in mitigating cement CO2 emission. Many studies did not reflect China's actual emission due to not fully knowing the de-facto cement production in China. The carbon emission factors (EFs) are important parameters to calculate CO2 emission. There are uncertainties in determining Chinese carbon emission factors on cement production. This study analyzed the composition of samples from cement production lines in China and used the raw material carbonate method (RMCM) to calculate process-related EFs of new suspension pre-heater and pre-calciner (NSP) kilns, and it shows that RMCM is more accurate and simpler than other methods. This research also indicates that process-related EF is more accurate when calculation is based on the carbonate (inorganic carbon, IC) decomposition ratio, and the combustion-related EF is more proper when multiplying the total organic carbon (TOC) by the organic carbon combustion ratio, because the majority of the clinkers always contain small amounts of the carbonate that are not fully decomposed and small amounts of fossil fuels (FFs) that are not completely combusted.