High-length isotope separation column and assembly method

Abstract

The present invention relates to the field of distillation of isotopes by means of distillation columns. It is an object of the present invention to describe an innovative distillation column providing a significant improvement to the prior art. In particular, the distillation column will be a modular column with the innovative idea of any height required.

Description

[0001] This application is a divisional application of the application filed on April 13, 2018, with application number 201880024935.X (international application number PCT / IB2018 / 052581) entitled "Long-length isotope separation column and assembly method". Technical Field

[0002] This invention relates to the field of isotope separation, and, specifically, to a method based on separation by distillation in a very tall column. In particular, the invention describes an innovative column constructed from several modules connected in series, installed in a mine or adaptable structure and adapted to be supported by the mine or adaptable structure, thereby achieving new technological results in this field. Background Technology

[0003] The number of neutrons in an atomic nucleus varies among isotopes of chemical elements. The number of protons (and therefore electrons) is the same, and the chemical bonds of isotopes are also the same. Isotope separation relies on subtle differences in chemophysical properties influenced by the mass differences between isotopes.

[0004] Among the various methods used for isotope separation, continuous fractionation, which is generally carried out at low temperatures (and is often called cryogenic distillation), is a known technique for isotope separation of atoms and molecules of light elements.

[0005] In continuous fractionation, the feed (gas or liquid) is fed into a distillation column under flow control; the column is filled with distillation plates and / or structured packing (with liquid redistribution plates if necessary), designed to maximize contact between the upward-flowing vapor stream and the downward-flowing liquid stream. At the top of the column, a condenser cools and condenses the upward-flowing vapor stream, creating a downward-flowing liquid stream that falls from the top to the bottom under gravity; at the bottom of the column, the liquid stream boils in a reboiler, creating an upward-flowing vapor stream, driven by the pressure difference generated by the vapor condensation at the top condenser, flowing from the bottom to the top of the column. Continuous fractionation allows for the separation of substances or their components using its selective evaporation. Substances with lower vapor tension concentrate at the bottom of the column; substances with higher vapor tension concentrate in the top condenser; during processing, a slipstream of the separated substances can be extracted from the top condenser and from the bottom reboiler.

[0006] When used for isotope separation, continuous fractionation concentrates heavy isotopes at the bottom of the column (i.e., those characterized by lower vapor pressure) and light isotopes at the top of the column (characterized by higher vapor pressure).

[0007] The most important parameter for determining the achievable rate and purity of isotope separation in a distillation column is the ratio α(T) of the element's vapor pressure, which depends on the operating temperature T. For isotope separation via distillation, the ratio α is generally very close to one (the number 1), with a very small difference (α-1), typically on the order of parts per thousand to parts per ten thousand, and is almost constant over a small temperature range in which the column operates, generally chosen near the standard boiling point of the fluid.

[0008] The small difference (α-1) determines the minimum number of equilibrium stages required for effective separation in a distillation column. The so-called "Fenske's Law" indicates that the minimum number of stages required for effective separation is 1 / ln(α) ≈ 1 / (α-1): this means that the required number of equilibrium stages for isotope separation is extremely large, ranging from hundreds to tens of thousands.

[0009] Small differences (α-1) also severely limit the production rate and determine the energy required for separation: for systems with theoretical orders near the theoretical minimum set by Fenske's law, the reflux ratio is also on the order of 1 / ln(α) ≈ 1 / (α-1), which is defined as the ratio of the liquid mass flow rate in the column to the distillation mass flow rate, i.e., the ratio of the mass flow rate of the vapor condensed at the top condenser and returned to the column to the mass flow rate of the vapor condensed at the top condenser and extracted as distillate. This means that the fraction of recondensed vapor that can be extracted as a useful product is minimized; it also means that a large amount of energy is required to recondense the vapor to form a very large downward flow of liquid; and it also means that an equally large amount of energy is required to boil the liquid at the bottom of the column to produce a very large upward flow of vapor.

[0010] Therefore, in order to effectively utilize continuous cryogenic fractionation, it is desirable to use extremely tall columns, ranging from hundreds to thousands of meters in height, thus accommodating thousands to hundreds of thousands of equilibrium stages; it is also desirable to use columns with very large diameters, ranging from tens of centimeters to several meters, capable of supporting the required very large upward flow of vapor and downward flow of liquid without causing the problem of column "overflow," which hinders the very efficient equilibrium between the vapor and liquid phases required for effective isotope separation.

[0011] Please note that in known prior art, cryogenic distillation columns at least include an internal distillation column, which is self-supporting and isolated by passive insulation materials or within a cryostat, i.e., a self-supporting vessel operating under vacuum, with the internal processing column encased in multilayer insulation (MLI) to minimize heat transfer. It is impossible to construct a self-supporting column suitable for cryogenic distillation and reaching the required height of several hundred meters or more.

[0012] The construction, commissioning, and operation of extremely tall columns, some several meters in diameter, necessitate switching to expensive mechanical structures for support. The cost of these mechanical structures increases with height far more rapidly than the cost of the columns they support. For this reason, the tallest known distillation columns do not exceed 60-70 meters in height.

[0013] Furthermore, when the required height of several hundred meters is achieved due to the innovative technology of this invention, the large fluctuations between room temperature and the processing operating temperature of the cryogenic distillation column are expected to cause the net thermal shrinkage of the column from a fraction of a meter to several meters. At the same time, due to the limited temperature fluctuations of the ambient temperature, the surrounding container is subject to limited thermal expansion and / or contraction.

[0014] Examples of prior art with the aforementioned problems can be found in the description of GB 525,575, a document from 1940, which describes towers (i.e., contact towers, condensers, and bubble towers) used in chemical processing, in which the weight of the tower is elastically supported at spatial intervals throughout its height. The tower comprises a series of stacked bubble or contact support elements, some or all of which are supported at intervals by springs across the height of the tower, directly or through the outer casing. The tower is formed from a uniform portion 2 of ferrosilicon. A pot or metal support with a conical flared end is secured by clamping rings, some of which are eye bolts, engaged by hooks on helical compression springs anchored to brackets supported on an external steel frame. An alternative portion has an inner perimeter flange engaged on the inner contactor bubble element via an outer perimeter flange. Furthermore, by providing elastic support means, the weight distribution of the tower becomes continuous as the tower expands or contracts due to fluctuating temperature conditions during use.

[0015] It will be immediately apparent to those skilled in the art that such installation is very expensive and the height cannot be increased indefinitely; such installation can only reach a reasonable height of 100 meters, and furthermore, there is no insulation, which contradicts the fundamental purpose of this invention to operate the column as a cryogenic distillation column. Furthermore, the method of supporting the column by springs cannot compensate for the expansion or contraction of the column, which is several meters high, required for operation as a cryogenic distillation column.

[0016] Document EP 0913655 of 1999 describes a method for constructing a large-scale elongated inner structure surrounded by an outer structure, the inner structure being a fluid-containing structure for forming at least a portion of the fluid supply installation, as the applicant himself states: "The invention is more particularly applicable to the construction of air distillation columns, which can reach heights of up to 60 meters, surrounded by their supporting frames," thus differing from one and more objectives of the invention and being a further example of the limitations of the prior art cited above. The present invention aims to provide a method for constructing a large inner structure surrounded by an outer structure, allowing for rapid on-site assembly in response to the vertical stress of the column, and also allowing for pre-assembly in the workshop prior to on-site transport. The procedure uses modules, each module being made from a portion of the inner structure 1 enclosed within a portion of the outer structure 5, and assembled laterally to create a column of the required height. The inner and outer structures are assembled together by horizontally inserting each inner structure into the outer structure, e.g., using a system of rollers 11 and tracks 31, after which the two structures are secured together to form a module.

[0017] Before separating these modules; for each module, construction is completed by placing protective metal sheets on the corresponding external structural portion (at least except in the connection areas with other modules); the inner structure is a distillation column; the outer structure is merely a support frame; the modules are assembled sequentially from the lower module to the upper module to erect the inner structure in the field. It will be clear to those skilled in the art that this is merely another example of the construction of a distillation column, which suffers from the disadvantages described herein, particularly the lack of any mention of thermal insulation, any mention of an insulated container, any mention of an insulated container suitable for operation as a cryostat under vacuum, a maximum height of 60 meters, and furthermore, the column is constructed horizontally within the support frame, requiring its vertical lifting once construction is complete. All these features render the method useless for the purposes of this invention. In fact, this invention requires a construction method suitable for supporting columns hundreds or thousands of meters long; this requires the existence of supports already installed along the final vertical direction of the column's positioning, thereby allowing the construction of the column in the final vertical direction and at its final position by cascading the column modules onto said supports. In some preferred embodiments, the present invention is a cryogenic distillation column, requiring the presence of an isolated container that operates as a cryostat under vacuum.

[0018] Therefore, it will be clear to those skilled in the art that the documents cited above do not represent the closest prior art, as the present invention relates to enabling continuous cryogenic fractionation at heights of several hundred meters through the innovative designs and methods described therein. Instead, the results achievable in the art as detailed in the above-cited documents are limited by the aforementioned structural technical problems. Summary of the Invention

[0019] One object of the present invention is to overcome the shortcomings of the prior art.

[0020] In particular, one object of the present invention is to improve the height and diameter of the distillation column in a substantially practical manner.

[0021] Another object of the present invention is to describe a low-temperature distillation column.

[0022] Another object of the present invention is to describe a novel distillation column for isotope distillation to obtain new results in isotope separation.

[0023] A further object of the present invention is to describe a novel distillation column that allows the aforementioned results to be achieved at a reasonable and affordable construction cost.

[0024] Another object of the present invention is to describe a novel distillation column that is practical for construction, the modules of which can be built in a workshop and easily transported to the field, where they are assembled in their final positions (and, if necessary, disassembled for maintenance or other reasons).

[0025] Another object of the present invention is to describe a novel distillation column that can adapt to its own thermal expansion or contraction and the resulting stress.

[0026] Therefore, another object of the present invention is to describe a novel distillation column that is practical for repair in the event of damage, is easily accessible, and whose constituent elements can be easily replaced.

[0027] Another objective of this invention is to improve the energy performance of distillation.

[0028] Finally, another object of the present invention is to describe a novel distillation column that allows isotopes to be obtained by cryogenic distillation at a more affordable cost.

[0029] This and further objectives of the invention will be advantageously achieved by constructing an innovative column for isotope distillation, the innovative column comprising at least a large number of separate modules, which may be less or more tall; in particular, in a very innovative manner, the object of the invention describes an innovative cryogenic distillation column and a method of assembling the column, the column comprising at least a bottom reboiler, a top condenser and a central column portion, the central column portion comprising at least one or more central modular elements, the modular elements being connected to the wall of a supporting structure by means of connection, the column being characterized in that one or more modules comprise at least one or more bellows for compensating for the thermal expansion or contraction of the column modules by the contraction or expansion of the bellows along the total height of the column.

[0030] In a further preferred embodiment, the module is surrounded by insulating material.

[0031] In a further preferred embodiment, the module includes at least an insulating container element and at least one internal modular column element surrounding the container element. The volume between the thermally insulating container and the internal column element is maintained under vacuum, while the column element is wrapped with multiple layers of insulation, or may be filled with an insulating material suitable for operation of a column for cryogenic distillation, thereby minimizing heat transfer and minimizing the impact of large temperature variations of the internal modular element on the external container element. Therefore, the innovative modular distillation column can operate as a cryogenic distillation column at low temperatures.

[0032] In a preferred embodiment of the invention, one or more of the external insulation container elements further include bellows, that is, a portion of the container is replaced by one or more bellows to compensate for thermal expansion or contraction caused by changes in ambient temperature, thereby maintaining a constant total height of the external insulation container between its top and bottom supports. The presence of bellows in the external insulation container also ensures that the weight of each individual module is transferred to the corresponding supports of the support structure.

[0033] In a further preferred embodiment of the invention, at least one isolation container contains a plurality of distillation column elements, which operate in parallel and / or are connected in series.

[0034] Therefore, in a particularly preferred embodiment, the at least one internal column element is structurally connected to the external container element at one point or not by means of a fixed connection, while the portions of the column and container other than the connection are released and freely slide relative to each other in the axial direction. Thus, when the at least one internal column element is subjected to significant thermal expansion or contraction in the vertical direction during processing operations, the external container is not subjected to mechanical stress due to this expansion or contraction of the internal column element.

[0035] In particular, in some preferred embodiments, the at least one outer container element and the at least one inner column element are connected at one point or not by means of a fixed connection, and are connected at more than one point by means of a sliding joint, sliding strut, link, or other means that allow limited and minimal adjustment of the positioning of the inner column element relative to the outer container element in the axial direction. Thus, the portions of at least one container and inner column element not connected by a fixed means are free to slide in the axial direction to locally compensate for the thermal expansion or contraction of any of its portions within the height of the module.

[0036] Regarding the assembly method for this innovative cryogenic distillation column, in particular, in a preferred embodiment, the module forming the column is installed inside a mine, which is only one possible embodiment of the invention: for the scope of the invention, a support tower or similar structure may also be used if it is high enough, which does not limit the scope of the invention.

[0037] This invention allows for the design and construction of columns of unprecedented size, ranging in height from hundreds of meters to thousands of meters and in diameter from a few centimeters to a few meters, to be installed within a mine or adaptable structure and supported by said mine / tower, preferably consisting of a bottom reboiler, a top condenser and a central column portion, advantageously achieved through more than one innovative central module.

[0038] In a very convenient manner, the mine shaft will serve as a support structure; in fact, in a preferred embodiment of the invention, the structure conveniently acts as a support frame for the distillation column, thereby avoiding the necessity of constructing a large and unsustainable, expensive structure on the ground. Note that in any further embodiment, other similar support structures may be used to secure and support modular elements of the innovative column for isotope distillation in other locations, provided that such structures would fit within the scope of the invention, which does not limit the scope of the invention.

[0039] Therefore, in the preferred embodiment described herein, several modules for constructing the innovative column will be fixed to the mine wall to support the individual modules, thereby enabling the construction of columns reaching heights of several kilometers and diameters of several meters. Ideally, and advantageously, the modules of the column will each have an individual height ranging from several meters to tens of meters, so that they can be easily transported from the construction site (where they are constructed and tested) to the mine (where they are finally assembled).

[0040] In this way, the final assembly steps are conveniently minimized, and it essentially consists of only connections between the module series, which are stacked in series one to another within the mine, with the connections conveniently made only when the modules are installed in their final positions. (Another way in which the modules can be assembled will be described below with reference to the detailed description of the accompanying drawings associated with at least one preferred embodiment of the invention).

[0041] The construction of the new modular column will be derived from the serial assembly of modules from the bottom to the top of the mine.

[0042] Please note that, obviously, the realization of a distillation column for isotopes conceived in a modular pattern is not merely a matter of dividing a known distillation column into individual modular elements, such as the column described above: In this invention, numerous physical aspects have been considered to achieve an innovative modular column that will overcome all the technical shortcomings described.

[0043] Therefore, upon receiving the assembly at the site, the modules are lowered into the mine using a shaft; they are brought to the required positions for connection to other modules that have been parted in a predetermined sequence; they are advantageously fixed to the mine wall and surrounding rock, for example, by first connecting to a platform, which in turn is fixed to a structural plate, which is fixed to the shaft wall or mine wall, directly or by other structural elements, by means of rock bolts or other types of connections to the shaft wall or to the rock surrounding the shaft wall, including by tenon joints fixed to mortises recessed into the shaft wall or rock.

[0044] Therefore, when the module is placed in its final position, the weight of any module is transferred to the mine and the surrounding rock; then the modules are connected to the already installed modules by welding or flange connection, and the construction of the high distillation column is carried out in series.

[0045] Therefore, some of the innovative elements introduced in this invention are: a new connection between the column element and the well wall, for directly securing the structural support of each module through the well wall and surrounding rock; within the body of each module, there is an expandable / contractable section, innovatively achieved by introducing bellows or other expandable / contractable materials, capable of compensating for the significant vertical thermal expansion or contraction that the column may cause during the cycles of construction, commissioning, and especially operation: for columns hundreds of meters high undergoing thermal transitions between room temperature and low temperatures up to 300 Kelvin, the expansion and contraction of the non-expandable / contractable section can reach several meters, which must be compensated for by the adaptation of the expandable / contractable section in length. Thus, this is quite different from GB525,575, in which the expansion or contraction of the distillation column is offset by the compression or extension of springs connected to the supports of the column itself. In this invention, the expansion or contraction of the distillation column is compensated by the contraction or expansion of a bellows, which is essentially part of the module of the distillation column (and the surrounding insulating container), maintaining a constant total vertical length of the column between two extreme supports at its top and bottom. A significant advantage of this invention is that the construction method is suitable for constructing extremely tall columns. Conversely, the method described in GB525,575 is unsuitable for constructing columns exceeding 100 meters in height because, when the column is operated at low temperatures, the cumulative deformation from top to bottom results in a contraction on the order of meters, which is impractical to compensate for using springs. In particular, note that, considering the specific arrangement of the springs used in the invention described in GB525,575, these springs are only useful for compensating for thermal expansion when moving from room temperature to the processing operating temperature (with the limitations and problems described above), but they are not useful for compensating for thermal contraction, which is the central problem addressed by this invention as a distillation column, and more specifically, for low-temperature distillation columns, particularly when moving from room temperature to the processing operating temperature, which are subject to thermal contraction.

[0046] Therefore, in particular, the present invention solves the aforementioned and other known problems by means of the innovative use of the bellows, which will be further described in the accompanying drawings.

[0047] It is well known that mine shafts with a total vertical height of several hundred to several thousand meters and a diameter of several meters are readily available. The innovative column and method described in this invention allow for the construction of an unprecedented number of distillation columns by connecting a large number of modules of the novel concept in series, each module supported by the mine wall and surrounding rock. The number of stages is directly proportional to the total available height, with each theoretical stage ranging from several centimeters to tens of centimeters in height. Advantageously, the total number of stages achievable using this modular column ranges from several thousand to hundreds of thousands.

[0048] The new modular column concept also offers the possibility of constructing large-diameter column elements, ranging from tens of centimeters to several meters, allowing for substantial improvements in isotope separation rates and isotope purity.

[0049] In one embodiment, the distillation column comprises a hollow body with an inner cylindrical wall filled with distillation plates and / or structured packing.

[0050] In a particular preferred embodiment, the distillation column is surrounded by a thermal insulation layer.

[0051] In one embodiment, the thermal insulation layer can be obtained by utilizing a structurally thermally insulated container surrounding the distillation column.

[0052] In one embodiment, the gap between the inner surface of the thermally insulating container and the outer surface of the distillation column is filled with an insulating material.

[0053] In one embodiment, the insulating material is, in particular, expanded perlite, which, due to its high porosity, also provides exceptional lightness. Expanded perlite possesses exceptional thermal insulation capabilities and guarantees very low thermal conductivity at all temperatures. Due to its low cost, ease of installation, non-flammability, and reduced tendency to retain moisture, it has found significant applications in cryogenic industries requiring supercooled gas performance, demonstrating numerous advantages in its application and use.

[0054] In one embodiment, the outer surface of the internal distillation column is covered by multiple layers of insulation, and the volume between the inner surface of the thermally insulating container and the outer surface of the distillation column is maintained under vacuum, below 10. -2 Under a pressure of mbar, the internal distillation column is operated within a cryostat.

[0055] In one embodiment, advantageously, the thermally insulated container contains a plurality of distillation column elements that can operate in parallel and / or can be connected in series, with the top of one column bound to the bottom of a subsequent column by a processing line constructed inside or outside the thermally insulated container, in the latter case with independent thermal insulation; in the parallel configuration, the columns can operate together or independently of each other.

[0056] In one embodiment, initially, the column is constructed from a number of vertical modular parts, which are then connected to other vertical parts via flanges or welded joints.

[0057] In one embodiment, the modular thermal insulation container is constructed from a number of vertical sections, which are in turn connected to other vertical sections of the thermal insulation container via flanges or welded joints.

[0058] In an advantageous embodiment, each or several of the vertical portions forming the internal column, or the combination of the internal column and the surrounding thermal insulation container, is equipped with one or more bellows to allow compensation for the significant thermal expansion or contraction of the column in the vertical direction during installation, especially during handling operations.

[0059] The objective of this invention is to improve the energy performance of distillation by innovatively introducing an economical energy recovery loop. The cooling power at the top condenser and the heating power at the bottom reboiler are distributed through two heat exchangers. A single closed loop containing a heat exchange fluid exists, which is used as a refrigerant at the top condenser heat exchanger to provide the cooling power required to condense the upstream gas flow reaching the top condenser into a liquid phase; and it is also used as a heating fluid at the bottom reboiler heat exchanger to provide the heating power required for the liquid phase of the fluid boiling for distillation. Note that the use of a single fluid for heat exchange is also novel.

[0060] In one embodiment, distillation is carried out at a low temperature, and the fluid used as the refrigerant fluid at the condenser and the heating fluid at the reboiler is nitrogen: in a closed loop, nitrogen is circulated from the reboiler back to the condenser and from the condenser back to the reboiler; in liquid form, nitrogen is fed into the heat exchanger at the top condenser, where the evaporation of liquid nitrogen provides the cooling power required for the condensation of the upstream gaseous flow; a nitrogen recirculation compressor increases the pressure of the gaseous nitrogen discharged from the top condenser heat exchanger and sends it to the bottom reboiler; at the bottom reboiler, gaseous nitrogen enters the bottom condenser heat exchanger; at the bottom reboiler, the pressurized nitrogen releases heating power, immediately forcing the liquid reflux flow of the distilled fluid to boil and forcing the nitrogen condensed into a liquid phase to exchange for the cooling of the fluid; finally, to complete the closed loop, the nitrogen liquefied in the bottom condenser heat exchanger is pumped towards the top condenser heat exchanger via a thermally insulated line by a cryogenic pump.

[0061] In one embodiment, a heat-insulated line for transporting liquid nitrogen from bottom to top in a heat exchanger is contained within a heat-insulated container in a column. In another embodiment, a heat-insulated line for transporting gaseous nitrogen from top to bottom in a heat exchanger is contained within a heat-insulated container in a column. Note that using nitrogen as a single fluid for heat exchange is also novel.

[0062] In another novel embodiment of cryogenic distillation, nitrogen is replaced by an inert rare element (such as argon, krypton, or xenon) as the refrigerant fluid, allowing for an extended range of operating temperatures. This is simply the use of another element in the same hydraulic circuit, characterized by different ranges of pressure-dependent temperatures for the phase transition between the liquid and gaseous phases of said element. Note that the use of argon, krypton, or xenon as a single fluid for heat exchange is also novel.

[0063] The unprecedented size and height of the previously cited modular column concept allow for the number of orders necessary to separate argon and xenon isotopes, ranging from thousands to hundreds of thousands. For argon isotopes (such as...) 36 Ar、 38 Ar、 39 Ar and 40 The difference between Ar and the volatile ratio (α-1) is on the order of a few parts per thousand. 39 Ar depletion 40 Ar is of particular interest as a target for the study of very large-scale (several tons to hundreds of tons) dark matter. Due to the previously introduced "Fenske's Law", the minimum order required for effective separation is 1 / ln(α) ≈ 1 / (α-1). This means that the equilibrium order required for isotope separation is extremely large, ranging from hundreds to tens of thousands.

[0064] The separation of argon isotopes requires operation at low temperatures near the standard boiling point of argon (around 87 Kelvin), and operation of the distillation column within a cryostat. Due to the small value of (α-1), the minimum production rate of a few kg / day for isotope enrichment of argon isotopes requires very high vapor flow rates (hundreds of standard m³ / h). 3 (on the order of magnitude of) and very high liquid flow rates (in the order of several m³ / h) 3 (On the order of magnitude). Using columns with a minimum diameter of tens of centimeters, the desired steam and liquid flow rates can be achieved. Equipped with structured packing, it can maintain significant liquid and steam flow rates while maintaining excellent surface coverage without overflow. This can be achieved using columns preferably having 10... -15 Theoretical plate height (HETP) in centimeters or more and several meters 3 / (m 2 The packing achieves a maximum liquid velocity (× hours). These considerations drive the selection of minimum height for internal columns of several hundred meters and minimum diameter for internal columns of several tens of centimeters. Enclosing ultra-insulated and several processing lines of thermally insulated containers can easily achieve diameters of several tens of centimeters.

[0065] Using mines to install modular cryogenic distillation columns allows for sizes exceeding those required for applications necessary for argon isotope production. Modular cryogenic distillation columns can be adapted to existing mines, reaching diameters of several meters and heights of several kilometers. This makes it possible to use these columns even for the separation of xenon isotopes, with (α-1) values ​​on the order of tens of thousands of parts per ten thousand, a level lower than those used for argon isotopes. This is in contrast to xenon isotopes depleted in other xenon isotopes. 136 Xe is of particular interest as a target for very large-scale experiments, ranging from a few tons to hundreds of tons, for the study of extremely rare and unobserved nuclear decay modes (known as "neutrinoless double beta decay").

[0066] This invention will enable, in a highly advantageous manner, the separation of large quantities (greater than several kg / day) of argon and xenon isotopes.

[0067] At the same time, this invention will significantly improve the ability to produce and manufacture much more affordable light isotopes, as the production of isotopes in much smaller columns via cryogenic distillation is already covered by existing technologies, including but not limited to: 12 C and 13 C is obtained by methods including but not limited to low-temperature distillation of CO; 14 N and 15 N is obtained by methods including but not limited to low-temperature distillation of N2, NO and NH3; 16 O and 18 O is obtained by low-temperature distillation methods including but not limited to H2O, O2, and NO.

[0068] As an example, a 300-meter-high column of 2,500 units with a diameter of approximately 30cm would result in a rate of approximately 10 kg / day, with a single-trip coefficient of 10. 40 Ar stream 39 Ar decreases; similarly, the same column will be directly enriched with an isotopic fraction of 0.995 (99.5%) by distilling CO at a rate of kg / day fraction. 13 C; Similarly, the same column will be directly enriched with an isotopic fraction of 0.995 (99.5%) by distilling NO at a rate of kg / day fraction. 15 N and 18 O. Attached Figure Description

[0069] The advantages and further advantages derived from the innovative low-temperature modular column for isotope distillation described herein will be further described below with reference to non-limiting examples provided in the accompanying drawings for illustrative and non-limiting purposes. These drawings illustrate different aspects and embodiments of the invention, and where appropriate, structures, components, materials, and / or similar elements are indicated by similar reference numerals in different drawings.

[0070] Figure 1 The illustration shows a preferred embodiment of a modular distillation column according to the present invention, which is installed within a mine / support structure and supported by the lateral walls of the mine / support structure; Figure 2 The illustration shows a preferred embodiment of the modular distillation column according to the present invention, which includes an economical heat recovery loop; Figure 3 Refer to the preferred embodiment of the connection and implementation of the various modules of the illustrated column. Detailed Implementation

[0071] Although the present invention is readily subject to various modifications and alternative constructions, some of the illustrated embodiments are shown in the accompanying drawings, which will be described in detail below.

[0072] However, it must be understood that the invention is not intended to be limited to the specific embodiments illustrated, but rather, the invention is intended to cover all modifications, alternative constructions and equivalents that fall within the scope of the invention as defined in the claims.

[0073] Unless otherwise specified, the words “such as,” “etc.”, and “or” are used to indicate non-exclusive alternatives without limitation.

[0074] Unless otherwise specified, the word “including” means “includes but is not limited to”.

[0075] Figure 1The illustration shows a simplified preferred embodiment of the innovative modular distillation column 100, comprising a support system 7 installed within a mine shaft 2 defined by surrounding rock 1. In this embodiment, the complete modular distillation column 100 includes a condenser 3, a reboiler 4, and one or more central modules 5, ..., 5n. Advantageously, each central module 5 is equipped with more than one bellows 6 to compensate for the vertical thermal expansion or contraction of the modular column 100 due to large fluctuations between room temperature and processing operating temperature.

[0076] Utilizing this innovative construction, due to the bellows contained in the modules, the final height of the column between the top and bottom supports always remains the same, regardless of any large temperature fluctuations between room temperature and the processing operating temperature. This is because as one or more modules of the column expand due to temperature increases, the change in height is compensated by the contraction of the bellows contained in said modules (or, and other modules), and when the modules contract due to temperature decreases, the change in height is compensated by the expansion of the bellows. Thus, it is highly advantageous to maintain the same height of the column and preserve its integrity under different operating conditions. At the same time, in a highly innovative and advantageous manner, it allows for the construction of columns of any required height, even exceeding 100 meters.

[0077] Some or all of the vertical modules 5 are connected to the well wall. In one embodiment, the vertical modules 5 are attached to the well wall by a mechanical support system 7, which includes, for example, brackets or structural supports. Figure 3 As shown in the figure, the bracket or structural support is secured to the well wall by rock bolts 31 or other types of connections to the well wall or to the rock surrounding the well wall (including, by tenon joints fixed to mortises recessed into the well wall or rock).

[0078] Please note that in Figure 1 The diagram illustrates a simplified embodiment of the invention, in which the modular element 5 is directly connected to the wellbore.

[0079] In a further embodiment, the vertical module 5 is mounted on the platform 29, providing partial access to the column 100, which is attached to the well wall via a mechanical bracket, which is in turn secured to the well wall by rock bolts 31 or other means described above. The well wall may be exposed rock, or it may be covered with a layer of concrete, reinforced concrete, brick, or other means suitable for this purpose.

[0080] In one embodiment, the condenser and / or reboiler are also secured to the wellbore by a mechanical bracket, which in turn is secured to the wellbore by rock bolts or other means.

[0081] In one embodiment, the condenser and / or reboiler is also mounted on a platform providing localized access, the platform being secured to the wellbore by rock bolts or other means. In another embodiment, the condenser and / or reboiler includes sections with more than one bellows to compensate for the vertical thermal expansion or contraction of the column.

[0082] Systems with added economical heat exchangers can reduce operating costs by recovering the enthalpy spent and gained at the reboiler and condenser. According to... Figure 2 In one embodiment, distillation is carried out at a cryogenic temperature, and the heat exchange fluid, used as the refrigerant fluid at the condenser and as the heating fluid at the reboiler, is nitrogen or a rare element such as argon or xenon. The heat exchange fluid, as a liquid, is fed to the top condenser heat exchanger 11; the cooling power required by the vapor stream of the fluid separated by distillation in the distillation column in the top condenser heat exchanger 11 is provided by a phase change of the heat exchange fluid from gas to liquid; the gaseous flow of the heat exchange fluid discharged from the top condenser heat exchanger 11 is compressed under high pressure by a gas compressor 12 and sent to the inlet of the bottom reboiler heat exchanger 13; the heating power required by the bottom reboiler heat exchanger 11 to boil the liquid stream of the fluid separated by distillation in the distillation column is provided by a phase change of the heat exchange fluid from gas to liquid; the liquid flow of the heat exchange fluid originating from the bottom condenser heat exchanger 13 is pumped towards the top condenser heat exchanger via a cryogenic pump 14, thereby closing the loop.

[0083] according to Figure 3 In one embodiment, each module 5 of the column 100 includes: at least one external thermal insulation container 22; and at least one internal column element 23, enclosed in multiple layers of insulation ( Figure 3 In the (not shown) section, except for the last part dedicated to welding to other modules 5 (which is in place after welding is performed and covered by multiple layers of insulation, as described below); the gap volume 27 between the volume 24 of the thermal insulation container 22 and the internal column 23 is kept under vacuum; the structural support connecting the thermal insulation container to the internal column is not shown.

[0084] Specifically, each of the modules or modular elements 5…5 n It includes at least an insulating container, which contains surrounding columnar elements 23…23 n Container element 22…22 n .

[0085] Please note that an isolation container 22 may contain more than one internal column element 23, forming independent columns that can work together or independently of each other.

[0086] In a preferred embodiment of the invention, the internal volume 24 of the inner column 23 is a processing volume filled with structured packing and / or distillation plates (and, if necessary, liquid distribution plates). Advantageously, a portion of the isolation container 22 is replaced by more than one bellows 26 to accommodate thermal expansion or contraction; in this embodiment, a portion of the inner column 23 is also replaced by bellows 25 to compensate for thermal expansion or contraction. Note that the bellows 25 plays a crucial role for the inner central distillation column 23, which experiences the greatest thermal offset and thus the greatest expansion or contraction cycles due to the anticipated large temperature fluctuations between room temperature and the processing operating temperature. The bellows 26 may also be introduced into the outer isolation container 22 (as shown herein), or not.

[0087] In this regard, it is noted that the volume 27 between the external thermal insulation container 22 and the internal distillation column 23 can be used to extend service lines (such as two lines forming a closed loop of heat exchange fluid, extending from the top of the column to the bottom). Figure 2 (as shown in the diagram), and also accommodates column feed lines and sensors where necessary. In a preferred embodiment, the bellows is also introduced onto a service line (not shown here), which is placed in the space 27 between the inner column 23 and the outer isolation container 22, outside the inner column and inside the outer isolation container.

[0088] The thermal insulation container 22 is connected to the structural support 28, which in turn is connected to the platform 29, which is then fixed to the structural plate or support 30. The structural plate or support 30 is fixed to the mine wall by rock bolts 31 or other types of connections to the wall or to the rock surrounding the wall (including, by tenon joints fixed to mortises recessed into the wall or rock).

[0089] In another embodiment, the modular element 5 is directly connected to a plate fixed to the mine shaft via rock bolts.

[0090] Utilizing the minimum modular components that are already in place 5 n Module 5 should be located immediately adjacent to the lowest module. n-1 Lowered into well 21 and positioned, thereby allowing top module 5 to be positioned. n-1 Internal column section 23 n_1 It can be soldered up to the lowest module 5 n Internal column section 23 n The solder joint is marked with point 33. Figure 3 To illustrate a simplified embodiment, only module 5 is shown. n (5 is used as an example.) At this point, multiple layers of thermal insulation (not shown) are wrapped around the portion of the inner column that is not yet covered by the insulation container to reduce heat transfer via radiation.

[0091] The outer sleeve 32 is pre-positioned around the outer diameter of the bottom outer insulating container, then raised to the appropriate position and welded to the bottom 22. n And adjacent to the bottom 22 n-1 External isolation container components are used to close the cryostat section using solder joint 34.

[0092] All other inserted or subsequent modular components 51…5 n-2 Will be done in the same or similar way (from 5) n-2 (The reverse order of 51) is fixed until the required operating height of the modular column 100 is reached.

[0093] Please note that the modules can also be fixed together by other adaptation methods or means, which are merely minor variations of the present invention; in this embodiment, considering the significant mechanical stress that the modular elements of the expected column 100 will be subjected to, welding is considered to fix those modules 5. n 5 n-1 5 n-2 The safest method is 52, 51, 5.

[0094] In any case, please note that modular components 51…5 n The connection is very easy and practical. Similarly, if necessary, in case of damage, etc., it is easy and practical to disassemble some modular components for maintenance. This is also an advantage of the present invention, as described elsewhere previously.

[0095] As indicated, the very important and innovative aspects described in this invention actually allow for the construction and development of pillars that achieve all the aforementioned advantages, at least incorporating modules 5…5 n One or more of the modules contain at least one more bellows, which can compensate for the thermal expansion or contraction of the module by the contraction or expansion of the bellows.

[0096] In particular, in a preferred embodiment, the module includes a modular container 22 and a modular element 23 of at least one distillation column, at least one of the modular elements 23 including more than one bellows.

[0097] The at least one external container element 22 and the at least one internal column element 23 are connected at one point or not by means of a fixed connection, and are connected at more than one point by means of a sliding joint, sliding support, chain link or other means that allow adjustment of the positioning of the internal column element relative to the external container element in the axial direction. Thus, the portions of at least one container 22 and the internal column element 23 that are not connected by a fixed means are free to slide in the axial direction to locally compensate for the thermal expansion or contraction of any of their portions within the height of the module 5.

[0098] These and further objects of the present invention are achieved by means of a modular distillation column incorporating the features of the appended claims, which form an integral part of this specification.

[0099] Therefore, the height or diameter of the modular elements, the means of fixing to the well, the functional elements of the distillation modular column, the number of fixing means, and the type of fixing means between modules are all considered to be minor modifications to some implementations of the present invention, and must be considered to be covered by the aforementioned objectives of the present invention, and are better set forth with reference to the appended claims.

[0100] Quote 1. Casanova, C., Fieschi, R. & Terzi, N. Calculation of the vaporpressure ratio of Ne, A, Kr, and Xe isotopes in the solid state. Nuovo Cim. 18, 837–848 (1960). 2. Bigeleisen, J. Statistical Mechanics of Isotope Effects on theThermodynamic Properties of Condensed Systems. J. Chem. Phys. 34, 1485–1493(1961). 3. Boato, G., Casanova, G., Scoles, G. & Vallauri, ME Vapourpressure of isotopic liquids. Nuovo Cim. 20, 87–93 (1961). 4. Fieschi, R. & Terzi, N. Quantum effects in the liquid state bymeans of a phenomenological cell model: The vapor pressure ratio of Ne andAr isotopes. Physica 27, 453–464 (1961). 5. Boato, G., Casanova, G. & Levi, A. Isotope Effect in PhaseEquilibria. J. Chem. Phys. 37, 201–202 (1962). 6. Boato, G., Scoles, G. & Vallauri, M. E. Vapour pressure ofisotopic solids by a steady flow method: Argon between 72 °K and triplepoint. Nuovo Cim. 23, 1041–1053 (1962). 7. Ancona, E., Boato, G. & Casanova, G. Vapour pressure of isotopicliquids. Nuovo Cim. 24, 111–121 (1962). 8. Casanova, G., Levi, A. & Terzi, N. Mean square force in liquidargon and separation factor of isotopes. Physica 30, 937–947 (1964). 9. Rashid, K. & Krouse, H. R. Selenium isotopic fractionation duringreduction to Se 0and H 2Se. Can. J. Chem. 63, 3195–3199 (1985). 10. Mills, T. R. Practical Sulfur Isotope Separation by Distillation.Separ. Sci. Tech. 25, 1919–1930 (1990). 11. Calado, J. C. G., Dias, F. A., Lopes, J. N. C. & Rebelo, L. P. N.Vapor Pressure and Related Thermodynamic Properties of 36Ar. J. Phys. Chem. B104, 8735–8742 (2000). 12. Chialvo, A. A. & Horita, J. Isotopic effect on phase equilibriaof atomic fluids and their mixtures: A direct comparison between molecularsimulation and experiment. J. Chem. Phys. 119, 4458–4467 (2003). 13. Canongia Lopes, J. N., Pádua, A. A. H., Rebelo, L. P. N. &Bigeleisen, J. Calculation of vapor pressure isotope effects in the raregases and their mixtures using an integral equation theory. J. Chem. Phys.118, 5028–5037 (2003). 14. Gligan, M., Dulf, E., Unguresan, M.-L. & Festila, C.Preliminaries Regarding General Modeling of the Cryogenic Distillation withApplication to (13C) Iso-tope Separation. in 1, 155–158 (IEEE, 2006). 15. Oi, T. & Otsubo, A. Revisit to Vapor Pressure Isotope Effects ofWater Studied by Molecular Orbital Calculations. J. Nucl. Sci. Tech. 47, 323–328 (2010). 16. Back, H. O. et al. Depleted Argon from Underground Sources. Phys.Procedia 37, 1105–1112 (2012). 17. Neaga, A. O. et al. A Simplified Mathematical Model Of TheCryogenic Distillation With Application To The 13 C) Isotope Separation Column.AIP Conf. Proc. 1425, 189–192 (2012). 18. Dulf, E.-H., Pop, C.-I. & Dulf, F. Systematic Modeling Of The( 13 C) Isotope Cryogenic Distillation Process. 47, 1234–1240 (2012).

Claims

1. A cryogenic distillation column (100) for isotope separation, with a height exceeding 100 meters, comprising: At least one reboiler (4) located at the bottom of the low-temperature distillation column (100). The condenser (3) is located at the top of the low-temperature distillation column (100). Module element (5) is connected to the wall of the supporting structure via a connecting device, wherein the module element (5) comprises: A plurality of central module elements (5…5n) connected in series with each other, wherein the plurality of central module elements (5…5n) include: At least one insulating container element (22…22n), and At least one internal pillar element (23…23n) is enclosed within the insulating container element (22…22n) to provide thermal insulation for the internal pillar element (23…23n). Multiple bellows (25, 26), connected to a portion of each insulated container element (22…22n) and a portion of each internal column element (23…23n), transfer the weight of each individual central module element (5…5n) to a corresponding individual support in the supporting structure. When one or more central module elements (5…5n) of the cryogenic distillation column (100) expand due to temperature increase, the height change of the cryogenic distillation column (100) is compensated by the contraction of the bellows (25, 26) contained in each central module element (5…5n) of the cryogenic distillation column (100); when one or more central module elements (5…5n) of the cryogenic distillation column (100) contract due to temperature decrease, the height change of the cryogenic distillation column (100) is compensated by the expansion of the bellows (25, 26), thereby allowing the construction of cryogenic distillation columns (100) of predetermined height, even exceeding 100 meters, and maintaining the final height of the cryogenic distillation column (100) between the top support and the bottom support connected to the support structure always the same as the predetermined height.

2. The cryogenic distillation column (100) for isotope separation according to claim 1, wherein, Each portion of the insulated container element (22…22n) and each portion of the internal column element (23…23n) includes a plurality of bellows mounting positions, wherein one or more of the plurality of bellows (25, 26) are adapted to the bellows mounting positions to compensate for the thermal expansion or contraction of the column.

3. The cryogenic distillation column (100) for isotope separation according to claim 1 further comprises: The end portions of two adjacent internal column elements (23…23n) are not enclosed by the at least one insulating container element (22…22n); The ends of the outer diameters of two adjacent insulating container elements (22…22n) An outer sleeve (32) is disposed around the end of the outer diameter of the two adjacent insulating container elements (22…22n). Wherein, the end portions of the two adjacent internal column elements (23) that are not enclosed by the at least one insulating container element (22…22n) are connected to each other by a first weld, and Wherein, after performing the first weld (33), the end portions of the two adjacent inner column elements (23) are wrapped by the at least one insulating container element (22…22n), and After wrapping the at least one insulating container element (22…22n) at the end portion, the outer sleeve (32) is raised to cover the ends of the outer diameters of the two adjacent insulating container elements (22n) and a second weld (34) is performed to close the ends.

4. The cryogenic distillation column (100) for isotope separation according to claim 1, wherein, The at least one external isolation container element (22) and the at least one internal column element (23) are connected by a sliding joint, a sliding support, and a chain link to allow the internal column element to be axially adjusted relative to the external isolation container element, thereby enabling it to slide freely in the axial direction to locally compensate for the thermal expansion or contraction of any of its components within the height range of the module element (5).

5. The cryogenic distillation column (100) for isotope separation according to claim 1, wherein, The at least one external isolation container element (22…22n) and the at least one internal column element (23…23n) are fixedly connected at one or more points.

6. The cryogenic distillation column (100) for isotope separation according to claim 1 further comprises at least one support system (7) having: Structural support (28) which connects to the at least one external insulating container element (22). Platform (29), which is connected to the structural support (28). Structural plate (30), which connects to the platform (29) and is fixed to the mine wall; Rock bolts (31) are used to horizontally connect the structural plate (30) to fix the structural plate (30) to the mine wall, thereby holding at least one of the plurality of central modular elements (5…5n) in the vertical direction.

7. The cryogenic distillation column (100) for isotope separation according to claim 1, wherein, The volume (27) between the insulating container element (22) and the internal column element (23) operates under vacuum, wherein the internal column element (23) is enclosed by the at least one insulating container element (22…22n); or the volume (27) is filled with a special insulating material suitable for operation as a cryogenic distillation column, thereby minimizing heat transfer and minimizing the effect of temperature changes of the internal column element (23…23n) on the at least one insulating container element (22…22n).

8. The cryogenic distillation column (100) for isotope separation according to claim 7, wherein, The volume (27) includes service pipelines, wherein the service pipelines include corrugated pipes for compensating for thermal expansion or contraction of the service pipelines.

9. The cryogenic distillation column (100) for isotope separation according to claim 1, wherein, The cryogenic distillation column (100) includes an economical heat exchanger for reducing the cost of the isotope separation process by recovering the enthalpy consumed and gained at the reboiler and condenser.

10. A method for assembling a cryogenic distillation column for isotope separation, the method comprising: Position at least one reboiler at the bottom end of the low-temperature distillation column (100); Multiple central modular elements (5…5n) are connected in series, wherein the multiple central modular elements (5…5n) include: At least one insulating container element (22…22n), and At least one internal column element (23…23n). One or more of the multiple bellows are connected to each insulated container element (22) and each internal column element (23…23n) respectively to compensate for the thermal expansion or contraction of the column; The at least one internal column element (23…23n) is encapsulated within the insulating container element (22…22n) to provide thermal insulation for the internal column element (23…23n) while ensuring that the end portions of two adjacent internal column elements (23) are not enclosed by the at least one insulating container element (22…22n). The end portions of the two adjacent internal column elements (23…23n) that are not enclosed by the at least one insulating container element (22…22n) are connected to each other by a first weld. The welded end portions of the two adjacent inner column elements (23…23n) are wrapped by the at least one insulating container element (22…22n); After the welded end portion is wrapped by at least one insulating container element (22…22n), the outer sleeve is lifted toward the ends of the outer diameters of the two adjacent insulating container elements (22…22n); After the outer sleeve is lifted, the outer sleeve is positioned around the ends of the outer diameters of the two adjacent insulating container elements (22n) to cover and perform a second weld (34) on the ends of the outer diameters of the two adjacent insulating container elements (22n), thereby closing the ends; Wherein, when one or more central modular elements (5…5n) of the cryogenic distillation column (100) expand due to temperature rise, the height change of the cryogenic distillation column (100) is compensated by the contraction of the bellows (25, 26) contained in each central modular element (5…5n) of the cryogenic distillation column (100), and when one or more central modular elements (5…5n) of the cryogenic distillation column (100) contract due to temperature decrease, the height change of the cryogenic distillation column (100) is compensated by the expansion of the bellows (25, 26), thereby allowing the construction of cryogenic distillation columns (100) of predetermined height, even exceeding 100 meters, and ensuring that the final height of the cryogenic distillation column (100) connected to the top and bottom supports of the supporting structure always remains the same as the predetermined height.

11. The assembly method of the cryogenic distillation column (100) for isotope separation according to claim 10, wherein, The connection between the at least one external isolation container element (22) and the at least one internal column element (23) is a free connection, achieved through a sliding joint, a sliding support, and a chain link, so as to allow the internal column element to adjust its position relative to the external isolation container element in the axial direction, thereby enabling it to slide freely in the axial direction to locally compensate for the thermal expansion or contraction of any of its components within the height range of the module element (5).

12. The assembly method of the cryogenic distillation column (100) for isotope separation according to claim 10, wherein, The connection between the at least one external isolation container element (22) and the at least one internal column element (23) is a fixed connection at one or more points.

13. The method of assembling a cryogenic distillation column (100) for isotope separation according to claim 10, further comprising a volume (27) between an isolation container element (22) and an internal column element (23), the volume including a service line connected to a bellows to compensate for thermal expansion or contraction of the service line.

14. The method for assembling the cryogenic distillation column (100) for isotope separation according to claim 10, further comprising: Multiple bellows mounting positions are provided within a portion of each insulating container element (22) and a portion of each internal column element (23…23n), and one or more of the multiple bellows (25, 26) are adapted to the bellows mounting positions to compensate for the thermal expansion or contraction of the column.

15. The method for assembling the cryogenic distillation column (100) for isotope separation according to claim 10, further comprising: Each central module element (5…5n) is connected to at least one structural support (28), which is connected to a platform (29) fixed to at least one structural plate (30). After each central module element (5…5n) is connected to at least one structural support (28), platform (29) and at least one structural plate (30), the at least one structural plate (30) is fixed to the well wall or mine wall directly or by other structural elements by rock bolts (31).

16. The method for assembling the cryogenic distillation column (100) for isotope separation according to claim 10, further comprising: After connecting each central module element (5…5n) to at least one structural support (28), platform (29) and at least one structural plate (30), a condenser is placed on top of the column to construct a cryogenic distillation column (100) with a predetermined height, or even higher than 100 meters.

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