Metal pall rings

Once  this  curve  fit has  been  performed, then determining

the absolute values of the front factors AL, AV, and AM pro- ceeds by analyzing a different experiment or set of experi- ments where the contribution of the inpidual phase resis- tances to the overall resistance is different。  Typically,  we have accomplished this by looking at CO2 absorption into aqueous amine or aqueous caustic solutions。 We use the mass-transfer correlations regressed from the binary distillation experiments to predict the performance of  the  CO2  absorber (and sometimes the stripper) using the Aspen Rate Based Distillation module。2 Initially, the front factors values are fixed at AL ¼ 1, AV0 , and AM0  。 The predicted temperature profile,  out- let CO2 concentration, and outlet amine loading are noted, and their   deviation   from  experiment   recorded。   If  necessary, the

front factor AL  is adjusted to some new value, keeping AV0   and

fixed。  The  reader  should  recall  that  AM0

¼  ALAM   and that

¼ AV/AL。  We  typically  use  an  interval  halving  method to

determine the best value for AL。 There is some judgment involved in deciding what value for AL is best overall as the analysis of inpidual experiments oftentimes leads to a  spread in AL values。 A flow diagram outlining the fitting process to identify AL, AM, and AV  is shown in Figure 

Data Sources and Data  Correlation

hHETPi data for binary distillation systems and tempera- ture profile/amine loading/outlet sour gas composition data from acid gas absorption/stripping experiments were col- lected  for  the  packing  types  under  study here。9–12,20–22,39–63

The data for the various packing  families  were inpidu- ally analyzed using the methodology outlined above。 Several ad hoc limiting conditions were placed upon the power-law

Figure 5。 Diagram showing the workflow for the data fitting procedure proposed in this article。

Figure 6。 Parity plot comparing the calculated hHETPi to the experimentally measured hHETPi for sheet metal structured packings of the MEL- LAPAK/FLEXIPAC  type。

Figure 8。 Parity plot comparing the calculated hHETPi to the experimentally measured hHETPi for metal Pall rings random packing。

Data for both the ‘‘Y’’ and  ‘‘X’’  packing  configurations were used in the  regression。

Figure 7。 Parity plot comparing the calculated hHETPi to the experimentally measured hHETPi for metal IMTP random packing。

Figure 9。 Parity plot comparing the calculated hHETPi to the experimentally measured hHETPi for metal gauze structured packings in the X configuration (BX, DX, and EX)。

Figure 10。 Comparison of correlation predictions with experimental data for metal IMTP。

(a) Data of Wang et al。55 for total reflux distillation of benzene/toluene at 760 torr。 (b) Performance data for IMTP 40 random packing in ethylbenzene/styrene service。56 (c) Data of Wagner et al。43 for total reflux distillation of cyclohexane/n-heptane at 250 torr。 (d) Data of Wang et al。55 for total reflux distillation of carbon tetrachloride/benzene at 760 torr。 Correlations used in these calculations: Bravo and Fair,4  Onda et al。,3  and Billet and   Schultes。5

Figure  6  is  a  parity  plot  of  the  predicted  values        for

hHETPi vs。 the reported values for the various MELLA- PAK/FLEXIPAC  family  of  sheet  metal  structured packings。