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C. GENERAL VIEW OF PLANT FOR CONDENSING GASOLINE BY REFRIGERATION. FROM LEFT TO RIGHT ARE SHOWN THE WATER TOWER, GAS RECEIVER, REFRIGERATING COILS, AND STILLS.
At Hastings, Warren County, Pa., and in the surrounding region the average quantity of gas per well increases over that in the other regions operated in the northern Pennsylvania fields. The quantity of gasoline obtained per 1,000 cubic feet of gas under conditions similar to those in the northern fields is approximately the same.
The oil fields extend south into Butler, Allegheny, and Washington Counties, and many successful plants are in operation in all those counties, although most of them are small. The wells utilized for gasoline production constitute a small proportion of the total number of oil wells, being less than 1 per cent.
As the oil fields extend into West Virginia and Ohio, especially those along the Ohio River on both sides from Steubenville to Marietta, Ohio, more wells are utilized-probably between 25 and 50 per cent of the total number of wells.
In this region are situated some of the largest and best equipped plants in the United States. The gas is as a rule rich in the gasolinemaking constituents, approximating on the average close to 3 gallons of 90° to 95° B. gasoline per 1,000 cubic feet of gas treated. Compression at 200 pounds pressure per square inch is employed.
COST OF GASOLINE-PLANT EQUIPMENT.
Compression and condensing equipment that will handle 120,000 cubic feet of gas per 24 hours costs about $2,800. This includes a 15-horsepower gas engine and low-stage compressor for a discharge pressure of 50 pounds per square inch, a 15-horsepower gas engine and high-stage compressor with a discharge pressure of 250 pounds per square inch, intercooler, aftercooler, accumulator tank, expansion coils, and refrigerating coil, and a lighting-plant equipment consisting of a 5-horsepower engine, generator, safety lamps, incandescent lamps, wiring, etc. The gas engines and the compressors are direct connected. The price of equipment varies from $2,800 for equipment for handling the smaller quantities of gas up to $7,800 for equipment capable of handling 600,000 to 700,000 cubic feet of gas. Foundations and housing for machinery, pipe lines to wells, railroad sidings, storage tanks, etc., are extra.
The authors are aware of one small plant from which the owner claims he derives a net income of $150 per month with a small equipment which handles only 60,000 cubic feet of gas in 24 hours. Conditions are such that this man is enabled to attend to this plant in addition to his regular duties. The gas used is exceedingly rich in gasoline vapors.
The authors have knowledge of two plants that cost $40,000 for complete installation, including the cost of compressors, two of them of 50 horsepower, two of 40 horsepower, two of 35 horsepower, and two of 20 horsepower, storage tanks, railroad sidings, and buildings
at the sidings, pipe lines to about 120 wells, foundation and housing for equipment, etc. The operating expenses for one year were $11,000. The cost for the salaries of six men included in the operating expenses was $7,000. The other $4,000 was paid for repairing the plant and for waste, oil, etc. The two plants sold 490,000 gallons of gasoline in 1913. For most of the gasoline the company received 13 cents per gallon. Probably 114 cents would be an average price; hence the gross income was 11 multiplied by 490,000, or $55,125, the net income therefore being $55,125 less $11,000, or $44,125. The company running these plants, by an unusual agreement, paid to a party from whom they bought the plant a royalty per year of 50 per cent of the profits, hence the owners' net gain was $22,062. Therefore, on the original investment, they realized about 55 per cent return for the year 1913.
PERCENTAGE OF VAPOR CONDENSED BY COMPRESSION AND COOLING.
The change in the raw gas that takes place in the compressors and coolers of a plant consists in the conversion of certain vapors and gases into liquid condition, and the solution of gases in these liquids. To give exact figures for the proportions of gas and vapor that disappear is impossible. An approximation can be reached, however. One gallon of liquid pentane when converted into gas produces about 31 cubic feet of gas at 0° C. and 760 mm. pressure. One gallon of propane in the liquid condition produces about 45 cubic feet of gas. One gallon of butane produces 37 cubic feet of gas. Butane and pentane are probably the two paraffins that are removed in greatest quantity.
Aside from such liquefaction a certain amount of gas is absorbed by the liquid, as stated above. It is small as regards the total disappearance of gas. The authors estimate that at some plants about 35 cubic feet of gas disappears for each gallon of condensate produced from 1,000 cubic feet of gas. If 4 gallons of condensate per 1,000 cubic feet of gas is obtained, then 140 cubic feet, or about 14 per cent of the gas treated, has disappeared. At some plants, however, as much as 50 per cent of gas disappears, and at others the quantity of residual gas is almost insignificant.
RESULTS OF ANALYSES OF GASES FROM DIFFERENT STAGES OF PLANT OPERATION.
Table 5 following shows the results of laboratory tests of various gases derived from the different stages of plant operation. The percentage of air was calculated from the oxygen content as determined by analysis.