Environment

Energy Management3.2.3

By developing technologies that reflect the environmental aspects of steelmaking as an energy-intensive industry, Hyundai Steel is striving to efficiently manage its energy consumption while reducing GHG emissions.

Application of a Temperature-optimization System for Heating Furnaces

Heating furnaces need to reach the temperatures required by rolling machines according to the specifications of particular products. However, heating furnaces have been operated manually thus far by operators drawing on their previous experiences, hence precise temperatures were hard to measure and this resulted in energy losses. Hyundai Steel has therefore developed a heating furnace optimization system that enables precise energy input through consideration of key operational variables, measuring material temperatures in real time and identifying target extraction temperatures. In 2020, we equipped the system with a required temperature estimation model and an optimal pattern identification model, and are currently developing a model to forecast target extraction temperatures. In 2021, Hyundai Steel plans to apply this forecasting model, and through the heating furnace optimization system, reduce risk in the rolling and roughing processes while improving our fuel costs.

Stabilization of Heat Generation Measurement for Coke Oven Fuel

In a coke oven, if the thermometer indicates non-ignition or another abnormal reading, this causes a risk of input heat flux due to operation at a fixed MG(mixed gas) ratio1). To address this, Hyundai Steel has developed a dual system for caloric power control. In the event of caloric power flux, this system is used in place of the energy center's caloric value. Since applying the system, the stabilization of input MG caloric power has stabilized our plants' oven temperatures and caloric consumption, which is expected to lead to cost savings. Hyundai Steel will continue to upgrade the system and analyze the application effect to stabilize its heating value.
  • 1) Ratio of COG in mixed gas(mixture of BFG and COG)

Optimization of Hot Blast Stove Efficiency

Hyundai Steel's hot blast stoves are equipped with a facility to recover waste heat from gas. This facility consists of separate systems that recover waste heat from the air side and from the fuel side. By optimizing the flow of diverted gas on the air and fuel sides, Hyundai Steel's Technology Team has increased the amount of heat recovered. Furthermore, since 2019, we optimized the divergence of heat recovery gas and deployed the system on site. This is currently applied in blast furnaces 1 and 3, and with plans to introduce it to blast furnace 2 by March 2021. Through these advancements, we have secured our own combustion control model and technology to optimize divergence in heat recovery, leading to improved efficiencies in hot blast stoves. Going forward, we plan to focus on developing an automatic tuning model for hot blast stoves and upgrade our hot blast stove combustion air control system.

System for Heat Recovery from Water Coolant in Heating Furnaces

The system used for reheating materials before rolling consumes a great deal of gas fuel, and the process that produces the most GHG emissions. To cool the walking beams2) and skids3) that transfer material inside the furnace, water coolant is used, resulting in heat loss accounting for 10~15% of input heat. Therefore, in 2020, Hyundai Steel introduced an Evaporating Cooling System(ECS) at the large rolling heating furnace in our Incheon Steelworks, which recovers heat from the coolant as steam. As the highly pressurized, high-temperature water passes through the heating furnace and is evaporated, this system absorbs heat and cools the furnace, allowing the heat generated in this process to be reused as steam. Having introduced the ECS, we expect to create profits of KRW 1.8 billion a year by supplying a heat source to the local community.
  • 2) Method of movement and continuous operation for materials to be heated by hydraulic drive
  • 3) Conveyor for steel in the furnace and on the cooling bed
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