Definition - What does Boiler mean?
A boiler is an enclosed vessel in which a fluid such as water is heated to produce steam or the vaporized form of a liquid. The steam or hot water is then circulated through a piping system, to transfer heat for various applications such as heating, power generation and other processes. Boilers and associated systems are efficient heat exchange systems, however they can be dangerous if not properly maintained and operated.
Corrosion is one of the major contributors of boiler failures and it is important to prevent it, continuously monitor and apply effective control techniques.
Corrosionpedia explains Boiler
A boiler is an energy conversion or transfer system where chemical energy from fuel is converted into either heat or electrical energy. It consists of a tank or a closed vessel in which liquid is stored and heated using hot gases generated from the combustion of fuels such as coal, fuel oil or natural gas that burn in a furnace, or from electrical coils.
There are two main categories of boilers, and each can further be subdivided to several types:
- Fire-tube boiler - Hot gas in several tubes is used to heat the surrounding water.
- Water-tube boiler - Water in the tubes is heated by the surrounding hot gas.
Boilers are widely used in domestic and industrial applications such as:
- Thermal power plants
- Industrial processes
- Sterilizing equipment
Corrosion is one of the major contributors of boiler failures. Factors that influence corrosion in boilers include:
- High oxygen concentration
- High temperatures
- High or low pH levels
- Impurities in the water
- Hydrogen embrittlement
- Acidic corrosion
- Steam side burning (a chemical reaction between the tube metal and steam)
- Fatigue cracking caused by repeated cyclic stress
- Mechanical and operational factors such as:
- Excessive velocities
- Severity of service
- Metal stresses
- Other design and operational issues
Boiler design, operations and maintenance, must conform to international safety standards and regulations to ensure reliability, safety, efficiency and prevent hazards associated with boiler failures such as explosions.
Effective corrosion prevention, monitoring and control are essential for boiler reliability. The control technique is determined by the type of corrosion. Common methods include maintaining proper pH, controlling oxygen, deposits and impurities, and reduction of stress by proper design and operational procedures.