Saving energy for American industry is part of the solution.
Because industry consumes approximately one-third of the energy used in the United States, researchers at Oak Ridge National Laboratory are actively developing novel materials and technologies to reduce industry's consumption of oil, natural gas and electricity produced by coal combustion. The governor of Ohio has endorsed their efforts.
In each of the past two years, ORNL received an Ohio Governor's Award for research that enabled Ohio industrial firms to save energy and increase profits. In one case ORNL researchers and industrial partners developed an aluminum-bronze copper alloy to replace traditional carbon steel in the "skirt" portion of large furnaces used for making steel at Republic Engineered Products' plant in Lorain, Ohio.
Unlike the conventional material, the new alloy in a skirt subjected to 20 months of service did not accumulate residues from the smelting process and operated without leaking. While a traditional carbon steel skirt might have required as many as 50 shutdowns for maintenance over 20 months, the newly designed equipment required none. The lifetime for a skirt made of the new alloy is expected to be six times that of the skirt fabricated from the conventional material.
Reduced maintenance on the skirt has saved Republic Engineered Products 5.3 billion BTUs of energy per year, valued at $39,750. The company expects to save an additional 4 billion BTUs per year, or $30,000, after installing other components fabricated from the new alloy. The increase in steel production made possible by fewer shutdowns is expected to generate an additional $12 million annually for the company. For this work performed through a $1 million grant from the Industrial Technologies steel program in the Department of Energy's Office of Energy Efficiency and Renewable Energy, ORNL's Vinod Sikka and his team in the Materials Science and Technology Division shared the Ohio Governor's Award for Energy Efficiency in 2006.
Through assistance from ORNL and its partners, Queen City Forging Co. in Cincinnati is now producing high-quality forged aluminum rotors for turbochargers used in truck diesel engines. Three years ago, U.S. diesel engine companies were installing turbochargers made using heavier titanium rotors purchased abroad. ORNL's Craig Blue and his colleagues developed for Queen City Forging a new hybrid infrared heating system that rapidly and uniformly heats aluminum alloy billets before forging. Compared with the company's gas-fired convection and induction furnaces, rapid infrared heating is more than twice as efficient, uses one-third as much energy, processes aluminum at least four times faster and produces billets that last twice as long. The increased throughput and improved consistency of the product's mechanical properties reduced the cost by 40 to 50%.
In 2005 Gov. Bob Taft presented Blue and ORNL's partners with the Ohio Governor's Emerging Technology Award for the "Advanced Heating System for High-Performance Aluminum Forgings," a recipient of a 2004 R&D 100 Award from R&D magazine as a top technology of that year. ORNL's partners were Northeastern University, Queen City Forging Co., Komtek, Forging Industry Association and Infrared Heating Technologies. Blue says that the heating technology is a winner for not only industrial energy efficiency but also transportation energy efficiency because replacing the titanium rotor with the lighter aluminum rotor improves diesel vehicle fuel economy.
In the autumn of 2005, spikes in natural gas prices combined with fuel and electricity shortages resulting from Hurricane Katrina to threaten the productivity of U.S. industry. Energy Secretary Samuel Bodman responded by establishing the "Save Energy Now" initiative. The Department of Energy's Industrial Technologies Program called upon ORNL's BestPractices Support Team to support the effort. This team led by Tony Wright was asked to send qualified efficiency experts to 200 of America's most energy-intensive factories and advise on-site managers on how to conserve fuel and use energy more efficiently.
DOE's Energy Saving Teams exceeded the target and met the deadline. They conducted 200 energy savings assessments by the end of 2006. Because steam and processing heating consume about three-fourths of the energy used in large industrial plants, the teams focused on industrial steam systems and direct-fired process heating systems.
According to Wright, in each energy assessment a specialist worked with industrial plant leaders over three days. DOE software tools were used to quantify energy savings opportunities in targeted areas such as improving insulation, modifying steam turbine operation, recovering and reusing flue gas heat and installing an integrated cooling, heating and power system, which captures and uses waste heat.
"The amount of energy saved and the resulting cost savings identified in the completed assessments have been enormous," Wright says. "The value of the total potential plant energy savings identified is $494 million annually, or an average of $2.4 million for each of 200 plants assessed.
"The potential natural gas savings identified amounted to 52 trillion BTUs per year. This savings is equivalent to the natural gas consumed by 725,000 typical American homes."
Redesigning distillation for petrochemicals
In the chemical industry, distillation consumes more energy than any other chemical separations technology. To separate chemicals using distillation, the chemical industry burns natural gas while oil refineries combust oil or other hydrocarbon fuel.
DOE estimates potential energy savings of 53 trillion BTUs a year in the petrochemical industry from adoption of redesigned distillation columns for improved flow. This savings, valued at approximately $400 million a year, is based upon simulations using innovative software developed at ORNL. Called Graphical Structured Packing Interface (GraSPI), this software tool developed by Valmor de Almeida is a plug-in to accelerate modeling of distillation by FLUENT, a commercial computational fluid dynamics code available from ANSYS.
Industrial distillation to purify petrochemicals from a crude oil starting material is typically performed in large, vertical cylinders called distillation columns. Liquid flows down the column and gas flows up the column through metallic packing formed in complex geometries. Each distinct compound has a characteristic vapor pressure and boiling point, allowing separation by relative volatility. The liquid outlets at intervals up the column allow for the withdrawal of different chemicals. Products with the lowest boiling point exit from the top of the column and the heaviest leave at the bottom. The GraSPI software improves distillation flow simulations and guides changes in packing designs that could make column separations more efficient, resulting in purer products, reduced emissions and energy savings.
Wireless in the workplace
Since 1996 ORNL's Wayne Manges has been urging industry to install wireless technology to reduce energy use despite concerted opposition by some to wireless sensors. An early adopter was a nuclear power plant in Texas. Three companies are now demonstrating and evaluating wireless technology developed in a DOE program started after Manges organized a workshop at ORNL. The companies are Honeywell, for oil refineries and the petrochemical industry; Eaton, for electricity distribution and electric motors; and General Electric, for the paper industry.
"Wireless technology is safe, effective for controlling industrial processes, and relatively inexpensive," Manges says, noting that installation costs of wire in harsh industrial environments can range widely from $40 to $2,000 a foot.
Overheating of electric motors in industrial plants wastes energy while damaging motor parts. Although some motors can operate ten years before failing, most companies replace perfectly functioning electric motors every two years to avoid motor breakdowns. Some companies are installing wireless temperature and vibration sensors that detect early signs of motor failure and alert operators. Allowing motors to run longer reduces maintenance and downtime and results in greater productivity.—Carolyn Krause
Web site provided by Oak Ridge National Laboratory's Communications and External Relations