Chapter 7: Experimental Data Results and Discussion
7.5 VLE in water solids n-octane Blends
Both silica sand and kaolin clay are added in the present study into water and n-octane blends mixture, to form a multicomponent mixture. P-T diagrams are investigated to establish the vapor pressure and its change with solids concentrations. Solid particles employed 70 wt % silica sand and 30 wt% kaolin clay. This solid blend is used to closely represent the solids in the NRU (See 5.1.1).
Figure 59 and Table 35 report VLE for 1.0 wt % n-octane mixture in water with 20 wt% of solids. One can, thus, see that the ππππ₯ is very close to the vapor pressure for 1.0 wt% n-octane in water without solids, and close as well to the ππππ₯ defined with the addition of
the n-octane and water vapour pressure. Thus, the 20 wt% does not have a significant influence on ππππ₯ and the n-octane/water blend continues to behave as a quasi-immiscible blend.
Figure 59. π·πππ for 1.0 wt% n-octane and various water-solid compositions in the 30
β to 110 β range. Notes: (a) Summation of water and octane saturation pressures represent a completely immiscible model (purple solid line), (b) 1080 rpm mixing speed is used, (c) Vertical bars indicate the standard deviation of three or more experimental repeats.
Table 35. n-octane 1.0 wt% + solids 1.0 wt% + water 98.0 wt% Experimental and Statistical data
Exp. Data (n-octane 1.0 % + solids 1.0 % + water 98.0 %) wt. 95% CI
Temperature (Β°C) P mix (psia) SD (Β±) SE LB UB
30 0.46 0.07 0.04 0.39 0.54
50 2.10 0.31 0.18 1.75 2.45 60 3.67 0.25 0.14 3.39 3.95 70 5.93 0.26 0.15 5.63 6.22 80 9.17 0.35 0.20 8.77 9.56 90 14.43 0.40 0.23 13.98 14.88 100 21.18 0.34 0.20 20.80 21.57 110 28.77 0.65 0.38 28.04 29.51
Table 36. n-octane 1.0 wt% + solids 20.0 wt% + water 79.0 wt% Experimental and Statistical data
Exp. Data (n-octane 1.0 % + solids 20.0 % + water 79.0 %) wt. 95% CI
Temperature (Β°C) P mix (psia) SD (Β±) SE LB UB
30 0.54 0.08 0.06 0.43 0.66 40 1.30 0.06 0.04 1.22 1.39 50 2.39 0.01 0.00 2.38 2.40 60 3.98 0.01 0.01 3.97 3.99 70 6.32 0.01 0.01 6.31 6.34 80 9.69 0.01 0.01 9.68 9.70 90 14.84 0.22 0.15 14.54 15.14 100 20.90 0.57 0.41 20.11 21.70 110 27.34 0.78 0.55 26.26 28.43
Figure 60 further report VLE for 2.0 wt % n-octane mixture in water with 20 wt% solids. Here again, there is no difference in the VLE with and without solids, as observed for 1.0 wt% n-octane in water.
Figure 60. π·πππ for 2.0 wt% n-octane and various water-solids compositions in the 30 β to 110 β range. Notes: (a) Summation of water and octane saturation pressures represent a completely immiscible model (purple solid line), (b) 1080 rpm mixing speed is used, (c) Vertical bars indicate the standard deviation of three or more experimental repeats.
Table 37. n-octane 2.0 wt% + solids 1.0 wt% + water 97.0 wt% Experimental and Statistical data
Exp. Data (n-octane 2.0 % + solids 1.0 % + water 97.0 %) wt. 95% CI
Temperature (Β°C) P mix (psia) SD (Β±) SE LB UB
30 0.45 0.06 0.04 0.33 0.56
40 1.23 0.09 0.07 1.05 1.41
50 2.28 0.05 0.03 2.19 2.38
60 3.82 0.03 0.02 3.77 3.86
80 9.44 0.08 0.06 9.29 9.60
90 14.71 0.00 0.00 14.70 14.71
100 21.29 0.16 0.11 20.99 21.60
110 29.01 0.08 0.06 28.85 29.17
Table 38. n-octane 2.0 wt% + solids 20.0 wt% + water 78.0 wt% Experimental and Statistical data
Exp. Data (n-octane 2.0 % + solids 20.0 % + water 78.0 %) wt. 95% CI
Temperature (Β°C) P mix (psia) SD (Β±) SE LB UB
30 0.52 0.18 0.13 0.16 0.88 40 1.20 0.04 0.03 1.12 1.29 50 2.14 0.20 0.14 1.75 2.53 60 3.56 0.38 0.27 2.81 4.31 70 5.76 0.44 0.31 4.89 6.63 80 9.02 0.43 0.31 8.17 9.86 90 14.09 0.48 0.34 13.15 15.03 100 20.19 0.63 0.44 18.96 21.42 110 26.92 0.62 0.44 25.70 28.15
Figure 61 and Figure 62 further show 4.0 wt% and 6.0 wt% n-octane in water blends with added 20 wt% solids. Here as well, there is a negligible difference on π·πππ recorded values, without and with 20 wt% solids.
Figure 61. π·πππ for 4.0 wt% n-octane and various water-solid compositions in the 30 β to 110 β range. Notes: (a) Summation of water and octane saturation pressures represent a completely immiscible model (purple solid line), (b) 1080 rpm mixing speed is used, (c) Vertical bars indicate the standard deviation of three or more experimental repeats.
Table 39. n-octane 4.0 wt% + solids 20.0 wt% + water 76.0 wt% Experimental and Statistical data
Exp. Data (n-octane 4.0 % + solids 20.0 % + water 76.0 %) wt. 95% CI
Temperature (Β°C) P mix (psia) SD (Β±) SE LB UB
30 0.61 0.06 0.04 0.52 0.69
40 1.34 0.03 0.02 1.29 1.38
50 2.38 0.02 0.02 2.35 2.41
60 3.94 0.03 0.02 3.90 3.98
80 9.68 0.03 0.02 9.63 9.72
90 14.90 0.02 0.01 14.87 14.93
100 21.26 0.12 0.08 21.10 21.43
110 28.58 0.21 0.15 28.29 28.87
Figure 62. π·πππ for 6.0 wt% n-octane and various water-solid compositions in the 30
β to 110 β range. Notes: (a) Summation of water and octane saturation pressures represent a completely immiscible model (purple solid line), (b) 1080 rpm mixing speed is used, (c) Vertical bars indicate the standard deviation of three or more experimental repeats.
Table 40. n-octane 6.0 wt% + solids 20.0 wt% + water 74.0 wt% Experimental and Statistical data
Exp. Data (n-octane 6.0 % + solids 20.0 % + water 74.0 %) wt. 95% CI
30 0.36 0.35 0.25 -0.13 0.85 40 1.09 0.29 0.21 0.68 1.49 50 2.13 0.35 0.25 1.64 2.62 60 3.73 0.51 0.36 3.02 4.43 70 6.09 0.64 0.45 5.20 6.97 80 9.44 0.68 0.48 8.50 10.38 90 14.64 0.68 0.48 13.70 15.59 100 21.16 0.77 0.55 20.09 22.23 110 28.90 0.97 0.68 27.56 30.24
Finally, Figure 63 and Table 41 reports 0.25 wt% n-octane in water with 20 wt% of solids. One can notice that ππππ₯ decreases in all cases with and without solids displaying a difference with the ππππ₯for the fully insoluble phases, with this being the result as explained in 7.2.2 of partial hydrocarbon miscibility at the lower hydrocarbon concentrations studied.
Figure 63. π·πππ for 0.25 wt% n-octane and various water-solid compositions in the 30 β to 110 β range. Notes: (a) Summation of water and octane saturation pressures represent a completely immiscible model (purple solid line), (b) 1080 rpm mixing speed is used, (c) Vertical bars indicate the standard deviation of three or more experimental repeats.
Table 41. n-octane 0.25 wt% + solids 20.00 wt% + water 79.75 wt% Experimental and Statistical data
Exp. Data (n-octane 0.25 % + solids 20.00 % + water 79.75 %) wt. 95% CI
Temperature (Β°C) P mix (psia) SD (Β±) SE LB UB
30 0.47 0.04 0.03 0.42 0.52
40 1.23 0.01 0.00 1.22 1.24
50 2.21 0.05 0.04 2.14 2.28
60 3.54 0.09 0.06 3.42 3.66
80 7.99 0.01 0.01 7.98 8.01
90 11.98 0.04 0.03 11.92 12.04
100 16.94 0.23 0.16 16.61 17.26
110 22.81 0.47 0.33 22.15 23.46
Therefore, one can conclude that for all n-octane/water blends studied, kaolin clay and silica sand blend at 20 wt% does not influence the π·πππ. While sand particles are massive, kaolin clay particles display a BET specific internal surface area and, in principle, could adsorb hydrocarbon species, affecting the vapor pressure measured (See 5.1.1). However, despite this, it appears hydrocarbon adsorption on kaolin clay while present is not significant enough to affect π·πππ.
7.6 Conclusions
(1) Pressure data from runs in the CREC-VL-Cell can be corrected using an βAir contained fraction correctionβ factor.
(2) VLE measurements in the CREC-VL-Cell were successfully validated using pure n-octane, pure n-hexane and pure water. This was the case, given the good agreement of measurements with data reported in the technical literature
(3) VLE measurements in the CREC-VL-Cell for n-octane/water blends showed consistency with the insoluble phase model, with this being true for all n-octane concentrations, except for the 0.5 wt% lowest n-octane concentration.
(4) VLE measurements in the CREC-VL-Cell using SN and water blends were investigated using 2.5 wt% SN in water, in the 0 - 1200 rpm impeller speed range. It was proven that the 1080rpm impeller speed provides adequate mixing, preventing cavitation.
(5) VLE measurements using 0.5 wt to 97.5 wt% SN in water blends displayed a π·πππ
consistently in agreement, with the insoluble two liquid phase model.
(6) VLE measurements employing n-octane in water, with a 20 wt% added silica sand-kaolin clay solids, showed no influence of solids on ππππ₯ measurements.