Advances in the refining art promise almost complete flexibility of refining control, thereby permitting production of any desired percentage of any one of the most important products, and thus relieving storage problems created by seasonal demands. Expected also is satisfactory commercial production of gasoline from the heaviest residual fuel oils ; utilization of almost any crude oil to make the highest range refined products—hitherto practically impossible because of peculiar characteristics of some crudes— and the production, without further treating of high octane-num ber motor fuel and aviation fuel.
One of the most significant angles to the development of ioo octane fuels was the fact that by using them the overall efficiency performance of the gasoline engine closely approached, if it did not equal, that of the Diesel engine. Formerly, the great ad vantages of the Diesel were its lighter engine weight per horse power and its lower specific fuel consumption.
The promised volume production of high octane-number gaso line has given the automobile engine designer a chance to enter new realms of achievement. While improvement in octane-number has been brought about to a considerable extent by cracking and polymerization, one of the chief contributions to this important result was the conception of what actually caused knocking in an engine, and the subsequent research to find a remedy. This brought about the use of additional organic compounds of lead— notably tetraethyl lead. Perhaps 8o% of all the gasoline sold through American filling stations in 1938 contained tetraethyl lead. The use of this and other high anti-knock fuels brought an increase in power with a great decrease in both the size and the weight of the automobile engine, with resulting economy to the automobile user.
Another notable contribution of science of direct benefit to the motoring public was the development on a large scale of meth ods for stabilizing gasoline by removing small amounts of hydro carbons of very low boiling point, and thus reducing vapour lock. This contribution made possible the development of gasolines which gave dependable service in winter weather; and this, like many other fuel improvements, made its contribution to the ad vances in the design of the gasoline engine. In this same class, perhaps, should be placed the discovery of those chemical inhibi tors against the oxidation of gasoline in storage that reduce the evils of gum formation, and the development of seasonal products such as gasoline designed to give the best results for summer in those sections of the country where the variations in the weather are notable.
The recovery of casinghead, or natural gasoline, has been an important scientific development, for it added to the supply of high grade motor fuel. It came with the development of efficient and economical means for recovering and stabilizing this light gasoline. Natural gasoline methods led to the separation of pro pane and butane, which were compressed and liquefied and made available in the form of gas in cylinders or steel bottles ("bottled gas") used wherever it was found unprofitable to run gas mains or establish gas plants. In addition this liquefied gas fuel was used to enrich water gas, and to meet fluctuating loads. Its constant heat value and easy operation made it very convenient to handle, and assured a more uniform performance of power plants.
The processes for stripping hydrogen sulphide from refinery gases and natural gases were developed to a high point of effi ciency and economy. They permitted the recovery of the gas uti lized as a fuel where the quantity of sulphur is too small to be valuable, or as a source of elemental sulphur where economy dictated that procedure. The process purifies the gas, a partic ularly important procedure where polymerization is concerned, and, at the same time, supplies by-products frequently of definite value.
In all this work, notable and essential contributions from other fields have been made—among them, the design and construction of huge conversion and catalyst chambers to stand high tempera tures and pressures. The perfection of the modern tube still and fractionating tower, to replace the old shell still equipped with air condensers, should be referred to. The important contribution of those long experienced in design, erection, and operation of dis tillation equipment, heat exchangers, control and recording de vices, and the multitude of items which make up the impressive equipment of the modern oil refinery, all have a part in this modern program. The development of treating processes using fuller's earth as the contact catalyst has served to increase the yield and quality of cracked gasoline, as well as lubricating oils, without contributing to the cost of production.