Introduction:
Drum boiler heat exchangers are a unit which is rated at a certain temperature and pressure to force the boiler feed water into the vapour phase (steam). As the vapour phase is formed the liquid level in the drum decreases. It is important to maintain control of the liquid level in the boiler drum to prevent damage to the unit. Complex control schemes have been developed control the level of the drum by adjusting the rate of flow, the inlet temperature etc. The steam formed in the boiler drum still contains a certain percent of liquid content. This liquid contained in the steam is referred to as the quality. The two phase system that is formed (liquid & vapour) in the boiler drum heat exchanger is then cycled though the boiler several times before it is sent to the super heater unit.
Process Of Drum Boiler Heat Exchangers:
Principles of drum boiler heat exchangers Fire tube boilers are generally used for relatively small steam capacities and low to medium steam pressures. These boilers are compact, of packaged construction and cheaper. Water tube boiler is a kind of boiler where the water is heated inside tubes and the hot gasses surround them. This is just opposite of fire tube boiler. In this boiler, boiler feed water flows through the tubes and enters the boiler drum. The circulated water is heated by the combustion gases and converted into steam at the vapour space in the drum. This boiler is used when the steam demand as well as steam pressure requirements are high as in the case of boiler needed to meet the steam requirements for industrial processes as well as for power generation .
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Materials Of Drum Boiler Heat Exchangers:
- Wall thickness up to 300 mm (12 inches)
- Drum internals such as cyclone and separators, driers fabrication facility available
- Materials include: ◦Manganese- Silicon Carbon steel (SA 299)
- Molybdenum Alloy Steel (SA302 Gr. B & SA 533)
- Carbon Steel.
Applications Of Drum Boiler Heat Exchangers:
In applications of tube enhancement is the objective may be to recover or reject heat, or sterilize, pasteurize, fractionate, distil, concentrate, crystallize, or control a process fluid. Heat exchanger for an ocean thermal energy conversion (OTEC), Heat exchangers for process industries, Sugar factories, diary plants, Chemical industries Heating and cooling in evaporators, Heat exchangers thermal power plants, air- conditioning equipment, refrigerators, radiators for space vehicles, automobiles.