In thermal power plants, various types of pumps play crucial roles in the efficient operation of the plant, ensuring the continuous movement of fluids like water, steam, oil, and chemicals within different subsystems. These pumps are essential for power generation, heat transfer, cooling, and maintaining system pressure. Here’s an overview of pumping applications in thermal power plants and their specific roles:
1. Boiler Feedwater Pump (BFP)
- Function: Boiler feedwater pumps are used to supply water to the boiler for steam generation. The pump must overcome the pressure in the boiler to deliver water into the system, making high-pressure feedwater pumps crucial in thermal power plants.
- Operation:
- Pumps water from the feedwater tank (often condensate from the steam turbine) into the boiler.
- The feedwater is often preheated to improve boiler efficiency and reduce thermal stress.
- Key Considerations: These pumps must operate at high pressures (up to several hundred bars in some cases) to inject water into high-pressure boilers.
- Importance: They ensure a continuous supply of water to the boiler, which is essential for maintaining steam pressure and the generation of electricity.
- Type of Pump Used: High-pressure multistage centrifugal pumps.
2. Condensate Extraction Pump (CEP)
- Function: Condensate extraction pumps (CEP) are used to move condensate (condensed steam) from the condenser back to the feedwater system. After the steam passes through the turbine, it condenses in the condenser, and the condensate is pumped back into the system to be reused.
- Operation:
- Extracts condensate from the low-pressure section of the steam condenser and pumps it toward the feedwater heater.
- Helps maintain the water cycle in the power plant by recycling the condensed steam.
- Key Considerations: The pumps handle low-pressure condensate and must be efficient to maintain the plant’s overall efficiency.
- Type of Pump Used: Vertical multistage centrifugal pumps, often installed in a submerged configuration.
3. Cooling Water Pump (CWP)
- Function: Cooling water pumps are responsible for circulating large volumes of water from a cooling source (like a river, lake, or cooling tower) through the condenser to absorb heat from the steam exiting the turbine. This process cools the steam and converts it back into water (condensate).
- Operation:
- These pumps move water to the condenser to cool and condense the exhaust steam from the turbine.
- In some plants, the water is recirculated through cooling towers to be reused.
- Key Considerations: These pumps need to handle large flow rates and are often designed to run continuously at full capacity, making them highly energy-intensive.
- Type of Pump Used: Large axial or mixed-flow pumps for high-volume, low-pressure applications.
4. Circulating Water Pump (CWP)
- Function: Circulating water pumps transport water from cooling towers or other cooling sources to the condenser, facilitating heat dissipation.
- Operation:
- Moves cooling water from a cooling tower or other body of water to the steam condenser and back, in a closed-loop or open-loop system.
- The system must provide enough flow to maintain cooling efficiency.
- Type of Pump Used: Large axial flow or mixed flow pumps.
5. Condensate Transfer Pump
- Function: This pump is used to transfer condensate collected from the condenser to the feedwater system or a storage tank.
- Operation:
- Moves the condensed steam from the condenser to the feedwater storage tanks for reuse in the boiler.
- Type of Pump Used: Horizontal centrifugal pumps are typically used for this application.
6. Boiler Circulation Pump
- Function: Boiler Circulation Pump water within the boiler drum and water tubes to maintain uniform water circulation. This ensures that the water is heated evenly, preventing localized overheating and enhancing steam generation efficiency.
- Operation:
- Circulates water between the boiler drum and water tubes.
- Essential for forced circulation boilers where water needs to be mechanically circulated.
- Type of Pump Used: Centrifugal pumps or high-temperature circulating pumps capable of handling high pressures and temperatures.
7. Fuel Oil Pump
- Function: Fuel oil pumps are used in thermal power plants that use fuel oil as part of the combustion process. These pumps move fuel oil from storage tanks to the burners, where the oil is atomized and combusted to generate heat for steam production.
- Operation:
- Transfers fuel oil to the burners at the appropriate pressure for efficient combustion.
- Type of Pump Used: Positive displacement gear or screw pumps for handling viscous fuels like heavy fuel oil.
8. Lubricating Oil Pump
- Function: Lubricating oil pumps are critical for providing a continuous supply of oil to lubricate the bearings and moving parts of turbines, generators, and other rotating machinery in the plant.
- Operation:
- Delivers oil to the bearings and other components to reduce friction and wear.
- Operates continuously to ensure that machinery is properly lubricated.
- Type of Pump Used: Positive displacement pumps such as gear pumps.
9. Ash Handling System Pumps
- Function: Pumps in the ash handling system are used to transport fly ash and bottom ash produced by coal combustion. Fly ash is collected from the flue gases, and bottom ash is removed from the bottom of the furnace.
- Operation:
- Pumps transport ash slurry to disposal areas or to silos for storage.
- Handles abrasive materials and often involves slurry pumping.
- Type of Pump Used: Slurry pumps designed to handle abrasive, high-density ash slurry.
10. Fire Water Pump
- Function: Fire water pumps are critical for fire protection in power plants. These pumps are connected to the plant’s firefighting system and provide high-pressure water to sprinkler systems, hydrants, and fire hoses in case of a fire emergency.
- Operation:
- Delivers water at high pressure to suppress fires in critical areas.
- Type of Pump Used: Centrifugal or vertical turbine pumps, often diesel-powered for backup reliability.
11. Makeup Water Pump
- Function: Makeup water pumps are used to add fresh water into the system to compensate for water losses due to steam evaporation, blowdown, or leaks in the system.
- Operation:
- These pumps draw water from external sources (rivers, lakes, or desalination plants) and add it to the condensate/feedwater system to maintain water levels.
- Type of Pump Used: Horizontal centrifugal pumps are typically used for makeup water applications.
12. Seal Water Pump
- Function: Seal water pumps provide water to cool and lubricate mechanical seals in various pumps, particularly those handling high-temperature fluids or steam. Seal water helps to maintain the integrity of the seals and prevent leakage.
- Operation:
- Circulates cooling water around mechanical seals to prevent overheating and seal failure.
- Type of Pump Used: Centrifugal pumps, usually low-flow, high-head pumps.
13. Desalination or Demineralization Pump
- Function: In thermal power plants where freshwater is scarce, desalination pumps are used to supply demineralized or desalinated water to the feedwater system. This is essential for preventing scaling and corrosion in boilers and turbines.
- Operation:
- Pumps water through desalination systems (like reverse osmosis) to produce high-quality water for use in the boiler system.
- Type of Pump Used: High-pressure pumps capable of handling the pressures needed for desalination.
14. Soot Blower Pump
- Function: Soot blower pumps are used to inject water or steam to remove soot and ash deposits from the boiler tubes, enhancing heat transfer and improving boiler efficiency.
- Operation:
- Pumps steam or water to clean the boiler tubes and prevent soot accumulation.
- Type of Pump Used: High-pressure pumps, often designed to handle steam injection.
15. Air Preheater Pump
- Function: Air preheater pumps are used to circulate air or fluid in systems designed to recover heat from the exhaust gases, preheating the combustion air to increase efficiency.
- Operation:
- Circulates air or water to the air preheater system, improving thermal efficiency.
- Type of Pump Used: Centrifugal pumps for air circulation or water preheating systems.
16. Wastewater Treatment Pumps
- Function: In thermal power plants, wastewater treatment pumps are used to treat and move wastewater from different areas, including boiler blowdown and cooling tower discharges, to water treatment plants for purification or discharge.
- Operation:
- Pumps wastewater from various parts of the plant to treatment facilities for cleaning and reuse or discharge.
- Type of Pump Used: Submersible or centrifugal pumps.