Following the coal and coke recipe is key at R&D

12.18.2019

Metallurgical coal is a natural fossil fuel used in the steelmaking process. It is ultimately baked, turning into coke, which is an essential raw material used in blast furnaces as a fuel and a reducing agent for liquid metal production.  

“Coke quality is the most important factor for operating the blast furnaces,” said Bhaskar Kodukula, program leader, coal and coke making, ArcelorMittal USA.  

ArcelorMittal acquires metallurgical coal required for cokemaking from companies in North America as well as ArcelorMittal Princeton in West Virginia. ArcelorMittal’s current blast furnace operations at Indiana Harbor, Burns Harbor, and Cleveland consume approximately 4 MT of coke. 

“Our main objective at Burns Harbor coke plant has not changed over the years. The objective is to produce the highest quality, lowest cost coke that meets blast furnace quality and production requirements without sacrificing the longevity of the coke oven battery facility and assets,” said Timothy Candiano, division manager, coke producing, ArcelorMittal Burns Harbor. 

Coal selection and blend design for USA operations is a systematic activity comprised of members from operations, R&D, procurement and logistics departments.  

The coal to coke process from beginning to end

Global R&D in East Chicago plays an integral role in supporting the coke plant by ensuring the quality and cost-savings are impeccable by developing coal blending models, along with developing and adopting novel technologies to maintain ArcelorMittal’s competitive edge.   

Coal piles at Burns Harbor

Due to the coal mining and coal to coke conversion process, coke is one of the most expensive items in the cost structure of steel. Therefore, the coal blends designed at R&D are optimized according to total costs of ownership, such as coal price and transportation. R&D evaluates the potential of new coals through blend design, systematic characterization and quality, and oven safety testing in a movable wall oven (MWO). The MWO test identifies the pressure a blend would generate on the oven walls in the coke oven battery. This is extremely useful as it indicates the potential for causing any operational issue or damage to the battery. It also provides an accurate estimation of the quality of coke that will be produced in an industrial blend as well as the impact on the coke plant and blast furnace productivity, and the total cost of pig iron. 

Regarding blend design, R&D has established methods for investigating the use of special blend additives, which would enhance the quality and enable usage of cheaper quality coals in the blends. This year, R&D minimized the blend cost by reducing the utilization of expensive coals without compromising quality and operational safety. 

“In 2018, the coal industry started changing. As with competition, we could not keep up with the past year’s blend designs because of rising costs and the risk of disruption due to suppliers’ bankruptcies. Therefore, we shifted our focus on blend designs,” added Candiano. “We arrived at a high-volume low-volume mix that could reduce the manufacturing cost and improve quality. After several months of reviewing the opportunity and many tests, a modified version was agreed upon.” 

This activity has saved several million dollars in coal procurement for 2020. It also gives procurement the opportunity to strengthen the relationship with strategic suppliers and enhance sustainability. 

Another sustainable initiative in the works at Global R&D in East Chicago is the development of coal moisture control technologies, which may reduce overall cokemaking costs and our CO2 footprint.  

“Cokemaking 4.0” is another new R&D program currently being piloted at ArcelorMittal. If this initiative launches, process automation and controls using artificial intelligence would allow for real-time optimization on blend preparation, battery heating and controls with coal blend quality change.  

“High quality and consistency, yield maximization, energy savings and better environmental compliance are some of the benefits anticipated from this initiative,” noted Kodukula.  

Whether baking brownies or finding the perfect blend design, precision and innovation are key.  

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