Surface Condenser

These gases can also result from caused by the decomposition of water into oxygen and hydrogen by thermal or chemical reactions.
These gases must be vented from the condenser for the following reasons:
The gases will increase the operating pressure of the condenser. Since the total pressure of the condenser will be the sum of partial pressures of the steam and the gases as more gas is leaked into the system, the condenser pressure will rise. This rise in pressure will decrease the turbine output and efficiency.
• The gases will blanket the outer surface of the tubes. This will severely decrease the heat transfer of the steam to the circulating water. Again, the pressure in the condenser will increase.
• The corrosiveness of the condensate in the condenser increases as the oxygen content increases. Oxygen causes corrosion, mostly in the steam generator. Thus, these gases must be removed in order to extend the life of cycle components.