WO2012125055A1 - System for producing an atmosphere with a reduced oxygen content in rooms - Google Patents

Abstract

The invention relates to the gas separation field, and more specifically - to the technology for producing hypoxic gaseous mixtures for subsequent feeding into sealed rooms and containers. The system comprises a nitrogen generator on the basis of hollow gas-distributing fibres or an asymmetric membrane and a receiver 3, which generator is intended for forming a stock of highly concentrated nitrogen necessary for extinguishing fire when objects stored in a room catch fire. The room is equipped with an air conditioner 4, a system for measuring all of the parameters of the gaseous medium and with sluice doors 6. An assembly 9 which is collected into a package and comprises flat hollow membrane cells 10 located in a section of a pipe 11 is arranged outside the room. Between the membrane cells there are hollow spacer liners 12, owing to which the entire volume of the cell assembly 9 is divided into an atmospheric pressure cavity and a vacuum cavity. A vacuum pump 13 is provided for producing a vacuum in the internal cavity of the membrane cells. The pipelines are equipped with regulating valves 14, 15, 16, 17, 18 and 19. The vacuum cavity of the assembly of membrane cells 9 is connected by a pipeline 20 to the vacuum pump 13. An intercell cavity (atmospheric pressure cavity) is connected at one end via a valve 14 to an internal room volume and at the other end to the atmosphere. The claimed invention makes it possible to prevent atmospheric air from penetrating the room in the event of an oscillation in the atmospheric pressure value, even if the room is inadequately sealed.

Description

 COMPLEX FOR CREATION IN ROOMS OF ATMOSPHERES WITH REDUCED

 OXYGEN CONTENT

The field of technology. The invention relates to the field of gas separation, and more particularly to a technology for producing hypoxic gas mixtures (ie, with a low oxygen content and high nitrogen concentration) for their subsequent supply to closed rooms and containers. Hypoxic gas mixtures are used in the most diverse fields of human activity, including: to reduce the fire and explosion hazard of various objects (with a decrease in oxygen concentration in the air to 15-12%, the probability of ignition of combustible substances decreases by 5- 10 times, which effectively solves the problem of ensuring fire and explosion safety, for example, when storing petroleum products in containers); to solve the problem of increasing the preservation of various objects during their storage by reducing the rate of oxidation of materials (for example, when storing a stock of books of historical value, paintings, various devices whose materials are prone to corrosion, etc. .); for therapeutic and sporting purposes (for example, by means of hypoxic therapy in the treatment of a number of diseases of people and animals or by training athletes or sports animals in a hypoxic environment, which significantly increases the physical capacity of the body and ensures high sports results ) In addition, hypoxic mixtures with a high nitrogen content at an oxygen concentration of less than 2% can be effectively used to extinguish a fire that has already arisen by quickly throwing it into the fire. Such mixtures can be pre-stored in a special receiver.

REPLACE ITS SHEET RULE 26 The prior art. There is a known technical complex for creating and maintaining an atmosphere with a low oxygen content in closed rooms, designed to supply a hypoxic mixture into the internal volume of a room in order to prevent and extinguish a fire inside it, presented in US Patents 5,799,652 of March 30, 1999, jN 5924419 from 07.20.1999 and From 5887439 from 01.09.1999.

 The specified complex includes a nitrogen source - a nitrogen generator, which supplies nitrogen to rooms equipped with air conditioning, lock doors, devices to maintain a certain humidity and temperature, as well as a fixed oxygen concentration in the room air. All parameters are monitored, adjusted and maintained by an appropriate control system. An exhaust pipe is provided in the room to release a hypoxic mixture into the outdoor atmosphere. The well-known nitrogen generator works on the principle of short-cycle adsorption, based on different sorption activity of the sorbent with respect to oxygen and nitrogen. After certain short periods of time, in two adsorbers alternately working, there is an increase and then a decrease in air pressure, due to which it is divided into nitrogen and oxygen. Oxygen flow is discharged into the atmosphere, and nitrogen flows into the room. Gas separation occurs in one cycle by quickly switching valves within 40-90 seconds. The cycles are repeated in sequence. The disadvantages of this invention are:

 - low valve service life due to their frequent switching; - the need for periodic regeneration of the sorbent;

 - high requirements for tightness of the premises.

SUBSTITUTE SHEET (RULE 26) The most difficult to solve the technical problem in the third of these shortcomings is to provide the necessary tightness of the room.

 External atmospheric pressure cannot remain unchanged and varies, as a rule, in the range of 780-730 mm Hg. Art. With a decrease in atmospheric pressure, part of the nitrogen mixture from the room seeps through the pores, the micro-slots of the room and goes outside. The composition of the gas mixture in the room does not change, but the nitrogen consumption increases. In the case, when the atmospheric pressure exceeds the pressure of the hypoxic mixture in the room, atmospheric air enters this room through leaks in the structure and its materials and increases the oxygen concentration in the hypoxic environment, which is unacceptable. The solution to the technical problem of eliminating this problem seems rather complicated. It is impossible to ensure absolute sealing of the room, and besides, achieving a high level of sealing is a laborious and expensive process.

 The closest analogue of the present invention (prototype) is a technical complex for creating and maintaining in a closed room atmosphere with a low oxygen content according to US patent N ° 6314754 of 11/13/2001. In this technical solution, a nitrogen generator is used to form a hypoxic mixture, based on the use of selective permeability of air components - oxygen and nitrogen - through the walls of hollow polymer fibers. The specified complex includes a nitrogen generator with an inlet pipe located outdoors, a pipeline for supplying a hypoxic mixture to the internal volume of the room, an air conditioning system for the gas mixture in the room with temperature and composition control by components, lock rooms with hermetic doors and management system.

SUBSTITUTE SHEET (RULE 26) To carry out the gas separation process, the compressor compresses the outside air and delivers it into the hollow fibers of the nitrogen generator. Oxygen, seeping through the walls of the fibers into the interfiber space, enters the external atmosphere, and nitrogen is concentrated inside the fibers, which from the fibers enters the internal volume of the room intended to create and maintain a hypoxic atmosphere. From the opposite wall of the room air is discharged from the internal volume through the discharge pipe equipped with a water lock. The room is equipped with monitoring and measuring instruments and devices to maintain a certain humidity, temperature and a given oxygen concentration in the room. Regulation and maintenance of the set parameters of the indoor atmosphere of the room is carried out by the corresponding control system.

 The disadvantages of the prototype are:

 - a long period of time to create a gas mixture in the room with a certain amount of oxygen concentration;

 - great complexity and, accordingly, capital costs for sealing the room;

 - frequent switching on of the nitrogen generator to ensure the necessary oxygen concentration due to insufficient sealing of the room, which leads to an increase in energy consumption and a decrease in resource.

 Disclosure of the invention. The present invention completely solves the technical problems of eliminating the above disadvantages of the prototype. One of the main technical tasks is to prevent the penetration of atmospheric air into the room when the value of atmospheric pressure fluctuates even with insufficient tightness of the room.

SUBSTITUTE SHEET (RULE 26) The solution to this problem is achieved by the fact that in the wall of the room opposite the wall outside which the nitrogen generator is located, a pipe section is mounted that connects the internal volume of the room with the external atmosphere and is equipped with a set of flat hollow membrane cells with spacing hollow spacers assembled in a package - by oxygen selective cassettes between them, which are in turn connected to the vacuum pump through the internal cavity of the set, and to the room along the intercellular space. In this case, the optimal gap between the flat cells is from 1 to 3 mm, and the total free passage area of the pipe section is at least 300 cm.

Due to the presence of a pipe segment with a set of flat hollow membrane cells connected to a vacuum pump, when atmospheric pressure increases, the outside air will spontaneously enter the room through the gaps of the membrane cells and will automatically be enriched with nitrogen, and oxygen will be pumped out through the set of membranes. ny cells a vacuum pump. Therefore, outside atmospheric air cannot enter the room through a set of membrane cells. In addition, since air moves along the line of least resistance, it will pass, first of all, through a wide pipe, and not through small cracks in the walls. To ensure this effect, the total cross section of the pipe segment must be at least 300 cm.

Thus, the proposed technical solution allows to reduce capital costs associated with costly sealing of the room, as well as reduce energy consumption and extend the life of the nitrogen generator due to the operation of the latter for a shorter time. Consequently, both capital and energy costs are reduced.

 The second technical problem is to reduce the time it takes to create a hypoxic mixture in a room. It is solved by ensuring

SUBSTITUTE SHEET (RULE 26) circulation of the hypoxic mixture in the process of its creation in the room. To do this, a pipe connecting the internal volume of the room with the inlet pipe of the nitrogen generator is built into the wall of the room opposite the wall outside which the nitrogen generator is located.

 Thus, a mixture with a nitrogen concentration higher than in air begins to enter the compressor inlet, which speeds up the process of creating a hypoxic mixture in a room by 1.5–2 times.

The third technical task is to remove harmful substances (sulfur dioxide - S0 ₂ , hydrogen sulfide - H ₂ S, ammonia - NH ₃ ) from the room air. This is especially important when storing paintings and stock of ancient books. Harmful impurities, accumulating in a hypoxic mixture, can interact with the components of paint and paper, which can cause darkening of paintings or destruction of paper. To solve this problem, the nitrogen generator is equipped with an additional membrane section, selective for harmful impurities, located between the inlet of the nitrogen generator and the outlet of the pipeline connecting the internal volume of the room and the inlet pipe of the nitrogen generator. During the circulation of the gas mixture, harmful substances are removed and discharged into the outside atmosphere. Instead of an additional membrane section, flat cells can be placed directly in the nitrogen generator on the basis of a flat gas-permeable membrane, selective for oxygen, sulfur dioxide, hydrogen sulfide, ammonia.

 Brief description of the drawing. In FIG. 1 shows a schematic diagram of a complex for creating and maintaining a hypoxic atmosphere in enclosed spaces.

 The best embodiment of the invention. In FIG. 1 shows a schematic diagram of a complex designed to create and maintain a hypoxic atmosphere in room 1, which includes a nitrogen generator 2 based on hollow gas separation fibers or flat

SUBSTITUTE SHEET (RULE 26) asymmetric membrane and receiver 3, designed to build up a stock of highly concentrated nitrogen, which is necessary to extinguish a fire when objects stored indoors are ignited. The room is equipped with air conditioning 4, which maintains a certain temperature, a system for measuring all parameters of the gas medium and temperature 5, and lock doors 6, which exclude atmospheric air entering the room. This eliminates the change in the set parameters for the composition of the gas mixture and temperature.

To remove harmful impurities (sulfur dioxide - S0 ₂ , hydrogen sulfide - H ₂ S, ammonia - NH ₃ ), an additional membrane section 7 was used based on gas separation membranes that are highly selective for the above mentioned impurities.

 To create a pressure differential on the membranes of the nitrogen generator 2 and the additional membrane section 7, a screw type compressor 8 is installed at the inlet of the additional membrane section.

 The set 9 assembled in a package is located outside the room, including flat hollow membrane cells 10 located in the pipe 1 segment 1. Between the membrane cells there are hollow spacers 12, due to which the entire volume of the set of cells 9 is divided into atmospheric pressure bands and vacuum. To create a vacuum in the inner cavity of the membrane cells provides a vacuum pump 13. The pipelines are equipped with control valves 14, 15, 16, 17, 18, 19.

 The vacuum cavity of the set of membrane cells 9 is connected by a conduit 20 to a vacuum pump 13. An intercellular cavity (atmospheric pressure cavity) is connected on one side through valve 14 to the internal volume of the room, and the other to the atmosphere.

 Using the pipe 21, the internal volume of the premises communicates with the suction pipe of the compressor 8, and the air outlet from

SUBSTITUTE SHEET (RULE 26) premises (through the valve 15) is located opposite the nitrogen input from the nitrogen generator 2 (through the valve 15).

 The complex includes a system 22 of measuring and controlling the parameters of creation, and maintaining certain values of the gas composition, temperature and humidity in the room.

 The complex operates as follows. When the control system 22 is switched on, at its command, the fans 19, 18, 15 are partially opened and the valve 14 is completely opened. Then the compressor 8 starts working. Under the influence of the pressure difference created by the compressor 8 in the nitrogen generator 2 and in the membrane section 7 , due to the selective permeability of the membrane of the nitrogen generator, oxygen, which predominantly penetrates through the membrane, is discharged into the external atmosphere, and a gas mixture enriched with nitrogen is formed above the membrane. Nitrogen through valve 18 enters room 1, mixes with air and exits through valve 15 into pipeline 21 and enters the suction pipe of compressor 8.

 Simultaneously with the release of oxygen from the nitrogen generator 2 and the additional membrane section 7, a new portion of air enters the compressor through an open pipe into the atmosphere through valve 19.

 Thus, air enriched with nitrogen from the room to the next gas separation stage is circulated. Due to this, the nitrogen concentration in the gas mixture in the room begins to increase rapidly. This is because each time air, previously enriched with nitrogen, enters the membrane section 7 and the nitrogen generator 2, so the time for creating a nitrogen atmosphere in the room is reduced by a factor of 1.5–2.

 At the same time, harmful substances are discharged into the atmosphere through the membrane of the membrane section 7 due to its selective permeability

SUBSTITUTE SHEET (RULE 26) (sulfur dioxide - S0 ₂ , hydrogen sulfide - H ₂ S, ammonia - NH ₃ ). When the specified nitrogen concentration is reached in the gas environment of the room, the control system 22 turns off the compressor 8 and closes the valves 19, 18 and 15.

 After creating the gas medium, the control system 22 opens the valve 16 and turns on the vacuum pump 13. By creating a pressure differential over the membranes of the cells 10 in the set of membrane cells 9, the air entering it is enriched with nitrogen, and the air enriched with oxygen leaves through the vacuum pump 13 into the atmosphere.

 If the atmospheric pressure is lower than in room 1, then the gaseous medium enters the atmosphere through a set of membrane cells 9. If the atmospheric pressure is higher than the pressure in room 1, then the atmospheric air passing through the set of membrane cells 9 is enriched with nitrogen and enters the room 1. Thus, the set of membrane cells 9 performs the function of a nitrogen shutter, preventing atmospheric air from entering the room 1.

 Given that the gaps between the membrane cells 10 are from 1 to 3 mm, and the total free passage area of the pipe section 1 1, in which the set of membrane cells 9 is located, is at least 300 cm, it can be guaranteed that atmospheric air will get larger partly not through narrow slots and gaps in the structural elements of room 1, but through a set of membrane cells 9, which has a lower hydraulic resistance. At the same time, air entering the set of membrane cells 9 and moving between the membrane cells 10 due to the pressure drop across the membranes created by the vacuum pump 13 will automatically be enriched with nitrogen.

 The proposed invention in a complex for creating and maintaining a hypoxic atmosphere in confined spaces additionally provides a receiver 3, designed to fill it with nitrogen with

SUBSTITUTE SHEET (RULE 26) concentration of 97-99% using a nitrogen generator 2. Its volume depends on the volume of the room. Receiver 3 is designed to extinguish a fire in the event of a sharp (sudden, emergency) depressurization of a room and the occurrence of a fire. In this case, the receiver 3 quickly releases nitrogen into the flame zone and extinguishes the fire.

 Industrial applicability. The present invention can be implemented on the basis of well-known technical means, structural materials, instrumentation, software, and does not require detailed study of individual units and parts, which can be done when designing specific objects using standard methods.

 In the presence of a set of flat hollow membrane cells made, for example, of polyvinyltrimethylsilane, and an additional receiver, there is no need to use high-performance expensive nitrogen generators. In order to create the necessary gas environment in the room and fill the receiver, the time to reach the set parameters is not of particular importance, therefore, a low-capacity generator can be used.

 As for maintaining the composition of the hypoxic mixture in the room, removing harmful impurities and filling the receiver with nitrogen, this is solved by low capital and energy costs due to the implementation of the distinguishing features of the present invention.

SUBSTITUTE SHEET (RULE 26)

Claims

Claim 1. A technical complex for creating and maintaining an atmosphere with a low oxygen content in enclosed spaces, including a nitrogen generator (2) with an inlet pipe located outside the room (1), a pipeline for supplying a hypoxic mixture to the internal volume of the room, device conditioning the gas mixture (4) in the room (1) with a system (5) for monitoring the temperature and composition of the gas mixture by components, lock rooms (6) with hermetic doors and a control system (22), characterized in that the room ( 1), contrary On the outside wall, outside of which there is a nitrogen generator (2), a pipe section (1 1) is mounted that connects the internal volume of the room (1) with the outside atmosphere and is equipped with a set of (9) flat hollow membrane cells assembled in a bag (10) ) with distance hollow spacers (12) between them, selective for oxygen, connected in turn through the internal cavity of the set (9) with a vacuum pump (13), and along the intercellular cavity with the room (1). 2. The technical complex according to claim 1, characterized in that the gaps between the flat hollow membrane cells (10) are from 1 to 3 mm, and the total free passage area of the pipe section (1 1) is at least 300 cm. 3. The technical complex according to claim 1, characterized in that a pipe (21) connecting the internal volume of the room (1) is built into the wall of the room (1), opposite the wall outside which the nitrogen generator (2) is located; with the inlet pipe of the nitrogen generator (2). 4. The technical complex according to claim 1, characterized in that the nitrogen generator (2) is equipped with an additional membrane section (7), selective for sulfur dioxide, hydrogen sulfide, ammonia, located between the inlet of the nitrogen generator (2) and the outlet of the pipeline (21), connecting SUBSTITUTE SHEET (RULE 26) the internal volume of the room (1) and the inlet pipe of the nitrogen generator (2).  5. The technical complex according to claim 1, characterized in that the nitrogen generator (2) is equipped with hollow polymer fibers that are selective for oxygen. 6. The technical complex according to claim 1, characterized in that the nitrogen generator (2) is equipped with flat cells based on a flat gas-permeable membrane, selective for oxygen, sulfur dioxide, hydrogen sulfide, ammonia. 7. The technical complex according to claim 1, characterized in that the flat hollow membrane cells (10) assembled in the package (9) are made of polyvinyltrimethylsilane. SUBSTITUTE SHEET (RULE 26)