PETROLEUM. Products of the Distillation of Crude Petroleum. Crude American petroleum of sp. gr. 0.800 may be split up by fractional distillation as follows (Robinson's Gas and Petroleum Engines): Lima Petroleum, produced at Lima, Ohio, is of a dark green color, very fluid, and marks 48° Baumé at 15° C. (sp. gr., 0.792). The distillation in fifty parts, each part representing 2% by volume, gave the following results: cent. 10 12 16 Gr. 0.680 Per Sp. Per Sp. Per Sp. Per Sp. Per Sp. cent. Gr. cent. Gr. 50 0.802 68 0.820 768 52 } .694 26 .740 42 .782 60 .698 28 .742 44 .788 62 14 .700 30 .746 46 .792 64 Residuum RETURNS. burning oil. 6 per cent paraffine oil. 10 46 residuum. 16 per cent naphtha, 70° Baumé. 68 66 The distillation started at 23° C., this being due to the large amount of naphtha present, and when 60% was reached, at a temperature of 310° C., the hydrocarbons remaining in the retort were dissociated, then gases escaped, lighter distillates were obtained, and, as usual in such cases, the temperature decreased from 310° C. down gradually to 200° C., until 75% of oil was obtained, and from this point the temperature remained constant until the end of the distillation. Therefore these hydrocarbons in statu moriendi absorbed much heat. (Jour. Am. Chem. Soc.) Value of Petroleum as Fuel.-Thos. Urquhart, of Russia (Proc. Inst. M. E., Jan. 1889), gives the following table of the theoretical evapora tive power of petroleum in comparison with that of coal, as determined by Messrs. Favre & Silbermann: In experiments on Russian railways with petroleum as fuel Mr. Urquhart obtained an actual efficiency equal to 82% of the theoretical heating-value. The petroleum is fed to the furnace by means of a spray-injector driven by steam. An induced current of air is carried in around the injector-nozzle, and additional air is supplied at the bottom of the furnace. Oil vs. Coal as Fuel. (Iron Age, Nov. 2, 1893.)-Test by the Twin City Rapid Transit Company of Minneapolis and St. Paul. This test showed that with the ordinary Lima oil weighing & 6/10 pounds per gallon, and costing 24 cents per gallon, and coal that gave an evaporation of 71⁄2 lbs. of water per pound of coal, the two fuels were equally economical when the price of coal was $3.85 per ton of 2000 lbs. With the same coal at $2.00 per ton, the coal was 37% more economical, and with the coal at $4.85 per ton, the coal was 20% more expensive than the oil. These results include the difference in the cost of handling the coal, ashes, and oil. In 1892 there were reported to the Engineers' Club of Philadelphia some comparative figures, from tests undertaken to ascertain the relative value of coal, petroleum, and gas. Lbs. Water, from and at 212° F. 1 lb. anthracite coal evaporated... 1 lb. bituminous coal. 1 lb. fuel oil, 36° gravity. 9.70 10.14 16.48 1 cubic foot gas, 20 C. 1.28 The gas used was that obtained in the destillation of petroleum, having about the same fuel-value as natural or coal-gas of equal candle-power. Taking the efficiency of bituminous coal as a basis, the calorific energy of petroleum is more than 60% greater than that of coal; whereas, theoretically, petroleum exceeds coal only about 45%-the one containing 14,500 heat-units. and the other 21,000. Crude Petroleum vs. Indiana Block Coal for Steamraising at the South Chicago Steel Works. (E. C. Potter, Trans. A. I. M. E., xvii, 207.)-With coal, 14 tubular boilers 16 ft. X 5 ft. required 25 men to operate them; with fuel oil, 6 men were required, a saving of 19 men at $2 per day, or $38 per day. For one week's work 2731 barrels of oil were used, against 848 tons of coal required for the same work, showing 3.22 barrels of oil to be equivalent to 1 ton of coal. With oil at 60 cents per barrel and coal at $2.15 per ton, the relative cost of oil to coal is as $1.93 to $2.15. No evaporation tests were made. Petroleum as a Metallurgical Fuel.-C. E. Felton (Trans. A. I. M. E., xvii, 809) reports a series of trials with oil as fuel in steel-heating and open-hearth steel-furnaces, and in raising steam, with results as follows: 1. In a run of six weeks the consumption of oil, partly refined (the paraffine and some of the naphtha being removed), in heating 14-inch ingots in Siemens furnaces was about 6% gallons per ton of blooms. 2. In melting in a 30-ton open-hearth furnace 48 gallons of oil were used per ton of ingots. 3. In a six weeks' trial with Lima oil from 47 to 54 gallons of oil were required per ton of ingots. 4. In a six months' trial with Siemens heating-furnaces the consumption of Lima oil was 6 gallons per ton of ingots. Under the most favorable circumstances, charging hot ingots and running full capacity. 4% to 5 gallons per ton were required. 5. In raising steam in two 100-H.P. tubular boilers, the feed-water being supplied at 160° F., the average evaporation was about 12 pounds of water per pound of oil, the best 12 hours' work being 16 pounds. In all of the trials the oil was vaporized in the Archer producer, an apparatus for mixing the oil and superheated steam, and heating the mixture to a high temperature. From 0.5 lb. to 0.75 lb. of pea-coal was used per gallon of oil in the producer itself. FUEL GAS. The following notes are extracted from a paper by W. J. Taylor on "The Energy of Fuel" (Trans. A. I. M. E., xviii. 205): Carbon Gas.-In the old Siemens producer, practically, all the heat of primary combustion-that is, the burning of solid carbon to carbon monoxide, or about 30% of the total carbon energy-was lost, as little or no steam was used in the producer, and nearly all the sensible heat of the gas was dissipated in its passage from the producer to the furnace, which was usually placed at a considerable distance. Modern practice has improved on this plan, by introducing steam with the air blown into the producer, and by utilizing the sensible heat of the gas in the combustion-furnace. It ought to be possible to oxidize one out of every four lbs. of carbon with oxygen derived from water-vapor. The thermic reactions in this operation are as follows: Heat-units. 4 lbs. C burned to CO (3 lbs. gasified with air and 1 lb. with water) develop.. 17,600 1.5 lbs. of water (which furnish 1.33 lbs. of oxygen to combine with 1 lb. of carbon) absorb by dissociation.. 10,333 The gas, consisting of 9.333 lbs. CO, 0.167 lb. H, and 13.39 lbs. N, heated 600°, absorbs. 3,748 Leaving for radiation and loss The steam which is blown into a producer with the air is almost all condensed into finely-divided water before entering the fuel, and consequently is considered as water in these calculations. The 1.5 lbs. of water liberates .167 lb. of hydrogen, which is delivered to the gas, and yields in combustion the same heat that it absorbs in the producer by dissociation. According to this calculation, therefore, 60% of the heat of primary combustion is theoretically recovered by the dissociation of steam, and, even if all the sensible heat of the gas be counted, with radiation and other minor items, as loss, yet the gas must carry 4 × 14,500 – (3748 +3519) = 50,733 heat-units, or 87% of the calorific energy of the carbon. This estimate shows a loss in conversion of 13%, without crediting the gas with its sensible heat, or charging it with the heat required for generating the necessary steam, or taking into account the loss due to oxidizing some of the carbon to CO,. In good producer-practice the proportion of CO, in the gas represents from 4% to 7% of the C burned to CO2, but the extra heat of this combustion should be largely recovered in the dissociation of more water-vapor, and therefore does not represent as much loss as it would indicate. As a conveyer of energy, this gas has the advantage of carrying 4.46 lbs. less nitrogen than would be present if the fourth pound of coal had been gasified with air; and in practical working the use of steam reduces the amount of clinkering in the producer. Anthracite Gas.-In anthracite coal there is a volatile combustible varying in quantity from 1.5% to over 7%. The amount of energy derived from the coal is shown in the following theoretical gasification made with coal of assumed composition: Carbon, 85%; vol. HC, 5%; ash, 10%; 80 lbs. carbon assumed to be burned to CO; 5 lbs. carbon burned to CO,; three fourths of the necessary oxygen derived from air, and one fourth from water. Energy in the above gas obtained from 100 lbs. anthracite: 186.66 lbs. CO. CHA Total energy in gas per lb.. 807,304 heat-units. "100 lbs. of coal..1,349,500 Efficiency of the conversion The sum of CO and H exceeds the results obtained in practice. The sensible heat of the gas will probably account for this discrepancy, and, therefore, it is safe to assume the possibility of delivering at least 82% of the energy of the anthracite. Bituminous Gas.-A theoretical gasification of 100 lbs. of coal, containing 55% of carbon and 32% of volatile combustible (which is above the average of Pittsburgh coal), is made in the following table. It is assumed that 50 lbs. of C are burned to CO and 5 lbs. to CO; one fourth of the O is derived from steam and three fourths from air; the heat value of the volatile combustible is taken at 20,000 heat-units to the pound. In computing volumetric proportions all the volatile hydrocarbons, fixed as well as conden sing, are classed as marsh-gas, since it is only by some such tentative assumption that even an approximate idea of the volumetric composition can be formed. The energy, however, is calculated from weight: Water-gas.-Water-gas is made in an intermittent process, by blowing up the fuel-bed of the producer to a high state of incandescence (and in some cases utilizing the resulting gas, which is a lean producer-gas), then shutting off the air and forcing steam through the fuel, which dissociates the water into its elements of oxygen and hydrogen, the former combining with the carbon of the coal, and the latter being liberated. This gas can never play a very important part in the industrial field, owing to the large loss of energy entailed in its production, yet there are places and special purposes where it is desirable, even at a great excess in cost per unit of heat over producer-gas; for instance, in small high-temperature furnaces, where much regeneration is impracticable, or where the "blow-up" gas can be used for other purposes instead of being wasted. The reactions and energy required in the production of 1000 feet of watergas, composed, theoretically, of equal volumes of CO and H, are as follows: 500 cubic feet of H weigh.. 500 cubic feet of CO weigh.. Total weight of 1000 cubic feet..... 2.635 lbs. 36.89 66 39.525 lbs. Now, as CO is composed of 12 parts C to 16 of O, the weight of C in 36.89 lbs. is 15.81 lbs. and of O 21.08 lbs. When this oxygen is derived from water it liberates, as above, 2.635 lbs. of hydrogen. The heat developed and absorbed in these reactions (roughly, as we will not take into account the energy required to elevate the coal from the temperature of the atmosphere to say 1800°) is as follows: Heat-units. 2.635 lbs. H absorb in dissociation from water 2.635 × 62,000.. 163,370 15.81 lbs. C burned to CO develops 15.81 X 4400... Excess of heat-absorption over heat-development = 69,564 = 93,806 If this excess could be made up from C burnt to CO2 without loss by radiation, we would only have to burn an additional 4.83 lbs. C to supply this heat, and we could then make 1000 feet of water-gas from 20.64 lbs. of carbon (equal 24 lbs. of 85% coal). This would be the perfection of gas-making. as the gas would contain really the same energy as the coal; but instead, we require in practice more than double this amount of coal, and do not deliver more than 50% of the energy of the fuel in the gas, because the supporting heat is obtained in an indirect way and with imperfect combustion. Besides this, it is not often that the sum of the CO and H exceed 90%, the balance being CO2 and N. But water-gas should be made with much less loss of energy by burning the "blow-up" (producer) gas in brick regenerators, the stored-up heat of which can be returned to the producer by the air used in blowing-up. The following table shows what may be considered average volumetric analyses, and the weight and energy of 1000 cubic feet, of the four types of gases used for heating and illuminating purposes: ton of coal. Approximately 30,000 cubic feet of gas have the heating power of one Calculated upon this basis, the 131,280 ft. of gas from the ton of coal contained 20,311,162 B.T.U., or 155 B.T.U. per cubic ft., or 2270 B.T.U. per lb. The composition of the coal from which this gas was made was as follows: Water, 1.26%; volatile matter, 36.22%; fixed carbon, 57.98%; sulphur, 0.70%; ash, 3.78%. One ton contains 1159.6 lbs. carbon and 724.4 lbs. volatile combustible, the energy of which is 31,302,200 B.T.U. Hence, in the processes of gasification and purification there was a loss of 35.2% of the energy of the coal. The composition of the hydrocarbons in a soft coal is uncertain and quite complex; but the ultimate analysis of the average coal shows that it approaches quite nearly to the composition of CH, (marsh-gas). Mr. Blauvelt emphasizes the following points as highly important in softcoal producer-practice: |