Modeling the dynamic mechanism between cement CO2 emissions and clinker quality to realize low-carbon cement

• We establish a synthetic CO2 emission accounting framework to develop low-carbon cement clinker product.
• This framework can model the relationship between cement clinker CO2 emission factors (fuel and process) and clinker quality control indicators.
• An optimization proportion model is embedded into the framework to accommodate different raw materials.
• Controlled decrease of clinker quality can reduce CO2 emission of clinker manufacturing.

To devise low-carbon cement clinker product, in-depth knowledge about the variation mechanism of cement clinker CO2 emissions is the prerequisite. The determinants of cement clinker CO2 emissions in Chinese cement industry have been inquired by several researches recently. However, the impacts and abatement effect of clinker quality on cement clinker CO2 emissions have not been identified yet. In technological sense, there lacks an integrated quantitative model that can elucidate the dynamic mechanism between cement clinker CO2 emissions and clinker quality. To fill this gap, this paper devises a CO2 emission accounting framework integrated with optimization model to explore the dynamic mechanism between cement clinker CO2 emissions and clinker quality. Based on survey data of 2 typical cement clinker production lines in China, the accounting framework is validated with measured data. Through numerical simulation within this framework, a set of sensitivity analysis is conducted. The results indicate that if the target KH (lime saturation ratio) of both production lines climb from −5% to +5%, the process CO2 emission factor will give rise to an increase of about 16.4 and 14.8 kg CO2/t clinker, respectively. With the same variation, the fuel CO2 emission factors of two production lines will gain 17.2 and 13.7 kg CO2/t clinker, respectively. Obviously, controlled decrease of clinker quality can reduce CO2 emission of clinker manufacturing. The results of sensitivity analysis are robust and highlight the remarkable role of clinker quality in both process and fuel emissions. Besides, the integrated framework can provide in-depth investigation into the dynamic mechanism between CO2 emissions and the other determinants. Using this framework, cement plants or industry can develop optimal clinker quality standards on a quantitative basis to achieve low-carbon clinker.

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