Boiler efficiency is mainly depended on the amount of losses in the system. in high capacity pulverized coal fired boilers the total losses account to In high capacity pulverized coal fired boilers the total losses account to about 12 to 14%. Roughly 50% of the losses are governed by fuel properties like hydrogen in fuel, moisture in fuel and ambient air conditions. The best efficiency in the boiler can be achieved if the losses are kept to the minimum. Since 50% of the losses are dependent on the fuel and ambient condition, the best efficiency can be achieved by properly tuning the other 50%, i.e. mainly carbon loss and dry gas loss.
Boiler Efficiency of Coal Fired Boilers
To improve the boiler efficiency of coal-fired boiler, the coal boiler thermal efficiency is the percentage of effective heat of fuel, generally the thermal efficiency of coal-fired boiler is 70-85%. Ways to improve boiler thermal efficiency.
- Reduce the air leakage rate of air preheater, especially the air leakage rate of rotary air preheater.
- Strict control of boiler water quality indicators, when the water-cooled wall tube scaling amount reaches 400mg/m3, should be timely acid cleaning.
- As far as possible, the use of low-sulfur high-quality coal, reduce the air temperature at the inlet of the air preheater.
Coal Fired Boilers Boiler Efficiency
Thermal efficiency of coal-fired boilers can be improved by these two methods.
(1) Adjust the combustion conditions according to the boiler load and combustion time, reasonable air distribution, minimize the center of the furnace flame, so that the coal is fully combusted in the furnace.
(2) Adjusting the raw coal dosage according to the volatile fraction and volatile time of raw coal to keep the best value.
Take 1 ton boiler as an example for boiler thermal efficiency calculation, the boiler produces 600,000 calories of heat per hour and the natural gas calorific value is 8600 calories.
- 600,000 calories/hour 8600 calories/standard cubic meter 100% ~ 69.76 standard cubic meters, i.e. 69.76 standard cubic meters of natural gas can produce 600,000 calories/hour by burning at 100% thermal efficiency, which can meet the operation needs of 1 ton boiler.
- 600,000 calories/hour 8,600 calories/standard cubic meter 92%*75.83 standard cubic meters, i.e. burning 75.83 standard cubic meters of natural gas can produce 600,000 calories/hour, which can meet the operation requirements of a 1-ton boiler.
- 600,000 calories/hour 8600 calories/standard cubic meter 96%*72.67 standard cubic meters, i.e. burning 72.67 standard cubic meters of natural gas can produce 600,000 calories per hour, which can meet the operating requirements of a 1-ton boiler.
