CA2346842C - Storage installation for liquified gases - Google Patents
Storage installation for liquified gases Download PDFInfo
- Publication number
- CA2346842C CA2346842C CA002346842A CA2346842A CA2346842C CA 2346842 C CA2346842 C CA 2346842C CA 002346842 A CA002346842 A CA 002346842A CA 2346842 A CA2346842 A CA 2346842A CA 2346842 C CA2346842 C CA 2346842C
- Authority
- CA
- Canada
- Prior art keywords
- mass
- tank
- installation
- installation according
- shell
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C3/00—Vessels not under pressure
- F17C3/005—Underground or underwater containers or vessels
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C3/00—Vessels not under pressure
- F17C3/02—Vessels not under pressure with provision for thermal insulation
- F17C3/022—Land-based bulk storage containers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C3/00—Vessels not under pressure
- F17C3/02—Vessels not under pressure with provision for thermal insulation
- F17C3/04—Vessels not under pressure with provision for thermal insulation by insulating layers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2201/00—Vessel construction, in particular geometry, arrangement or size
- F17C2201/01—Shape
- F17C2201/0104—Shape cylindrical
- F17C2201/0109—Shape cylindrical with exteriorly curved end-piece
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2201/00—Vessel construction, in particular geometry, arrangement or size
- F17C2201/01—Shape
- F17C2201/0104—Shape cylindrical
- F17C2201/0119—Shape cylindrical with flat end-piece
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2201/00—Vessel construction, in particular geometry, arrangement or size
- F17C2201/05—Size
- F17C2201/052—Size large (>1000 m3)
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2203/00—Vessel construction, in particular walls or details thereof
- F17C2203/03—Thermal insulations
- F17C2203/0304—Thermal insulations by solid means
- F17C2203/0337—Granular
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2203/00—Vessel construction, in particular walls or details thereof
- F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
- F17C2203/0634—Materials for walls or layers thereof
- F17C2203/0636—Metals
- F17C2203/0639—Steels
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2203/00—Vessel construction, in particular walls or details thereof
- F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
- F17C2203/0634—Materials for walls or layers thereof
- F17C2203/0678—Concrete
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2221/00—Handled fluid, in particular type of fluid
- F17C2221/03—Mixtures
- F17C2221/032—Hydrocarbons
- F17C2221/033—Methane, e.g. natural gas, CNG, LNG, GNL, GNC, PLNG
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
- F17C2223/01—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the phase
- F17C2223/0146—Two-phase
- F17C2223/0153—Liquefied gas, e.g. LPG, GPL
- F17C2223/0161—Liquefied gas, e.g. LPG, GPL cryogenic, e.g. LNG, GNL, PLNG
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
- F17C2223/03—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the pressure level
- F17C2223/033—Small pressure, e.g. for liquefied gas
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2227/00—Transfer of fluids, i.e. method or means for transferring the fluid; Heat exchange with the fluid
- F17C2227/03—Heat exchange with the fluid
- F17C2227/0302—Heat exchange with the fluid by heating
- F17C2227/0304—Heat exchange with the fluid by heating using an electric heater
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2227/00—Transfer of fluids, i.e. method or means for transferring the fluid; Heat exchange with the fluid
- F17C2227/03—Heat exchange with the fluid
- F17C2227/0367—Localisation of heat exchange
- F17C2227/0388—Localisation of heat exchange separate
- F17C2227/039—Localisation of heat exchange separate on the pipes
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
- F17C2250/04—Indicating or measuring of parameters as input values
- F17C2250/0404—Parameters indicated or measured
- F17C2250/0439—Temperature
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2260/00—Purposes of gas storage and gas handling
- F17C2260/01—Improving mechanical properties or manufacturing
- F17C2260/011—Improving strength
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2270/00—Applications
- F17C2270/01—Applications for fluid transport or storage
- F17C2270/0134—Applications for fluid transport or storage placed above the ground
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2270/00—Applications
- F17C2270/01—Applications for fluid transport or storage
- F17C2270/0142—Applications for fluid transport or storage placed underground
- F17C2270/0144—Type of cavity
- F17C2270/0147—Type of cavity by burying vessels
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Filling Or Discharging Of Gas Storage Vessels (AREA)
Abstract
An installation for storing liquefied gas in a cavity defined by rock or an outer shell (10) made of concrete, comprising a tank (2) for the gas. The tank (2) which is made of concrete and possibly thermally insulated, is entirely or partly surrounded by a mass (5) filling a void between the tank (2) and the rock or the concrete shell (10). The mass (5) may in itself be sealing, i.e. of low permeability, and may be combined with at least one sealing membrane (13) within the mass (5), or outside or inside the mass. The installation may be located entirely or partly in loose soil (8) which entirely or partly surrounds the shell (10), or be located above ground level.
Description
Storage installation for lipuified gases The present invention relates to a storage installation for liquified gases, such as LNG, i.e. gases which at temperatures below 0°C boil at atmospheric pressure s and which can be liquifled by further cooling.
Such gases may be stored in excavated rock cavities and which constitute a so-called ground depot. The alternative to such ground depots is tanks laid into the ground, entirely above the ground level, or tanks partly above and partly below the 1o ground level. If the facility is positioned entirely or partly below ground level, the storage may be above, at or below the ground- water level. The pressure above the liquified gas may be about 1 bar abs., normally slightly higher, such as 1,1 bar abs.. In the liquified gas the pressure, of course, increases downwards from the surface of the liquid but the pressure would be lower than in the possibly 1s surrounding ground-water. The low temperature of the gas can be maintained by feeding the gas (gaseous phase) above the surface of the liquid to a refrigerator to be recondenced to a liquid which is fed back into the tanks, according to conventional techniques.
2o In rock cavities for this kind of storage it has been attempted to use a concrete lining against the rock. The store has been insulated by adhering insulation onto the concrete lining, or in some cases, directly onto the rock without the use of steel lining. Experiments have shown that due to dissimilar contraction during the cooling, adherence problems arise between the different materials, the result of 2s which being a great risk for the insulation to fall down. Also, if it is not sealed off by means of a membrane of special steel, such a storage facility is prone to leakage, resulting in excessive expenses.
Tanks of steel or tanks of concrete lined with steel have been employed as tanks so on or below the ground. Due to the lower temperature level highly costly special steel must be used, as steel of a more normal type becomes brittle at low temperatures. The cost for producing such installations is a serious disadvantage.
Such gases may be stored in excavated rock cavities and which constitute a so-called ground depot. The alternative to such ground depots is tanks laid into the ground, entirely above the ground level, or tanks partly above and partly below the 1o ground level. If the facility is positioned entirely or partly below ground level, the storage may be above, at or below the ground- water level. The pressure above the liquified gas may be about 1 bar abs., normally slightly higher, such as 1,1 bar abs.. In the liquified gas the pressure, of course, increases downwards from the surface of the liquid but the pressure would be lower than in the possibly 1s surrounding ground-water. The low temperature of the gas can be maintained by feeding the gas (gaseous phase) above the surface of the liquid to a refrigerator to be recondenced to a liquid which is fed back into the tanks, according to conventional techniques.
2o In rock cavities for this kind of storage it has been attempted to use a concrete lining against the rock. The store has been insulated by adhering insulation onto the concrete lining, or in some cases, directly onto the rock without the use of steel lining. Experiments have shown that due to dissimilar contraction during the cooling, adherence problems arise between the different materials, the result of 2s which being a great risk for the insulation to fall down. Also, if it is not sealed off by means of a membrane of special steel, such a storage facility is prone to leakage, resulting in excessive expenses.
Tanks of steel or tanks of concrete lined with steel have been employed as tanks so on or below the ground. Due to the lower temperature level highly costly special steel must be used, as steel of a more normal type becomes brittle at low temperatures. The cost for producing such installations is a serious disadvantage.
Through the present invention an installation has been arrived at which solves the above problems and which also is considerably cheaper than prior art facilities for storing liquified gases at temperatures below about -45°C (in tanks of steel).
The installation according to the present invention for storing gases in a cavity defined by rock or an outer concrete shell comprises a tank for the gas, the tank being made of concrete and possibly thermally insulated, the installation being characterized in that the tank is entirely or partly surrounded by a mass filling a space between the tank and the rock or the concrete shell, the mass itself being 1o thermally insulating and capable of causing sealing.
The sealing is performed by the mass filling the space or void, either by means of the mass as such or by means of one or more membranes which may be placed within the mass, or on the outer or inner face thereof.
The invention makes it possible to make such an installation either in an excavated rock cavity , or in loose soil, partly within the loose soil and partly above ground level, or entirely above ground level. Here, the expression loose soil refers to any substance that is not a solid matter, such as earth, sand, 2o shingle, gravel, or a mixture thereof. The loose soil may be arranged around the installation, or a depression may be formed in the loose soil in which the installation is placed. Where an outer shell encapsules the tank, the shell absorbs the pressure from within the mass filling the space such that the installation is independent from the surrounding medium which, as indicated, may be loose soil, partly loose soil and partly. atmospheric air, or atmospheric air exclusively.
When it is to possess sealing capabilities, the mass filling the space may be clay, for example, possibly added a thermally insulating material. An exemplary additive is loose Leca. The addition of such a material may eventually lead to the so avoidance of arranging separate thermal insulation on and/or in the tank, or that such insulation may be substantially reduced. When being cooled from 0°C to a certain temperature, clay has the capability of expanding, and hence it will maintain a tight engagement with the rock or the shell, and with the concrete tank.
However, to avoid overloading the tank andlor the shell by pressure caused by the expansion of the clay, a "crushable material" may be arranged as a shim between the clay and the tank, or between the clay and the shell, such that this "crushable material" crumbles at a certain pressure and prevents the transfer of a to high pressure onto the tank andlor shell. If insulation is placed between the s mass and concrete this insulation may act as "crushable material".
The mass filling the space may be a natural or a factory-made product. As the mass itself shall be sealing, its permeability should be extremely small such that the mass acts like a membrane sealing off the installation. An exemplary natural ~o product is clay with a large contents of fine particles. Exemplary factory-made products are clay in the form of powder or pellets (bentonite) to which water, finely grounded limestone, slag from industrial processes, flight ashes (e.g.
vulcanic), silica dust, etc., may be added. Although it is not mandatory, it is an advantage for the mass to be thermally insulating. Insulation may be arranged in layers ~s inside or outside the tank. Although it is not mandatory, it is also advantageous for the mass to be expanding at temperatures below 0°C.
After the starting-up of the installation and when a stable temperature is present (in reality, the temperature falls as long as the installation is in operation), heat 2o may be supplied to the mass. If the mass is clay or a similar material which becomes brittle and tends to break up at lower temperatures, heat may be supplied such that the mass or portions thereof be kept at a temperature across the entire or portions of the thickness being higher than the temperature at which the mass transforms from being plastic to being brittle. Similarly, if the mass 2s contains one or more membranes, heat may be supplied to avoid cooling down of the membrane or membranes to a temperature where it/they becomeslbecome brittle or is/are likely to break. The supply of heat makes the choice of material for the membrane or membranes less critical. For example, steel of a normal grade, i.e. not an expensive special steel, may be used.
When the storage facility has been put in operation by being filled with liquified gas, slow cooling of the tank, possible insulation, the mass in the space as well as the rock or shell around the cold gas takes place and the zero-isotherm is constantly moved outwards from the storage. In this connection it should be noted that insulation may be favourable also in respect of the time that elapses for the starting-up. To prepare the installation for storage liquified gas is supplied, which due to the heat supply from the surroundings (the concrete tank, the possible insulation, the surrounding mass and rock or shell) will evaporate.
s Evaporated gas is removed, and condensed gas that is supplied evaporates such that the temperature of the surroundings constantly becomes lower. The time it takes to bring the surroundings down to such a temperature where the evaporation is minimal and the installation may be regarded as being in stable operation is substantially shortened by thermal insulation in addition to the mass.
~o A shortening of the starting-up period is of great economic value due to the very large sums of money invested in such facilities.
The insulation material also provides the effect that the mass and rock or shell are not subjected to such a low temperature as when insulation is not used. Thus, 15 problems regarding sealing of the storage can be avoided.
The mass between the tank and rock or shell may be of such a kind that it does not contract nor break up at the temperatures occuring in this regions. In order to prevent the temperature from being so low that the mass transforms from a 2o viscous to a brittle behavior with subsequent cracking, or that the membrane or membranes becomes/become brittle, heating means, such as tubes, hoses, heating elements, combined with temperature sensors, may be mounted, such that heating can be effected to prevent the temperature from being so low that cracking of the mass occurs, or the membrane or membranes becomes/become 2s brittle. Such heating means are first put in service when the installation is approaching its approximate stable operation state, as heating during the starting-up would prolong the time for starting-up.
Such an installation exhibits a high grade of safety. Due to the mass and possible so ground-water surrounding the tank cracks in the concrete tank, in the possible insulation and/or in the shell will not cause any outward leakage of product or inward ground-water leakage, either by the fact that the mass does not crack, or that the membrane. or membranes performs/perform a sealing function.
Compared with the use of steel tanks it is, in addition to the economic savings, achieved the certainty that cracks which may arise in the concrete tank do not have any consequences regarding leakage of the product in liquid or gaseous form, since the surrounding mass, or the mass combined with one or more s membranes, and possibly the ground-water, will seal against further outbound leakage.
The thermal insulation of the concrete tank may be external andlor internal.
In any case, an insulation material must be used which the product does not ~o penetrate into and which does not react with the product, since cracks in the concrete tank will occur.
In the following an installation according to the invention will be described by way of examples schematically illustrated on the enclosed drawings, on which Figs.
to 5 show an installation having a tank located in a cavity excavated in rock, while Figs. 6 to 9 show an outer shell around a tank.
Fig. 1 shows a horizontal section through an embodiment of an installation according to the invention.
2o Fig. 2 shows a vertical section through an installation according to the invention.
Fig. 3 shows a vertical section through a somewhat different embodiment of an installation according to the invention.
Fig. 4 shows a horizontal section through an installation according to the invention, with one membrane located in the mass surrounding the 2s concrete tank.
Fig. 5 shows a vertical section through the installation of Fig. 4.
Fig. 6 shows a horizontal section through another embodiment of an installation according to the invention.
Fig. 7 shows a vertical section through the installation of Fig. 6.
so Fig. 8 shows a horizontal section through an installation according to the invention, with a membrane located in the mass surrounding the concrete tank.
Fig. 9 shows a vertical section through the installation of Fig. 8.
Figure 1 may be regarded as a section through each of the insulated tanks shown in Figs. 2 and 3.
Fig. 1 shows a concrete tank 2 having a circular cross-section. A layer of thermal s insulation 3 is arranged outside the tank 2, and the unit comprising a tank 2 and the insulation is surrounded by a mass 5 which also bears against the surrounding rock 6. In its inner chamber 1 the tank 2 contains liqui~ed gas. Between the insulation 3 and mass 5 "crushable material" 4 is inserted, this material being intended to crack if the outer pressure against the tank 2 exceeds a certain value, ~o thus preventing the tank 2 to be overloaded because of swelling of the mass when cooled. Apparently the rock wall generally will not be of a regular shape, such as that shown, but rather be irregular.
Figs. 2 and 3 show vertical cross-sections through two alternative embodiments ~s which have in common that the cylindrical portion of the tank 2, the insulation 3, the "crushable material" 4 and the mass 5 may be disposed as shown in figure 1.
Also, the roof 7 is similarly constructed as the cylindrical portion, except that the roof 7 is shown as being dome-shaped. "Crushable elements" 4 are inserted in the roof 7, too. Contrary to the embodiment of Fig. 2, the embodiment of Fig.
2o comprises crushable material underneath the concrete tank.
The embodiment of Fig. 2 comprises a concrete sole 8 having branches 9 (ribs, posts) down to the rock, and in between these branches there are voids containing insulation and mass, correspondingly as the wall and roof of the tank.
2s The sole 8 and branches.9 support the rest of the tank 2.
The embodiment of Fig. 3 comprises, on the other hand, a bottom 10 constructed with insulation as the rest of the tank, while a mass 5 corresponding to that surrounding the tank and covering the roof 7 forms the foundation for the tank.
so Thus, the tank 2 and the insulation 3 are completely surrounded by the mass which also supports the tank. The bottom of the tank 2 and the insulation 3 beneath the bottom are dome-shaped, correspondingly as the roof 7. It is well known that dome-shaped end portions are far more capable of withstanding loading from outside than planar end portions, for example.
The embodiment of Figs. 4 and 5 is similar to the embodiment of Figs. 1 and 3 by comprising the same elements but differ therefrom by the fact that the mass 5 contains a sealing membrane 11. It should be understood that the membrane may be located inside or outside the mass and that one or more membranes 11 s may be employed. In this case, the mass 5 may be a liquid permeable material, such as sand.
Fig. 6 illustrates a concrete tank 2 having a circular cross-section. A Layer of thermal insulation 3 is arranged outside the tank 2, and the unit comprising the ~o tank 2 and the insulation is surrounded by a mass 5 which also bears against a surrounding shell 10 made of concrete. In its inner chamber 1 the tank 2 contains liquified gas. A "crushable material" 4 is inserted between the insulation 3 and mass 5, being intended to crack if the outer pressure against the tank 2 exceeds a certain value, thus preventing overloading of the tank 2 and/or shell 10 due to ~s the swelling of the mass 5 when cooled. The Fig. illustrates an installation surrounded by loose soil 8. The loose soil may be arranged around the installation, or a depression may be excavated in loose soil in which the installation is entirely or partly disposed.
2o Fig. 7 is a vertical cross-sectional view through the installation shown in Fig. 6.
Besides the elements that appear from Fig. 6, Fig. 7 shows a dome-shaped bottom 6 and a dome-shaped top 7 of the tank 2, a roof covering 12 made of metal or some other weather proof material, a shell bottom 9 and an upper shell collar 11. It is well known that dome-shaped end portions are far more capable of 2s withstanding loading from outside than planar end portions, for example.
Thus, the installation is located in a depression in the loose soil 8, or the loose soil 8 is arranged around the installation, such that only the top 7 and the roof covering 12 extend above the loose soil 8.
Even underneath the bottom 6 "crushable elements" 4 are inserted.
The embodiment of Figs. 8 and 9 is similar to the embodiment of Figs. 6 and 7 by comprising the same elements, but differ therefrom by the fact that the mass 5 contains a sealing membrane 13. It should be understood that the membrane may be located outside or inside the mass 5 and that one or more membranes 13 may be employed. In this case, the mass 5 may be a liquid permeable material, such as sand.
s The embodiments shown should be regarded as being schematic. A sump or recession for a loading pump and tubings is not shown, nor is a possible heating means illustrated.
~o Several modifications are possible relatively to the examples shown. For example, insulation may also be mounted internally in the tank 2. It is also envisaged to add to the mass 5 sufficient insulating material, such as Leca, such that the insulation on or in the tank 2 can be omitted, except that the top 7 should be insulated if it is not covered by the mass 5.
The installation according to the present invention for storing gases in a cavity defined by rock or an outer concrete shell comprises a tank for the gas, the tank being made of concrete and possibly thermally insulated, the installation being characterized in that the tank is entirely or partly surrounded by a mass filling a space between the tank and the rock or the concrete shell, the mass itself being 1o thermally insulating and capable of causing sealing.
The sealing is performed by the mass filling the space or void, either by means of the mass as such or by means of one or more membranes which may be placed within the mass, or on the outer or inner face thereof.
The invention makes it possible to make such an installation either in an excavated rock cavity , or in loose soil, partly within the loose soil and partly above ground level, or entirely above ground level. Here, the expression loose soil refers to any substance that is not a solid matter, such as earth, sand, 2o shingle, gravel, or a mixture thereof. The loose soil may be arranged around the installation, or a depression may be formed in the loose soil in which the installation is placed. Where an outer shell encapsules the tank, the shell absorbs the pressure from within the mass filling the space such that the installation is independent from the surrounding medium which, as indicated, may be loose soil, partly loose soil and partly. atmospheric air, or atmospheric air exclusively.
When it is to possess sealing capabilities, the mass filling the space may be clay, for example, possibly added a thermally insulating material. An exemplary additive is loose Leca. The addition of such a material may eventually lead to the so avoidance of arranging separate thermal insulation on and/or in the tank, or that such insulation may be substantially reduced. When being cooled from 0°C to a certain temperature, clay has the capability of expanding, and hence it will maintain a tight engagement with the rock or the shell, and with the concrete tank.
However, to avoid overloading the tank andlor the shell by pressure caused by the expansion of the clay, a "crushable material" may be arranged as a shim between the clay and the tank, or between the clay and the shell, such that this "crushable material" crumbles at a certain pressure and prevents the transfer of a to high pressure onto the tank andlor shell. If insulation is placed between the s mass and concrete this insulation may act as "crushable material".
The mass filling the space may be a natural or a factory-made product. As the mass itself shall be sealing, its permeability should be extremely small such that the mass acts like a membrane sealing off the installation. An exemplary natural ~o product is clay with a large contents of fine particles. Exemplary factory-made products are clay in the form of powder or pellets (bentonite) to which water, finely grounded limestone, slag from industrial processes, flight ashes (e.g.
vulcanic), silica dust, etc., may be added. Although it is not mandatory, it is an advantage for the mass to be thermally insulating. Insulation may be arranged in layers ~s inside or outside the tank. Although it is not mandatory, it is also advantageous for the mass to be expanding at temperatures below 0°C.
After the starting-up of the installation and when a stable temperature is present (in reality, the temperature falls as long as the installation is in operation), heat 2o may be supplied to the mass. If the mass is clay or a similar material which becomes brittle and tends to break up at lower temperatures, heat may be supplied such that the mass or portions thereof be kept at a temperature across the entire or portions of the thickness being higher than the temperature at which the mass transforms from being plastic to being brittle. Similarly, if the mass 2s contains one or more membranes, heat may be supplied to avoid cooling down of the membrane or membranes to a temperature where it/they becomeslbecome brittle or is/are likely to break. The supply of heat makes the choice of material for the membrane or membranes less critical. For example, steel of a normal grade, i.e. not an expensive special steel, may be used.
When the storage facility has been put in operation by being filled with liquified gas, slow cooling of the tank, possible insulation, the mass in the space as well as the rock or shell around the cold gas takes place and the zero-isotherm is constantly moved outwards from the storage. In this connection it should be noted that insulation may be favourable also in respect of the time that elapses for the starting-up. To prepare the installation for storage liquified gas is supplied, which due to the heat supply from the surroundings (the concrete tank, the possible insulation, the surrounding mass and rock or shell) will evaporate.
s Evaporated gas is removed, and condensed gas that is supplied evaporates such that the temperature of the surroundings constantly becomes lower. The time it takes to bring the surroundings down to such a temperature where the evaporation is minimal and the installation may be regarded as being in stable operation is substantially shortened by thermal insulation in addition to the mass.
~o A shortening of the starting-up period is of great economic value due to the very large sums of money invested in such facilities.
The insulation material also provides the effect that the mass and rock or shell are not subjected to such a low temperature as when insulation is not used. Thus, 15 problems regarding sealing of the storage can be avoided.
The mass between the tank and rock or shell may be of such a kind that it does not contract nor break up at the temperatures occuring in this regions. In order to prevent the temperature from being so low that the mass transforms from a 2o viscous to a brittle behavior with subsequent cracking, or that the membrane or membranes becomes/become brittle, heating means, such as tubes, hoses, heating elements, combined with temperature sensors, may be mounted, such that heating can be effected to prevent the temperature from being so low that cracking of the mass occurs, or the membrane or membranes becomes/become 2s brittle. Such heating means are first put in service when the installation is approaching its approximate stable operation state, as heating during the starting-up would prolong the time for starting-up.
Such an installation exhibits a high grade of safety. Due to the mass and possible so ground-water surrounding the tank cracks in the concrete tank, in the possible insulation and/or in the shell will not cause any outward leakage of product or inward ground-water leakage, either by the fact that the mass does not crack, or that the membrane. or membranes performs/perform a sealing function.
Compared with the use of steel tanks it is, in addition to the economic savings, achieved the certainty that cracks which may arise in the concrete tank do not have any consequences regarding leakage of the product in liquid or gaseous form, since the surrounding mass, or the mass combined with one or more s membranes, and possibly the ground-water, will seal against further outbound leakage.
The thermal insulation of the concrete tank may be external andlor internal.
In any case, an insulation material must be used which the product does not ~o penetrate into and which does not react with the product, since cracks in the concrete tank will occur.
In the following an installation according to the invention will be described by way of examples schematically illustrated on the enclosed drawings, on which Figs.
to 5 show an installation having a tank located in a cavity excavated in rock, while Figs. 6 to 9 show an outer shell around a tank.
Fig. 1 shows a horizontal section through an embodiment of an installation according to the invention.
2o Fig. 2 shows a vertical section through an installation according to the invention.
Fig. 3 shows a vertical section through a somewhat different embodiment of an installation according to the invention.
Fig. 4 shows a horizontal section through an installation according to the invention, with one membrane located in the mass surrounding the 2s concrete tank.
Fig. 5 shows a vertical section through the installation of Fig. 4.
Fig. 6 shows a horizontal section through another embodiment of an installation according to the invention.
Fig. 7 shows a vertical section through the installation of Fig. 6.
so Fig. 8 shows a horizontal section through an installation according to the invention, with a membrane located in the mass surrounding the concrete tank.
Fig. 9 shows a vertical section through the installation of Fig. 8.
Figure 1 may be regarded as a section through each of the insulated tanks shown in Figs. 2 and 3.
Fig. 1 shows a concrete tank 2 having a circular cross-section. A layer of thermal s insulation 3 is arranged outside the tank 2, and the unit comprising a tank 2 and the insulation is surrounded by a mass 5 which also bears against the surrounding rock 6. In its inner chamber 1 the tank 2 contains liqui~ed gas. Between the insulation 3 and mass 5 "crushable material" 4 is inserted, this material being intended to crack if the outer pressure against the tank 2 exceeds a certain value, ~o thus preventing the tank 2 to be overloaded because of swelling of the mass when cooled. Apparently the rock wall generally will not be of a regular shape, such as that shown, but rather be irregular.
Figs. 2 and 3 show vertical cross-sections through two alternative embodiments ~s which have in common that the cylindrical portion of the tank 2, the insulation 3, the "crushable material" 4 and the mass 5 may be disposed as shown in figure 1.
Also, the roof 7 is similarly constructed as the cylindrical portion, except that the roof 7 is shown as being dome-shaped. "Crushable elements" 4 are inserted in the roof 7, too. Contrary to the embodiment of Fig. 2, the embodiment of Fig.
2o comprises crushable material underneath the concrete tank.
The embodiment of Fig. 2 comprises a concrete sole 8 having branches 9 (ribs, posts) down to the rock, and in between these branches there are voids containing insulation and mass, correspondingly as the wall and roof of the tank.
2s The sole 8 and branches.9 support the rest of the tank 2.
The embodiment of Fig. 3 comprises, on the other hand, a bottom 10 constructed with insulation as the rest of the tank, while a mass 5 corresponding to that surrounding the tank and covering the roof 7 forms the foundation for the tank.
so Thus, the tank 2 and the insulation 3 are completely surrounded by the mass which also supports the tank. The bottom of the tank 2 and the insulation 3 beneath the bottom are dome-shaped, correspondingly as the roof 7. It is well known that dome-shaped end portions are far more capable of withstanding loading from outside than planar end portions, for example.
The embodiment of Figs. 4 and 5 is similar to the embodiment of Figs. 1 and 3 by comprising the same elements but differ therefrom by the fact that the mass 5 contains a sealing membrane 11. It should be understood that the membrane may be located inside or outside the mass and that one or more membranes 11 s may be employed. In this case, the mass 5 may be a liquid permeable material, such as sand.
Fig. 6 illustrates a concrete tank 2 having a circular cross-section. A Layer of thermal insulation 3 is arranged outside the tank 2, and the unit comprising the ~o tank 2 and the insulation is surrounded by a mass 5 which also bears against a surrounding shell 10 made of concrete. In its inner chamber 1 the tank 2 contains liquified gas. A "crushable material" 4 is inserted between the insulation 3 and mass 5, being intended to crack if the outer pressure against the tank 2 exceeds a certain value, thus preventing overloading of the tank 2 and/or shell 10 due to ~s the swelling of the mass 5 when cooled. The Fig. illustrates an installation surrounded by loose soil 8. The loose soil may be arranged around the installation, or a depression may be excavated in loose soil in which the installation is entirely or partly disposed.
2o Fig. 7 is a vertical cross-sectional view through the installation shown in Fig. 6.
Besides the elements that appear from Fig. 6, Fig. 7 shows a dome-shaped bottom 6 and a dome-shaped top 7 of the tank 2, a roof covering 12 made of metal or some other weather proof material, a shell bottom 9 and an upper shell collar 11. It is well known that dome-shaped end portions are far more capable of 2s withstanding loading from outside than planar end portions, for example.
Thus, the installation is located in a depression in the loose soil 8, or the loose soil 8 is arranged around the installation, such that only the top 7 and the roof covering 12 extend above the loose soil 8.
Even underneath the bottom 6 "crushable elements" 4 are inserted.
The embodiment of Figs. 8 and 9 is similar to the embodiment of Figs. 6 and 7 by comprising the same elements, but differ therefrom by the fact that the mass 5 contains a sealing membrane 13. It should be understood that the membrane may be located outside or inside the mass 5 and that one or more membranes 13 may be employed. In this case, the mass 5 may be a liquid permeable material, such as sand.
s The embodiments shown should be regarded as being schematic. A sump or recession for a loading pump and tubings is not shown, nor is a possible heating means illustrated.
~o Several modifications are possible relatively to the examples shown. For example, insulation may also be mounted internally in the tank 2. It is also envisaged to add to the mass 5 sufficient insulating material, such as Leca, such that the insulation on or in the tank 2 can be omitted, except that the top 7 should be insulated if it is not covered by the mass 5.
Claims (9)
1. ~Installation for storing liquified gas in a cavity defined by rock or an outer concrete shell, comprising a tank for the gas, the tank being made of concrete and being thermally insulating, characterized in that the tank is entirely or partly surrounded by a mass filling a void between the tank and the rock or the outer shell, the mass itself causing sealing and being thermally insulating.
2. ~An installation according to claim 1, characterized in that the mass is natural clay.
3. ~An installation according to claim 1, characterized in that the mass is clay made of powder or pellets to which water is added.
4. ~An installation according to claim 1, characterized in that the mass is a factory-made material.
5. ~An installation according to any one of the claims 1 to 4, characterized in that the mass contains an additive of a thermally insulating material.
6. ~An installation according to claim 1, characterized in that the installation is located entirely or partly in loose soil which entirely or partly surrounds the shell.
7. ~An installation according to claim 1, characterized in that the installation is located above the ground level.
8. ~An installation according to any one of claims 1 to 7, characterized in that the mass contains one or more membranes.
9. ~An installation according to any one of claims 1 to 8, characterized in that the mass is surrounded by one or more membranes.
An installation according to claim 4, characterized in that the mass is a finely grounded limestone or slag.
An installation according to claim 4, characterized in that the mass is a finely grounded limestone or slag.
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NO984763A NO308624B1 (en) | 1998-10-12 | 1998-10-12 | Plants for storing liquefied gas in a basic reservoir in an exploded mountain room |
NO19985502 | 1998-11-25 | ||
NO19984763 | 1998-11-25 | ||
NO19985502A NO310319B1 (en) | 1998-10-12 | 1998-11-25 | Liquefied gas storage facility |
PCT/NO1999/000307 WO2000025059A1 (en) | 1998-10-12 | 1999-10-08 | Storage installation for liquified gases |
Publications (2)
Publication Number | Publication Date |
---|---|
CA2346842A1 CA2346842A1 (en) | 2000-05-04 |
CA2346842C true CA2346842C (en) | 2007-02-06 |
Family
ID=26648903
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA002346842A Expired - Fee Related CA2346842C (en) | 1998-10-12 | 1999-10-08 | Storage installation for liquified gases |
Country Status (11)
Country | Link |
---|---|
EP (1) | EP1125084A1 (en) |
JP (1) | JP2002528691A (en) |
KR (1) | KR20010090789A (en) |
CN (1) | CN1105258C (en) |
AU (1) | AU764312B2 (en) |
BR (1) | BR9914406A (en) |
CA (1) | CA2346842C (en) |
ID (1) | ID29941A (en) |
NO (1) | NO310319B1 (en) |
RU (1) | RU2244204C2 (en) |
WO (1) | WO2000025059A1 (en) |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100709901B1 (en) * | 2005-07-12 | 2007-04-24 | 에스케이건설 주식회사 | Evaluation criteria and its design application on thermo-mechanical stability in rock mass around lined rock cavern for underground LNG or any other cryogenic liquid gas storage |
WO2011055652A1 (en) * | 2009-11-06 | 2011-05-12 | 本田技研工業株式会社 | Gas tank |
CN102011505A (en) * | 2010-10-25 | 2011-04-13 | 潞城市新蓝天生物质能源开发有限公司 | Storage tank used for oil station and gas station |
RU2510360C2 (en) * | 2012-04-02 | 2014-03-27 | Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Санкт-Петербургский государственный горный университет" | Underground liquefied natural gas storage |
FR2994245B1 (en) * | 2012-08-03 | 2015-05-29 | Gaztransp Et Technigaz | SEALED AND THERMALLY INSULATING TANK WALL WITH SPACER CARRIER ELEMENTS |
FR3008163B1 (en) * | 2013-07-02 | 2015-11-13 | Gaztransp Et Technigaz | CALORIFUGE ELEMENT SUITABLE FOR THE PRODUCTION OF AN INSULATING BARRIER IN A WATERPROOF AND INSULATING TANK |
RU2572257C2 (en) * | 2013-12-30 | 2016-01-10 | Евгений Михайлович Попов | Modular system for working and storing of hydrocarbons |
RU2667708C1 (en) * | 2017-09-01 | 2018-09-24 | Александр Юрьевич Климентьев | Helium storage |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1136201A (en) * | 1967-05-06 | 1968-12-11 | Cryogenic Entpr Ltd | Improvements relating to cryogenic liquid storage containers |
US3848418A (en) * | 1972-04-24 | 1974-11-19 | Osaka Gas Co Ltd | Underground storage tank for low temperature liquefied gas |
JPS594600B2 (en) * | 1976-07-02 | 1984-01-30 | 三井液化ガス株式会社 | Low temperature liquefied gas tank |
NL7711018A (en) * | 1977-10-07 | 1979-04-10 | Shell Int Research | TANK FOR LIQUEFIED GAS. |
US4344264A (en) * | 1980-06-09 | 1982-08-17 | Mcdonnell Douglas Corporation | Flexible corner seal structure for cryogenic container |
JPS6088297A (en) * | 1983-10-18 | 1985-05-18 | Taisei Corp | Storage tank for low temperature fluid |
JPH0610519B2 (en) * | 1985-12-05 | 1994-02-09 | 大成建設株式会社 | Triple shell liquid storage tank |
-
1998
- 1998-11-25 NO NO19985502A patent/NO310319B1/en not_active IP Right Cessation
-
1999
- 1999-10-08 CN CN99812025A patent/CN1105258C/en not_active Expired - Fee Related
- 1999-10-08 KR KR1020017004625A patent/KR20010090789A/en active IP Right Grant
- 1999-10-08 EP EP99951269A patent/EP1125084A1/en not_active Withdrawn
- 1999-10-08 ID IDW00200100948A patent/ID29941A/en unknown
- 1999-10-08 WO PCT/NO1999/000307 patent/WO2000025059A1/en not_active Application Discontinuation
- 1999-10-08 BR BR9914406-9A patent/BR9914406A/en not_active IP Right Cessation
- 1999-10-08 JP JP2000578592A patent/JP2002528691A/en active Pending
- 1999-10-08 AU AU63738/99A patent/AU764312B2/en not_active Ceased
- 1999-10-08 RU RU2001112779/06A patent/RU2244204C2/en not_active IP Right Cessation
- 1999-10-08 CA CA002346842A patent/CA2346842C/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
CN1105258C (en) | 2003-04-09 |
ID29941A (en) | 2001-10-25 |
CA2346842A1 (en) | 2000-05-04 |
EP1125084A1 (en) | 2001-08-22 |
KR20010090789A (en) | 2001-10-19 |
BR9914406A (en) | 2001-06-26 |
CN1323382A (en) | 2001-11-21 |
NO985502D0 (en) | 1998-11-25 |
AU764312B2 (en) | 2003-08-14 |
NO310319B1 (en) | 2001-06-18 |
NO985502L (en) | 2000-07-17 |
WO2000025059A1 (en) | 2000-05-04 |
AU6373899A (en) | 2000-05-15 |
RU2244204C2 (en) | 2005-01-10 |
JP2002528691A (en) | 2002-09-03 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US3338010A (en) | Insulation foundation for low temperature and cryogenic storage tanks | |
US3418812A (en) | Insulating means for underground storage system | |
US3076317A (en) | Insulating foundation for cryogenic storage tank | |
CA2346842C (en) | Storage installation for liquified gases | |
US3330118A (en) | Sunken tank with floating cover for liquid gas storage | |
US3481504A (en) | Liquid storage container | |
RU2232342C1 (en) | Underground liquefied natural gas storage tank | |
US3538661A (en) | Liquid storage container | |
US5018639A (en) | Storage container for low-temperature liquids | |
US3276213A (en) | Reservoir for the underground storage of liquefied gases | |
US3562986A (en) | Liquid storage container | |
US3267685A (en) | Container for storing liquids at low temperatures | |
US3225955A (en) | Land storage for liquefied gases | |
CN209743248U (en) | Mounting structure of vertical barrel pump | |
CA1116420A (en) | Container for liquefied gas | |
US4580924A (en) | Process and device for blocking a well opening out in the ceiling of an underground cavity for low temperature storage | |
TWI812048B (en) | triple shell storage tank | |
JPS6126720Y2 (en) | ||
JPS631115Y2 (en) | ||
US4827992A (en) | Method for conducting a fluid into a rock cistern | |
JP4337168B2 (en) | Low temperature tank | |
JPH0633852B2 (en) | Double shell tank | |
SU750025A1 (en) | Tank for storing liquefied gases | |
WO2004048232A1 (en) | Sub-surface storage of liquified natural gas at near atmospheric pressure | |
RU2566180C1 (en) | Liquefied natural gas underground storage (lng us) |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
EEER | Examination request | ||
MKLA | Lapsed |