Valves play a critical role in the power sector, widely used in power generation, transmission, and auxiliary systems. Their performance and reliability directly impact the safety and efficiency of power plants. Below are the key applications and types of valves in the power industry.
Boiler System
Main Steam Valve: Controls high-temperature, high-pressure steam (up to 600°C, 25MPa+) entering the turbine; requires heat-resistant materials (e.g., chromium-molybdenum steel).
Feedwater Control Valve: Precisely regulates boiler water flow to prevent dry firing or overflow.
Safety/Relief Valve: Rapidly releases steam in case of overpressure to protect pipelines and equipment.
Drain Valve: Removes condensate (e.g., during turbine startup).
Turbine System
Globe/Isolation Valve: Cuts off steam flow during maintenance (e.g., turbine inlet valve).
Reheat Steam Valve: Controls reheat steam flow to improve thermal efficiency.
Cooling System
Butterfly/Gate Valve: Used in circulating water pipelines to regulate cooling water flow (e.g., condenser cooling).
Primary Loop System
Nuclear-Grade Gate/Globe Valve: Radiation-resistant, high-temperature and high-pressure resistant, used in reactor coolant pipelines (e.g., main pump isolation valve).
Safety Valve: Prevents overpressure in the primary loop (must comply with ASME III standards).
Secondary Loop System
Turbine Bypass Valve: Rapidly diverts steam to the condenser during emergencies to prevent core overheating.
Emergency Systems
Rupture Disk Valve: Instantly opens during severe accidents to inject coolant (e.g., AP1000 passive safety system).
Hydropower
Butterfly/Ball Valve: Controls water flow to turbines and provides emergency shutoff (e.g., penstock valves).
Pressure Regulating Valve: Adjusts water flow to stabilize power output.
Concentrated Solar Power (CSP)
Molten Salt Valve: Handles high-temperature molten salt (500°C+) in thermal storage systems.
Fuel Supply (Coal/Gas)
Pulverized Coal Valve: Controls coal powder delivery (requires wear-resistant design).
Gas Shutoff Valve: Quickly cuts off natural gas supply (e.g., gas turbine protection).
Flue Gas Treatment (Desulfurization/Denitrification)
Slurry Valve: Corrosion-resistant (e.g., rubber-lined butterfly valves in FGD systems).
Dampers: Isolates flue gas passages (for maintenance).
Compressed Air System
Pressure Reducing Valve: Maintains stable instrument air pressure.
Gate/Globe Valve | Main steam pipelines, high-pressure isolation | High temp/pressure resistance, low leakage (metal seal) |
Ball Valve | Fast shutoff in gas/fuel systems | Fireproof/anti-static design, quick action (<1 sec) |
Control Valve | Feedwater/steam flow regulation | High precision (±1%), anti-cavitation |
Safety Valve | Boiler/pressure vessel protection | Accurate set pressure, high discharge capacity |
Special Material Valves | Nuclear/corrosive media | Nuclear certification (ASME III), radiation-resistant materials |
Harsh Condition Adaptation: Valves for ultra-supercritical units (700°C+) require advanced heat-resistant alloys.
Smart Valves: Integrated sensors for remote monitoring (e.g., position, temperature feedback).
Environmental Compliance: Zero-leakage designs (e.g., bellows-sealed valves) to minimize media loss.
Lifespan & Maintenance: Nuclear valves must last 60+ years with minimal downtime.
Valve selection in the power industry must consider media parameters (temperature/pressure/corrosiveness), response speed, sealing class, and compliance (e.g., API, ANSI, GB standards) to ensure safe and efficient operation.