In the next stage, when the coverage of the national carbon market is expanded, the priority of industries to be included is: cement manufacturing, steel making, flat glass manufacturing, etc. The carbon emissions of China's cement account for 13.5% of the total emissions, about 1.2 billion tons. In the face of such huge emissions, how should the cement industry reduce carbon? What are the opportunities for cement enterprises and how to carry out carbon accounting and decarbonization to meet the carbon market? Technical path of energy conservation and carbon reduction in cement industry 1. Improve energy efficiency technology It aims to improve the performance and efficiency of existing cement industry equipment, reduce system energy consumption through technical optimization and local improvement, and achieve the purpose of carbon emission reduction. Cement enterprises can use it in combination according to the actual equipment and process conditions. 1) Integral lifting technology of refractory for cement kiln 2) Preheater separation efficiency improvement and resistance reduction optimization technology 3) Transformation of five-stage preheater to six-stage preheater with low energy consumption 4) Self-denitration and capacity expansion optimization technology of calciner 5) Cooling machine upgrading technology (the third generation is replaced by the fourth generation) 6) The cooler is replaced by the central roll breaking technology 7) Oxygen-enriched combustion technology 8) Optimization and transformation of kiln burner 9) Raw meal burnability and operation management improvement technology 10) External circulation technology of raw material for vertical roller mill 11) Roller press raw material final grinding technology 12) Cement grinding optimization and lifting technology 13) Steel slag/slag roller press final grinding technology 14) Steel slag vertical roller mill final grinding technology 15) Energy saving technology for fan efficiency improvement 16) Digital and intelligent technology
2. Alternative technologies of raw and fuel About 60% of CO2 emissions from cement industry come from carbonate decomposition, about 35% from fuel combustion, and about 5% from indirect emissions from power generation. Replacing fossil fuels with waste derived fuel (RDF), biomass fuel, plastics, rubber, leather, waste tires and other alternative fuels can reduce carbon emissions from fuel. On the other hand, replacing limestone with calcareous industrial solid waste can significantly reduce carbon emissions from carbonate decomposition. This technical direction aims to reduce the carbon emissions of the cement system from the perspective of technology through the use of different raw materials or fuels, starting from the substitution of raw materials and fuels. Cement enterprises need to choose to use it under the national incentive policies according to the environmental conditions and their own conditions. 1) Alternative fuel collaborative disposal technology 2) Alternative fuel pre-calcination equipment and technology 3) New energy alternative technology 4) Cement clinker production technology using carbide slag instead of limestone raw materials 5) Vertical grinding equipment technology of ultra-fine metallurgical slag 3. Low carbon cement technology The purpose of low-carbon cement is to reduce the carbonate used in the production of cement clinker, or reduce the amount of clinker. 1) High belite sulphoaluminate silicate (ferroaluminate silicate) cement technology 2) Low-heat Portland cement and medium-heat Portland cement and their preparation technology 3) Grading and separate cement grinding technology 4) Calcination of kaolin to produce low-carbon cement 5) Complete set of technology for production of sulfuric acid and cement from industrial by-product gypsum 4. Carbon capture and storage technology The carbon capture and storage technology directly captures and purifies the carbon dioxide generated in the cement production process, and is used in other industrial fields or food processing, chemical utilization or direct storage, which directly reduces the carbon dioxide emissions of cement enterprises. 1) All-oxygen combustion coupled low energy carbon capture technology 2) Carbon dioxide capture technology for cement kiln flue gas 5. Prospect of carbon emission reduction technology for cement enterprises in the future 1) New circulating suspension calcination technology for cement clinker. The new circulating suspension calcination technology changes the stacking state in the rotary kiln into fluidization, so the gas-solid two phases in the system are fully contacted, and the heat exchange efficiency is improved. Compared with the existing new dry-process cement clinker calcination process of the same scale, the heat consumption is reduced by more than 10%, and the power consumption is reduced by more than 5%. 2) Research on calcination of cement with clean electric energy. Driven by national policies, the country will gradually move towards controlling the consumption of high-carbon energy in the future, replacing high-carbon power with low-carbon power, and promoting non-fossil energy. In this case, the cement industry may develop towards the electrification of green power. If it is considered that the future cement production lines will all use green electricity with clean electricity to realize the electric calcination of cement in the cement plant, it can play a significant role in reducing emissions. 3) Green ecological smart mine. The technical approaches adopted by the green ecological smart mine include: the ecological environment of the mining area is harmonious, and the greening coverage rate and ecological restoration rate of the greening area of the mining area can reach 100%; Zero discharge of mine solid waste and 100% resource utilization rate; Intelligent mine production equipment and unmanned production site; Mine safety production and intelligent ore blending. Finally, the park type mining area with harmonious and friendly ecological environment will be built to improve the carbon sink capacity of the mining area ecosystem and realize "zero carbon" mining. 4) Improve the utilization efficiency of cement products. The improvement of utilization efficiency of cement products can effectively reduce the use of cement products. At present, cement consumption should be reduced as much as possible on the basis of ensuring concrete performance. The demand for cement can be reduced by improving the effective use rate of concrete in buildings and infrastructure, replacing cement with wood and other building materials in the construction field, recycling cement, recycling concrete and reusing after treatment, and developing and using new concrete products with low cement consumption. Therefore, relevant technical specifications, construction specifications and design specifications need to be further revised to improve the efficiency of cement products. In addition, in project management, it is also necessary to strengthen the control of cement utilization efficiency, promote the reduction of cement consumption through better and more detailed management, and give direct support to cement carbon neutralization. 5) Realize clinker substitution and adjust the raw material structure of cement products. Looking for some active materials to replace or reduce the use of clinker is also a way to save coal and reduce carbon. In the process of project construction, it is also an important way to use cement differently according to the needs of concrete performance. For example, masonry cement is widely used in non-load-bearing structures such as masonry and plastering. 6) Due to the limitation of carbon sequestration or carbon utilization technology, carbon capture technology can not directly and significantly reduce the carbon emission level at present, but because this technology can directly reduce the final CO 2 emission and achieve the maximum CO 2 emission reduction effect, it can be favored by more cement enterprises with the support of corresponding standards.
