From Oil Field to Engine.
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How the Supply of Petrol is Distributed to the Consumer.
The familiar oblong tins of motor spirit can be purchased in every village as easily as a loaf of bread; few of the large army of users, however, give a thought to the immense organisation, backed up by unlimited capital, that places this necessary product at their disposal. Thanks to the courtesy of the General Petroleum Co., Ltd., a member of the staff of "THE Commesem MOTOR" was enabled last week to follow the whole of the processes. Into the various technical operations it is not our present intention to enter, but just a few words of what happens at the oil fields in Sumatra and Borneo are needed to make clear what follows. When the oil conies to the surface at the oil field it is a dark viscous fluid, and it has to be distilled several times before the whole of its commercial constituents are available. The oil is pumped into a circular tank (of moderate diameter, but comparatively great depth), having the shape of an inverted cone at its base, from which issues a pipe with a draw-off valve. The tank is termed a " mixer," and carries across its diameter, just above the cone, a shaft, with paddles attached. The shaft is driven from the exterior by a steam engine with connecting belt. By means of compressed air, acid, which has been previously warmcd by steam, is forced into the miser. The oil and acid are agitated by the paddles and then permitted to settle. The acid being the heavier product, sinks to the point of the cone and is drawn oil. This operation is repeated with soda, this in its turn being drawn off by a second valve. From the mixer the oil is led to the still, where it is heated by steam, and the lighter product passes over in the form of vapour to the worm condenser; this latter is, of course, jacketed with cold water. From the condenser it is led into a tank placed at some height from the ground. A feature of the manufacture should here be noted. This is the application of the process known as fractional distillation. Spirit of, perhaps, 0.750 sp. gr., but built of various constituent hydro-carbons ranging between 0.670 and 0.780 sp. gr., is put into the still and subjected to heat. Although the spirit appears uniform, by the gravity test, different increases of temperature cause different percentages of various gradually increasing densities to distil over, according to the boiling points. By a system of controlling ducts, to direct successive ranges into several receivers, the spirit is sorted out into three or more qualities with relatively small differences in either the gravities or the vapourising characteristics. In the still all is apparently good, but is built up of numerous grades of spirit, and it is only by this system of fractional distillation that it can be divided. Many hydrometer tests show the proper moment to shut off for the heavier product. The operation thus described takes place at the oil field, as it is more economical to refine on the spot than to carry the crude oil to this country. The General Petroleum Co. has installed a large refining plant at Thames Haven, but this is only used in case of emergency. The crude oil in the course of the various refining processes gives paraffin wax, pitch, lubricating oil, solar oil for enriching gas, kerosene, an oil known as intermediate, and the benzine class, from which, finally, motor spirit is obtained. From the oil fields the spirit is brought to this country in tank steamers of enormous capacity; some 30 of these are in constant use throughout the world by the G.P.C., Ltd., and its linked organisations. The steamers come up the river Thames as far only as Thames Haven, a few miles from the Nore, Government regulations not permitting a nearer approach to the Metropolis. Upon reaching the pier
(seen beyond the steamer in Fig. 4), the steamer is berthed, and every fire on board has to be put out before the spirit can be pumped out. A steam pipe is led from shore along the pier to the pumps aboard the steamer. The pumps drive the spirit up to the end of the pier to the special valves there (see Fig. t), where large pipes convey it to the five huge storage tanks on shore (Fig. 2). From the storage tanks it is pumped to subsidiary tanks, whence the 40-gallon steel barrels are filled (Fig. 3). These barrels are used for delivering to customers in bulk around the coast by small steamers (Fig. 4), or to those partsof the country by railway where the local regulations permit of delivery in bulk.
We now come to the purely retail portion of the business, which entails the most trouble to all concerned and adds something like an eighth of the cost. The distributing depot for London adjoins Ikest Ham station, on the L.T. and S. Railway, and possesses its own private siding. The spirit is filled into railway tank wagons at Thames Haven, run up to West Ham, and, upon arrival at the siding, is pumped into underground storage tanks. At this dep6t are stored thousands of the familiar red oblong tins, each to contain
two gallons. Each tin is carefully washed out with fresh petrol, stood up to drain, labelled, and then passed on to the filling benches. All the old tins are subjected to the same processes, and, in addition, have the old labels scraped off and are repainted (Fig. 5). Similar overhead tanks to those shown in Fig. 3 are filled by hand pumps, whence the spirit is led by a large diameter pipe to the automatic measurers above the benches (Figs. 6 and 7). The spirit enters the measures from below, and, when tilled, the surplus rises in thin glass tubes at the top of each measure. These tubes can be well seen in Fig. 7. Below each measure is a threeway cock, six or eight being coupled by a long flat rod. In the first position of the cocks, spirit is admitted from tank to the measures; hi the second the surplus amount is drained away to an underground tank, in the third we cocks are opened to pipes in the mouth of each tin, and six or eight of the latter are simultaneously tilled. The brass caps are then screwed on, with one or two leather washers between as may be necessary, sealing wires passed through the cap and the tin, and the seals clamped on with a pressing tool. To ensure that each cap is spirit tight, the tins are laid upon their sides as in the front of Fig. 5. The weight of the superincumbent tins soon reveals any leakage, and the faulty tins are removed for further treatment. The tins are finally placed four in a box, and are then ready for delivery to customers throughout London and the provinces either by the company's own vans or by railway vans (Fig. 6). The measures previously mentioned are thoroughly cleaned from end to end each morning, and are carefully tested for the correct capacity once each month.
In view of the recent utterances with respect to a possible shortage of motor spirit supplies it was interesting to learn the views of one of the higher officials of the G. P. Co., Ltd., who may well be considered an expert in all matters relating to petroleum products. In reply to a question as to there being a motor spirit famine in the near future, this gentleman scouted with derision the mere thought of what he
termed "a ridiculous supposition," and emphatically asserted that for very many years the supplies could more than keep pace with the demand. The occasional difficulty in securing the quantities desired in some districts was in no way due to inability of refiners to bring refined spirit to this country but rather to varying regulations of railway companics, steamship companies and local authorities. For long distances it did not pay the refiner or the retailer to forward by railway in less than one ton lots, because of the heavier proportionate charges smaller quantities had to bear. It was often necessary to wait some days before orders could be sent out to certain neighbourhoods and thus send enough to take advantage of the ton rate.
In our visits to Thames Haven and West Ham we were highly impressed by the care taken at every stage to ensure cleanliness and also by the numberless and, as some might suppose, needless precautions to prevent a single drop of water reaching the 2-gallon tins or the 40-gallon barrels, but we think we have shown sufficient to prove that the user is getting full value for money when he purchases a 2-gallon
tin of Shell motor spirit. " VREAITCII."