FUEL OIL The use of oil as fuel has been a remarkable de velopment of the past few years. After carefully in vestigating the source of supply, both the older oil fields that have long been producing as well as the newer fields, such as those in Mexico, together with the possibilities of finding oil in Central and South America, the navies of the world have decided to adopt oil as fuel for part of their fleet, at least. With the erection of large oil storage tanks throughout the important seaports of the world the steamship com panies also do not now hesitate to equip their steam ers for burning fuel oil.
The opening of the Panama Canal has changed the old established routes of many steamship lines and fuel oil from the California, Mexican and Central American fields can be obtained at an attractive fig ure at the Canal. Thus steamers operating from New York or European ports, through the Canal to Pacific or China ports, are now able to take advantage of the cheap fuel. The large oil storage tanks that have been erected through the country, insure to the industrial manufacturer also, a steady and regular supply of fuel oil.
These vast storage tanks, the many oil tank cars operated by the railroads, the numerous tank steamers carrying the oil to all parts of the world, and the new oil fields have eliminated any question as to an ade quate supply.
The use of fuel oil is now well established, and new uses are being discovered daily. The question of cheap transportation of this valuable product has been solved by the large tank steamers, some of which carry over 120,000 bbl. of oil. When the authorities decide the rate question of transporting oil by tank cars and pipe lines, a still lower price will probably prevail.
Some crude oils are suitable for fuel in their natural state, for others lighter gases must be distilled. Most of the fuel oil sold has been refined, being the residue from the crude petroleum after the more val uable ingredients have been taken out and much of the sulphur removed. The calorific value of the fuel oils from the different countries varies but little from 18,500 B.t.u.
In figuring the comparative value of fuel oil and coal the steam engineer usually compares the amount of water evaporated by unit weights of oil and coal ; the electrical engineer figures the kilowatt hours pro duced with each pound of fuel, while manufacturers are interested in the equivalent value of a barrel of oil, compared with a ton of coal, a cord of wood, or a thousand cubic feet of gas. On account of the wide ly different heating values of various fuels, it is diffi cult to prepare a table showing exactly the equivalent value of one barrel of oil. The following table affords a rough comparison between coal fuel under similar conditions of boiler loading.
It has been common practice to estimate four bar rels of oil equal to one ton of coal, but that this is not always the case is proved by the following test. Under a boiler one pound of coal evaporated 7 lb. of water from and at 212 degrees F., and one pound of oil evapo rated 15 lb. of water from and at 212 degrees F. The rates of evaporation per pound of fuel were in the ratio of 7 to 15 ; and as the coal weighed 2000 lb. pet ton and the oil 330 lb. per barrel, one ton of coal was equivalent to 2" X7 = 2.828 barrels of oil. On 330 X 15 the other hand, a good grade of coal may have 14,500 B.t.u. per pound, while oil averages 18,500 B.t.u. per pound. The theoretical equivalent of one ton of coal 2000X 14500 in this case is 330X 18500 = 4.75 barrels of oil.
These cases may seem extreme, but they indicate the danger of using "rules of thumb" in making prelimi nary calculations of fuel consumption. The writer has seen many cases in which a contractor has failed to meet his specifications, simply because he took it for granted that four barrels of oil were the equiva lent of one ton of coal.
It is equally difficult to compare the heating value of a cord of wood with that of a barrel of oil. The heating value of the wood in question must be known, as well as the percentage of water that it con tains, before making a comparison with oil fuel.