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CO 2 emission estimation of cement production is an underlying tool to identify the CO 2 sources, to evaluate the reduction efforts and to set prospective reduction targets for the Chinese cement industry. However, lack of domestic data has limited the reliability and accuracy of CO 2 emission estimation for Chinese cement industry. To develop an accurate and comprehensive CO 2 emission factor for Chinese cement industry, this study established a factory-level database of 197 cement production lines from 21 provinces covering various capacity scales. On the basis of this database, process, fuel, electricity and synthesized emission factor were computed. Furthermore, bootstrap simulation and Monte Carlo simulation were applied to evaluate the uncertainty of these factors. After corrections for cement kiln dust (CKD), incomplete decomposition, organic carbon and inorganic carbon, the medians of process, fuel and direct emission factors are 525, 369, and 919 kg CO 2 /t clinker, respectively. Electricity emission factor is 74.9 kg CO 2 /t clinker. The final synthesized emission factor for cement product is 761 kg CO 2 /t cement with uncertainties of [−34.8%, +31.69%]. In this study, two revised calculation methods for the process emission factor are applied. Two calculation methods for the fuel emission factor are adopted as well. These practices seek to improve the reliability and accuracy of cement CO 2 emission factor. The simulated results indicate that the revised output method produces more accurate estimation for the process emission factor than the revised input method and unrevised output method. For fuel emission factor, the CC (carbon content) method is more accurate than the NCV (net calorific value) method. Simulated results are also compared with other authoritative estimation to validate the reliability of the CO 2 emission factors calculated in the present study. [ABSTRACT FROM AUTHOR]

Abstract: Cement is a primary component of concrete and is consumed extensively for construction and transportation infrastructures worldwide. Cement is largely produced and consumed locally but has global impact in terms of both energy consumption and greenhouse gas emissions. China is both the largest producer of cement and the biggest emitter of CO2 emissions in the world. It has been widely recognized that uncertainties of China׳s CO2 emissions were poorly quantified and clear discrepancies can be identified among different sources. These discrepancies arise from many uncertainties, including system boundary and statistical standards, availability of production data (especially for the clinker and cement outputs), and emission factors. We argue that the emission factors (EFs, either default values or adjusted ones) are the most important here and highlight the importance of clearly defining the CO2 accounting and reporting boundaries for determining the emission factors. We therefore developed a factory-level measurement for different types of clinker and cement production, primarily using onsite surveys and sampling, with the objective of distinguishing process-, combustion- and electricity-related emission factors on a factory level. It is a bottom-up CO2 emission inventory for China using the uniform formula and calculators and the first time factory-level sampling method (BFSM) based on three tiers of production lines, provincial and national integrations. Our results indicate that China׳s carbon emissions from cement production might be overestimated in the previous estimates because they overlooked the technology transition from the wet process to the dry process, differences in lime content and clinker-to-cement ratios, raw materials and fuels substitutions, and usages of blend additives. [Copyright &y& Elsevier]