|Publisher||World Petroleum Congress||Language||English|
|Content Type||Conference Paper|
|Title||The Effect of Paraffin Wax in Asphaltic Bitumen and Its Estimation.|
|Authors||By W. H. Thomas, A.R.S.M., M.Inst.P.T.and H. E. Tester, B.Sc., A.M.Inst.P.T.|
|Source||1st World Petroleum Congress, July 18 - 24, 1933 , London, UK|
|Copyright||1933. World Petroleum Congress|
THE EFFECT OF PARAFFIN WAX IN ASPHALTIC BITUMEN AND ITS ESTIMATION
By W. H. THOMAS, A.R.S.M., M.Inst.P.T., and H. E. TESTER, B.Sc., A.M.Inst.P.T.
. THE effects of paraffin wax on the properties and behaviour of bitumen used for industrial purposes have caused considerable discussion and the views expressed are widely divergent. The effect of the method of distillation employed in the preparation of an asphaltic bitumen has been investigated, and while it is shown that the residual bitumens prepared by the various methods vary widely as regards ductility, it is significant that their wax contents are approximately constant. From the results obtained it would appear that the content of so-called " soft asphalt " is the predominating factor in determining the quality of the asphaltic bitumen obtained from a waxy stock. The estimation of wax in asphaltic bitumen may be carried out by two methods: (1) distillation at atmospheric pressure followed by precipitation of the wax from the distillate by means of a suitable solvent at low temperatures, and (2) treatment with sulphuric acid or by a precipitating solvent in order to remove bituminous compounds and then precipitation of wax from the oil obtained, by a solvent at low temperatures. The experimental results obtained indicate that the second method is not satisfactory, since the waxes obtained are invariably brown in colour and appear to contain resinous matter, while the waxes obtained by the first method are white. It is suggested that the brown waxes obtained could be purified by repeated precipitation, but this has been found to lead to low results. Distillation methods must of necessity involve a certain degree o£ cracking and hence a low result, and it is shown how by use of data obtained on the cracking of paraffin wax a fairly satisfactory estimate might be obtained of the " effective wax content " in an asphaltic bitumen.
. Some of the most interesting and difficult problems of petroleum chemistry concern the presence, behaviour and estimation of paraffin wax in crude oils, their distillates and residues. The lack of success which has attended the solution of certain aspects of the problems may be due to the fact that they have been attacked from the wrong point of view and should have been regarded from the standpoint of physical chemistry; in particular, wax as the dispersed component of a colloidal system, resinous and asphaltic compounds being the protective colloid and oil the dispersion medium. EFFECT OF WAX ON ASPIIALTS. The effect of wax on the properties and behaviour of asphaltic bitumen in use has long been a subject for discussion and the views expressed are somewhat divergent. Hausman,' for instance, considers that the contention-that crudes containing paraffin yield residues which are unsuitable for road construction-is not entirely correct. He states that the paraffin content is not the cause of the difficulty in producing a satisfactory residuu
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