Feedwater preheating in a boiler system

Feedwater preheating is an important step in a boiler system as it helps to improve the efficiency of the overall process. The purpose of preheating the feedwater is to raise its temperature before it enters the boiler, which reduces the energy required to convert the water into steam.

Options for preheating feedwater

There are several devices that can be used to preheat the feedwater before it is supplied to the boiler. Out of the given options, the correct answer is economizer.

1. Steam trap: A steam trap is used to remove condensate and non-condensable gases from the steam system. It is not specifically designed for feedwater preheating.

2. Economizer: An economizer is a heat exchanger that recovers heat from the flue gas before it is released into the atmosphere. The recovered heat is used to preheat the feedwater, thus reducing the amount of fuel required to raise its temperature. The economizer is typically located between the boiler and the chimney.

3. Superheater: A superheater is a device that increases the temperature of steam above its saturation point. It is not directly involved in the preheating of feedwater.

Importance of feedwater preheating

Preheating the feedwater before it enters the boiler has several benefits:

1. Improved efficiency: By preheating the feedwater, less fuel is required to raise its temperature to the desired level. This reduces fuel consumption and improves the overall efficiency of the boiler system.

2. Reduced energy costs: With a lower fuel requirement, the cost of energy used in the boiler system is reduced. This can lead to significant cost savings, especially in large-scale industrial applications.

3. Prevention of thermal shock: Preheating the feedwater helps to prevent thermal shock to the boiler. When cold water is introduced directly into a hot boiler, it can cause rapid temperature changes that can damage the boiler and reduce its lifespan.

Conclusion

In summary, the device used to preheat the feedwater before being supplied to the boiler is an economizer. This heat exchanger recovers heat from the flue gas and transfers it to the feedwater, improving the efficiency of the boiler system and reducing energy costs.