THE problem of making natural-gas gasoline that will pass the test for objectionable sulphur compounds, known as the " doctor test," has been in the past a matter of no importance to the manufacturers of casing-head or .absorption gasoline, because their market was limited to refineries, which mixed the product with "straight-run" gasoline and purchased it on a gravity or distillation basis. Recently an export market has opened for this type of gasoline, so it is now desirable that it pass tlle " doctor test."
The Bureau of Mines has worked out, at its petroleum station at Bartlesville, Okla., a cheap and efficient method for treating the gasoline to render it " sweet " to the doctor test. The method is, briefly, scrubbing the gasoline with a solution consisting of 2o per cent. caustic soda, 7 per cent. litharge, with 2 or 3 per cent. powdered sulphur added, then rewashing with water. The method of application will vary in different plants, as a wide variety of scrubbing installations could be used. One simple arrangement is to introduce the gasoline at the bottom of a steel tower packed with steel shavings, and filled three-quarters full of the solution, the gasoli..ne being drawn off at the top into a second tower containing water and steel shavings.
A fuller account is given in a recent report issued by the bureau.
CONSUMPTION OF REAGENTS USED IN FLOTATION.