Flue Pro of Indust Graphical Estimation
of
Dew Points
JESSE S. YEAW AND LOUIS SHNIDMAN Rochester Gas and Electric Corporation, Rochester, N. Y.
0
HE principal constituents of the flue products resulting from the combustion of industrial fuels with air are nitrogen, oxygen, carbon dioxide, and water. Small amounts of the oxides of sulfur are also generally present, and oxides of nitrogen are sometimes reported. As these gases cool, a temperature is finally reached a t which water vapor condenses. This temperature, called the “dew point,” is the point a t which the vapor phase is in equilibrium with a minute quantity of the liquid phase in any system. Information concerning the dew points of flue gases has recently become important in industry because of two principal factors: the increasing use of liquid and gaseous fuels in place of the solid fuels formerly employed, and the improvement in the design of equipment for industrial, commercial, and domestic use to obtain the maximum recovery of the available heat. The flue products from the combustion of gaseous and liquid fuels contain a higher fraction of water vapor than do the flue products from the combustion of solid fuels because (a) the percentage of hydrogen in most gaseous and liquid fuels is higher than in solid fuels, and (b) the combustion of gaseous and liquid fuels is more easily and accurately controlled than in the case of solid fuels, and the dilution of the flue products with excess air is therefore reduced, Since the improvement in the heat recovery of industrial,
commercial, and doiiiestic equipment tends to reduce the flue temperatures, the condensation of moisture in the flueb, economizers, preheaters, and/or chimneys becomes a serioua problem which must be considered in the installation of the equipment. The problem is complicated by the fact that these condensates contain not only moisture, but also oxygen and the acidic oxide gases of carbon, sulfur, and nitrogen; and they have, therefore, a very corrosive action on the surfaces with which they come in contact. It is the purpose of the present paper to present charts from which the dew points of the flue products resulting from the combustion of industrial fuels with various amounts of excess air may be rapidly estimated.
Theoretical Dew Point The theoretical dew point is calculated by assuming that the flue gas consists of a mixture of water vapor and an inert gas, and the results are, therefore, based upon the vapor pressure data for water. The quantity of water vapor in the flue gas may either be determined directly or be calculated from the chemical equations involved in the oxidation of the fuel, to which is added a quantity brought into the flues in the fuel itself, in the air used in the combustion of the fuel, and in the excess air supplied. The results are fitted into a vapor pressure table for water or they may be plotted on a chart such as Figure 1, which was obtained from the vapor pressure data 999
A series of curves, based upon the calculated dew point data for the flue products of a number of industrial fuels (solid fuels, fuel oils, and gaseous fuels of as widely varying composition as could be found in the literature) are included on one chart. With this chart theoretical dew point data for the flue products of any ordinary industrial fuel with any quantity of excess air can be estimated with an accuracy about equal to that to be expected in the reading of the chart itself, and sufficiently accurate for all practical purposes. The quantity of air required and the flue products resulting from this combustion can be roughly estimated from the heat value of the fuel. A series of curves is included, based upon the limited amount of vapor pressure data for water-sulfuric acid solutions available, showing the effect of sulfur trioxide upon the dew point for certain flue gas mixtures. The deviation in the dew point data due to the presence of sulfur trioxide must be recognized, since the theoretical dew point alone is valueless from the practical standpoint.
sented in Tables 111, IV, and V, and the deviations of the curve readings from the calculated dew points shown in the last columns, i t seems safe to conclude that the theoretical dew point for the flue products of any ordinary industrial fuel may be estimated by the use of the curve with an accuracy about equal to the expected deviation in reading such curves and sufficiently accurate for practical purposes. After calculating the dew point of the flue products of the theoretical air-fuel mixture which represents the complete combustion of the fuel as shown in Tables I and 11, it is simple to increase the quantities of excess air and to calculate the dew point for any mixture of these flue products with air. These data fall along certain d e f i n i t e curves when plotted on a chart depending upon the value of the dew point for the flue products of the
The calculated dew points for the flue products of the theoretical air-fuel mixtures for a variety of industrial fuels are I shown in Tables 111, N,and V. In obtaining these data, i t was assumed t h a t : 1. The chemical equations involved in the oxidation express true volume and weight relations. 2. The volume of 1 pound mole of any of the gases equals F 378.4 cubic feet at 30 inches of mercury and 60" F. 3. All air supplied is 50 per cent saturated at 60" F. (0.87 c 3 per cent water by volume). 2 Sample calculations of the dew points are given in Tables I and 11. When the dew points for the flue products of the theoretical air-fuel mixtures for solid and liquid fuels are plotted against the weight ratio, hydrogen/(carbon sulfur), they fall along smooth curves as shown in Figure 2. In the case of the gaseous fuels the dew points vary with the B. t. u. per cubic foot of the fuel. Considering the wide variety of fuels repre-
+
PERCENT DRY AIR IN TOTAL D R I FLUE PRODUCTS
SEPTEMBER, 1936
IXDUSTRIAL AND ENGINEERING CHEMISTRY
CALCULATION OF DEWPOINT FOR TABLE I. SAMPLE FUEL(VOLUME BASIS)
A
TABLE11. SAMPLE CALCUL.4TION OF DEWPOINT OR LIQUID FUEL(WEIGHTBASIS)
GASEOUS
-Cu.
-Cu. F t . per Cu. F t . of Gas Burned-In Combustion ProductsO! N2 HzO required CO:
Fuel Analysia, R. b. v Vol. 1.7 HrO 50.0 Hz 10.0 co 24.3 CHd C1H4 2.0 1.0 CsHa 3.0 coz 8.0 Nl
0.000 0.000 0.100 0.243 0.040 0.060 0.030 0.000
0.000 0,250 0.050 0.486 0.060 0,075 0.0
0.0 -
-
0.017 0.500 0.000 0.486 0.040 0.030 0.000 0.000
-
--
Fuel Analysis, % by Wt. 10.17 Ash 0.67 52 Hz 3.47 C 79.49 Na 1.10 5.10 Oa
0.000 0.940 0.188 1.827 0.226 0.282 0.000
Total
0.080
-
9
required 0.000 0.079 3.283 25.063 0.000 -0,603
-
-
100.00
27.822
SOLID
FOR A
F t . per Lb. of Fuel Burned-In Combustion ProductsHz0 NZ COa 0.000 0.000 0.000 0.000 0.297 0.000 0.000 6.565 12.344 25.063 0.000 94.237 0.000 0.000 0.149 0.000 0.000 -2.267
-
-
-
25.063
6.565
104.760
Total air required: 4.76 X 27.822 = 132.433 cu. ft. HzO brought in b y this air (0.87%) = 1.152 cu. ft. Total flue products = 137.540 cu. ft. H:0 vapor in flue products: 7.717/137.540 X 100 = 5.61. alcd. dew point from Fig. 1 = 96' F.
Total 100.0 0,921 0.473 1.073 3.543 Total air required: 4.76 X 0.921 .= 4.384 cu. ft. HzO brought in by this air (0.87%) = 0.038 cu. f t . Total flue products 5.127 cu. f t . 7 HzO vapor in flue products: 1.111/5.127 X 100 21.67. 8 a l c d . dew point from Fig. 1 = 144' F.
-
1001
-
B
TABLE111. ASALYSES OF TYPECOALS (In per cent by weight. as-received basis) H200
Source
Anthracite Semi-anthracite Bituminous Bituminous Bituminous Bituminous Lignite Lignite, air-dried Peat P e a t air-dried Wooh, air-dried Cannel
Schuylkill Co., Pa. Sullivan Co., Pa. McDowell Co W. Va. Mingo Co. f.' Va. Williamsoi c o . , 111. Moffat Co. Colo. EI Passo cb ~ 0 1 0 . EI Passo cO" ~ 0 1 0 . Fond du a:Co Wis Fond du k a c Co:: Wis:
........
Johnson Co., Ky. Chem. Lab., Rochester Gas a n d Electric Corp.
Coke
0 HIO is given separately b u t is included in the analysis as part of the Hz a n d Oz.
3.33 3.16 2.80 2.44 9.94 18.94 34.40 10.87 76.94 11.99 11.36 2.20 Samples 0.50 3.00 6.94 4.80 13.42 2.91 4.86 2.72 4.18 7.06 10.77 1.98 3.23 2.38 6.95 19.45 18.57 23.52 25.61 29.13
.ish
5:
H2
c
0:
SZ
Samples Listed in I. C. T. ( 2 ) 6.04 9.12 0.60 3.08 81.35 0.79 5.10 1.10 10.17 0.67 3.47 79.49 5.15 1 . 3 5 6.48 0.70 4.57 81.75 8.04 0.95 5.23 77.90 1.54 6.34 1.28 5.35 66.18 1.46 8.84 16.89 6.29 0.64 5.72 57.47 0.82 29.05 0.14 35.94 0.66 42.85 13.89 6.49 0.19 48.83 0.90 18.87 4.81 26.40 0.17 10.87 0.68 3.99 9.63 74.66 15.23 41.49 2.60 34.81 5.23 0.65 0.27 6.62 44.13 0.08 48.92 .... 8.79 10.46 6.58 72.01 1.17 0.99 Taken a t Random from Bureau of Mines Bulletin (7) 0.80 1.25 1;09 9.44 0.97 86.45 0.69 1.48 2.67 83.20 4.48 7.50 0.57 1.29 14.03 2.87 73.40 7.84 3.02 47.10 3.61 38.55 6.95 0.76 0.48 0.81 19.25 3.39 61.55 14.52 3.12 1.17 3.72 17.51 3.60 70.88 0.81 1.93 6.31 3.97 7.32 79.66 4.55 9.41 0.56 1.14 14.36 69.99 8.33 6.27 0.92 4.69 61.88 17.91 1.30 0.61 21.78 4.83 55.14 16.34 0.70 14.87 4.98 55.27 0.61 23.57 1.09 1.08 8.41 4.94 7.85 76.03 0.61 1.42 78.33 6.71 4.99 7.94 1.46 5.29 1.53 4.88 5.16 81.68 8.04 12,19 j .25 1.04 62.74 10.74 0 22 16 38 44.72 0.49 32.40 0 79 5 67 n 57 5.76 53.15 0 95 33.90 , . 4 ? 0 . 8 0 6 02 49.16 0 60 35.90 51.81 35.11 1 11 5.34 0 36 6.2i 48.95 5.82 0.30 6.55 1.03 37.35
Heat Value B.t.u./lb.
HdC
+S
Curve DifRead- fering ence F. F. F.
Dew Point
13,351 13,376 14,261 13,898 11,714 9,722 6,055 8,227 1,879 7,172 7,635 13,748
0.0376 0.0433 0.0554 0.0663 0.0793 0.0984 0.1799 0.0981 0.8723 0.1241 0.1500 0.0901
92 96 101 106 111 118 137 119 179 126 133 114
92 95 101 106 112 119 138 119
12,836 13,500 11,740 6,910 9,895 12,312 13,468 12,461 11,642 9,846 9,641 13,613 14,074 14,487 11,905 7,990 9,391 8,426 9.182 8,401
0.0111 0.0318 0.0388 0,0868 0.0547 0.0486 0.0493 0.0645 0.0688 0.0856 0.0890 0.0641 0.0632 0,0621 0.0742 0.1222 0.1072 0.1203 0 1202 0.1330
67 88 93 114 102 98 99 105 109 114 116 105 105 104 111 125 121 125 124 127
67 88 93 114 101 98 98 106 107 114 115 105 105 104 110 125 121 125 125 128
0 1
0
0 1 1 1
0
...
..
0 1 2
126 132 116
0 0 0 0 1 0 1 1 2 0 1 0 0 0 1 0 0 0 1 1 4
TABLE Iv. .4NlLYSES O F TYPEFCELOILS AS LISTEDIN I. c. T. (3) ( I n per cent b y weight, as-received basis) Source Petroleum oils: Galicis Germany Roumania Russia N. America Mexico S. America India Japan T a r oils: Coke oven Water gas Oil gas Coal-tar oil Domestic: Commercial gasoline Commercial kerosene Paraffin hvdrocarbons: CHI CzHa CIH~ GHio
CsHii CilHis CisHs~ Bansene seripn:
0.8 1.0 0.4 0.3 1.2 2.7 0.6 0.7 0.6
12.3 11.5 11.7 12.1 12.2 12.6 11.7 11.8 11.4
85.i 82.2 86.5 86.8 84.0 79.2 82.4 86.9 87.3
0.6 0.6 0.9 0.7 1.0 1.0 1.2 0.5 0.5
0.4 4.4 0.4 0.0 1.4 4.3 4.0 0.1 0.1
0.88 0.83 0.92 0.92 0.91 0.91 0.92 0.92 0.94
19,440 19,440 18,900 19,080 19,080 18,900 19,080 19,080 18,900
0,1422 0.1382 0.1346 0.1389 0,1432 0.1538 0.1410 0.1347 0,1297
123 123 122 123 124 126 123 122 121
123 123 122 123 124 125 123 122 121
0 0
.. . .
15.7 15.3
84.3 84.6
. ...
0.76 0.82
19,510 18,550
0.1862 0.1802
129 128
129 128
0 0
.... .... .... .... .... ....
25.15 20.13 18 30 17.35 15.89 15.40 15.14
74.85 79.87 81.70
.... .. ... ... ... ... ... .. .. ..
.... .... .... .... ....
.... .... ..... ... .... .... ....
0,3360 0.2520 0,2240 0.2099 0,1889 0.1820 0.1784
140 135 133 131 129 128 128
140 135 133 131 129 129 128
7.75 8.76 9.50
92.25 91.24 90.50
.... .... ....
0.0840 0.0960 0.1050
109 112 116
111 114 116
0.02
...
,..
,..
...
... ... ...
.. .. ..
a
d;:
0.2 0.3 0.1 0.1 0.2 0.3 0.1 0.0 0.1
...
Curye DifferReading ence
0 2
0.4 4.9 0.4 0.0 1.6 4.8 4.5 0.1 0.1
... ...
Dew Point
N2
Sz
... ... ... ...
+C
c
Ash
... ... ... ...
Heat Value B.t.u./lb.
Hi
Ha06
....
.... ,...
....
82.65
84.11 84 60 84 86
... ...
...
H10 is given separately but is included in the analysis as part of the Hz and 0:
. .. ... ...
... ... ... ... ...
... ... ...
.... .
.
I
.
....
.... ....
Hz/S
O F .
O F .
O
F
0 0 0 1 0 0 0
2 2
0
1002
TABLE J.
.ISILYRES O F
I \ D I STtlI\l, i \ D EXGI\EEKIYG CHE\lISTRl \-oL 28, ___T Y P E I S D U i T R I i L FUELGASES PATTERSED AFTER THOSE GIVENI S I. c. T.( 2 , 3) I In
H:n'
€1.
c'o
i:
1,i 1.7
. . .
....
D
1.I
.... .... .... ....
.... ....
1.7 1.7 1.7
50.0
1 7 1.7 1.7 1.i
38.0 55.0
Type
1.1
C
E F
1.7
...
Coke oven:
$C Oil gas
$
Carbureted water I Carbureted water B Blue water C Producer:
2C
Blast furnace
CO1
1.I
1.i 1.7
1.1 1 ,
.., .
10.0 4.0 10.0
24.3 40.0 20.0
........ . . . . . . . . ........
2.0 4.0 2 0
... ...
40.0
. . . . . . . . . . . . . . . .
45.0 50.0
3.0 11.0 28.0 35.0 40.0
6.2 2.8 9.9 2.8
5.1 2.2 3.9
21.0 15.0 6.0
20.0 23.0 23.0
4.0 2 (1 0.4 27 . O
.
45.0
40.0
30.0
1 . ,5
....
....
50 n 20.0
3.1 5.8
4.2 11.0 31.8 10.0 40.0 38.0
.
90 (I 80 (I
....
....
6 5 . (1
'22.0
20.0
5,0 1.0
9 ?
per cent by volume) 5 2
Calcd. Calcd. Heat Dew ValueC Point B. t. u./
, . .
. . . . . . . . . . . .
F.
F. 139 139 138 143 141 133
0
...
139 139 138 137 135 133
3.0 1.0 5.3
8.0 2.3 2'0 . 0
511 704 435
144 142 141
144 143 142
0
2.5 2.0 6.0
6.0 4.5 3.0 3.0 2.3
75g
534 699 396 301
141 145 143 137 140
142 145 143 141 137
1 0 0 4
6.8 6.0 6.0 8.0
46.5 52.3 64.6
173 143 98
129 120 90 133
127 120 9Q 135
0
...
...
. . . . . . . . ,
,.
,
59.3
........ ........
, , , , ,
.
... ...
, ,
...
1.1
1.0 2.0 1.0
...
...
1.5 0.4
. . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
It.
1068 1157 1226 686 915 2202
...
,
Curve DifRead- fering ence
1.0 1.5 1.5 38.3 38.3 1.0
CIL.
S a t u i al:
uo
0
5.0
Paraffin Hydrocarbons Calcd. Curve DifHeat Dew Read- ferGas H?O Gas Value Point ing ence B . 1. u , / cu.f f . F. O F. F. 140 140 0 98.3 997 1.: 1. < 98.3 1751 135 135 0 _".._ 1.7 98.3 2528 133 132 1 C4HlO 98.3 3196 131 131 0 CaHu 98.3 3013 131 131 0 A11 gases were assumed t o be saturated with water a t 60° F.; the dew point C Heat values ( I ) : n t.his case is t h e same as though i t had been calculated on the dry gas only. Gas 6 Illuminants: CzHd CsH6 CsHs B. t. I L .,/ C U . .it. % % % H2 323.5 Coke-oven gas 60 40 CO 323.5 Oil gas 55 45 .. CHI 1014 7 Carbureted wmter zac 65 25 in C:Hs 1781
61.3
2iB
O
F. 0 0 5 6 0
1 1
3
, 0 3
i.:
..
Gas CsHs CzHi C3Hs CBH,
B . t . I L . / C U jl 2572 1631 2336 3741
of the flue products of the theoretical air-gaa mixture, 139" F., is first located by means of the curve for gaseous fuels. The proper curve sloping to the right is then followed until it intersects the vertical from the point representing 6.3 per cent oxygen or 30 per cent air in the flue products, and the dew point of this mixture, 127" F., is read on the dew point scale.
resulting from thib combustion may be roughly estimated froin the heat value of the fuel. The average factors necessary for this calculation are listed in Table VI, together with the approximate accuracy and the exceptions.
Volumes of Theoretical Air Required and
At the dew point only a minute trace of water is condensed. As the flue gas is cooled below this point, however, an increasing fraction of the vapor condenses. This fraction of the total vapor thus condensed may be calculated by the use of Figure 1: Per cent of total vapor condensed at t o = 100 - (curve reading at t"/fraction of water vapor in flue products)
Resulting Flue Products The theoretical quantity of air required for the complete combustion of the fuel and of the volume of the flue products
Condensation of Water from Flue Gases
It is obvious that this formula is applicable only when the whole body of flue gas is brought to a constant temperature.
froni the t o t a l s u l f u r , taken t o he o r i g i n a l l y p r e s e n t in the fuel, by assuming a volume ratio in the flue products of 10 t o 1 for sulfur dioxide to sulfur trioxide. This is t h e a p p r o x i m a t e ratio found in c o r r e s p o n d i n g mixtures by J o h n s t o n e (5) and by M a c o n a c h i e (8). T h e r e s u l t s of these estimations are shown in Figures 3, 4, and 5 for t h e solid, liquid, and gaseous fuels, respectively. A11 of the curves represent the dew points for certain flue gas mixtures only-i. e., 100 per cent excess air for solid fuels and 40 per cent excess air for liquid and g a s e o u s fuels. I n u s i n g t h e s e curves, the t h e o r e ti c a1 dew point for the correct m i x t u r e is first found from Figure 2. The res p e c t i v e curve is then located in Figures 3, 4, or 5 ; its intersection with the vertical p r o j e c t i o n , indicating the sulfur content of the original fuel. is plotted, and the d e x point is read on the left-hcnd side of the chart. In the cases of the solid and liquid fuels where the sulfur is generally given on a weight basis, the horizontal scale is plotted as per cent sulfur by weight; but in the case of the gaseous fuels where the sulfur is generally given as grains per
Actually this is rarely the case in practice. Thus, in economizers, preheaters flue pipes, chimneys, etc., there is a sharp temperat u r e g r a d i e n t near the walls, and condensation or evidence of it by corrosion is often found when the flue temperatures are far above their t h e o r e t i c a 1 dew points (6).
Effect of Sulfur Trioxide on Dew Point
The dew point has been d e h e d as the temperature at which the vapor phase is in equilibrium with a m i n u t e quantity of the liquid phase in any system. In a complex system such as flue gas which contains a large fraction of moisture and a variety of soluble gases, a number of chemical combinations are possible. A survey of the solubility and vapor pressure data for these possible compounds s h o w s , h o w e v e r , that theoretically only sulfuric and nitric a c i d s c o u l d affect the dew point. The effect of nitric acid n-odd be negligible because the vapor pressures of its dilute water aolutions are relatively similar to those for pure water. Sulfur trioxide on the other hand, which is present in appreciable quantities in the flue gases resulting from the combustion of most industrial fuels, forms water solutions, the vapor pressures for which are quite different from those for pure water. For all practical purposes, thereTABLE VI. ESTIMATION OF APPROXIMATE VOLUME OF THEORETICAL AIR fore, the effect upon the dew point of all of the REQTIRED AKD YOLUME OF RESULTISG FLUEPRODT:CTS vapors in flue gases except water and sulfuric acid may be neglected except in so far as they act as inert substances in diluting the vapor volume. Whereas the vapor pressure data for
Cu. Ft./Lb. of Approx. Solid Fuels Accuracy, % Exceptions T1leoretical air required B.t,u, per Ib. o,oo9i 3 1:uels containing Total flue products B.t.u. per lb. X 0.0106 3 i i i o r e th.an Total water in flue products B.t.u. per lb. X 0.0008 50 307'0 water Cu. F t . / L b . of Liquid Fuels Theoretical air required B.t.u. per lb. x 0.0094 3 R e s u l t s l o w for g a s o l i n e and B.t.u. per lb. X 0.0099 3 ~ ~ $ r ~ ~ ~ $ p r o d u B.t.u, c t s per lb. o,oo10 20 kerorene Cu. Ft./Cu. Ft. of Gaseous Fuels Theoretical air required B.t.u. per cu. ft. X 0.0089 (2 a s e s of 300 Total flue products B.t.u. per cu. ft. X 0.0104 a B.t.u. per CU. it. or less 10 ft. X 0.0020 B.t.u. per cu. Total water in flue products
have been accurately determined and are generally available, the necessary Vapor pressure data for dilute sulfuric acid solutions are not, ;$:! and the estimation of the effect of these vapors upon the dew point is uncertain. The calculation is rendered still uncertain when it is found that no completely satisfactory method is available for the accurate estimation of sulfur trioxide in these flue gas mixt'ures. Johnstone (4) has suggested a graphical method, based upon the limited amount of data available, by means of which these dew points might be indicated. By the use of curves such as he has proposed, plotted on a logarithmic scale and extrapolated to the necessary limits, the dew points of certain flue gas mixtures, resulting from the combustion of the various industrial fuels containing various fractions of sulfur, were estimated. A mixture containing 100 per cent excess air was chosen for solid fuels, whereas mixtures containing 40 per cent excess air were taken for liquid and gaseous fuels. The sulfur trioxide in these flue gas mixtures was estimated
100 cubic feet, this figure was first divided by the B. t. u. of the gas per cubic foot and then multiplied by 100, and this latter figure was plotted on the horizontal scale. All of these curves were calculated from the analyses of the various fuels shown in Tables 111, IV, and V by means of a chart corresponding to that given by Johnstone (4), and the curves are included merely to indicate the probable effect of traces of sulfur trioxide upon the dew points. I n the case of the solid fuels, a certain amount of the total sulfur originally present in the fuel is found in the ash. Johnstone ( 5 ) st'at'es that this may vary from 10 to 30 per 1003
INDUSTRIAL 4UD ENGINEERING CHEMISTRY
1004
cent. A correction for this factor may first be applied, and the dew point can then be estimated from the remainder; Obviously, the deviation from the theoretical dew point by reason of the presence of sulfur trioxide in the flue gas must be recognized or the dew point calculation is valueless. Only a small number of actual dew point determinations have been made (4, 6, 8, 9 ) , but they check well with the results indicated by these charts. No account can be taken in such a calculation for the catalytic effect of certain dusts and metallic salts in the flues upon the oxidation of sulfur dioxide to sulfur trioxide or of the effect of hygroscopic salts (6), but these factors must be kept in mind in the application of calculated dew point data in practice.
VOL. 28, NO. 9
Literature Cited (1) Am. Gas Assoc., “Combustion,” 3rd ed., 1932. (2) International Critical Tables, Vol. 11, p. 131, New York, McGraw-Hill Book Co., 1927. (3) Ibid., Vol. 11, p. 159. (4) Johnstone, H. F., Univ. Ill. Eng. Expt. Sta., Circ. 20 (1929). (5) Ibid., Bull. 228 (1931). (6) Keenan, J. H., Steam Tables, Am. SOC.Mech. Engrs., 1930. (7) Lord, N. W., and Others, U. S. Bur. Mines, Bull. 22 (1913). (8) Maconachie, J. E., “Deterioration of Domestic Chimneys,” Toronto, Consumers Gas Co., 1932. (9) Teaw, J. S., and Shnidman, L., IND.ENG.CHEM.,27, 1476 (1935). RECEIVED April 15, 1936.
CARNAUBA WAX An Expedition to Its Source J. VERNON STEINLE, S. C. Johnson & Son, Inc., Racine, Wis.
@T
HE general lack of knowledge of the production of many industrial raw materials, originating in remote corners of the world, is sometimes appalling to the scientist. Carnauba wax, of w h i c h a b o u t h 8 0 0 tons of an annual production of over 10,0001 tons are imported into the United States, is a typical example of a raw material, very , important to certain industries, of w h i c h t h e lack of first-hand information of the source and processing has been outstanding. This wax is used in the manufacture of p o l i s h e s f o r floors, automobiles, f u r n i t u r e , shoes, etc.; in candles to raise the melting point; in carbon paper; and in a variety of molded products. Articles published by scientific men in technical and trade papers reveal a curious lack of accurate information about this wax in any stage of its production or in any form other than that in which it appears on the market. With the purpose of investigati n g t h e source of carnauba wax and studying its production, an expedition was organized by S. C. Johnson & Son, Inc., last fall to visit the carnauba co:untry of northeastern Brazil and to study more closely the growth, harvesting, and recovery of this important raw material. In order to reach quickly the remote parts of t h e country where carnauba wax is produced, an airplane expedition was planned. The party, including pilots and the w r i t e r , c o n sisted of six members led by H. F. Johnson, Jr. The airplane was 1 Entimates of Department of Agriculture of Brazil for 1935.
an S-38, two-motor, Sikorsky amphibian equipped with facilities for two-way radio communication. The PanAmerican Airways were of great assistance and the facilities of their organization were used wherever available.
UNCUT CARSAUB.4 P.4LM I S FCLLFOLIAQE; THISSPECIMEN IS ABOUT 25 TO 30 k7EARS OLD
AN
Preparations Months were given to careful planning and preparation for the flight. All available literature from the Department of Agriculture of Brazil and from other sources was gathered and studied to determine t h e e x a c t location of the known stands of carnauba p a l m t r e e s . From t h i s accumulated information, a composite map was prepared and the city of Fortaleza in the State of Cearit was selected as a base for operations. F r o m t h i s city, routes to the various centers of production were planned. Preparations were then made for gasoline supplies a t various strategic points along the coast of South America and a t numerous inland towns. Since we were contemplating a trip into territory which is sparsely inhabited, and our means of transportation was such that we might be forced to spend considerable time in a wild and barren country, all of the usual paraphernalia of an expedition into such country were shipped to Fortaleza. Firearms, a m m u n i t io n , auxiliary food supplies, camping and traveling equipment, and medical supplies, as well as scientific and laboratory supplies and complete photographic equipment, were sent. Preliminary test flights were made wit,h our plane carrying complete e q u i p m e n t and personnel. All safety devices were tested, and the
