cement grinding accounts for about 60% -70% of the comprehensive power consumption of cement. Therefore, the energy saving and consumption reduction of grinding system has become the top priority for cement enterprises to reduce costs and increase efficiency.
On September 12, the "2023 Cement'Double Carbon 'Conference and the 10th China Cement Energy Conservation and Environmental Protection Technology Exchange Conference" sponsored by China Cement Network was held in Zhengzhou, Henan Province. Wu Yaoyao, a professor-level senior engineer of Sinoma International Engineering Co., Ltd. (Nanjing), gave a brilliant speech on the theme of "Energy Saving and Consumption Reduction of Cement Grinding System & Green and Low Carbon".
In recent years, the technology of China's cement industry has been progressing. In fact, the most complex system is the cement grinding system. People have paid much attention to the kiln before, but I believe people will pay more and more attention to the grinding system.
1. Current situation
of domestic cement grinding From the perspective of cement grinding system configuration, there are mainly vertical mill (vertical mill final grinding, vertical mill + ball mill), roller press (roller press + ball mill, roller press final grinding), etc. In a more detailed view, it is mainly the double independent powder selection system of roller press and ball mill; the common powder selection system of roller press and ball mill; the material selection and roughing of roller press system; the proportion of semi-finished products of material bed grinding system; the open flow, circular flow and switching of ball mill, etc. Each of
these powder separation systems has its own characteristics, and the cement industry in Southeast Asia, the Middle East and Africa is also following the pace of China's cement development.
In GB16780-2021, the power consumption of cement preparation sections at all levels is also required in the energy consumption quota per unit product. The optimal level of power consumption in the
cement preparation section is 22-24 kWh/t, but this has certain special conditions. At present, domestic cement grinding enterprises with three-level energy consumption account for 51%, two-level energy consumption accounts for 21%, one-level energy consumption accounts for 18%, and enterprises with non-three-level energy consumption accounts for 10%.
2. Evaluation
of energy saving and consumption reduction of cement grinding system The evaluation path of cement grinding system mainly includes three aspects: raw material & product, system & configuration and production & management.
Raw material & product: clinker source & quality, admixture variety & moisture, system capacity, finished product control index (fineness), cement production variety.
System & & configuration: features of grinding system, configuration of acting system, configuration of powder separation system, adoption of high-efficiency equipment, technical transformation & & new construction.
Production & & management: existing problems in production, central control operation screen, operation and management space, automation & & intelligent configuration, future positioning. In terms of the
work system, the main points that can be concerned are: the main contributor of power consumption; the installed power ratio of the working equipment; the material throughput of the roller press & the material throughput quality; the accuracy of the feeding granularity control of the working equipment; and the relative stability of the production varieties. In terms of the powder
selection system, the main points that can be paid attention to are: the guarantee of stable working conditions; not restricted by the energy consumption; the matching degree with the process system; the reasonable concentration of powder selection & the high efficiency of powder selection; the accuracy of the particle size range of powder selection; the adaptability of cement variety and operation mode switching; meeting the needs of fineness adjustment; the ability to resist wear. For the
fan system, the main points that can be concerned are: not restricted by energy consumption; wider range of high efficiency; higher operating efficiency; variable frequency speed regulation configuration; influence of system design (wear, vibration, pipeline); fan form (single suction, double suction, air intake form).
Process measuring points are the basis of intelligence, which can reduce the influence of human factors and management factors, improve the stability of working conditions and reduce the energy consumption of the system.
In addition, the installed power ratio of circular flow and open flow of the ball mill is 1.12, and the function of circular flow is not to increase production and reduce consumption; the installed power ratio of the roller press and mill is 1-1.5, and the grinding efficiency of the material bed is the guarantee of the system output and energy consumption; Fan installed power ratio: 13-20%, fan energy consumption is the embodiment of fine design + management level + equipment manufacturing. The impacts of
clinker on the cement grinding system are as follows:
III.
The relevant policies have also made detailed index requirements for the power consumption of the cement preparation section:
the cement industry is one of the key industries to achieve carbon neutrality. Carbon emissions of cement industry account for about 80% of the total carbon emissions of building materials industry, which is the key area of carbon emissions of building materials industry. Measures to reduce carbon emission in cement industry mainly include using alternative fuels, improving energy efficiency, carbon dioxide capture, storage and utilization, etc. Cement grinding will become one of the main directions of low carbon emission in cement industry in a short time, especially in optimizing the utilization coefficient of clinker, so the energy-saving technology of cement grinding should be more targeted.
Finally, the ultimate goal of cement industry development is to cross the life cycle, occupy the commanding heights, seize the ecological niche and find the breakthrough point.
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