Cryogen storage system

Abstract

The invention relates to cryogenic equipment, and more particularly to isothermal vessels intended for storing a cryogen in a liquid state. The present cryogen storage system comprises a peripherally insulated cryogenic chamber and a plurality of cryogen storage vessels disposed in said cryogenic chamber and containing a liquid cryogen and a gaseous cryogen situated above the liquid cryogen. Each of the plurality of vessels has a volume of up to 1,000 litres and is connected to a liquid cryogen reservoir for filling or emptying the vessels. The product of the total volume of the connected vessels and the unit of working pressure is not greater than 10,000. Each of the plurality of vessels is connected to the liquid cryogen reservoir for filling or emptying the vessels of a liquid cryogen. The invention makes it possible to reduce the dangerousness of storage and to simplify the processes of assembling and maintaining the storage system.

Description

[0001] Cryogenic substance storage system

[0002] AREA OF TECHNOLOGY

[0003] The invention relates to cryogenic equipment, specifically to isothermal vessels designed for storing cryogenic substances (e.g., carbon dioxide (CO2)) in a liquid state and transferring them for use in various technical fields or for use in the production of various products based on them, such as gasification in the food industry, the production of dry ice, or fire extinguishing. The invention is aimed at ensuring industrial safety and preventing accidents, incidents, and injuries at industrial facilities when using vessels operating under excess gas pressure in a liquefied state (liquefied gases under pressure), namely, under the excess pressure of liquid carbon dioxide.

[0004] LEVEL OF TECHNOLOGY

[0005] The main parameters, technical requirements and testing methods are regulated by such state documents as: Technical Regulations of the Customs Union "On the safety of equipment operating under excess pressure" (TR CU 032 / 2013) in the territory of the Customs Union, Directive 2014 / 68 / EU in the European Union, ASME Boiler and Pressure Vessel Code in the USA.

[0006] According to TP CU 032 / 2013, liquid carbon dioxide and compressed air are classified as working environments of group 2, since group 1 includes working environments consisting of flammable, oxidizing (except air with an oxygen content corresponding to the natural composition of atmospheric air), combustible, explosive, toxic and highly toxic gases, liquids and vapors in a single-phase state, as well as their mixtures.

[0007] Isothermal tanks for storing and / or transporting liquid low-temperature carbon dioxide are known, manufactured in the form of stationary storage tanks or transport tanks, with volumes of 1.25-50 m3 (GOST 19662-89. Isothermal tanks for liquid carbon dioxide):

[0008] • A tank for storing a liquid cryogenic product (SU 1139929 A1, published 15.02.1980) contains an outer casing, an inner vessel with a false shell, thermal insulation and pipes for the input and output of the cryogenic product, while the false shell is closed at the top by a bottom with openings, and the pipe for the output of the cryogenic product is located outside the false shell.

[0009] • A cryogenic vessel (SU 903657 A1, published 02 / 07 / 1982) contains a casing, an internal heat-insulated vessel with a neck and a plug, between which a channel for the vapors of the cryogenic product is made, and a lid, wherein the lid is installed at a distance from the casing and an expansion chamber is formed between the lid and the casing. • A cryogenic tank (RU 79639 U1, published 10.01.2009, prototype) for liquefied gas contains an outer metal shell, an inner metal vessel placed in it to form an interwall cavity, a heat-insulating layer between them and pipelines with shut-off and safety valves, wherein the heat-insulating layer is made in the form of vacuum-powder insulation, the inner vessel is fixed in the upper part of the outer shell on supports with heat-insulating jumpers and on stretchers in its lower part, the pipeline for removing the gas phase is connected to the upper part of the inner vessel, and the pipeline for the liquid phase is connected to its bottom part.

[0010] The above sources have a number of disadvantages:

[0011] - all of them are manufactured according to the size range specified by the manufacturer, for example, 4, 6, 8, 10, 12.5, 20, 22.5, 25, 30, 40 and 50 cubic meters, which does not allow you to start storing liquid CO2 in smaller volumes and scaling the volume in smaller increments, for example, by 0.5 cubic meters;

[0012] - one large tank has a very high load on the ground, for example, an empty tank of 10 cubic meters has its own weight of almost 5000 kg, and a filled one - almost 15000 kg, if the tank has two supports, then each one has to bear 7500 kg, which almost always requires the installation of tanks on a foundation slab outside the building, which immediately leads to the installation of a roof to protect the tank from natural precipitation;

[0013] In industrial settings, as an extreme case of an emergency, a shock wave will be generated by a vessel explosion. The extent of damage to structures, equipment, machinery, and utilities, as well as the extent of injury to people, depends on the magnitude of the excess pressure at the shock wave front (DPf). The primary hazard during operation of such vessels is the possibility of their rupture due to the sudden adiabatic expansion of gases and vapors (i.e., a physical explosion). A breach of the vessel's seal is dangerous not only for maintenance personnel but also for everyone in the hazardous area, and can lead to significant damage, fires, and mass poisoning.When vessels are depressurized, hazardous and harmful production factors are created, depending on the physicochemical properties of the working environment. This creates the risk of injury and destruction associated with high gas pressure in the system; thermal burns due to exposure to high and low temperatures; and suffocation and poisoning by inert gases. Liquid CO2 storage tanks almost always pose a high explosion hazard, as liquid CO2 expands greatly upon release, posing a threat to nearby people, buildings, and equipment. The power of the explosion is proportional to the volume and pressure in the depressurized vessel. Therefore, the smaller the vessel, the lower the explosion energy and the risk of an accident.

[0014] - a single large tank with a capacity of 4 to 20 cubic meters is a large and heavy load (2,200 to 7,300 kg, with the largest dimensions being 4,000 to 11,500 mm), requiring special trucks and vehicles for loading, transporting, and unloading the tank. Each individual 500-liter receiver weighs 150 to 200 kg, with the largest dimensions being 1,700 to 2,200 mm.

[0015] Placing large tanks outdoors requires high capital investment, and such tanks are rarely installed indoors due to the even higher hazard. Multiple tanks, each approximately 400-700 liters in size and with a pressure of 14 to 24 atm, can easily be placed in any non-residential building, as state industrial safety regulations for hazardous industrial facilities no longer apply.

[0016] Large tanks often have a pressure (MPa) times geometric volume (m3) product greater than 1.0 and therefore almost always require registration as a hazardous production facility, as governments in various countries oversee such hazardous facilities in a special manner. Servicing such tanks requires personnel certification, obtaining a license to operate, and maintaining extensive documentation. However, the operation of a vessel with a capacity of 400-700 liters and a pressure of 14 to 24 atm is not subject to government oversight, unless, of course, such receivers are already installed at existing hazardous production facilities.

[0017] DISCLOSURE OF THE INVENTION

[0018] The objective of the claimed invention is to develop a method and system for storing a cryogenic substance with a low level of storage hazard, and to provide a simplified process for installing the storage system and for maintenance.

[0019] The technical result of the invention is to reduce the level of storage hazard.

[0020] The specified technical result is achieved due to the fact that the cryogenic substance storage system contains:

[0021] - cryogenic chamber with peripheral thermal insulation;

[0022] - a plurality of vessels for storing a cryogenic substance, located in a cryogenic chamber and containing a liquid cryogenic substance and a gaseous cryogenic substance located above the liquid cryogenic substance;

[0023] - each vessel from the said set ensures storage of a cryogenic substance at an operating pressure of 10 to 32 atm, is made with a volume of up to 1000 liters, wherein the product of the quantity of volume by a unit of operating pressure does not exceed 10,000; - each vessel from the said set is connected to a collector of liquid cryogenic substance for filling or emptying the said vessels.

[0024] Cryogenic storage vessels are made of grade 09G2S steel. The thickness of the welded bottom and cylindrical welded wall of the cryogenic storage vessels ranges from 3 to 20 mm.

[0025] Cryogenic storage vessels are made of austenitic cryogenic steel using a welded process. The thickness of the welded bottom and cylindrical welded wall of the cryogenic storage vessels ranges from 3 to 20 mm.

[0026] The system is equipped with a refrigeration unit, at least one internal cooling unit of which is installed inside the cryogenic chamber.

[0027] The internal cooling units of the refrigeration unit are designed with the possibility of removal / installation through a window of the cryogenic chamber, which has a cross-section that is no more than five times larger than the cross-section of the internal cooling unit in the plane of the window.

[0028] The vessels for storing the cryogenic substance are mounted on the supports of the power frame, which pass through the bottom wall of the cryogenic chamber.

[0029] Each vessel for storing a cryogenic substance from said plurality is equipped with a shut-off valve having a closed or open position for filling or emptying said vessels, wherein a part of said plurality of vessels or one vessel from the plurality is connected to a liquid phase collector through open shut-off valves, provided that the product of the quantity of the sum of the volumes of the vessels included in said part of said plurality of vessels per unit of working pressure does not exceed 10,000.

[0030] Switching along the liquid phase manifold from the current part of the plurality of connected vessels for storing the cryogenic substance to the next part of the plurality of vessels or from the current connected vessel to the next vessel is carried out as the liquid cryogenic substance is consumed in the current part of the plurality of vessels or in the current vessel.

[0031] BRIEF DESCRIPTION OF DRAWINGS

[0032] The invention will be better understood from the description, which is not limiting in nature and is given with reference to the accompanying drawings, which show:

[0033] Fig. 1 - assembled storage system.

[0034] Fig. 2 - Assembled pneumatic-hydraulic circuit.

[0035] Fig. 3 - Simplified pneumatic-hydraulic circuit diagram in assembly.

[0036] Fig. 4 - Unit of one vessel for storing cryogenic substance in a pneumatic-hydraulic circuit.

[0037] Fig. 5 - Power frame. Fig. 6 - View of cryogenic substance storage vessels installed on the power frame.

[0038] Fig. 7 - Storage system with the internal cooling unit removed

[0039] 1 - vessel for storing cryogenic substance; 1.1 - level of liquid cryogenic substance in the vessel; 2 - thermal insulation of the cryogenic chamber; 3 and 5 - valve for input and output of liquid cryogenic substance, respectively; 4 and 6 - valve for input and output of gaseous cryogenic substance, respectively; 7.1 - internal cooling unit of the refrigeration unit; 7.2 - external unit of the refrigeration unit; 8 - pressure gauge of gaseous cryogenic substance; 9 - safety valve of gaseous cryogenic substance; 10 - collector of liquid cryogenic substance; 10.1

[0040] - manual shut-off valve; 10.2 - automatically controlled shut-off valve; 1 1 - liquid cryogenic substance hose; 12 - gaseous cryogenic substance collector; 12.1

[0041] - manual shut-off valve; 12.2 - automatically controlled shut-off valve; 13 - gaseous cryogenic substance hose; 14 - load-bearing frame; 14.1 - load-bearing frame base; 14.2 - load-bearing frame posts; 15 - control system cabinets; 16 - drain valve for draining condensate.

[0042] IMPLEMENTATION OF THE INVENTION

[0043] The cryogenic substance storage system comprises a cryogenic chamber with peripheral thermal insulation (2), a plurality of vessels (1) for storing the cryogenic substance, located in the cryogenic chamber and containing a liquid cryogenic substance and a gaseous cryogenic substance located above the liquid cryogenic substance. Moreover, each vessel (1) of said plurality ensures storage of the cryogenic substance at an operating pressure of 10 to 32 atm and is made with a volume of up to 1000 liters, wherein the product of the quantity of volume per unit of operating pressure does not exceed 10,000. In addition, each vessel (1) of said plurality is connected to a collector (10) of the liquid cryogenic substance for filling or emptying said vessels (1).

[0044] Vessels (1) for storing cryogenic substances can be made of 09G2S steel. The thickness of the welded bottom and cylindrical welded wall of the vessels (1) for storing cryogenic substances ranges from 3 to 20 mm.

[0045] Vessels (1) for storing cryogenic substances can be manufactured from austenitic cryogenic steel using a welding process. The thickness of the welded bottom and cylindrical welded wall of the vessels (1) for storing cryogenic substances ranges from 3 to 20 mm.

[0046] The system is equipped with a refrigeration unit comprising at least one external unit (7.2) and at least one internal cooling unit (7.1), installed within the cryogenic chamber. The refrigeration unit reduces or eliminates the evaporation of the liquid cryogenic substance, thereby reducing or eliminating the increase in pressure in the vessels (1) for storing the cryogenic substance to critical values.

[0047] The internal cooling units (7.1) of the refrigeration unit are designed to be removed / installed through a cryogenic chamber window, which has a cross-section no more than five times larger than the cross-section of the internal cooling unit (7.1) in the plane of the window. The cryogenic chamber window with the installed internal cooling unit (7.1) of the refrigeration unit is closed with a removable panel (2.1). The internal cooling unit (7.1) can be removed through the open window with minimal cold loss, thereby reducing cryogenic losses.

[0048] The refrigeration unit performs two functions:

[0049] - compensation of heat flows entering the chamber through thermal insulation and metal “thermal bridges” from the external environment;

[0050] - condensation of gaseous cryogenic substance to reduce the pressure in vessels to the required level;

[0051] Condensation of a gaseous cryogenic substance is carried out in several ways:

[0052] - transfer of cold through the walls (shell and top bottom) of the vessels to the gaseous cryogenic substance;

[0053] - transfer of cold through the walls (shell and upper bottom) of the vessels to the liquid cryogenic substance, and then through the liquid cryogenic substance to the gaseous cryogenic substance;

[0054] - transfer of cold through a separate heat exchanger to a gaseous cryogenic substance, which is located above the vessels for draining the condensed cryogenic substance into the vessels, following the example of a condenser in standard long-term storage tanks for liquid CO2 (LDS).

[0055] The vessels (1) for storing the cryogenic substance are mounted on the posts (14.2) of the load-bearing frame (14), which pass through the lower wall of the cryogenic chamber. For more convenient installation of the system, the load-bearing frame on the posts (14.2) of the load-bearing frame (14) supports the weight of the said vessels (1), the risk of tipping over the said vessels (1), and the denting of the thermal insulation from the weight of the said vessels (1).

[0056] Each vessel (1) for storing a cryogenic substance from the said plurality is equipped with a shut-off valve (12.1, 12.2) having a closed or open position for filling or emptying the said vessels (1).

[0057] In this case, part of the mentioned plurality of vessels (1) or one vessel (1) from the plurality is connected to the liquid phase collector (10) through open shut-off valves (12.1, 12.2) provided that the product of the quantity of the sum of the volumes of the vessels (1) included in the mentioned part of the mentioned plurality of vessels (1) by the unit of working pressure does not exceed 10,000. Switching along the liquid phase collector (10) from the current part of the plurality of connected vessels (1) for storing the cryogenic substance to the next part of the plurality of vessels (1) or from the current connected vessel (1) to the next vessel (1) is carried out as the liquid cryogenic substance is consumed in the current part of the plurality of vessels (1) or in the current vessel (1).

[0058] The system can be in the following states:

[0059] • “Empty system”: when all vessels are empty and not under pressure; this condition is typical when assembling a system before commissioning or during maintenance;

[0060] • “Empty system”: when there is no liquid cryogenic substance in the vessels, but the vessels are under pressure of gaseous cryogenic substance;

[0061] • “Filled system”: when liquid cryogenic substance is present in the vessels and the vessels are under the pressure of the liquid cryogenic substance;

[0062] • “System filling”: when liquid cryogenic substance is supplied to the vessels from an external source of liquid cryogenic substance and the vessels are under the pressure of liquid cryogenic substance;

[0063] • “System emptying”: when liquid cryogenic substance leaves the vessels to carry out some process (production of dry ice, carbonation of drinks, etc.) and at the same time the vessels are under the pressure of liquid cryogenic substance.

[0064] When filling a system of multiple vessels (1) for storing a cryogenic substance, the following number of vessels can be simultaneously connected (by opening shut-off valves 10.1, 10.2, 12.1, 12.2) to the liquid (10) and gaseous (12) cryogenic substance collectors through the liquid (11) and gaseous (13) cryogenic substance hoses, if the condition below is met. The best options for the system operation during its filling (number of connected vessels): each specified vessel (1) has a maximum safe volume at a given storage pressure of the liquid cryogenic substance and operates in turn, namely with a pressure from 10 to 32 atm with a volume of up to 1000 liters, optimally with a pressure from 15 to 25 atm with a volume of up to 800 liters; The best options are those with a pressure of 17 to 20 atm with a volume of up to 600 liters, where the product of the volume (sum of volume) per unit of working pressure does not exceed 10,000. This achieves the lowest metal consumption of the system, and is carried out as follows.

[0065] The gaseous cryogenic substance formed during the storage process by evaporation of the liquid cryogenic substance in the vessels (1) for storing the cryogenic substance is removed from the said vessels (1) in the following manner: discharge into the atmosphere through the collector (10) of the gaseous cryogenic substance;

[0066] • discharge into the atmosphere through the drain valve (16) on each specified vessel (1);

[0067] • discharge into the atmosphere through the safety valve (9) with which each specified vessel (1) is equipped;

[0068] • return of gaseous cryogenic substance from the specified vessels (1) using hose (13) of gaseous cryogenic substance and collector (10) of gaseous cryogenic substance into the upper cavity of the source with liquid cryogenic substance. This method of removing gaseous cryogenic substance is more expedient, since there is no loss of gaseous cryogenic substance.

[0069] When emptying the system, the order of operation of the vessels (1) for storing the cryogenic substance when emptying the system is observed, namely: simultaneously, for emptying the system, it is possible to connect (when opening the shut-off valves (10.1, 10.2, 12.1, 12.2)) to the collectors of liquid (10) and gaseous (12) cryogenic substance through the hoses of liquid (11) and gaseous (13) cryogenic substance such a number of vessels, if the condition below is met. At any given time, one specified vessel (1) or a group of specified vessels (1) with a pressure of 10 to 32 atm with a total volume of up to 1000 liters is supplied to the manifold; the best option is when only one receiver is connected with a pressure of 17 to 20 atm with a volume of up to 600 liters, and the product of the quantity of volume or the sum of the volumes per unit of working pressure does not exceed 10,000.In this way, maximum safety of the system is achieved in the event of depressurization of any of the receivers, since depressurization of the other indicated vessels (1), which are closed by shut-off valves (10.1, 10.2, 12.1, 12.2), will not occur through the collectors (10, 12).

[0070] Examples of various options for the number of vessels (1) simultaneously connected to the collector of liquid cryogenic substance for storing cryogenic substance based on the pressure and the total volume of liquid cryogenic substance in them are as follows:

[0071] • The pressure in the vessel is 10 atm, the volume of the vessel is 999 liters, the number of vessels simultaneously connected to the collector of liquid cryogenic substance (1) cannot be more than 1 (1*10*999<10,000).

[0072] • The pressure in the vessel is 10 atm, the volume of the vessel is 499 liters, the number of vessels simultaneously connected to the liquid cryogenic substance collector (1) cannot be more than 2 (2*10*499<10,000).

[0073] • The pressure in the vessel is 10 atm, the volume of the vessel is 199 liters, the number of vessels simultaneously connected to the collector of liquid cryogenic substance (1) cannot be more than 5 (5*10*199<10,000). The operation of the declared system using liquid CO2 as an example, taking into account the best option for the system’s operation, is carried out as follows.

[0074] Filling of the declared system: after commissioning of the "empty system", a source of cryogenic substance (liquid CO2) is connected to the valve (4), for example, in the form of a gate valve, the collector (10) of liquid CO2 of the "empty" system, in which the vessels (1) for storing the cryogenic substance are under a pressure of 18 atm. The source of cryogenic substance (liquid CO2) is a mobile tank with liquid cryogenic substance and gaseous cryogenic substance, located above the liquid cryogenic substance. The upper point of the mobile tank is connected via a flexible hose to the collector (12) of gaseous cryogenic substance, and the lower point of the mobile tank is connected via a flexible hose and a circulation pump to the collector (10) of liquid cryogenic substance. Due to the circulation pump, the liquid cryogenic substance flows under pressure into the vessels (1) of the cryogenic substance, and the contained gaseous cryogenic substance from the said vessels (1) flows into the mobile tank.Another stationary or mobile cryogenic storage vessel, which also contains a gaseous liquid cryogenic substance (gaseous CO2) above the liquid, may serve as a storage source for the cryogenic substance. To meet the above requirement (the product of the volume and the unit of operating pressure does not exceed 10,000; this number will allow us to determine the maximum number of cryogenic storage vessels (1) that can be filled at a given time in a filled system), given that the system contains multiple cryogenic storage vessels (1) with a volume of 499 liters and a pressure of 18 atm is created in the vessels, no more than 1 cryogenic storage vessel (1) can be filled during system filling.

[0075] Based on the above-described condition, when filling / emptying the system for filling each of the vessels (1) for storing a cryogenic substance with a volume of 499 l, located at a pressure of 18 atm, the shut-off valves (10.1, 10.2) are opened, the valve (4) of one of the said vessels (1) and liquid CO2 through the collector (10) of the liquid cryogenic substance and the hoses (11) of the liquid cryogenic substance by means of a gear or centrifugal pump enters the first vessel (1) for storing the cryogenic substance.

[0076] As soon as the level (1.1) of liquid CO2 in the first vessel (1) rises to the required volume, the shut-off valves (10.1, 10.2) of the first said vessel (1) are closed, and the shut-off valves (10.1, 10.2) of the second vessel (1) from the said plurality are opened, as a result of which the second vessel (1) is filled to the required level (1.1). As the vessels (1) are filled, the shut-off valves (10.1, 10.2) for the filled vessels (1) are closed in turn, and the shut-off valves (10.1, 10.2) for the empty vessels (1) are opened. After filling all the vessels (1) for storing the liquid cryogenic substance, the claimed system goes into the "Filled system" state, as a result of which the liquid "cryogenic substance" is stored.

[0077] During storage, liquid CO2 evaporates, resulting in the formation of gaseous CO2 above the liquid CO2, leading to an increase in pressure in each of the vessels (1) for storing the cryogenic substance, which may lead to an emergency situation if the critical pressure value in each of the vessels (1) is exceeded. To prevent an emergency situation when the critical pressure in the specified vessels (1) is reached, the safety valves (9) installed on each receiver are activated. Shut-off valves (12.1, 10.1) are used to manually disconnect the receiver from the system in case of maintenance or repair. The drain valve (16) is used to drain condensate that may form in the pipe where the pressure gauge (8) and safety valve (9) are installed.

[0078] The main shut-off valves (10.2, 12.2) are most often controlled automatically by electromagnetic coils or pneumatic actuators, which are controlled by the control system cabinet. For convenient replacement or repair of the main shut-off valves (10.2, 12.2), which will constantly open / close during system operation, it is recommended to install backup valves (10.1, 12.1) to shut off the receiver for maintenance of the main shut-off valves (10.2, 12.2). Automatic control can be implemented using a microcontroller, which is capable of determining the fill level of each receiver or the mass of liquid CO2 both during filling and during emptying (dispensing liquid CO2). The fill level can be determined, for example, by float sensors, differential pressure gauges, liquid level pressure transducers, weighing transducers, etc.

[0079] Use of the claimed system: Most often, the claimed system is used to dispense liquid CO2 through a liquid (10) cryogenic substance manifold, through which filling also occurs. A beverage carbonation device, for example, is connected to tap (5). Based on the above-described condition, when emptying a system with 10 vessels (1) filled with liquid CO2 for storing cryogenic substance with a volume of 999 liters and under a pressure of 10 atm, only one vessel (1) is emptied first. To do this, shut-off valves (10.1, 10.2) are opened, tap (5) is opened, and liquid CO2 enters the beverage carbonation device. As soon as the level (1.1) of liquid CO2 in the first emptying vessel (1) decreases to the required level of liquid CO2 (complete or partial emptying), the shut-off valves (10.1, 10.2) for this vessel are closed and the shut-off valves (10.1, 10.2) for the second vessel (1) from the specified set are opened.As the vessels (1) are emptied, the shut-off valves (10.1, 10.2) for each vessel are closed and opened in turn.

[0080] An example of the sequential operation of the vessels (1) during their emptying is shown in Fig. 3, where four receivers are shown (from left to right): • the first two vessels (1) for storing the cryogenic substance are emptied, their level (1.1) of liquid cryogenic substance is very low, the shut-off valves (10.1, 10.2) on them are closed;

[0081] • the third vessel (1) for storing cryogenic substances during the emptying process, its shut-off valves (10.1, 10.2) are open;

[0082] • the fourth vessel (1) for storing the cryogenic substance is still full, waiting its turn to be emptied, its shut-off valves (10.1, 10.2) are closed.

[0083] Vessels (1) for storing cryogenic substances are made of steel suitable for storing liquid cryogenic substances. The storage temperature of liquid cryogenic substances is usually from -30°C to -20°C, but other temperatures are also possible. There are situations when the valves for releasing the gas phase are accidentally or intentionally opened and held until the pressure in the vessel is established close to atmospheric. As a result, liquid CO2 transforms into a gaseous and solid state, the latter of which is often called dry ice. Dry ice at 1 atm has a temperature close to -80°C. Such dry ice remains in the vessel and is capable of cooling the bottom and welds of the vessel to its own temperature. When using standard air vessels (1) for storing cryogenic substances, which are generally suitable for group 2 environments according to TR CU 032 / 2013, which includes CO2, such vessels (1) can theoretically be used to store liquid CO2.However, their temperature range is within its specified limits. For example, receivers made of StZ steel have a temperature range of "minimum permissible vessel wall temperature under design pressure, -20°C." However, if dry ice forms, the bottom and welded joints will become overcooled, and immediate re-pressurization will result in weld failure due to low-temperature embrittlement.

[0084] Therefore, vessels (1) for storing cryogenic substances must be made of steel suitable for use at temperatures as close as possible to the temperature of dry ice. Such steels include, for example, the popular grade 12Kh18N10T (AISI304) or 09G2S, or other suitable equivalents approved by GOST R 52630-2012.

[0085] Steel 09G2S - Low-alloy structural steel for welded structures. Steel grade 09G2S is widely used in the production of pipes and other rolled metal products. The designation 09G2S signifies a carbon content of 0.09%, as 09 comes before the letters, followed by the letter "G," which stands for manganese, and the number 2 indicates a manganese content of up to 2%. Next comes the letter "C," which stands for silicon, but since there is no number after C, this means the silicon content is less than 1%. Thus, the decoding of 09G2S means that this steel contains 0.09% carbon, up to 2% manganese, and less than 1% silicon. Since the total amount of additives fluctuates around 2.5%, it is a low-alloy steel. There is more than one equivalent to 09G2S steel in Russia; experts consider the following grades to be identical: 09G2, 09G2T, 09G2DT. The alloy also has substitutes in other countries: 9SiMn16 (Romanian), 09G2S (Bulgarian), 9MnSi5 (German), VH2 (Hungarian), 12mn (Chinese), SB49 (Japanese).

[0086] 12Kh18N10T is a high-quality chromium-nickel steel alloy. It contains a high proportion of chromium (17-19%) and nickel (9-11%). Titanium stabilization (up to 0.8%) prevents intercrystalline corrosion.

[0087] Austenitic cryogenic steels are divided into three groups.

[0088] Chromium-nickel austenitic steels 12Kh18N10T and 08Kh18N10T. These steels are widely used. They are used to manufacture large, high-power gas distribution systems for producing liquefied gases (O2, N2, H2, etc.), transport tanks, and liquefied gas storage facilities. They weld well and have a large ductility reserve at cryogenic temperatures. The high ductility of 12Kh18N10T steel allows it to be used after cold plastic deformation to increase strength. The austenite of chromium-nickel steels is unstable, and under the influence of plastic deformation, partial martensitic transformation is possible.

[0089] Complex-alloyed austenitic high-strength steels 07X21 G7AN5 and 03X20N16AG6. These steels are used for stamped and welded products and thick-walled large-sized containers.

[0090] Austenitic chromium-manganese steels 10Kh14G14N4T and 03Kh13AG19 as substitutes for more expensive chromium-nickel austenitic steels. It should be noted that plastic deformation of chromium-manganese steels can cause partial martensitic transformation, which reduces resistance to brittle fracture. These steels are recommended for the manufacture of welded structures operating at temperatures from 20 to -196 °C (steel 03Kh13AG19) and -253 °G (steel 10Kh14G14N4T). Austenitic steels are used after water quenching at 1000-1050 °C. At normal temperatures, the yield strength of austenitic steels does not exceed 400-450 MPa.

[0091] Each cryogenic storage vessel (1) is welded and consists of two bottoms 3-20 mm thick, preferably 4-10 mm thick, and a wall 3-20 mm thick, preferably 4 to 10 mm thick. The bottom may be flat or elliptical. The material for the bottom and wall is best made of 09G2S or a similar chemical composition.

[0092] Each vessel (1) for storing cryogenic substances has at least two shut-off valves: one for the gas phase and one for the liquid CO2 phase. The first is located in the upper elliptical bottom, and the second in the lower elliptical bottom.

[0093] FNP ORPD indicates that the following equipment under pressure is not subject to registration with the bodies of Rostekhnadzor and other federal executive bodies authorized in the field of industrial safety: vessels operating with a medium of group 2 (according to TR CU 032 / 2013) at the above-mentioned temperature, for which the product of the values ​​of the working pressure (MPa) and the capacity (m3) does not exceed 1.0.

[0094] In the European Union, for example, such containers are considered to be in the category of SEP “Sound Engineering Practice” (“Good Engineering Practice”),

[0095] For government regulation purposes, when determining the capacity of a vessel, the total sum of a group of vessels is usually not taken into account if they do not operate together.

[0096] If the refrigeration unit stops operating or the refrigeration chamber is breached, heat from the surrounding environment flows to the cryogenic storage vessels (1), heating them. The liquid cryogenic substance then begins to boil, transforming from a liquid to a gaseous state. The pressure in these vessels (1) rises and, upon reaching the operating pressure of the safety valves, is released through them into the surrounding environment. For increased safety, each vessel (1) is equipped with a safety valve (9), a pressure gauge (8) for the gaseous cryogenic substance, and a drain cock (16) for draining condensate in the tube housing the safety valve (9) and pressure gauge (8). Additional safety valves can also be installed on the manifold (12). It is best to use spring-loaded safety valves with manual forced opening.

[0097] It is better to install pressure gauges and safety valves at human eye level.

[0098] Pressure relief can also occur if the source of liquid cryogenic fluid being charged has a pressure higher than the opening pressure of the system's relief valves (9). This will cause simultaneous charging and boiling of the liquid cryogenic fluid until the pressure in the source drops below the opening pressure of the relief valves.

[0099] The claimed system also provides for the storage of other known cryogenic substances and their transfer for use in various fields of technology or for use in the production of various products based on them.

[0100] To achieve this result, the volume of stored liquid cryogenic substance is divided into smaller volumes, due to the small volume of cryogenic substance storage vessels, which pose less of a hazard.

[0101] Also, to achieve the specified result, small volumes of vessels for storing cryogenic substance with liquid cryogenic substance are separated by shut-off valves and connected to a manifold for dispensing or filling liquid cryogenic substance alternately and in small volumes.

[0102] Also, to achieve the specified result, small volumes of vessels for storing cryogenic substances are placed in a sealed cryogenic chamber with sufficiently thick thermal insulation to maintain the temperature, and therefore the pressure of the liquid cryogenic substance, within the limits of values ​​​​that are safe for the operation of the vessels.

[0103] Also, to achieve this result, the sealed cryogenic chamber has a window size for removing the internal cooling unit that is close to the size of the internal cooling unit, in order to reduce the amount of heat that can enter the refrigeration chamber when removing the internal unit for maintenance, repair, or replacement.

[0104] Also, to achieve the specified result, the cryogenic storage vessels are placed on the supports of a load-bearing frame, which transfers the weight of the said vessels and the liquid cryogenic substance stored in them to the floor or foundation, bypassing the thermal insulation.

[0105] The invention has been disclosed above with reference to a specific embodiment. Other embodiments of the invention may be apparent to those skilled in the art without altering its essence as disclosed herein. Accordingly, the invention should be considered limited in scope only by the following claims.

Claims

CLAUSES OF THE INVENTION 1. A cryogenic substance storage system comprising: - cryogenic chamber with peripheral thermal insulation; - a plurality of vessels for storing a cryogenic substance, located in a cryogenic chamber and containing a liquid cryogenic substance and a gaseous cryogenic substance located above the liquid cryogenic substance; - each vessel from the mentioned set, providing storage of a cryogenic substance at an operating pressure from 10 to 32 atm, is made with a volume of up to 1000 liters, and the product of the quantity of volume per unit of operating pressure does not exceed 10,000; - each vessel from said plurality is connected to a collector of liquid cryogenic substance for filling or emptying said vessels with liquid cryogenic substance.

2. The system according to paragraph 1, characterized in that the vessels for storing the cryogenic substance are made of 09G2S steel by welding.

3. The system according to paragraph 2, characterized in that the thickness of the welded bottom and the cylindrical welded wall of the vessels for storing cryogenic substances is from 3 to 20 mm.

4. The system according to paragraph 1, characterized in that the vessels for storing the cryogenic substance are made of austenitic cryogenic steel by welding.

5. The system according to paragraph 4, characterized in that the thickness of the welded bottom and the cylindrical welded wall of the vessels for storing the cryogenic substance is from 3 to 20 mm.

6. The system according to paragraph 1, characterized in that it is equipped with a refrigeration unit, at least one internal cooling unit of which is installed inside the cryogenic chamber.

7. The system according to claim 6, characterized in that the internal cooling units of the refrigeration unit are designed with the possibility of removal / installation through a window of the cryogenic chamber, having a cross-section that is no more than five times larger than the cross-section of the internal cooling unit in the plane of the window.

8. The system according to claim 1, characterized in that the vessels for storing the cryogenic substance are installed on the supports of the power frame, which pass through the lower wall of the cryogenic chamber.

9. The system according to claim 1, characterized in that each vessel for storing a cryogenic substance from said plurality is equipped with a shut-off valve having a closed or open position for filling or emptying said vessels, wherein part of said plurality of vessels or one vessel from the plurality is connected to the liquid phase collector through open shut-off valves, provided that the product of the quantity of the sum of the volumes of the vessels included in the said part of the said set of vessels, per unit of working pressure does not exceed 10,000.

10. The system according to claim 9, characterized in that switching along the liquid phase manifold from the current part of the plurality of connected vessels for storing the cryogenic substance to the next part of the plurality of vessels or from the current connected vessel to the next vessel is carried out as the liquid cryogenic substance is consumed in the current part of the plurality of vessels or in the current vessel.

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