Through Save Energy Now (SEN), the U.S. Department of Energy’s (DOE’s) Industrial Technologies Program (ITP) helps industrial plants operate more efficiently and profitably by identifying ways to reduce energy use in key industrial process systems. From its inception in 2006 to May 2008, 526 assessments have been performed around the country, identifying cost savings of over $750 million. Approximately $112 million in energy savings recommendations have been implemented, resulting in 74.1 trillion British thermal units (Btus) of natural gas savings.

In March 2006, an SEN assessment was conducted for Goodyear at the company’s tire plant in Union City, Tennessee. Founded in 1898, Goodyear is one of the world’s largest tire companies, with 70,000 employees and more than 60 tire plants in 26 countries. Goodyear develops, markets, and sells more than 80 different types of tires for a wide variety of vehicles. In 2006, the company posted net sales of $20.3 billion. The Union City plant opened in 1968 and employs approximately 2,800 workers.

The SEN assessment was performed by DOE Energy Expert Don Schmidt of Geos, LLC, who worked with two plant employees to analyze the plant’s steam system. As a qualified specialist in the use of DOE’s steam system assessment tool (SSAT) software, Schmidt installed the program on the employees’ computers and reviewed the data with them. This not only helped the plant team learn the software, but it also showed them how to analyze and identify natural gas savings opportunities in the plant’s steam system and apply those practices to other Goodyear facilities.

The steam system at the Union City plant is served by four dual-fueled (natural gas and No. 6 fuel oil) boilers. The plant uses more than 400,000 MMBtu (million Btu) of natural gas and 4 million gallons of No. 6 fuel oil annually. Steam is important for the Union City plant’s production because it is needed for critical applications, such as tire curing and processing. Because many of the steam traps are next to the plant’s presses, steam trap maintenance is critical to ensuring that the presses operate reliably.

The Goodyear plant has a longstanding energy management policy aggressively focused on maintaining steam traps and repairing leaks. Faced with rising energy costs and the need to remain competitive, plant employees had contemplated additional efficiency improvements to their steam and motor-driven systems. Plant associates had long suspected that their steam system could yield significant energy savings. The SEN assessment report added weight to concerns raised by the plant energy team.

Assessment Recommendations

Using the data collected in the SSAT software, the team identified three potential energy savings measures and evaluated each for technical and economic feasibility. After reviewing expected cost and energy savings and the associated payback periods, the team determined the following near- and medium-term opportunities.

Near-term opportunity

• Optimize Boiler Operation and Load Management Strategy—The steam load profile showed that the plant operated all four boilers at part load for redundancy purposes. In addition, two boilers were operating with excess flue gas oxygen levels, and the air inlet temperatures were unnecessarily hot. Careful analysis of the plant’s reliability requirements showed that the plant’s steam demand could be met by operating the large boiler and one of the smaller boilers at higher loads.

Medium-term opportunities

• Insulate Process Equipment—While much of the steam system, including the headers, was insulated, the plant’s tire presses were only partially insulated. The assessment calculated that the plant was losing approximately 1,500 pounds per hour (lbs/hr) of steam. It was recommended that the plant completely insulate the presses to reduce steam demand, which would lower steam system energy consumption. Annual energy savings were estimated at almost 23,000 MMBtu of natural gas and more than 224,000 gallons of No. 6 oil, with total annual cost savings of around $400,000.
• Recover Process Waste Heat—Due to contaminants from the production process, a significant quantity of condensate is unsuitable for return to the boiler. This condensate is diverted to a “hot well,” where it is cooled in a cooling tower and then used to cool other plant processes. The assessment showed that the condensate’s heat could be recovered using a heat exchanger to raise make-up water temperature, which would reduce the load on the boilers. Annual energy savings were estimated at 9,600 MMBtu of natural gas and 94,100 gallons of No. 6 oil. Estimated annual cost savings were approximately $176,000 per year.

If implemented, the total annual energy cost savings from both the near- and medium-term opportunities was estimated at more than $1 million.

Assessment Results

Goodyear’s Union City plant personnel began optimizing boiler operation and working on a load management strategy shortly after the assessment was completed. To optimize boiler operation, the employees adjusted the automation controls on all the boilers and reconfigured the forced draft fan inlets as specified in the assessment. This enabled them to operate the large boiler closer to full load and shut down one of the smaller, natural gas?fired boilers, resulting in annual energy and cost savings of approximately 70,000 MMBtu and $490,000.

In 2007, plant personnel began insulating the tire presses. They finished installing heat blankets on each of the presses at the end of 2007, and the insulation is yielding annual energy savings of approximately 23,000 MMBtu of natural gas and 224,000 gallons of No. 6 fuel oil, with cost savings of $385,000.

The plant intends to implement the recovery of process waste heat during a future scheduled plant shutdown.

Total energy savings from the implementation of the two recommendations is estimated at approximately 93,000 MMBtu of natural gas and 224,000 gallons of No. 6 fuel oil. With total implementation costs of $180,000 and annual energy cost savings of $875,000, these achievements will yield a simple payback of just 2.5 months. The plant’s natural gas costs have declined since the spring of 2006, resulting in lower energy cost savings than originally projected by the assessment. The methodology and results from the assessment were deemed applicable to and are being shared with several other Goodyear facilities.

Lessons Learned

Energy efficiency opportunities in steam systems can deliver significant energy savings without incurring substantial implementation costs. At Goodyear’s Union City tire plant, associates were aware of the potential for energy savings from the measures proposed in the SEN assessment, but before the assessment they had been unsure of the measures’ cost-effectiveness.

The assessment’s calculations of implementation costs and savings revealed that the efficiency opportunities were viable enough to fit the corporate parameters for energy efficiency expenditures. Such opportunities can be replicated in many industrial facilities that use steam.

In addition to the SSAT, other DOE software tools can be used to analyze industrial systems and processes and generate energy efficiency opportunities, including AIRMaster+, the Fan System Assessment Tool (FSAT); MotorMaster+, the Process Heating Assessment and Survey Tool (PHAST); and the Pumping System Assessment Tool (PSAT). These tools can be found at www1.eere.energy.gov/industry/bestpractices/software.html. The North American Insulation Manufacturers Association’s 3E Plus® software can also be useful and is available at www.pipeinsulation.org.

This article has been reprinted with permission from the U.S. Department of Energy (DOE). To learn more about the DOE’s Save Energy Now program, please visit www.eere.energy.gov/industry/saveenergynow.