INDUSTRIAL BiYD EA’GINEERILVG CHEMISTRY
October, 1929
Acknowledgment
933
Literature Cited
The writers wish to acknowledge their grateful indebtedness to Gerhart Rosenbaum, formerly of Puchow and Vahon, Czechoslovakia, and now Of Split-Vranizza; to Professor Bailey and l l r . Griffin, of the Geology Department of the Cniversity of Illinois, who graciously furnished many of the specimens on whicl, this investigation is based; and to 8. L. Van Orden for assistance in some of the experimental work.
(1) Bateman,
con. Geol., IS, 663
(1923).
$ ::::Sqfiatt;; ~ e ~ ~ ~ ~ ~ ~ ) : , i n e r a l 3rd ogy ed,, ,”
p, 573, (4) Graham, Econ. Geol., 12, 154 (1917); Trans. A m . Inst. M i n . A f c i . Enn.. ’
67, 91 (1917). ( 5 ) I f a r k , 2. K ~ i 5 t . 61, , 7 5 (1925). ( 8 ) Svedberg, “Colloid Chemistry,” p. 129, Chemical Catalog Co. ( 7 ) Taber, Trans. A m . Inst. J l i n . M e t . Eng., 67, 62 (1917). ( 8 ) Taber, pvoc, x-tl. A c a d , sei,, 3, 299 (1917), (9) Warren and Bragg, 2. Krist., 69, 168 (1928).
Relationship between Calorific Value and Other Characteristics of Residual Fuel Oils and Cracked Residuums’ W. F. Faragher, J. C. Morrell, and J. L. Essex UNIVERSAL OIL PRODUCTS COMPANY, CHICAGO, ILL
The authors find that the relationship between caloFenn ( 4 ) relates the gravity rific value in B. t. u. per pound and A. P. I. gravity and calorific value in B. t. u. quantitative relationof cracked residuums is linear. They confirm also the per pound for California fuel ship between the calolinear relationship for uncracked Iuel oils that have oils as follows: rific value and the A. P. I. been reported by several other investigators. New gravity of fuel oils such as Calorific value = 17,780 formulas for calculating the calorific value per pound topped crude oil and cracked [SO X degrees Baume] of dry oil were determined as follows: 17,01QK90 X r e s i d u u m would be useful. O A. P. I.) for the straight-run fuel oils and 17,64%54 X The curve plotted from this Practically ail the data pub‘A. P. I.) for the cracked residuums. The calorific value formula practically parallels lished in the literature deal per gallon may be obtained by multiplying each of that plotted from the LeConte with the straight-run fuel oils these equations by the weight of a gallon of the fuel formula. of ordinary distillation; hence oil. These formulas are based upon bomb determinaCross ( 2 ) shows a series of it is desirable to learn how tions of the calorific value of a large variety of fuel curves and extrapolated data residuum from cracking stills oi!s and cracked residuums. The source of the oil, the for the relationship between isrelated to them. Theeffect E. S. material, the volatility, etc., do not appear to gravity and calorific value in upon the calorific value of all affect the calorific value so long as the A. P. I. gravity B. t. 11. per pound and per the variable factors, such as is not altered. Some information was obtained on gallon. According to him, m o i s t u r e , s u l f u r , B . S. the composition of the B. S. material present in cracked (Bunker “C” Specification), the curves plotted embody residuums. carbon and hydrogen ratio, thousands of analyses of fuel as well as the source of the oils from hundreds of sources: fuel oil, has been clearly established. hence the curves should represent average data for residual From time to time formulas for calculating the calorific fuel oils. It is said that all the analyses are on the dry basis. value of an oil when the gravity alone is known have been The formula developed from these data is as follows: published. Several of them have been assembled for critical Calorific value = 18,285 [41 X degrees Baume] review. Dice (3) has summarized briefly bhe various formulas pubThe data given by Haslam and Russell (6) are substantially lished in the literature. LeConte ( 7 ) gives the following the same as those given by Cross; the formula calculated from formula for the calculation of the approximate calorific value: the curves corresponds closely with the Cross curve. Sherman and Kropff (9) give about the same formulas as Calorific value = 17,680 [60 X degrees Baumi.] Dice gives for Xorth Texas Oils, i. e.: No mention is made of the kind of oil used or of the number Calorific value = 18,650 [40 X (degrees Baume - l o ) ] of oils analyzed. Dice says that a certain large company operating in Texas uses the following formula for calculating It will be seen from the above formulas that there is a the calorific value of Korth Texas oils: straight-line relationship between the gravity and the calorific value in 13. t. u. per pound of oil. I n general refinery practice Calorific value = 18,500 [40 X (degrees Baume - l o ) ] the Baumb scale has been discarded and the A. P.I. scale has He says also that the calorific value of California fuel oils been substituted. For the range of 10” to 35” A. P. I. (which changes about 40 B. t. u. per degree Baumi.; this value gives includes most fuel oils) there is a maximum difference of the formula: 0.3 degree between the two scales. This difference in gravity corresponds to about 30 B. t. u.per pound a t the higher graviCalorific value = 18,165 [40 X degrees Baume] ties and t o a negligible value at the lower gravities. Received April 24, 1929. Presented under the title “Relationship I n Plot Xo. 1 these formulas have been expressed in the between Fuel Value, A. P. I. Gravity, and Composition of Uncracked and form of curves. All the curves have about the same slope, Cracked Fuel Oils” before the Division of Petroleum Chemistry a t the with a maximum difference between them of 500 B. t. u. a t the 76th Meeting of the American Chemical Society, Swampscott, Mass., September 10 to 14, 1928. low A. P.I. gravities and 200 B. t. u. a t the high gravities.
A
h’ A C C U R A T E L Y
+
+
+
+
+
+
Vol. 21, No. 10
INDUSTRIAL AND ENGINEERING CHEMISTRY
934
Experimental Work on Commercial Fuel Oils
The following types of fuel oil were used in the determinations reported in this paper: (1) topped crude oil or cracking stock, (2) normal cracked residuum (made at high pressures), and (3) flashed cracked residuum (made a t low pressures). The two residuums are produced under different conditions of operat,ion. The normal residuum represents the heavy fuel oil drawn from the reaction chamber of a Dubbs cracking still maintained a t the same pressure as the last tube of the heating coil. The flashed residuum is produced by quickly
removing the residuum from the reaction chamber and reducing the pressure on it to atmospheric or a slightly higher pressure. The light products distil rapidly from the heavy residual oil. I n this operation the time of reaction for the residuum is reduced materially; this provision offers the advantage that little cokelike material is formed and a p r o l o n g e d operating cycle is realized. The gasoline yield is lowered slightly during the flashing operation, but t h i s l o w e r yield is offset by a higher yield of marketable residuum and a considerably lower yield of coke and uncondensable pas. The topped cride oils, together with all the fuel-oil cracking stocks which were available, were analyzed for water, sulfur, light-oil content, and B. S.; the calorific value was determined by the oxygen-bomb calorimeter ( I ) , a procedure which entails an allowable error in check determinations of 0.3 per cent or approximately 60 B. t. u. per pound. The calorific values expressed in B. t. u. per pound for the dry oil are shown in Table I ; they have been plotted against the gravity in degrees A. P. I., and the average curve has been drawn through the points. This curve is shown on Plot No. 2.
Table I-Straight-Run
TYPEOF
CRUDE
ENGLER DISTILLATION
SP. GR. A. P. I. 6Oo/6O0F. WEIOA'
GRAVITY (15.6'/
Deg. Midcontinent 9.5 Ebano, Mexico 13.8 14.2 Venezuela, S. A. Mene Grande, S. A. 1 4 . 8 15.2 Venezuela, S. A. Trinidad, B. W. I. 1 5 . 4 Irma, Ark. 15.7 15.8 Men; Grande, S. A. 1 6 . 1 Trinidad, B. W. I. 16.7 California 17.1 Seminole, Okla. 17.2 17.9 CaiIfornia 18.6 Ventura, Calif. 18.7 Eldorado, Ark. 18.8 Texas 19.2 W. Texas 19.9 California 20.1 Mixed Illinois and Mexican fluxes 2 0 . 1 20.1 Comodoro, S. A. Seminole, Okla. 20.6 McCamey, Texas 21.1 22.1 Comodoro, S. A. 22.3 Comodoro, S. A. Panhandle, Texas 22.5 Oklahoma 22.7 California 23.3 Texas 23.9 Kentucky 24.2 Grosny, Russia 24.2 Kentucky 24.4 Mixed Kansas 25.1 Midcontinent 25.3 Midcontinent 25.3 Mixed Archer and Wichita Co. 25.5 Potwin, Elbing, and Peabody 25.5 Kentucky 25.5 Oklahoma 25.9 Midcontinent 26.1 Italian 26.1 California 26.2 Midcontinent 26.7 Ventura, Calif. 29.4 Pennsylvania 35.1 Midcontinent 39.0
1.0030 0.9738 0.9712 0,9672 0.9647 0.9630 0.9610 0.9604 0,9587 0.9548 0.9522 0.9516 0.9471 0,9427 0.9421 0,9415 0,9390 0.9346 0,9334
Lbs./gal 8.35 8.11 8.09 8.06 8.03 8.02 8.01 8.00 7.98 7.95 7.93 7.92 7.89 7.85 7.85 7.84 7.82 7.78 7.77
0,9334 0.9334 0.9303 0.9273 0,9212 0.9200 0.9188 0.9176 0.9141 0.9106 0.9088 0.9088 0.9076 0,9036 0.9024 0.9024
7.77 7.77 7.75 7.72 7.67 7.66 7.65 7.64 7.61 7.58 7.57 7.57 7.56 7.52 7.51 7.51
0.9013
7.50
0.9013 0,9013 0.8990 0,8978 0,8978 0,8973 0,8944 0.8794 0,8493 0,8299
7.50 7.50 7.49 7.48 7.48 7.47 7.45 7.32 7.07 6.91
~ENZENE
CEN-
ilO°F. 437'F. 572'F. !10OC.)(225OC.) (300oc.) Coke
15.6'C.)
Fuel Oils B. S.
54
%
010
0.0
6.0 0.0 0.5 3.0 0.0 0.0 0.0
0.0
0.0
0.0 0.0
8.0 0.0 1.0 4.0 1.0
0.0 0.0 0.0 0.0 0.0 0.0
%
16.5 10.0 6.5 17.0 23.0 0.0 5.0 9.0 20.5 2.0
1.5 19.3 14.1 21.2 10.5 5.5 12.0 18.2 18.3 5.2 14.5 9.4
0.10 0.10 0.10 0.10 0.10 0.10 0.20 0.40
Sample exhausted 0.0 8.0 0.0 2.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 5.0 0.0 0.0 14.5 0.0 0.0
-
NETHOD
% bywt
8.0
SULFUR
!R IFU 0E
%
1o;o
,
WATER
0.05
0.05 0.10
0.40
9.4 14.0 8.8 7.5 7.7 9.3
0.40 0.20 0.10 0.10 0.10 0.05 0.10
0.00
CALORIFIC VALUE
Gross a s detd.
Dry oil basis
6 by wt.
B. t . u./lb.
B.1.u./lb.
0.10 0.20 0.05 0.20 0.10 0.10 0.60 0.05 0.10 0.05 0.00 0.10 0.05 0.18
0.10 0.00 0.05 0.00 0.10 0.21 0.05 0.21 0.10 0.10 0.63 0.05 0.11 0.05 0.00 0.11 0.05 0.19
0.29 5.45 2.84 2.77 2.62 1.54 2.67 1.10 2.76 0.85 1.83 1.48 0.95 0.90 1.60 2.39 1.09 2.03 1.58
18,340 17,772 18,242 18,275 18.408 Mi440 18,435 18,633 18,265 18,698 18,692 18,698 18,682 18,791 18,607 18,695 18,921 18,758 18,733
18,350 17,790 18,242 18,285 18,408 18,459 18,473 18,643 18,303 18,717 18,711 18,811 18,691 18,801 18,617 18,695 18,940 18,767 18,769
0.10 0.35 0.13 0.05 1.13 1.35 0.00 0.10 0.00 0.10 0 50 0.05 0.00 0.30 0.00 0.10
0.11 0.37 0.14 0.05 1.23 1.47 0.00 0.11 0.00 0.11 0.56 0.06 0.00 0.33 0.00 0.11
3.04 0.19 0.58 2.02 0.18 0.18 0.56 0.44 0.63 1.23 0.60 0.17 0.22 0.39 0.46 0.49
18,618 19,149 18,981 18,858 18,788 18,824 19,125 18,989 19,080 19,313 19,120 19,300 19,358 19,256 19,353 19,152
18,638 19,225 19,008 18,867 19,014 19,082 19,125 19,010 19,080 19,334 19,226 19,310 19,358 19,319 19,353 19,173
k brvol. % b y w t . 0.05 0.10 0.00 0.05
0.00
0.05
B. t. u,/
.
gal. 153,223 144,277 147,578 147,377 147,816 148,041 147,969 149,144 146,058 148,800 148,378 148,983 147,472 147,588 146,143 146,569 148,111 146,007 145,835 144,817 149,378 147,312 145,653 145,837 146,168 146,306 145,236 145,199 146,352 145,641 146,177 146,346 145,279 145,341 143,989
1.5
6.5 0.0 0.0 0.0 2.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0
0.0 0.0 0.0 0.0 7.5 0.0 1.5 1.5 3.0 0.0 0.0 0.0 0.0 0.0 0.0 1.5
7.5 0.0 11.0 17.0 15.5 9.0 22.0 19.0 9.0 1.0 1.0 5.0 10.0 11.5 18.0
2.0 7.8 9.2 8.2 7.7 9.1 5.0 5.1 6.2 3.8 11.3 10.2 4.8 10.0 3.5 5.0
0.05 0.40 0.10 1.40 1.60 0.10 0.03 0.05 0.10 0.50 0.05 0.15 0.10 0.05 0.10
0.0
0.0
13.0
5.1
0.05
0.10
0.11
0.60
19,277
19,287
144,653
0.10 0.10 0.10 0.10 0.07 0.10 0.05 0.40 0.10 0.00
0.10 0.18 0.03 0.00 0.20 0.80 0.00 0.40 0.05 0.00
0.11 0.20 0.03 0.00 0.22 0.89 0.00 0.45 0.05 0.00
0.46 0.22 0.77 0.43 0.19 1.19 0.57 0.96 0.22 0.17
19,182 18,185 19,205 19,322 19,475 19,053 19,309 18,869 19,627 19,890
19,203 19,223 19,211 19,322 19,517 19,205 19,309 18,954 19,637 19,890
144,023 144,173 143,890 144,529 145,987 143,461 143,852 138,743 138,834 137,440
0.0
0.0
0.0 0.0
0.0 25.0 0.0 21.0 0.0 15,5 0.0 19.0 0.0 15.0 0.0 28.0 0.0 14.0 Sample exhausted 8.5 12.5 31.0 o. o. o. o 40.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0
4.5 7.4 3.9 3.5 5.0 1.9 3.7 1.5 9.0
-
INDUSTRIAL AND ENGINEERING CHEMISTRY
October, 1929 The equation for this average curve was determined by finding the value of the constants, a and b, of the algebraic equation for a straight line:
935
6oo 300
y=b+ax
where y is the experimentally determined B. t. u. value and z is the A. P. I. gravity. The formula for the straightrun fuel oils based upon the determinations presented in this paper is
+
Calorific value = 17,010 [90 X degrees A. P. I.] (1)
,pooo 9 ~ o
x)o
''' sIo
The values in Formula 1 are 'm based upon the dry oil; this is ,adwo the usual basis for comparing oils *~~ because the water content is variable, ranging from 0 to 1.5 ,,,~ per cent. Generally, 1 per cent 9 /Z of water is equivalent to about 180 B. t. u. or 1 per cent of the experimentally determined calorific value. On Plot No. 4 the curve representing Formula 1 developed in the present work for straight-run fuel oils has a steeper slope than the average curve for straight-run fuel oils. For A. P. I. gravities below 24 degrees the average calorific values per pound are smaller than other investigators have estimated them, while for A. P. I. gravities above 24 degrees they are higher. Table I summarizes the data collected for the various straight-run fuel oils, arranged according to increasing gravity and increasing calorific value. /O
I/
I3
rQ
/S
/6
/7
Experimental Work on Cracked Residuums The samples of residuum analyzed in this work came from selyral types of domestic crude oils. They were analyzed for Tvater, sulfur, light-oil content, and B. S. by the methods used
/8
0
20
d/
22
63
29
& 7
ie Prcmwn
26
67
28
29
30
3/
32
33
34
3 7 .
36
37
36
Jo
for the straight-run fuel oils. The calorific values have been corrected for the water content, which did not exceed 0.5 per cent by weight in any sample. The results of these analyses for both normal and flashed residuurns have been summarized in Table 11. The curve shown on plot KO.3 represents the calorific values given in Table 11 for the dry oil, The equation for this curve establishcd by the method used for the straight-run fuel oils is as follows: Calorific value = 17,645
+ j54 x degrees A . P. I.]
(2)
This equation is about the same as that proposed by LeConte; hence the curve for cracked residuum has substantially the same slope as the LeConte curve and differs considerably from the curve developed for straight-run fuel oils. There is very little difference between the calorific values of normal and flashed residuums as long as both have the same gravity, hence the same formula may be used f o r c a l c u l a t i n g the calorific value of either kind of residuum. A comparison of the calorific values obtained from the other curves is given in Table 111. The above figures show that the B. t. u. values per pound calculated from Formula 2 a p proximate the average values for all the formulas found in the literature for the various gravities, but that there is quite a wide variation between those calculated from Formula 1and those from the average of all the formulas. The relationships are shown on Plot No. 4. Averaging the comtants in the formulas found in the literature gives
+
Calorific value = 18,042 [47 X degrees A. P. I.] (3)
Table 11-Dubbs TYPEOF CRUDE
"$ :,-
OF
bing, and Peabody Midcontinent Mixed Kansas Midcontinent California Mixed Kansas Potwin, EIbing, and Peabody Midcontinent Midcontinent Midcontinent Ventura, Calif. Smackover, Ark. Midcontinent Mixed Kansas Potwin, Elbing, and Peabody Ventura, Calif. Midcontinent Midcontinent Kentucky Midcontinent California Midcontinent Mixed Archer and Wichita co. Ventura, Calif. Mixed Archer and Wichita co. Mixed Archer and Wichita co. Midcontinent ElPotwin, bing, and Peabody Pennsylvania Pennsylvania
Cracked Residuums
ENCLER DISTILLATION
SP. GR. A. P. I. 6O0/6OoF. GRAVITY (l5.6'/ 15.6'C.)
IIO°F. 437'F.
572'F. 210OC.) 1225'C.) 1300°C.) Coke
Lbs./gal
Degrees Blend: Hendricks and McCamey, W. Texas Kentuckv
Vol. 21, No. 10
INDUSTRIAL AND ENGINEERING CHEMISTRY
936
B. S.
CALORIFIC VALUE
ENZENE
WATER
ENTRIFUGE
SULFUR
Dry oil basis
Gross
- as detd.
IETHOD
$ by u?t
70
B.f.u./ lb.
B. t . u . / lb.
B. t. u . / gal.
0.50 0.00 0.00 0.10 0.25
0 47
18.1
24.0 Solid 16.0 10.0 0.8
00 00 10 25
2.92 0.41 1.20 1.37 0.67
1'7,118 17,837 18,130 17,970 18,077
9.0 0.0 8.5 12.0 6.0 3.0
11.1 24.0 21 3 23.2 13.4 21.0
1.0 1.8 14.0 11.0 0.3 2.6
0.00
0.00
0 00 0 00 0 20 0 00 0 05 0 40
0.56 0.92 0.69 1.18 1.20 0.68
18,277 18,162 18,122 18,052 18,084 18,274
18,277 18,162 18,162 18,052 18,093 18,347
153,892 152,379 152,379 151,456 151,800 153,381
0.0 0.0 0.0 4.5 0.0
8.0 3.0 3.0 20 0 2.0
19.6 17.0 17.4 14.6 25.1
4.4 0.2 0.2 2.5 1.4
0.10 0.00 0.00 0.05 0.30
0 0 0 0
10 00 00 05 0 30
0.57 0.77 0.87 0.73 1.49
18,091 18,293 18,250 18,210 18,088
18,109 18,293 18,250 18,225 18,142
151,391 151,649 151,293 150,539 149,672
0.0
0.0 6.0 0.0
20.0 15.0 2.0
18.0 24.0 19.6
1.2 8.0 1.1
0.00 0.00 0.00
0 00 0 00 0 00
3.12 0.78 0 65
18,152 18,279 18,461
8.20 8.17 8.13 8.08 8.03 7.98 7.96 7.90
0.0 2.0 2.0 1.0 5.0 5,O 3.5 1.0
1.0 3.0 3.0 1.5 8.0
17.4 15,i 16.2 11.5 11.6 4.5 4.9 17.3
3.2 1.2 2.4 0.0 6.0 0.0 0.1 2.7
0.05 0.00 0.10 0.05 0.05 0.10 0.05 0.00
0 05 0 00 0 10 0 05 0 05 0 10 0 05 0 00
0 58 1.48 0.72
5.0 2.0
12 5 13.5 18.0 18.0 30.0 25.0 40.0 21.0
0.30 0.63 1.14 0.62
18,421 18,205 18,386 18,454 18,651 18,487 18,319 18,604
18,430 18,205 18,404 18,460 18656 18:506 18328 18:604
151,126 148,735 149,625 149,157 149808 147:678 145891 146:972
0.9427 0.9421
7.86 7.85
2.0 0.0
2.5 1.0
13.0 9.0
6 2 10.2
0.8 0.3
0.00 0.10
0 00 0 10
0.79 1.40
18,732 18,592
18,732 147,046 18,611 146,096
19.9
0.9346
7.78
3.5
4.5
19.0
11.0
0.3
0.00
0 00
0.81
18,170
18,710 145,564
H. P. H. P.
20.6 21.4
0.9303 0.9254
7.75 7.71
3.0 0.0
4.0 0.0
18.5 7.0
10.9 13.2
a.3 0.5
0.00 0.10
0 00 0 10
0.81 0.27
18,756 19,074
18,756 145,359 19,093 147,207
H. P. H . P. H. P.
22 0 25.3 32.3
0.9218 0.9024 0.8639
7.68 7.51 7.19
8 0 2 0
4.2 7.1
0.2 0.9 0.1
0.05 0.20 0.05
0 05
0.42 0.17 0.16
18,778 18,959 19,494
18,787 144,284 19,001 142,698 19,504 140,234
H P . L P. H. P. H P . H. P.
0 0 3 3 7 2 7 6 8 1
l.Oi60 1,0500 1.0220 1.0170 1.0140
8.96 8.75 8.51 8.47 8.46
0.0 0 0 4 5
L. P.
1.0110 1.0070
L. P. L. P.
8.6 8.9 8.9 8.9 8.9 9.2
1,0070 1.0070 1.0030
8.42 8.39 8.39 8.39 8.39 8.36
0.0 0.0 0.0 3.0 0.0 0.0
0.0 0.0 1.5 3.5 0.0 0.0
H. P. L.P. L.P. L. P. L. P.
9.2 10.7 10.7 11.2 11.3
1,0030 0.9961 0.9951 0.9916 0,9909
8.36 8.29 8.29 8.26 8.25
0.0 0.0 0.0 3.5 0.0
I, P. H. P.
L. P.
11.3 11.6 12.2
0,9909 0.9888 0,9847
8.25 8.23 8.23
H. H. H. H. H. H. H. H.
P. P.
12.2 12.8 13.5 14.3 15.2 16.1 16.5 17.6
0.9847 0.9806 0,9759 0.9706 0.9646 0.9587 0.9661 0,9490
H. P. H. P.
18.6 18 7
H. P.
L. P. L. P.
H . P.
P. P. P. P. P.
P.
1.0070
8 0
0 0
:.:
0 0 13.5 Samole exhausted 3.0 4'. 0 16.5
5.0 0.0
7.0
10.5 39.0 34.0 3 5 Sample exhausted
42.0 32.5 24.0
0.00 0.20
0.05 0.40
a K. P. represents usual residuum produced a t a high pressure by normal residuum operation. operation a t low pressure.
Relation between Carbon and Hydrogen Content and Calorific Value
Representative samples of commercial cracking stocks and the normal and flashed residuums made from them were analyzed by the Fisher combustion-tube method (.5), following the modified procedure used by the University of Illinois (private communication). The results of these determinations are summarized in Table IV. I n the majority of cases the normal residuum showed a lower carbon and a higher hydrogen content than the flashed residuum. The flashed residuum showed a higher carbon and lower hydrogen content than the cracking stock. After considering the water and the sulfur content, there was only about 1 per cent of material unidentified in most of the samples. The California samples had as much as 2 per cent unaccounted for, the result, perhaps, of the presence of nitrogen and oxygen compounds in them. Some California oils contain as much as 2 per cent of nitrogen. The average ratio by weight of carbon to hydrogen in the cracking stocks is 7.08; in the flashed residuums, 9.22; and in the normal residuums, 8.66. Several formulas have been proposed for calculating the calorific value per pound of oil from the percentages of carbon, hydrogen, sulfur, and oxygen. The values given in column 10 of Table IV were derived by substituting the percentages of these constituents in the Dulong formula ( 2 ) :p. 480, which
0 0 0 0
0 22 0 05
0.70
L. P. represents flashed residuum produced by Bashing
has been adopted by the American Society of Mechanical Engineers. This formula is as follows: Calorific value (in B. t. u. per pound) = 146 C 4-620 ( H - : ) + 4 0 S The calorific values calculated by the above formula are higher than those experimentally determined by the bomb calorimeter as shown by a comparison of the values in columns 10 and 11. The cracking stocks show an average of 1077 B. t. u. per pound more heat units than were determined experimentally, while the residuums, either normal or flashed, show an average excess of 740 13. t. u. per pound. Table 111-Comparison
of Calculated Calorific Values of Residuums w i t h Those of Fuel Oils 100 A.P.I.
15' A.P.I.
ZOO
A.P.I.
25' A.P.I.
30' A.P.I.
~~
B . t . u./lb. B . f .u./lb. B. t . u./lb. B. 1. u./lb. B.t. u . / l b . Cross or Haslam and Russell Sherman-Kropff Dice N. Texas Fenn LeConte Average Straight-run fuel oils developed in present work, Formula 1 Cracked residuums developed in present work. Formula 2
18,695 18,650 18,565 18,500 18,380 18,280 18,512
18,746
18,979
19,222
19,450
17,910
18,360
18,810
19,260
19,710
18,185
18,455
18,725
18,995
19,265
I N D US TRI A L A X D E AiGIXEE RING C H E MIX T R Y
October, 1929
Analyses of Commercial Fuel Oils and Cracked Residuums
Table IV-Ultimate
STOCK
CRUDE OIL
California Midcontinent Lfidcontinent Llidcontinent California
Cracking Flashed residuum Normal residuum Cracking Flashed residuum Normal residuum Cracking Flashed residuum S o r m a l residuum Cracking Flashed residuum S o r m a l residuum Cracking Flashed residuum Normal residuum Cracking Flashed residuum ?iormal residuum ~~
a
A. P. I. GRAVITY Water Degrees 24 4 3 3
Carbon
n /C
c
(7 .c
..
87 1 90 6 88 7 85 8 88 3 87 5 86 4 88 5 87 6 86 5 88 9 87 4 86 2 88 4 88 5 85 6 86 5 87 5
12.53 8.49 10.23 12.09 9.50 10.17 12.38 9.92 10.27 12.38 9.80 11.10 12.39 9.95 9.07 11.40 10 04 9.38
0 :05 0.89 0.05 0.05
15 2 26 2 89 16 5 25 3 10 7 14 3 25 5 8 6 22 0 25 1 9 2 8 1 18 7 11 3 7 6
.. 0 : 05
.. 0 : 05 0.33 0.40 0.25 0.05 0 30 0 10
Gross B. t . u. per pound observed-[(pound
Hydrogen
H2 X 9)
T
Ratio C:H
Sulfur
6 95 10.7 8 65 7.10 9.30 8.60 6.98 8.93 8.53 6.99 9.06 7.87 6.96 8.88 9.76 7.50 8.65 9.33
0 22 0.41 0 30 1.19 1.20 1.14
+
NET"
Vndetd. ,Calcd. from D'-
5:
%
B . 1. u . / l b . 20,494 18,506 19,292 20,068 18,748 19,146
0.15 0.50 0.72 0.04 0.95 1.14 0.76 0.81 1.38 0.76 0.74 1.03 0.69 0.81 1.51 1 35 1.67 1.65
0.46 0.77 0.70 0.46 0 56 0.42 0.39 0 68 0.67 1.60 1.49 1.37
20,308 19,077 19,667 20,286 19,102 18.577 19,639 18,910 18,648
B
1. u . / l b . 19,358 17,837 18,651 19,053 18,084 18,319 19,353 18,293 18.454 19,182 18,277 18,778 19,256 18,274 18,077 18,607 18,088 17,970
B . 1. u.,/Lb. 18,168 17,030 17,677 18,001 17,179 17,351 18,173 17,349 17,479 18,002 17,345 17,723 18,076 17,324 17,219 17,522 17,128 1i,oi5
1
the same pour points and much higher viscosities thaii the cracking stocks. The A. P. I. gravities of the flashed residuurns usually are lower than those of the normal residuuins; this being the case, thc B. t. u. value per pound of flashed residuum nil1 be lower and the E. t. u. value per gallon will be higher thaii for iiorinal residuums. In most cases the B.t. u. value per pound of flashed residuum for approximately the same A. P. I. gravity is a little lower, but the values a. s h o ~ mon I'lot s o . 3 fall above and below tlie arerage curve with about the same regularity.
-
u
I n the calorimetric method for determining the calorific value of a fuel oil the hydrogen in the oil burns t o water and the products of combustion are cooled to the initial temperature of the oil-i. e., 62" F. (16.7"C.): themaximumor gross heat available from the oil i b measured. This gross calorific value has been accepted as the standard value by the Xmerican Society of Xechanical Engineers. In Great Britain and nlanT' European countries tlie lower calorific value is accepted. In furnace operatlons the same reactions occur as in the calorlmetric bomb; the products are cooled. but the water w p o r is not condensed. The gross fuel value, therefore, 16 correc-ted for the heat of vaporlzstion of the water. The resulting value is knov n as the net calorific value. Attempts t o inake u5e of the loiver heat value; iutro-
Gross I3 t u per lb o b s e n e d [(per cent H X 9) per cent H20 in oil a t s t a r t ] 1 0 5 i = net B t u per Ib
VALUE
GROSS
pound H?O present] 1057 = net B. t . u per pound.
Calculation of Net Heat Value for Fuel Oils and Cracked Residuums
cluce a source of possible error 1)ecaii.e an improper tenipc>rature of cooling is generally asqumed. The figures qhonn in the 1a.t coluriiri of Table IT- are the calculated iict calorific ~ a I u c 5per pound uf oil including the n ater already pieient in the fuel oil. Tliii correction i i applied hy uiIlia tll? follon 1ng iornlU!a'
CALORIFIC
,
ANALYSES-WEIGHT BASIS
S O U R C E OF
Kentucky
937
Effect of Source of Crude Oil on Calorific Value
The data given in Table I show no tlefinite relatioll-lilI) between the source of the fuel oil and the calorific v:ilue3 m c e this value weins to be purely a function of the gravity. Some Callfornla fuel 011' have low calorific values and some h g h ,
,a, ~ o c
80
Jao I o
Comparison of Normal and Flashed Residuums w i t h Corresponding Cracking Stocks
nO
The data i n Table T-erere reasbrnibled from Tables I and I1 t o shou the coiripciri+on betn rei1 (c 0 tlie original cracking .tacks and ' the nollnal alld fla.l,ed reql(luuins made by c r a c h i i i g them. Other data, such as pour point and viscosity, have been included. General illspection of the data shows the normal residuurns to have lower pour points and lower viscosities than the origlnal crackiiig stocks. Thp flashed residuums have about ~~
-,b
,500
1
\
.
\
.
! ! !f / ! ! ! \
\
\
o!
/c
!.b, k ! dC/
RA
,7r
% P I G R a V I T V' 7
;9
!e
1
I1 L, !e
1
1
a
w
depending upon n hether the gravity is low or high. Furthermore. a 22 3" -1.P. I. gravity fuel oil made from C'omodoro Rivadaria crude oil (Argentine) has subitantially the same calorific value as a 22 5" d.P.I. fuel oil made from Panhandle (Texas) crude oil. A number of similar comparisons may
INDUSTRIAL A N D ENGINEERING CHEMISTRY
938
Table V-Comparison
AKD
A. P. I. SP. GR.
TYPEOF CRUDE
" : ; -
Vol. 21, KO. 10
of Normal a n d Flashed R e s i d u u m s w i t h Cracking Stock
ENGLER DISTILLATION
CALORIFIC VALUE POURPOINT
(1:0;?&,)
FUROL VISCOSITY Obsd.
Corrected for Hz0
~~
7,
Degrees CRACKING STOCKS:
Ventura, Calif. California Midcontinent Okla. Midcontinent Mixed Kansas Midcontinent Mixed Kansas Midcontinent Midcontinent Archer and Wichita Cos., Texas West Texas Kentucky
70 bs Wl.
70
% bs luf.
70
by
Wt.
c.
O F .
F
c.
3.1,u./
B.t.u./
B.t.u./
Ib.
Ib.
. . . .
..
18,607 19,053 19,322 19,353
18,617 19,205 19,322 19,353
146,143 143,461 144,529 145,341
Sec.
4.5
0.10
0.11
0.46
38
2 5 . 1 0.9036 2 5 . 3 0.9024
Sone 10.0 1.0 5.0
0.10 0.10
0 33
a. 11
0.39 0.49
38 46
+ 6.1 +4- 051 ... 061 + 3.3 ++ 73 .. 83
25.5 0.9013 1 9 . 9 0.9346 24.4 0.9076
None None None
5.1 7.7 4.8
0.05 0.05 0.15
0 11 0.05 Xone
0.60 2.03 0.22
32 12 52
0.0 -11.1 +11.1
10.00 0.10 8.00 None
0.10 0.05 None 0.05
1.37 1.14 0.78 0.70
40 4.4 ,elow 0 - 1 7 . 8 12 -11.1 #elow0 - 1 7 . 8
ii
ii
25
i7
77
25
- 17.8
14
77
18 7 26.2 26.1 25.3
0.9421 0.8973 0.8978 0.9024
A-one 1 4 . 0 None 1 . 9 None 3 . 5 None 3 . 5
0.10 0.10 0.10 0.05
0.05 0.89 None None
1.60 1.19 0.43 0.46
43 42 34 32
25.5
0.9013
A-one
NORMAL RESIDUUMS:
+
77 77 77
25 25 25
23
77
25
19,182
19,203
143,989
16
66
122 77
50 1 25
19,256 19,152
19,319 19,173
145,279 143,989
42 178 151
77 77 77
25 2.5 25
19,277 18,758 19,358
19,287 18,767 19,358
144,653 146,007 146,348
17,970 18,319 18,279 18,454
17,988 18,328 18,279 18,460
152,355 145,891 150,436 149,157
14 39 60
Ventura, Calif. California Midcontinent Okla. Midcontineqt Mixed Kansas Mldcontinent Mixed, Kansas Midcontinent Midcontinent Archer and Wichita Cos., Texas West Texas
7.6 16.5 11.6 14.3
1.0170 0.9561 0.9888 0.9705
3:5 419 5 . 0 24.0 1 . 0 11.5
22.0
0.9218
8.0
4.2
0.20
0.05
0.42
,elow 0
8 . 1 1.0140 1 3 . 5 0.9759
3.0 2.0
18.1 16.2
0.80 2.40
0.26 0 10
0.67 0.72
elow2 - 1 6 . 7 elow 6 -14.4
24
122
18.6 0.0
0.9427 1.0760
2.0 6.2 None 42.0
0.80 24.00
None 0.47
0.79 2.92
20
Kentucky RESIDUUMS: Ventura, Calif. California Midcontinent Okla. Midcontinent Mixed Kansas Midcontinent Mixed Kansas hlidcontinent Midcontinent Archer and Wichita Cos., Texas West Texas Kentucky
15.2
0.9646
11.6
6.00
0.05
0.30
elow0 - 1 7 . 8 .oom Too vis?mp. cous elow0 - 1 7 . 8
1 1 . 3 0,9909 8 . 9 1.0070
Kone 25.1 None 1 3 . 4
1.40 0.30
0.30 0.05
1.49 1.20
50 21
10:7
0.9951
i d n e 17:0
0 : io
kine
0:77
8.6
1.0110
None 1 7 . 1
1.00
None
0.56
9.2
1.0030
None 21.0
2.60
0 40
..
.. ..
Skid
Ndne
FLASHED
-
..
....
....
5.0
..
....
. . . . . . . .
3:3
1,050
Nine 32:s
....
..
be selected from the data given in Table I, with substantially the same conclusions. Effect of B. S . Material on Calorific Value
The B. S. content of all straight-run fuel oils tested was less than 0.5 per cent; hence this small quantity of material does not have a prejudicial effect upon the calorific value of the fuel oil. Several of the cracked residuums, however, contained appreciable quantities of B. S. material. Those containing over 10 per cent of B. S. as shown by the benzene-centrifuge method were centrifuged with benzene to obtain B. S. material for examination. The mixture of oil and benzene was fractionally distilled to recover the benzene, and the calorific value of the oil free from B. S. was determined. The solid B. S. material was freed from benzene and the calorific value determined. Table VI summarizes the analytical data obtained in these tests. The isolated B. S. material has an average calorific value of 16,015 B. t. u. per pound or about 2000 B. t. u. per pound less than the oil containing no B. S. One per cent by weight of B. S. material causes, therefore, a lowering of 20 B. t. u. I n the majority of the cases where the B. S. content is very small, it will have no practical effect on the calorific value per pound. The only effect of importance comes when the B. S. content exceeds 10 per cent by the benzene-centrifuge method. One per cent of B. S. as determined by the benzenecentrifuge method is considered to effect a lowering of the calorific value of 10 B. t. u. per pound. For a B. S. content of 2 per cent (specification for a marketable residuum) the correction for the B. S. material would be 20 B. t. u., a quantity which is less than the allowable experimental error in determining the calorific value.
gal.
.. ..
25
18,778
18,787
144,281
50.1
18,077 18,386
18,122 18,404
153,312 149,625
77
25
18,732 17,118
18,732 17,198
147,046 154,094
20
77
25
18,651
18,656
149,808
+10.0 6.1
174
77
18,088 18,084
18,143 18.093
149,672 151,800
43
+ 6,l
124
122
50: 1
18,'293
18,293
151',649
25
-
3.9
52
122
50.1
18,277
18,277
153,892
0.68
42
+. . 5. .. 6
159
122
50.1
18,274
18.347
153,381
0:41
.oom
Too viscous
.. ..
..
.. .. ..
:mp.
....
.... ....
. . . .
..
. . . .
.. . . . . .
I
..
..
25
..
............. ............. . . . . . . . . . . . . .
17,837
17,837
156,074
Composition of B. S. Material in Cracked Residuums
A flashed residuum made from a California cracking stock which contained 0.8 per cent of B. S. material was used for the study of the composition of the B. S. The B. S. material was separated in the manner described above, and the dry benzene-free solid was ground to a fine powder before analyzing it. Combustion analysis on this dry B. S.material showed the following composition: Carbon Hydrogen Sulfur Noncombustible Undetermined Total
Per cent 70.60 5.51 2.83 17.80 3.26
IOO.00
The inorganic material remaining in the combustion boat seemed to be of a siliceous nature. An ignition of the B. S. material showed 8.10 per cent of ash. The rest of the 17.8 per cent of noncombustible matter (9.7 per cent) was lost by thermal decomposition between the temperature of the Fisher combustion tube, 700" C. (1292' F.), and that of the platinum crucible, 940" C. (1724' F.). This apparently high content of inorganic matter and ash when reduced to the basis of the original residuum amounts to 0.14 per cent of inorganic material and 0.05 per cent of ash. This is not a n unusually high ash content for residuum made from a fuel oil where the inorganic material present in the fuel oil may be concentrated in the cracked residuum. The dry B, S. material was found to be soluble to the extent of only 1.3 per cent in petroleum ether. An extraction of the material insoluble in petroleum ether with carbon tetrachloride showed 33.8 per cent of soluble matter based on the
I N D U S T R I A L A N D ENGINEERING CHEMISTRY
October, 1929
original €3. S.material. The material dissolved by the carbon tetrachloride contained: Per cent 81.90 9.10
Carbon Hydrogen Ratio C:H Sulfur Undetermined
....
8.99
4.80 4.20
Total
100.00
This material has a chemical composition like that of a hydrocarbon oil and about the same ratio of carbon to hydrogen as a flashed residuum. Value of B . S . Material
Table VI-Calorific B. S B Y SAM-
PLB
CALORIFIC V A L U E OF
‘.
::::-
BENZ’ENE‘IN CENTRIFUGE
B.
AS
detd.
~IETHOD
% 1
24.0 16.0 14.0 11.0
2 3
4
915 1.55
1
1B.t.
Total
Per cent 69.80 8.07
....
12.67 9.46
s. h f A T E R I A L
Free oil
Original oil
u./lb. B. 1. u./lb. B . t . u . / l b . B. t . u . / l b
15,650 16,150 16,106 16.155
A f u r t h e r extraction with carbon disulfide of the portion insoluble in carbon tetrachloride removed 10 per cent more of the material. The portion soluble in carbon disulfide had the following composition: Carbon Hydrogen Ratio C:H Sulfur Undetermined
S-free basis
B.
8.63
100.00
The ratio of carbon to hydrogen is substantially the same as that of a cracked residuum. As a check on the above determinations some of the original B. S. material was extracted directly with carbon disulfide;
16,026 16,327 16,236 16.345
17,434 17,952 18,171 18.176
17,118 18,130 18,126 18.052
939
42 per cent of the material dissolved. Analyses of the extracted portion and the portion insoluble in carbon disulfide were as follows: EXTR.4CTED PORTION
Carbon Hydrogen Ratio C:H Sulfur Undetermined Total
Per cent 77.00 8.50 ,
.. .
10.00 4.50
--100.00
9.05
INSOLUBLB IN CARBON DISJLFIDB Per cent Carbon 60.00 Hydrogen 3.34 Ratio C : H . . .. 17.9 Sulfur 3.06 Noncombustible residue 26.07 Undetermined 7.63 Total
100.00
The carbon disulfide dissolves all that is soluble in petroleum ether and in carbon tetrachloride. The dissolved material has about the same percentages of carbon and hydrogen as ordinary residuum. The components of petroleum products that are soluble in petroleum ether are usually called “petrolenes,” while those that are insoluble are termed “asphaltenes.” That portion of the asphaltenes that is insoluble in carbon tetrachloride but
INDUSTRIAL AND ENGINEERING CHEMISTRY
940
soluble in carbon disulfide is called "carbenes." basis the B. S. material contained:
On this Per cent 1.3
Petrolenes Asphaltenes contaminated with inorganic substances
98.7
The 98.7 per cent of asphaltenes is composed of: Per cent Carbenes 10 0 Material insoluble in carbon tetrachloride but soluble in carbon disulfide 33 8 Carbonaceous material insoluble in carbon disulfide but combustible 42 6 in oxygen a t 700" C. (1292' F.) Insoluble and noncombustible matter 12 3 98 7
Total asphaltenes
' The material which is insoluble in petroleuin ether, carbon tetrachloride, and carbon disulfide amounted to 54.9 per cent of the dry B. S. material. Combustion analysis of this material showed it to contain:
Per ceitl 64 20 3.49
Carbon Hydrogen Ratio C:H Sulfur Noncombustible Undetermined
....
184
3 27 22 30 6 74
100.00
Total
The high ratio of carbon t o hydrogen indicates the predominance of carbonaceous matter in that portion of the B. s. material that is insoluble in carbon disulfide. The solubility in chloroform and aniline after extraction with carbon tetrachloride and carbon bisulfide TTas negligibly small. The solubility of the dry B. S.material in various solvents is shown by the following tabulation: Per cent 4 s 74
Chloroform Carbon disulfide Benzene Aniline Carbon tetrachloride
44 82 44 68 44 6 1 39 6 5
The solubility in the various solvents is of about the same order. Carbon disulfide is a better solvent than carbon tetrachloride, a relation which checks the results previously mentioned. Benzene, aniline, and carbon disulfide are ahout equal in solvent poTver. The following flow chart summarizes the distribution of the various fractions: c ;
SOLIDB. S. MATERI.AL-
Per cent C H
S
h70ncombustible Undetermined Total
Ash
70.60
5.51 2.83 17.80
3.26 100.00
8.10
byr-1.
-PETROLEUM ETHER-SOLUBLE. ...... 1.3 X o analysis of dissolved oil was made. I K CARBON TETRACHLORIDE. . 33 S -SOLUBLE Grams 1 % b y r d !Ratio C . H 27 66 81 9 8 99 C H 3 1 6081 1 S Undeter1.45 1 0 L ~ mined 3 3 0 __ DISULFIDE.. . . . 10.0 -SOLUBLECARBOB Grams 1 % b y wt, IRatio C : H 0 898 6 1 1 69 8 080 71 8 65 C H 1 27 12 67 S Undetermined
1
:A
j 1
RESIDUE. ..............
--INSOLTBLB
TOTAL ......................... I Grams
mined
i
+!? 04.90
1%
100 0
b v w i . IRatio C : H
1V .? I 100.00
Vol. 21, No. 10
Effect of Light-Oil Content on Calorific Value I n Tables I and I1 the percentages distilled a t 410' F. (210' C.), 437' F. (225' C.), and 572" F. (300" C.) have been recorded for each fuel oil and residuum as an indication of the volatility. I n all cases except three the quantity of material boiling within the gasoline boiling range was negligible; hence no correction for the calorific value of the gasoline content is necessary. I n the case of the three exceptions a maximum of 8.0 per cent material boiling in the gasoline range was found. The presence of this quantity of low-boiling material ail1 not have much effect upon the calorific value per pound. Removing it would lower the gravity only slightly, which would consequently lower the calorific value per pound. I n Table I1 the cracked residuums show varying amounts of material boiling in the gasoline range, but in no case does the quantity exceed 11 per cent, the general average being approximately 5 per cent. This quantity is not sufficient t o cause an important change in the B. t. u. per pound recorded in the table. Uorpurgo ( 8 ) proposed a formula for calculating the calorific value of a liquid fuel oil that uses certain fractions and the coke formed by Engler distillation. The method of analysis is so complicated that a direct bomb determinatiop is quicker and more reliable. The coke produced during Engler distillation is purely a function of the nature of the oil and does not shorn a definite relationship to the calorific value of the oil. Generally, but not always, the lower the gravity of a residual oil. the higher the percentage of coke formed by Engler distillation; hence the lower the B. t . u. value. Calorific Value on Volume Basis The formulas used for calculating the B. t. 11. per pound for either the residual fuel oils or cracked residuums may he used for calculating the calorific value per gallon by introducing the additional factor of weight in pounds of one gallon of thc oil. These values, when plotted, should not produce a straight line, because the relationship between the weight per gallon and the A. P.I. gravity does not give a straight line. The calorific value per gallon of dry oil has been plotted against the A. P. I. gravity in Plots Kos. 5 and 6 for the r e d u a l fuel oils and residuums, respectively. The calorific value per gallon of oil decreases as the A. P. I. gravity increases, contrary to the behavior of calorific w l u e per pound. Usually the oils of low gravity and low price have the lowest calorific .i-alues per pound but the highest per gallon. Oil iq generally sold by the rolunie; hence the importance of condering the calorific value on the basis of the gallon. S u m m a r y and Conclusions 1-A definite correlation between the A. P. I gravity of straight-run fuel oils and cracked residuums and the 13. t. u. value per pound has been established. This relationship is a straight-line function. 2-Knowing the A. P.I. gravity of either the fuel oil (cracking stock) or the cracked residuum, whether the latter be of the flashed or normal type, the I3. t. u. value per pouiid or per gallon of oil can be calculated from the folloring equations: B t u per pound of straight-run dry fuel oil = 17,010 90 X degrees A P I B. t u per pound of dry cracked residuum = 17,645 54 X degrees A P. I
+ +
(a)
(b)
The calorific value per gallon is determined by multiplying the calculated calorific value by the weight of a gallon of the fuel oil or residuum. 3-The calculated values for the dry oil are accurate t o within 30 B.t. u. of the values determined experimentally b y
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 hare 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. The 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 OIL D Cohrp,\xY, RICHMOND. CALIF USIVZRSITY OF CALIFORSI.I, BBRKEI.ET.CALIF.,A N D S T A N D A R
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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