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During maintenance, insulation over pipes, valves, and fittings is often damaged or removed and not replaced. Uninsulated pipes, valves, and fittings can be safety hazards and sources of heat loss. Removable and reusable insulating pads are available to cover almost any surface. The pads are made of a non-combustible inside cover, insulation material, and a non-combustible outside cover that is tear- and abrasion-resistant. Materials used in the pads are oil- and water-resistant and can be designed for temperatures up to 1600 degrees Fahrenheit. The pads are held in place by wire laced through grommets or by using straps and buckles.

Applications

Reusable insulating pads are commonly used in industrial facilities for flanges, valves, expansion joints, heat exchangers, pumps, turbines, tanks, and other irregular surfaces. The pads are flexible and vibration resistant and can be used with equipment that is horizontally or vertically mounted or difficult to access. Any high-temperature piping or equipment should be insulated to reduce heat loss, reduce emissions, and improve safety. As a rule of thumb, any surface over 120 degrees Fahrenheit should be insulated for protection of personnel. Insulating pads can be easily removed for periodic inspection or maintenance and replaced as needed. Insulating pads can also contain built-in acoustical barriers for noise control.

Availability

Insulation supply companies are located regionally to expedite delivery and to meet site-specific job requirements. Most supply companies can take measurements on-site to ensure the best fit on irregular surfaces.

Source: Office of Industrial Technologies, Energy Efficiency and Renewable Energy, U.S. Department of Energy

Operating your boiler with an optimum amount of excess air will minimize heat loss up the stack and improve combustion efficiency. Combustion efficiency is a measure of how effectively the heat content of a fuel is transferred into a usable heat. The stack temperature and flue gas oxygen (or carbon dioxide) concentrations are primary indicators of combustion efficiency. Given complete mixing, a precise or stoichiometric amount of air is required to completely react with a given quantity of fuel. In practice, combustion conditions are never ideal and additional or “excess” air must be supplied to completely burn the fuel.

Flue Gas Analyzers

The percentage of oxygen in the flue gas can be measured by inexpensive gas absorbing test kits. More expensive ($500 – $1,000) hand-held, computer-based analyzers display percent oxygen, stack gas temperature, and boiler efficiency. They are a recommended investment for any boiler system with annual fuel costs exceeding $50,000.

Oxygen Trim Systems

When fuel composition is highly variable (such as refinery gas, hog fuel, or multi-fuel boilers) or where steam flows are highly variable, an on-line oxygen analyzer should be considered. The oxygen “trim” system provides feedback to the burner controls to automatically minimize excess combustion air and optimize the air-to-fuel ratio.

Source: Office of Industrial Technologies, Energy Efficiency and Renewable Energy, U.S. Department of Energy

All industrial facilities have a network of piping that carries water or other liquids. According to the U.S. Department of Energy Study, 16% of a typical family’s electricity costs are for its pumping systems. The power consumed to overcome the static head in a pumping system varies linearly with the flow and very little can be done to reduce the static component of the system requirement. On the other hand, several energy and money-saving opportunities exist to reduce the power required to overcome the friction component of the pumping system. The frictional power required is dependent on the rate of flow, pipe size (diameter), the overall length of the pipe, pipe characteristics (surface roughness, material, etc.) and properties of the liquid being pumped.

Suggested Actions

• Compute annual and life cycle cost for systems before making an engineering design decision.
• In systems dominated by friction head, always evaluate pumping costs for a couple of different pipe sizes and try to accommodate pipe size with the lowest overall life-cycle cost.
• Look for ways to reduce friction factor. If your application permits, the use of plastic or epoxy-coated steel pipes can reduce friction factor by more than 40%; proportionately reducing your pumping costs.

Source: Office of Industrial Technologies, Energy Efficiency and Renewable Energy, U.S. Department of Energy

Voltage unbalance degrades the performance and shortens the life of a three-phase motor. Voltage imbalance at the motor stator terminals causes phase current unbalance far out of proportion to the voltage unbalance. Unbalanced currents lead to torque pulsations, increased vibrations and mechanical stresses, increased losses, and motor overheating, which results in a shorter winding insulation life. It is recommended that the voltage unbalances at the motor terminals not exceed 1%. Unbalances over 1% require derating of the motor and will void most manufacturers’ warranties. Common causes of voltage unbalance include:

• Faulty operation of power factor correction equipment
• Unbalanced or unstable utility supply
• Unbalanced transformer bank supplying a three-phase load that is too large for the bank
• Unevenly distributed single-phase loads on the same power system
• Unidentified single-phase to ground faults
• An open circuit on the distribution system primary

Suggested Actions

Regularly monitor voltages at the motor terminals to verify that voltage unbalance is maintained below 1%. Check your electrical system single-line diagrams to verify that single-phase loads are uniformly distributed. Install ground fault indicators as required and perform annual thermographic inspections. Another indicator that voltage unbalance may be a problem is 120Hz vibration. A finding of 120 Hz vibration should prompt an immediate check of voltage balance.