Effects　of　Different　Heavy　Crude　Oil　Fractions　on　the　Stability　of　Oil-in-Water　Emulsion—Ⅲ.　Effects　of　pH　on　the　interfacial　properties　of　heavy　crude　functional　fractions　and　water　system

摘要

In this paper, effects of pH on the interracial properties of heavy crude functional fractions and water system are investigated. The influence ofpH on π-A isotherms of acid fraction, basic fraction, amphoteric fraction and asphaltene is great. The interracial pressure of fractions increases in strongly basic conditions. The ζ(-80mv) of acid fraction is the largest under basic conditions (pH=11-12), with the result to show that the interfacial activity of the acid fraction is superior to that of other fractions. The results of model emulsions show that strongly basic conolition (pH≥ 11) is beneficial to oil-inwater emulsion stability. The interfacial activity of acid fraction and asphaltene is superior to that of other crude fractions.