Design of Thermal Utilization of Billet
Billet is a semifinished product in steel smelting process. It is initially a heated and rolled 70-125mm sized piece of crude steel. The components of a steel billet are mainly C, Si, Mn and P,S. According to the different production process and requirements, the purpose of each billet is also different. In the process of steel melting, although the steel billet has reached a certain production standard, its own energy consumption is too large and a lot of heat energy is wasted. The utilization of the heat energy contained in the steel billet has become the main area that needs to be explored and improved in the steel smelting process.
From the standpoint of heat utilization, the application of the heat energy of billets is mainly concentrated in three aspects. The first is to recycle and use billet heat energy in the upstream process of steel, mainly including billet reheating furnace and ladle furnace, charging vehicle, etc. During the descaling process of billets, the heat-generating energy needs to be recycled. The second is to use heat energy to improve the heat utilization rate, such as furnace internal heat recycling technology, billet tail-end heat energy recovery, etc. The third is to use billet heat energy to generate other supports, such as power generation and hot water supply, etc.
In the process of billet utilization of heat energy, in combination with the actual situation and circumstance, different conditions and scope of utilization should be taken, and the feasible methods and strategies should be selected. The reasonable combination of the two, combined with the reasonable control of the heat utilization rate of steel billet, can reduce the energy consumption and waste of the entire process.
In order to improve the utilization rate of billet and reduce the loss, it is necessary to first improve the production equipment. The production process of billets should strive to reduce the heat storage and loss rate of the materials, reduce the amount of energy consumed during the heating process, improve the effectiveness of convective heat transfer, as well as reduce the rate of heat loss in furnace wall. At the same time, the production process should use advanced energy-saving technology and equipment, such as the adoption of recuperative heat exchange technology and direct blast technology, in order to achieve the purpose of energy saving.
Second, from the perspective of the choice of auxiliary materials, more efficient and energy-saving refractories should be selected, and the insulation measures for production equipment should be strengthened. Heat energy is usually accumulated faster and lost later during steelmaking process, substances with good heat accumulation and insulation effects should be used to improve the effective heat exchange area and reduce the heat loss rate.
Third, heating furnace should be optimized and improved. In order to improve the heat utilization efficiency and reduce energy consumption, the heating furnace adopted should have both high thermal efficiency and low environmental pollution. The installation of heat measurement and digital control system should also be done to adjust the output of the furnace reasonably.
Fourth, the billet tail-end heat energy recovery technology should be adopted. After the hot billet is cut into pieces, each piece of the billet is poured out from the mouth of the cut machine, and the remaining thermal energy should be recovered for production applications.
Finally, energy management and other improved measures should be further strengthened. With the help of computer monitoring and management system, real-time monitoring of labor, technology and equipment are conducted, and effective energy feedback is formed. The key performance indicators (KPI) of each process are optimized and adjusted, in order to promote a comprehensive energy-saving and heat utilization process.
To summarize, billet thermal energy utilization is a key part of realizing energy conservation and emission reduction in the steel-making process. The optimization and improvement of steel billet thermal energy utilization can reduce the cost of steel-making, improve the efficiency of steel-making, and reduce the environmental pollution caused by legacy energy sources.
