Large U.S. plants can save millions of dollars in energy and maintenance costs each year by improving the energy efficiency of their steam or process heating systems. This was one of the major findings of U.S. Department of Energy (DOE) Energy Experts and plant assessment teams when they evaluated the energy efficiency of industrial steam or process heating systems in 200 large, energy-intensive U.S. plants in 2006.

In the Winter 2007 issue of Energy Matters, we described the top 10 energy-saving recommendations in terms of how frequently they were made in all the plant energy assessments conducted in 2006. Since then, energy-efficiency specialists in the DOE Industrial Technologies Program (ITP) and at Oak Ridge National Laboratory have analyzed how much energy and money those plants could save by following the recommendations in their Save Energy Now energy assessments. They also looked at potential emission reductions and other benefits. The full report on the 2006 assessments is available on the Results page of the Save Energy Now Web site.

Tables 1 and 2, which are based on the report's findings, list the top five money-saving recommendations among all those made for industrial process heating systems and the top five for steam systems, out of about 30 recommendations made for each type of system. The tables also include the potential natural gas savings and estimated environmental emissions reductions associated with each recommendation.

Following each table are links to ITP resources, such as tip sheets, produced by technical experts in energy-efficient industrial systems. These resources, and those listed at the end of the article, can help you start to Save Energy Now in your own plant.

Five Ways to Reduce Process Heating Energy and Maintenance Costs

Table 1 shows the top five potential money-saving recommendations made in the 2006 Save Energy Now energy assessments that focused on improving process heating systems.

Table 1. Top Five Money-Saving Recommendations for Process Heating

Recommendation from 2006 Save Energy Now Process Heating Assessments

Total Potential Cost Savings
(per yr)*

Total Potential Natural Gas Savings
(MMBtu/yr)*

Total Potential Reductions in Carbon Dioxide
(metric tons)*

Recover and use heat from industrial furnaces

$20 million

1 million

182,000

Use heat cascading

$16 million

2 million

142,000

Use proper heating methods

$13 million

1 million

74,000

Use proper furnace insulation and maintenance techniques

$12 million

1 million

124,000

Reduce flue gas oxygen content

$9 million

878,000

111,000

*Rounded to the nearest thousand or million.

Details and Resources for Process Heating

Some of the following documents are available as Adobe Acrobat PDFs. Download Adobe Reader.

1. Recover and use heat from industrial furnaces:

To make use of the considerable heat from industrial furnaces, see these tips:

  • Install Waste Heat Recovery Systems for Fuel-Fired Furnaces (PDF 281 KB)
  • Load Preheating Using Flue Gases from a Fuel-Fired Heating System (PDF 266 KB)

2. Use heat cascading:

The heat from flue or exhaust gases in higher temperature processes can be used to supply heat to lower temperature processes, as described in this tip:

  • Using Waste Heat for External Processes (PDF 290 KB)

3. Use proper heating methods:

To increase your process heating savings by replacing inefficient, uneconomical methods with efficient, economical systems, see these tips:

4. Use proper furnace insulation and maintenance techniques:

To avoid localized losses in furnaces, consider these tips:

5. Reduce flue gas oxygen content:

To lower the oxygen levels in exhaust gases in order to raise available heat levels and improve energy efficiency, see this tip:

Five Ways to Reduce Steam System Energy and Maintenance Costs

Table 2 shows the top five potential money-saving recommendations made in 2006 during Save Energy Now energy assessments that evaluated industrial steam systems.

Table 2. Top Five Money-Saving Recommendations for Steam Systems

Recommendation from 2006 Save Energy Now Steam System Assessments

Total Potential Cost Savings
(per yr)*

Total Potential Natural Gas Savings
(MMBtu/yr)*

Total Potential Reductions in Carbon Dioxide
(metric tons)*

Reduce steam demand

$89 million

8 million

1 million

Use alternate fuel

$78 million

14 million

376,000

Improve boiler efficiency

$43 million

4 million

284,000

Add or modify backpressure steam turbine

$34 million

130,000

166,000

Improve condensate recovery

$24 million

2 million

151,000

*Rounded to the nearest thousand or million.

Details and Resources for Steam Systems

Some of the following documents are available as Adobe Acrobat PDFs. Download Adobe Reader.

1. Reduce steam demand:

For information about opportunities for improving the energy use and performance of steam systems as well as the benefits of a systems approach, see this resource from ITP:

  • Improving Steam System Performance: A Sourcebook for Industry (PDF 1.26 MB)

2. Use alternate fuel:

To switch to a fuel with a higher theoretical combustion efficiency and save money on fuel, see these tips:

  • Benchmark the Fuel Cost of Steam Generation (PDF 212 KB)
  • Upgrade Boilers with Energy-Efficient Burners (PDF 212 KB)

3. Improve boiler efficiency:

To reduce boiler losses and use less fuel to achieve the production rate you need, review these tips:

  • Improve Your Boiler's Combustion Efficiency (PDF 238 KB)
  • Install an Automatic Blowdown Control System (PDF 212 KB)
  • Insulate Steam Distribution and Condensate Return Lines (PDF 162 KB)
  • Minimize Boiler Blowdown (PDF 215 KB)
  • Upgrade Boilers with Energy-Efficient Burners (PDF 212 KB)

4. Add or modify a backpressure steam turbine:

To increase your total steam usage and potentially reduce your overall energy costs, see these tips:

  • Consider Installing High-Pressure Boilers with Backpressure Turbine-Generators (PDF 266 KB)
  • Replace Pressure-Reducing Valves with Backpressure Turbogenerators (PDF 240 KB)

5. Improve condensate recovery:

To increase the condensate returned to the boiler and supply hotter water to the boiler feedwater system, try this tip:

Additional Resources

To review the entire report on the 2006 plant assessments, Results from the U.S. DOE 2006 Save Energy Now Assessment Initiative, you can visit the ITP Save Energy Now Web site or order the CD. And for more information about how to improve your plant's process heating or steam system efficiency, see the following ITP resources.

To improve process heating system efficiency:

To improve steam system efficiency:

And for more information about Save Energy Now energy assessments, including activities planned in 2007, visit the Save Energy Now Web site.

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