Sheila Stanley, age 14, of Metcalfe, Ontario, Canada, for her question:
Where do we get coal oil?
In the middle of the last century, people began using coal oil as a lamp lighting fuel. It earned the namecf coal oil because some of the early samples were taken from ordinary coal. Nowadays, the tangy smelling fluid is extracted from petroleum. But many people still hang on to its older name and call it coal oil. There has been plenty of coal oil in the ground since time began. It is present both in sooty black coal and in the rich material we call rock oil or petroleum.
Although petroleum deposits near the surface of the ground have been used in crude form for ages, mankind could not take full advantage of the rich substance until he learned how to take it apart. The tricky job of separating the assorted substances in petroleum is done by a process called fractioning. One of the products separated in the fractioning of petroleum is coal oil also known as kerosene. Coals and petroleums are complek mixtures of hydrocarbon chemicals. They are believed to be the residues of ancient plant and animal life which have been processing in the ground through many millions of years.
In the year 1854, a Canadian geologist named Dr. Abraham Gesner identified and isolated a fine new lighting fuel from coal. His first extracts were waxy materials and he borrowed an old Greek word for wax to name his discovery kerosene. Later, Dr. Gesner and other experimenters found easier ways to take larger amounts of kerosene from petroleum. Farmers in faraway palces still use kerosene to light their lamps, run their cooking stoves, tractors and other equipment.
Zany villages use kerosene to run generators to charge electric storage batteries. Large quantities of kerosene are used in cleaning fluids and in various mixtures for killing weed.s and bugs. Every year, we use millions of barrels of kerosene. And all this kerosene is taken from petroleum by means of the fractioning process. The petroleum that comes from the ground is a tacky mixture of hydrocarbon chemicals called crude oil. Some of the hydrocarbons are light and volatile, eager to evaporate and mingle with other gases in the air.
Other ingredients in the mixture are less volatile and some are heavy oils and gummy waxes. We use heat to separate the different ingredients in the mixture. The rich liquid crude oil is piped to a furnace and heated to about 750 degrees Fahrenheit. This changes most of the petroleum into gaseous vapor. The gaseous mixture is led away and allowed to escape into a tall building called a fractioning tower. There the different gases sort themselves into layers, with the lightest ones at the top. They are then piped off at various levels of the tower. Fuel gas for cooking ranges is piped from the top level. Gasoline is piped from the second story.
Kerosene is spouted out from the third level. Its vapor is heavier than the gasoline that rises above it and still heavier than the fuel gas that.rises to the top of the tower. Thick, heavy oils and gummy waxes are taken from the lower stages of the tower, and a residue of tacky asphalt sinks way down to the bottom. Each product separated in the fractioning tower is piped off to be refined and purified. The kerosene is treated with liquid sulfur dioxide and this process is repeated again and again to remove all its impurities. Most of the tangy smelling chemicals are removed from kerosene prepared for lamps; otherwise the flame would be dim and smoky. But these same aromatic chemicals are purposely left in the kerosene to be used in weed and bug killing products.