THE results obtained in producing lubricating oils, especially those of high viscosity, by refining according to the Edeleanu process, are shown in the form of tables. In particular two new variations of this process are described, consisting in the treatment with liquid sulphur dioxide at increased temperatures, or with mixtures of liquid sulphur dioxide with benzole. A modern Edeleanu plant permits of the employment of pure sulphur dioxide as well as of various mixtures of benzole and sulphur dioxide as extraction agents and accordingly becomes so flexible that any mineral oil products, from gasoline to heavy lubricating oil, can be put through. Finally, based on practical motor tests it is demonstrated that extraordinarily good motor oils can be produced by the Edeleanu process, even when starting from not particularly favourable distillates.
The application of the Edeleanu process to the refining of kerosines has been known for a long time and has been accepted by the industry throughout the world. The process has also been applied to the refining of lubricating oils, and several lubricating oil plants have been operating for many years, principally in the United States.
Recent developments in the design of motors, increasing compression ratios, which necessarily increase also the bearing pressures, required more highly refined motor oils and new specifications.
In view of this tendency, modifications of the Edeleanu process have been developed which have increased the flexibility of the process and now enable the refiner to meet every possible specification.
It may therefore be desirable to submit some results of the Edeleanu treatment of lubricating oils which have partly been obtained from oils on the European market.
The advantages of the Edeleanu process, using liquid sulphur dioxide, which is an extremely selective solvent of low price and of easy manufacture anywhere, low viscosity combined with high specific gravity and low boiling point (from which follows that it can most readily be recovered from all kinds of oils), are naturally retained by the new processes. They are even increased by the two new modifications: extraction by means of benzole-S02-mixtures and extraction at increased temperatures. The new plants are designed in such a manner that they are equally suitable for carrying out not only the new but also the old method of treating.
The plant has been given the greatest flexibility. All products from gasoline to the heaviest residual oils can be refined in one plant which can be changed from one product to the other in the shortest time. The plant is therefore capable of the most general application and also has the greatest adaptability for meeting any future market developments. It is certain that the physical separation of mineral oils and their fractions will be necessary regardless of the products