Three-drum boilers are a class of water-tube boiler used to generate steam, typically to power ships. They are compact and of high evaporative power, factors that encourage this use. Other boiler designs may be more efficient, although bulkier, and so the three-drum pattern was rare as a land-based stationary boiler.
Water quality is of the utmost importance in proper and safe boiler operations. An improperly treated feedwater system can result in the scaling of the boiler internals, safety equipment and auxiliary piping.
The construction and working principle of the boiler economizer is simple. At the bottom part, it has a horizontal inlet pipe through which we feed water with normal temperature to the economizer. There is another horizontal pipe fitted at the top of the economizer.
To prevent scale formation from low remaining levels of hardness which may have escaped treatment. Sodium phosphate is normally used for this, and causes the hardness to precipitate to the bottom of the boiler where it can be blown down.
1) The entire plant may be purchased as a complete package, only needing securing to basic foundations, and connecting to water, electricity, fuel and steam systems before commissioning. This means that installation costs are minimised.
2) This package arrangement also means that it is simple to relocate a packaged shell boiler.
3) A shell boiler contains a substantial amount of water at saturation temperature, and hence has a substantial amount of stored energy which can be called upon to cope with short term, rapidly applied loads.
*This can also be a disadvantage in that when the energy in the stored water is used, it may take some time before the reserve is built up again.
4)The construction of a shell boiler is generally straight forward, which means that maintenance is simple.
5)Shell boilers often have one furnace tube and burner. This means that control systems are fairly simple.
Although shell boilers may be designed and built to operate up to 27 bar, the majority operat
If the impurities in the boiler feedwater are not dealt with properly, carryover of boiler water into the steam system can occur. This may lead to problems elsewhere in the steam system, such as:
According to the power of water or steam circulation, boilers can be divided into natural circulation boilers, forced circulation boilers, once-through boilers and combined circulation boilers.
