US 2798364 A
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y 1957 w. MORRISON 2,798,364
MEANS FOR STORING AND TRANSPORTING COLD LIQUID HYDROCARBONS Filed July 8, 1953 2 Sheets-Sheet l 4 l a l I 71 U6 for Wei/"0rd .Z. flfor'rz's'on July 9, 1957 w. MORRISON 2,793,364
I MEANS FOR STORING AND TRANSPORTING COLD LIQUID HYDROCARBONS Filed July 8, 1953 2 Sheets-Sheet 2 QHYCI I I I I I E 2. v M
United States Patent MEANS FOR STORING AND TRANSPORTING COLD LIQUID HYDROCARBONS Willard L. Morrison, Lake Forest, 11]., assignor, by direct and me'sne assignments, to Constock Liquid Methane Corporation, a corporation of Delaware Application July 8, 1953, Serial No. 366,854
7 Claims. (Cl. 62-1) My invention relates to improvements in means for storing and means for transporting cold liquid hydrocarbons at atmospheric pressure and at temperatures in the order of 258 F.
One object of my invention is to provide a tank in which such exceedingly cold liquids may be stored or may be transported without danger that the excessively low temperature will have any deleterious effect on the steel wall of the tank.
I have illustrated this invention in connection with water borne transportation though the invention might be applied to land borne transportation and also to stationary storage.
The ambient air temperature may well vary as much as one hundred or more degrees Fahrenheit. For example, dealing with a barge that travels between Texas gulf ports and Chicago, there will be times when the air temperature to which the barge is exposed might be 115 or more degrees F. and there will be times when the air temperature, when the barge reaches its destination, may be below F. This results in a wide variation in the rate of evaporation and puts a serious burden on the control means.
The water temperature on the other hand in which the barge floats will vary through a much narrower range. It will never be as low as 32 F. and seldom if ever be much above 70 or 80 F.
If variation in the temperature of the steel wall of tank or vessel containing the gas can be held within the range of water temperature variation rather than within the range of air temperature variation, the problem of controlling evaporation will be substantially simplified.
The hydrocarbon with which my apparatus is to be used is highly combustible. It may even be toxic and so it is of the utmost importance that the tank containing it, even though at atmospheric pressure, remain tight and be as little as possible subjected to stresses and strains and distortions resulting from transportation.-
I propose, therefore, that each tank containing this cold liquid will be floated in a water containing well, thus the tank has a water jacket maintaining its temperature relatively constant and the water jacket also serves as a cushion so that shocks and stresses applied to the well will not reach the tank containing the gas.
I propose to provide a steel walled tank preferably cylindrical having its diameter in the horizontal plane much greater than its height. I propose to float this tank in a water bath and to interpose between the shell or wall of the tank and the cold liquid therein, a mass of insulation preferably, though not necessarily, balsa wood which will keep the tank wall from coming into contact with the cold liquid. The insulation may be impregnated with cold gas vaporized from the liquid but the temperature of the gas will be higher than that of the liquid and the cooling effect of the cold gas contacting the steel shell will be much less than would be the cooling effect of the liquid were it allowed to contact the shell.
As a result, the water jacket would only have to supply a relatively small amount of heat to maintain the tank shell at a temperature such that no deleterious elfect results from the presence of the exceedingly cold liquid gas.
Suitable guide means must be provided to center the gas tank in the well while leaving it free to have, within predetermined limits, angular, horizontal and vertical movement. The level of the water in the well must be so controlled that the gas tank will always float, never resting on the floor of the well and never engaging the cover of the well. As the amount of liquid gas in the tank increases as the tank is filled and decreases as the tank is emptied, the displacement of the tank will be in a constant state of flux requiring constant adjustment of the water level so that the tank will float freely at all times. It is important that the water in the well be in a constant state of circulation into the well, about the tank and out of the well as is necessary if the water in the well is to act effectively as a water jacket.
Other objects will appear from time to time throughout the specification and claims.
My invention is illustrated more or less diagrammatically in the accompanying drawings wherein-- Figure l is a plan view in part section of a barge illustrating my invention;
Figure 2 is a section on a larger scale along the line 2-2 of Figure 1.
Like parts are indicated by like characters throughout the specification and drawings.
1 is a hull of a barge or ship or vessel. 2 is a water well built therein as part of the vessel structure. 3 are structural members between the Well 2 and the hull. The Well is preferably cylindrical, preferably extends across a good part of the hull of the vessel and its height is less than its diameter. 4 is the deck of the vessel extending across the top of the well 2. 5 is a cylindrical gas tank adapted to float in the well 2. The tank is of metal, and is smaller in diameter and height than the well. It is lined on top, bottom and sides by insulation 6, preferably balsa wood. Tank 5 is adapted to contain liquefied hydrocarbon such as methane and the like at substantially atmospheric pressure and at temperatures in the order of 25 8 F. The bulsa wood lining 6 keeps the liquefied gas out of contact with the steel wall of the tank 5 so the temperature of the steel wall is much higher than the temperature of the liquefied gas. The tank 5 floats in the well 2 and is maintained in general concentricity with the well, by loosely interlocking guide means 7, which permit radial, angular and axial relative displacement of the gas tank and the water well.
8 is a supply pump driven by a motor 9. It may draw water from the outside of the barge through the conduit 10 for discharge through the conduit 11 to the well 2. Each well includes an annular duct 12 fed from the conduit 11. Valves 13 control the flow from conduit 11 to each separate duct 12. Each duct 12 has a plurality of spray apertures or nozzles 14 which direct the flow of water against the tank wall so that the water may flow downwardly along the wall toward the bottom of the well. Thus even that part of the tank wall not immersed in the bath of water in the well is water heated. 15 is a discharge port at the bottom of the well. It communicates with a discharge passage 16 which discharges topump 16a which discharges through the wall of the vessel to the outside. Ports 17 and 18 controlled by valves 19 and 20 make it possible, if desired, to circulate water from inside the hull. This may be especially desirable in the event that the barge is traveling in heavily silt-laden water.
21 is a finger or needle valve extending downwardly from the bottom of the tank, penetrating the discharge port 15. This finger is tapered so that if the tank tends 3 to sink too far as a result of too rapid discharge of Water, the needle valve will decrease the flow, acting as a safety control, additional to the control which will be subsequently described.
22 is a control valve in the discharge passage 16, adapted to be manipulated to control the rate of dis-v charge of water from each well just as the valves 13 control the rate of supply of water from the pump to each well. The motors driving the supply and discharge pumps will be provided with controls, the details of which form no part of the present invention and are not further illustrated.
23 is a control member interposed between the tank and the well. The details of this member form no part of the present invention. Suflice it to say that this control member preferably electrically controls the valves 13 and 22 and the pumpsand as the displacement of the gas tank increases and a greater depth of water is needed to float the tank, this will be supplied. On the other hand, if the displacement decreases and less depth of water is needed to float the tank and the control will provide it. The essential point being that the amount of Water in the well must at all times be such that the gas tank floats Without contact with the floor or the cover of the well. 24 is a. port in the cover of the tank. 25 is a port in the deck 4 or cover of the well, these ports being in register and joined by an accordion bellows 26. 27 is a housing covering the two aligned ports and the bellows and is adapted to contain any suitable tank loading and unloading mechanism. Details of this mechanism form no part of the present invention and are not here illustrated.
Free flotation of the gas tank is exceedingly important because the tank which holds the gas must be protected from any sudden change in stress and strain resulting from the navigation conditions through which the barge or vessel is exposed.
.The arrangement I propose, therefore, with the freely floating gas tank in a Water well provides for free support of the gas tank and insulation of the tank from any shock or strain applied to or felt through the structure of the vessel and at the same time continued circulation of the flotation water insures a substantially constant temperature of the steel sheel of the gas tank.
The insulation on the interior of the gas tank will in the absence of serious disaster prevent contact of liquid cold gas with the steel tank shell. The gas vaporized therefrom being at rapidly rising temperature as it migrates outwardly may contact the steel shell and it is to insure that the shell will not be cooled thereby below the danger point that water is circulated about the steel shell of the gas tank. If there should be, though it is highly improbable, a leak of gas through the tank wall, such concentration of the gas Will cool the water immediately surrounding the leak so as to freeze it and form an ice plug to limit, if not entirely prevent escape of the gas. The circulation of the water would prevent excessive ice formation and any gas escaping would be kept within the tank 2 and can be discharged through any suitable means adjacent the housing 27.
The water circulation as shown can impinge on the roof of the gas tank and flow thereotf and down along the walls of the tank into the flotation water below. Dealing with the very low temperatures involved, experience teaches that the temperature above the level of the liquid hydrocarbon very rapidly rises above the normal temperature of the liquefied hydrocarbon at atmospheric pressures so under some circumstances it is sulficient to have only the lower portion of the gas tank subjected to the effect of the water warming but no harm is done if the entire surface of the tank is water warmed. As a general proposition a tank on its way to point of use will be very nearly full and it is desirable to have a very etfective water cooling. However, as the tank unloads, the amount of cool hydrocarbon available against which the steel tank must be protected decreases and so since the wei ht of the floating tank decreases at the same time, a decrease in, the amount of water supporting the tank can do no harm.
, tank adapted to contai-na liquid, an inner tank spaced from said outer tank and adapted to contain the liquefied hydrocarbon, mean 'for restraining relative lateral movement between said tanks while permitting limited substantially unopposed relative vertical movement therebetween, an extensible conduit connected with the space within said inner tank and extending out of said outer tank, and means for maintaining in the space between said tanks, a constantly replenished quantity of a liquid, whose freezing' point is above the temperature of the liquefied hydrocarbon, in such amount as to just buoyantly support said inner tank.
2. A structure as defined in claim 1 characterized further in that said inner tank is provided with thermal insulation on all of its faces.
3. A structure as defined in claim 1 characterized further in that said inner tank is prismatic and provided with thermal insulation on all of its faces.
4. A structure as defined in claim 1 characterized further in that said inner tank is prismatic and provided with thermal insulation on all of its faces on its inner periphery.
-5. A structure as defined in claim 1, characterized further in that said liquid between the outer and inner tanks is replenished by sprays impinging'from the inner surface of the outer tank upon the outer surface of the inner tank.
6. A structure as defined in claim 1 characterized further in that said quantity of liquid is circulated to maintain the temperature of the tank walls at about the temperature of the liquid.
7. Means for storing, at about atmospheric pressure, a liquified hydrocarbon gas having a low boiling point at atmospheric pressure, comprising in combination (a) an outer tank adapted to contain water, (b) an inner tank spaced from the outer tank and adapted to contain the liquefied hydrocarbon, (0) means for restraining relative lateral movement between said tanks while permitting limited substantially unopposed relative vertical movement therebetween, (d) an extensible conduit connected with the space Within said inner tank and extending out of said outer tank, (e) means for maintaining in the space between said tanks, a constantly replenished quantity of water whose freezing point is above the temperature of the liquefied hydrocarbon, and (f) spray means mounted to direct a water spray onto the outer surface of the inner tank to stabilize the temperature of the tank wall and to replenish the water between the inner and outer tanks.
References Cited in the file of this patent UNITED STATES PATENTS