Application of Submersible Pumps in Power Plants

Submersible pumps are critical auxiliary equipment in power plants. Due to their unique design where the pump body operates submerged in liquid, they offer irreplaceable advantages in handling liquids in various sumps and tanks within the power plant.

I. Core Advantages: Why do Power Plants Choose Submersible Pumps?

Leak-free: The pump shaft is entirely submerged, eliminating the need for dynamic shaft seals and fundamentally resolving seal leakage issues, which is crucial for power plants with stringent environmental requirements.

No Priming Required: Ready to operate immediately upon startup, making them ideal for emergency drainage or automated control drainage systems.

Compact Structure, Small Footprint: The motor is located above, and the pump body is submerged below, requiring no separate pump house. They are particularly suited for installation in confined spaces like sumps and pits.

Good Clog Resistance: Typically equipped with open or closed impellers that have wide flow passages, enabling them to handle wastewater containing certain solid particles (such as sediment, cinder, and debris).

II. Main Application Scenarios

Submersible pumps are used throughout various processes in power plants, primarily tasked with drainage, transfer, and emergency functions.

1. Main Powerhouse Area

Application Scenario: Drainage of turbine hall sumps: Removing coolant leakage from equipment, floor wash water, etc.

Medium Characteristics: Wastewater potentially containing oil contamination and dust.

Pump Requirements: Standard cast iron construction with some clog-handling capability.

2. Boiler Area

Application Scenario: Drainage of bottom pits in the boiler house: Removing wastewater generated from boiler flushing, slag removal, etc.

Medium Characteristics: High water temperature, potentially containing ash and slag particles, can be corrosive.

Pump Requirements: Resistance to high temperature, abrasion, and corrosion; typically stainless steel construction.

3. Water Treatment System

Application Scenario: Drainage of neutralization tanks, wastewater tanks: Transferring wastewater after acid-base neutralization or pre-treated industrial wastewater.

Medium Characteristics: Corrosive (wide pH variations).

Pump Requirements: Wetted parts must be corrosion-resistant materials like stainless steel 304, 316L, or plastics (PP/PVDF).

4. Ash and Slag Handling System

Application Scenario: Drainage of ash slurry tanks, settling ponds: Transferring slurries containing fine ash and slag particles after ash flushing and slag handling.

Medium Characteristics: High concentration, highly abrasive, may contain corrosive ions like Cl-.

Pump Requirements: Heavy-duty slurry pump design with extreme abrasion and corrosion resistance; materials may include high-chrome cast iron or rubber lining.

5. Circulating Water System & Make-up Water System

Application Scenario: Drainage of storage tanks, drainage pits: Removing spillage, leakage, and backwash water from the systems.

Medium Characteristics: Relatively clean but may contain sediment and aquatic organisms.

Pump Requirements: Standard materials with clog-resistant capability.

6. Emergency Systems

Application Scenario: Emergency oil containment sumps, firefighting drainage pits: Emergency removal of hazardous liquids during incidents (like oil leaks, fires).

Medium Characteristics: Could be oil-water mixtures or firefighting wastewater.

Pump Requirements: High reliability, often requiring explosion-proof motors and ability to handle the relevant media.

III. Key Selection Points and Special Requirements

Material Selection: Choose appropriate materials based on medium corrosiveness, abrasiveness, and temperature. Common options include cast iron, stainless steel 304/316L, duplex stainless steel, high-chrome cast iron, and non-metallic materials (PP/PVDF).

Temperature Resistance: High-temperature environments like the boiler area require pumps designed for high temperatures (e.g., motors with high-temperature insulation class, heat-resistant mechanical seals).

Protection Rating: Motor protection rating should be at least IP68 (completely dust-tight and capable of prolonged submersion) to ensure safety during submerged operation.

Cooling System: For continuous operation or high medium temperatures, the motor may require an accompanying cooling jacket, utilizing external cooling water circulation.

Installation and Maintenance: Sufficient lifting space for maintenance must be considered. Long-shaft submersible pumps require ensuring shaft stability and vertical alignment.