Air Pollutants And Carbon Emission Inventory And Emission Reduction Potential Of Cement Industry In China

Cement industry is a resource-intensive and energy-consuming industry,which is also one of the main sources of air pollution emission.China is the world’s largest producer and consumer of cement.With the tightening of emission standards of air pollutants in cement industry in recent years,the emission level of air pollution in cement industry has changed significantly.In order to analyze the pollution characteristics and emission status of Chinese cement industry,this study adopts the"bottom-up"emission inventory compilation method based on the activity level of production line in the pollution discharge permit data and the emission factor data in the related technical guidelines.A 2020 emission inventory of major air pollutants(primary PM_2.5,SO₂,NO_x)and carbon dioxide（CO₂）in China’s cement industry has been established.Based on macroeconomic statistics,this paper predicts China’s cement output in 2021-2035 by using Long Short-Term Memory（LSTM）model,and combined with relevant pollution and carbon reduction technologies and policies in the cement industry.By setting different control scenarios,the paper forecasted and analyzed the path of pollution control and carbon reduction in China’s cement industry.The main results are as follows:（1）Based on the collection and collating of pollutant discharge permits data,statistical almanac and relevant technical guidelines,this paper established the activity level and emission factor database of China’s cement industry,adopted the"bottom-up"emission inventory compilation method,and constructed the emission inventory of major atmospheric pollutants(primary PM_2.5,SO₂,NO_x)and CO₂in China’s cement industry.In 2020,the emission of PM_2.5,SO₂,NO_xand CO₂in China’s cement industry were 142,251,709 and 1.35×10⁶Gg,respectively.（2）Based on the growth rate of fixed asset investment,urbanization rate of registered population and population data,the cement output in 2021-2035 is predicted by different methods.Through comparative analysis,the prediction results of LSTM model are selected.Based on geographical division,regional economic development and the scale of cement industry in each province,the spatial distribution of cement output in China was divided into four regions.The variation of cement output in different regions was predicted according to the urbanization rate and GDP growth rate,and the baseline emission scenario of China’s cement industry in2021-2035 was established.The results show that the emission of PM_2.5,SO₂,NO_xand CO₂in the baseline scenario of cement industry in 2025 are 145,255,710 and1.37×10⁶Gg,respectively.The PM_2.5,SO₂,NO_xand CO₂emissions under the baseline scenario for the cement industry in 2030 are 141,249,680 and 1.33×10⁶Gg,respectively,and 136,238,621 and 1.28×10⁶Gg in 2035,respectively.（3）In order to evaluate the impact of fuel substitution,clinker substitution and end-of-pipe control measures on air pollutants and greenhouse gas emissions,four scenarios were constructed,including baseline scenario,clinker substitution scenario,fuel and clinker substitution scenario and end-of-pipe control scenario.The results show that under the fuel and clinker substitution scenario,the emission reduction of SO₂is the best,with an average emission reduction of 11.4%.In the end-of-pipe control scenario,the reduction of NO_xis the largest,with an average reduction of26.1%.Under the clinker substitution scenario,PM_2.5and CO₂had the best emission reduction effect,with an average emission reduction of 4.23%and 4.88%respectively.In general,the emission reduction potential of PM_2.5and SO₂end-of-pipe control technologies will gradually be exhausted in the future,while low-carbon technologies have greater emission reduction potential in the medium and long-term emission reduction path.At the same time,the current cement industry NO_xemission standards still have certain emission reduction potential.For CO₂emissions,in addition to improved energy efficiency measures,increasing the level of clinker substitution also has great potential to reduce emissions.It is suggested that the next step is to combine research on more localized low-carbon technologies and dynamically evaluate information on industrial development and technological changes to build an emission control scenario that is more conducive to the synergy of pollution and carbon reduction.