INDUSTRIAL AND E.VGIA\rEERISG CHEAMISTRY
October, 1929
precision calorinietric methods. These values are also in agreement w-it'hresults of other experimenters and check fairly closely with those obtained from the average formula derived from all the formulas found in the literature. The lower the A. 1'. I. gravity of the fuel oil or residuum, and consequently the cheaper the oil, th6 loner will be the B. t. 11. value per pound hut the higher the B. t . u. value per gallon. The latter unit is the usual one hg which such fLielsare purchased. 4-Comhustion analyses show that a normal residuum has a lower carlmi and higher hydrogen content than a flashed residuum. The average ratio of carbon to hydrogen is 8.66 for the norinal residuum and 9.22 for the flashed residuum. I3oth the normal and flashed residuums have higher carbon and lower hydrogen contents than the straight-run fuel oils. The ratio of carbon to hydrogen in the latter is 7.08. 5-The calorific value per pound of oil calculated by substituting the percentages of carbon, hydrogen, oxygen, and sulfur in the Dulong formula gives values about 1077 B. t. u. per pound greater than the experimentally determined d u e for the straight-run fuel oils and about 740 B. t. u. per pound greater for the two types of residuum. 6-The net calorific value was calculated for several straightrun fuel oils and the two residuums produced from them. These values are about 1200 B.t. u. per pound less than the observed or gross calorific values as the result of the correction for the latent heat of vaporization of water. 7-The data do not show any definite relationship between the B. t,. u. values per pound of oils of the same gravity and the source of the oils. 8-There is no apparent relation bet'ween the coke formation by Engler distillation and the B. t. u. value per pound. An oil that produces a high percentage of coke may h a r e as high a B. t. u. value as one that' produces little coke. 9-The volatility of the cracked residuums is slightly greater than that of t8hestraight-run fuel oil, but in no case ia there enough material within the boiling range of gasoline to cause any marked variation in the B.t . u. value of the fuel on t'lie basis of a pound or a gallon. 10-A comparison of the characteristics of the flashed and normal residuums shows that the former possess a higher cold test and a higher viscosity than the normal residuums. The B. t . 11. value per pound for t,he flashed residuum for the six
94 1
samples examined indicates about 10 per cent less 13. t. 1 1 . per pound for similar gravities, although Plot KO.3 does Il(Jt show any regularity in this regard since the B.t. 11. values of the lorn-pressure (flashed) residuum fall ahore or below the average curve just as much as those of the iiormal residuum. 11-The R. S. content does not have any material effect upon the filial B. t . u . value per pound. The B. S. material shows a loner B. t. u. value per pound than the oil which held it; one per cent of B. S.as determined by the benzene-centrifuge method reduces the calorific value by 10 B. t. u. per pound. The B. t. u. value per pound of a residuum containing 2 per cent of R. S. (Bunker "C" Specification) ~vouldbe approximately 20 B. t. u. per pound low, which is less t,han the allowable experimental error in calorimetric determinations. 12-The B. S.material separated from a flashed or a normal residuum contains organic matter which is soluble in organic solvents such as chloroform, carbon tetrachloride, carbon disulfide, aniline! etc., to the extent of 40 to 45 per cent. T h e dissolved matter has the same carbon-hydrogen rat,io as the residuum itself. There is present', however, about 55 per cent of insoluble material containing about eighteen times as much carbon as hydrogen. The ash content is high arid the sulfur content is fairly high. According to classifications in existence for such substances, the B. S. material shows a composition corresponding to 1.3 per cent of petrolenes; 98.7 per cent of asphaltenes (contaminated with inorganic matter), 10.0 per cent of carbenes, 33.8 per cent of carbon tetrachloride inuoluble asphaltenes, 42.6 per cent of carbonaceous inaterial insoluble in carbon disulfide and combustible in oxygen a t 700" C. (1292" F.)!and 12.3 per cent, insoluble aiid noncombustible matter. Literature Cited (1) 4.S. T.hf.Standard Method for Thermal Value of Fuel Oils, D-240-27, ( 2 ) Cross, Kansas City Testing Laboratory, Bull. 25. ( 3 ) Dice, C/ie!n. .Wet. Eng.. 26, 499 (1922). (4) Fenn, Engineering s, M a y 13, 1939; also Kent's Handbook, p. 886
(1928). (5) (6) (7) (8)
Fisher, Laboratory RIanual of Organic Chemistry, Pt. 11, 11. 217 (1924). Haslam and Russell, ''Fuels and Their Combustion,'' p. 113. LeConte, Heine Boiler Co., "Helios," p. 4 i 9 . Morpurgo, J f i l t . stoatl. l e c h . I~crsuchsomies(TVien), 10, 97 (1912). (9) Sherman and Kropff, J . . l m . C h e m . Soc., 30, 1626 (1908).
Deposition of Carbon in Reaction between Carbon Dioxide and Hydrogen' Merle Randall a n d W. H. Shiffler D Cohrp,\xY, RICHMOND. CALIF USIVZRSITY OF CALIFORSI.I, BBRKEI.ET.CALIF.,A N D S T A N D A ROIL
I
X COXNECTION with the discussion of the depositio.1 of carbon in the reaction 2H2O !g) CO? ( g ) -1Hz fg) = CH, recently given by Randall and Gerard (I), there is another reaction not mentioned-namely, CO, (gj -t 2H2 (g) = C (graph) 2H2O (gJ (14) This reaction is the slim of Reactions 12 and 13 of their paper and can largely explain the experimental restilts. I n Table I, column 1 gives the number of the experiment, column 2 gives the mols per minute of unaccounted-for carbon from Table I V of their article, and column 3 the value of A F I T for the new reaction. The sign of A F / T explains the formation of carbon by direct union of carbon dioxide and hydrogen in five of the eight cases of appearance of carbon, and for the disappearance in fourteen out of the nineteen cases. It is also noted t h a t the sign of A F / T is correct for Equation 14 in every case in which the value of I in Equation ti was less than -39.1, equilibrium conditions in this reaction being represented by I = -39.91.
+
+
+
I
Received July 1 6 , 1929.
EXI'T. A- 1 A-2
-4.3 A-4 A-5 A-6
A-7 A-8 A-9 A-10 '4-11 A-12 A-13 A-14
Table I-CO! CARBON 0.0000104 0 0000120 0 0000067 0.0000145 0 0000021 0.0000076 0,0000023 O.OOO0146 -0.0000010 -0.0000052 - 0 0000038 -0 0000072 - 0 0000004 - 0 0000044
(g)
+
ZH! (g! lF/T - 1 4 44 -13.87 - 5.23 - 0.76
0 14 - 0.04
1.76 1 46 1.99 1,53 1 59 1 34 -4 64 -0 48
=
C (graph) 4 2Hr0 ig)
EXPT. A-15 A-16 A-17 -4.18 A-19 A-20 A-21 A-22 B-l B-2 B-3 B-4 B-5
CARBON -0.0000037 -0 0000076 - 0 0000018 -0 0000033 -0,0000026 -0.0000011 - 0.0000042 -0.0000051 - 0.0000009 -0.0000003 -0 000004'2 - 0 0000043 - 0 0000054
ll.'/Z' -0.63 -1 34 -0 2 5 0 90 1 8!l 1 79 1.43 1 37 1 60 1 46
2 20 1 33 1 72
While the formation of carbon by the direct reaction of carbon dioxide and hydrogen, in accordance with Equation 14, offers a possible explanation of the results, the mechanism of the rcaction may easily be a series of reactions.
Literature Cited (1) Randall and Gerard, IUD Ehc CHEM 20, 1335 (1928)
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