The amount of captive power generated using secondary energy resources is currently almost 3.5 times higher than in 1999. In 2019, the site was able to meet 65% of its electric power needs.

NLMK Lipetsk’s existing captive power generation facilities:

• 332 MW cogeneration plant (CGP).

• 150 MW recovery cogeneration plant (RCGP) complex. Blast furnace gas generated in the process of making pig iron is fed to the CGP and RCGP to generate power. The state-of-the-art RCGP complex was commissioned in 2011. The blast furnace gas from BF-7 serves as fuel for the cogeneration plant.

• 40 MW top-pressure recovery turbine (TRT) plant. NLMK has mastered the process of energy generation from excess blast furnace gas pressure at its top-pressure recovery turbine plant, which combines two TRT units. The first TRT unit, which uses gas produced by BF-7, was put into operation in 2015. The second TRT unit downstream of BF-6 was commissioned in 2016.

The first TRT unit, which uses gas produced by BF-7, was put into operation in 2015. The second TRT unit downstream of BF-6 was commissioned in 2016.

Principle of top-pressure recovery turbine (TRT) operation

The gas exits the blast furnaces at a pressure of about 2.5 atmospheres. The pressure needs to be reduced before sending it to the CGP. Previously, the excess pressure was lowered at the reduction unit, and this resource was wasted. With the commissioning of the new TRT units, the pressure energy from the blast furnace gas is used to generate electricity by rotating the turbine rotor and the generator. No fuel combustion is required for this power generation process. That is why the TRT energy generation technology is considered eco-friendly.

Prospects of developing secondary gas technologies for electric power generation

In 2019, NLMK Group launched a project to build a new 300 MW recovery cogeneration plant (RCGP-2). Blast furnace and basic oxygen furnace gases generated during pig iron and steel production will make up 75% of the fuel input for the plant.

Using these gases as fuel for energy and heat generation will enable a decrease in CO emissions by over 3,000 tonnes per year and in CO2 emissions by 650 tonnes per year.

The project’s uniqueness

The RCGP project is unique because it will be the first BOF gas capture and storage system in Russia. Currently, all BOF gas at NLMK Lipetsk is flared instead of being recovered. With the revamp of BOF off-gas ducts that is scheduled for completion in 2021, the capture and use of BOF gas as fuel is becoming a reality.

The BOF gas capture and recovery technology is successfully used by global steelmakers and is considered one of the world’s best practices in environmental impact management and energy efficiency improvement in steelmaking.

Once the project is implemented, NLMK Lipetsk will be able to cover 95% of its own energy needs.