718
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
Storage tests of bagged material for 6 to 12 months under factory conditions are recommended for final evaluation of t h e storage properties of ammonium nitrate fertilizer. For material t o be applied directly, d a t i v e drillability as determined in the present work is believed t o be a useful guide. Laboratory determinations of rate of moisture absorption, in small samples of conditioned ammonium nitrate, are of limited significance in intlicating the'potential value of the conditioning treatment used ACKNOULEDGMENT
The authors are indebted to .I.31. AIiller, R.I;.Copson, J. H. Waltliall, a n d ' s . A. Harvey for helpful criticism, advice, and encouragement. hcknoivledgment is made t o J. E. Chenevey, W. L. narrow, J. Stalcy, H . J. Strauss, D. E. Bordelon, and S. P. Clark, d l of wliorn participated i n the experimental work.
Vol. 38, No. 7
LITERATURE C I T E D
Cairns, It. W., G. S.Patent 2,211.738 (1940). Chenevey, J. E., Chem. R. N e t . Eng., 52, No. 8, 115 (1945). I b i d . , 20, N o . 1, 8-17 (1919). (3) Fairlie, Ai.W., (4) Gardner, H. A , , "Phy.?ical and Chemical Examination of Paints, Varnishes, Lacquer and Colors", 7th ed., pp. 541-5, Washingt o n , Inst. of Paint and \-arnish Research, 1935. 31, 903-8 (1939). (5) Kc,enen. F. G . , ISD.ESC. CHEM., Chem. & M e t . E ~ Q . , (6) Kmse, H. J., l-ee. J . Y.. and Braham, J. M., 32, KO. 2, 241-3 (1925). ( 7 ) t l o s s , W. H . , Adanib, J. H.. Yee, J. Y . , and Whittaker, C. IT,, I s m ENO.CHEM.,36,1088-95 (1944). ( 8 ) Roy;;, \I7, H., and Tee, J. Y., A m . Fertilizer, 102, No. 7 (;ipril 7, 1945). (9) Titlestad, N.ii., I b i d . , 101, X o . 10, 9 (1944). (10) War Production Board. Chemicals Div., private commuiiication, .4pril 26, 1943. (1) (2)
Uncatalvzed Reaction of Natural Gas and Steam J
.ALVIN S. GORDON Central Experiment Station, U . S . Bureau of Mines, Pittsburgh, P a .
T h e uncatalyzed reaction of natural gas with steam has been studied between 1225' and 1516" C. with steamnatural gas ratios of 1.5 and 5, and time of contact between 0.21 and 4.6 seconds. Even at high temperatures, long contact times, and steam-natural gas ratio of 5 there is some carbonization of the natural gas. The extent of carbonization is shown to be a fuiiction of the ratio of steam to natural gas, and to Fary erratically with temperature and time of contact. As the temperature is increased, the percentages of natural gas undecomposed in one pass through the furnace become less dependent on contact time (in the range of contact times studied), until at about 1500"C. there is little or no effect. At any tempeiature the percentage of undecomposed gas shows little if any dependence on the ratio of steam to natural gas
T
HE catalyzed reaction bc.tn.een steam and natural gas has
been studied by a number of investigators (1, Z), and industrial processes arc>being used t o produce a mixture of hydrogen and carbon monoxide by this reaction a t 750' t o 900" C. Sickel seems to be the best cata1y.t; it i,? usually supported on some refractory with a promoter wcli a i magnesium oxidr, aluminum oxide, or chromium oxide. Cheap and efficient heat transfer in gas systems, obtainable by the use of pebble furnaces, furnishes a n attractive industrial posgibility for carrying out the uncatalyzed natural gas-steam reaction. Temperatures u p to 1500' C , may be used with Alundum pebbles. The uncatalyzed reaction has been studied by Karzhavin (3) who states: "The rate of reaction of methane with steam is very low mid only at temperatures above 1300" C. does it become sufficiently high for industrial use." K O data are supplied t o support this statement. T o obtain d a t a which can btl used for design of pilot plant installations, a laboratory investigation of this reaction at high temperatures was undertaken, and the reaction conditions w r r e limited to those significant for iritlustrial conditions. Figure 1 is a sch(.matic drawing of the apparatus. S a t u r a l gas i.\ admitted to the system through flowmerer A , and then goes iiito wattir saturator R , which consists of a glass distilling flaqk
with a heating coil resting inside and a t the bottom of the bull, The current t o the coil is controlled by a variable voltage transformer (T'ariac). T h e gas is admitted to the base of the asbestos lagged column, Khich is packed with a tightly rolled coil of stainless steel screening t o increase the contact' surface of water with gas. From temperatures read on a thermometer placerl with thc bulb a t the height of the exit tube, the water vapor pressure of the reactant gases is determined. The total pressure is one atmosphere. The difference between atmospheric pressure arid the vapor pressure of the water gives the pressure of the natural gas. In operation the exit temperature is controlled by the current supplied t o the heating coil. T h e saturator is similar to the one used by Hawk, Golden, Storch, and Fieldner ( I ) . The degree of saturation of the gas by water vapor was determined by trapping a known volume of the natural gas-steam mixture in a boiling-water thermostat, displacing the water vapor into a drying tube, and determining its weight. This method rhoiwd t h a t the gas was s a h r a t e d with water vapor nrithinexperimental error, even at the highest flow rates of natural gas u ~ r t i in this research. Some of the data are included in Table I . The flow rates of the gase* were incawTed lvith a capillary flolvmeter.
nllip. Bt
llxi: Tuhe. C. 85 ti 85 8 85 8 94 2 94.2
'pornl I'ressurr. AIni.
lqou.R~~~ of Nntural (>ah, r c . :set.
740 743 745 739 739
1 14 1 30 1 30
1 23 1 18
Ratio, Steitrn/Natural Gas lheoretical Observed 1.50 1.4i 1,50 1 20 1 50 1.25 5.00 4 31 5 00 5 3:
From the saturator t h r gases are let1 into the reaction vessel through tubing heated by resistanw wire. I n the earliest experiments this vessel was quartz, with quartz-Pyrex graded seals in the cold portion at each m d . Quartz \vas not used because i t devitrifiw rapidly at temperatures o w r 1000" C. and is permeable to hydrogen : consequc~ntlya porcelain brssel \vas substi-
July, 1946
INDUSTRIAL AND ENGINEERING CHEMISTRY
oxide and carbon tiioxidc content of the exit, gas. From the equation of tlic reaction with steam, the percentage hydrogen may be readily calculated if no carbon is formed. I t T a s assumed that all the hydrocarbon gascs reacted in'the same ratio as their percentage composition in the original gas. This introduces a small error in tlic result
