JP5554649B2 - Gas generation method and gas generation apparatus - Google Patents

Description

  The present invention relates to a gas generation method for generating a product gas having a high concentration of a concentration target gas such as oxygen gas by adsorbing and separating a target gas such as nitrogen gas from a source gas such as air, and the gas generation The present invention relates to a gas generator that can be suitably used in a method.

  Contains an adsorbent that selectively adsorbs nitrogen gas (adsorption target gas) as a gas generation method that generates oxygen-enriched gas (product gas) with increased oxygen gas (concentration target gas) concentration from the air (source gas). There is known a method in which a plurality of adsorption towers are used and the adsorption process and the regeneration process are alternately switched in each adsorption tower. In the adsorption step, the source gas is supplied to one of the plurality of adsorption towers to increase its internal pressure, and nitrogen gas is adsorbed by the adsorbent accommodated in the one adsorption tower, thereby increasing the oxygen concentration. The regeneration process is a process for reducing the internal pressure of another adsorption tower that has completed the adsorption process among a plurality of adsorption towers, and is adsorbed by an adsorbent accommodated in the other adsorption tower. This is a step of regenerating the adsorbing ability of the adsorbent by desorbing the nitrogen gas that has been discharged and discharging it to the outside. A product gas storage tank for temporarily storing the produced product gas is connected to the adsorption tower.

  As described above, the method of generating the product gas while switching between the adsorption process and the regeneration process is called a pressure swing adsorption (PSA) method, and the gas generation apparatus used therefor is a pressure fluctuation adsorption type gas. It is called a generator. In the conventional pressure fluctuation adsorption-type gas generation method, an adsorption tower that has completed the adsorption process and an adsorption tower that performs the next adsorption process (an adsorption tower that has completed the regeneration process) communicate with each other, and the adsorption process is completed. A pressure equalization step is also performed in which the gas remaining in the tower is transferred to the inside of the adsorption tower where the adsorption step is performed next. By performing this pressure equalization step, the gas that remains in the adsorption tower after the adsorption step (the gas whose oxygen concentration has increased to some extent) is used to increase the internal pressure of the adsorption tower in which the next adsorption step is performed. Therefore, the oxygen recovery rate can be increased.

  The pressure fluctuation adsorption type gas generation method includes not only a method using two adsorption towers (see, for example, Patent Document 1) but also a method using three adsorption towers (see, for example, Patent Document 2). There are also methods using four or more adsorption towers. In the gas generation method using three or more adsorption towers, in addition to the adsorption process and the regeneration process described above, the pressure increasing process can be performed in the remaining adsorption towers. The pressurization step is a step of increasing the internal pressure of the remaining adsorption tower in advance by supplying the raw material gas to the remaining adsorption tower where the adsorption process is performed next. In the adsorption tower that has undergone this pressure increasing step, the subsequent adsorption step can be started in a state where the internal pressure is increased, so that a product gas having a high oxygen concentration can be generated immediately after the adsorption step is started. A gas generation method using three or more adsorption towers is mainly used in industrial applications because a product gas having a high oxygen concentration can be continuously taken out in large quantities.

  By the way, in these pressure fluctuation adsorption type gas generation methods, in order to more efficiently regenerate the adsorption capacity of the adsorbent in the regeneration step, a purge gas is blown into the adsorption tower in the regeneration step, and the inside of the adsorption tower. The stagnant gas is also expelled to the outside. A nitrogen-enriched gas that contains a large amount of nitrogen gas desorbed from the adsorbent is retained inside the adsorption tower in the regeneration process. By removing this nitrogen-enriched gas with a purge gas, the adsorption capacity of the adsorbent is increased. Can be reproduced more effectively. Such an operation is often referred to as “cleaning”. In the conventional pressure fluctuation adsorption type gas generator, as the purge gas for cleaning the adsorption tower, the product gas stored in the product gas storage tank or the product gas inside the adsorption tower immediately after the adsorption step is taken out The gas remaining in the vicinity of the end of the gas can be used as it is, which can be identified with the product gas.

  For example, in Patent Document 1, a part of concentrated oxygen (product gas) stored in a gas reservoir (product gas storage tank) is caused to flow back to an adsorption tank (adsorption tower) in a desorption process (regeneration process). , Cleaning the adsorption tank (see paragraph 0018 and FIG. 2). Further, in Patent Document 2, a hardly adsorbable gas (a gas that can be substantially identified as a product gas) remaining near the upper end of the adsorption tower after the adsorption process is transferred to the adsorption tower in the vacuum desorption process. Thus, it is described that the hard-to-adsorb gas is forcibly pushed out from the adsorption tower after the adsorption step (see claim 1).

  However, with the conventional pressure fluctuation adsorption type gas generation method that uses product gas or gas that can be identified with it as purge gas, it is difficult to maintain the internal pressure of the product gas storage tank high, and the product gas is kept at a high pressure (extraction pressure). It was difficult to take out. Further, in the conventional pressure fluctuation adsorption type gas generation method, since a large amount of oxygen gas is consumed for cleaning the adsorption tower, it is difficult to increase the oxygen recovery rate while keeping the oxygen concentration of the product gas high. It was.

JP-A-10-113527 Japanese Patent Laid-Open No. 07-108126

  The present invention has been made to solve the above-described problems, and enables the adsorption tower to be washed without using the product gas generated in the adsorption step as a purge gas, and the product gas is taken out at a high extraction pressure. An object of the present invention is to provide a pressure fluctuation adsorption type gas generation method that can be used. It is another object of the present invention to provide a pressure fluctuation type gas generation method capable of increasing both the concentration of the gas to be concentrated in the product gas and the recovery rate of the gas to be concentrated. Furthermore, it is also an object of the present invention to provide a pressure fluctuation adsorption type gas generation device that can be suitably used in the pressure fluctuation adsorption type gas generation method of the present invention.

The above problem uses at least three adsorption towers AT ₁ , AT ₂ , AT ₃ , and [1] the primary of one adsorption tower (adsorption tower AT _α ) among the adsorption towers AT ₁ , AT ₂ , AT ₃ . end side (end portion on the side of the raw material gas in the adsorption tower is supplied.) in the raw material gas by supplying increasing the internal pressure of the adsorption tower aT _alpha, adsorption target gas contained in the raw material gas adsorption column aT _alpha An adsorbing step of generating a product gas in which the concentration of the gas to be enriched contained in the raw material gas is increased by adsorbing the adsorbent contained in the adsorbent, and [2] the adsorption towers AT ₁ , AT ₂ , AT ₃ Among them, the internal pressure of the other adsorption tower (adsorption tower AT _β ) that has completed the adsorption process is lowered, and the adsorption target gas adsorbed by the adsorbent accommodated in the adsorption tower AT _β is desorbed and adsorbed. by discharging to the outside of the tower AT _beta, re adsorbability of the adsorbent A reproducing step of, the [3] the adsorption tower AT _1, AT _2, then the raw material gas to the end of the primary side of the rest of the adsorption tower at which the adsorption step is carried out (. To adsorption column AT _gamma) of AT ₃ The pressure fluctuation adsorption type gas generation that generates the product gas by repeatedly performing the pressure increasing step for increasing the internal pressure of the adsorption tower AT _γ in advance by sequentially switching the adsorption towers AT ₁ , AT ₂ , AT _3. Among the raw material gases supplied to the adsorption tower AT _γ in the pressurizing step, the product gas whose concentration of the gas to be enriched has increased from the beginning by reaching the secondary end of the adsorption tower AT _γ Further, a gas having a lower concentration of the gas to be concentrated is extracted from the end on the secondary side of the adsorption tower AT _γ (the end on the side where the product gas is taken out in the adsorption tower. The end opposite to the primary side). The extracted gas is used in the regeneration process. It is solved by providing a gas generating method of the pressure swing adsorption type which is characterized by blowing a purge gas to the adsorption tower AT _beta.

Thus, it is possible to suppress the consumption of the product gas by using the gas extracted from the adsorption tower AT _γ in the pressurization process instead of the product gas as the purge gas blown into the adsorption tower AT _β in the regeneration process. Become. For this reason, it becomes possible to take out substantially all the product gas produced | generated by the adsorption | suction process as product gas as it is. Therefore, the extraction pressure of the product gas, it also becomes possible to increase the inside pressure and the same degree of adsorption column AT _alpha just before the adsorption step is completed. It is also possible to increase the recovery rate of the gas to be concentrated.

By the way, in the gas generation method of the present invention, “at least three adsorption towers AT ₁ , AT ₂ , AT ₃ are used”. However, even if four or more adsorption towers are used, the gas generation of the present invention is performed. It means that the method is feasible. For example, even when four or more adsorption towers are used, the adsorption process, the regeneration process, or the pressurization process is simultaneously performed in two or more adsorption towers (one of the adsorption towers AT _α , AT _β , AT _γ The pressure fluctuation adsorption type gas generation method of the present invention is provided by providing a dormant adsorption tower in which any of the adsorption process, the regeneration process, and the pressure raising process is not performed. It can be easily realized.

In the gas generation method of the present invention, the gas extracted from the adsorption tower AT _γ in the pressure increasing process may be directly blown into the adsorption tower AT _{β in the} regeneration process. However, it is preferable to use a purge gas storage tank for temporarily storing the gas extracted from the adsorption tower AT _γ and to blow the purge gas into the adsorption tower AT _β through the purge gas storage tank. Thus, by suppressing reduce pressure fluctuations of the purge gas blown into the adsorption tower AT _beta (pulsation), it is possible to reproduce stably the adsorbability of the adsorbent.

Further, the above-described problem includes at least three adsorption towers AT ₁ , AT ₂ , AT ₃ , and [1] one adsorption tower (adsorption tower AT _α ) among the adsorption towers AT ₁ , AT ₂ , AT ₃ . the raw material gas is supplied enhance the internal pressure of the adsorption tower AT _alpha in the ends of the primary side of, by adsorption on the adsorbent which is housed inside the adsorption tower AT _alpha adsorption target gas contained in the raw material gas, An adsorption step for generating a product gas with an increased concentration of the gas to be concentrated contained in the source gas, and [2] another adsorption tower (adsorption tower AT) that has completed the adsorption step among the adsorption towers AT ₁ , AT ₂ , AT _{3 β} )), the adsorption target gas adsorbed by the adsorbent accommodated in the adsorption tower AT _β is desorbed and discharged to the outside of the adsorption tower AT _β . a reproduction step of reproducing adsorbability, [3] the adsorption tower _AT 1, a By supplying the raw material gas to the end of the primary side of the _2, AT remaining adsorption tower next adsorption step is carried out of the _three (. To adsorption column AT _gamma), advance the internal pressure of the adsorption tower AT _gamma The pressure increasing process for increasing is repeatedly performed by sequentially switching the adsorption towers AT ₁ , AT ₂ , AT ₃ , thereby generating a product gas, a pressure fluctuation adsorption type gas generating apparatus, which is used in the adsorption tower AT _γ in the pressure increasing process. Of the supplied raw material gas, the concentration of the gas to be enriched is higher than the original by reaching the end on the secondary side of the adsorption tower AT _γ , but the gas having a lower concentration of the gas to be enriched than the product gas is adsorbed to the adsorption tower AT. together withdrawn from the end portion of the secondary side of the _gamma, the pressure swing adsorption-type gas, characterized in that it comprises a purge gas transfer conduit for injecting the withdrawn gas as a purge gas to the adsorption tower AT _beta in regeneration step Also solved by providing a generator. This gas generating apparatus of the present invention can be suitably used for performing the above-described gas generating method of the present invention. The purpose of the gas generating apparatus of the present invention is the same as that of the gas generating method of the present invention.

  As described above, according to the present invention, it is possible to clean the adsorption tower without using the product gas generated in the adsorption process as a purge gas, and the pressure fluctuation adsorption type that can take out the product gas at a high extraction pressure. It becomes possible to provide a gas generation method. It is also possible to provide a pressure fluctuation type gas generation method capable of increasing both the concentration of the gas to be concentrated in the product gas and the recovery rate of the gas to be concentrated. Furthermore, it is possible to provide a pressure fluctuation adsorption type gas generation apparatus that can be suitably used in the pressure fluctuation adsorption type gas generation method of the present invention.

It is the block diagram which showed the gas production | generation apparatus of this invention. It is a timing chart which operates the gas production | generation apparatus of this invention. It is the block diagram which showed the flow of the gas in the gas production | generation apparatus of this invention in a 1st process. It is the block diagram which showed the flow of the gas in the gas production | generation apparatus of this invention in a 2nd process. It is the block diagram which showed the flow of the gas in the gas production | generation apparatus of this invention in a 3rd process. It is the block diagram which showed the flow of the gas in the gas production | generation apparatus of this invention in a 4th process. It is the block diagram which showed the flow of the gas in the gas production | generation apparatus of this invention in a 5th process. It is the block diagram which showed the flow of the gas in the gas production | generation apparatus of this invention in a 6th process.

1. Outline of Gas Generation Method and Gas Generation Apparatus A preferred embodiment of the gas generation method of the present invention and the gas generation apparatus of the present invention used therefor will be described more specifically with reference to the drawings. The gas generation method of the present invention is performed using the gas generation apparatus of the present invention shown in FIG. FIG. 1 is a block diagram showing a gas generator of the present invention. FIG. 2 is a timing chart for operating the gas generator of the present invention. FIG. 3 is a block diagram showing a gas flow in the gas generator of the present invention in the first step. FIG. 4 is a block diagram showing the gas flow in the gas generator of the present invention in the second step. FIG. 5 is a block diagram showing a gas flow in the gas generating apparatus of the present invention in the third step. FIG. 6 is a block diagram showing a gas flow in the gas generator of the present invention in the fourth step. FIG. 7 is a block diagram showing the gas flow in the gas generating apparatus of the present invention in the fifth step. FIG. 8 is a block diagram showing a gas flow in the gas generating apparatus of the present invention in the sixth step.

2. Gas generator gas generator of the present embodiment, as shown in FIG. 1, has a configured to generate a product gas G ₂ captures raw material gas G ₁ from the outside, the three adsorption columns AT _1, AT ₂ , AT ₃ and one purge gas storage tank PT. Each of the adsorption towers AT ₁ , AT ₂ , AT ₃ contains an adsorbent that selectively adsorbs a specific gas (adsorption target gas) under pressure. That is, the gas generating device, the adsorption tower _{AT 1,} AT 2, internally supplying the material gas _{G 1} to the AT ₃ increases the internal pressure of the adsorption tower _{AT 1, AT 2, AT 3} , the raw material gas _{G 1} adsorption target gas contained separated by adsorption on the adsorbent, by increasing the concentration of the specific gas other than adsorption target gas (enriched target gas) contained in the raw material gas G _1, concentrated target gas enriched It has become one of the pressure swing adsorption type which generates a product gas G _2.

Type of the raw material gas G ₁ to be used, the application (type of adsorption target gas and concentrated target gas) of the gas generator and, also vary depending on the location of the gas generator is not particularly limited. The gas generation apparatus of this embodiment concentrates oxygen gas contained in air by adsorbing and removing nitrogen gas contained in air. In other words, the gas generator of the present embodiment, using air as a source gas G _1, be adsorbed gas was nitrogen gas, the enriched target gas and oxygen gas, the product gas oxygen enriched gas oxygen gas enriched G _{2 to} be taken out. Air, because there inexhaustible in the peripheral device, can be easily obtained as the raw material gas G _1. The gas generation apparatus (oxygen-enriched gas generation apparatus) of this embodiment can be suitably used for industrial applications that use a large amount of oxygen gas. Specifically, it is used as a raw material for generating oxygen gas blown into an electric furnace by electric furnace steelmaking, for generating oxygen gas blown as aeration gas into water to be treated by water treatment, or for generating ozone. It can be suitably used for generating oxygen gas.

The kind of the adsorbent filled in the adsorption towers AT ₁ , AT ₂ , AT ₃ varies depending on the kind of the adsorption target gas and is not particularly limited. When the adsorption target gas is nitrogen gas as in the gas generating apparatus of this embodiment, a nitrogen adsorbent that selectively adsorbs nitrogen gas is used. As the nitrogen adsorbent, synthetic zeolite such as A-type zeolite and X-type zeolite can be preferably used. In particular, X-type zeolite is preferable for exhibiting excellent adsorption ability to nitrogen gas, and among X-type zeolites, those exchanged with sodium ions and those exchanged with lithium ions have a small pressure difference. in is optimal in order to be able to more adsorbing nitrogen gas contained in the raw material gas G _1. The adsorbent may be filled only in a part of the inside of the adsorption towers AT ₁ , AT ₂ , AT ₃ , but usually the entire adsorbent AT ₁ , AT ₂ , AT ₃ extends from the lower end to the upper end. Filled.

In the gas generating apparatus of this embodiment, as shown in FIG. 2, the first to sixth steps are repeatedly performed. When the first to sixth steps are repeated, in each of the adsorption towers AT ₁ , AT ₂ , AT ₃ , the adsorption step, the pressure equalization step (decompression side), the regeneration step, the pressure equalization step (pressure increase side) ) And the boosting step are sequentially switched. When the sixth step is completed, the first step is started again, and this loop is repeated as long as the gas generation device is operated . For each step of these will be described in detail later.

Each part of the gas generating apparatus of the present embodiment will be described in more detail. For convenience of explanation, the adsorption tower in the adsorption step among the adsorption towers AT ₁ , AT ₂ , AT ₃ is referred to as “adsorption tower AT _α ”. Is written. Of the adsorption towers AT ₁ , AT ₂ , AT ₃ , the adsorption tower in the regeneration step is denoted as “adsorption tower AT _β ”. Further, among the adsorption towers AT ₁ , AT ₂ , AT ₃ , the adsorption tower in the pressure increasing process is denoted as “adsorption tower AT _γ ”. Furthermore, the adsorption tower in the pressure equalization step (decompression side) is denoted as “adsorption tower AT _δ ”. The adsorption tower in the pressure equalization step (pressure increase side) is denoted as “adsorption tower AT _ε ”. “AT _α ”, “AT _β ”, and “AT _γ ” are symbols for relatively specifying the adsorption tower, and any of the adsorption towers AT ₁ , AT ₂ , AT ₃ is “adsorption tower AT _α ”, “ Whether it becomes the “adsorption tower _ATβ ” or “adsorption tower _ATγ ” varies depending on the timing, as shown in FIGS.

(1) Raw material gas supply valve In the gas generator of this embodiment, the lower ends of the adsorption towers AT ₁ , AT ₂ , AT ₃ are, as shown in FIG. 1, raw material gas supply valves V ₁₀ , V ₂₀ , V, respectively. ₃₀ is connected to a common source gas supply conduit (source gas supply line L ₁ ). These source gas supply valves V ₁₀ , V ₂₀ , V ₃₀ control the timing of performing the adsorption process. As the source gas supply valves V ₁₀ , V ₂₀ , and V ₃₀ , electromagnetic valves that can be electrically controlled are usually used. As the source gas supply valves V ₁₀ , V ₂₀ , and V ₃₀ , electromagnetic valves that can be switched between an open state and a closed state are usually used.

(2) a source gas supply line source gas supply line L ₁ is typically connected to a gas transfer means, not shown. Gas transfer means is not particularly limited as long as it can transport a raw material gas G _1, it is possible to use various devices. In the gas generator of this embodiment, a compressor (not shown) is used as the gas transfer means. By this compressor, the source gas G ₁ is supplied from the outside of the apparatus to the source gas supply line L ₁ . The raw material gas G ₁ flowing through the raw material gas supply line L ₁ is compressed by the gas transfer means and the pressure is increased.

(3) Lower equalizing valve Further, in the gas generating device of this embodiment, as shown in FIG. 1, the lower end portions of the adsorption towers AT ₁ , AT ₂ , AT ₃ are respectively provided with lower equalizing valves V ₁₁ , V ₂₁ , It is also connected to a common lower pressure equalizing gas transfer conduit (lower pressure equalizing gas transfer line L ₂ ) via V ₃₁ . These lower pressure equalizing valves V ₁₁ , V ₂₁ , and V ₃₁ control timing for performing lower pressure equalization described later in the pressure equalizing process. As the lower pressure equalizing valves V ₁₁ , V ₂₁ , and V ₃₁ , electromagnetic valves that can be switched between an open state and a closed state are usually used.

(4) a lower pressure equalizing gas transfer line lower pressure equalizing gas transfer line L _2, as shown in FIG. 1, via a step-up gas supply valve V _40, and is connected to the source gas supply line L _1. Therefore, when you open the boost gas supply valve V _40, as shown in FIG. 4, 6, 8, the lower part of the raw material gas G ₁ flowing through the raw gas supply line L ₁ pressure equalizing gas transfer line L ₂ to flow, thereby making it possible to supply the raw material gas G ₁ flowing into the the bottom end of the adsorption tower AT _gamma in the boosting process. Therefore, the lower pressure equalizing valves V ₁₁ , V ₂₁ , and V ₃₁ control not only the timing for performing the lower pressure equalization but also the timing for performing the pressure increasing process. In the following, in order to distinguish between the raw material gas G ₁ supplied to the adsorption tower AT _α in the adsorption step and the raw material gas G ₁ supplied to the adsorption tower AT _γ in the pressurization step, the latter raw material gas G ₁ is used. ₁ may be expressed as “pressurized gas G ₅ ”.

(5) Pressure increase gas supply valve As the pressure increase gas supply valve V ₄₀ , a mode in which a flow rate control valve capable of adjusting the valve opening is used alone, a mode in which an electromagnetic valve is combined with the flow rate control valve, a solenoid valve, For example, a configuration using an orifice having a throttling function is suitable. Thus, by making the pressurization gas supply valve V ₄₀ have a flow rate adjusting function or a throttling function, the flow rate of the raw material gas G ₁ (pressurization gas G ₅ ) passing through the pressurization gas supply valve V _40. It becomes possible to adjust the pressure increase rate of the adsorption tower AT _{γ in} the pressure increase step. Therefore, the boost just before the adsorption tower AT _gamma is in switching to the next adsorption step in the process, the adsorption tower inside pressure of the AT _gamma is, then the adsorption tower AT adsorbed and equalizing pressure switching pressure of _alpha (adsorption step in the adsorption process it is also easy to adsorption column aT _alpha is adjusted to be the same as the next pressure equalization step the internal pressure of the adsorption tower aT _alpha just before switching to the (pressure decrease)) in. Therefore, it also becomes possible to perform the adsorption process followed by adsorption column AT _gamma more efficiently.

(6) Exhaust Valve Furthermore, in the gas generator of this embodiment, as shown in FIG. 1, the lower end portions of the adsorption towers AT ₁ , AT ₂ , AT ₃ are exhaust valves V ₁₂ , V ₂₂ , V ₃₂ , respectively. Are connected to the silencers S ₁ , S ₂ , S ₃ independent of each other. These exhaust valves V ₁₂ , V ₂₂ and V ₃₂ are for controlling the timing of performing the regeneration process. As the exhaust valves V ₁₂ , V ₂₂ , and V ₃₂ , electromagnetic valves that can switch between an open state and a closed state in a binary manner are usually used. As shown in FIGS. 4, 6, and 8, the silencers S ₁ , S ₂ , and S ₃ are connected to the outside of the apparatus while suppressing the sound of the exhaust gas G _{7 that has} escaped from the adsorption towers AT ₁ , AT ₂ , and AT ₃ . It becomes what is discharged.

(7) Product Gas Delivery Valve In the gas generator of this embodiment, the upper ends of the adsorption towers AT ₁ , AT ₂ , AT ₃ are the product gas delivery valves V ₁₃ , V ₂₃ , V, respectively, as shown in FIG. ₃₃ is connected to a common product gas delivery conduit (product gas delivery line L ₃ ). These products gas delivery valve _{V 13, V 23, V 33,} as shown in FIG. 3-8, which is intended to control the timing of taking out the product gas _{G 2} from the adsorption tower AT _alpha in the adsorption step. As the product gas delivery valves V ₁₃ , V ₂₃ , and V ₃₃ , electromagnetic valves that can be switched between an open state and a closed state are usually used, but a check valve may be used.

(8) The product gas delivery line product gas delivery line L _3, usually, the product gas storage tank for temporarily storing the product gas G ₂ (not shown) is connected. That is, the product gas G ₂ which has been transmitted from the adsorption tower AT _alpha in the adsorption step, after being temporarily stored in the product gas storage tank would be made available is removed from the product gas storage tank. Thus, by providing the product gas storage tank by suppressing small variations in the extraction pressure when taking out the product gas G ₂ which utilizes outside the apparatus (pulsation), take out the product gas G ₂ to stably device external It becomes possible. On the side to take out the product gas G ₂ in the product gas storage tank is taken out flow rate control means for regulating the flow rate of the product gas G ₂ (not shown) and the humidity regulating means for regulating the humidity of the product gas G ₂ Various product gas adjusting means (not shown) such as (not shown) are attached. This product gas regulating means, is the adjustment according to product gas G ₂ applications.

(9) Upper equalizing valve Further, in the gas generator of this embodiment, as shown in FIG. 1, the upper end portions of the adsorption towers AT ₁ , AT ₂ , AT ₃ are respectively connected to the upper equalizing valves V ₁₄ , V ₂₄ , through V _34, it is also connected to a common upper pressure equalization gas transfer conduit (upper BuHitoshi圧gas transfer line L _4). These upper pressure equalizing valves V ₁₄ , V ₂₄ , and V ₃₄ control the timing of performing upper pressure equalization described later in the pressure equalizing process. As the upper pressure equalizing valves V ₁₄ , V ₂₄ , and V ₃₄ , electromagnetic valves that can normally switch between an open state and a closed state are used.

(10) Purge valve Further, in the gas generator of this embodiment, as shown in FIG. 1, the upper end portions of the adsorption towers AT ₁ , AT ₂ , AT ₃ are purge valves V ₁₅ , V ₂₅ , V ₃₅ , respectively. To the purge gas transfer conduit (purge gas transfer line L ₅ ). The purge gas transfer line L _5, purge gas storage tank PT is interposed. As shown in FIGS. 4, 6, and 8, these purge valves V ₁₅ , V ₂₅ , and V ₃₅ are adsorbed among the raw material gas G ₁ (pressurized gas G ₅ ) supplied to the adsorption tower AT _γ in the pressurization process. more product gas G ₂ of those than originally reached the upper end of the column AT _gamma increased the concentration of the enriched target gas withdrawn part concentration of low boost gas G ₅ concentration target gas as a purge gas G _6, purge gas reservoir It controls the timing for storing the tank PT, which is intended to control the timing of supplying the adsorption tower AT _beta with a purge gas G ₆ pooled in the purge gas storage tank PT in the regeneration step. As the purge valves V ₁₅ , V ₂₅ , and V ₃₅ , electromagnetic valves that can be switched between an open state and a closed state are usually used. If necessary, the purge gas transfer line L ₅ is provided a throttle valve such as an orifice, may adjust the flow rate of the purge gas G _6.

(11) Purge gas storage tank The capacity of the purge gas storage tank PT varies depending on the capacity of the adsorption towers AT ₁ , AT ₂ , AT ₃ , and is not particularly limited. However, too small a volume of purge gas storage tank PT, it may become impossible to blow stably purge gas G ₆ to the adsorption tower AT _beta in the regeneration step. On the other hand, if the volume of the purge gas storage tank PT is too large, it is difficult to maintain the internal pressure of the purge gas storage tank PT high, and it may be difficult to blow the purge gas G ₆ at a high pressure into the adsorption tower AT _β in the regeneration process. . Thus, the ratio _C PT _{/ C AT} adsorption towers _{AT 1, AT 2, AT 3} ( a _{C AT.)} Each volume purge gas storage tank PT volume for _(. To _{C PT)} is usually 0. 01 to 1. The ratio _C PT _{/ C AT} is preferable to be 0.05 to 0.5, more preferably a 0.1 to 0.3.

(12) Others In the gas generator of the present invention, the raw material gas supply line L ₁ , the lower pressure equalizing gas transfer line L ₂ , the product gas delivery line L ₃ , the upper pressure equalizing gas transfer line L _4, and the purge gas transfer line L ₅ Each connection form is a connection form that is logically the same as that shown in FIG. 1 or that can be operated in the same manner as that shown in FIG. 1 even in a logically different connection form. If they exist, they may be replaced with those connection forms. Accordingly, the raw material gas supply valves V ₁₀ , V ₂₀ , V ₃₀ , the lower pressure equalizing valves V ₁₁ , V ₂₁ , V ₃₁ , the exhaust valves V ₁₂ , V ₂₂ , V ₃₂ , the product gas delivery valves V ₁₃ , V ₂₃ , V ₃₃ , upper pressure equalizing valves V ₁₄ , V ₂₄ , V ₃₄ , purge valves V ₁₅ , V ₂₅ , V ₃₅ , boost gas supply valve V ₄₀ , silencers S ₁ , S ₂ , S ₃ The number and arrangement of these may be changed. For example, the silencers S ₁ , S ₂ , S ₃ may be combined in one place.

In the gas generator of this embodiment, the lower ends of the adsorption towers AT ₁ , AT ₂ , AT ₃ are the primary side (the side to which the raw material gas G ₁ is supplied), and the adsorption towers AT ₁ , AT ₂ , the upper end of AT ₃ is the secondary side (the side from which product gas G ₂ is taken out), but the primary side and the secondary side may be reversed. That is, the upper portion of the adsorption tower _{AT 1, AT 2, AT 3} and the primary side may be the secondary-side lower portion of the adsorption tower _{AT 1, AT 2, AT 3} . In this case, the configuration (flow diagram) of the gas generating device is a form in which the top and bottom of FIG. 1 are reversed.

3. Gas Generation Method Next, the gas generation method of the present invention using the gas generation apparatus of FIG. 1 will be described in detail. In the gas generation method of this embodiment, as described above, the product gas G ₂ is generated from the raw material gas G ₁ by repeatedly performing the first step to the sixth step. Hereinafter, each process from the first process to the sixth process will be described in order.

(1) In the first step the first step, as shown in FIGS. 2 and 3, the adsorption step the adsorption tower AT ₁ is performed, the adsorption tower AT ₂ in pressure equalization step (boost) is performed, the adsorption tower AT ₃ in pressure equalization step (decompression side) is performed. Immediately before the start of the first step, the sixth step was performed as shown in FIGS. In the sixth step, the pressure increasing step is performed in the adsorption tower AT ₁ and the adsorption step is performed in the adsorption tower AT _3. Therefore, the internal pressure of the adsorption tower AT ₁ immediately before the first step is started is It is in a state of increased to the same level and the adsorbent-average pressure switching pressure of the column AT _3. Further, in the sixth step, the adsorption column AT _2, since the regeneration step has been performed, the internal pressure of the adsorption tower AT ₂ immediately before the first step is started, in a state of being reduced to near ambient air pressure Yes.

Immediately before the start of the first step (just before the end of the sixth step), as shown in FIG. 8, the lower pressure equalizing valve V ₁₁ , purge valve V ₁₅ , exhaust valve V ₂₂ , purge valve V ₂₅ , source gas The supply valve V ₃₀ , the product gas delivery valve V ₃₃ and the pressurization gas supply valve V ₄₀ are open, and the other valves are closed. In the first step, as shown in FIG. 3, all the valves that were opened in the sixth step (FIG. 8) are closed, and a raw material gas supply valve V ₁₀ , a product gas delivery valve V ₁₃ , and a lower pressure equalizing valve V are newly added. ₂₁ , by opening the upper pressure equalizing valve V ₂₀ , the lower pressure equalizing valve V ₃₁ and the upper pressure equalizing valve V ₃₄ . The timings for opening and closing these valves may all be the same. However, with respect to take-out the pressure and recovery of the product gas G _2, if it is possible to obtain the same result as if all opened and closed simultaneously, or if it is possible to obtain better results, as described below The timing for opening and closing these valves may be shifted.

[Adsorption tower AT ₁ ]
In the first adsorption column AT ₁ , an adsorption step is performed as shown in FIG. That is, the raw material gas G ₁ flowing through the raw gas supply line L ₁ passes through the raw material gas supply valve V ₁₀ is supplied to the lower portion of the adsorption tower AT _1, by increasing the internal pressure of the adsorption tower AT _1, be adsorbed gas contained in the raw material gas G ₁ is is adsorbed by the adsorbent contained inside the adsorption tower AT _1. In the gas generation process of the present embodiment, from the moment when the raw material gas supply valve V ₁₀ is opened and the instant when the raw material gas supply valve V ₁₀ is closed, it is called "adsorption step in the adsorption tower AT _1".

In the first step, when the raw material gas G ₁ supplied to the adsorption tower AT ₁ in the adsorption step reaches the upper end of the adsorption tower AT ₁ , most of the gas to be adsorbed therein is adsorbed by the adsorbent. Thus, the concentration of the gas to be concentrated that has not been adsorbed by the adsorbent is increasing. This gas having a higher concentration of the gas to be concentrated is sent out as the product gas G ₂ from the upper end of the adsorption tower AT ₁ , passes through the raw material gas delivery valve V ₁₃ , and is sent to the product gas delivery line L ₃ . As described above, the internal pressure of the adsorption tower AT _1, in order to have increased in advance by boosted step in the sixth step, the adsorbent contained in the adsorption tower AT _1, the adsorption step in the first step is started Immediately after the adsorption, the adsorption target gas can be adsorbed.

The extent to which the concentration of the concentration target gas contained in the product gas G ₂ is specifically increased depends on the use of the product gas G ₂ , the type of the raw material gas G ₁ , the adsorption target gas, and the concentration target gas, There is no particular limitation. However, as in the gas generation process of the present embodiment, the raw material gas G ₁ is a air is adsorbed target gas is nitrogen gas, when enriched target gas is oxygen gas is included in the product gas G ₂ The concentration of the gas to be concentrated is usually 90% or more. The concentration of the enriched target gas in the product gas G ₂ is, preferable to be 93% or more, more preferably 95% or more. In the gas generation process of the present embodiment, the concentration of the enriched target gas in the product gas G ₂ is, as will be described later, is approximately 95% (95.1%).

[Adsorption towers AT ₂ and AT ₃ ]
In the adsorption towers AT ₂ and AT ₃ in the first step, a pressure equalization step is performed as shown in FIG. In the gas generation method of this embodiment, the pressure equalization step is achieved by performing lower pressure equalization and upper pressure equalization. In other words, close to the raw material gas G ₁ of those concentration of the gas (to be adsorbed gas remaining in the vicinity of the lower end portion of the adsorption tower AT ₃ just before the first step is started becomes the higher than the raw material gas G ₁ Gas) is taken out from the lower end of the adsorption tower AT _{3 as} a lower pressure equalizing gas G ₃ , and this lower pressure equalizing gas G _{3 is} passed through the lower pressure equalizing valve V ₃₁ , the lower pressure equalizing line L ₂ and the lower pressure equalizing valve V _{21. 2} (lower pressure equalization). In addition, the gas remaining near the upper end of the adsorption tower AT ₃ immediately before the first step is started (the gas whose concentration of the adsorption target gas is higher than the raw material gas G ₁ and close to the product gas G ₂ ). extraction as an upper pressure equalizing gas _{G 4} from the upper end of the adsorption tower AT _3, the upper end of the adsorption column AT ₂ the upper pressure equalization gas _{G 4} upper equalizing valve _{V 34,} through the upper pressure equalizing line _{L 4} and the upper pressure equalizing valve _{V 24} (Equal pressure at the top).

In the gas generation process of this embodiment, calling up at least one closing moment from the moment both are in the open Hitoshi Shimobe valve V ₂₁ and the lower equalizing valve V ₃₁ and "lower pressure equalization of the adsorption tower AT _2, AT ₃ ' It is out. The time from when both the upper pressure equalizing valve V ₂₄ and the upper pressure equalizing valve V ₃₄ are opened to the moment when at least one of them is closed is referred to as “upper pressure equalization of the adsorption towers AT ₂ and AT ₃ ”. The time from the start of either the lower pressure equalization or the upper pressure equalization of the adsorption towers AT ₂ and AT ₃ to the moment when both are finished is called the “pressure equalization process of the adsorption towers AT ₂ and AT ₃ ”. The lower pressure equalizing valve V ₂₁ , the lower pressure equalizing valve V ₃₁ , the upper pressure equalizing valve V _24, and the upper pressure equalizing valve V ₃₄ do not necessarily need to be opened and closed at the same time, and the lower pressure equalizing and the upper pressure equalizing always start and end at the same time. There is no need.

Thus, in the adsorption tower AT ₂ and the adsorption tower AT ₃ in the first step, by performing the lower pressure equalization and the upper pressure equalization, the adsorption whose internal pressure was low immediately after finishing the regeneration step in the sixth step. to increase the internal pressure of the column aT _2, the internal pressure of the adsorption tower aT ₃ which was higher in the internal pressure immediately after completion of the adsorption step of the sixth step is low, the internal of the adsorption tower aT ₃ and the adsorption tower aT ₂ The pressure can be approached. Therefore, the adsorption tower AT ₂ can efficiently perform the pressure-increasing process in the subsequent second process, and the adsorption tower AT ₃ can efficiently perform the regeneration process in the subsequent second process. Become. In this specification and the drawings, even if the adsorption tower is in the same pressure equalization process, the pressure equalization process performed in the adsorption tower on the side where the internal pressure is increased, like the adsorption tower AT _{2 in} the first process, is referred to as “pressure equalization”. Step (pressure increase side) ”, and the pressure equalization step performed in the adsorption tower on the side where the internal pressure becomes lower like the adsorption column AT _{3 in} the first step is expressed as“ pressure equalization step (pressure reduction side) ”. Distinguish.

(2) Second Step In the second step, as shown in FIG. 2 and FIG. 4, the adsorption step is continued in the adsorption tower AT ₁ , but the pressure equalization step (pressure increase) in the first step in the adsorption tower AT ₂ . is switched from the side) to boost process, the adsorption tower AT _3, is switched to the regeneration step from the pressure equalization step of the first step (depressurization). Therefore, the internal pressure of the adsorption tower AT ₁ immediately before the second step is started, although the adsorbent contained in it has increased to the extent capable of adsorbing adsorption target gas, immediately before the second step is started The internal pressures of the adsorption tower AT ₂ and the adsorption tower AT ₃ are slightly higher than the external pressure, but are considerably lower than the internal pressure of the adsorption tower AT ₁ .

In the second step, as shown in FIG. 4, the upper pressure equalizing valve V ₂₄ , the lower pressure equalizing valve V ₃₁ and the upper pressure equalizing valve V _{34 which} were opened in the first step (FIG. 3) are closed. The purge valve V ₂₅ , the exhaust valve V ₃₂ , the purge valve V ₃₅ and the booster gas supply valve V ₄₀ are opened. The raw material gas supply valve V ₁₀ , the product gas delivery valve V ₁₃ and the lower pressure equalizing valve V ₂₁ are kept open from the first step. The timings for opening and closing these valves may all be the same. However, with respect to take-out the pressure and recovery of the product gas G _2, if it is possible to obtain the same result as if all opened and closed simultaneously, or if it is possible to obtain better results, as described below The timing for opening and closing these valves may be shifted.

[Adsorption tower AT ₁ ]
In the adsorption tower AT ₁ of the second step, as described above, the adsorption step is performed subsequent to the first step. Since the adsorption step in the second adsorption column AT ₁ is the same as the adsorption step in the first adsorption column AT ₁ , detailed description thereof is omitted.

[Adsorption tower AT ₂ ]
In the adsorption tower AT ₂ in the second step, as shown in FIG. 4, step-up step is performed. That is, a part of the raw material gas G ₁ flowing through the raw gas supply line L _1, thereby flowing into the lower pressure equalizing line L ₂ through the step-up gas supply valve V ₄₀ (boost gas G ₅ in FIG. _4), the lower Hitoshi after passing through the valve _{V 21,} and supplies to the lower portion of the adsorption tower AT _2. Therefore, the internal pressure of the adsorption tower AT ₂ is gradually increased. Rate of rise in the internal pressure of the adsorption tower AT ₂ can be easily adjusted by adjusting the valve opening degree of the boost gas supply valve V _40. In the gas generation process of the present embodiment, increase the valve opening degree of the boost gas supply valve V ₄₀ is the internal pressure of the adsorption tower AT ₂ to adsorb and equalizing pressure switching pressure of the adsorption tower AT ₁ by the end of the second step It is set to a value that can be Thereby, not only can the adsorption process be efficiently performed in the adsorption tower AT ₂ of the third process, but the flow rate of the raw material gas G ₁ supplied to the lower end of the adsorption tower AT ₁ of the second process is secured as much as possible. it becomes possible to, the adsorption step in the adsorption tower aT ₁ can be performed efficiently in the second step. In the gas generation process of the present embodiment, is calling up at least one closing moment from the moment in which both the lower pressure equalizing valve V ₂₁ and the booster gas supply valve V ₄₀ is opened as "boosting step of the adsorption tower AT _2".

Further, in the gas generation process of the present embodiment, the adsorption column AT ₂ in the second step, as shown in FIG. 4, the adsorption tower AT ₂ of the raw material gas G ₁ supplied from the lower end of _(boost gas G ₅₎ Among them, although the concentration of the gas to be concentrated has reached the upper end of the adsorption tower AT _{2 and} the concentration of the gas to be enriched is higher than the original, a part of the pressurizing gas G ₅ having a concentration of the gas to be enriched lower than the product gas G ₂ is part of the adsorption tower AT _2. taken from the upper part as a purge gas G _6, it is adapted to be temporarily stored in the purge tank PT passes through the purge valve V _25. Purge gas G _6, since it has passed through the adsorbent contained in the adsorption tower AT _2, is considerably higher concentration of enriched target gas than the boost gas G _{5 (raw} material gas G _1). However, from the beginning compared to the product gas G ₂ taken out from the upper portion of the adsorption tower AT ₁ in the adsorption step performed by increasing the internal pressure, the concentration of the enriched target gas in the purge gas G ₆ is low. Difference in concentration of the enriched target gas in the product gas G ₂ and the purge gas G ₆ acts advantageously for increasing the recovery of enriched target gas.

Incidentally, the timing of opening the purge valve V ₂₅ is not necessarily match the beginning of the step-up process of the adsorption tower AT _2. That is, after the both of the lower pressure equalizing valve V ₂₁ and the booster gas supply valve V ₄₀ is opened, it may open the purge valve V ₂₅ after a while. In this way, since the increased internal pressure of the adsorption tower AT ₂ to some extent, become a purge gas G ₆ can be transferred to the purge gas storage tank PT. Therefore, even without using a check valve, the purge gas G ₆ becomes possible to prevent back flow from the purge gas storage tank PT to the adsorption tower AT _2.

However, if the timing of opening the purge valve V ₂₅ is made too late, the internal pressure of the adsorption tower AT ₂ rapidly increases from an early stage, so that the adsorbent accommodated in the adsorption tower AT _{2 that} should be in the pressure increasing process is removed. , at the same level as for adsorbing adsorption target gas adsorbent housed inside the adsorption tower aT ₁ in adsorption step is contained in the raw material gas G _1, adsorbs be adsorbed gas contained in the booster gas G ₅ It becomes like this. This is substantially the same as performing the adsorption process in the adsorption tower AT ₂ of the pressure increasing process, and the concentration of the gas to be concentrated contained in the purge gas G ₆ is increased to the same level as that of the product gas G _2. End up. Therefore, by suppressing the concentration of the concentration target gas in the purge gas G ₆ to be lower than the concentration of the concentration target gas in the product gas G ₂ , one of the objects of the present invention that increases the recovery rate of the concentration target gas may not be achieved. There is. Therefore, purge valve V ₂₅ is the concentration of the enriched target gas contained in the purge gas G ₆ to open at an earlier timing than exceeds a predetermined value.

Or suppressed to a specific extent the concentration of the enriched target gas contained in the purge gas G ₆ also depends on the type of the raw material gas G ₁ and be adsorbed gas or concentrated target gas is not particularly limited. However, too high a concentration of enriched target gas contained in the purge gas G _6, problems arise as described above. Therefore, as the gas generating method of this embodiment, the raw material gas G ₁ is a air, be adsorbed gas is nitrogen gas, when enriched target gas is oxygen gas is included in the purge gas G ₆ the concentration of the enriched target gas is usually is the less than 95% (is prevented from becoming a more concentration of enriched target gas in the product gas G _2.). The concentration of the enriched target gas contained in the purge gas G ₆ is preferably to be 90% or less (about 0.95 times or less with respect to the concentration of the enriched target gas in the product gas G _2), 87% or less (the product gas and more preferably is about 0.9 times or less) with respect to the concentration of the enriched target gas contained in G _2.

On the other hand, if the concentration of the enriched target gas contained in the purge gas G ₆ is too low, it may become impossible to play adsorbability of the adsorbent contained in the adsorption tower AT ₃ in the regeneration step efficiently. Therefore, the concentration of the enriched target gas contained in the purge gas G ₆ is normally set to 75% or more (about 0.8 times or more relative to the concentration of the enriched target gas in the product gas G _2). The concentration of the enriched target gas contained in the purge gas G ₆ is preferably to be (approximately 0.75 times or more with respect to the concentration of the enriched target gas in the product gas G ₂₎ 70% or more, 80% or more (the product gas and more preferably is about 0.85 or higher) against the concentration of enriched target gas contained in G _2. In the gas generation process of the present embodiment, the concentration of the enriched target gas contained in the purge gas G ₆ is set to 85%.

[Adsorption tower AT ₃ ]
In the adsorption tower AT ₃ in the second step, as shown in FIG. 4, the reproduction process is performed. That is, the adsorption tower AT _{3 that} has finished the pressure equalization process (decompression side) following the adsorption process has its internal pressure lowered to near the external pressure, and is adsorbed by the adsorbent in the adsorption tower AT ₃ in the adsorption process. Most of the gas to be adsorbed is separated from the adsorbent and remains in the adsorption tower AT _3. The remaining gas is discharged from the lower end of the adsorption tower AT ₃ to the exhaust valve. V ₃₂ and muffler for exhausting to the outside air outside the apparatus through _{S 3} (exhaust gas _G 7 in FIG. 4). Exhaust gas G ₇ is the concentration of the adsorbed target gas is very high. This makes it possible to reproduce the adsorbability of the adsorbent which is housed in the adsorption tower AT _3. In the gas generation method of this embodiment, the period from the moment when the exhaust valve V ₃₂ is opened to the moment when it is closed is called the “regeneration step of the adsorption tower AT ₃ ”.

In the second adsorption column AT ₃ , as shown in FIG. 4, the purge gas G ₆ stored in the purge tank PT passes through the purge valve V ₃₅ and is then blown from the upper end of the adsorption tower AT _3. It is supposed to be. Thus, in the interior of the adsorption tower AT _3, it is possible to generate a flow of large gas directed from the upper end to the lower end, to facilitate the discharge of the exhaust gas G ₆ from the lower end portion of the adsorption tower AT _3.

That is, when the reproduction process is started in the adsorption tower AT _3, the internal pressure of the adsorption tower AT _3, in order to decrease by the exhaust valve V ₃₅ is opened, to be adsorbed gas from the adsorbent which is housed in it ( In the gas generation method of the present embodiment, nitrogen gas) is desorbed, and the adsorption target component enriched gas containing a large amount of the adsorption target gas (nitrogen enriched gas in the gas generation method of the present embodiment) is adsorbed inside the adsorption tower AT ₃ . Stays on. However, by blowing purge gas G ₆ from the upper portion of the adsorption tower AT _3, the adsorption target component enriched gas expel from the lower end of the adsorption column AT ₃ as an exhaust gas G _7, the regeneration step in the adsorption tower AT ₃ It becomes possible to carry out efficiently. In the conventional gas generator, as a purge gas G _6, because it was using the product gas G _2, it was not taken out only part of the product gas G ₂ generated in the adsorption step. However, in the gas generating apparatus of this embodiment, the product gas G ₂ is not used as the purge gas G ₆ , so that waste of the product gas G ₂ can be suppressed.

Purge valve V ₃₅ for controlling the timing of blowing purge gas G ₆ to the upper portion of the adsorption tower AT ₃ is such as by time of reproducing process, immediately after the adsorption tower AT ₃ was it becomes a regeneration step simultaneously, or the regeneration step You may open it. However, in this case, even if the exhaust valve V ₃₂ is opened, the internal pressure of the adsorption tower AT ₃ is difficult to decrease, and there is a possibility that the adsorption target gas is difficult to desorb from the adsorbent, particularly in the first half of the regeneration process. Also, will be reduced internal pressure of the purge gas storage tank PT, it may become impossible to supply the high pressure of the purge gas G ₆ to the adsorption tower AT ₃ at the end of the regeneration step. Accordingly, the exhaust gas G ₇ hardly flush from the lower end portion of the adsorption tower AT _3, there may not be reproduced sufficiently adsorption capacity of the adsorbent. For this reason, it is preferable that the purge valve V ₃₅ be opened after a while after the exhaust valve V ₃₅ is opened and the adsorption tower AT ₃ is switched to the regeneration process.

The specific timing for opening the purge valve V ₃₅ varies depending on the time of the regeneration process performed in the adsorption tower AT ₃ and is not particularly limited. However, if the timing of opening the purge valve V ₃₅ is too early, the above-described problems may occur, and if it is too late, sufficient time for expelling the exhaust gas G ₇ remaining in the adsorption tower AT ₃ is secured. There is a risk that it will not be possible. Therefore, purge valve V ₃₅ are preferably open from the end of the regeneration step is 20% or more, more preferably to open from the end of 50% or more. On the other hand, the purge valve V ₃₅ are preferably open before the ends regeneration process more than 90%, more preferably opened before the ends 80%. The purge valve V ₃₅ is preferably opened for at least 1 second, preferably 3 seconds, more preferably 5 seconds, immediately before the end of the regeneration step. On the other hand, the purge valve _V35 is normally kept from opening for 20 seconds or more. The purge valve V ₃₅ is preferably not opened for 15 seconds or longer, and more preferably not opened for 10 seconds or longer.

(3) Third Step In the third step, as shown in FIGS. 2 and 5, the adsorption tower AT ₁ is switched from the adsorption step up to the second step to the pressure equalization step (decompression side), and the adsorption tower At AT ₂ , the second pressure increasing step is switched to the adsorption step, and at the adsorption tower AT ₃ , the second regeneration step is switched to the pressure equalizing step (pressure increasing side). The description of the specific operation of the gas generating apparatus of the present embodiment in the third step is the same as that obtained by replacing the words in the text of the above “(1) First step” as shown in Table 1 below. To do.

(4) In a fourth step the fourth step, as shown in FIGS. 2 and 6, the adsorption tower AT _2, although the adsorption step is subsequently performed, a third step of pressure equalization step in the adsorption tower AT ₁ (reduced pressure The adsorption tower AT ₃ is switched from the pressure equalization process (pressure increase side) of the third process to the pressure increase process. The description of the specific operation of the gas generating device of the present embodiment in the fourth step is the same as that obtained by replacing the phrase in the text of the above “(2) Second step” as shown in Table 1 above, and is therefore omitted. To do.

(5) Fifth Step In the fifth step, as shown in FIG. 2 and FIG. 7, the adsorption tower AT ₁ is switched from the regeneration step of the fourth step to the pressure equalization step (pressure increase side). ₂ , the adsorption process up to the fourth process is switched to the pressure equalization process (decompression side), and the adsorption tower AT ₃ is switched from the pressure increase process of the fourth process to the adsorption process. The description of the specific operation of the gas generating apparatus of the present embodiment in the fifth step is the same as that obtained by replacing the words in the text of the above “(1) First step” as shown in Table 2 below. To do.

(6) Sixth Step In the sixth step, as shown in FIGS. 2 and 8, the adsorption step is continued in the adsorption tower AT ₃ , but in the adsorption tower AT ₁ , the fifth pressure equalization step (pressure increase) is switched from the side) to boost process, the adsorption tower AT _2, is switched to the regeneration step from the pressure equalization step of the fifth step (depressurization). The description of the specific operation of the gas generating apparatus of the present embodiment in the sixth step is the same as that obtained by replacing the phrase in the text of the above “(2) Second step” as shown in Table 2 above. To do.

4). Example Using the gas generation method of the present invention, the concentration of the gas to be concentrated (oxygen gas) was actually increased by adsorbing and removing the gas to be adsorbed (nitrogen gas) from the raw material gas G ₁ (air). Product gas G ₂ (oxygen-enriched gas) was generated. The gas generation method of the present invention was performed using the gas generation apparatus of the present invention shown in FIG. The adsorption tower _{AT 1, AT 2, AT 3} , each diameter and a height 89mm was used as the cylindrical volume of about 5288cm ³ of 850 mm. Adsorption towers AT ₁ , AT ₂ and AT ₃ were filled with 3.15 kg of X-type zeolite exchanged with sodium ions as an adsorbent. Supply flow rate of the raw material gas _{G 1} into the raw material gas supply line _{L 1} was 180NL / min. Further, (a set flow rate of the flow rate adjusting means mentioned in the description of the "(8) the product gas delivery line" in "2. Gas generator") of the product gas G ₂ is taken out from the product gas storage tank as described above flow, 20 NL / Minutes. Furthermore, the adsorption / equal pressure switching pressure of the adsorption towers AT ₁ , AT ₂ , AT ₃ was 0.68 MPa, and the switching time was 16 seconds.

After the gas generator is operated under the above conditions and the first to sixth steps are regularly repeated, the internal pressure of the product gas storage tank, the product gas G ₂ taken out from the product gas storage tank extraction pressure, the oxygen concentration in the product gas G _2, and where the oxygen recovery rate was measured, the results shown in table 3 were obtained.

Looking at Table 3 above, it can be seen that the internal pressure of the product gas storage tank changes at a very high level of 0.64 to 0.68 MPa. Further, extraction pressure of the product gas _{G 2} is a 0.62 MPa, also seen to have a very high value. This numerical value of 0.62 MPa is about 91% of 0.68 MPa which is the adsorption / equal pressure switching pressure. In the conventional gas generating method of the same conditions, extraction pressure of the product gas G ₂ is about 40% to 70% of the adsorption and equalizing pressure switching pressure. In view of these, the gas generation process of the present invention, for maintaining a high removal pressure of the product gas G _2, it can be seen very advantageous.

Looking at the above Table 3, it can also be seen that has become oxygen concentration in the product gas G ₂ be 95.1% and very high. Furthermore, it can also be seen that the oxygen recovery rate is as high as 50.3%. The conventional gas generating method of the same conditions, when the oxygen concentration in the product gas G ₂ is trying to increase up to about 95%, oxygen recovery had become 30-40%. Considering these things, it can also be seen that the gas generation method of the present invention is very advantageous for increasing the oxygen concentration of the product gas G ₂ and increasing the oxygen recovery rate.

AT ₁ adsorption tower AT ₂ adsorption tower AT ₃ adsorption tower AT _α adsorption process adsorption tower AT _β regeneration process adsorption tower AT _γ pressure raising process adsorption tower PT purge gas storage tank V ₁₀ source gas supply valve V ₁₁ lower leveling valve V ₁₂ exhaust valves V ₁₃ product gas delivery valve V ₁₄ upper equalizing valve V ₁₅ purge valve V ₂₀ material gas supply valve V ₂₁ lower equalizing valve V ₂₂ exhaust valves V ₂₃ product gas delivery valve V ₂₄ upper equalizing valve V ₂₅ purge valve V ₃₀ source gas supply valve V ₃₁ lower pressure equalization valve V ₃₂ exhaust valve V ₃₃ product gas delivery valve V ₃₄ upper pressure equalization valve V ₃₅ purge valve V ₄₀ pressure increase gas supply valve L ₁ source gas supply line (source gas supply conduit)
L ₂ lower pressure equalizing gas transfer line (lower pressure equalizing gas transfer conduit)
L ₃ product gas delivery line (product gas delivery conduits)
L ₄ upper pressure equalizing gas transfer line (upper pressure equalization gas transfer conduit)
L ₅ purge gas transfer line (purge gas transfer conduit)
S ₁ silencer S ₂ silencer S ₃ silencer G ₁ source gas G ₂ product gas G ₃ lower pressure equalization gas G ₄ upper pressure equalization gas G ₅ pressure increase gas G ₆ purge gas G ₇ exhaust gas

Claims (4)

Using at least three adsorption towers AT ₁ , AT ₂ , AT ₃ ,
The adsorption target contained in the raw material gas is supplied by compressing and supplying the raw material gas to the primary side end of one of the adsorption towers AT ₁ , AT ₂ , AT ₃ to increase the internal pressure of the single adsorption tower. An adsorption step for producing a product gas having an increased concentration of the gas to be concentrated contained in the raw material gas by adsorbing the gas to the adsorbent housed in the one adsorption tower;
Of the adsorption towers AT ₁ , AT ₂ , and AT ₃ , the other adsorption towers that have completed the adsorption process are connected to the outside air to reduce the internal pressure of the other adsorption towers, and the adsorptions accommodated in the other adsorption towers A regeneration step for regenerating the adsorption capacity of the adsorbent by desorbing the adsorption target gas adsorbed by the adsorbent and discharging it to the outside air ;
By supplying the raw material gas while compressing it to the primary side end of the remaining adsorption tower in which the adsorption step is next performed among the adsorption towers AT ₁ , AT ₂ , AT ₃ , the internal pressure of the remaining adsorption tower is reduced. A boosting step to increase in advance;
Is a pressure fluctuation adsorption type gas generation method for generating a product gas by repeatedly performing the above by sequentially switching in the adsorption towers AT ₁ , AT ₂ , AT ₃ ,
Of the raw material gas supplied to the remaining adsorption tower in the pressurization step, the concentration of the gas to be concentrated has increased from the beginning by reaching the secondary side end of the remaining adsorption tower, but it is more concentrated than the product gas A pressure fluctuation adsorption system characterized in that a gas having a low concentration of the target gas is extracted from the secondary side end of the remaining adsorption tower, and the extracted gas is blown as a purge gas into the other adsorption tower in the regeneration process. Gas generation method. Using a purge gas storage tank for temporarily storing the gas extracted from the remaining adsorption tower,
The pressure fluctuation adsorption type gas generation method according to claim 1, wherein the purge gas is blown into the other adsorption tower through the purge gas storage tank. Comprising at least three adsorption towers AT ₁ , AT ₂ , AT ₃ ;
The adsorption target contained in the raw material gas is supplied by compressing and supplying the raw material gas to the primary side end of one of the adsorption towers AT ₁ , AT ₂ , AT ₃ to increase the internal pressure of the single adsorption tower. An adsorption step for producing a product gas having an increased concentration of the gas to be concentrated contained in the raw material gas by adsorbing the gas to the adsorbent housed in the one adsorption tower;
Of the adsorption towers AT ₁ , AT ₂ , and AT ₃ , the other adsorption towers that have completed the adsorption process are connected to the outside air to reduce the internal pressure of the other adsorption towers, and the adsorptions accommodated in the other adsorption towers A regeneration step for regenerating the adsorption capacity of the adsorbent by desorbing the adsorption target gas adsorbed by the adsorbent and discharging it to the outside air ;
By supplying the raw material gas while compressing it to the primary side end of the remaining adsorption tower in which the adsorption step is next performed among the adsorption towers AT ₁ , AT ₂ , AT ₃ , the internal pressure of the remaining adsorption tower is reduced. A boosting step to increase in advance;
Is a pressure fluctuation adsorption type gas generating device that generates product gas by repeatedly performing the above by sequentially switching in the adsorption towers AT ₁ , AT ₂ , AT ₃ ,
Of the raw material gas supplied to the remaining adsorption tower in the pressurization step, the concentration of the gas to be concentrated has increased from the beginning by reaching the secondary side end of the remaining adsorption tower, but it is more concentrated than the product gas A purge gas transfer conduit is provided for extracting a gas having a low concentration of the target gas from the end portion on the secondary side of the remaining adsorption tower and blowing the extracted gas into the other adsorption tower in the regeneration process as a purge gas. A pressure fluctuation adsorption type gas generator characterized by the above.   4. The pressure fluctuation adsorption type gas generator according to claim 3, wherein a purge gas storage tank for temporarily storing the gas extracted from the remaining adsorption tower is interposed in a purge gas transfer conduit.

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