MOLTEN MATERIAL FLOW CONTROL

Abstract

A method and system is presented for controlling high-temperature molten material flow. A displacer in the system is a mass of material that can variably displace molten material, thereby increasing the height of the top surface of the molten material in a vessel. The displacer may be positioned above or partially immersed in the molten material. The vessel includes an output port at a height that may be at, above, or below the top surface of the molten material, depending on the amount of immersion of the displacer. The method of controlling the flow of the molten material may further include selecting a flow rate for the molten material to flow out of the vessel through the output port and immersing the displacer in the molten material by an amount that is based, at least in part, on the selected flow rate.

Claims

1. A method of controlling flow of a high-temperature molten material, the method comprising: positioning a displacer above or partially immersed in the high-temperature molten material that is contained in a vessel with an output port above the high-temperature molten material; selecting a flow rate for the high-temperature molten material to flow out of the vessel through the output port; and immersing or further immersing the displacer in the high-temperature molten material by an amount that is based, at least in part, on the selected flow rate.

2. The method of claim 1, wherein the high-temperature molten material is molten lunar regolith.

3. The method of claim 1, further comprising increasing a depth of immersion of the displacer to increase the flow rate of the high-temperature molten material through the output port.

4. The method of claim 1, further comprising continuously increasing a depth of immersion of the displacer to maintain a constant flow rate of the high-temperature molten material through the output port.

5. The method of claim 1, further comprising, while the displacer is positioned above the high-temperature molten material, preheating the displacer to a temperature that is substantially the same as or above the temperature of the high-temperature molten material.

6. The method of claim 1, further comprising, while the displacer is partially immersed in the high-temperature molten material, applying an electric potential on the displacer to perform electrolysis on the high-temperature molten material.

7. The method of claim 6, wherein the electric potential is a positive potential and the displacer is an anode of the electrolysis.

8. The method of claim 1, further comprising performing molten oxide electrolysis (MOE) on the high-temperature molten material, wherein a molten iron cathode is at a bottom portion of the vessel.

9. The method of claim 8, further comprising: measuring conductivity of the high-temperature molten material flowing out of the vessel through the output port; and to avoid removing a substantial portion of the molten iron cathode, decreasing the amount of immersion of the displacer if the conductivity reaches a predetermined threshold.

10. The method of claim 8, further comprising collecting, above the displacer, oxygen produced by the MOE.

11. The method of claim 8, further comprising collecting, via the output port, oxygen produced by the MOE.

12. A high-temperature molten material flow system comprising: a vessel configured to contain a high-temperature molten material; an output port at a particular height in a side of the vessel and configured to convey a portion of the high-temperature molten material that is at or above the particular height of the output port; a displacer inside the vessel and configured to be immersed at variable depths in the high-temperature molten material; an actuator to immerse the displacer at the variable depths in the high-temperature molten material; and an electronic controller to i) receive a signal representative of a selected flow rate for the high-temperature molten material to flow out of the vessel through the output port and ii) operate the actuator to immerse the displacer in the high-temperature molten material by an amount that is based, at least in part, on the selected flow rate.

13. The flow system of claim 12, wherein the displacer is an anode configured to be held at a positive electrical potential and the high-temperature molten material is an electrolyte.

14. The flow system of claim 13, further comprising a molten iron cathode at a bottom portion of the vessel.

15. The flow system of claim 12, wherein the electronic controller is configured to increase a depth of immersion of the displacer to increase the flow rate of the high-temperature molten material through the output port.

16. The flow system of claim 12, wherein the electronic controller is configured to continuously increase a depth of immersion of the displacer to maintain a constant flow rate of the high-temperature molten material through the output port.

17. The flow system of claim 12, further comprising a height sensor to measure the height of the high-temperature molten material in the vessel.

18. The flow system of claim 12, wherein the displacer is made of one or more refractory materials.

19. The flow system of claim 12, wherein a top surface of the displacer is sloped to allow the high-temperature molten material to flow off of the top surface.

20. The flow system of claim 12, wherein the high-temperature molten material is molten lunar regolith.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The disclosure will be understood more fully from the detailed description given below and from the accompanying figures of embodiments of the disclosure. The figures are used to provide knowledge and understanding of embodiments of the disclosure and do not limit the scope of the disclosure to these specific embodiments. Furthermore, the figures are not necessarily drawn to scale.

[0004] FIG. 1 is a schematic cross-section side view of a high-temperature molten material flow system, according to some embodiments.

[0005] FIG. 2 is a schematic cross-section side view of the high-temperature molten material flow system with a displacer in an immersed position, according to some embodiments.

[0006] FIG. 3 is a schematic cross-section side view of the high-temperature molten material flow system with the position of the displacer leading to a low pressure fluid flow through an output port, according to some embodiments.

[0007] FIG. 4 is a schematic cross-section side view of the high-temperature molten material flow system with the position of the displacer leading to a relatively high pressure fluid flow through the output port, according to some embodiments.

[0008] FIG. 5 is a schematic cross-section side view of a high-temperature molten material flow system that incorporates a molten oxide electrolysis process, according to some embodiments.

[0009] FIG. 6 is a flow diagram of a process for controlling high-temperature molten material flow, according to some embodiments.

DETAILED DESCRIPTION

[0010] This disclosure describes, among other things, a method and system for controlling high-temperature molten material flow. Generally, a liquid flow may be controlled by valves or gates, but a high-temperature molten material may present a number of difficulties for the use of valves or gates. A high-temperature molten material, as applied to methods or systems described herein, is considered to have a temperature greater than about 1000 degrees centigrade. For example, molten lunar regolith may be at a temperature of about 1900 degrees C. At such high temperatures, valves or gates must be made of high temperature tolerant refractory materials or refractory metals and must be able to control the flow of liquid having a relatively high viscosity. Even properly designed valves or gates may face difficulties such as jamming, sticking, or decomposition due to, among other things, inconsistencies in the high-temperature molten material.

[0011] Though examples herein may be directed to high-temperature molten material that is molten lunar regolith and electrolyte formed therefrom, claimed subject matter is not limited in this respect. For example, benefits may be realized by using herein-described methods or systems for controlling flows of liquids other than molten lunar regolith or high-temperature molten material.

[0012] In some embodiments, a method of controlling the flow of a high-temperature molten material, hereinafter called molten material, may include positioning a displacer above or partially immersed in the molten material that is contained in a vessel. As described in detail below, the displacer may be a mass of material that can variably displace the molten material, thereby increasing the height of the top surface of the molten material, when the displacer is immersed in the molten material. The vessel may include an output port at a height that may be at, above, or below the top surface of the molten material, depending on the amount of immersion of the displacer. The method of controlling the flow of the molten material may further include selecting a flow rate for the molten material to flow out of the vessel through the output port and immersing the displacer in the molten material by an amount that is based, at least in part, on the selected flow rate. In some implementations, increasing a depth of immersion of the displacer may increase the flow rate of the molten material through the output port. In some implementations, continuously increasing a depth of immersion of the displacer may maintain a constant flow rate of the molten material through the output port.

[0013] In some embodiments, to avoid condensation of molten material on the displacer surface, the displacer may be preheated while it is positioned above the molten material. For example, condensation or buildup of material on the displacer may be substantially avoided by preheating the displacer to a temperature that is about the same as or above the temperature of the molten material.

[0014] In some embodiments, the displacer may have a dual function of variable liquid displacement and being an anode for electrolysis of the molten material. For example, a positive electric potential may be applied to the displacer. The electrolysis may be molten oxide electrolysis (MOE) performed on molten lunar regolith as the molten material. As explained below, the MOE process may involve a molten iron cathode at a bottom portion of the vessel.

[0015] In some embodiments, a flow system that may be used to perform the method described above may include a vessel configured to contain a molten material, an output port at a particular height in a side of the vessel and configured to convey a portion of the molten material that is at or above the particular height of the output port, a displacer inside the vessel and configured to be immersed at variable depths in the molten material, an actuator to immerse the displacer at the variable depths in the molten material, and an electronic controller to i) receive a signal representative of a selected flow rate for the molten material to flow out of the vessel through the output port and ii) operate the actuator to immerse the displacer in the molten material by an amount that is based, at least in part, on the selected flow rate. The flow system is described in detail below.

[0016] FIGS. 1 and 2 are schematic cross-section side views of a high-temperature molten material flow system 100, according to various embodiments. Both figures illustrate the same system. For illustrative clarity, some features and components of flow system 100 are illustrated only in FIG. 1.

[0017] Flow system 100 may include a vessel 102 configured to contain a molten material 104 and having an output port 106 at a particular height in a side of the vessel. Output port 106 may be configured to convey a portion of the molten material that is at or above the particular height of the output port, as explained below. A displacer 108 may be inside the vessel and configured to be immersed at variable depths in molten material 104. An actuator 110 may be used to immerse displacer 108 at the variable depths in the molten material. In some implementations, vessel 102 and displacer 108 may be made of one or more refractory materials that can withstand refractory temperatures.

[0018] An electronic controller 112 may perform various functions or operations for flow system 100. The electronic controller may be a computer processor, as described below, for example. Electronic controller 112 may receive, possibly via a user interface, a signal representative of a selected flow rate for molten material 104 to flow out of vessel 102 through output port 106. Accordingly, the electronic controller may operate actuator 110 to immerse displacer 108 in the molten material by an amount that is based, at least in part, on the selected flow rate. For example, FIG. 1 illustrates displacer 108 above and separate from molten material 104 so that no displacement of the molten material occurs and the top level of the molten material is below a bottom of output port 106 by a distance 114. In some situations, even if displacer 108 is partially immersed in molten material 104, a resulting displacement may still be insufficient to raise the top level of the molten material to the height of output port 106. In any case, these situations and others that result in the top level of the molten material being below the height of output port 106 have the outcome of zero flow out of vessel 102. In contrast, as illustrated in FIG. 2, displacer 108 may be immersed into molten material 104 by an amount that results in the top level of the molten material being above the bottom of output port 106 such as by a distance 116. This situation leads to flow of the molten material out of vessel 102 through output port 106, as indicated by arrow 118. As explained below, increasing the amount of displaced molten material may result in an increase in flow rate of the molten material through the output port.

[0019] As just described above, there may be some situations where the top level of the molten material is below the height of output port 106, having the outcome of zero molten material flow out of vessel 102. In some implementations, however, such situations may be utilized to collect oxygen through output port 106. For example, if flow system 100 involves an MOE process, oxygen may be produced and accumulate above the top surface of molten material 104 (e.g., electrolyte). With the top level of the molten material being below the height of output port 106, oxygen may flow out of vessel 102 via the output port. This is described below.

[0020] Flow system 100 may include a height sensor 120 to measure the height of high-temperature molten material 104 in vessel 102. For example height sensor 120 may include an ultrasonic transmitter or laser rangefinder and measure a time-of-flight of an emitted signal 122 that reflects from the top level of molten material 104. Electronic controller 112 may receive height measurements from height sensor 120 periodically, continuously, or from time to time.

[0021] In some embodiments, flow system 100 may include a lid 124 that covers the contents of vessel 102. The lid may be sealed at the interface with the top of vessel 102 so gases, such as oxygen, may be contained in the vessel above molten material 104. Lid 124 may include a pass-through 126 (e.g., a vacuum flange) that allows a shaft 128 to move vertically up and down by actuator 110, as indicated by arrow 130, Shaft 128, being connected to displacer 108, may impart its vertical motion to varying the amount of immersion of the displacer in molten material 104.

[0022] In some embodiments, to avoid condensation of molten material 104 on the displacer surface, displacer 108 may be preheated while it is positioned above the molten material. For example, as mentioned above, condensation or buildup of material on the displacer may be substantially avoided by preheating the displacer to a temperature that is about the same as or above the temperature of the molten material. This may be accomplished, for example, by exposing displacer 108 to ambient temperatures that are present above molten material 104. In some implementations, a top surface 132 of displacer 108 may be sloped to allow molten material 104 to gravity-flow off of the top surface.

[0023] FIG. 3 is a schematic cross-section side view of high-temperature molten material flow system 100 with the position of displacer 108 leading to a relatively low pressure fluid flow through output port 106, according to some embodiments. In contrast to the situation depicted in FIG. 1, wherein the top level of molten material 104 is below the height of output port 106 so that there is zero flow into output port 106, displacer 108 may be immersed into molten material 104 by an amount that results in the top level of the molten material being above output port 106 by a distance 302. This situation leads to flow of the molten material out of vessel 102 through output port 106, as indicated by arrow 304. This is in further contrast to the situation depicted in FIG. 2 wherein the top level of the molten material is just above the bottom of output port 106. The flow in FIG. 3 may be substantially greater than the flow in FIG. 2 because increasing the amount of displaced molten material may result in an increase in flow rate of the molten material through the output port. An increased flow rate into output port 106 generally corresponds to an increase in pressure at the output port. Thus, changing the depth of displacer (e.g., the amount of immersion) may result in changing the pressure at the output port by increasing the height of the top of molten material 104 above output port 106.

[0024] FIG. 4 is a schematic cross-section side view of high-temperature molten material flow system 100 with the position of displacer 108 leading to a relatively high pressure fluid flow through output port 106, according to some embodiments. As explained above, increasing the amount of displaced molten material may result in an increase in flow rate of the molten material through output port 106. Comparing with the situation depicted in FIG. 3, displacer 108 in FIG. 4 is further immersed in molten material 104 and the molten material is thus further displaced so as to have its top surface higher above output port 106, by a distance 402, resulting in an increased flow rate indicated by arrow 404 (again, in comparison to the situation of FIG. 3).

[0025] In some implementations, electronic controller 112 of flow system 100 may increase a depth of immersion of displacer 108 to increase the flow rate of molten material 104 through output port 106 or, on the other hand, decrease a depth of immersion of the displacer to decrease the flow rate of the molten material through the output port. In some implementations, as molten material 104 is depleted by the gradual outflow of the molten material through the output port, the electronic controller may maintain a constant flow rate (e.g., a constant pressure) by gradually increasing a depth of immersion of displacer 108 so that distance 402 (or 302) is held constant. Height sensor 120 may provide the height information of molten material 104 to electronic controller 112 to allow the electronic controller to operate actuator 110 for controlling the depth of immersion of displacer 108, for example.

[0026] FIG. 5 is a schematic cross-section side view of a high-temperature molten material flow system 500 that may incorporate an MOE process, according to some embodiments. Flow system 500 may be the same as or similar to flow system 100, in some examples, with added features of MOE.

[0027] Flow system 500 may include a vessel 502 configured to contain a molten material 504 and having an output port 506 at a particular height in a side of the vessel. Output port 506 may be configured to convey a portion of the molten material that is at or above the particular height of the output port, as explained above for flow system 100. A displacer 508 may be inside the vessel and configured to be immersed at variable depths in molten material 504. An actuator 510 may be used to immerse displacer 508 at the variable depths in the molten material. In some implementations, vessel 502 and displacer 508 may be made of one or more refractory materials that can withstand refractory temperatures.

[0028] Flow system 500 may include a height sensor 512 to measure the height of high-temperature molten material 504 in vessel 502. An electronic controller 514, similar to or the same as electronic controller 112, may receive height measurements from height sensor 512 periodically, continuously, or from time to time. Flow system 500 may include a lid 516 that covers the contents of vessel 502. The lid may be sealed at the interface with the top of vessel 502 so gases, such as oxygen, may be contained in the vessel above molten material 504. Lid 516 may include a pass-through (e.g., 126) that allows a shaft 518 connected to displacer 508 to move vertically up and down by actuator 510. Similar to shaft 128 of flow system 100, shaft 518 may impart its vertical motion to varying the amount of immersion of displacer 508 in molten material 504.

[0029] During a process of MOE, the amount of immersion of displacer 508 may be such that the top level of molten material 504 is below a bottom of output port 506, such as by a distance 520, for example. Electronic controller 514 may perform various functions or operations for flow system 500 including controlling the MOE process, which may involve applying an electric potential 522 to displacer 508 so that the displacer acts as an anode of the MOE process. In this case, the electric potential may be positive (e.g., a positive voltage) and applied via an electrode 524. Counter to this, a negative potential may be applied to an electrode 526 at or near the bottom of vessel 502. Electrode 526 may in turn energize a molten iron cathode 528 at the bottom of vessel 502 during the MOE process.

[0030] In some implementations, the top level of molten material 504 may be below the bottom of output port 506, as illustrated. In other implementations, however, the top level of the molten material may be above the bottom of the output port. As a result of the MOE process, molten material 504 may be electrolyte, which may be iron-depleted and oxygen depleted molten regolith, for example. The MOE process generally pulls iron out of the molten material and accumulates the iron onto molten iron cathode 528. Also, the MOE process pulls oxygen out of the molten material to the anode (e.g., displacer 508) and into the space 530 above the top level of molten material 504 and below lid 516. Thus, a collection of oxygen gas 532 accumulates in space 530, from where it may be harvested for use in some example implementations.

[0031] In situations where the top level of the molten material is below the height of output port 506, molten material may not flow out of vessel 102 but oxygen gas 532 may do so. For example, output port 506 may lead to an oxygen-collecting port 534 and a separate molten material-collecting port 536. When the top level of the molten material is above the top of output port 506, oxygen gas 532 may not flow out of vessel 102 via output port 506 (though in some implementations there may be another output path for collecting oxygen 532 from vessel 502) while molten material does so, blocking the oxygen gas from exiting.

[0032] During a process of collecting or harvesting molten material 504, which may be an electrolyte, electronic controller 514 may, in a continuing fashion, lower displacer 508 so that the top level of the molten material remains above the bottom of output port 506 and flow therethrough is maintained at a constant flow rate. This process may continue until the molten material is depleted, at which point displacer 508 may begin to be partially immersed in molten iron cathode 528. When this occurs, molten material 504 flowing into output port 506 may become iron-rich. This situation may be undesirable for at least two reasons. First, a goal of collecting or harvesting molten material 504 may be to acquire iron-depleted electrolyte. Second, it may be undesirable to deplete the mass of molten iron cathode 528. To avoid iron-rich molten material from exiting vessel 502 via output port 506, flow system 500 may include a conductivity sensor 538 in output port 506 to measure conductivity or resistivity of molten material 504 flowing out of vessel 502 through the output port. Electronic controller 514 may receive measurements from the conductivity sensor and control the amount of immersion of displacer 508 based on the measured conductivity of the molten material flow. For example, the conductivity of the molten material flow may depend, at least in part, on a concentration of iron therein. Thus, an increase in conductivity may indicate that the molten material flow into output port 506 is beginning to include some of molten iron cathode 528. In some implementations, if the conductivity reaches a predetermined threshold, the electronic controller may decrease the amount of immersion of displacer 508 to stop the flow into output port 506.

[0033] FIG. 6 is a flow diagram of a process 600 for controlling high-temperature molten material flow, according to some embodiments. The process may be performed by an operator, which may be a person or persons, a computer processor executing computer-readable code, or a combination thereof. For example, the process may be performed by electronic controller 112 or 514, at least in part, using flow systems 100 or 500. In some implementations, either of these electronic controllers may be a computer processor that includes any type of computing device having one or more processing units operably connected to computer-readable media. The computer-readable media may include two types of computer-readable media, namely computer storage media and communication media. Computer storage media may include volatile and non-volatile machine-readable, removable, and non-removable media implemented in any method or technology for storage of information (in compressed or uncompressed form), such as computer (or other electronic device) readable instructions, data structures, program modules, or other data to perform processes or methods described herein. Communication media may embody computer-readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave, or other transmission mechanism.

[0034] In some examples, computer-readable media may store instructions executable by electronic controller 112 or 514. Computer-readable media may also store instructions executable by an external CPU-based processor, executable by a GPU, and/or executable by an accelerator, such as an FPGA-based accelerator, a DSP-based accelerator, or any internal or external accelerator, just to name a few examples. Executable instructions stored on computer-readable media may include, for example, an operating system and other modules, programs, or applications that may be loadable and executable by electronic controller 112 or 514.

[0035] Though process 600 may be performed using other flow systems, for sake of example, process 600 will be described as being performed on flow system 500. At 602, the operator may position displacer 508 above or partially immersed in molten material 504 that is contained in vessel 502 with an output port 506 above the molten material. The molten material may be molten lunar regolith, for example. In some flow systems, the displacer and the vessel may be made of refractory materials at least for the reason that the molten material may be at refractory temperatures.

[0036] At 604, the operator may select a flow rate, or one or more flow rates may already be a priori selected for the molten material to flow out of the vessel through the output port. For example, pre-selected flow rates may be established for specific times during process 600. At 606, the operator may immerse or further immerse the displacer in the molten material by an amount that is based, at least in part, on the selected flow rate(s). The operator may increase a depth of immersion of the displacer to increase the flow rate of the high-temperature molten material through the output port. Also, the operator may continuously increase a depth of immersion of the displacer to maintain a constant flow rate of the molten material through the output port.

[0037] In some implementations, the operator may, while the displacer is positioned above the molten material, preheat the displacer to a temperature that is substantially the same as or above the temperature of the molten material.

[0038] In some implementations, while the displacer is partially immersed in the molten material, the operator may apply an electric potential on the displacer to perform electrolysis on the molten material. The electric potential may be a positive potential so that the displacer acts as an anode of the electrolysis, as described above.

[0039] The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the disclosure. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the systems and methods described herein. The foregoing descriptions of specific embodiments or examples are presented by way of examples for purposes of illustration and description. They are not intended to be exhaustive of or to limit this disclosure to the precise forms described. Many modifications and variations are possible in view of the above teachings. The embodiments or examples are shown and described in order to best explain the principles of this disclosure and practical applications, to thereby enable others skilled in the art to best utilize this disclosure and various embodiments or examples with various modifications as are suited to the particular use contemplated. It is intended that the scope of this disclosure be defined by the following claims and their equivalents.