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MR. MEGAWATT

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

if it was the cause for the change, as shown in Figure 2. Even though the condenser inlet temperature was increasing, it did not look like all the pasta was in the right pot. Brian and I asked for some Historical Plant Data and started working. The process we chose to use was to start with our thermodynamic box around the whole cycle and move the box 20 ENERGY-TECH.com

in around the components. Therefore, the starting point was the condenser cooling water inlet. First we wanted to characterize the relationship between the circulating water inlet temperature and the condenser pressure. This would tell us what condenser pressure was to be expected at a given load over the range of inlet temperatures. Once we had established the condenser expected performance, we would examine the relationship between the condenser pressure and plant output at a constant thermal input. Having all this information would be a first step in diagnosing the problem. Figure 3 shows the curve we developed to characterize the condenser performance. We also could have used vendor curves, but often the as-built performance is different than the theoretical performance provided by the vendor. Figure 4 shows the curve we developed to characterize the turbine performance with respect to condenser pressure. We also could have used the vendor curves here, but they do not always accurately represent actual plant performance with respect to condenser pressure. Using these two relationships, we could then take a look at how the condenser was performing. Figure 5 shows the expected condenser pressure (orange line) and the actual condenser pressure (blue line). It is clear that that the actual condenser pressure started increasing with respect to the expected condenser APRIL 2015

Profile for Energy-Tech Magazine

April 2015  

Heat Exchangers – Retrofit/Rebuild/Equipment Upgrade – Bearings – Turbine Tech: Steam – ASME: Combined-Cycle Plants

April 2015  

Heat Exchangers – Retrofit/Rebuild/Equipment Upgrade – Bearings – Turbine Tech: Steam – ASME: Combined-Cycle Plants

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