Project Synopsis

Rate an air-cooled condenser bank on the exhaust of a power generation steam turbine system.

Project Summary

AIR COOLED CONDENSER RATING

The client, a process equipment fabricator, contracted Process Engineering Associates, LLC (PROCESS) to rate an air-cooled condenser for service on a turbine exhaust stream.  Specifically, the client manufactures modular air-cooled heat exchangers.  They wished to verify the number of these modules that would be required to condense steam leaving a turbine.  The client requested sizing data for both nominal and maximum steam flow rates.  This application was for an installation in France with a very high design air temperature.  The original design goals included significant subcooling of the condensate with a low temperature approach.  Additional constraints included a maximum fan horsepower and a desired maximum number of modules.

PROCESS' licensed commercial computer process simulation software CHEMCAD, with its CCTHERM heat exchanger sizing module, were used to rate the heat exchangers for this service.  An iterative approach was required, calculating the overall heat transfer coefficient and duty with an assumed number of units.  This method was repeated until the required area and the assumed area were equal.  A proprietary in-house calculation method was used to validate the results of the simulation.

The model indicated that it was not feasible to achieve the required duty with the maximum design air temperature and maximum steam rate with the desired maximum number of modules.  Further simulation runs indicated that the addition of another fan to each module would allow the desired maximum number of units to achieve the design duty at the design maximum steam flow.  A recommendation was given to the client to proceed on that basis.

The model further indicated that the desired degree of subcooling was impractical with the design maximum air temperature.  At this temperature, the maximum number of units (with additional fans) would be required to condense the maximum steam rate with no subcooling.  Some subcooling will be possible with a lower steam rate or a lower air temperature.

Industry Type

  • Power Generation
  • Equipment Manufacturing

Utilized Skills

  • Heat transfer design
  • Independent design review
  • Unit operations optimization

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