How does the first "lighthouse factory" in the global special steel industry reduce carbon emissions? Carbon visit

Interface News Reporter | Banker key

The digital intelligence center building in the Xingcheng Special Steel Plant area can be called the brain of this steel factory. Located on the second floor of the building, the operation control center has a huge display screen showing the whole process of the factory from raw material dock, ironmaking, steelmaking to steel rolling, and you can understand the real-time data of each production link.

Xingcheng Special Steel is located in Jiangyin City, Jiangsu Province, and is a subsidiary of CITIC Pacific Special Steel Group Co., Ltd. (hereinafter referred to as CITIC Special Steel,000708.SZ) its largest steel mill,The factory has a history of 30 years, with an annual production capacity of 6.9 million tons of special steel. Compared with ordinary steel, special steel products have higher requirements for quality, performance and stability, accounting for only about 10% of the total domestic steel output.

The World Economic Forum recently announcedA list of 21 new "lighthouse factories".Xingcheng Special Steel is among them, and it has become the first "lighthouse factory" in the global special steel industry.

Launched in 2018, the Lighthouse Awards aim to select exemplary digital manufacturing demonstrators from the global manufacturing industry. Up to now, the number of "lighthouse factories" in the world has reached 153, including 6 in the steel industry, and the steel factories under China Baowu and Tata Steel have also been selected.

In 2020, Xingcheng Special Steel established the goal of creating a "lighthouse factory" by 2025, and has invested more than 500 million yuan since then to promote the construction of a number of intelligent manufacturing projects.

The carbon emissions of steel mills have been decreasing year by year, which is one of the results of these investments, and Xingcheng Special Steel's carbon emissions per ton of steel in 2022 have decreased by 10.47% compared with 2020.

The increasingly stringent carbon emission policies at home and abroad are an important factor driving Xingcheng Special Steel's carbon reduction. The national carbon market was launched in 2021, and the power generation sector is the first to be included in the regulation, and the high-emitting steel industry is expected to be included in the near future. Enterprises included in the national carbon market, if their carbon emissions are higher than the free allocation, must make up the gap by purchasing allowances, etc., and the current carbon allowance price in the national carbon market is about 70 yuan/ton.

The EU's Carbon Border Adjustment Mechanism (CBAM) has also launched a trial operation this year, which will impose additional "carbon tariffs" on specific products such as steel and cement imported from abroad.

Xinhua Daily reported that in 2022, Xingcheng Special Steel exported 155,000 tons of steel to the European Union, accounting for about 20% of its total exports. From 2026 onwards, if the carbon price of steel production is lower than that of the EU carbon market, it will be necessary to purchase a CBAM certificate to make up the difference. Based on the average carbon emission of Xingcheng Special Steel per ton of steel of 2 tons, and the carbon price of the EU carbon market is 68 euros/ton (about 532 yuan/ton), the cost of exporting each ton of steel to the EU will increase by up to 136 euros (about 1064 yuan).

The "black box transparency" of blast furnace is a key project for Xingcheng Special Steel to reduce carbon emissions in the production process.

Xingcheng Special Steel has three blast furnaces, and these steel buildings erected in the C position of the steel mill are an important process of steel smelting, with a height of 100 meters, and it is also the largest single reaction vessel in the steel mill. Ore, coke, pulverized coal, and hot air undergo redox reactions in this huge vessel at high temperature and high pressure, and finally smelt into molten iron.

About 70% of carbon emissions from steel production come from the ironmaking process, which is a major emitter of factories.

The temperature in the blast furnace usually exceeds 1500 degrees Celsius, and there is no equipment that can directly collect data in the blast furnace, which is like an invisible and intangible "black box", which has long been highly dependent on the experience of the operator. The analysis of the operation in the furnace is therefore difficult.

Li Hongkai, an expert from the Ministry of Intelligence and Information Technology of Xingcheng Special Steel, told Jiemian News that the so-called "black box transparency" of the blast furnace is to realize the all-round simulation of the blast furnace by using hundreds of metallurgical mechanism models and combining artificial intelligence, so as to understand the air flow in the furnace, the movement of the charge, the slag hanging on the furnace wall and other information, and get rid of the previous state of relying on experience to make iron and blind people touching the elephant.

A series of complex chemical reactions are involved in the blast furnace, and the coexistence of liquid, solid, and mixed mixed states in the furnace makes the model calculation involve thousands of variables, and the calculation is very complex. At the same time, the instability of ore, coke and other raw materials also brings considerable challenges to the all-round simulation of blast furnaces.

The "black box transparency" technical scheme of the No. 1 and No. 2 blast furnaces of the factory was jointly developed by Xingcheng Special Steel and Beijing Zhiye Interconnection, and the technical scheme and project implementation of the No. 3 blast furnace were completed by Xingcheng Special Steel independently, and have been put into use.

"By controlling the relevant parameters, it is possible to achieve stable production of the blast furnace and an optimal state of energy consumption." Li Hongkai explained. The "black box transparency" technology of blast furnace has been applied to Qingdao Special Steel, Daye Special Steel and other iron and steel plants under CITIC Special Steel, and external enterprises such as Baotou Iron and Steel and Jiuquan Iron and Steel are also using this technology.

On the basis of the "black box transparency" of the blast furnace, Xingcheng Special Steel has launched an unattended hot blast furnace intelligent firing system. The hot blast furnace is a blast equipment for blast furnace ironmaking, and its working principle is to continuously obtain high-temperature hot air through the combustion of gas.

This system collects data such as calorific value, temperature, and composition of gas, and automatically controls the rhythm of the furnace with the help of algorithms, which improves the stability of the blast furnace air temperature and reduces gas consumption.

According to Xingcheng Special Steel's statistics, after the use of this system, the total gas consumption of the plant's three blast furnaces decreased by about 100 million cubic meters in 2022, which is equivalent to a reduction of 100,000 tons of carbon emissions.

In addition to direct carbon reduction in the production process, comprehensive energy utilization is another important means of carbon reduction in this "lighthouse factory".

The energy management system launched by Xingcheng Special Steel in 2021 has collected energy metering information from 11,000 points in the whole plant and carried out in-depth application based on these data. One of these applications is gas forecasting and artificial intelligence (AI) scheduling.

Coal gas is a by-product of blast furnace smelting, and in addition to being used in blast furnace hot blast furnaces, it can also be used as a substitute for natural gas in other production links such as steel rolling and power generation in factories.

However, due to the large fluctuations in blast furnace gas output and consumption, it is difficult to achieve an overall balance between gas production and use through manual scheduling. In the event that an equilibrium cannot be achieved, the plant needs to empty the surplus blast furnace gas, which is called gas release in the industry.

Wang Yongjian, deputy general manager of Xingcheng Special Steel, told Jiemian News that combined with the production situation of each process, the artificial intelligence system can conduct a comprehensive analysis, predict the gas balance after one hour, and automatically generate predictive suggestions to improve the gas utilization rate.

According to Xingcheng Special Steel's statistics, after the application was put into operation, the overall gas emission volume of the plant dropped to 9,869,700 cubic meters in 2022, a decrease of 89.94% compared with 2020.

Li Hongkai said that if these gas by-products from the blast furnace production process are not used efficiently, it will lead to a further increase in the plant's carbon emissions.