Sinosteel uses NI products to minimize the impact ON the environment, increase production capacity and reduce costs.
“Our solutions can significantly improve personnel safety, save energy, reduce CO2 emissions, and increase production.”
—— Wang Zhizhong, China Iron and Steel Corporation
challenge:
In order to improve the production capacity of the sintering plant, we need to adopt an effective air leakage detection method to detect the amount of air leakage and the source of air leakage, and analyze the air leakage data as the basis for regular maintenance and replacement of the sintering trolley.
solution:
Using a sound pressure microphone, based on air noise and NI software and hardware, a detection system was developed to quickly detect the air leakage of the trolley, so as to achieve the goals of energy saving, carbon reduction, production increase and quality improvement.
author:
Wang Zhizhong – China Iron and Steel Corporation
Dr. Wang Chih-Chung – China Steel Corporation (Taiwan)
Ironmaking plants mainly provide molten iron and raw materials for steelmaking, while coke ovens and sintering plants supply ironmaking raw materials, coke and sinter, respectively, for blast furnace ironmaking. Sinter plants mainly produce sinter, which is the raw material for blast furnace ironmaking. The main production process is to mix various iron ore (Iron Ore), flux (Flux such as limestone), coke shavings (Coke Breeze) and other raw materials according to the specified proportion, after mixing and granulating with a uniform mixing drum, send it to the Sinter plant for calcination. After the sintered sinter is crushed and screened, the 5-50mm qualified sinter will be sent to the blast furnace as the main raw material for iron making.
Difficulties facing sinter plants
In the sintering process, an important indicator to detect the quality of the sintering condition is the sintering air permeability (JPU). The air permeability during the generation process depends on the ventilation volume of the exhaust system. The sintering machine is the part of the exhaust system that directly contacts the raw materials and is most prone to air leakage.
The structure of the sintering machine consists of multiple sintering trolleys, and the sealing devices at the front and rear of each trolley are in contact with the bottom of the trolley beam and the hard metal plate on the side of the bellows. In order to prevent friction with the sharp sintered material, resulting in scratches and air leakage, a certain expansion space must be left during the sintering process. Once the sintering machine trolley leaks, it will lead to a reduction in the ventilation rate, which will directly make it difficult for particles to form and reduce the output of sintered ore.
The intact sintering trolley has no air leakage, the fan burden of the exhaust system is lower, and the electricity consumption is less. For the sintering trolley with air leakage, the fan must maintain a certain amount of ventilation at a higher speed. At this time, the motor driving the fan will provide a higher driving current, thus consuming more power. In order to improve the production capacity of the sintering plant, we need to adopt an effective air leakage detection method to detect the amount of air leakage and the source of air leakage, and analyze the air leakage data as the basis for regular maintenance and replacement of the sintering trolley.
Conventional leak detection methods
In the past, we relied on manpower to test during the operation of the sintering machine. The personnel must be exposed to high dust and high noise (about 90-110 decibels) environment for a long time, and use their own eyesight and hearing to make judgments. However, the source of air leakage may be various parts such as the material surface or the trolley itself, and it is difficult for manpower to track the place where the air leakage occurs.
In the past, we relied on manpower to test during the operation of the sintering machine. The personnel must be exposed to high dust and high noise (about 90-110 decibels) environment for a long time, and use their own eyesight and hearing to make judgments. However, the source of air leakage may be various parts such as the material surface or the trolley itself, and it is difficult for manpower to track the place where the air leakage occurs.
In the past, we relied on manpower to test during the operation of the sintering machine. The personnel must be exposed to high dust and high noise (about 90-110 decibels) environment for a long time, and use their own eyesight and hearing to make judgments. However, the source of air leakage may be various parts such as the material surface or the trolley itself, and it is difficult for manpower to track the place where the air leakage occurs.
Why choose NI products
The value of IT lies in the ability to qualitatively and quantitatively analyze problems to achieve the purpose of visualizing problems. When building a sintering trolley for air leakage, we must know how to identify air leakage, how to identify different air leakage patterns and quantify their impact, and how to choose the trolley that requires the most maintenance based on computational maintenance and work ability considerations.
When choosing a signal acquisition and analysis instrument platform, we need to consider factors such as the convenience of the platform programming language, computing power, hardware communication, and reliability under long-term use. NI has launched a variety of reliable modular hardware for various measurement requirements. With NI LabVIEW and various function toolboxes, flexible and highly integrated customized systems can be rapidly developed, which can fully meet the above considerations. The system combines sound array, RFID technology and NI-PXI platform to provide a good solution for automatic air leak testing system.
Solution introduction
We use a sound pressure microphone to develop the optimal detection method based on air noise to detect the air leakage of the trolley. At the same time, the array structure is used to comprehensively detect the air leakage of each part of the trolley, and then the NI PXI chassis, PXI-8106 embedded controller and PXI-4472 dynamic data acquisition module are used for data acquisition. We use LabVIEW as a development platform to accelerate detection and verification of the feasibility of the method and to check the stability of the system. Provide real-time air leakage information of trolleys, and achieve the goals of energy saving, carbon reduction, production increase and quality improvement through proper maintenance.
Test Results
We put the developed automatic test system in Sinosteel No. 1 sintering plant to test and record the air leakage of each trolley. According to the measurement results, we overhauled the 20 trolleys with the most serious air leakage, and obtained good results. The average output before the repair was 6205 tons/day, and the average output after the repair was 6292 tons/day, the output increased by about 87 tons/day, and the average yield increased by about 0.65%.
In addition to the regular maintenance time, the sintering trolley system operates continuously 24 hours a day. Therefore, we only repaired 20 trolleys, and the output has increased significantly. Under the fixed output target, reducing the air leakage of the sintering trolley and trying to increase the effective air volume passing through the sintering trolley can reduce the burden of driving the fan of the sintering trolley, thereby reducing the driving current of the fan motor.
The electricity consumption before the improvement is 3,282 kW/h, and the electricity consumption after the improvement is about 3,245 kW/h, which saves about NT$540,000 in electricity bills per year on average. In the overall sintering process, 0.637 kilograms of carbon dioxide will be generated per kilowatt-hour of electricity. After using this system, about 198 tons of carbon dioxide emissions will be reduced every year. In addition, low air leakage will improve the yield of sinter. Fewer sinters must be recovered due to unqualified particle sizes, reducing recovery costs and avoiding wasted energy from repeated sintering.
The electricity consumption before the improvement is 3,282 kW/h, and the electricity consumption after the improvement is about 3,245 kW/h, which saves about NT$540,000 in electricity bills per year on average. In the overall sintering process, 0.637 kilograms of carbon dioxide will be generated per kilowatt-hour of electricity. After using this system, about 198 tons of carbon dioxide emissions will be reduced every year. In addition, low air leakage will improve the yield of sinter. Fewer sinters must be recovered due to unqualified particle sizes, reducing recovery costs and avoiding wasted energy from repeated sintering.
The benefits of choosing NI hardware and software
In this program, NI provides consulting and support for system development, helping us to accelerate the development and verification of the feasibility of the entire green energy engineering program, and will introduce this technology for use in other sintering plants in the future. Our solutions can significantly improve personnel safety, save energy, reduce CO2 emissions and increase production.
The Links: LTM150XH-L06 JS225010