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Nationwide Boiler news and events, industry updates, technical resources and more. You hear it first on The Nationwide Boiler Blog!

Combustion Air Fan & Efficiency

In order for your boiler to operate at peak efficiency, it is important that the correct balance of fuel and combustion air is achieved. Air and fuel ratios are controlled through linkages, fans, dampers and the increase or decrease of gas pressure. Gas pressure is controlled through a pressure regulator and a fan controls the volume of combustion air.
If there are any problems with the fan, more energy may be introduced into the system, causing decreased efficiency. To help ensure that your equipment is running at its peak performance, please review the common fan problems below.

Fan Capacity/Pressure is Below Rating:

  1. Dampers or variable inlet vanes are not adjusted properly

  2. Fan inlet or outlet conditions are impaired

  3. Multiple air leaks within the system

  4. Damage sustained to the blower wheel

  5. Direction of rotation is incorrect

Fan Vibration:

  1. Worn bearings

  2. Unstable foundation

  3. Foreign material in the fan causing an imbalance

  4. Misalignment of bearings, couplings, wheel or v-belt drive

  5. Damaged wheel or motor

  6. Bent shaft

  7. Worn coupling

  8. Loose dampers or variable inlet vanes

  9. Speed too high or incorrect fan rotation

  10. Vibration to fan transmitted from another source

  11. Uneven blade wear

  12. Loose or broken bolts or set screws

Overheated Bearings:


  1. Improper lubrication

  2. Poor alignment

  3. Damaged wheel or driver

  4. Bent shaft

  5. Abnormal end thrust

  6. Dirt in bearings

  7. Improper belt tension

Overload on Driver:

  1. Speed too high

  2. Direction of rotation is incorrect

  3. Bent shaft

  4. Poor alignment

  5. Improper lubrication

  6. Wheel wedging or binding on fan housing
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Minimizing Boiler Blowdown and Decreasing Costs

Even with the best pretreatment programs, boiler feedwater often contains some degree of impurities, such as suspended and dissolved solids. The impurities can remain and accumulate inside the boiler as the boiler operation continue, leading to carryover of boiler water into the steam, causing damage to piping, steam traps and even process equipment. The increasing concentration of suspended solids can form sludge, which impairs boiler efficiency and heat transfer capability.

One way to improve efficiency is to review your blowdown practices. This includes the use of an automatic blowdown control system by regulating water volume discharged in relation to the amount of dissolved solids present.  This system maintains proper water chemistry within acceptable limits, while minimizing blowdown and reducing energy losses. Cost savings come from the significant reduction in the consumption, disposal, treatment, and heating of water.

The U.S. Department of Energy's Industrial Technologies Program calculated annual cost savings associated with the installation of an automatic blowdown control system that reduced blowdown rate from 8% to 6%. The example below assumes a continuously operating natural gas-fired, 150 psig, and 100,000 lb/hr steam boiler. Makeup water temperature of 60 degrees, with boiler efficiency of 83%, with fuel valued at $3.00 MMBTU was used, and the total water, sewage and treatment costs are $0.004 per gallon.

The annual cost savings in the example above equals:

Boiler Feedwater:

Initial = 100,000 / (1-0.08) = 108,695 lbs/hr

Final = 100,000 / (1-0.060 = 106,383 lbs/hr

Makeup Water Savings = Initial - Final, or 108,695 lbs/hr - 106,383 lbs/hr = 2,312 lbs/hr

Enthalpy of boiler water = 338.5 Btu/lb; for makeup water at 60 degrees = 28 Btu/lb

Thermal Energy Savings = 338.5 - 28= 310.0 Btu/lb

Annual Fuel Savings = 2,312 lbs/hr x 8760 hrs/yr x 310.5 Btu/lb x $3.00/MMBtu / 0.82 x 106 = $23,007

Annual Water and Chemical Savings = 2,312 lbs/hr x 8760 hrs/yr x $0.004/gal / 8.34 lbs/gal = $9,714

Annual Cost Savings = $23,007 + $9,714 = $32,721
If you need additional information about feedwater systems or other ways you can decrease costs, contact Nationwide Boiler today and we are happy to discuss ways to improve your bottom line: 1-800-227-1966.

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Improving Boiler Efficiency

It is important for a boiler to run at its most efficient level in order to avoid costly issues and obtain the best results. Excess air is essential in boiler operation to minimize heat loss and improve combustion efficiency.  Here are some tips to help you make sure your boiler is running at the most efficient level possible:

  1. Periodically monitor flue gas composition and tune your boilers to maintain excess air at optimum levels.

  2. If there is a continuous blowdown system in place, consider installing a heat recovery system.

  3. If there is a non-continuous blowdown system, then consider converting it to a continuous blowdown system coupled with heat recovery.

  4. Reduce operating costs through maximizing the return of hot condensate to the boiler.

  5. If a condensate return system is absent, estimate the cost of a condensate return and treatment system (as necessary) and install one if economically justified.

  6. Repair steam distribution and condensate return system leaks.

  7. Insulate condensate return system piping to conserve heat and protect personnel against burns.

  8. Review your blowdown practices to identify energy saving opportunities.

  9. Examine operating practices for boiler feedwater and blowdown rates developed by the American Society of Mechanical Engineers (ASME). Considerations include operating pressure, steam purity, and deposition control.

  10. Consider an automatic blowdown control system.

Taken from http://www.process-heating.com/Articles/Feature_Article/2afcce64fe4fd010VgnVCM100000f932a8c0____
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See The DataStak Demo at Power-Gen!

Nationwide Boiler's newest innovative product - the DataStak Emissions and Efficiency Monitoring System - was highlighted in the latest issue of Today's Boiler Magazine. See the article here: goo.gl/3n2W4v

The DataStak provides boiler operators with information related to the emissions output and efficiency of their boiler systems. In today's marketplace, this data is not just something that most energy and facility engineers want to know, but many need to know this information for reporting purposes.

We designed the DataStak system to provide real-time, unified data at your fingertips, from one convenient, on-site source. It is more than just a combustion or NOx analyzer. The DataStak is a cost effective, packaged emissions and efficiency monitoring system with O2, NOx, CO, and CO2 measurements, in addition to real time boiler efficiency, fuel usage and carbon footprint calculations.

Representatives from Natiownide Boiler are in Las Vegas, NV this week for Power-Gen, the largest power generation event of the year. Experience the power of the DataStak, live and in-person at the show! Visit us at booth #6019 to learn how the DataStak can help you stay informed on how your boiler is performing.

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