Jillv. 1923
I N D U S T R I A L A N D ENGINEERING CHEMISTRY
689
Light Oil in Coke-Oven Gas‘ Use of Activated Carbon in Its Determination By Arthur L. Davis STANDARD OIL COMPANY (INDIANA), WOODRIVER, ILL.
HE quantity of the light oil in coke-oven gas, before and after scrubbing with straw oil, is generally determined by passing a definite quantity of the gas through straw oil contained in a train of bottles packed in ice, and subsequently separating the light oil from the straw oil by distillation. The removal of the light oil from the gas approaches completeness only when the flow of gas is extremely slow, and under all conditions the method of procedure is cumbersome. The light oil present in the gas may be determined readily and accurately by the absorption of the condensable vapor in a definite quantity of gas by activated carbon, with subsequent removal by distillation of the carbon with U. s. P. cresol. Carbon of activity 40 to 50, screened 8 to 14 mesh, is suitable. APPARATUS The absorption requires a 0.1-cu. ft. gas meter and two activated carbon tubes complete. The carbon tubes are cylindrical containers, 1.5 in. in diameter and 12 in. in length over all, fitted with a 20-mesh screen in one end, with 1-in. breasts and screw caps on both ends. Four connecting caps consisting of 1-in. screw caps carrying 5/16 x 3/4-in. copper tubes soldered in the centers and fitted with l/16-in. rubber gaskkts are used on each carbon tube during the absorption proper. The distillation of the enriched activated carbon with cresol to remove the light oil is made using a 500-cc., round-bottom, side-neck, Pyrex distilling flask; a 4-in. ring burner; a 200’ C. thermometer; a “Barrett standard” condenser; a 200-cc. separatory funnel graduated to 100 cc.; U. S. P. cresol; and sodium hydroxide solution of specific gravity 1.10 to 1.15.
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PROCEDURE ABSOEPTION-Place 300 cc. of activated carbon in each of the two carbon tubes. Screw a connecting cap with rubber gasket to each end of each tube, and tighten with a pair of combination pliers. Connect the inlet of the wet gas meter to the gas sampling tube and allow gas to pass through for several minutes to insure a thorough displacement of air. Turn off the gas, set the indicating hands of the meter to the zero position. (Caution: See that the hands are reasonably loose before turning so that the driving shafts will not be twisted.) Connect the top of the first carbon tube t o the outlet of the gas meter, the bottom of t h e first tube to the bottom of the second tube, and either allow t h e residual gas coming from the top of the second tube to escape or be conducted away by an attached exit tube. Keep the tubes in a vertical position. Pass an amount of gas containing approximately 30 to 40 cc. of light oil through the absorption tubes, a t the rate of 10 t o 15 cu. ft. per hr. At the completion of the absorption note t h e volume of gas passed, the temperature of the gas, and the barometric pressure. DISTILLATION-P1ace the enriched carbon from the first tube in a ~OO-CC.,side-neck, Pyrex distilling flask, add 125 cc. of cresol, nzix thoroughly by shaking in the flask, insert the thermometer in neck of the flask, and connect to a “Barrett stand1
Received August 12, 1922
ard” condenser. Heat carefully with the ring burner and distil a t a moderate rate till the temperature of 180” C. is reached. Collect the distillate in the 200-cc. separatory funnel, which is graduated to 100 cc. Add 125 cc. of sodium hydroxide solution, specific gravity 1.10 to 1.15 (8 to 13 per cent), and agitate thoroughly. Care should be taken to release the pressure of the gas which is often built up. Allow to stand for a few minutes, run off the sodium hydroxide solution, and record the volume of light oil obtained. Repeat the foregoing procedure with the second carbon tube. Record the volume of light oil obtained separately. The sum of the two volumes of light oil‘obtained above gives the total volume of light oil from the volume of gas passed at the temperature and barometric pressure recorded. CALCULATION-The amount of light oil present in the gas (volume corrected to 15.5” C. (760 mm.)) is calculated as follows : Total volume of light oil X 0.264 = Gal. light oiI per 1000 cu. ft. gas 288.5 Bar. press. cu’ gas 273 temp. O C. 760 Gal. light oil per 1000 cu. f t . X 12 = Gal. light oil per ton of coal (One ton of coal produces approximately 12,000 cu. f t . of gas)
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VOLUME OF GASREQUIRED I n order that the time required for making an absorption may be fairly accurately determined before making a test, the volume of gas containing a certain amount of condensable vapor should be known. The volume of gas containing approximately 30 to 40 cc. of light oil is shown in the table. OF COKE-OVEN VOLUME GASREQUIRED FOR CHARCOAL ABSORPTIONMETHOD Gal. Light Oil Cu. Ft. Gas per Ton Coal Required for (12,000Cu. Ft.) Determination 0.5 190-250 1.0 96-125 1.5 63-83 2.0 47-60 2.5 38-50 3.0 31-41 3.5 27-36 4.0 24-31 4.5 21-28
I n making routine analysis by this method it is advised that the determination of the gas entering the scrubbers and the gas leaving the scrubbers be made simultaneously. The spent activated carbon containing cresol may be revivified, but it is more satisfactory t o use fresh material for each determination.
Fall Meeting of a m e r i c a n Electrochemical Society The next meeting of the American Electrochemical Society is t o be held in Dayton, Ohio, September 27, 28, and 29, 1923. The meeting will include a symposium on electrochemistry of gaseous conduction, in charge of Duncan MacRae, Research Laboratory, Westinghouse Lamp Co., Bloomfield, N. J., and a symposium on recent progress in electrolytic refining, under the chairmanship of F. R. Pyne, U. S. Metals Refining Co., Carteret, N. J. An innovation at the meeting will consist of round-table discussions on electric-furnace brass-foundry practice, organic electrochemistry, chlorine, and electroplating. There will also be excursions to local plants.
