This case study demonstrates how Flownex® can be used in evaluating the effectiveness of the maintenance work conducted during a half station shutdown outage by characterising a unit and comparing the performance of the unit with data before and after the outage.
The main challenge is to determine the effectiveness of the work conducted during a half station shutdown. This is normally a difficult task, since most external factors influencing the process (fuel quality, ambient conditions and process configuration) are not the same before and after the shutdown.
One of the major advantages by using Flownex® is that the performance of a unit today, can be compared directly with the performance of the same unit at some point in the past even though external factors (ambient conditions, coal quality) and process configuration (e.g. number of feedwater heaters in service) may differ. This is accomplished by characterising the model according to the historic unit and then applying the current external factors and process configuration to that model. In simple terms, this equates to a previous “version” of the same unit that is placed next to the current plant and is provided with the same environmental conditions, fuel and process configuration. The differences that is then observed in the change of the fundamental loss coefficients (AH dP, condenser pressure, ID fan vane positions) between the pre- and post-characterised units, is the actual mechanical changes that occurred due to degradation or maintenance.This method is very useful in evaluating the effectiveness of maintenance that has been performed, or to identify where actual degradation has occurred, without having the data clouded by external factors or varying process configurations
Flownex® can be used to investigate the effectiveness of the work conducted during a half station shutdown as all of the external factors can be taken into account and therefore a direct comparison is possible.