INDUSTRIAL A N D ENGINEERING CHEMISTRY
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Vol. 23, No. 3
A Useful Horizontal Tank Chart’ W. F. Schaphorst 45 ACADEMYST.,NEWARK, N. 1
HE accompanying chart gives the number of gallons of liquid in any horizontal tank without the use of tables, formulas, figures, or computations of any kind. Simply start at the left and zigzag a ruler or thread across the chart three times as demonstrated by the dotted line and the number of gallons is immediately found in column G.
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For example: How many gallons in a tank 84 inches in diameter, the depth of liquid being 30 inches and the length of the tank 142 inches? 1 Received
January 22, 1931.
Run a straight line through the%4 in column A and the 30 in column B and locate the intersection with column C. Follow the radiating guide lines t o column D, locating a second point of intersection. From this intersection run through the 142, column E , and locate the point of intersection in column F. Then from this point run over t o the 84 column H , and the intersection in column G will be found to be close t o 1050 gallons, which is the ansffer.
To make the chart absolutely clear sketches show the diameter of the tank, D, the depth of liquid, h, and the length
March, 1931
INDUSTRIAL AND ENGINEERING CHEMISTRY
of tank, L , with wavy arrows leading from them to the proper columns. This chart takes care of any depth of liquid from 0.1 inch to the full capacity of‘ the tank, any diameter from 2 to 200 inches. and any length of tank from 10 to 100,000 inches. It will give an answer much more quickly than tables or formulas. I t is surprisingly accurate. It is more complete than tables because it takes care of every dimension between
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2 to 200 inches, whereas tables generally skip many diameters and lengths. Since column E takes care of lengths of tanks up to 100,000 inches, this chart can also be used to compute either the full or the partial capacity of long pipes. Inversely the chart may be used for determining the length of tank necessary to hold a given number of gallons where the diameter of tank and depth of liquid are known or fixed quantities.
Destructive Hydrogenation in Bomb-Polymerization in Cracking’ Stephen A. Kiss STANDARD OIL DEVELOPYENT COMPANY, 26 BROADWAY, NEW Y O R KN. , Y.
The initial retardation of the decomposition in deyields is given in Table I of H E mechanism of the structive hydrogenation runs, carried out in a closed the present paper. It will cracking reaction has bomb, has been explained by the Poynting effect, which be recalled that in the attracted attention in abstracts the ‘,activated molecules” from the liquid straight cracking experiments recent years. In 1926 Leslie phase and transforms them into “non-activated molethe observed residue values, and Potthoff (4)discussed the cules.” Formula 13 for the kerosene yield and 14 10.2 and 6.7 per cent in the 2validity of the law of monofor the gas and gas-plus-gasoline yields in such runs and 4-hour runs, respectively, molecular reaction velocity have been developed. were c o n s i d e r a b l y higher for cracking and gave an apPolymerization in cracking has been discussed a t than the c a l c u l a t e d ones. proximative formula for the some length, with the consequent deduction of ForAdding to the last observed calculation of distillate yields. mula 15 for the amount of polymerization products. residue values 0.3 and 4 per Pease (6) in 1928 considered Finally, attention has been directed to the desirability cent of coke, r e s p e c t i v e l y , cracking as monomolecular of carrying out experiments with the express a i m of purthe actual values of heavy decomposition. Hurd suing a more detailed study of polymerization. products in these two crackand Spence ( I ) c r a c k e d ing runs became 10.5 and 10.7 isobutvlene vaDors and calculated the totai decomposition by the integrated form of the per cent, as compared to the calculated values of 7.1 and 0.5 law of monomolecular reaction velocity (1929). The writer per cent, respectively. This difference, still more pronounced (2) in 1930 developed formulas for calculating the yield of in the case of poor charging stock, must be attributed to three typical cases of monomolecular decomposition and polymerization, which is characteristic of cracking reactions applied the same t o the experiments of Waterman and Perquin and is the underlying cause of one of the major problems of commercial cracking operations, the coke formation. In (9) described in 1925. Table I we see that during hydrogenation under high pressure Study of Results of Waterman and Perquin no polymerization takes place and the following two definiThe present effort is concerned with the interpretation of tions seem to be justified: the results obtained by these investigators in their hydrogena(1) Cracking is a monomolecular decomposition charactertion experiments. In their runs 200 grams of Rangoon paraf- ized by polymerization. fin wax were charged in a bomb and hydrogen was admitted (2). Destructive hydrogenation is a monomolecular decomuntil the pressure reached 110 atmospheres. The bomb was position in which no polymerization takes place. then closed, the charge heated a t 450’ C. for a predetermined Explanation of Retardation of Decomposition length of time, and the products were analyzed. The retardation of decomposition in the short hydrogenaRaterman and I’erquin noted that the decomposition in the hydrogenation runs lasting less than an hour was much tion runs in a closed bomb may be explained in the following less than during the corresponding cracking runs. In the manner: I n a heated fluid (liquid or vapor) the kinetic I-, 2-, and 4-hour runs there was no such retardation of the energy of the molecules varies according to Maxwell’s law decomposition during hydrogenation. This pecu1i:tr behavior of distribution, a small percentage having a very high kinetic will be explained later. For the present let us assume that energy and velocity. It is precisely these molecules which the decomposition in hydrogenation follows the law of mono- undergo cracking because their intra-molecular bond breaks molecular reaction velocity, so that Formula 3 of 1he writer’s on collision. Most of the paraffin wax will be in the liquid phase a t the previous article ( 2 ) is available, together with the value of temperature of the Waterman and Perquin experiments (450 O = 0.02173 of Table I, for the calculation the cracking rate of the residue. However, since the extent of retardation of C.). However, there will be a considerable difference in the decomposition in the short runs is unknown to us a t the vapor pressure of the liquid paraffin wax in the straight crackmoment, we shall use Formula 3 for calculating the “equiva- ing runs and in the hydrogenation runs because of the therlent time”-that is, the time necessary to obtain the experi- modynamical law that the vapor pressure of liquids in an mentally observed residue yield in unretarded decomposition. atmosphere of indifferent gas is greater than in vacuo. AcThe long runs will be calculated on the basis of the actual cording to this law, usually known under the name of “Poynting effect” (7), the following relationship exists between the duration of the experiments. The comparison of the experimental and observed residue vapor pressure, p , the pressure of the indifferent gas, P , the molar volume, v , of vapor and the molar volume, V , of liquid 1 Received December 29, 1930.
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