Bubble point temperature

JFor boiling of mixtures, the saturation temperature (bubble point) of the final liquid phase (after the desired vaporization has taken place) is to be used to calculate the mean temperature difference. A narrow-boiling-range mixture is defined as one for which the difference between the bubble point of the incoming liquid and the bubble point of the exit liquid is less than the temperature difference between the exit hot stream and the bubble point of the exit boiling liquid. Wide-boiling-range mixtures require a case-by-case analysis and cannot be reliably estimated by these simple procedures. 

It is Eqs. 10.3-5 and 10.3-6 that are used in the algorithm of Fig. 10.3-5. Computer programs and MATHCAD worksheets for bubble point temperature, bubble point pressure, dew point temperature, dew point pressure, and isothermal flash calculations using the Peng-Robinson equation of state with generalized parameters (Eqs. 6.7-1 to... 

The temperature of the rectifying section pinch point is obtained from either a bubble-point temperature calculation on x,-, or a dew-point temperature calculation on y,>. The result is 126°F. Similarly, the liquid-distillate temperature (bubble point) and the temperature of the vapor leaving the top stage (dew point) are both computed to be approximately 123°F. Because rectifying section pinch-point temperature and distillate temperatures are very close, it would be expected that (/ ) i and would be... 

Figures 4.2 and 4.3 display the experimental set up for the room temperature bubble point tests. For all three weaves, 9 cm (3.5 in.) outer diameter (OD) 304SS screen samples were cut and fabricated to fit on top of a heavy flange. A single fillet weld was used to bond the screen to the flange and to bond a 0.318 cm (1/8 in.) thick cover ring on top of the screen as shown in Figure 4.2. The resultant OD and surface area of the screen exposed to the liquid was 6.35 cm (2.5 in.) and 20.25 cm (3.14 in. ), respectively. Visual observations during tests indicated adequate welding of the screen to the flange bubble breakthrough...

FIGURE 4.3 Schematic of Room Temperature Bubble Point Experimental Setup. 

FIGURE 4.6 Room Temperature Bubble Point Pressure as a Function of Surface Tension of Pure Fluids for the (a) 325 X 2300, (b) 450 x 2750, and (c) 510 x 3600 Mesh Screen Samples. 

Figure 4.4 illustrates this effect for a room temperature bubble point and reseal test where the corrected reseal pressure is superimposed on the raw DPT signal. As shown, the reseal pressure is always lower than the bubble point pressure. Unlike bubble point data reduction, the DPT across the screen carmot alone be used to determine screen reseal. Rather, time synchronization with the visualization system is required to determine the exact differential pressure across the screen at reseal. Sole reliance on visualization makes reseal point data inherently noisier than bubble point data. 

Figures 6.7a and b and 6.8a and b plot the experimentally obtained bubble point pressure as a function of the liquid screen side temperature and bulk liquid temperature, respectively for the 200 x 1400 and 325 x 2300 screens. The room temperature bubble point prediction curve is also plotted in these figures. The 200 x 1400 room temperature pore diameter is taken from Table 3.2. The results from Jurns and McQuillen (2008) are plotted in Figures 6.7b and 6.8b for comparison to the current data.

Third, for all liquid temperatures and for both pressurant gases, bubble point pressure does not scale with the mesh of the screen. This is the most complex trend of the original five parameters tested. The second finest 450 x 2750 mesh produced the highest bubble points, for both GHe and GH2. The 510 x 3600 mesh outperformed the 325 x 2300 mesh at LH2 temperatures, but the 325 x 2300 yielded higher pressures in room temperature liquids. The reason for this crossover in performance is due to the temperature dependence of the screen pore diameter and geometry of the actual L/V interface at breakdown, as mentioned previously. The 510 screen has the largest gain at LH2 temperatures over the room temperature bubble point. 

While previous statistical attempts at using SEM analysis to relate a 2D projection of the 3D pore structure proved unsuccessful, correlations do exist between the pore diameter and screen properties for all meshes examined in the current work. Figures 10.2 and 10.3 plot the effective pore diameter against the shute wire diameter and the square root of the number of pores per square inch of screen ( nwarp shute). respectively for the 26 screens that have room temperature bubble point data. Error bars are also plotted in both figures, but are barely distinguishable. 

This nonlinear equation can be solved for the temperature (bubble point). 

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