Shifted temperature

Set up shifted temperature intervals from the stream supply and... 

In each shifted temperature interval, calculate a simple energy balance from... 

First, determine the shifted temperature intervals T from actual supply and target temperatures. Hot streams are shifted down in temperature by and cold streams up by AT J2, as detailed... 

Next, we carry out a heat balance within each shifted temperature interval according to Eq. (6.1). The result is given in Fig. 6.17. Some of the shifted intervals in Fig. 6.17 are seen to have a surplus of heat... 

TABLE 6.3 Shifted Temperatures for the Data from Table 6.2... 

Now, carry out a heat balance within each shifted temperature interval, as shown in Fig. 6.20. 

The grand composite curve is obtained by plotting the problem table cascade. A typical grand composite curve is shown in Fig. 6.24. It shows the heat flow through the process against temperature. It should be noted that the temperature plotted here is shifted temperature T and not actual temperature. Hot streams are represented ATn,in/2 colder and cold streams AT iJ2 hotter than they are in practice. Thus an allowance for ATj in is built into the construction. 

The shaded areas in Fig. 6.24, known as pockets, represent areas of additional process-to-process heat transfer. Remember that the profile of the grand composite curve represents residual heating and cooling demands after recovering heat within the shifted temperature intervals in the problem table algorithm. In these pockets in Fig. 6.24, a local surplus of heat in the process is used at temperature differences in excess of AT ,in to satisfy a local deficit. ... 

Figure 6.30 shows the grand composite curve plotted from the problem table cascade in Fig. 6.186. The starting point for the flue gas is an actual temperature of 1800 C, which corresponds to a shifl ed temperature of (1800 — 25) = mS C on the grand composite curve. The flue gas profile is not restricted above the pinch and can be cooled to pinch temperature corresponding to a shifted temperature of 145 C before venting to the atmosphere. The actual stack temperature is thus 145 + 25= 170°C. This is just above the acid dew point of 160 C. Now calculate the fuel consumption ...

Figure 15.1a shows a single-stage evaporator represented on both actual and shifted temperature scales. Note that in shifted temperature scale, the evaporation and condensjftion duties are shown at different temperatures even though they are at the same actual temperature. Figure 15.16 shows a similar plot for a three-stage evaporator. 

Figure 15.1 The representation of evaporators in shifted temperatures. (Repnnted from Smith, R., and Jams, P. S., The Optimal Design of Integrated Evaporation Systems, Heat Recovery Systems and CHP, 10 341, 19, with permission from Elsevier Science Ltd.)...

Set up shifted temperature intervals from the stream supply and target temperatures by subtracting ATmin/2 from the hot streams and adding A/2 to the cold streams (as in Figure 16.14b). 

Table 16.3 Shifted temperatures for the data from Table 16.2.

Note that T represents shifted temperatures for the process streams. Allow Arml /2 = 5°C for the steam side. 

The isomer shift contains a contribution from the thermal motion of the individual atoms in the absorber, the second-order Doppler shift, which makes the isomer shift temperature-dependent ... 

The rate of heating is variable. The slower this rate the better, because fast heating will shift temperatures higher and cause the size of the peak to increase. The rate of heating during calibration should equal the rate of heating during sample analysis. 

To achieve this composition, part of the gas flows to the shift converter and, reacting there with the superheated steam, produces CO and CO2. There is a heat exchanger to raise the temperature of the compressed gas to the shift temperature the heat comes from the shift reaction. The gas is introduced in a ZnO column, to eliminate sulfur traces, then is cooled with water, and passes through the C02 removal column. The CO2 is absorbed by 5°C water at 50 atm, and the gas is now ready for synthesis. 

Table 10.1 Activities of supported gold catalysts prepared by different methods (3% Au) for the water-gas shift temperatures for 50%...

Imaeda S9) investigated the chlorine and the bromine NQR in alkali chlorates and alkali bromates at 0 °C as a function of impurity concentration. Brom-ates, chlorates, and nitrates served as impurities. The results of Imaeda s investigation are given in Table VI.2. There is a considerable frequency shift, which is mostly negative (decrease in frequency) if the impurity ions are larger in size than the host ions. In cases where the impurity is smaller than the host ion, the frequency increases. Imaeda assumes that the distortion of the electronic wave functions about the impurities is responsible for the frequency shift. Temperature effects are ruled out since the impurity shift in the bromates... 

Considering the data scatter at the threshold end of the master curves, it is not possible to distinguish one method of normalization over the other. In fact, for low M, networks it can be argued that the small differences between the two theories will not be detectable for characteristically scattered measurements such as tearing. Over the entire Tg shifted temperature range, however, it is obvious that the normalization yields less scattered data and a better defined master curve. 

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