DE2146135A1 - Plant for underground storage of gas - Google Patents

Description

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BD / HB / SM / 19506
LE 2.9.1971

^Di r '' - i ι I ':.: Pjimann

Munich 2. Γ: α:; _i { _a | J
Te. ". 2 6J 3 ri 89

Munich, September 15, 1971

GAZ DE FRANCE, PARIS (France)

"Plant for underground storage of grass."

The present invention is concerned with the problem of underground storage of gas and, in particular, deals with facilities for the utilization of a supply of flammable gas, which is intended for short-term temporary help or for short-term replacement and under .highem Pressure is stored in an artificial cavity, for example was created by controlled leaching of a layer of salt.

It is known that the consumption of manufactured gas and especially natural gas because of the ease of use of this fuel constantly growing. The supply of an ever increasing number of users and their periodically fluctuating needs have caused the distributors of flammable gas to oppose

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To cover delivery difficulties by building up stocks, with the help of which the consumption peaks can be covered without having to invest exaggerated amounts of money in expanding production. Because of the size of the consumption and the geographical The expansion of the distribution network includes these stocks of very large quantities of gas which can reasonably not be reached by human hands built containers, such as in the classic gasometers can be stored. For this reason it has become customary Structures that form geological spaces for the storage of combustible gas, such as exploited deposits of crude oil or natural gas, or to use water-bearing layers. Another storage method is to keep the gas in a liquefied state.

The first solution has the major disadvantage that the required geological structures are seldom in the vicinity of the Consumption centers are located and do not always meet the requirements for the tightness of the ceiling and the porosity of the bearing that forms the bearing Shift are sufficient; this not only means a certain risk of losing an expensive product must, but also makes it impossible to be able to make the necessary withdrawals quickly in order to be able to cover consumption peaks immediately. The second method not only requires the manufacture of artificial, specially elaborated containers, but also requires them successive operations for liquefaction and transfer in gaseous form, the cost of which cannot be neglected.

To remedy the above-mentioned disadvantages of the previously known Storage methods have been proposed to cover extreme consumption peaks as a new and promising technique attack, according to which the gas is stored under high pressure in cavities created by monitored leaching of salt layers develop; this technique has the major advantages that the storage of gas in cavities takes care of all the problems that the Concern the capacity and porosity of the bearing cavity; further This method enables the volume of the stored gas to be determined as desired and allows a maximum extraction rate; Because of the geographical distribution of the salt deposits, it is possible in the majority of cases to use the gas in the immediate vicinity To be stored near the consumables.

The underground storage of gas under high pressure in

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Cavities created by controlled leaching of a layer of salt are nonetheless difficult technical Problem learning. The first of these problems is how to create one Excavation, the size and shape of which corresponds to the needs, and those necessary for the underground storage of gas has mechanical strength and tightness. Is this problem correct? beyond the scope of the present invention, which is in is essentially devoted to the difficulties involved in exploiting such a previously created cavity. In the Indeed, this exploitation poses numerous difficulties, especially because satisfying the in short time intervals, for example daily consumption peaks occurring in an urban or industrial conurbation have a very large supply flammable gas required. The first of these difficulties, already mentioned, relates to the tightness of the cavity, which must be perfect in order to exclude any loss of stored gas ^ i which would be tantamount to the closure of a very large capital, regardless of the risk of accidents that the gas flight entails brings. The second problem follows from the size of the investment Means that can only become profitable after a long period of use, on the order of several decades, what necessarily a monitoring and precise maintenance of the built Equipment imposed.

The invention relates to a system for underground Storage of gas that corresponds to the technology explained and offers the greatest possible flexibility in use, and the at the same time the greatest possible guarantee in terms of safety and the lifespan, thanks to the use of suitable technical means, some of which are already known, but their Correction to the special needs of taking advantage of such Plant is sufficient.

A system corresponding to the invention for the underground storage of gas, in particular for the utilization of a supply flammable gas intended for temporary relief or replacement, stored under high pressure in an artificial cavity is, which was created for example by controlled leaching of a salt layer, isναι a shaft with a tight Expansion formed, in which channels for the gas and the saline solution are built, the said cavity with a shaft head

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connect, which is equipped in such a way that the input of to be stored .Gas under pressure and the removal of stored gas to Purposes of its distribution, the_monitoring and maintenance of the underground equipment and the excavation, and if necessary the isolation of the latter becomes possible.

The plant according to the invention is essentially thereby marked ,, that the lower end of the channel for "the saline solution is sealed by means of a plug, which under normal conditions Every change in level of the hydraulic closure Prevents saline bedas so that the alternating Compression and relaxation of the stored gas in a constant Volume take place under approximately adiabatic conditions, and the inner wall of the cemented cavity thermally against the gas through an SfcJiicht. OI or another with the gas not chemically reacting liquid is isolated, which is arranged in a concentric to said wall and to the latter at its lower Liner attached at the end by means of a sliding seal is held, while any sudden relaxation of the stored gas is prevented by an annular safety lock that is below the floor surface at the bottom of a Pipe is attached that the shaft head parallel to the lower end the narrowed to this Zwacke and moved out of the central axis

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Channel for the saline solution ^ running. penetrates, said Tube represents a hydraulic cylinder which causes the said closure to be closed in the absence of pressure.

The combination of the means just described corresponds in fact to the requirements of utilizing a storage facility of the kind discussed here, and in particular allows the thermal problems associated with the compression or the rapid Relaxation of the stored gas is related, to remedy, and In addition, the security requirements that the retention of a bring such amount of gas with it to correspond. The compression required by the determination and use of the supply and Relaxation of the gas leads to temperature differences in the order of magnitude of 100 ° (Rsius, the understandably different Cause expansions that lead to rapid destruction of the equipment with all the associated risk of accidents, unless special precautionary measures are taken. There a such an accident can never be ruled out, it is essential

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borrowed to take safety measures with those of the stock of the stored Gas can be effectively isolated; so that these measures To ensure good work in the best possible way, it is important to remove it from any external harmful influence, in particular the effects of weather conditions and the consequences of an accident that can occur at the height of the shaft head; from this G-round they are installed below ground level. The attachment, which is the subject of the invention "satisfies all of these claims.

According to another characteristic of the invention, said pipe forming the hydraulic cylinder and, if necessary, also the tube for the saline solution, extended by means of a sealed tubular lock chamber, which is provided with a contactor, the in a direct manner the introduction of the means for monitoring and maintenance in the shaft and in the cavity is permitted.

This measure allows it, without risk and without interruption of work to carry out the measures that are necessary for the proper functioning and long operating time of the plant. After a Another feature of the system according to the invention is the bed the salt solution mentioned covered by a layer of oil or another chemically neutral liquid, and so an evaporation the saline solution and the resulting influence on the stored gas are prevented.

This measure has the advantage that it is easy to monitor in the amount of the transition from saline to gas enables that the possible risk of corrosion resulting from the withdrawn gas Prevents the system and makes the cleaning of the withdrawn gas superfluous for consumption before it is delivered; extradition can be carried out in a direct manner using the pressure of the gas.

Other features and advantages of the invention will not become apparent upon reading the following detailed description of the invention exhaustive embodiment by the attached Illustrations illustrated will become even clearer.

In the attached figures, the figures la, Tb, 1_c, ■ a system corresponding to the invention by means of schematic sections which show the shaft head, the shaft and the storage cavity.

The installation for the underground storage of flammable gas, which is shown in the attached figures, essentially comprises

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Lichen a Schadtkopf shown in Figure 1a, which is connected to an underground cavity shown in Figure 1 £ by means of a shaft, the course of which can be seen in Figure 1b. The shaft has a tight, cemented extension TOy, inside which a lining 11 is concentrically arranged, the lower end of which is closed off by an annular guided / slidable seal J (FIG. 1 £). The space formed between the double wall in this way is filled by a container R (FIG. 1a) attached to the shaft head with a liquid that does not react chemically with the gas, such as water, _{oil /} nitrogen or the like and is kept in this state. In the axis of the shaft lining 10 and its lining 11 runs a channel for the salt solution 12, the cross section of which is selected to be large (FIG Saline solution from the underground cavity C_ (Figure 1c_) is challenged. The lower area 13 of the channel for d ^ e. Brine 12 is narrowed to enable its freieJi passage through the seal (FIG 1c_), and plunges into a Sal ^ solution bedded £ [, remaining on the base of the cavity G_, wherein the mouth of the channel for the saline solution of a detachable stopper 14, which is intended to prevent any rising of the salt solution, the evaporation of which is otherwise prevented by an oil layer H.

Merely with the intention of having an "idea of such a." To convey a system, some values are given below that relate to a specific system. The hollow £ that is about 100 m high, and was formed at a depth of the order of magnitude of 1500 m in the manner explained, has a volume of about 100,000m. The gas is in it. .urter a pressure that between 80 and 220 bar is variable, stored what a total amount of available gas at normal pressure of about 15,000,000m and means a possible output of 1,000,000m per day. Under Taking into account the density of the rock in question, the pressure can reach 1.7 tar per 10m depth, so that the pressure on the ground is approximately 230 bar, including a large safety margin is. The minimum pressure of 80 bar enables the extracted gas to be distributed without prior relaxation and is guaranteed

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its hydrostatic effect increases the strength of the cavity C. In order to be able to achieve the maximum output mentioned above, is the diameter of the dismantled shaft in the order of 25 cm, while that of the pipe running in the shaft for the saline solution is in the order of magnitude of 10 cm; the narrowed area this tube has a diameter of approximately three inches.

For safety reasons, the shaft head (FIG. 1a) is advantageously located on the bottom of a pit F. Approximately below the bottom of the pit F there is a closure 0 which is penetrated by the upper narrowed end section 15 of the channel for the saline solution 12, which deviates from the central axis in order to leave space for the closure, which has a movable flap 16 which can be brought to rest on a seat 17 in order to close slits 18, which are oirhete on the circumference, for the gas passage ² U. The flap 16 is closed when there is no oil pressure in a hydraulic cylinder formed by a tube 19, in which a certain pressure is normally maintained by means of a device for generating pressure P.

As shown in FIG. 1a, the tubes 19 and 19 pass through the narrowed cavity 15 of the channel for the saline solution next to one another the shaft head, outside of which they can, if necessary, be extended by tubular chambers 20, 21, with slide for the immediate passage 22,24 the introduction of tools or monitoring devices, into the shaft or into the cavity as well as the exchange of the bodies guaranteeing security »as for Example of the closure flap C) and the plug 14> enable.

The shaft head also has various contactors or slides, including a slider for the gas V Q, a contactor for the salt solution V S_, a contactor for the 01 VH and a contactor for a pressure fluid VP.

Since the various organs of the plant already mentioned are well known in drilling technology, they will not be discussed in the following described in more detail. Against this is the way of exploitation of the plant directly related to the subject invention will now be set out in detail.

Thanks to the plug 14, which closes the lower end 13 of the channel for the saline solution 12 (Figure Ic _- ), a bed filled with saline solution £ 3 to a constant level is placed on the bottom of the excavation.

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ment C, to maintain a hydraulic seal to prevent any gas leakage through the saline channel. prevented. As already explained, the evaporation of the salt solution is prevented by a layer of oil H or another chemically inactive liquid that covers the surface of the salt solution. Under these conditions, the _{gas stored in cavity C - is} alternately compressed and expanded at a constant volume, depending on whether gas is being added or removed. Because of the gas volume in question and the relatively insulating property of the salty rock G in which the cavity was formed, the compressions and relaxations take place under almost adiabatic conditions and therefore lead in a corresponding manner to heating and cooling of the gas, which can reach 100 ° Celsius . This means that all parts of the system that are in contact with the gas are subject to strong expansion, and that their

different expansions at least some parts of the equipment can destroy if no special precautions are taken.

• A first precaution is to avoid the leak-proof manhole to isolate expansion 10 from the gas by interposing a layer, ie consists of a chemically inactive liquid "and is held in the liner 11. Since the latter is in direct contact with the gas stands, while the shaft lining is protected from it, the sliding seal J at the end of the lining without damaging Effects absorb the different expansions, which can reach a few centimeters with a shaft depth of the order of magnitude from 1500m. The liner 11 and the slidably arranged Seal J therefore offer effective protection against the consequences of the temperature fluctuations of the gas for the shaft extension, which in particular has the advantage that a good tightness is guaranteed during the expected service life.

As already indicated, on the one hand it has good storage properties the cavity C! the consequence that only a minimum hydrostatic pressure has to be maintained; on the other hand it is necessary any exceptionally great relaxation of the mentioned To avoid hollowing out the gas, which lead to cooling that are incompatible with the good condition of the facility.

The system is longer to allow any strong relaxation to be dec- ^ elt ^ -rt · n

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QtwijGii to foreland , with a closure (D grouper security pass, which is more advantageous W.3 & below ground level to protect it from external influences, and which is controlled so that it is open under normal conditions and author. is iutisch closed when an error la workflow of the system occurs.

The operational reliability requirements of this Closure C) means that, with regard to the operating time of the system, the possibility of its control and self its periodic replacement must be provided for; this fact justifies the structure of the Sahachtkopf and especially the arrangement parallel to the channel for the saline solution 15 of the tube 19 and its extension by means of a tight, tubular chamber 20, which has a direct passage ge: ;; au - ': ends slide 22 is provided.

The addition of a similar chamber 21 to the channel 12 for the Sf.l ;; löi "3un, p: is explained by the need to remove the plug 14 periodically to examine or exchange, or from the obligation to Measure and adjust the height of the solution mirror can.

Of course, the invention is by no means limited to the embodiment limited, which was briefly described and only serves as an example; the invention could equally and particularly easily applied to the exploitation of underground cavities created by means other than salt leaching, will.

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Claims (3)

2U6135 P_A_T_E_N_T_A_N_8_P_R_U_C_H_E 1. System for the underground storage of G-as, in particular for the utilization of a supply of combustible G-as, which sura is a short-term replacement or for short-term relief intended to be stored under high pressure in an artificial cavity, which was created, for example, by monitored leaching of a salt layer is, a system, which is formed by a shaft ax-tight expansion, in which channels for the gas and the saline solution are built, which connect the said cavity with a shaft head, which is equipped so that the input of to be stored alternately Gas under pressure and the extraction of stored gas for the purpose of its distribution, the supervision and maintenance of the underground equipment and the excavation and, if necessary, the isolation of the latter is possible, and which is characterized in that the lower end (13) of the saline solution channel is sealed by means of a plug (14) which, under normal conditions, prevents any change in level of the salt solution bed forming a hydraulic seal, so that the alternating compression and relaxation of the stored gas take place in a constant volume under approximately adiabatic conditions, and thereby the inner wall of the cemented cavity (10) thermally against the gas by a S; hicht is isolated from 01 or some other liquid which does not react chemically with the gas, which is held in a lining 11 arranged concentrically to said wall and attached to the latter at its lower end by means of a guided sliding seal J, while each one occurs suddenly relaxation of the stored gas is prevented by an annular security seal 0, which is mounted below the floor surface P on the lower part of a tube (19) of the narrowed the well head at the lower end (15) for this purpose and gerückten from the central axis of the channel for the Saline solution running in parallel d penetrates, said pipe representing a hydraulic cylinder which causes said closure to be closed in the absence of pressure. 2. Plant according to claim 1, characterized in that the one hydraulic cylinder forming pipe (19) as well as in case of need d-iü pipe (l ^) running parallel to it for the saline solution of f! in a tube-like dense comb- (20) is lolled, the one 2098 ?? / Q500 SAO ORIGiMAL 2U6135 has the slide (22) allowing direct passage, which enables the introduction of monitoring and maintenance means into the shaft and into the cavity C_. 3. Plant according to claim 1 or claim 2, characterized in that the bed filled with the salt solution S_ of a Layer of 01 H or some other chemically neutral liquid is covered, preventing any evaporation of the saline solution in the Scooping out (D and consequently its being carried along by the removed Gas from the latter is prevented. 2098? 7/0 500 _ «AD Le r s e ite