Holding is a continuous process during the operation of the air cooled condenser (in power plant). The steam turbine is evacuating air, as well as the steam which powers the turbines. If holding did not occur, accumulate would result from the steam. This can form spots which in turn cause loss of performance. Loss of performance, of course, can hurt the overall operation from both a process sense and a pressure sense. Vacuums need 'just the right' pressure in order to work effectively and power the turbines which keep the system running in an air cooled condenser in power plant use.
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