Boiler Blog | Nationwide Boiler Inc.

The price of fuel is constantly fluctuating and with it comes creative ways to be more economical. Finding methods to be more energy efficient is never a waste of time. In the boiler room, efficiency improvements can be found by many sources, however, a common option for energy savings includes the use of an economizer. What is an economizer? The economizer is a fabricated assembly of finned tubing that captures waste heat extracted from the boiler’s stack flue gases; the exhaust that leaves the boiler stack (or “flue”).

It’s all about the principle of Heat Transfer. While low temperature water, or feedwater, enters a boiler system, high temperature flue gas exits. An economizer captures heat from the flue gas that would typically go to waste, and utilizes it to preheat the feedwater. By doing this, an economizer is able to increase thermal efficiency by decreasing the energy required to heat the water to steam. This will typically result in a reduction of 1% in fuel cost per 10 degree rise in feedwater temperature. Overall, an economizer can be a major cost savings for boiler owners and will easily provide a quick return on investment.

The economizers’ simple technology and static parts provide longevity and low maintenance, and they are available in multiple designs and configurations. Conventional economizers are cylindrical or rectangular and come in a range of sizes for both firetube and watertube boilers. Rectangular designs are more commonly used for larger industrial watertube boilers, and can be configured for vertical or horizontal gas flows, finned or bare tube design, and other additional options if needed. A condensing economizer can improve waste heat recovery even further by cooling the flue gas below its dew point, reclaiming both sensible heat from the flue gas and latent heat by condensing the flue gas water vapor.

When determining whether an economizer is ideal for your boiler equipment, the location of the economizer into stack is important. To ensure the most thermal recovery during the process, you need to make sure the economizer is installed as close to the furnace breach as possible. This will help avoid thermal loss and cooling.

At Nationwide Boiler, we offer our EconoStak economizer as an optional addition (or a standard addition in some cases) on our fleet of watertube rental boilers. The EconoStak consists of the economizer as well as all of the associated piping and structural supports required for very efficient and safe operation. In addition, we are a West Coast representative for E-Tech Heat Recovery Systems, a leading provider of economizers for new, replacement, and retrofit applications.

Contact Nationwide Boiler today to see if an economizer is the right option for you, and be sure to check out our previous Boiler Basics 101 blogs. We review various topics each month, so stay tuned for the next edition!

1    Operate Boilers At or Close to Design Capacity. This decreases fuel consumption per unit of production and can result in an estimated energy savings range of 1 percent to 5 percent.  Likewise, if your facility or plant requires excess capacity, visit the Nationwide Boiler website to obtain a current list of boilers for rent or for sale.  Nationwide Boiler provides new and used boilers that can ship immediately, anywhere around the world (conditions apply, contact Nationwide Boiler for details).
2    Reduce Combustion Excess Air. Measure and control air-fuel ratio or oxygen and carbon monoxide content of flue gases from process heating equipment such as furnaces, ovens, and boilers for the entire range of operation. This has an estimated energy savings range of 2 percent to 15 percent. Think about installing a standard low NOx / low excess air burner (compared to an ULN / high excess air burner) on your boiler.  Complemented with a Nationwide CataStak™ Selective Catalytic Reduction System (SCR), a new burner retrofit and SCR installation will not only provide immediate energy savings, but will also reduce NOx emissions and decrease your carbon footprint.
3    Clean Heat Transfer Surfaces. Cleaning heat transfer surfaces lowers flue gas temperature and increases efficiency by improving heat transfer. Doing so can save an estimated 1 percent to 5 percent at a moderate cost.
4    Reduce Radiation Losses from Openings. Reducing radiation losses can save an estimated 1 percent to 2.5 percent at a relatively low cost.
5    Use Proper Oven, Furnace or Boiler Insulation to Reduce Wall Heat Losses. Reducing wall losses produces energy savings of 1 percent to 2 percent with only a moderate investment.
6    Insulate Steam Lines Leaving the Boiler as well as Air- or Water-Cooled Surfaces Exposed to the Oven or Furnace Environment. With an estimated energy savings range of 1 percent to 5 percent, piping insulation can be completed for a moderate investment.
7    Install Air Preheaters or Other Heat Recovery Equipment. This type of equipment recovers available heat from exhaust gases and boiler blowdown and transfers it back into the system by preheating. The potential energy savings range id from 1 percent to 25 percent, depending on process temperatures and other variables.  Consider a Nationwide Boiler EconoStak Economizer or a Heat Recovery (HR) Blowdown Pak to recover valuable heat that can be reused, allowing you to save money in the long-term.

Adapted from Process Heating Magazine, March 21, 2012.

Have you been considering steam system improvements in your plant, but do not know where to begin? Do you want to potentially save 10% or more in fuel costs, while reducing emissions?

The U.S. Department of Energy's (DOE) Industrial Technologies Program can help answer those questions for you and has developed the Steam System Scoping Tool (SSST) for energy coordinators, facility managers and plant electricians to help evaluate your steam system's performance. The software (available in MS Excel or Visual Basic formats) asks 26 questions about different areas of your steam system including system profiling, steam system operating practices, boiler plant operating practices, and distribution and recovery operation practices. Based on your responses, the software will indicate opportunities for improvements and will suggest a range of ways to save steam energy and boost productivity. It also compares your system against similar facilities in your industry and identifies best practices.

According to the DOE, six DOE Industrial Assessment Centers used the SSST in 2001 to assess steam systems at 18 small and medium-sized facilities. Overall, the software identified 89 system improvements with an average fuel savings of 12.5%. Collectively, the total improvements yielded a total annual savings of $2.8 million.

To learn more about this free software, visit the DOE's website.

Call Nationwide Boiler at 800-277-1966 to let us know how much energy you are able to save. We can also provide you with valuable information about our energy efficient equipment for sale or for rent, including EconoStak economizers, Best Performance Standards (BPS) boilers and CataStak SCR systems for boilers and gas-fired turbines.

Nationwide Boiler's sales team will be exhibiting at booth 2578 at the 22nd annual Power-Gen international trade show, December 14-16 at the Orange County Convention Center, Orlando, FL.

To receive a complimentary exhibit floor pass, please contact Nationwide Boiler at info@nationwideboiler.com.