Recovery curves, composites with

Specifying the hot utility or cold utility or AT m fixes the relative position of the two curves. As with the simple problem in Fig. 6.2, the relative position of the two curves is a degree of freedom at our disposal. Again, the relative position of the two curves can be changed by moving them horizontally relative to each other. Clearly, to consider heat recovery from hot streams into cold, the hot composite must be in a position such that everywhere it is above the cold composite for feasible heat transfer. Thereafter, the relative position of the curves can be chosen. Figure 6.56 shows the curves set to ATn,in = 20°C. The hot and cold utility targets are now increased to 11.5 and 14 MW, respectively. 

Figure 13. The composites were reinforced with 20 wt % filler and prepared by freeze-drying method (a) SSF composite (b) CB composite. Only T and o strain cycles are shown. R indicates the recovery curve after the samples were conditioned at 140 for 24 hours. Measured at 1 Hz and 140 C. (Reproducedfrom reference 28.)...

The integral in equation (6.2) was evaluated numerically for the retardation spectra obtained from master curves, together with ar from the time-temperature superposition. A typical result is demonstrated in Fig. 6.3(a), where recovery is shown for the DBDI/PTHFeso polymer, for a simulated constant rate of heating r = 0.1 K/s. This Figure also illustrates the definitions of two parameters used to compare the responses the temperature of maximum recovery rate Tmax and the width of the recovery window AT. These parameters of the SMPs were compared with respect to chemical composition and crosslink density ric, expressed as the number of moles of 3-point star crosslinks, per 100 g of polymer. 

Composite scrap still represents polymer with enhanced performance, and on the other hand only contains around 50%-80% of the recoverable energy of the polymer. Hence in the marginal zone of the recovery process with its diminishing return curve, composites may make more sense as recovered material than as recovered energy. Furthermore, long fibre scrap is more useful than short, in any cascade system of recycling. 

Where the cold composite curve extends beyond the start of the hot composite curve in Fig. 6.5a, heat recovery is not possible, and the cold composite curve must be supplied with an external hot utility such as steam. This represents the target for hot utility (Q niin)- For this problem, with ATn,in = 10°C, Qnmin 7.5 MW. Where the hot composite curve extends beyond the start of the cold composite curve in Fig. 6.5a, heat recovery is again not possible, and the hot composite curve must be supplied with an external cold utility such as cooling water. This represents the target for cold utility (Qcmin)- For this problem, with AT in = 10°C, Qcmm = 10-0 MW. 

Once the design recovery for an absorber has been established, the operating curve can be constructed by first locating the point X9, y2 ou the diagram. The intersection of the horizontal hue corresponding to the inlet gas composition yi with the equilibrium curve y° = F x)... 

Where the cold composite curve extends beyond the start of the hot composite curve in Figure 16.5a, heat recovery is not possible, and the cold composite must be supplied with external hot utility such as steam. This represents the target for hot utility (gumin). For this problem, with ATmin = 10°C, g=7.5 MW. Where the hot composite curve... 

The appropriate placement of distillation columns when heat integrated is not across the heat recovery pinch. The grand composite curve can be used as a quantitative tool to assess integration opportunities. The scope for integrating conventional distillation columns into an overall process is often limited. Practical constraints often prevent integration of columns with the rest of the process. If the... 

The crystallization temperature depends on the composition of the mixture to be treated. The cooling diagram shows that a eutectic exists between p-xylene and each of the other components of the mixture. In the case of the m, p-xyiene binary system, the eutectic contains 13 per cent p-xylene and melts at —52 C (Fig. 4.10). It separates two iiquidus curves ME in equilibrium with solid m-xylene, PE in equilibrium with solid p-xylene. Provided that the initial mixture contains more than 13 per cent p-xyleoe. crystals of pure p-xylene are obtained by cooling to — 52 and a mother liquor, whose composition is that of the eutectic. However, it qan be noticed (bat the existence of the eutectic leads to limited recovery, and that this recovery requires beat exchanges at low temperature. 

The same techniques cannot be applied to the case of sPS/aPS blends, as the two components have similar Tg values (less than 10 °C difference). A higher resolution of close Tg values can be derived from the isothermal heat capacity curves, measured in the vicinity of Tg by modulated DSC [20]. Furthermore, sPS and aPS, when annealed separately below Tg, exhibit in both DSC and modulated DSC distinct endothermic transitions owing to the enthalpy recovery [20,21]. Both methods, when applied to the sPS/aPS blends, give a single temperature for all compositions in agreement with the presence of a miscibility between the components. 

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