Power Plant - Thumb Rules

• Stack temperature greater than 200 C indicates potential for recovery of waste heat
• Uncontrolled continuous blowdown is very wasteful.
• Add a waste heat recovery system to blowdowns.
• Elevated stack temperature may indicate excessive soot build up or scaling on the water side.
• Stack temperatures should be checked and recorded regularly as an indication of soot deposits.
• Throttling dampers lack accuracy, they may be replaced by variable speed drive.
• 22 C reduction in flue gas temperature increases boiler efficiency by 1%
• 6 C raise in feed water temperature by economiser, condensate recovery system corresponds to 1 % saving in fuel consumption.
• 20 C raise in preheated combustion air temperature by waste heat recovery results in 1 % fuel saving.
• A 1mm thick scale deposit in the water side could increase fuel consumption by 5-8%
• A 3 mm thick soot deposits on the heat transfer surface can cause in fuel consumption to the range of 2-5%
• 0.25mm thick air film offers the same resistance to heat transfer as a 330mm thick copper wall
• 70% heat loss can be reduced by floating a layer of 45mm diameter polypropylene(plastic) balls on surface of 90 C hot liquid.
• 6% increase in GDP would contribute to 9% increase in energy demand.