Balanced composite curves

Figure 7.3 To determine the network area, the balanced composite curves are divided into enthalpy intervals.

Solution First, we must construct the balanced composite curves using the complete set of data from Table 7.1. Figure 7.5 shows the balanced composite curves. Note that the steam has been incorporated within the construction of the hot composite curve to maintain the monotonic nature of composite curves. The same is true of the cooling water in the cold composite curve. Figure 7.5 also shows the curves divided into enthalpy intervals where there is either a... 

Figure 73 The enthalpy intervals for the balanced composite curves of Example 7.2.

Figure 16.38 shows a heat pump appropriately integrated against a process. Figure 16.38a shows the overall balance. Figure 16.38b illustrates how the grand composite curve can be used to size the heat pump. How the heat pump performs determines its coefficient of performance. The coefficient of performance for a heat pump can generally be defined as the useful energy delivered to the process divided by the power expended to produce this useful energy. From Figure 16.38a ...

Figure 26.28a shows the limiting composite curve for the three operations from Table 26.5 (i.e. excluding the flowrate loss). Matched against the limiting composite curve is a water supply line that shows a change in slope where the flowrate loss occurs. The target flowrate can be determined by a mass balance below the pinch. 

In such a case, we create the balanced hot and cold composite curves. These correspond to eliminating the intervals that have utilities and hence end up only with interval El - 4 and El — 5. We need to create the balanced curves since the hot and cold utility loads are calculated for an HRAT and the partitioning into El s will be based on EM AT = TIAT < HRAT. 

We illustrate this case in Figure 8.13 for EM AT = TIAT — 25 °C which is less than H RAT = 30° C. Note that the balanced hot and cold composite curves are... 

Figure 2.14 illustrates the overall approach by pinch-point analysis. The first step is extraction of stream data from the process synthesis. This step involves the simulation of the material-balance envelope by using appropriate models for the accurate computation of enthalpy. On this basis composite curves are obtained by plotting the temperature T against the cumulative enthalpy H of streams selected for analysis, hot and cold, respectively. Two aspects should be taken into account ... 

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