In a fire tube boiler, the flue gas generated after the combustion of the fuel flows through the fire tube or the smoke tube, and heats the water, steam or steam-water mixture outside the fire tube or the smoke tube. Fire tube boilers, also known as shell boilers, are less efficient due to the limitations of their structural conditions. They are generally used for users with small capacity.
1. The capacity and pressure of the fire tube boiler are greatly limited. Generally, the evaporation amount does not exceed 30 t/h, and the pressure does not exceed 2 MPa.
2. The fire tube boiler has a simple structure, low construction cost, and easy operation.
3. Low failure, easy maintenance and low maintenance costs.
4. The water storage and storage capacity are large, and the load is more flexible when the load changes.
5. The boiler has a small footprint, is easy to install, move and overhaul, has a large water volume, and has low fluctuations in pressure and water level after starting.
6. Tthe boiler has low water quality requirements and the smoke resistance is small.
1. Since all or most of the heated surface of the fire tube boiler is placed in the drum, to increase the boiler capacity and increase the pressure, the diameter and wall thickness of the drum must be increased, and the amount of metal used is greatly increased.
2. Due to the limitation of the drum, the boiler has a small heating area, so the exhaust temperature is high and the boiler is inefficient.
3. The amount of water stored is large, and the damage is large in case of rupture.
4. Easy to block ash during operation
5. The heat transfer effect is not good