effect of coal fineness on boiler performance. effect of coal fineness on boiler performance coal drying equipment and impact of fuel moisture on plant performance and . The improvement in boiler and unit performance, achieved during the test by . to pulverize, and less mill power is needed to achieve the same coal fineness.
Coal Quality and Boiler Efficiency • Losses from Boiler • Dry Gas Loss depends on • Exit Gas Temperature • Excess Air • Loss due to Moisture and Hydrogen in coal • Moisture in coal • Every 1% increase in moisture decreases the Boiler Efficiency by 0.1-0.2% • Hydrogen in Coal • Every 1% increase in hydrogen content decreases the boiler efficiency by 1.5-2% • Sensible heat due to ash
The mill outlet temperature of coalair mixture is maintained between 65 to 90 The coal fineness has an effect on the combustion performance like the bottom ash But the main change was in bottom ash combustibles due to increase in 50 .
While all these are regarding the mill performance, the coal fineness and mill out let temperature also affect the boiler performance. The coal fineness has an effect on the combustion performance like the bottom ash percentage combustibles when the plus 50 mesh percentage goes up. It has been very well established that in the case of tangential firing system, the percentage of combustibles has a direct bearing on the plus 50 mesh percentage.
Coal fineness is a relative measurement of particle size distribution typically applied to the product leaving a pulverizer. Standardized wire mesh screens are stacked and used to shake down samples.
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 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 other 50% losses are carbon loss and dry gas loss.
The adverse effects are compounded because burners having more coal will likely be of lower fineness making it even more difficult to achieve complete combustion in the burner belt zone. Importance of Fineness. Poor Coal Fineness often yields poor distribution as large coal particles & air mix to form a (2) phase mixture which will not homogenize.
Effect of moisture in coal on station heat rate and fuel cost of Indian thermal power plants Article (PDF Available) · December 2015 with 5,789 Reads How we measure 'reads'
Effects of Mill Performance on Unburnt Carbon in Coal-fired Boilers. While renewable energy has undergone wide and rapid deployment, coal is still expected to be the main source of fuel for producing base load power in the near future. This is because coal reserves are expected to last for the next century and its cost is still relatively cheap.
A switch to Powder River Basin coal can stress those plants' boiler systems, especially the pulverizers, beyond their design limits and cause no end of operational and maintenance problems.