Gulf Engineering Helps You Achieve Your Energy Efficiency Goals
When considering the maintenance of boilers and cooling towers it is important to remember that these are carefully designed heat transfer devices. They are doing their jobs only when they are efficiently removing heat from where we don’t want it or putting it where we do want it. Anything that interferes with the desired transfer process results in wasted energy. Scales and deposits on the heat transfer surfaces are thermal insulators and therefore require higher temperatures (or lower temperatures for cooling equipment) or longer contact times to achieve the desired results. With today’s rising energy costs, this greatly impacts your costs for your plant, buildings or facility.
It is generally not appreciated how much of a reduction in the heat transfer efficiency results from fairly thin layers of scale and deposits. The energy losses are highly dependant on the composition of the scales and their specific insulating properties, but some examples are possible. The U.S. Department of Energy reports that just 1/16 inch of scale can reduce fuel use efficiency by over 6%1. Even worse, 1/100 inch of a silica scale will reduce the heat transfer coefficient by 80-90%.2
These solids also result in stressing your system in other ways since more extreme conditions are needed to overcome the insulating properties of scales and deposits. Scales lead to overheating which in turn leads to tube failures.
Operational defects that lead to excessive water use also wastes energy and treatment products. Excessive blowdown requires more make up water and this must all be heated, treated and moved around before it is then discharged prematurely. This is why it is so important to have the proper treatment program and regular maintenance to ensure controllers and feed systems are performing as intended. The right treatment and service costs less.
- U.S. Department of Energy Steam Tip Sheet #7, January 2006.
- James W. McCoy The Chemical Treatment of Cooling Water Chemical Publishing Co.; New York, 1983, p 126.