Apparatus for producing hydrocarbon slurry containing small particles of magnesium for use as jet aircraft fue

Prok, G. M.

Walsh, T. J.

Witzke, W. R.

English

NASA Technical Reports Server

April 26, 1960 T. J. WALSH ET AL 2,934,33 1 
APPARATUS FOR MAKING A METAL SLURRY PRODUCT 
Filed Deo. 22, 1955 2 Sheets-Sheet 1 
-- - 
"' 
e4 
0 
-0 (ACCESSION NUMBER) 
5 
INVENTORS 
THOMAS J. WALSH 
WALTER R W/TZKE 
5 J L' 
Y (PAGES) (CODE) 
t 
- / 
( N ~ S ~ C R  OR TMX OR AD NUMBER) 
15 
(CATEGORY) 
https://ntrs.nasa.gov/search.jsp?R=19700024071 2020-03-17T01:33:23+00:00Z
April 26, 1960 T. J. WALSH ETAL 2,934,33 1 
APPARATUS FOR MAKING A METAL SLURRY PRODUCT 
Filed Deo. 22, 1955 2 Sheets-Sheet 2 
F I G  4 
BY 
2,934,331 United States Patent Office , Apr. 26, 1960 
2 
provide access to the furnace interior. The entire furnace 
with the connecting tube and nozzle is covered with ar? 
. . 
APPARATUS A METAL SLURRY asbestos insulation iayer 17 and heat is supplied the fur- 
PRODUCT nace by induction coils 18 and 19 surrounding, respec. 6 tivefy, both furnace and outlet tube. The coils are con- 
Thomas 3. Walsh and Walter R. Witzke, Cleveland, and nected to a 30-kilowatt high-frequency electric source 20 
George M. Prok, Avon Lake, Ohio, assignors, by mesne through switch 21. 
assignments, to the United States of America as rep- Opening 14 of tube 12 is connected to a source of inert 
resented by the Administrator of the National Aero- gas, such as helium, so as to provide, at will, a purging 
nautics and Space Administration PO means for removal of oxygen from the entire unit and 
Application December 22, 1955, Serial No. 554,899 also, to permit operation of the unit under conditions of 
inert pressure, a value of 3.5 pounds per square inch being 
3 Claims. (Cl. 266-19) satisfactory flowing at a rate up to 23.7 pounds per hour. 
(Granted under Title 35, U.S. Code (1952), see. 266) Without this pressure and, particularly, a t  sub-atmos- 
16 pheric pressures, the operation of the system results in 
The invention described herein may be manufactured particles having low free-metal content. This is assumed 
and used by or for the Government of the United States to be due to oxidation of the magnesium by air leaking 
of America for governmental purposes without the pay- into the apparatus, since on raising the pressure above 
ment of any royalties thereon or therefor. atmospheric, high product purity is obtained. Preferably 
This invention relates generally to the manufacture of 20 the helium is preheated prior to passage into the furnace 
extremely sinall metal particles especially in the form of by passage through an Inconel resistance coil 30 in series 
metal-hydrocarbon slurries, and more particularly to ap- with the pipe line to the helium source. The coil 30 is 
paratus for producing a hydrocarbon slurry containing provided with end terminals 31 and 32 which are con- 
extremely small particles of magnesium. nected through switch 33 to a 300 ampere direct current 
The preparation and use of metal slurries for various 25 Power supply 34, such as used in welding equipment. A 
purposes are well known. However, the use of metal gas preheat in excess of the melting temperature of mag- 
slurries for fuel in aircraft, particularly jet planes, has nesium is required, that is, in excess of 1202" F., tem. 
been attended with some important difficulties, such as Peratures up to 1700" F. being usable, and temperatures 
improper flow and inadequate stability, arising largely below 1202" F. resulting in considerable, and in some 
from the oversize dimensions and improper shape of the cases, complete clogging of the flow line. 
metal particles, as produced by ordinary methods. The outlet tube 13 of the furnace opens directly into 
The objects of the invention include the provision of the shock cooling condenser 40. This condenser consists 
a process for preparing metal slurries in which the size of of an elongated chamber with a horizontal top and a base 
the metal particles is reduced to the upper limit of the section inclined downwardly from the furnace forming 
colloidal range; the provision of a metal slurry-making 35 larger and smaller ends, the smaller end 41 being attached 
process in which the use of mechanical disintegration to tube 13, in extsnsion thereof, and the larger end 42 
process steps are eliminated; the provision of a metal being provided at its base with a funnel shaped outlet 43. 
vapor condensation process in which the coolant forms The top of the chamber is formed into a series of recesses, 
part of the slurry product; the provision of a metal slurry t h e e  as shown numbered 44, 45 and 46, respectively, in 
process in which clogging in the flow lines is largely elimi- 40 each of which is placed a single spray nozzle. These 
nated; the provision of a metal slurry process in which im- nozzles are of the hollow cone type, nozzle 47 preferably 
purities in the metal particles are effectively removed; the being rated at 10.5 gallons Per hour with a 60' spray 
provision, in a metal slurry, of particles which have an angle, and the other nozzles 48 and 49 preferably being 
average equivalent spherical diameter less than 2 microns rated at 21.5 gallons Per hour with an 80' 8Pray angle. 
and which have a purity ranging as high as 98.0% by 45 Nozzle 47 with the narrowest spray angle is placed near- 
weight free metal. est the smaller end 41 of the condenser 40 to minimize the 
Other objects and many of the attendant advantages of cooling of the furnace outlet tube 13 by the liquid spray. 
this invention will be readily appreciated as the same be- This condenser arrangement provides a curtain of coolant 
comes better understood by reference to the following de- in the path of the hot metal laden vapor flowing through 
tailed description when considered in connection with the 60 outlet tube 13 of vaporizing furnace 10. Each spray 
accompanying drawings wherein: nozzle is connected through a valve 50 to a source of con- 
Fig. 1 is a view, partly in section, showing the schematic densing medium, which for fuel uses, should preferably 
arrangement of the apparatus used in the slurry making be a hydrocarbon. Aircraft engine fuel, with an end 
process; point not over 300" C., a viscosity not exceeding 10.0 
Fig. 2 is a view of a modified vaporization pot; 55 centistokes at -40' C. and a specific gravity not greater 
Fig. 3 is a diagram of size distribution of the metal than 0.850 at 15.6l15.6' C .  gives satisfactory perform- 
particles from a typical run; and ance. 
Fig. 4 is a copy of an electron micrograph of a rep- The furnace outlet tube 13, which feeds into the con- 
resentative field of magnesium particles obtained by the denser 40 is preferably modified as a nozzle 51, extending 
instant process. BO outwardly from the furnace chamber and provided with 
~ ~ f ~ ~ ~ i ~ ~  now more particularly to the drawings a contour insert 52 within the tube. This insert is made 
\herein like reference characters designate identical or of stainless steel and is of the Ventuii type with a rounded 
similar parts througllout the several views, and more par- co"ve~ing surface at the furnace end and uniformly di- 
ticularly to Fig. 1 thereof whereon apparatus for obtain- verging surface approaching the condenser end, the point 
of maximum constriction being near the furnace end. iiig siliiable iiieial sliiiiies is showii as iilcludiilg a vapor- To separate thet metal particles from the inert gas, izing furnace 10 consisting of an upright cylindrical cas. the unvaporized hydrocarbon and part of the condensed ing 'lased at the base and provided at the with magnesium particles are passed into a 20 gallon collector 
an inlet tube 12 and at the side adjacent the top with a tank 53 positioned below the condenser 40 and connected lateral outlet tube 13. The tube 12 terminates in a T to the outlet 43 of the condenser by tube sections 54 and 
structure having opposed side openings 14 and 15 and a 55. This tank is provided with a depth gauge consisting 
screw-threaded end plug 16 which may be removed to of an external, transparent tube 56 connected to the tank 
2,984,882 
3 a 
at the top and bottom, as shown, to secure liquid depth receiver "7 are now pumped through a 100-mesh screen, 
measurement. not shown, to remove any coarse particles and thorongh- 
At the junction of tube sections 54 and 55 between the ly mixed with a turbine stirrer not shown, samples of the 
condenser and tank 53, a tube 57 leads to the cooling product being taken for analysis. While the slurry thus 
unit 58, which may be in the form as illustrated consist- 5 formed may be used without further treatment, it is 
ing of a flat shaped drum 59 adapted to be fiiled with ice- usually desirable to concentrate the mix from a 0.5 per- 
water, and containing cooling coils for condensation of cent solids value to about a 50 percent value, use being 
the hydrocarbon vapors not condensed by condenser 40 made of a bowl-type centrifuge, not shown, at  a feed 
or retained by the collector tank 53. These coils may rate of about 500 cubic centimeters per minute to form 
take the form of helically wound layers of tubes 60 con- 10 an extremely viscous, clay-like mass which, when sliced, 
nected at their inner ends to a vertical manifold 61 in has a metallic luster similar to sodium metal. From this 
prolongation of tube 57, inside the drum. The outer ends mass, by the addition of an appropriate surface-active 
of these coils are connected to  maxifold 62 and the mani- agent such as 1.3 percent by weight of a glycerol sorbitan 
fold 62 feeds downwardly from the tank by tube 63 into laurate, a pumpable slurry fuel is produced, this agent 
a second collecting tank 64 also provided with a depth 15 lowering the viscosity of the mass to between 5,000 and 
gauge 65. 10,000 centipoises. 
As a further precaution in preventing loss of metal The 100-mesh screen serves as a measure of the effi- 
particles the inert gas is led from tank 64 to a point ad- ciency of the condensation process, this size screen being jacent the base of a third tank 68 by means of tube 69, selected since the openings therein are smaller than those 
which enters tank 68 through the closed top thereof, as 20 of any orifice which might be used in a fuel system and 
shown. This tank is about half filled with a hydrocarbon therefore precludes any future stoppage of slurry fuel 
liquid 79 and the inert gas is made to bubble through this flow. The amount of fine particles of magnesium passing 
liquid to  enforce particle deposition. The gas is then through the screen ranged from 85.0 to 99.7 percent, on 
led by tube 71 through a felt filter 72, by a condensate a weight basis, the average running close t o  95.0 percent 
receiver 73 through valve 74, through a water-cooled heat 25 by weight. The particle-size distribution of the metal 
exchanger 75, provided with water connections 76 and 77, particles was determined by centrifugal sedimentation 
and by a bleed valve 78 to the vacuum pump line 79. analysis, and for a typical run, was found to indicate that 
At appropriate points, measuring instruments, in addi- 33 percent by weight of the particles are finer than 1 
tion to the liquid gauges of tanks 53 and 64, are em- micron in equivalent spherical diameter and 73 percent 
ployed to insure efficient operation of the unit. For ex- 30 by weight finer than 2 microns. This relationship is 
ample, at opening 1 5  of furnace inlet tube 12, a duct shown in Fig. 3 of the drawings by curve 85. 
82 connects the inflowing gas to a pressure recorder of The shape and size of the solid-metal particles obtained 
conventional type, also thermocouple wells 83 for the from the magnesium vapor condensation is best observed 
liquid and 84 for the gas, are inserted in the furnace by means of electron micrographs of the product. Fig. 4, 
chamber and thernlocouple connection 15 made to aP- 35 which is a copy of a micrograph enlarged 25,000 times, 
propriate temperature reading instruments. A thermo- brings out the near colloidal size of the particles as well 
couple well 86 and thermocouple elements 87 are placed, as their tendency toward a hexagonal shape. 
also, in the tube section 54 and a pressure recorder con- The purity of the solid particles ranged as high as 
nection 85 made to the tube section 55, between the con- 98.9 percent by weight of free magnesium. 
denser and first collecting tank. 40 The various method steps and apparatus units as above 
In operating the apparatus, the furnace chamber is described typify successful procedures used in obtaining 
first partly filled with magnesium metal. The system is the product. In lieu of these steps and units, other equiv- 
then evacuated and purged with helium gas to remove alent means may of course be made. For example, a hy- 
all oxygen, and is then pressurized to about 3.5 pounds drocarbon is specified as the condensing medium since 
per square inch with this inert gas. With no flow of ma- 43 the process is described for slurry fuel production. For 
terials through the system, power is applied to heat the other uses, other media are available, the main require- 
furnace, the helium and the nozzle 51. Sufficient heating ment being a boiling point sllfficiently low to permit op- 
of these three items is required to bring the temperature eration at  the afterspray pressures in the system. A 
thereof above the condensation point of the furnace metal usable modification of the condenser, also, is illustrated 
vapors SO as to reduce the likelihood of condensaiion of 50 in Fig. 2. In this arrangement the condenser takes the 
these vapors between the furnace and shock-cooling con- form of a straight tubular chamber 99, attached adjacent 
denser. one end to the outlet tube 91 of furnace 92 and at the 
When the temperature of the liquid-magnesium in the other end connected to the collecting system through tube 
furnace 10 reaches about 1400" F., flow sf niagnesiunl va- section 54, as in the arrangement of Fig. 1. There are 
por is initiated in the flow circuit by reducing the pressure g j  two spray nozzles in this chamber for coolant, one, 93, 
downstream of the furnace nozzle with the vacuum pump at the furnace end of the &amber 98 and directed axially 
and starting the flow of helium gas through the gas heater therethrough, and the other, 94, supported vertically in an 
30 and through the furnace. At the same time the hy- offset shell 95 above an opening in the chamber wall, 
drocarbon is sprayed through nozzles 47, 48 and 49 into so that metal-laden vapor is sprayed successively by 
the condenser chamber. The pressure in the furnace, 60 directed coolant, arrangement, a 
which tends to increase with temperature, is kept con- short sharp-edged orifice 96 is used which has the smallest 
stant by of adjustment of the area at the furnace edge and sides expanding outwardly. flow; also, the pressure downstrea~il of the nozzle is kept In both condenser arrangements, the nozzle at the furnace 
constant by manipulation of the bleeder vslvc 78. 
% shut down the equipment the power to the indue- 65 outlet opens into enlarged condenser spaces so as to in- 
tion heater of the furnace is cue off and the power to tile sure adequate and gas flow with intimate mixing 
helium heater is reduued. When the nlagnesiurn tern- 'Ontact with the condensing mediums. 
perature decreases below 1200" F., the heliam heater is It  is pointed out that using a high mass flow of heated 
turned off, the flow of helium red~ced,  and tile vacuum helium gas through the outlet nozzle prevents the hy- 
pump and condensing liquid spray stopped, the mag- 70 drocarbon from backing into the vaporizer and cracking; 
nesium cooling down to about 200" F. A slight positive also, the hot helium, in conjunction with the heated outlet 
pressure of helium is maintained throughout the cooling nozzle, tends to prevent the metal vapors from condens- 
period. ing and solidifying in the orifice. In order to diminate 
The slurry recovered from the two collectors 53 and alternating current disturbances from the induction coil 
64, the hydrocarbon bath tank 68 and the condensate r g  18 on the thermocouples, each thermocouple is grouodgd 
9,984,881 
5 6 
through a capacitor 98, as shown, for example, applied temperature of the vaporized metal has reached a certain 
to thermocouple 87 of Fig. 1. level, a shock-cooling condenser coupled to said furnace 
Obviously many modifications and variations of the for providing a liquid hydrocarbon coolant in the path of 
present invention are possible in the light of the above travel of said vaporized metal flowing thereto from said 
teachings. It is therefore to be understood that within 5 furnace thereby to rapidly condense said vaporized metal 
the scope of the appended claims the invention may be into minute solid particles suspended in said coolant, a 
practiced otherwise than as specifically described. first enclosed receptacle positioned below said condenser 
What is claimed is: and coupled thereto for collecting the unvaporized hydro- 
1. Apparatus for preparing a slurry having minute carbon coolant and the metallic particles suspended there- 
metallic particles suspended therein comprising a furnace 10 in, means coupled to said condenser and to said first re- 
wherein the metallic material is vaporized, means coupled ceptacle for condensing the vaporized hydrocarbon cool- 
to said furnace for introducing an inert gas therein, a ant, a second enclosed receptacle positioned below said 
condenser coupled to said furnace for providing a liquid last recited means for collecting the condensed hydro- 
coolant spray in the path of travel of the vaporized metal carbon coolant and the metallic particles suspended there- 
flowing thereto from said furnace thereby to rapidly con- 15 in, means including a hydrocarbon bath coupled to said 
dense said vaporized metal into minute solid metallic par- second receptacle for effecting separation of the metallic 
ticles suspended in said coolant, a first receptacle posi- particles from the inert gas, a heat exchanger coupled 
tioned below said condenser and coupled thereto for col- to said last recited means for condensing hydrocarbon 
lecting the unvaporized coolant and the metallic particles vapors flowing therethrough, and means including a vacu- 
suspended therein, means coupled to said condenser and 20 um pump upstream of said heat exchanger for selectively 
to said first receptacle for condensing the coolant vapor, controlling the flow through the apparatus. 
a second receptacle positioned below said last recited 3. Apparatus according to claim 2, and including 
means for collecting the condensed coolant and the metal- means for pre-heating said inert gas. 
lic particles suspended therein, means including a coolant 
bath and a felt filter coupled to said second receptacle for 25 References Cited in the file of this patent 
effecting separation of the metallic particles from the UNITED STATES PATENTS 
inert gas, and means including a vacuum pump upstream 
of said coolant bath for selectively controlling the flow 706,475 Pohl ------------------- Aug. 5, 1902 
through the apparatus. 1,918,283 Miller ----------------- July 18, 1933 
2, Apparatus for preparing a hydrocarbon-slurry hav- 30 1~972~447 Jenkills ----------------- S e ~ t .  4, 1934 
ins minute metallic particles suspended therein compris- 21159,433 Ervin ----------------- May 2 3 ~  1939 
ing a furnace wherein the metallic material is heated and 2~431~554 Hansley et al. ---------- 2 5 ~  1947 
vaporized, means coupled to said furnace for introducing 2~513133~ Loevenstein ------------- July 4, 1950 
an inert gas therein at a rate necessary to maintain the 2,712,497 Fox et al. --------------- July 5, 1955 
pressure within said furnace at  a desired level when the 35 2,712,989 Maisner --------------- July 12, 1955 


Apparatus for making a metal slurry product Patent

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