Custom Hydrogen Gas‑to‑Water Cooler For Thermal Power Station Generator Overhaul Replacement
Thermal power plant turbo‑generators convert thermal energy into electricity. Large‑capacity units produce massive heat loss from stator winding, rotor winding and stator core. Generator cooling system removes this heat to keep winding insulation within safe temperature range. Main cooling technologies widely adopted in thermal power stations: hydrogen cooling, hydrogen‑water‑hydrogen cooling, water‑hydrogen‑water cooling. VRCOOLER supplies finned‑tube hydrogen coolers and auxiliary heat exchangers for thermal power generators, offering 1:1 equivalent replacement based on old equipment or technical drawings for new construction and unit overhaul projects.
Main Cooling Types for Thermal Turbo‑Generator
Full Hydrogen Cooling (H‑H‑H) Hydrogen cools stator winding, rotor winding and stator core. Hot hydrogen passes through hydrogen coolers (gas‑to‑water finned tube heat exchangers). Features low wind‑age loss, high cooling efficiency. Widely used for medium‑large thermal generating units.
Hydrogen‑Water‑Hydrogen Cooling (H‑W‑H) Stator winding adopts inner de‑ionized water cooling; rotor winding and stator core are cooled by hydrogen. Balances cooling performance and equipment investment, common for 200‑300MW thermal units.
Water‑Hydrogen‑Water Cooling (W‑H‑W) Both stator and rotor hollow conductors are cooled by de‑ionized water; stator core uses hydrogen cooling. Applied for large‑capacity 600MW‑1000MW ultra‑supercritical thermal power generators.
Closed Air‑to‑Water Cooling Mainly for small‑size thermal generators. Not economical for large MW‑level units due to poor heat transfer performance.
Core System Components (Hydrogen‑cooled generator as reference)
Hydrogen Cooler (Finned‑tube heat exchanger) Key heat‑exchange device. Hydrogen flows outside finned tubes; cooling water circulates inside tubes. Vertical or horizontal structure, mounted inside generator end housing. Strict helium leak test required.
Gas‑tight generator casing Maintains positive hydrogen pressure, prevents air ingress and hydrogen leakage.
Hydrogen circulating blowers Drive forced hydrogen circulation inside generator cavity.
Shaft seal‑oil system Blocks hydrogen leakage through rotating shaft clearance, critical explosion‑proof component.
Hydrogen handling auxiliary system Hydrogen dryer, CO₂ purging module, gas sampling & purity monitoring unit, pressure regulating valves, safety relief devices.
De‑ionized water cooling subsystem For inner‑water‑cooled winding type: heat exchanger, water tank, ion exchanger, filter, conductivity & temperature transmitters.
Monitoring & alarm instruments Hydrogen purity, dew point, pressure, winding temperature, differential pressure sensors for interlock protection.
Critical Design & Operation Points
Hydrogen tightness safety Hydrogen‑air mixture brings explosion risk. Tube‑to‑tube‑sheet expanded‑weld joint; full helium leak inspection during manufacturing. Keep positive hydrogen pressure inside casing all the time. Apply CO₂ intermediate purging before filling or discharging hydrogen gas.
Strict hydrogen‑side pressure drop control Excessive resistance reduces hydrogen circulation flow, leads to over‑temperature of rotor and stator.
Anti‑vibration structure Turbo‑generator runs at high speed. Reinforced support for tube bundle to avoid tube fatigue crack and water leakage under long‑term vibration.
Dew‑point & condensation prevention Control hydrogen dew‑point via hydrogen dryer; avoid moisture condensation damaging winding insulation.
Maintainability for power‑plant overhaul Water‑side accessible for chemical cleaning; removable bundle structure preferred.
Main Advantages of Hydrogen Cooling for Thermal Generators
Hydrogen thermal conductivity is approx. 7 times higher than air; much lower wind‑age loss improves unit overall efficiency
Hydrogen is dry and non‑corrosive, extends insulation service life
Realize compact structure for large‑capacity turbo‑generators
Common Risks & Countermeasures
Hydrogen explosion hazard: continuous purity online monitoring, positive casing pressure, standardized purging procedure.
Cooler tube leakage: helium leak test pre‑delivery; regular inspection during shutdown overhaul.
Dew‑point over‑limit: keep hydrogen dryer working properly.
