Mar.,
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
1920
folded and used in funnels in t h e same manner as filter papers. Alundum crucibles were used for t h e alkaline filtration. T h e apparatus can also be used as a reflux condenser in organic preparations. Credit should also be given t o Miss Vanna Elliott a n d Mr. Guy G. Frary for aid and helpful suggestions.
289
remove most of this and collected in a gas holder over water. The amount of ammonia in t h e scrubbed gas is ordinarily about 0.04 per cent. TS T I N OR B R A Z E JOINTS
H)hlD
5 I N G COIL
PURIFICATION OF COMPRESSED GASES IN TESTING CATALYSTS FOR AMMONIA SYNTHESIS By R. 0. E. Davis BUREAUO F SOILS, DEPARTMENT O F AGRICULTURE, WASHINGTON, D. C. Received October 2, 1919
T h e method of purification of gases described below is t h e one used in testing catalysts a t t h e Arlington, Virginia, plant in work on t h e synthesis of ammonia carried on in cooperation between t h e Bureau of Soils, U. S. Department of Agriculture, and t h e Nitrate Division of t h e War Department. I wish t o acknowledge especially t h e services of C a p t a h P. E . Landolt in offering suggestions as t o t h e arrangement and installation of t h e purification set.
NICHROME GAUZE HEATING COIL PACKED IN ALUNDUM CEM ALUNDUM TUBE
PALLADIUM ASBESTOS
NICHROME GAUZE
FIG. 2-PALLADIUM
SOOA LIME, 10-20 MESH
$'LAYER STEEL WOOL TIGHTLY PACKED
1
I I
SODA LIME, 10-20 MESH STEEL OR G U S S WOOL TIGHTLY PACKED ICHROME. GAUZE
FIG. ~-PURIPICATION CHAMBER, SHOWING CONNECTIONS AND MANNER OF PACKING P R E P A R A T I O N OF GAS-The gases, hydrogen and nitrogen, used for testing catalysts as t o their power t o act in ammonia synthesis need t o be as pure as possible in order t o test t h e catalyst under favorable conditions. The source of gas used is liquid ammonia, decomposed by iron catalyst a t 675' C. This gives a fairly pure gas b u t impurities are sometimes present. For instance, amines are known t o be present, with occasional traces of carbon monoxide and sometimes sulfur. The hydrogen and nitrogen formed by decomposition b y heat still carry a small amount of ammonia and are, therefore, scrubbed with water t o 1
Published byypermission of Chief of Ordnance.
CHAMBER, SHOWING CONNECTIONS, CONSTRUCTION O F HEATER,AND PYROMETER WELL
The gases in t h e gas holder in t h e proportion of one part of nitrogen t o three of hydrogen may contain traces of CO. some COz, a n d oxygen and water vapor derived mainly from their contact with water. T h e presence of CO is rare. Carbon dioxide may be present b u t is not so undesirable as t h e others. Ammonia sometimes is as high as a few hundredths per cent. Oxygen is present in about 0 . 0 2 and 0.03 per cent and sometimes considerably higher. Water, of course, is present t o t h e point of saturation a t t h e temperature of t h e gases. On compression t h e water is partly removed, some of i t condensing in t h e compressor cylinders, b u t t h e gases passing from t h e compressor a t I O O atmospheres still carry water a n d t h e other impurities. Oxygen and water are both extremely poisonous t o some catalysts. PURIFICATION O F GAS-The compressed gases pass through a system of seven chambers for t h e removal of these impurities. These chambers are steel cylinders (Fig. I ) 2 4 in. long, 33/4 in. inside diameter, with a/4 in. wall, and have flanged ends for closing. The heads are made gas-tight by use of copper gaskets, and t h e blind flange carries ridged rings whiCh fit into corresponding grooves in t h e end of t h e cylinder. These cylinders have t h e inlets at t h e bottom and t h e outlets at t h e top. The system is made up of a steel wool filter for catching oil and water spray, a palladium chamber for removal of oxygen, a water trap, another steel wool filter, 2 soda lime and calcium chloride chambers, used alternately t o allow refilling for removal of water a n d carbon dioxide and ammonia, a ohosphorus pentoxide chamber and a sodamide chamber I
_
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
FIQ.3-APPARATUS
U S E D FOR
ANALYZINC GASESFOR
o r removal of final traces of moisture and carbon monoxide. The palladium chamber'is arranged differently from t h e others (Fig. 2 ) i n t h a t i t is supplied with electric heat. T h e central steel t u b e attached t o t h e head is filled with steel wool mixed with 5 per cent palladinized asbestos. This fits into a n alundum t u b e wrapped with nichrome resistance wire. T h e gases enter at t h e t o p , flow over t h e outside of t h e heater a n d u p through t h e central t u b e , coming i n contact with t h e palladium,, where t h e oxygen is converted t o water. T h e temperature is maintained a t 300' t o 400' C. T h e gases are in this t u b e ordinarily from 1 2 sec. t o 2 min., depending on t h e r a t e of circulation of t h e gases. T h e sodamide chamber is heated b y a n external winding t o slightly over 100' C. Carbon monoxide reacts with sodamide as follows: 2NaNHz CO ----f CHI Na20 NZ a n d with hydrogen sulfide according t o t h e reaction
+
+
+
Vol.
12,
No. 3
OXYGEN AND &fOISTURE
+
+
2NaNHz HzS -+ NazS 2NH3. GAS-After t h e gases pass through this t r a i n t h e y are carried t o t h e catalyst chambers. A valve i n t h e gas line allows of t h e sampling of t h e gases for analysis. A slow flow of t h e gas, about 50 cu. f t . (Fig. 3) per day, from this valve passes through a t r a i n consisting of a glass wool filter, phosphorus pentoxide t u b e for removal of water, pverheated palladium asbestos for removal of oxygen, through another phosphorus pentoxide t u b e t o catch t h e water formed, two guard tubes of P205 a n d soda lime, and t o a gas meter. T h e PnOs tubes are removed and weighed every 8 hrs. a n d t h e amounts of water a n d oxygen i n t h e gas determined. At t h e suggestion of C a p t . H. A. Curtis, t h e quartz t u b e was replaced b y a glass one with t h e stopcocks sealed on t o eliminate t h e danger of burning the rubber stoppers used with t h e q u a r t z tube. Percentages of oxygen a n d of water run in t h e order of 0.001per cent a n d 0.0001per cent, respectively. ANALYSIS OF
ADDRESSES AND CONTRIBUTED ARTICLES POTASSIUM NITRATE FROM THE CHILEAN NITRATE INDUSTRY By P. F. Holstein
The industry a t the present time seems to be in rather a receptive mood as regards development of new methods, as is evidenced by numerous experimental plants, and it is very probthat the next few years see the production Of potassium ASSISTANTADMINISTRATOR, O~ICINA D&LAWARB, DU PONTNITRATE COMkitrate in increasing quantities from the pampas of Chile. This PANY, TALTAL, CHILE article aims t o present some of the main facts of the situation Received October 1, 1919 Most of the information published regarding the possibilities and t o describe briefly the means actually a t hand by which of the production of potash in the Chilean Nitrate "Oficinas" and the present status of the question has been entirely general in character and a t times misleading. The importance of this source of supply has been appreciated indeed by only very few of the nitrate producers themselves, yet during the war and a t the present time several Oficinas (not more than half a dozen in all) manufactured a grade of nitrate containing a high percentage of potassium nitrate. Oficina Delaware of the du Pont Nitrate Company, a subsidiary of E. I. du Pont de Nemours and Company, has been the pioneer in this new development, which bids fair to be a factor of considerable value both to the nitrate producer and the potash consumer.
potash may be recovered. During the year ending June 30, 1918, there were produced in Chile 64,340,267 quintals of nitrate (one quintal = 101.4 lbs.) or over six and a half billion pounds. The average potassium nitrate content of all the nitrate shipped is probably about 2 per cent, so that there were contained in this nitrate about 130,000,000lbs. of potassium nitrate for which the producer received no additional profit. Calculated on a basis of KzO this represents 30,000 tons of potash or about 2 I per cent of the total consumption of the United 'States. That this potash may be separated successfully and sold as a distinct product there is not the least doubt. This has been done
