US3396539A

US3396539A - Vapor barrier means for underground storage system

Info

Publication number: US3396539A
Application number: US527288A
Authority: US
Inventors: Amanullah R Khan; Bertram E Eakin; Phillip J Anderson
Original assignee: Institute of Gas Technology
Current assignee: Gas Technology Institute
Priority date: 1966-02-14
Filing date: 1966-02-14
Publication date: 1968-08-13
Anticipated expiration: 1985-08-13
Also published as: US3407606A; ES336766A1; US3418812A; DE1533794A1; GB1180416A

Abstract

1,180,416. Liquefied gas storage chambers. INSTITUTE OF GAS TECHNOLOGY. 14 Feb., 1967 [14 Feb., 1966 (3)], No. 7040/67. Heading F4P. The floor, sides and roof of an excavated underground rock cavern 8, Fig. 3, at the bottom end of an inclined adit 3 for storing liquid methane at atmospheric pressure are first sealed at 101, 121, Fig. 4, against inflow of water, the roof and sides are then lined with foam-in-place insulation material 103, e.g. polyurethane which in turn is lined by layers 105, 106 of rigid polyurethane foam panels whilst the floor is lined by layers 107a, 106a formed of rigid polyurethane panels, and the roof sides and floor are then sealed by an impermeable barrier layer 111, e.g. of aluminum and finally the adit is closed at a point above the stored liquid level by a vapour barrier means 6 through which pass service lines. Abutting edges of the panels of layers 105, 107a are sealed by non-setting mastic whereon abutting edges of the panels of layers 106, 106a are sealed by flexible foam 113, Fig. 5, and by flexible tape. The barrier 6 comprises a doublewalled steel frame 211, Fig. 10, bolted to a concrete frame 207 set in the walls, floor and roof of the adit, and an access opening 219 in frame 211 is closed by a removable cover 223. In operation air is displaced from the cavern by inert gas delivered from a source 25 through initial cool-down spray lines 26 and the liquid fill line 30, whilst return purge gas is exhausted through a liquid withdrawal line 38 and a vapour return line 32. Initial liquid injection is through lines 26 and nozzles 28 and displaced gas returning through line 32 is flared at 48 until said return gas comprises pure methane after which the return gas is either re-liquefied at 50 or delivered to a consumer line 49. When cooldown is completed liquid methane is fed to the cavern through fill line 30 and may be withdrawn by a pump 56 discharging through a line 38 into a vaporizer 35.

Description

Aug. 13, 1968 A, R. KHAN ETAL 3,396,539

VAPOR BARRIER MEANS FOR UNDERGROUND STORAGE SYSTEM Filed Feb. 14, 1966 INVENTOR. PHILLIP J. ANDERSON AMANULLAH R. KHAN 9 BERT E. E'AK/N ,4 TTORNEYS' United States Patent 0 3,396,539 VAPOR BARRIER MEANS FUR UNDERGRGUND STORAGE SYSTEM Amanullah R. Khan, Chicago, Bertram E. Eairin, Naperville, and Phillip J. Anderson, Deeriieid, Ill., assignors to Institute of Gas Technology, a not-for-profit corporation of Illinois Filed Feb. 14, 1966, Ser. No. 527,288 6 Ciaims. (Cl. 61-.5)

ABSTRACT OF THE DISCLOSURE A vapor and liquid barrier structure mounted in an inclined adit between the atmosphere and an underground chamber used for storing liquefied gas at atmospheric pressure and cryogenic temperatures. A rigid outer frame is rigidly secured to the wall, ceiling, and floor of said adit. The outer frame includes a central aperture in which a second rigid frame is received. The second rigid frame, in turn, includes a central aperture therein which is enclosed by a removable plugging member. The joints be tween the inner and outer frames and between the inner frame and the plugging member are sealed by means for preventing passage of liquid and vapor therethrough. Insulation is contiguous with the outer frame, the inner frame, and the plugging member to substantially reduce the transfer heat from the atmospheric side of the barrier to the cryogenic liquefied gas contained within said underground chamber.

This invention relates to means for sealing the entry adit to an underground storage cavern for storing liquefied gases. In particular, the invention relates to an insulated composite concrete-metal barrier wall for placing in an adit leading to an underground rock storage cavern.

There is described in our copending application Ser. No. 527,158, filed Feb. 14, 1966, a new and improved method for storing large volumes of liquefied gases underground at substantially atmospheric pressure in a safe and economical manner. The invention described in the aforementioned application relates generally to the storage of liquefied gases in rock caverns or rock structures near the ground surface, the caverns or structures being insulated and lined to provide low evaporation rates and safe containment of the low temperature liquid gases at substantially atmospheric pressure. The caverns were designed to store liquefied natural gas but may also be used for storage of other gases which have been cooled to the liquid state at atmospheric pressures such as ethane, propane, butane as well as ammonia, carbon dioxide, argon, nitrogen and hydrogen.

The underground rock storage caverns with which the vapor barrier of this invention is particularly useful comprise a room and pillar cavern which has been excavated by means of a large inclined entry which permits rapid ingress and egress of heavy equipment for the purpose of efficient and economical excavation. The walls, roof and pillars of the cavern are coated with a moisture or water sealant and all rock surfaces are insulated with one or more layers of a foamed insulating material providing internal insulation in the cavern. One layer of the insulation, preferably the innermost layer, is coated or lined with a liquid and vapor impervious material, such as a laminate of plastic and metal foil, to prevent loss of liquid or vapor through the insulation.

The entry adit of the cavern is provided with a double bulkhead system which prohibits gas or liquid from leaking from the cavern through the adit to the ground level. The bulkhead system comprises a liquid bulkhead which serves as a weir as described in copending application Ser. No. 527,158, filed Feb. 14, 1966, and a vapor barice rier through which are provided suitable apertures for piping means for filling, emptying, relieving and instrumenting the rock cavern. Such vapor barrier means is the subject matter of this invention.

It is an object of this invention to provide a vapor barrier means in the large inclined entry adit to an underground storage cavern which means prevents leakage of vaporized gases from the cavern to atmosphere and also prevents heat loss to the cavern.

It is a further object of this invention to provide such vapor barrier means which is relatively simple of construction and which provides easy access to the cavern in the event the cavern is to be opened.

It is yet another object of this invention to provide a vapor barrier means through which may be inserted various piping means for filling, emptying, relieving and instrumenting the rock cavern in the storage of liquid gases.

Other objects of the invention will become clear as the invention is more fully described hereinafter.

In one of the important aspects of the present invention, a vapor and liquid barrier structure, mounted in an inclined adit between the atmosphere and an underground chamber used for storing liquefied gases at substantially atmospheric pressure and cryogenic temperatures includes an outer rigid frame having an enlarged central opening, suitable means for rigidly securing the outer rigid frame to the wall, floor, and top of a portion of said adit, an inner rigid frame having a central aperture, suitable means for securing the inner rigid frame within the enlarged central opening of the first rigid frame, a plugging member removably secured within the central aperture of the inner rigid frame, sealing means on the joints between the inner and outer frames and between the inner frame of the plugging member for preventing the passage of liquid and vapor therethrough, and insulation substantially contiguous with the outer frame, the inner frame, and the plugging member for substantially reducing the transfer heat from the atmospheric side of the barrier to the cryogenic liquefied gas side of the barrier.

In the drawings:

FIG. 1 is a front elevation showing the vapor sealing meglns as it appears in the inclined entry of a rock cavern; an

FIG. 2 is a top view along line 22 of FIG. 1.

Broadly speaking, the vapor barrier of this invention consists of a cast concrete frame which is keyed into the walls, floor, and roof of the inclined entry and is held to the rock surface by a plurality of anchor bolts which are embedded in the rock and extend into the concrete frame to restrict relative movement between the frame and the rock. Mounted within the concrete frame is a doublewalled metal frame which has a plurality of apertures to accommodate piping, conduits and the like and an access hole at its center sufficiently large for ingress and egress of workmen. The access hole is closed during normal operation of the cavern by a double-walled plug described hereinafter. The double-walled metal frame and plug are insulated internally to minimize heat loss between the cavern and atmosphere. The metal frame is fabricated with expansion means to allow differential movement between the concrete frame member and the metal frame member in response to thermal stresses. The metal frame is made of any material which will not exhibit brittle failure at cryogenic temperatures, preferably a suitable grade of steel. All piping and lines which pass from atmosphere into the cavern pass through the doublewalled metal frame through the above-mentioned apertures where a gas-type seal and suitable expansion and contraction means are provided on the surface of the metal frame toward the storage cavity to accommodate thermal stresses.

Referring to FIG. 1, there is shown generally at 1 in cross-section an arched dome entry adit having a rock surface. As best seen in FIG. 2, the walls of the adit are keyed at 3 by providing a circumferential groove along a substantially vertical plane. Rock bolts 5, well-known in the mining art, are driven into the walls at the base of keyed portion 3 at various points as best seen in FIG. 1. The rock bolts project perpendicularly from the rock wall and are embedded in concrete frame 7 which fills the keyed at 3 by providing a circumferential groove along a frame with a large, generally square opening 9.

Disposed within the opening 9 is a double-walled metal frame 11 provided with expansion means 13 which are simply creases projecting from the metal frame. Such expansion means permit lateral and vertical expansion and contraction of the metal wall in response to thermal stresses. Metal wall 11 is oriented in the entry adit so that the side thereof with expansion means 13 (lower side in FIG. 2) faces inwardly toward the cavern and the other side of the frame 11 faces outwardly toward atmosphere. Thus the inward side of the frame 11 is subjected to the greatest thermal stresses. Metal wall or frame 11 is secured to the concrete frame 7 by means of plates 15 which overlap opposite sides of the concrete frame 7 and wall the frame 11 and which are welded onto the metal frame 11 and bolted through the concrete frame as shown at 17.

The central portion of the metal wall or frame 11 is provided with an access hole 19 which is normally bolted closed by cooperating bolting members 30 and 31 to the metal frame 11 by means of a double-walled plug 21 as shown at 23. Both the metal frame 11 and the plug 21 are internally insulated with a suitable cryogenic insulating material 14, such as glass fibers or polyurethane foam. Through the metal wall 11 are provided apertures 22 which are adapted to accommodate piping and conduits extending from outside the cavern to within the cavern. Suitable gas sealing means and expansion joints are provided to ensure gas-tight integrity of the barrier.

The edges of the contact of concrete frame 7 and the metal wall 11 are sealed by means of vapor impervious cryogenic adhesive tape 27 which is secured to the insulation 29 provided on the internal surface of the concrete frame and on the internal surface of the rock cavern as described in copending application Ser. No. 526,983, filed Feb. 14, 1966, and to the wall of the metal wall frame 11 which faces the cavern. In addition, the contact edges between the plug 21 and the metal wall 11 are sealed by means of suitable adhesive tape 29a, such as tape 23, on the wall of 11 facing atmosphere. Such external sealing is necessary since it is not possible to seal the joints of plug 21 and frame 11 internally inasmuch as plug 21 is inserted into aperture 19 from the entry portal side or outer side of the vapor barrier.

As shown in FIGS. 1 and 2, the vapor barrier of this invention provides a simple, economical and effective means against loss of liquid or vapor materials from within the rock cavern to atmosphere. Also the barrier insulates the cavern from atmosphere. The barrier is sealed at all joints by vapor-impervious cryogenic tape and the barrier is provided with suitable expansion means so there is no possibility of rupture of joints during the thermal stresses encountered in filling or emptying the cavern. The internal portion of metal wall frame 11 is subjected to the greatest thermal stress and is therefore made of special materials which do not exhibit brittle failure at cryogenic temperatures. The outer portion of the metal frame 11 can be made of ordinary carbon steel since such portion is not subjected to high temperature changes.

It should be clear to those skilled in the art that various modifications can be made in the above described invention within the spirit of the invention which we intend to be limited solely by the appended claims.

We claim:

1. A vapor and liquid barrier structure mounted in an inclined adit and between the atmosphere and an underground chamber used for storing liquefied gases at substantially atmospheric pressure and cryogenic temperatures, said adit having surrounding walls, a floor, and a top, said structure comprising an outer rigid frame having an enlarged central opening, means for rigidly securing said outer frame to said walls, floor, and top of said adit, an inner rigid frame having a central aperture therein, means for rigidly securing said inner rigid frame within said enlarged central opening of said outer rigid frame, a plugging member, means for removably securing said plugging member within said central aperture, means for sealing the joints formed between said outer frame and said inner frame and between said inner frame and said plugging member to substantially prevent the passage of liquid and vapor therethrough, and insulating means substantially contiguous with said outer frame, said inner frame, and said plugging member to substantially reduce the transfer of heat from the atmosphere side of said barrier to the cryogenic liquefied gas side of said barrier.

2. The structure of claim 1 wherein said outer frame is formed of concrete, and said first mentioned securing means comprises a plurality of rock bolts which are embedded in both said walls, said floor, and said top, and in said concrete, and a keyed groove provided in said walls, said floor, and said top for receiving said concrete outer frame.

3. The structure of claim 1 wherein said inner frame includes means for receiving a plurality of pipes and conduits for passage thereof through said structure.

4. The structure of claim 1 wherein said insulating means comprises insulation covering the cryogenic temperature side of said outer frame, and insulation contained within said inner frame and said plugging member.

5. The structure of claim 1 wherein said inner frame and said plugging member each comprise a double-walled metal panel, and said inner frame includes means on the cryogenic side of said structure for permitting lateral and vertical expansion and contraction of said inner frame in response to thermal stresses.

6. The structure of claim 5 wherein each of said double-walled panels includes a space therein and said insulating means is received within said space of each said panels.

References Cited UNITED STATES PATENTS 2,787,125 4/1957 Benz 61-.5 2,855,757 10/1958 Meade 6l--.5 2,981,070 4/1961 Seely 61-.5 3,151,416 10/1964 Eakin et a1. 61.5 X 3,184,922 5/1965 Anton 61-.5

FOREIGN PATENTS 963,038 7/1964 Great Britain.

EARL J. WITMER, Primary Examiner.