Advantages: the efficiency of electric dust collector can reach up to about 99%; large gas handling capacity; low flue gas flow rate, low resistance and low operation costs. Shortcomings: complex structure; large size, large area covering; high investments; complex maintenance; special requirements for dust resistance.
This is because, under normal circumstances, the exhaust temperature of the boiler cannot completely condense the water in the flue gas, and the difference between the low calorific value and the high calorific value is mainly in the part of the latent heat of vaporization, so the low heat is used. The value is calculated to reflect the true efficiency of the boiler. However, there will be some special circumstances. For example, if the boiler is a condensing boiler, the calculation of the condensed water portion should be calculated using the high calorific value.
A dryback boiler has a rear wall that is lined with refractory, a wetback boiler has a rear wall that is jacketed by water. Because of this fact, wetback boilers typically boast higher efficiency than dryback boilers as the heat from combustion goes directly into heating water instead of refractory. Wetback boilers are also more forgiving with load changes as the reversal chamber of the boiler is totally submerged in water creating an even heat transfer on the intermediate tube sheet to furnace joint.
