AU2010273189A1

AU2010273189A1 - Liquefied natural gas tank

Info

Publication number: AU2010273189A1
Application number: AU2010273189A
Authority: AU
Inventors: Kenneth Peter Panitz
Original assignee: Thiess Pty Ltd
Current assignee: Thiess Pty Ltd
Priority date: 2009-07-16
Filing date: 2010-07-16
Publication date: 2012-02-09
Also published as: WO2011006213A1

Abstract

A prefabricated module for construction of an outer wall of a LNG tank, the prefabricated module comprising a vapour barrier plate, support frames connected to the vapour barrier plate, and a number of reinforcement members attached to the support frames.

Description

WO 2011/006213 PCT/AU2010/000912 1 TITLE LIQUEFIED NATURAL GAS TANK FIELD OF THE INVENTION This invention relates to a liquefied natural gas tank and 5 method of construction thereof. In particular, the invention relates to construction of the outer wall of the LNG tank. BACKGROUND TO THE INVENTION The demand for natural gas throughout the world is increasing due to its "green" classification. Liquefied natural gas (LNG) is a popular 10 form of natural gas used for both transportation and storage purposes. LNG offers an energy density comparable to petrol and diesel fuel but when utilized produces less pollution. However, it is expensive to transport and store due to the need for the cryogenic tanks. Cryogenic tanks must be used in order to maintain the natural gas at approximately -160 0 C in order to keep 15 the natural gas liquefied. LNG storage tanks are formed from an open top, inner tank which is used to store the LNG, and an outer tank. The outer tank includes a floor on which sits a circular concrete outer wall which is attached to a roof. A vapour barrier extends around the inner surface of the floor, outer wall and 20 roof. In order to erect a LNG tank, construction is commenced with the formation of the outer concrete wall using a typical jump-form insitu method. Once the concrete wall has been formed, the concrete wall vapour barrier is built adjacent the concrete wall. A roof and associated roof vapour barrier is then constructed to complete the outer tank of the LNG tank. Typically the 25 roof is constructed at ground level and then air raised into place. It is only after the roof has been raised and secured that the construction of the inner tank can take place. This method of construction of a LNG tank is time consuming, labour intensive and expensive. In order to address some of the above problems, a new method 30 of construction of a LNG tank has been developed. This method includes the erection of an outer tank vapour barrier using thicker mild steel. This produces a vapour barrier which is self supporting and of sufficient strength WO 2011/006213 PCT/AU2010/000912 2 to support a roof of the outer tank. This enables the inner tank construction to begin earlier in the program. However, construction of the structural vapour barrier adds considerable material and labour expense to the construction of the LNG tank even though it reduces project duration. 5 Accordingly, there is only a small cost reduction in the overall production of the LNG tank. Further, additional risk is endured as the structural vapour barrier must be unable to withstand high wind speeds during construction. OBJECT OF THE INVENTION It is an object of the invention to overcome or at least alleviate 10 one or more of the above disadvantages and/or provide the consumer with a useful or commercial choice. SUMMARY OF THE INVENTION In one form, although not necessarily the only or broadest form, the invention resides in a prefabricated module for construction of an outer 15 wall of a LNG tank, the prefabricated module comprising: a vapour barrier plate; at least one support frame connected to the vapour barrier plate; and a plurality of reinforcement members attached to the at least 20 one support frame. Normally the vapour barrier plate is curved. Preferably the support frame is in the form of a body able to provide additional strength to a vapour barrier plate. The body normally includes a plurality of reinforcement locating holes located through the body 25 for positioning of some of the plurality of reinforcement members. Normally the body is ladder shaped. The body may include a bottom rail and a top rail. The bottom rail and top rail may be interconnected by interconnecting plates. End plates may interconnect the top rail and the bottom rail adjacent their ends. 30 Typically the reinforcement locating holes are located through the top rail and/or the bottom rail. Normally there is also a least one stressing ducting locating WO 2011/006213 PCT/AU2010/000912 3 hole located through the body for positioning of a stressing duct. The at least one stressing duct locating hole may be located adjacent the intersection of the interconnecting plate and the bottom rail. The plurality of reinforcement members may include horizontal 5 reinforcement members and/or vertical reinforcement members. Typically only the horizontal reinforcement members or the vertical reinforcement members are attached to the support frame. The horizontal reinforcement members may include inner horizontal reinforcement members and/or outer horizontal reinforcement 10 members. The inner horizontal reinforcement members may be located through the bottom rail of the support frame. The outer horizontal reinforcement members may be located through the top rail of the support frame. The vertical reinforcement members may include inner vertical 15 reinforcement members and/or outer vertical reinforcement members. The inner vertical reinforcement members may be joined to the inner horizontal vertical members. The outer vertical reinforcement members may be joined to the outer horizontal vertical members. The prefabricated module may also include stressing ducts. 20 The stressing ducts may include horizontal stressing ducts and/or vertical stressing ducts. The horizontal stressing ducts may be located through the stressing duct locating holes. The vertical stressing ducts may be joined to the horizontal stressing ducts. In yet another form, the invention resides in a method of 25 producing a prefabricated module for use in the construction of the outer wall of a LNG tank, the method including the steps: connecting a plurality of support frames to a vapour barrier plate, and; connecting a plurality of reinforcement members to the plurality 30 of the support frames. The method may further include one or more of the steps of: locating a plurality of reinforcement members through the WO 2011/006213 PCT/AU2010/000912 4 support frame; and locating a plurality of stressing ducts through the support frame. The method may still further include the step of using a prefabrication jig to place the support frames onto the vapour barrier. 5 In yet another form, the invention resides in an outer wall of an LNG tank comprising: a plurality of prefabricated modules located adjacent one another, each prefabricated module including a vapour barrier plate; at least one support frame connected to the vapour barrier plate; and a plurality of 10 reinforcement members attached to the at least one support frame; and a settable material located adjacent the vapour barrier plate and covering the support frames and reinforcing members. The prefabricated module may include the features specified above. 15 The settable material may be a cementitious material. Preferably the cementitious material is concrete. In yet another form, the invention resides in a method of producing an outer wall of a LNG tank, the method including the steps: locating a plurality of reinforcement modules adjacent each 20 other; each prefabricated module including a vapour barrier plate, at least one support frame connected to the vapour barrier plate; and a plurality of reinforcement members attached to the at least one support frame; and pouring a settable material between the vapour barrier and a shutter spaced a distance from the vapour barrier. 25 Normally the settable material settable material is located adjacent the vapour barrier plate and covers the support frames and reinforcing members. In yet another form, the invention resides in a support frame for a reinforcement module, the support frame including: 30 a body able to provide additional strength to a vapour barrier plate; and a plurality of reinforcement locating holes located through the WO 2011/006213 PCT/AU2010/000912 5 body for positioning of a plurality of reinforcement members. Normally the body is ladder shaped. The body may include a bottom rail and a top rail. The bottom rail and top rail may be interconnected by interconnecting plates. End plates may interconnect the top rail and the 5 bottom rail adjacent their ends. Typically the locating holes are located through the top rail and/or the bottom rail. Normally there is also at least one stressing duct locating hole located through the body for positioning of a stressing duct. The at least one 10 stressing duct locating hole may be located adjacent the intersection of an interconnecting plate and the bottom rail. BRIEF DESCRIPTION OF THE DRAWINGS An embodiment, by way of example only, will be described with reference to the accompanying drawings, wherein: 15 FIG. 1 is a perspective view of a LNG tank constructed using prefabricated modules; FIG. 2 is a perspective view of a prefabricated module for use in the construction of an outer wall of the LNG tank shown in FIG. 1; FIG. 3a is a perspective view of a vapour barrier with welded 20 support frames located in a fabrication jig; FIG. 3b is a top view of a vapour barrier with welded support frames located in a fabrication jig; FIG. 3c is a side view of a vapour barrier with welded support frames located in a fabrication jig; 25 FIG. 4a is a perspective view of inner vertical reinforcement being placed on the vapour barrier plate; FIG. 4b is a top view of inner vertical reinforcement being placed on the vapour barrier plate; FIG. 4c is a side view of inner vertical reinforcement being 30 placed on the vapour barrier plate; FIG. 5a is a perspective view of horizontal reinforcement being located through the support frames; WO 2011/006213 PCT/AU2010/000912 6 FIG. 5b is a top view of horizontal reinforcement being located through the support frames; FIG. 5c is a side view of horizontal reinforcement being located through the support frames; 5 FIG. 6a is a perspective view of horizontal stressing ducts being located over the holes on all stressing ducts; FIG. 6b is a top view of horizontal stressing ducts being located over the holes on all stressing ducts; FIG. 6c is a side view of horizontal stressing ducts being 10 located over the holes on all stressing ducts; FIG. 7a is a perspective view of vertical stressing ducts being located over the holes on all stressing ducts; FIG. 7b is a top view of vertical stressing ducts being located over the holes on all stressing ducts; 15 FIG. 7c is a side view of vertical stressing ducts being located over the holes on all stressing ducts; FIG. 8a is a perspective view of outer horizontal reinforcement being located through the support frames; FIG. 8b is a top view of outer horizontal reinforcement being 20 located through the support frames; FIG. 8c is a side view of outer horizontal reinforcement being located through the support frames; FIG. 9a is a perspective view of outer vertical reinforcement being laid on top of the outer horizontal reinforcement; 25 FIG. 9b is a top view of outer vertical reinforcement being laid on top of the outer horizontal reinforcement; FIG. 9c is a side view of outer vertical reinforcement being laid on top of the outer horizontal reinforcement; FIG. 10 is a perspective view of a completed prefabricated 30 module with lifting beam; FIG. 11 a is a perspective view of a partially completed outer wall of a LNG tank; WO 2011/006213 PCT/AU2010/000912 7 FIG. 11b is a side view of a partially completed outer wall of a LNG tank; FIG. 12a is a perspective view of a partially completed a LNG tank with additional upper prefabricated modules being added; 5 FIG. 12b is a side view of a partially completed a LNG tank with additional upper prefabricated modules being added; FIG. 13a is a perspective view of a partially completed of a LNG tank with shutters added; FIG. 13b is a side view of a partially completed of a LNG tank 10 with shutters added; FIG. 14a is a perspective view of a partially completed outer wall of a LNG tank after concrete has been poured to the height of the shutters; FIG. 14b is a side view of a partially completed outer wall of a 15 LNG tank after concrete has been poured to the height of the shutters; FIG. 15a is a perspective view of a partially completed outer wall of a LNG tank after concrete has been poured with the shutters at a higher height; FIG.15b is a side view of a partially completed outer wall of a 20 LNG tank after concrete has been poured with the shutters at a higher height; FIG. 16a is a perspective view of a partially completed outer wall of a LNG tank after concrete has been poured with the shutters at still a higher height; FIG.16b is a side view of a partially completed outer wall of a 25 LNG tank after concrete has been poured with the shutters at still a higher height; FIG. 17a is a perspective view of a partially completed outer wall of a LNG tank after concrete has been poured with the shutters at yet still a higher height; 30 FIG.17b is a side view of a partially completed outer wall of a LNG tank after concrete has been poured with the shutters at yet still a higher height; WO 2011/006213 PCT/AU2010/000912 8 FIG. 18a is a perspective view of a partially completed outer wall of a LNG tank after concrete has been poured with the shutters at a higher height again; FIG.18b is a side view of a partially completed outer wall of a 5 LNG tank after concrete has been poured with the shutters at a higher height again; FIG. 19a is a side view of a support frame used in the prefabricated module of FIG. 2; FIG. 19b is a detail view of a support frame used in the 10 prefabricated module of FIG. 2; FIG. 19c is a detail view of a two support frames being joined together; FIG. 20 is a perspective view of a shutter; FIG. 21a is a perspective view of a prefabricated "pilstar" 15 module for use in the construction of an outer wall of the LNG tank; FIG. 21b is a side view view of a prefabricated "pilstar" module for use in the construction of an outer wall of the LNG tank; and FIG. 21c is a top view of a prefabricated "pilstar" module for use in the construction of an outer wall of the LNG tank. 20 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a perspective view of an LNG tank 10. The perspective view shows a cylindrical outer wall 11 with an attached roof 12 forming an outer tank of the LNG tank. The outer wall is formed from a series of prefabricated modules 100. 25 FIG. 2 shows a cutaway of part of the outer wall 11 revealing a prefabricated module 100 embedded in concrete 110. The outer wall 11 is formed by several hundred prefabricated modules 100 which are joined together. Each prefabricated module 100 includes a vapour barrier plate 120, support frames 130, inner vertical reinforcement bars 140, inner 30 horizontal reinforcement bars 150, outer vertical reinforcement bars 160, outer horizontal reinforcement bars 170, horizontal stressing ducts 180 and vertical stressing ducts 190.

WO 2011/006213 PCT/AU2010/000912 9 The vapour barrier plate 120 is 6 metres wide by 4 metres high. However, it should be appreciated that the dimensions of the vapour barrier plate 120 may be varied in accordance with design. The thickness of the vapour barrier plate 120 again will be dependent upon design features, such 5 as pour size, expected site temperature, pour rate and mix design. The vapour barrier plate 120 is made from mild steel. The support frames 130 are connected to the vapour barrier plate 120. The support frames 130, shown in more detail in FIGS. 19a to 19c, include a ladder shaped body 131 having a top rail 132, bottom rail 133, 10 end plates 134 and interconnecting plates 135. The top rail 132 and bottom rail 133 have a series of reinforcement locating holes 136 that extend along the length of the respective top rail 132 and bottom rail 133. A series of stressing duct locating holes 137 are located adjacent the intersection of the interconnecting plates 135 and bottom plates 133. The end plates 135 have 15 joining holes 138 that extend through the end plates 135 to allow adjacent prefabricated modules 100 to be aligned and joined to each other. A series threaded shutter 139 attachment holes are located along the top rail for attachment of shutters. The inner vertical reinforcement bars 140, inner horizontal 20 reinforcement bars 150, outer vertical reinforcement bars 160 and outer horizontal reinforcement bars 170 are all standard reinforcement bars used in reinforced concrete. The inner vertical reinforcement bars 140 and the outer vertical reinforcement bars 160 are longer than the width of the vapour barrier plate 120 whilst the inner horizontal reinforcement bars 150 and the 25 outer horizontal reinforcement bars 170 are slightly shorter than the length of the vapour barrier plate 120. The inner horizontal reinforcement bars 150 are located through the reinforcement locating holes 136 located in the bottom rails 133 of the support frames 130 whilst the outer horizontal reinforcement bars 170 30 are located through the reinforcement locating holes 136 in the top rails 132 of the support frames 130. Both the inner horizontal reinforcement bars 150 and the outer horizontal reinforcement bars 170 are tied to the support WO 2011/006213 PCT/AU2010/000912 10 frames 130 with some of the outer horizontal reinforcement bars 170 being welded to support frames 130. The inner vertical reinforcement bars 140 are tied to the inner horizontal reinforcement bars 150 whilst the outer vertical reinforcement bars 160 are tied to the outer horizontal reinforcement bars 5 170. The horizontal stressing ducts 180 and the vertical stressing ducts 190 are made from hollow galvanized metal tube which has a spiral tread pressed along its length. However, it should be appreciated that other types of stressing duct materials may be used. The horizontal stressing 10 ducts 180 are slightly shorter than the length of the vapour barrier plate 120 whilst the vertical stressing ducts 190 are slightly shorter than the width of the vapour barrier plate 120. The horizontal stressing ducts 180 are located through the stressing duct locating holes 137 located adjacent the intersection of the 15 interconnecting plates 135 and bottom plate 137. The vertical stressing ducts 190 are tied to the horizontal stressing ducts 180. In order to produce a prefabricated module 100, the vapour barrier plate 120 is located on a prefabrication jig 20. Once the vapour barrier plate 120 is positioned on the prefabrication jig 20, four support 20 frames 130 are located in predetermined positions across the width of the vapour barrier plate 120 as shown in FIGS. 3a to 3c. The joining holes 138 in the end plates are aligned with associated holes 21 in brackets 22 and the prefabrication jig 20 to ensure that each of the support frames 130 are in their required position. This method of placing the support frames 130 on the 25 vapour barrier plate 120 ensures repeatability for each prefabricated module 100. The support frames 130 are then welded to the vapour barrier plate 120 along the bottom rail 133 of the support frame 130. The next step is to place inner vertical reinforcement bars 140 atop the vapour barrier plate 120 as shown in FIGS. 4a to 4c. As the length 30 of the vertical reinforcement bars 140 is longer than the length of the vapour barrier plate 120, an end of the inner vertical reinforcement bars 140 extends past an end of the vapour barrier plate 120. The inner vertical reinforcement WO 2011/006213 PCT/AU2010/000912 11 bars 140 are slightly offset with respect to "true vertical" using guides (not shown). This offsetting of the inner vertical reinforcement bars 140 assists in alignment of adjacent prefabricated modules 100 when positioned on top of each other. 5 After the inner vertical reinforcement bars 140 are positioned on top of the vapour barrier plate 120, inner horizontal reinforcement bars 150 are installed as shown in FIGS. 5a to Sc. This installation is conducted by locating the inner horizontal reinforcement bars 150 through the reinforcement locating holes 136 located in the bottom rail 133 of the support 10 frames 130. This ensures that the inner horizontal reinforcement bars 150 are located precisely for each prefabricated module 100. The inner horizontal reinforcement bars 150 are then secured to the support frames 130 by tie wire. The inner vertical reinforcement bars 140 are then secured to the inner horizontal reinforcement bars 150 also by tie wire. 15 FIGS. 6a to 6c show horizontal stressing ducts 180 being located through the horizontal stressing duct locating holes 137 formed within the support frames 130. FIGS. 7a to 7c show vertical stressing ducts 190 located on top of the horizontal stressing ducts 180. Once the vertical stressing ducts 190 are placed on top of the horizontal stressing ducts 180, 20 they are secured in place using metal ties. Alignment guides (not shown) are used for this purpose. The next step is to locate outer horizontal reinforcement bars 170 through reinforcement locating holes 136 in the top rail 132 of the support frames 130 as shown in FIGS. 8a to 8c. Again, the outer horizontal 25 reinforcement bars 170 are secured to the support frame 130 by tie wire. However, it is envisaged that some of the outer horizontal reinforcement bars 170 may be welded to the support frames 130. This is to assist in preventing distortion of the prefabricated modules 100 during both transport and installation. 30 Once the outer horizontal reinforcement bar 170 is in place, outer vertical reinforcement bars 160 are placed atop the outer horizontal reinforcement bars 170 and secured with tie wire as shown in FIGS. 9a to 9c.

WO 2011/006213 PCT/AU2010/000912 12 Again, the outer vertical reinforcement bars 160 are offset in a similar manner to the inner vertical reinforcement bars 140 to ensure that each outer vertical reinforcement bar 160 can align with adjacent outer vertical reinforcement bars 160 in a lower prefabricated module 100 without clashing. 5 The reinforcement module 100 is then completed, as shown in FIG. 10, and therefore ready for transportation and installation. A lifting beam 195 is used to lift the reinforcement module at this stage. The lifting beam 195 is attached to the end plates of the support frames using fasteners (not shown) which pass through the joining holes 138 and the lifting beam 10 195. FIGS. 11a and 11b shows a partially completed partial outer wall 11 of a LNG tank. That is, the lower part of the outer wall 11 a has been completed. The lower part of outer wall 11 shown uses two lower prefabricated modules100a which have been embedded in concrete. That is, 15 the support frames 130, inner vertical reinforcement bars 140, inner horizontal reinforcement bars 150, outer vertical reinforcement bars 160, outer horizontal reinforcement bars 170, horizontal stressing ducts 180, and vertical stressing ducts 190 have been covered in concrete. It should be appreciated that the inner vertical reinforcement bars 140, outer vertical 20 reinforcement bars 160, vertical stressing ducts 190 and support frames 130 of the lower prefabricated modules 100a all partially extend out of the concrete 200 to be joined to an upper prefabricated module 100b. The next step in erecting of the outer wall 11 of the LNG tank is to locate upper prefabricated modules 100b on to the lower prefabricated 25 modules 100a and then join the lower prefabricated modules 100a and upper prefabricate modules 100b together as shown in FIGS. 12a to 12b. The first step is to align the end plates 134 of the support frames 130 of the lower prefabricated modules 1 00a with end plates 134 of the support frames 130 of the upper prefabricated modules 100b as shown in FIG. 19c. Fasteners are 30 then used to fasten the end plates 134 together. As the inner vertical reinforcement bars 140 and outer vertical reinforcement bars 160 are offset on each prefabricated module 100a, the WO 2011/006213 PCT/AU2010/000912 13 inner vertical reinforcement bars 140 and the outer vertical reinforcement bars 160 of the lower prefabricated module 100a are located adjacent the inner vertical reinforcement bars 140 and the outer vertical reinforcement bars 160 of the upper prefabricated module 100b. The inner vertical 5 reinforcement bars 140 and outer vertical reinforcement bars 160 can then easily be tied together using tie wire. Similarly, as the vertical stressing ducts 190 of both the lower prefabricated modules 100a and the upper prefabricated modules 100b are located adjacent each other, couplers (not shown) and duct tape (not shown) 10 are simply used to join the vertical stressing ducts 190 together. The next step is to join adjacent upper prefabricated modules 100b together. This involves joining the inner horizontal reinforcement bars 150 and outer horizontal reinforcement bars 170 of adjacent upper prefabricated modules 100b together using lacer bars 220 as shown in 15 FIG. 2. Similarly, as the horizontal stressing ducts 180 of adjacent upper prefabricated modules 100b are located adjacent each other, couplers (not shown) and duct tape (not shown) are simply used to join the horizontal stressing ducts 180 together. Once the joining of both lower prefabricated modules 100a and 20 the upper prefabricated modules 100b, and adjacent upper prefabricated modules 100b has been completed, external shutters 210 are located over the reinforcement modules 100a and 100b as shown is FIGS. 13a and 13b. The shutters 210, as shown in more detail in FIG. 20, are relatively short (compared to standard height shutters) and are made of 25 aluminum. This enables a team of 3 men to assemble and disassemble the shutters 210 removing the need for a crane. The shutters 210 are attached by six threaded wing nuts 211 to the reinforcement module 100. Four wing nuts 211 are attached to the reinforcement module 100 via shutter attachment holes 139 which form part 30 of the support frame 130. These wing nuts 211 are located in the corners of the shutters 210. The other two wind nuts 211 are attached to the outer vertical reinforcement bars using a standard J-bar arrangement. Spacers WO 2011/006213 PCT/AU2010/000912 14 212 are used on the ends of each of the wing nuts to ensure the correct outer wall thickness. The shutters are attached to each other using a standard dog and wedge arrangement 213. After the shutters 210 are in place, concrete is poured between 5 the shutters 210 and the vapour barrier plates 120 as shown in FIGS. 14a to 14b. It should be appreciated that only a section of the outer wall 11 is shown. During a pour, the entire circumference of the outer wall 11 is poured at once. Hence, shutters 210 extend around the entire circumference of the outer wall 11. Accordingly, the height of the pours may only be relatively 10 short but the volume of concrete pour is relatively standard. Once the concrete is sufficiently cured, the shutters 210 are moved upwardly and the process repeated as shown in FIGS. 15a and 15b through FIGS. 18a to 18b. At each upward movement of each shutter 210, what was the old upper shutter attachment hole is now the new lower shutter 15 attachment hole. This ensures quick and accurate placement of the shutters 210 at each height change. It should also be appreciated that the shutter attachment holes 139 are also used to support the working platforms 230. Additional prefabricated modules 100 can then be added, as described above, to increase the height of the outer wall 11 until the desired 20 height of the outer wall 11 is achieved. It should be appreciated that prefabricated modules may be varied depend in requirements. For example, FIGS. 21a to 21c show prefabricated "Pilistar" module 101 which is used for post-stressing the outer wall. It would be appreciated by persons skilled in the art that "pilstars" have 25 been used for post-stressing of outer walls of LNG tanks for some time. The prefabricated "pilistar" module has all of the components of a standard prefabricated module 100 except that the some of the support frames 130 extend further outwardly from the vapour barrier 120, the outer horizontal reinforcement bars 170 are not straight and bend to correspond to the 30 support frames 130, and the horizontal stressing ducts 180 terminate at a front face of the prefabricated "pilistar" module. The prefabricated "pilistar" modules are typically located at 0, 90, 180 and 270 degrees of the outer wall.

WO 2011/006213 PCT/AU2010/000912 15 The method of constructing an outer wall using prefabricated modules provides definite advantages. Firstly, the prefabricated modules can be produce offsite and transported to the site. This allows for saving in both time and labour costs. Further, the duration of the build time for the 5 outer wall can be shortened. The prefabricated modules can be produced at the same time (or ahead of time) as the outer wall is being erected. It should be appreciated that various other changes and modifications may be made to the embodiment described without departing from the spirit or scope of the invention.

Claims

1. A prefabricated module for construction of an outer wall of a LNG tank, the prefabricated module comprising: a vapour barrier plate; 5 at least one support frame connected to the vapour barrier plate; and a plurality of reinforcement members attached to the at least one support frame.

2. The prefabricated module of claim 1 wherein the vapour barrier is 10 curved.

3. The prefabricated module of claim 1 or claim 2 wherein the support frame is in the form of a body which provides additional strength to the vapour barrier plate.

4. The prefabricated module of claim 3 wherein the body includes a 15 plurality of reinforcement locating holes located through the body.

5. The prefabricated module of claim 3 or claim 4 wherein the body is ladder shaped.

6. The prefabricated module of any one of claims 3 to 5 wherein the body includes a bottom rail and a top rail. 20

7. The prefabricated module of claim 6 wherein the bottom rail and top rail are interconnected by interconnecting plates.

8. The prefabricated module of any one of claims 3 to 7 wherein end plates interconnect the top rail and the bottom rail adjacent their ends.

9. The prefabricated module of any one of claims 6 to 8 wherein the 25 reinforcement locating holes are located through the top rail and/or the bottom rail.

10. The prefabricated module of any one of claims 3 to 9 wherein there is also a least one stressing ducting locating hole located through the body

11. The prefabricated module of claims 10 wherein the at least one 30 stressing duct locating hole is located adjacent the intersection of the interconnecting plate and the bottom rail.

12. The prefabricated module of any one of the preceding claims wherein WO 2011/006213 PCT/AU2010/000912 17 the plurality of reinforcement members include horizontal reinforcement members and/or vertical reinforcement members.

13. The prefabricated module of claim 12 wherein only the horizontal reinforcement members or the vertical reinforcement members are attached 5 to the support frame.

14. The prefabricated module of claim 12 or claim 13 wherein the horizontal reinforcement members include inner horizontal reinforcement members and/or outer horizontal reinforcement members.

15. The prefabricated module of claim 14 wherein the inner horizontal 10 reinforcement members are located through the bottom rail of the support frame.

16. The prefabricated module of claim 14 or 15 wherein the outer horizontal reinforcement members are located through the top rail of the support frame. 15

17. The prefabricated module of any one of claims 12 to 16 wherein the vertical reinforcement members include inner vertical reinforcement members and/or outer vertical reinforcement members.

18. The prefabricated module of claim 17 wherein the inner vertical reinforcement members are joined to the inner horizontal vertical members. 20

19. The prefabricated module of claim 17 or 18 wherein the outer vertical reinforcement members are joined to the outer horizontal vertical members.

20. The prefabricated module of any one of the preceding claims also including stressing ducts.

21. The prefabricated module of claim 20 wherein the stressing ducts 25 include horizontal stressing ducts and/or vertical stressing ducts.

22. The prefabricated module of claim 21 wherein the horizontal stressing ducts are located through the stressing duct locating holes.

23. The prefabricated module of claim 21 or 22 wherein the vertical stressing ducts are joined to the horizontal stressing ducts. 30

24. An outer wall of an LNG tank comprising: a plurality of prefabricated modules located adjacent one another, each prefabricated module including a vapour barrier plate; at least WO 2011/006213 PCT/AU2010/000912 18 one support frame connected to the vapour barrier plate; and a plurality of reinforcement members attached to the at least one support frame; and a settable material located adjacent the vapour barrier plate and covering the support frames and reinforcing members. 5

25. The outer wall of an LNG tank as claimed in claim 24 wherein the vapour barrier of at least one of the prefabricated modules is curved.

26. The outer wall of an LNG tank as claimed in claim 24 or claim 25 wherein the support frame is in the form of a body which provides additional strength to the vapour barrier plate. 10

27. The outer wall of an LNG tank of claim 26 wherein the body includes a plurality of reinforcement locating holes located through the body.

28. The outer wall of an LNG tank as claimed in claim 26 or claim 27 wherein the body is ladder shaped.

29. The outer wall of an LNG tank as claimed in any one of claims 26 to 15 28 wherein the body includes a bottom rail and a top rail.

30. The outer wall of an LNG tank as claimed in claim 29 wherein the bottom rail and top rail are interconnected by interconnecting plates.

31. The outer wall of an LNG tank as claimed in any one of claims 26 to 30 wherein end plates interconnect the top rail and the bottom rail adjacent 20 their ends.

32. The outer wall of an LNG tank as claimed in any one of claims 29 to 31 wherein the reinforcement locating holes are located through the top rail and/or the bottom rail.

33. The outer wall of an LNG tank as claimed in any one of claims 26 to 25 32 wherein there is also a least one stressing ducting locating hole located through the body

34. The outer wall of an LNG tank as claimed in claims 33 wherein the at least one stressing duct locating hole is located adjacent the intersection of the interconnecting plate and the bottom rail. 30

35. The outer wall of an LNG tank as claimed in any one claims 23 to 34 wherein the plurality of reinforcement members include horizontal reinforcement members and/or vertical reinforcement members. WO 2011/006213 PCT/AU2010/000912 19

36. The outer wall of an LNG tank as claimed in claim 35 wherein only the horizontal reinforcement members or the vertical reinforcement members are attached to the support frame.

37. The outer wall of an LNG tank as claimed in claim 35 or claim 36 5 wherein the horizontal reinforcement members include inner horizontal reinforcement members and/or outer horizontal reinforcement members.

38. The outer wall of an LNG tank as claimed in claim 37 wherein the inner horizontal reinforcement members are located through the bottom rail of the support frame. 10

39. The outer wall of an LNG tank as claimed in claim 37 or 38 wherein the outer horizontal reinforcement members are located through the top rail of the support frame.

40. The outer wall of an LNG tank as claimed in any one of claims 35 to 39 wherein the vertical reinforcement members include inner vertical 15 reinforcement members and/or outer vertical reinforcement members.

41. The outer wall of an LNG tank as claimed in claim 40 wherein the inner vertical reinforcement members are joined to the inner horizontal vertical members.

42. The outer wall of an LNG tank as claimed in claim 40 or 41 wherein 20 the outer vertical reinforcement members are joined to the outer horizontal vertical members.

43. The outer wall of an LNG tank as claimed in any one of claims 23 to 42 wherein at least of the prefabricated modules also includes stressing ducts. 25

44. The outer wall of an LNG tank as claimed in claim 43 wherein the stressing ducts include horizontal stressing ducts and/or vertical stressing ducts.

45. The outer wall of an LNG tank as claimed in claim 44 wherein the horizontal stressing ducts are located through the stressing duct locating 30 holes.

46. The outer wall of an LNG tank as claimed in claim 44 or 45 wherein the vertical stressing ducts are joined to the horizontal stressing ducts. WO 2011/006213 PCT/AU2010/000912 20

47. The outer wall of an LNG tank as claimed in any one of claims 23 to 46 wherein the settable material is a cementitious material.

48. The outer wall of an LNG tank as claimed in claim 47 wherein the cementitious material is concrete. 5

49. A method of producing a prefabricated module for use in the construction of the outer wall of a LNG tank, the method including the steps: connecting a plurality of support frames to a vapour barrier plate, and; connecting a plurality of reinforcement members to the plurality 10 of the support frames.

50. The method of claim 49 further including the step of locating a plurality of reinforcement members through the support frame.

51. The method of claim 49 or 50 further including the step of locating a plurality of stressing ducts through the support frame. 15

52. The method of any one of claims 49 to 51 further including the step of using a prefabrication jig to place the support frames onto the vapour barrier.

53. A method of producing an outer wall of a LNG tank, the method including the steps: locating a plurality of reinforcement modules adjacent each 20 other; each prefabricated module including a vapour barrier plate, at least one support frame connected to the vapour barrier plate; and a plurality of reinforcement members attached to the at least one support frame; and pouring a settable material between the vapour barrier and a shutter spaced a distance from the vapour barrier. 25

54. The method of claim 53 wherein the settable material is located adjacent the vapour barrier plate and covers the support frames and reinforcing members.

55. A support frame for a reinforcement module, the support frame including: 30 a body able to provide additional strength to a vapour barrier plate; and a plurality of reinforcement locating holes located through the WO 2011/006213 PCT/AU2010/000912 21 body for positioning of a plurality of reinforcement members.

56. The support frame of claim 55 wherein the body is ladder shaped.

57. The support frame of claim 56 where the body includes a bottom rail and a top rail. 5

58. The support frame of claim 57 wherein the bottom rail and top rail are interconnected by interconnecting plates.

59. The support frame of claim 57 or 58 wherein end plates interconnect the top rail and the bottom rail adjacent their ends.

60. The support frame of any one of claims 57 to 59 wherein the locating 10 holes are located through the top rail and/or the bottom rail.

61. The support frame of any one of claims 55 to 60 including at least one stressing duct locating hole located through the body.

62. The support frame of claim 61 wherein the at least one stressing duct locating hole may be located adjacent the intersection of an interconnecting 15 plate and the bottom rail.