CP table

The CP table. Identification of the essential matches in the region of the pinch is clarified by use of a CP table. In a CP table, the CP values of the hot and cold streams at the pinch are listed in descending order.  [c.366]

Figure 16.4a shows the grid diagram with a CP table for design above the pinch. Cold utility must not be used above the pinch, which means that hot streams must be cooled to pinch temperature by recovery. Hot utility can be used, if necessary, on the cold streams above the pinch. Thus it is essential to match hot streams above the pinch with a cold partner. In addition, if the hot stream is at pinch conditions, the cold stream it is to be matched with must also be at  [c.366]

Figure 16.4 The CP table for the designs above and below the pinch for the problem from Table 6.2. Figure 16.4 The CP table for the designs above and below the pinch for the problem from Table 6.2.
Figure 16.86 shows the cold-end design with the CP table. Below the pinch, adjacent to the pinch, CP a CPc- Again, the duty on units has been maximized according to the tick-oflF heuristic.  [c.371]

Figure 2 represents the main view of the model, including all the objects and relationships, the detailed definition of which is given in the standard draft ( 8.2.1 - cf table I). fhe object groups of figure 1 have also been represented on figure 2, for an easier comprehension. This main view is common to all the NDT methods.  [c.926]

Secrion lo. Alcohols. —OH. (cf. Tables IV, V. 536 537)  [c.335]

Section 12. Aldehydes. — CHO. (cf. Tables, pp. 539, 540)  [c.341]

Section 13. Ketones. C 0. cf. Tables IX, X, 541 - 542)  [c.345]

Section 15. Esters. — COOR. (cf. Tables, pp. 543-547)  [c.354]

Section 20. Amines, cf. Tables XVI -XVIII, pp. 550-553)  [c.372]

Section 25. Halogeno-hydrocarbons. cf. Table XXVI, p. 559)  [c.390]

Section 27. Ethers. ROR. cf. Table XXVIII, pp. 560 - 561).  [c.395]

Section 10. Alcohols. -OH. cf. Tables IV, V. 535 537)  [c.335]

Section 12. Aldehydes. -CHO. cf. Tables, pp. 539, 540)  [c.341]

Section 13. Ketones. C 0. cf. Tables IX, X, 541 542)  [c.345]

Section 15. Esters. —COOR. (cf. Tables, pp. 543-547)  [c.354]

Section i6. Ammonium salts, amides, imides, nitriles, cf. Tables XI, XII, pp. 543 545)  [c.359]

Section 20. Amines, (cf. Tables XVI-XVIII, pp. 550-553)  [c.372]

Section 21. Anilides. R-CONHC,Hj. (cf. Tables, pp. 543 -545)  [c.379]

Section 23. Nitro-compounds. R-NOj. (cf. Table XXI, p. 557)  [c.384]

Section 25. Halogeno-hydrocarbons. (cf. Table XXVI, p. 559)  [c.390]

Section 26. Hydrocarbons. CxHy. cf. Table XXVII, p. 560)  [c.393]

Section 27. Ethers. ROR. (cf. Table XXVIII, pp. 560 561).  [c.395]

The vibration frequencies of C-H bond are noticeably higher for gaseous thiazole than for its dilute solutions in carbon tetrachloride or tor liquid samples (Table 1-27). The molar extinction coefficient and especially the integrated intensity of the same peaks decrease dramatically with dilution (203). Inversely, the y(C(2jH) and y(C(5(H) frequencies are lower for gaseous thiazole than for its solutions, and still lower than for liquid samples (cf. Table 1-27).  [c.61]

Consideration of the results of Drain and Morrison for the low-temperature adsorption of nitrogen, oxygen and argon on rutile, serves to confirm the importance of reference to Point B when calculating the monolayer capacity from BET plots. The isotherms were all of well defined Type II, but each gave two almost linear BET plots a short one at low relative pressure and a longer one over the higher and more usual range of relative pressures. The former, which included point B, gave a value of which agreed well with tig, but the value of from the latter was significantly higher than tig (cf. Table 2.1).  [c.56]

Following Zsigmondy, early workers in the field assumed the pores to be cylindrical and the angle of contact to be zero, so that the meniscus was hemispherical. The mean radius of curvature r thus became equal to the radius of the pore less the thickness of the adsorbed film on the walls. By application of the Kelvin equation it was therefore possible to calculate the minimum radius of pores in which capillary condensation can take place, from the relative pressure at D, the lower limit of the hysteresis loop. General experience from the time of Anderson (working in Zsigmondy s laboratory) onwards, shows that this minimum radius varies from system to system, but is rarely below 10 A. The upper limit of the applicability of the Kelvin equation, r 250 A, is a practical one, set by the experimental difficulty of measuring very small lowerings of vapour pressure (cf. Table 3.8). The justification for defining mesopores by reference to the limits 10 to 250 A therefore rests on the fact that the classical capillary equations, especially the Kelvin equation, are applicable in this range.  [c.113]

One other cause of hysteresis remains to be mentioned. As was pointed out earlier (p. 177) the contact angle may be different as the mercury is advancing over or receding from a solid surface, and it depends also on the chemical and physical state of the surface the mercury may even react with the surface layer of the solid to form an amalgam. A change in 9 of only a few degrees has a significant effect on the calculated value of pore radius (cf. Table 3.15).  [c.186]

To test the feasibility of the idea, the solid chosen was a carbon black, composed of spherical particles which had been rendered microporous by controlled oxidation at 770 K. Since the particles were reasonably uniform in size, the external surface could be estimated by electron microscopy. The nitrogen isotherm was determined first when the micropores had been filled with nonane, and then after they had been progressively emptied by pumping at elevated temperatures, until finally they were completely empty (Table 4.6). The modus operandi was to expose the outgassed solid at 77 K to the vapour of n-nonane (from a reservoir of the liquid at room temperature), then allow the solid to warm up to room temperature, and finally to open up to the pumps to remove all adsorbate from the external surface. The nitrogen isotherm of this final sample is shown in curve A of Fig. 4.13, along with curves B, C and D which refer to successive stages in the removal of the n-nonane from the micropores by outgassing at successively higher temperatures (cf. Table 4.6). Isotherm E was obtained on the fully outgassed sample.  [c.212]

The values of external specific surface /C(ext) calculated from the slopes of the parallel branches of the o(,-plots are in close agreement (cf. Table 4.8, column 4) and the whole picture is therefore internally consistent the four isotherms represent different degrees of filling of the micropores with nonane, leaving the external surface unaffected.  [c.216]

The NMR speetra of the parent heteroeyeles cf. Table 7) eaeh eonsist of two multiplets,  [c.7]

Annelation increases the complexity of the spectra just as it does in the carbocyclic series, and the spectra are not unlike those of the aromatic carbocycle obtained by formally replacing the heteroatom by two aromatic carbon atoms (—CH=CH—). Although quantitatively less marked, the same trend for the longest wavelength band to undergo a bathochromic shift in the heteroatom sequence O < NH < S < Se < Te is discernible in the spectra of the benzo[Z>] heterocycles (Table 17). As might perhaps have been anticipated, the effect of the fusion of a second benzenoid ring on to these heterocycles is to reduce further the differences in their spectroscopic properties (cf. Table 18). The absorption of the benzo[c]  [c.14]

Figure 16.45 shows the grid diagram with a CP table for design below the pinch. Hot utility must not be used below the pinch, which means that cold streams must be heated to pinch temperature by recovery. Cold utility can be used, if necessary, on the hot streams below the pinch. Thus it is essential to match cold streams below the pinch with a hot partner. In addition, if the cold stream is at pinch conditions, the hot stream it is to be matched with also must be at pinch conditions otherwise, the AT in constraint will be violated. Figure 16.45 shows a design arrangement below the pinch that does not use temperature differences smaller than ATmin-  [c.367]

Solution Figure 16.8a shows the hot-end design with the CP table. Above the pinch, adjacent to the pinch, CPfjSCPc- The duty on the units has been maximized according to the tick-oflF heuristic.  [c.371]

Solution Figure 16.16a shows the streeun grid with the CP tables for the above- and below-pinch designs. Following the algorithms in Fig. 16.15, the  [c.380]

Contrary to what had at one time been supposed, the range of validity of the BET equation does not always extend over the range of relative pressures 0 05 to 0-30. In Fig. 2.7, which refers to the adsorption of nitrogen on pure sodium chloride, the straight line portion of the BET plot covers the relative pressure range 001 to OT the point where the adsorption has the value n (calculated from the plot) lies at a relative pressure of 005. On ungraphitized carbon black, Dubinin obtained a linear BET plot for nitrogen over the relative pressure range 0 005 to 0T5, which changed to 0 01 to 0-20 when the surface of the black was 80 per cent covered with a layer of pre-adsorbed methanol. There are numerous other examples (not only with nitrogen) where departure from linearity commences at relative pressures below 0-2 (cf. Table 2.1). Cases are also  [c.52]

In general one would expect a high value of A( to be associated with a high value of itself (cf. Table 1.1 and p. 10) which will be reflected in a high value of c. Thus a highly localized film is likely to yield an isotherm having a high value of c, whereas a largely mobile film should lead to a lower value of c. Both of the factors (a) and (b) should therefore cause the value of a to vary with the value of c. Such a variation is demonstrated, for example, by the set of isotherms of n-pentane in Fig. 2.17(a), which vary markedly in shape according to the nature of the adsorbent. The corresponding values of a (calculated from these and additional isotherms of pentane) show a marked correspondence with the value of c (Fig. 2.17(h) at low c-values (rounded knee) o varies rapidly with c, whereas at higher c-values a becomes almost constant. Moreover all the values of a arc in excess of the figure, 36-2 A, calculated from the liquid density at 293 K, which corresponds to nonlocalized adsorption.  [c.70]

Carbon dioxide is another adsorptive which finds relatively little use in surface area determination, despite its general experimental convenience and simple molecular structure not only is the possibility of chemisorption a complicating factor, but the high quadrupole moment of C02(3-1-3-4 X 10 e.s.u.) means that its adsorption isotherm is very sensitive to the presence of polar groups or ions in the surface of the solid. The quadrupole effect is clearly brought out in Fig. 2.20, due to Lemcoff and Sing, where the adsorbent was a well investigated nonporous silica (TK800, cf. Table 2.16). In curves (i) and (ii) the outgassing temperatures were 25°C and 1000°C, respectively, so that surface OH groups were present in (i) but absent in (ii). Removal of the OH groups led to a marked change in the isotherm from clear Type 11 (c = 21) to a near Type III (c = 4). Somewhat unexpectedly the a value, based on nitrogen, remained unchanged 22-2 A, but this may well have been fortuitous in view of the uncertainty attaching to the BET monolayer capacity when c is small.  [c.82]

Thus, whilst it is usualf to assume that 0 = 140°, the actual value almost certainly depends on the nature of the surface as well as on whether the mercury is penetrating or withdrawing, and an uncertainty up to 20 per cent must be reckoned with (cf. Table 3.14). Again, the surface tension of mercury is sensitive to contamination and it probably depends on the nature of the surface, whilst in extreme cases actual amalgamation can occur. The error in pore size arising from use of the conventional value y = 480 mN m is very difficult to assess quantitatively it probably varies from negligible to very large, depending on the nature of the solid and the care taken in the experimentation.  [c.190]

Annelation of a benzene ring on to the [Z>] faee of the heteroeyelie ring does not have any pronouneed effeet upon the ehemieal shifts of the heteroeyelie protons (cf. Table 8). The rather unexpeeted heteroatom sequenee for shifts to progressively lower field for both H-2 and H-3 remains NH[c.8]

See pages that mention the term CP table : [c.379]    [c.380]    [c.149]    [c.156]    [c.347]    [c.347]    [c.380]    [c.68]    [c.76]    [c.176]    [c.6]   
Chemical process design (2000) -- [ c.366 ]