A boiler feed pump (BFP) in a thermal power plant pumps feedwater from the deaerator to the boiler at a high pressure, sufficient for steam generation at the desired operating conditions.
Here's a more detailed explanation of how it works:
Boiler Feed Pump Function and Operation
The boiler feed pump is a crucial component in a thermal power plant's water-steam cycle. Its primary function is to provide a continuous and reliable supply of feedwater to the boiler, enabling the generation of steam for power production.
1. Receiving Feedwater:
- The BFP receives feedwater from the deaerator. The deaerator removes dissolved gases, such as oxygen and carbon dioxide, from the water to prevent corrosion within the boiler system.
2. Increasing Pressure:
- The BFP is a high-pressure pump, typically a multistage centrifugal pump. It uses impellers rotating within a casing to add energy to the feedwater, significantly increasing its pressure. The number of stages (impellers) determines the final pressure that the pump can achieve.
3. Delivering to the Boiler:
- The high-pressure feedwater is then delivered to the boiler. The pressure must be high enough to overcome the boiler's internal pressure, which is determined by the desired steam output and operating conditions.
4. Controlling Flow:
- The BFP's flow rate is carefully controlled to match the boiler's steam demand. Control systems monitor the boiler water level and steam pressure, adjusting the pump's speed or using control valves to regulate the feedwater flow.
5. Importance of Reliability:
- The BFP's reliability is paramount. A failure of the BFP can lead to a shutdown of the entire power plant. Therefore, BFPs are designed for high reliability and are often equipped with redundant systems and monitoring equipment.
Key Components and Considerations
- Impellers: These rotating components impart kinetic energy to the feedwater, increasing its pressure.
- Casing: The casing houses the impellers and directs the flow of feedwater through the pump.
- Seals: Seals prevent leakage of high-pressure feedwater from the pump.
- Bearings: Bearings support the pump's rotating components and reduce friction.
- Lubrication System: A lubrication system provides oil to the bearings to minimize wear and ensure smooth operation.
- Driver: The BFP is driven by an electric motor or a steam turbine.
Summary
The boiler feed pump takes feedwater from the deaerator and increases its pressure to a level suitable for injection into the boiler, where it is converted to steam. This crucial function enables the steam generation process in a thermal power plant. The pump's performance and reliability are vital for the efficient and safe operation of the plant.
