What is the “black technology” behind green steel production?

Editor's Note

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Under the blue sky and white clouds, the once billowing black smoke is no longer there, replaced by green trees and fresh air. The steel industry, which is regarded by the public as a synonym for high energy consumption and high pollution, is undergoing a profound green revolution.

In recent years, steel enterprises have continuously implemented the concept of green development in every production link through technological innovation and environmental protection practices, and have made many breakthroughs. Recently, the reporter visited Baosteel Meishan Iron and Steel Co., Ltd. (hereinafter referred to as "Meishan Steel") to reveal the "black technology" behind its green production.

Introduction of biotechnology: Advanced application of "DDS biological desulfurization technology"

As a by-product of the steel production process, coke oven gas often contains a large amount of sulfide. If it is not treated, it will have a serious impact on the environment. Meishan Steel adopts the "DDS biological desulfurization technology", which uses microorganisms to convert sulfides into harmless substances, thereby achieving effective purification of waste gas. Compared with traditional chemical desulfurization methods, biological desulfurization technology is more environmentally friendly. Not only does it not produce secondary pollution, but it can also convert sulfides into usable sulfur resources. It is an environmentally friendly and economical desulfurization method. In October 2022, Meishan Steel put into use the DDS biological desulfurization device in the coking industry in China for the first time. The device further optimized the coke oven gas desulfurization process by using the "coke oven gas DDS biological desulfurization technology", opening up new ways for environmental protection and resource conservation.

The exterior view of the coke oven gas desulfurization equipment. Photo provided by Meishan Iron and Steel

Intelligent and automated management: innovative breakthrough in “unmanned steel casting technology”

In the continuous casting and steel pouring process, Meishan Iron and Steel, as the "first person to try it", took the lead in realizing the application of "unmanned steel pouring technology" in the industry. This technology can accurately monitor and automatically adjust key parameters in the production process to ensure that the continuous pouring of molten steel is both efficient and stable. In response to the three production accidents that may occur on site, namely overflow, leakage and interruption, Meishan Iron and Steel has successfully developed the first domestic automatic handling process technology model for continuous casting and pouring anomalies. Through intelligent identification and automatic handling of abnormal situations in production, the misjudgment rate of abnormal continuous casting accidents has been reduced to zero, and the normal utilization rate of the system has exceeded 95%. The breakthrough of this technology has not only effectively reduced energy consumption and production costs, but also significantly improved the working environment of workers, helping the steel manufacturing industry to move towards intelligent and green development.

Steelmaking and continuous casting platform (unmanned steel pouring). Photo courtesy of Meishan Steel

Practice of circular economy: Blast furnace top pressure equalization gas recovery process

In the blast furnace production process, the main product is molten iron, while gas and slag are by-products. Top gas is a high calorific value by-product that was often wasted in the past. At present, the steel industry has basically achieved full recovery of blast furnace gas, but a small amount of gas is still lost at the top of the blast furnace and has not been effectively collected. Meishan Iron and Steel uses the "blast furnace top equalizing pressure recovery process" to capture and convert the top gas, achieving true 100% recovery of blast furnace top gas.

Exterior view of the blast furnace top pressure-equalizing gas recovery process equipment. Photo courtesy of Meishan Iron and Steel

With the continuous advancement of technology and the deepening of the concept of green manufacturing, the steel industry is gradually bidding farewell to its traditional image of high pollution and high energy consumption and moving towards a new stage of sustainable development. From biological desulfurization to waste heat recovery, from intelligent management to unmanned operation, every innovation of steel companies is an important step towards a green future.

Review: Senior Engineers Han Jiayou, Yang Xiaoqing, Rao Gang, Zhang Huanxiu, Guan Ping