Neutrals, asphaltene, sensitivity

The weight percents of the individual homologs in each specific-Z series (carbon-number distributions) were calculated from LV/EI/MS molecular-ion intensities assuming constant mole sensitivities for each specific-Z series. An invalid factor was inadvertently used in the previous conversion of the LV/EI/MS carbon-number distributions for the asphaltene neutral fraction to carbon-number distributions based on the total liquid. Consequently, the entries in the LV/EI/MS carbon-number distributions for Z(H), Z(O), and Z(S) asphaltene neutral aromatic compounds in References 35 and 47, the total weight percentages of these specific-Z series in References 35, 47, and 48, and the sums of these latter weight percentages reported in all these references should be multiplied by 0.892. 

Table I. Effect of Sensitivity Approximations on Quantitative Distributions for Asphaltene Neutrals by FI/MS.

For both the oil and asphaltene neutrals, Tables III and IV present in Columns 4, 7, and 10 the range in carbon numbers in Columns 5, 8, and 11 the range in molecular weights and in Columns 3, 6, and 9 the weight percents of the total liquid accounted for by each specific-Z series in Column 1. The results in Columns 6-8 and in Columns 9-11 in both tables were calculated from FI/MS and LV/EI/MS data, respectively, assuming constant mole sensitivities in a specific-Z series. 

The first step in systematic emulsion breaking is to characterize the emulsion in terms of its nature (O/W, W/O, or multiple), the number and nature of immiscible phases, the presence of a protective interfacial film around the droplets, and the sensitivity of the emulsifiers. In oilfield W/O emulsions, a stabUizing interfacial film can be formed from the asphaltene and resin fractions of the crude oil. This causes special problems because if the films are viscoelastic then a mechanical barrier to coalescence exists, which may be quite intractable and yield a high degree of emulsion stability. More detaUed descriptions are given in references [J33-J35]. Based on an emulsion characterization, a chemical addition could be made to neutralize the effect of the emulsifier, followed by mechanical means to complete the phase separation. 

---