a is one embodiment of a fluid discharge device arrangement useful in accordance with the present invention.
b is another embodiment of a fluid discharge device arrangement useful in accordance with the present invention.
a is a top, cross-sectional view of a portion of
b is a top, cross-sectional view of another portion of
a is a schematic view of one embodiment of methods useful in cooling sidewalls of electrolysis cells in accordance with the present invention.
b is a schematic view of one embodiment of methods useful in cooling sidewalls of electrolysis cells in accordance with the present invention.
Reference will now be made to the accompanying drawings, which at least assist in illustrating various pertinent features of the present invention.
More particularly and with reference to
To facilitate selective control of the ledge 8 profile, it may be desirable to employ a controller to control the discharge of coolant from the nozzle(s) 36. One embodiment of a control arrangement is schematically illustrated in
The nozzle(s) 36 and sensory devices may be disposed within the electrolytic cell 1 at any suitable location(s). In a particular embodiment, the nozzle(s) 36 are partially disposed within the gap 38, as illustrated in
Temperature sensor(s) 64 may be disposed within the electrolytic cell 1. In one embodiment, the temperature sensor(s) 64 may be disposed within the gap 38 for measuring the temperature of the fluids located therein (e.g., air within the gap 38). The controller 60 may receive signals/data from the temperature sensor(s) 64 and, in response, determine the temperature of one or more portions of the sidewall 20. For example, the controller 60 may receive temperature measurements associated with lower, middle and/or upper portions of the sidewall 20. The temperature sensor(s) 64 may be any temperature sensors adapted for use in an electrolytic cell environment, such as a thermocouple.
Heat flux meter(s) 66 may be disposed within the electrolytic cell 1. In one embodiment, the heat flux meter(s) may be interconnected to various portions of the sidewall 20 for measuring the heat flux of such portions of the sidewall 20, The controller 60 may receive signals/data from the heat flux meter(s) 66 and, in response, determine the heat flux of one or more portions of the sidewall 20. For example, the controller 60 may receive heat flux measurements associated with lower, middle, and/or upper portions of the sidewall 20. The heat flux meter(s) 62 may be any heat flux meter(s) adapted for use in an electrolytic cell environment, such as a HT-50 thermal flux sensor available from International Thermal Instrument Company, Del Mar, Calif.
The controller 60 may utilize the information/data from the sensory devices to achieve the desired the cooling rates. In this regard, the controller 60 may be a computerized device (e.g., a general purpose computer) and may utilize one or more of a temperature measurement, flow rate measurement, and/or heat flux measurement to determine an appropriate control response. For example, the controller 60 may determine (e.g., calculate via a digital processor) that the temperature within a portion of the electrolytic cell 1 is relatively high and/or determine that the heat flux associated with a portion of the sidewall 20 is relatively low. In turn, the controller 60 may send an appropriate signal to valve(s) 68 interconnected to the nozzle(s) 36 to increase coolant flow rates to the nozzle(s) 36, thereby increasing the cooling rate associated with those portions of the sidewall 20. In another instance, the controller 60 may determine that the temperature within a portion of the electrolytic cell 1 is relatively low and/or determine that the heat flux associated with a portion of the sidewall 20 is relatively high. In turn, the controller 60 may send an appropriate signal to valve(s) 68 interconnected to the nozzle(s) 36 to decrease coolant flow rates to the nozzle(s) 36, thereby decreasing the cooling rate associated with those portions of the sidewall 20.
The coolant discharge rate from the nozzle(s) 36 may be controlled individually, in sets, or globally by the controller 60 to achieve the desired cooling rates. For example, the controller 60 may selectively control individual nozzle(s) 36 to achieve the desired cooling rates (e.g., via valves located within the nozzle(s) 36, the flow meter(s) 62, and/or the passageway(s) 40). In one embodiment, the controller 60 may be adapted to provide analog-like control of the coolant flow rate, thereby selectively tailoring coolant flow to the nozzle(s) 36, and possibly over a wide range of coolant flow rates. This analog-like control may be accomplished, for example, by moving a valve position between, and sometimes from, various open and closed configurations. In an alternate embodiment, the controller 60 may be adapted to turn coolant flow on and off, in essence providing digital-like control of individual nozzle(s) 36 (e.g., via opening and closing of a valve). As discussed in further detail below, the controller 60 may also/alternatively be interconnected to the nozzle(s) 36 to control the discharge trajectory of the coolant to facilitate selective cooling of various portions of the sidewall 20. The controller 60 may control the nozzle(s) 36 in sets, such as a first and second set of nozzles, to achieve the desired cooling, such as by simultaneously coordinating flow rates and positions associated with a certain set(s) of nozzles. The controller 60 may control individual nozzles in serial or parallel and/or the controller 60 may control sets of nozzles in serial or in parallel.
Any suitable number of nozzle(s) 36 may be employed in accordance with the present invention. The number of nozzle(s) 36 employed in an electrolytic cell 1 is a function of many variables, including, by way of example, coolant delivery rate per nozzle, cell operating temperature, cell size, coolant type and nozzle spacing.
The nozzle(s) 36 may be any suitable nozzles adapted to deliver fluid coolant to sidewalls of an electrolysis cell. In this regard, the nozzle(s) 36 should be resistant to oxidation and should function in relatively high temperatures (e.g., 500° C.-1100° C.). For example, the nozzle(s) 36 may include one or more stainless steel materials. Suitable nozzles include air nozzles produced by, for example, AiRTX, Cincinnati, Ohio, United States of America; EXAIR, Cincinnati, Ohio, United States of America; SILVENT, Bor{dot over (a)}s, Sweden; and Spraying Systems Co., Carol Stream, Ill., United States of America, to name a few.
The nozzle(s) 36 should be adapted to provide coolant to the sidewall 20 at desired flow rates to achieve desired cooling rates. The desired flow rate is generally dependent upon many variables, including cell operating temperature, nozzle number and spacing, coolant type, and cell size, to name a few. For example, nozzles adapted to provide air to the sidewall of an aluminum electrolysis cell may have the ability to provide between 0-50 SCFM or even 0-100 SCFM of air.
The nozzle(s) 36 may be adapted to discharge the coolant in any desired pattern and any desired trajectory. For example, the nozzle(s) 36 may be adapted to discharge coolant in a flat, substantially planar discharge pattern. Alternatively, the nozzle(s) 36 may be adapted to discharge coolant in a non-planar pattern, such as a cone pattern.
The nozzle(s) 36 may be of any shape that facilitates selective cooling of the sidewalls 20. For example, and with reference to
One particular arrangement associated with the nozzles of
Referring back to
The nozzle(s) 36 may be dispersed throughout the electrolytic cell 1 as necessary to facilitate cooling operations. As noted above, the amount of nozzle(s) 36 and the spacing of the nozzle(s) 36 within the electrolytic cell 1 is dependent on various factors. In some instances, it may be desirable to uniformly space the nozzle(s) 36 about an internal perimeter of the outer wall 10, such as uniformly in the latitudinal and/or longitudinal directions relative to the interior perimeter of the outer shell 10. In such an embodiment, the amount of nozzle(s) 36 required to achieve desired cooling rates may be reduced. Likewise, the amount of coolant necessary to achieve the desired cooling rates may also be reduced. Moreover, in such an arrangement, coolant distribution relative to the sidewall will be at most partially overlapping, and in some instances, substantially non-overlapping. Thus, cooling rates of the various portions of the sidewall 20 may be selectively tailored per nozzle and/or nozzle set.
One nozzle(s) 36 arrangement is now described with reference to
In the illustrated embodiment of
Other nozzle arrangements are also possible. For example, a first set of nozzles may be located in a first vertical plane and a second set of nozzles may be located in a second vertical plane. In this arrangement, the first and second vertical planes may be transverse to one another (e.g., in a cylindrical-style electrolytic cell) or the first and second vertical planes may be substantially parallel or perpendicular to one another (e.g., in a rectangular solid-style electrolytic cell). In this arrangement, the first set of nozzles may discharge coolant along a first longitudinal portion of the sidewall 20 and the second set of nozzles may discharge coolant along a second longitudinal portion of the sidewall 20.
As noted, the sidewall thermally interacts with the coolant from the nozzle(s) 36 to facilitate maintenance of ledge 8 profile. In this regard, the sidewall 20 should generally be adapted to facilitate thermal interaction between the coolant and the ledge 8. Thus, the sidewall 20 may include one or more metal layers adapted to promote heat transfer through the sidewall 20. The sidewall 20 should also be adapted to contain the molten bath and molten metal within the cell. Thus, the sidewall 20 generally comprises one or more impermeable layers adapted to contain the molten bath and molten metal.
One particular sidewall embodiment is illustrated in
Any suitable thermally conductive material may be included in the thermally conductive layer 722, such as metal-containing materials. Likewise, any suitable containment material may be included in the containment layer 724. For example, in aluminum electrolysis cells, the thermally conductive layer 722 may comprise a nickel alloy, such as INCONEL and/or a steel material (e.g., stainless steel), and the containment layer 724 may comprise a castable refractory and corresponding refractory paper.
The outer shell may include any material(s) adapted to contain molten materials in case the sidewall ruptures. One outer shell useful in conjunction with the present invention is illustrated in
Referring back to
Referring now to
The coolant may be any coolant that will facilitate cooling of the sidewall 20. For example, gas phase coolants, such as air, nitrogen, carbon dioxide, or noble gases (e.g., helium) may be used. Liquid phase coolants, such as water, brines, glycols (e.g., propylene glycol, ethylene glycol), calcium chloride, potassium formate, cryogenic fluids, and/or fluorocarbon coolants may also /alternatively be used. The coolants may be pressurized or at atmospheric, or about atmospheric, pressure.
In one embodiment, the coolant comprises air distributed to the nozzle(s) 36 via inlet manifold 32. After use, the air may exit gap 38 to outlet manifold 34 via passageway 42. The outlet manifold 34 may be interconnected to a coolant reclamation system and/or a coolant disposal system (e.g., a vent). In one embodiment, the coolant reclamation system may comprise a heat exchanger. The heat exchanger may be utilized for many purposes, such as for heating water to steam, where the steam is utilized in a turbine application to generate electricity. The heat exchanger could also be used to supply hot air to residential customers for heating applications or cooling applications (e.g., air conditioning or heat pump applications).
The inlet manifold 32 may be configured into any suitable manner to provide coolant to the nozzle(s) 36. For example, and with reference to
The coolant supply may be interconnected to a single electrolysis cell or a plurality of electrolysis cells. For example, and with reference to
In another arrangement, a simple passageway may be utilized to supply coolant to the gap 38. For example, the outer shell may include one or more passageways that fluidly interconnect the gap 38 to an exterior portion of the outer shell 10. Thus, air and/or other fluids located on the exterior of the outer shell 10 may be drawn into gap 38 via such passageways to provide further cooling (e.g., via convection forces from incoming coolant from the nozzles 36).
The present invention also relates to methods of cooling electrolysis cells. For example, and with reference to
With reference to
In view of the foregoing, it will be appreciated that the present invention provides sidewall cooling systems that greatly enhance the ability to control the temperature and thus the profile of the ledge. Moreover, the use of the dual wall system may greatly decreases the outside surface temperature of the electrolysis cell. Indeed, the gap between the sidewall and outer shell will not only serve to cool the sidewall, but the outer shell will generally be much cooler than in traditional electrolysis cells. For example, the outer surface of a traditional aluminum electrolysis cell can reach temperatures in excess of 200° C. With the present invention, the temperature of an outside portion of the outer shell may be well below 200° C., such as not greater than 100° C., even not greater than 75° C., or even not greater than 50° C. In some instances, the temperature of an outside portion of the outer shell may be not greater than 45° C. or even not greater than 40° C. Thus, substantial safety and operational environment advantages may be achieved.
It may be appreciated that, while the above embodiments have been described in reference to nozzles, jets may also be used in place of nozzles, as appropriate. Moreover, neither nozzles nor jets may be utilized in accordance with the present invention. For instances, coolant may be passed from an inlet manifold through one or more inlet passageways located in the outer shell, through the gap and to the sidewall without the use of a nozzle and/or jet. One or more outlet passageway(s) may be fluidly interconnected to the gap to receive the discharged coolant, the outlet passageway(s) being fluidly interconnectable to the exterior of the outer shell, a coolant reclamation system and/or or a coolant disposal system. The passageways may be in the form of an insert (e.g., a pipe), or may be integral with the outer shell (e.g., such as by drilling holes in the outer shell). As may be appreciated, a mixture of nozzles, jets and/or passageways may be use in accordance with the present invention.
It will be appreciated that, while the present invention has been described and depicted in relation to a cylindrical style electrolysis cell, other electrolysis cell arrangements may be used. For instance, the electrolysis cell may be of a rectangular solid configuration, wherein the outer shell comprises two opposing walls of the rectangular solid and end walls comprise the other two opposing walls of the rectangular solid. Two sidewalls may be disposed inside the cell relative to and coincidental with the two outer shell walls, thereby defining the gaps. Sidewalls may or may not be used coincidental with the end walls. Any of the above-described nozzle, manifold, and other features may be used in conjunction with this arrangement. In some instances, this rectangular solid electrolysis cell arrangement may be preferred relative to the cylindrical electrolysis cell arrangement. The cooling systems and methods of the present invention may be utilized with various electrolysis cells including, without limitation, aluminum, lead, magnesium, zinc, zirconium, titanium and silicon electrolysis cells.
While various approaches, aspects, embodiments and otherwise of the present invention have been described in detail, it is apparent that modifications and adaptations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of present invention. Moreover, the use of directional and/or positional terms, such as upper, lower, middle, horizontal, vertical, exterior, interior, latitudinal, longitudinal, above and/or below, and the like, are for illustrative purposes and should not be construed as limiting the invention in any manner.
This application claims priority to U.S. Provisional Application No. 60/820,219, filed Jul. 24, 2006, entitled “SIDEWALL TEMPERATURE CONTROL SYSTEMS AND METHODS AND IMPROVED ELECTROLYSIS CELLS RELATING TO SAME”, which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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60820219 | Jul 2006 | US |