How To Improve Boiler Efficiency

ZBG is a preeminent industrial boiler and pressure vessel manufacturer and supplier in China, offering global clients with best products and service. To improve boiler efficiency is to save money. There are 13 points to pay attention and improve your boiler efficiency. 1. Stack temperature control 2. Feed water preheating using economizers 3. Combustion air pre-heating 4. Incomplete combustion minimization 5. Excess air control 6. Avoid radiation and convection heat loss 7. Automatic blow down control 8. Reduction of scaling and soot losses 9. Reduction of boiler steam pressure 10. Variable speed control 11. Controlling boiler loading 12. Proper boiler scheduling 13. Boiler replacement

1. Stack Temperature Control
• Keep as low as possible• If >200°C then recover waste heat
2.Feed Water Preheating Economizers
• Potential to recover heat from 200 – 300 oC flue gases leaving a modern 3-pass shell boiler
3.Combustion Air Preheating
• If combustion air raised by 20°C = 1% improve thermal efficiency
4.Minimize Incomplete Combustion
• Smoke, high CO levels in exit flue gas
5.Excess Air Control
• Excess air required for complete combustion• Optimum excess air levels varies• 1% excess air reduction = 0.6% efficiency rise• Portable or continuous oxygen analyzers
6.Radiation and Convection Heat Loss Minimization
• Fixed heat loss from boiler shell, regardless of boiler output• Repairing insulation can reduce loss
7.Automatic Blow Down Control
• Sense and respond to boiler water conductivity and pH
8.Scaling and Soot Loss Reduction
• Every 22oC increase in stack temperature = 1% efficiency loss• 3 mm of soot = 2.5% fuel increase
9.Reduced Boiler Steam Pressure
• Lower steam pressure = lower saturated steam temperature = lower flue gas temperature• Steam generation pressure dictated by process
10.Variable Speed Control for Fans, Blowers and Pumps
• Suited for fans, blowers, pumps• Should be considered if boiler loads are variable
11.Control Boiler Loading
• Maximum boiler efficiency: 65-85% of rated load• Significant efficiency loss: < 25% of rated load 51
12.Proper Boiler Scheduling
• Optimum efficiency: 65-85% of full load• Few boilers at high loads is more efficient than large number at low loads
13.Boiler Replacement Financially attractive if existing boiler is
• Old and inefficient• Not capable of firing cheaper substitution fuel• Over or under-sized for present requirements• Not designed for ideal loading conditions