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Cutting Energy Costs in Steel Casting Facilities

Researchers at Missouri S&T analyze methods for improving melting efficiency. A MODERN CASTING STAFF REPORT

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he high temperatures required to melt steel result in significantly higher energy losses in comparison with melting

other cast alloys. Te energy costs associ- ated with heat losses during melting are significantly higher for steel casting facilities than for those melting other alloys. Today’s steel casting facilities use induction furnaces (IF) and electric arc furnaces (EAF) to melt steel. Siddhartha Biswas, Kent Pea-

slee and Simon Lekakh of Missouri University of Science & Technology, Rolla, Mo., conducted a benchmark- ing survey on current energy use among U.S. steel casting facilities. Tey investigated opportunities for energy improvement through a series of industrial trials involving chemical energy and ladle practice development.

Question What best practices and methods

can improve energy efficiency in steel casting operations?

Background Furnace capacity, power

supply, age of equipment, rate of production, melt- ing schedule and operating

practice all have major influences on energy consumption. A study of 19 North American steel casting facilities included a combination of historical data and industrial measurements on the type of melting equipment, refrac- tory practices (Fig. 1), energy use and ladle practices. (See Tables 1, 2 and 3.) A multiple regression analysis

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using commercially available statistics software allowed the researchers to evaluate the influence of the melting furnace (type, size, age and transformer power) and operating parameters such as tap temperature, tap to tap time and furnace productivity on the energy consumption for melting steel. Successful energy management in

steel casting facilities is difficult with- out monitoring energy consumption. Unfortunately, this is an area where the steel casting industry is poorly equipped. Only 38% of EAFs and 15% of IFs in operation are equipped with electric meters for monitoring electric

ADDING IT ALL UP Breaking down the latest research is as easy as 1-2-3.

“Increasing Melting Energy Efficiency in Steel Foundries” Siddhartha Biswas, Kent Peaslee and Simon Lekakh of Missouri University of Science & Technology, Rolla, Mo.


Background—Steel casting is one of the most energy intensive industries. Increasing concerns over volatile energy costs and carbon dioxide emissions have pushed metalcasters to improve melting efficiency and decrease their electrical energy consumption. Researchers at Missouri University of Sci- ence & Technology, Rolla, Mo., spent five years studying this topic under a grant from the U. S. Department of Energy’s “Energy Saving Melting and

Revert Reduction Technology” (“Energy SMARRT”) program. Procedure—Te researchers combined statistical analysis of industrial mea- surements (thermocouple, infrared camera) and operating data with thermo- dynamic and computational fluid dynamics (CFD) modeling to investigate

best industrial practices and opportunities to improve energy efficiency. Results and Conclusions—Industrial trials investigated improvements in melting efficiency and productivity using supplemental chemical energy through additions of SiC and oxyfuel burners in electric arc furnaces. New ladle designs and practices were investigated to reduce energy losses in the ladle. A dynamic model of heat losses in the ladle from furnace tap to mold pouring is being developed to aid metalcasters in energy optimization.

February 2013 MODERN CASTING | 47

consumption. More than one third of the plants surveyed have no equipment for monitoring their energy consump- tion during steel melting. Multiple regression analyses

determined how operating practice variables and equipment type influence the energy consumption in kWh/ton for melting steel. Te analysis showed the following independent vari- ables had an influence on the energy consumption for melting steel (from strong to weak influence): • Increasing “tap temperature” increased energy consumption (strong influence).

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