Apparatus and method for separating liquid oxygen from liquified air

Abstract

An apparatus and method of separation of LOX and other commercially valuable components, such as LAr from liquefied air, which consists primarily of LN2. Strong magnetic field gradient and gravity are used to separate LOX from liquefied air, based upon the different magnetic properties of LOX and LN2. The apparatus and method employ a magnetic field gradient to levitate the LN2 and LAr diamagnetic components of liquid air while accelerating the paramagnetic LOX component toward the bottom to achieve oxygen separation. In other embodiments, a leak valve system can be used.

Claims

1. A method of separating liquid oxygen from liquid air comprising: (a) storing liquid air in a liquid air storage container, wherein the liquid storage container comprises (i) a bottom section that has a portion of the liquid air that is rich in liquid oxygen due to gravity, and (ii) a top portion that has air vapor; (b) flowing liquid air from the bottom section to a separation system, wherein the separation system comprises a magnetic field system and a leak valve system; (c) utilizing the separation system to separate liquid oxygen from the liquid air that is rich in liquid oxygen; and (d) collecting the liquid oxygen in a second storage container.

2. The method of claim 1, wherein the liquid oxygen is collected in the second storage container via gravity.

3. The method of claim 1, wherein the utilizing the separation system comprises utilizing the magnetic field to levitate liquid oxygen from the liquid air based upon the different magnetic properties of liquid oxygen and liquid nitrogen.

4. The method of claim 1, wherein the magnet comprises a gradient coil.

5. The method of claim 4, wherein the gradient coil is wound to achieve a field and gradient that is between about 105% and about 140% of the requirement to levitate liquid oxygen.

6. The method of claim 4, wherein the gradient coil is wound to achieve a field and gradient that is between about 8.5 T.sup.2/m and about 11.5 T.sup.2/m.

7. The method of claim 1, wherein the utilizing the separation system comprises utilizing the leak valve system using one or more adjustable controllers and sensors to separate liquid oxygen from the liquid air.

8. The method of claim 1, wherein the collecting liquid oxygen in the second storage container comprises collecting ultra-pure liquid oxygen in the second container.

9. The method of claim 8, wherein the ultra-pure liquid oxygen is at least about 98% liquid oxygen by weight.

10. The method of claim 8, wherein the ultra-pure liquid oxygen is at least about 99.5% liquid oxygen by weight.

11. The method of claim 8, wherein the ultra-pure liquid oxygen is at least about 98% liquid oxygen by mole.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For better understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings.

(2) FIG. 1A illustrates a system of the present invention that utilizes an accelerator magnet.

(3) FIG. 1B illustrates an alternative system of the present invention that utilizes an accelerator magnet.

(4) FIG. 2 illustrates another system of the present invention that utilizes a leak valve.

(5) FIG. 3 illustrates another system of the present invention that utilizes an accelerator magnet and leak valve.

DETAILED DESCRIPTION

(6) The present disclosure relates generally to devices and methods for separating liquid oxygen and other gas condensates.

(7) System Having a Magnetic Field

(8) Referring to FIG. 1A, FIG. 1A illustrates a system 100 that can be used to separate liquid oxygen from liquid air. Liquid air 103 is stored in liquid air storage container 101. Air vapor 102 is located at the top of container 101. The bottom of container 101 has a liquid that is rich in liquid oxygen (LOX-rich liquid 104) due to gravity. (As shown in downward arrow 105, gravity is directed downward relative to the orientation of system 100). The LOX-rich liquid flows through conduit 106 to a magnetic field system 107, which generates a magnetic field gradient that will create a field and gradient (BVB) that will levitate the LOX.

(9) For instance, magnetic field system 107 can be an accelerator magnet that includes a gradient coil 110, a high field coil 109, and a high-field shim coil 108. The gradient coil 110 can be wound to achieve B∇B that is in the range between around 105% and around 140% (such as around 120%) of the requirement to levitate the LOX. As discussed below, this has been determined to be in the range between around 8.5 and around 11.5 10 T.sup.2/m (such as around 10 T.sup.2/m). The high field coil 109 is wound to produce around 105% to around 140% (such as around 120%) of the maximum field on gradient coil 110. The high-field shim coil is wound to fine tune the gradient field right before the bending to conduit 111 (which is, as shown in FIG. 1A is horizontal). The liquid oxygen is then collected through conduit 111 to LOX storage container 112 (which contains LOX 113).

(10) In alternative embodiments, the accelerator magnet can include only gradient coil 110 with adjustable strength to obviate the need for high field coil 109 and a high-field shim coil 108.

(11) Magnetic Levitation

(12) As noted above, a B∇B that is in the range between around 105% and around 140% (such as around 120%) has been found to be the requirement to levitate the LOX. Calculation of this was shown as follows. The magneto-mechanical force (F.sub.m) is set forth by the equation:
F.sub.m=m∇B=½(χ/μ.sub.0)V∇B.sup.2  (1)
where,

(13) m is the magnetic moment;

(14) χ is the (tensorial) magnetic susceptibility;

(15) μ.sub.0 is the permeability of free space;

(16) V is the volume; and

(17) B is the magnetic flux density.

(18) The gravitation force (F.sub.g) is set forth by the equation:
F.sub.g=ρVg  (2)
where,

(19) ρ is the density;

(20) g is gravity.

(21) A metastable equilibrium, or levitation, can be created for F.sub.m−F.sub.g=0 by proper orientation of the B-vector and proper choice of the magnitude of the gradient ∇B.sup.2. See Hagen, W. R., “Biological Systems In High Magnetic Field,” High Magnetic Field: Science and Technology, Vol. 3, 210 (2006) (“Hagen”).

(22) Setting equations (1) and (2) equal to each other yields:
½(χ/μ.sub.0)V∇B.sup.2=ρVg  (3)

(23) This equation simplifies to:
∇B.sup.2=2ρgμ.sub.0/χ  (4)

(24) Utilizing equation (4), this calculates that for LOX, ∇B.sup.2.sub.LOX is around 8.1 T.sup.2/m. This is a very modest field in comparison with LN2, in which ∇B.sup.2.sub.LN2 is around −2500 T.sup.2/m.

(25) Magnetic Field

(26) For LOX, for levitation, ∇B.sup.2≥8.1 T.sup.2/m. In embodiments of the invention for LOX separation, the field can be set as follows:
B=kμ.sub.0nI  (5)
where

(27) k is the relative permeability;

(28) n is the turns/m; and

(29) I is the current.

(30) Turning to kμ.sub.0:
kμ.sub.0=μ  (6)
μ/μ.sub.0=1+χ  (7)

(31) Since χ for LOX is 3.5×10.sup.−3, the paramagnetic moment of LOX makes only a small correction (<1%) of the field calculations, and this can ignored for levitation purposes. For equation (5) this yields:
B=μ.sub.0nI  (8)
∇B=μ.sub.0∇n  (9)

(32) Using equations (8) and (9), this yields for B∇B:
B∇B=μ.sub.0.sup.2I.sup.2(n∇n)  (10)

(33) Conventionally and often, I is utilized at 10 amps.

(34) μ.sub.0 is 4π×10.sup.−7 T/amp/m and a constant of nature.

(35) Therefore μ.sub.0.sup.2I.sup.2=˜1.58×10.sup.−10 T.sup.2/m.sup.2 for 10 amps. So for 10 amps, to levitate LOX (utilizing equation (10)):
B∇B=8.1 T.sup.2/m=1.58×10.sup.−10 T.sup.2/m.sup.2(n∇n)  (11)

(36) Solving equation (11) for n∇n,
(n∇n)=5.1×10.sup.10(turns).sup.2/m.sup.3  (12)

(37) So with n=10.sup.3 turns/m, equation (12) yields:
∇n=5.1×10.sup.7 turns/m.sup.2=5.1×10.sup.3 turns/cm per cm  (13)

(38) This process of determining ∇n and designing the coils (such as turns per cm) can be used when setting the field in embodiments of the present invention. As noted above, for LOX, the apparatus of the present invention generally utilizes B∇B that in the range between around 105% and around 140% (such as around 120%) of the requirement to levitate the LOX. Note here that I=10 A is an arbitrary example above. This current may be readily increased to higher values, such as 100 A or even 1000 A in order to reduce the size of the required product of n n.

(39) FIG. 1B illustrates an alternative system 114 that can be used to separate liquid oxygen from liquid air. This includes many of the same features as systems 100. In FIG. 1B, conduit 106 flows the LOX-rich fluid to the magnetic system 107 and utilizes the magnetic field system 107 to employ a magnetic field gradient to levitate the LN2 and LAr diamagnetic components of liquid air in conduit 115 (for collection if so desired) while directing the paramagnetic LOX component toward the bottom (in conduit 111) to achieve oxygen separation.

(40) System Having a Leak Valve

(41) An alternative embodiment of the present invention can utilize a leak valve (either adjustable or permanent), as shown in FIG. 2. FIG. 2 illustrates a system 200 that can also be used to separate liquid oxygen from liquid air. As with system 100, liquid air 103 is stored in liquid air storage container 101. Air vapor 102 is located at the top of container 101. The bottom of container 101 has LOX-rich liquid 104. The LOX-rich liquid flows through leak valve system 201, which includes a leak valve 202 that is adjustable by controllers/sensors 203-204. The liquid oxygen is then collected (via gravity) to LOX storage container 112 (which contains LOX 113).

(42) System Having a Magnetic Field and a Leak Valve

(43) A further embodiment of the present invention can utilize both a magnetic field and a leak valve system. FIG. 3 illustrates a system 300 that can also be used to separate liquid oxygen from liquid air that includes a magnetic field system (such as an accelerator magnet that includes a gradient coil 110, a high field coil 109, and a high-field shim coil 108) in combination with a leak valve system (such as leak valve 202 that is adjustable by controllers/sensors 203-204).

(44) The examples provided herein are to more fully illustrate some of the embodiments of the present invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the Applicant to function well in the practice of the invention, and thus can be considered to constitute exemplary modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments that are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention.

(45) While embodiments of the invention have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the invention. The embodiments described and the examples provided herein are exemplary only, and are not intended to be limiting. Many variations and modifications of the invention disclosed herein are possible and are within the scope of the invention. Accordingly, other embodiments are within the scope of the following claims. The scope of protection is not limited by the description set out above.

(46) Concentrations, amounts, and other numerical data may be presented herein in a range format. It is to be understood that such range format is used merely for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a numerical range of approximately 1 to approximately 4.5 should be interpreted to include not only the explicitly recited limits of 1 to approximately 4.5, but also to include individual numerals such as 2, 3, 4, and sub-ranges such as 1 to 3, 2 to 4, etc. The same principle applies to ranges reciting only one numerical value, such as “less than approximately 4.5,” which should be interpreted to include all of the above-recited values and ranges. Further, such an interpretation should apply regardless of the breadth of the range or the characteristic being described.

(47) Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the presently disclosed subject matter belongs. Although any methods, devices, and materials similar or equivalent to those described herein can be used in the practice or testing of the presently disclosed subject matter, representative methods, devices, and materials are now described.

(48) Following long-standing patent law convention, the terms “a” and “an” mean “one or more” when used in this application, including the claims.

(49) Unless otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in this specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the presently disclosed subject matter.

(50) As used herein, the term “about,” when referring to a value or to an amount of mass, weight, time, volume, concentration or percentage is meant to encompass variations of in some embodiments ±20%, in some embodiments ±10%, in some embodiments ±5%, in some embodiments ±1%, in some embodiments ±0.5%, and in some embodiments ±0.1% from the specified amount, as such variations are appropriate to perform the disclosed method.

(51) As used herein, the term “and/or” when used in the context of a listing of entities, refers to the entities being present singly or in combination. Thus, for example, the phrase “A, B, C, and/or D” includes A, B, C, and D individually, but also includes any and all combinations and subcombinations of A, B, C, and D.

RELATED PATENTS AND PUBLICATIONS

(52) The following patents and publications relate to the present invention:

(53) U.S. Pat. No. 4,547,277, entitled “Oxygen separator,” to Lawless, issued Oct. 15, 1985.

(54) U.S. Pat. No. 4,433,989, entitled “Air separation with medium pressure enrichment,” to Erickson, issued Feb. 28, 1984.

(55) China Patent No. 101033909A, filed Apr. 11, 2007.

(56) The disclosures of all patents, patent applications, and publications cited herein are hereby incorporated herein by reference in their entirety, to the extent that they provide exemplary, procedural, or other details supplementary to those set forth herein.