DE1903431A1 - Safety container for liquid gases - Google Patents

Abstract

Safety container for liquid gases under normal or high pressure and at environmental temperature where there is an inner storage container, open at the top, in an appropriate material; an outer safety container which surrounds the inner container, is separated from it by an annular gap; has a spherical roof of the same appropriate material and has a very effective thermal insulation. There is multi plate insulation between the floors of the inner container and the outer safety container.

Description

METALLGESELLSCHAFT Frankfurt / M., Jan. 22, 1969

Aktiengesellschaft DrWer / EV

Prov. _No. 6! O ₈ 1903431

Safety storage for the storage of liquefied gases and processes too its commissioning

As the gas supply industry from supplying individual communities When gas from local gas coking plants, the gas stations, switched to long-distance gas distribution, many of these gas stations remained in operation, admittedly with reduced production in order to cover the peak demand in the local gas network.

Due to the progressive conversion of the long-distance gas supply to natural gas, which consists mainly of methane, meeting peak demand has become more difficult because there are not enough suitable exchange gases Quantities are available.

The gas supply industry is therefore switching to low-consumption Times to liquefy natural gas and store it in a liquid state. Liquefied natural gas is produced from this supply as required pumped out and evaporated again in a special system.

The well-known large storage facilities for liquefied gases are double-walled Containers with high quality thermal insulation between the walls

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Contain.-The inner container, which is used to hold the liquefied gas, must be made of a cold-tough metallic material are «For the outer container, which is used to hold and protect the insulating material, and which is approximately at ambient temperature no material of particular cold strength is required.

Various forms of Ausführungski are known for this basic structure. For example, the inner container comes with a insulated self-supporting spherical roof closed. In another Embodiment, the self-supporting spherical roof of the inner container is replaced by a flat suspended ceiling that is attached to the spherical roof of the outer container is suspended and provided with ventilation openings. The outer container and the one between the two containers, Space filled with insulating material stand under the generated by the evaporation of the stored liquefied gas Gas pressure. The outer container can be created as a prestressed concrete construction or a combination of prestressed concrete and steel elements be. Such storage tanks can be erected on level ground and, if necessary, surrounded by a heaped earth wall will. But they can also be buried up to a considerable part of their height.

All these known embodiments have in common that they have only one liquid-tight inner container. '

With the current state of material technology and welding technology and with the experience gained in large container construction the known liquefied gas storage in their various embodiments apply as operationally reliable.

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For the construction of such liquefied gas storage facilities in densely populated areas, especially in the industrial conurbations, in which the peak demand usually has a structure peculiar to them, there are still some concerns. Among other things, they result from thinking through the following hazardous situation; If the inner container, which is intended to hold the liquefied gas, for some reason leaks so much that substantial quantities of the liquefied gas get into the space between the outer container, then a sudden increase in pressure will occur in the storage system. At the touch of the liquefied gas with the warmer zones of the insulation and with the end on the ambient temperature outer container will namely normal, be on heat supply from the surroundings resting evaporator ungsrate increase by leaps and bounds "The amount of gas formed are located in an order of magnitude _fl with the means provided for normal operation, namely by diverting the gas via safety valves to a flare, is no longer controllable. As a result of the sudden increase in pressure and or, or stresses under the influence of heat, the outer container can tear. In such a dangerous case, the uncontrollable escape of a large gas cloud into the environment is to be feared. Since the specific weight of the cold gas is greater than that of the surrounding air, the occurrence of ignitable gas-air Ge mi see near the ground must also be expected within a larger radius of the damaged container.

The invention is directed to the known container constructions to be supplemented by a new security element, which mitigates the dangers caused by an increased amount of evaporation gas with im Relation to the possible consequences of economically viable means largely restricts, and that includes the commissioning of the storage facility

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simplified and facilitated by effective pre-cooling.

The invention relates to a multi-walled insulated container for the storage of liquefied gases under normal or moderately increased pressure and at significantly below the ambient temperature lying temperatures,

The insulating container according to the invention is characterized by a Open-top storage tank ™ made of tough material ter for receiving the liquefied gas, through an outer safety container surrounding the storage container at a distance from an annular gap with a spherical roof, which is also made of cold-resistant material and has a highly heat-insulating insulation on the outside are surrounded by several layers of staggered Joints of isoliex panels arranged one above the other provide stable insulation between the floors of the two containers.

The floor insulation should be placed between the individual layers of panels it is advisable to insert continuous, dense foils.

P In the annulus between the walls of the two containers are through

the roof a dip tube, expediently several dip tubes inserted, which open at a short distance above the insulating floor in the annular space. To pre-cool the container for commissioning, use Liquefied gas is passed through these pipes into the annular space and evaporated there while cooling the container walls. For this pre-cooling is expediently a liquefied inert gas, preferably nitrogen, used. The gas mixture created by the evaporation is discharged through the drainage nozzle in the container roof. For support and can accelerate the pre-cooling and displace the air

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expediently liquefied inert gas also, in the inner storage container are given. After the inner container has been rinsed free of air, further cooling can be achieved with liquefied material to be stored Gas. Accordingly, the subject matter of the invention also includes a method for putting the storage container into operation. This method is characterized in that the pre-cooling is carried out by filling a liquefied inert gas, preferably nitrogen, into the Annular gap and into the storage tank and evaporation of the liquefied Inert gas is carried out until the air is completely displaced and that then further cooling when filling the storage container takes place with the liquefied gas to be stored.

After the storage unit has been put into operation, the immersion pipes are used in the annulus to discharge the gas that is created by the constant evaporation of the stored quantity. The amount intended to be consumed the liquefied gas is liquid through a dip tube in the roof by means of a pump to an evaporation system (not shown) promoted.

Because the annular space between the container walls is free of insulating material and is also in communication with the gas space above the level of the stored liquid under the spherical roof the insulating effect of this annulus can be neglected, especially since the flow of cold vaporized gas is constant in the operating state goes. The jacket of the outer containment is through it at a temperature that is not significantly above the evaporation temperature of the stored liquid.

The thermal insulation of the storage container according to the invention is applied from the outside to the safety container and the spherical roof.

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It usually consists of a bulk powder made of mineral material or a stuffing pack of mineral wool.

The load-bearing insulation between the two container bottoms is made of insulating panels made of plastic foam or cellulose glass with a liquid-tight structure. the Panels are laid in several layers, with the joints of adjacent layers being offset from one another. The joints will be coated with a cold viscous sealant. In addition, you can ™ Continuous foils can still be laid between individual panel layers. This guarantees that there is no liquid can get through the insulating layer to the bottom of the outer protective container. This soil is related to cold strength The requirements of the material are not as high as those of the Coat the containment so that it is also made of normal. Steel can be made.

As a result of a leak or a tear from the inner spout escaping liquid will collect in the annulus, as the temperature in this is not significantly above the boiling point of the P of the liquefied gas is located, the one escaping through the immersion pipes The amount of gas initially increased somewhat, but in no way threatening. «After a short time it reappears thermal equilibrium, which reduces the amount of gas to evaporate approximately to the initial value. The memory also remains with liquid-filled. Annular gap ready for operation. The vaporization gas is then taken directly from the gas space above the liquid level withdrawn through a gas discharge nozzle with a shut-off valve

Appropriately, a preferably pneumatically acting in the annulus

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The liquid level indicator is arranged, which can be recognized at any time lets whether and how much liquid has accumulated at the bottom of the annulus.

In the drawings are two embodiments of the invention Storage container for example and shown schematically.

Fig. 1 is a half-sided vertical section through a storage tank erected on the ground.

Fig. 2 is a half-side vertical section through a partially buried one Storage tank with outer concrete ring wall and poured out Earth wall. Corresponding parts are shown in both figures are given the same reference numerals.

In both embodiments, 1 is the inner container for receiving of the liquefied gas, 2 is the containment that comes with the Roof 6 is connected «3 is the insulating layer with which the containment and the roof are surrounded on the outside. 4 is a wrap for protecting and fixing the insulating layer. In the embodiment of FIG. 1, it consists of sheet metal on both sides in a known manner with a paint or other protective layers is provided * In the embodiment according to FIG. 2, this can Enclosure in the cylindrical part of the container can be supplemented or replaced by a concrete wall 14.

Between the cylinder jackets of the two containers 1 and 2 is the Annular space 5 left free. Ih these are from above through the roof 6 the dip tubes 7 introduced. With 8 is arranged in the annular space 5 Liquid level indicator designated. 9 denotes the viable Isoliei. L "Ischen, the bottoms of containers 1 and 2, which, like

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can be seen, consists of several board layers with staggered joints. Foil webs are used as boundary layers between individual panel layers 10 inserted. 11 denotes the masonry of the foundation.

At 12 there is an additional gas discharge nozzle with a shut-off valve in the container called rdach. Stored liquefied gas is pumped through the immersion tube 13 to an evaporator system (not shown). The maximum liquid level in the container 1 is denoted by 15. 16 is the gas collection space common to the container 1 and the annular space 5.

Suitable materials for the containers 1 and 2 are, for example, steels with 9% by weight of nickel or aluminum alloys. As an insulating material Mineral fillers or fibers in the form of bulk powder or stuffing packs are preferably suitable for the container shell and roof.

For potting and sealing the joints between the panels of the floor insulation cold tough fillers can be used. Polyethylene foils, for example, are suitable as intermediate layers between the panel layers. ,

The storage containers according to the invention are suitable for storing all liquefied gases as long as there is no particular risk of corrosion and as long as there is a need to store large quantities. The containers are particularly suitable for storage capacities of up to about 50,000 cbm per unit with diameter-height ratios of 1: 1 to 4: 1. The thickness of the insulating layer for the storage of liquid methane, for example, is between 1 and 2 _{or 3} depending on the size of the container, the required evaporation rate and the insulation system used.

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Claims (5)

PA TENT CLAIMS 1)] Multi-walled insulated container for storing liquefied Gases under normal or moderately increased pressure at temperatures significantly below the ambient temperature, characterized by the inner storage container 1, which is open at the top and made of cold-tough material, by the outer security container 2 with the spherical roof 12 surrounding it at a distance from the annular gap 6, which also are made of cold-tough material and provided with a highly insulating thermal insulation 11, and through the load-bearing insulation consisting of several layers with staggered joints of insulating panels on top of one another between the bottoms of the inner storage container 1 and the outer safety container 2. ' 2) insulating container according to claim 1, characterized in that Continuous foils are laid between the plate layers of the floor insulation. 3) insulating container according to claims 1 and 2 characterized by one or more dip tubes 7, which through the container cover are led down to a small distance above the floor in the annular space 6. 4) insulated container according to claims 1 to 3 characterized by the preferably pneumatic liquid level indicator 8 in the annular gap 6. 009831/1438 5) Procedure for commissioning the insulated container according to the ' Claims 1 to 4, characterized in that the precooling by filling in a liquefied inert gas, preferably Nitrogen in the annular gap and the storage container and evaporation of the liquefied inert gas ». ^ Until it is completely displaced the air is made, and that then the further cooling when filling the storage container with the liquefied to be stored gas takes place. 009831/1438 BATH ORIGINAL " Empty, page