JP2003033618A - Adsorption cylinder for pressure swing adsorption and separation, and pressure swing adsorption separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adsorption cylinder having an optimum shape to an adsorbent with a specific dimension and shape capable of reducing the unit requirement of power when adsorbing and separating oxygen in air by an oxygen PSA, and a pressure swing adsorption separator excellent in pressure swing adsorption separation performance. SOLUTION: In the adsorption cylinder with an adsorbent for separately collecting oxygen in air by the pressure swing adsorption separating method, the size of the adsorbent is set so that the superficial velocity u [m/s] is in a range of ±25% of u=0.07a+0.095 where a [mm] is the diameter when the adsorbent is spherical or the equivalent diameter when the adsorbent is columnar, elliptic spherical or elliptic columnar. In particular, the adsorbent used in an adsorbent tower preferably contains at least 70% of adsorbent particles with the particle size distribution in a range between 12 mesh to 20 mesh, or the diameter or the equivalent diameter (a) of the adsorbent is preferably in a range of 1.0±0.2 mm when the particle size distribution of the adsorbent is measured by Tyler standard sieve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adsorption column for pressure fluctuation adsorption separation and a pressure fluctuation adsorption separation device, and more particularly, it is used for separating and collecting oxygen in air by a pressure fluctuation adsorption separation method. The present invention relates to the shape of an adsorption cylinder capable of performing a pressure fluctuation adsorption separation method under optimum conditions corresponding to the size of an adsorbent, and a pressure fluctuation adsorption separation device using this adsorption cylinder.

[0002]

2. Description of the Related Art By pressure fluctuation adsorption separation method (PSA),
The main operation for separating and collecting the target component gas using the multi-component mixed gas as the source gas is to pressurize the source gas, then introduce it into the adsorption column filled with the adsorbent, and contact the source gas with the adsorbent. An adsorption operation that selectively adsorbs easily adsorbed components in the raw material gas, separates and collects difficultly adsorbed components, and reduces the pressure in the adsorption column to desorb the easily adsorbed components from the adsorbent that adsorbs the easily adsorbed components. And a regeneration operation for regenerating the adsorbent.

The method of the above-mentioned regeneration operation is roughly divided into two, one is a method of reducing the pressure of the adsorption column to atmospheric pressure or less (vacuum regeneration method) and the other is a method of reducing the pressure to atmospheric pressure (normally). There is a pressure regeneration method). The adsorption operation by the vacuum regeneration method is
In order to reduce the compression power of the raw material gas, it is often performed under a pressure condition relatively close to the atmospheric pressure, which is suitable for generating a large volume of product gas. On the other hand, in the normal pressure regeneration method, since the regeneration operation is performed at atmospheric pressure, it is necessary to set the adsorption pressure high in order to obtain a sufficient pressure difference between the adsorption pressure and the atmospheric pressure, and the compression power of the raw material gas increases. However, since it does not require a vacuum pump or a product gas compressor, it is often used when generating a small amount of product gas. In particular, when the source gas is air and the product gas is oxygen, it is often used for medical purposes or the like when it is convenient for supply that a small amount of product oxygen has a slight pressure.

The apparatus used in the pressure fluctuation adsorption separation method is composed of a raw material gas compressor, at least one adsorption column, a product tank, and a vacuum pump or a product for adsorbent regeneration provided as necessary. With a gas pump,
It is formed by a pipe corresponding to a separation process for connecting these devices. Furthermore, in the pressure fluctuation adsorption separation device, a control device such as a computer and a sequencer is used to output an electric signal in accordance with a program of the separation process input in advance to control the opening and closing of the automatic switching valve to control the adsorption / regeneration described above. By repeating the operation, the product gas is separated and collected.

In the adsorbent used in such a pressure fluctuation adsorption separation method, for example, when oxygen is obtained as a product from air, the target component to be adsorbed and removed is nitrogen, so that the adsorbent selectively adsorbs nitrogen. Zeolite is used as an agent. As this zeolite, for example, Ca-A type,
Na-X type, Ca-X type, and Ba-X type are preferable. Recently, zeolites in which Na-X type Na ions are exchanged with various ions, particularly zeolite L in which Li ions are exchanged
The i-X type is widely used.

Regarding the general design method of the pressure fluctuation adsorption separation device, see A. I. References such as LaCava, CHE
MICAL ENGINEERING / JUNE 19
98, pp. 110-118. This document describes in detail the method of designing the components of the pressure swing adsorption separation device.
Starting with an experiment with a small device, the performance obtained in the small experiment gives a higher value than that of an industrial-scale device, so one method of risk avoidance is described to be to make an intermediate-scale pilot device. Subsequently, there is a statement that "the cylinder height of the pilot device should be equal to the required actual device scale. Generally, it is about 2 m." As described in this document, as a general suction cylinder design method, the size of the suction cylinder of the actual device is determined as follows.

First, the adsorbent to be used is determined and an experiment in a small device and an experiment in a pilot device are performed to obtain the product amount per weight of adsorbent used (or per volume). Next, the required adsorbent weight (or adsorbent volume) is determined by dividing the product amount required in the actual device by the product amount generated per adsorbent amount in the preceding paragraph. Then, assuming that the filling height of the adsorption cylinder is the same as in the experiment, the diameter of the adsorption cylinder can be obtained from the relationship of “adsorbent weight = adsorbent filling volume × adsorbent filling density”. By the above method, device design by pressure fluctuation adsorption separation method using various kinds of adsorbents has been performed in the past.

The shape of the adsorbent used here is also various. In particular, the particle size of the adsorbent is generally 1/16
Inch size, 1/8 inch size pellets, 8 ~
Many 12 mesh beads and the like were used, but an adsorbent having a smaller particle size was also used. Usually, when large adsorbent particles are used, the pressure loss of the adsorbent packed bed is small, but the diffusion path of the adsorbed molecules inside the adsorbent becomes long, so the overall mass transfer coefficient becomes small.

On the other hand, when relatively small adsorbent particles are used, it is said that the mass transfer coefficient tends to be large although the pressure loss of the adsorbent packed bed is large. The pressure loss of the adsorbent-packed bed requires a large amount of power to supply the raw material air, and the magnitude of the mass transfer coefficient depends on the so-called adsorption band length (Mass Trans).
Since it is related to the fer zone, it is related to the amount of adsorbent required. Further, when performing vacuum regeneration, there is a problem in that the pressure in the lower part of the adsorption cylinder and the pressure in the upper part of the adsorption cylinder are different, and the degree of regeneration of the adsorbent varies depending on the location in the adsorption cylinder.

For this reason, what size and shape of the adsorbent particle size to be used has been a big problem for the design of the adsorbing device, but it is necessary to quantify how to use the adsorbent of various sizes and shapes. In the past, there was no specific guideline. Therefore, a method for designing an efficient adsorption device, that is, how to minimize the amount of adsorbent used and how to improve the performance as a pressure fluctuation adsorption separation device, in particular, a method for making the device excellent in electric power consumption rate Have been devised in various ways.

For example, Separation Technology Vol. 11, No. 5, p. 11 to 17
(1981) proposes a combination of a small particle size adsorbent and a large particle size adsorbent, taking removal of water in a gas as an example. In this case, by disposing an adsorbent with a large particle size on the upstream side and an adsorbent with a small particle size on the downstream side, it is possible to reduce the pressure loss on the upstream side and reduce the width (length) of the adsorption zone on the downstream side. It is stated that it can be made smaller. That is, when using only a large particle size adsorbent, the pressure loss is small but the amount of adsorbent used is large, and when only the small particle size adsorbent is used, the pressure loss is large but the amount of adsorbent used is large. By combining a small particle size adsorbent and a large particle size adsorbent, the problem of being small is integrated and harmonized, and the contradictory problems of the adsorbents having respective particle sizes are solved. However, regarding the thickness of the bed of the adsorbent layer, the Elghan's equation regarding the pressure loss of the packed bed is shown, and it is only pointed out that the packed porosity is important together with the particle size. How to stack particle size adsorbents and small particle size adsorbents is not suggested.

On the other hand, Japanese Patent Application Laid-Open No. 11-179132 discloses, as a conventional technique, a particle size of an adsorbent to be used and a thickness of a bed of an adsorbent layer at that time, among patents relating to a pressure fluctuation adsorption separation method in the past. , The cycle time of the pressure fluctuation adsorption separation operation was given, and for the particles of the same diameter, the bed thicknesses were significantly different from each other and could not be selected accurately, and the geometrical constraint due to the dead volume in the adsorption cylinder Point out that is not considered.

Further, in the publication, when the thickness of the bed of the adsorbent layer is spherical, the pressure fluctuation substantially depends only on the diameter, and the shape fluctuation of the dead volume is taken into consideration. Disclosed is to provide a pressure fluctuation adsorption separation method that does not have a negative effect on the energy consumption of the adsorption separation method, discloses the relationship between the adsorbent particle size and the thickness of the adsorbent layer bed, and a suitable adsorbent layer bed The range and the suitable range of the adsorbent particle size are shown. But,
There are two variables in the given relational expression, and even if the particle size is determined, only the bed thickness that is usually used within the range of the inequality is widely shown, and particles with this size give the best performance. There is no mention of doing so.

Regarding the design of the adsorption tower used in the pressure fluctuation adsorption separation method, the type of the adsorbent used is determined from those available from the adsorbent manufacturer in consideration of static / dynamic adsorption performance. However, as the particle size of the adsorbent used in the pressure fluctuation adsorption separation device for collecting oxygen, what is the particle size that can maximize the performance of the device, that is, what is the particle size that can reduce the power consumption rate? As to what kind of gas flow rate such an adsorbent should be used for, and how the filling height at that time should be used, as described in the literature such as LaCava et al. There was no means other than the standard, and technical improvement was required.

[0015]

Therefore, the inventors of the present invention use the power consumption unit of a pressure fluctuation adsorption separation device using oxygen as an index, and variously change the particle shape and size of the adsorbent to obtain the power consumption. Various studies were made on the particle shape and size such that the unit was the lowest.

Further, it has been clarified that there is an optimum adsorption cylinder shape for adsorbents having various particle shapes and sizes, that is, there is an optimum gas empty velocity for adsorbent shape characteristics, and the selected adsorption It was found that the pressure fluctuation adsorption separation performance higher than the conventional one can be obtained by determining the diameter of the adsorption cylinder based on the shape characteristics of the agent.

The present invention has been made based on the above findings, and when collecting oxygen in the air as a product by the pressure fluctuation adsorption separation method, an adsorbent of a specific size and shape which can reduce the electric power consumption rate. It is an object of the present invention to provide an adsorption column having an optimal shape and a pressure fluctuation adsorption separation device having excellent pressure fluctuation adsorption separation performance.

[0018]

In order to achieve the above object, an adsorption column filled with an adsorbent for separating and collecting oxygen in air by the pressure swing adsorption separation method of the present invention has a size of the adsorbent. , The diameter when the adsorbent is spherical, and the equivalent diameter when the adsorbent is columnar, elliptical, or elliptic, a
[Mm], the empty cylinder velocity u [m / s] is u =
The feature is that the range is set to ± 25% of 0.07a + 0.095.

In particular, the adsorbent used in the adsorption tower is
When the particle size distribution of the adsorbent is measured with a Tyler standard sieve, the adsorbent particles having a particle size distribution of 12 mesh to 20 mesh contain at least 70% or more, or the adsorbent is Or the equivalent diameter a is 1.
The range is preferably 0 ± 0.2 mm.

In the present invention, the adsorbent is C
a-A type zeolite, Na-X type, Na of the Na-X type
At least a part of the zeolite ion-exchanged with Ca, Mg or Li can be preferably used. Furthermore, it is preferable that the pressure fluctuation adsorption separation method is a pressure fluctuation adsorption separation method in which vacuum regeneration is performed. Further, it is more effective in the case of the pressure fluctuation adsorption / separation device equipped with the adsorption cylinder described above.

Here, the pressure fluctuation adsorption separation process is a non-steady process in which the pressure, temperature, gas flow rate, and gas composition in the adsorption cylinder change intricately with time. Dynamic simulation is effective. The present invention will be described below using dynamic simulation.

Japan Oxygen Technical Report No. 17, p18-24
(1998) describes a simulation method of a pressure swing adsorption separation method (hereinafter referred to as oxygen PSA) using oxygen as a product. Here, the target oxygen PSA
Is a two-column system, and the process consists of charging / product recovery process, pressure equalization process, vacuum regeneration process, purge regeneration process, pressure equalization process, and the theoretical model is assembled under some assumptions. . In addition, the basic equation is the total mass balance,
It consists of mass balance of each component, adsorption rate formula, equilibrium adsorption amount estimation formula, heat balance formula, etc.

Further, the mass balance is such that the air blower discharge pressure is equal to the sum of the air blower air supply amount for supplying the raw material air and the exhaust gas amount of the exhaust vacuum pump for regenerating the product and the adsorbent. And / or the degree of vacuum reached by the vacuum pump is taken as an adjusting element. The material balance determines the conditions of the rotating machine attached to the pressure fluctuation adsorption separation apparatus (PSA apparatus), and therefore the amount of electric power required for the rotating machine is obtained, and thus the electric power which is one of the most important performances for the PSA apparatus. Basic unit is required.

The above-mentioned simulator was loaded with the relational expression of the particle size and the mass transfer coefficient in the particle (Kunitaro Kawazoe: Chemical Engineering, 31.354-358. (1967)) as the adsorbent characteristic, and the adsorbent particle size was obtained. And the adsorption rate were related. Of course, the relationship between the overall mass transfer coefficient and the particle size may be obtained by actual measurement.

Further, since the adsorbent particle diameter is considered to be a factor that directly affects the electric power consumption rate, the Elgan's equation is applied to the adsorbent packed bed and the packed bed height is changed by changing the packed adsorbent particle diameter. The pressure loss in the depth direction was calculated, and the adsorption pressure / regeneration pressure at each height in the adsorption cylinder was obtained to calculate the influence on the product oxygen amount and the consumption power.

Using the simulator, first, in a vacuum regeneration type PSA device (VSA), the adsorbent particle size to be used is determined by setting the air blower capacity, the vacuum pump capacity, and the adsorbent amount to be used under certain conditions. Various amounts of the oxygen gas (for example, 93% O ₂ ) having a specified concentration were obtained by changing the cylinder diameter. Dividing the sum of the power consumption of the air blower and the vacuum pump by the product oxygen gas amount gives the power consumption unit, and the adsorption cylinder diameter when the power consumption becomes the minimum value is the most desirable adsorption cylinder of the adsorbent particle size. Diameter.

On the other hand, the amount of raw material air to be supplied to the PSA device as raw material air is obtained by the above calculation. Here, the raw material air amount is converted into a standard state (0 ° C., 1 atm absolute pressure), and the value divided by the adsorption cylinder cross-sectional area is defined as the empty cylinder velocity. When the adsorbent particle size to be used is changed and the same calculation is performed as described above, the optimum empty cylinder velocity is obtained for each adsorbent particle size.

In addition, in designing the PSA device, a predetermined PS is determined from experiments or simulations.
By performing the operation A, the oxygen recovery rate and the oxygen generation amount per unit amount of the adsorbent can be obtained. That is, with respect to the oxygen amount (pure oxygen equivalent value) required in the actual device, the required raw material air amount = (pure oxygen equivalent) required oxygen amount / (oxygen recovery rate x oxygen content in air) required adsorbent amount = Required oxygen amount / Oxygen generation amount per unit of adsorbent Adsorption column cross section = Required raw air amount / Vacancy velocity Adsorbent filling height = Required adsorbent amount / (Filling density x Adsorption column cross section) Thus, the shape (cylinder diameter) of the suction cylinder can be determined. The oxygen recovery rate is based on the content of oxygen contained in the raw material air.

In the present invention, the adsorbent particle diameter means a diameter for spherical particles and an equivalent diameter for other shapes. For example, in the case of a columnar (pellet-shaped) adsorbent having a diameter d and a height h, assuming that the surface area / volume = (2d + 4h) / (d × h) is a sphere having an equivalent diameter a, By the same equation as above, surface area / volume = 6 / a = (2d + 4
From h) / (d × h), a = 3d × h / (d + 2h).

Regarding such a relationship, Fundam
entals of Adjustment. Proc
needs of the engineerin
gFoundation Conference he
ld at Schloss Elmau, Bavar
ia, West Germany, (1983) p4
However, the equivalent diameter used in the present invention is not limited to this, and includes the diameter determined by a simple method such as the peak value of the particle size distribution or the average value of the distribution. To do.

The adsorbent used in the present invention has the shape and size of the adsorbent generally used in the past, that is, a pellet shape of 1/8 inch size, 1/16 inch size, or 8-12. The diameter or equivalent diameter of 1 mm is calculated by the simulator with respect to the diameter or equivalent diameter of the adsorbent having the shape and dimensions such as the bead shape of the mesh, and the relationship between the pressure loss and the mass transfer coefficient. It was concluded that the optimum value can be optimized in terms of the basic unit by using the adsorbent of No. 1, and further, the conclusion is not related to the process, and the optimum empty cylinder velocity was obtained and selected. The relationship between the shape and size of the adsorbent and the cylinder velocity is derived, and the diameter of the adsorption cylinder is determined based on the above relational expression to separate the oxygen gas from the air by the PSA method. PSA performance in device for a can be of more conventional.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a system diagram showing a PSA device which is the object of the above simulation. Although the two-cylinder PSA device is shown here, it is needless to say that the present invention is not limited to this.

The two-cylinder PSA apparatus shown in FIG. 1 comprises a raw material air blower 11, two adsorption cylinders 12a and 12b, a surge tank 13, a vacuum pump 14, adsorbents filled in the adsorption cylinders 12a and 12b, and related pipes. (Including a valve) and a control device. Briefly describing the flow of air, the air in the atmosphere is 5
00-5000mmAq (4900-49030Pa)
After being pressurized up to one of the adsorption cylinders 12a and 12b,
For example, it is introduced into the adsorption cylinder 12a. In the adsorption cylinder 12a,
Impurities such as water and nitrogen gas are adsorbed by the adsorbent, and oxygen gas that is difficult to adsorb is led out from the top of the adsorption column 12a. The derived oxygen gas is sent to the surge tank 13, a part of which is discharged as a product, and the remaining part is used for gas purging of the other adsorbing cylinder 12b being regenerated and charging of the regenerated adsorbing cylinder 12b. It On the other hand, the gas adsorbed by the adsorbent is desorbed by depressurizing the inside of the adsorption column by the vacuum pump 14, and thereby the adsorbent is regenerated.
Exhaust gas is discharged from the vacuum pump 14.

An example of the PSA process in this apparatus is shown in FIG. The PSA process is not limited to this, and various processes can be used. The process of FIG. 2 as a typical example will be described.
SA process is (a) charging / product recovery process, (b)
It comprises a pressure equalizing step, (c) vacuum regeneration step, (d) purge regeneration step, and (e) pressure equalization step. Each process will be described by focusing on one of the two towers and the adsorption cylinder 12a.

(A) In the charging / product collecting step, the raw material air supplied from the raw material air blower 11 is introduced from the lower part of the adsorption column 12a and rises in the adsorption column 12a, and water as an impurity during this period, Carbon dioxide gas and nitrogen are adsorbed and removed, oxygen gas is led out from the top of the adsorption column 12a, and is collected as a product through the surge tank 13.

(B) In the pressure equalizing step, the introduction of the raw material air into the adsorption cylinder 12a and the removal of the product from the adsorption cylinder 12a are temporarily stopped. Then, the gas in the adsorption cylinder 12a is
From the upper and lower parts of the suction cylinder 12a, they are simultaneously guided to another suction cylinder 12b.

(C) In the vacuum regeneration step, the adsorption cylinder 12a
The gas in the cylinder is guided to the vacuum pump 14 from the bottom of the column to regenerate the adsorption cylinder 12a under reduced pressure.

(D) In the purge regeneration step, when the vacuum regeneration step reaches a predetermined degree of vacuum, the surge tank 13
A part of the oxygen collected from the above is introduced from the top of the adsorption column 12a, and the pressure reduction by the vacuum pump 14 is continued.

(E) In the pressure equalizing step, when the purge regeneration is completed, the gas flow is reversed from that in the pressure equalizing step (b), and the gas from the other adsorption cylinder 12b is supplied to the top of the adsorption cylinder 12a. Accept from the bottom. Then, when the pressure of the adsorption cylinder 12a rises to a predetermined equalization end pressure, the process returns to the adsorption step (a), the raw material air is introduced from the bottom of the adsorption cylinder 12a, and the adsorption cylinder 12a is pressurized, When a predetermined pressure is reached, the product starts to be discharged from the top of the adsorption cylinder 12a to the surge tank 13.

The product oxygen gas can be continuously sampled by alternately repeating the above steps for both adsorption cylinders 12a and 12b. Further, although the switching condition of each process is described with the pressure as the condition in the above description, the time may be used as the condition.

In carrying out this simulation, the adsorption cylinders 12a and 12b are made of activated alumina for adsorbing water on the feed air inflow end side and X-type on the downstream side for highly adsorbing Li ions as nitrogen adsorption / separation zeolite. It was assumed that each was filled. The packed volume of each adsorbent was about 0.4 m3 for activated alumina and about 2.2 m3 for zeolite, and was constant in each calculation. Other PSAs
The operating conditions of are shown below.

Cycle time 82 seconds Charging / product recovery process 37 seconds Pressure equalization process 4 seconds Vacuum regeneration process 27 seconds Purge regeneration process 10 seconds Pressure equalization process 4 seconds Raw material air temperature 300K Product purity 93.0% Purge gas flow rate 160 Nm3 / h

The parameters used in the calculation are shown below. As the accuracy of the calculation, the calculation grid uses an equidistant grid with a grid length of 0.01 m, and the time interval is 0.1 sec.
Time integration was performed at c.

Raw air composition Water vapor 0.5% Nitrogen 77.7% Oxygen 20.9% Argon 0.9% Heat transfer coefficient between wall-filling layer 1.0W / (m2 ・ K)                   (Activated alumina) (Zeolite)     Filling amount 320kg 1400kg     Packing density 784 kg / m3 644 kg / m3     Porosity 0.4 0.37     Heat capacity 1050 J / (kg ・ K) 920 J / (kg ・ K)

Also, the PSA operation was set to about 2000 cycles until it reached a steady state, and the apparatus performance in the steady state was taken as a simulation result.

First, the equivalent diameter a of the adsorbent particles is 0.6 m.
For three types of m, 1.0 mm, and 1.6 mm, the change in the electric power consumption rate when the hollow velocity of the raw material air was changed was obtained. Thus, for each particle size, there is an optimum flow velocity that minimizes the power consumption. From the obtained results, the ratio of the electric power consumption rate is calculated with reference to the value showing the minimum electric power consumption rate when the equivalent diameter a is 1.0 mm, and it is shown in FIG. Shown in.

Next, from FIG. 3, the particle equivalent diameter a and the hollow velocity u of the raw material air for which the power consumption rate is the minimum at each particle equivalent diameter a are determined, and the particle equivalent diameter a of the adsorbent and the power are calculated. The relationship with the empty cylinder velocity u of the raw material air having the minimum unit consumption was calculated. The result is shown in FIG.

From FIG. 4, it can be seen that the relationship between the equivalent diameter a of the adsorbent and the empty velocity u of the raw material air that minimizes the electric power consumption can be approximated by a straight line and is expressed by the following equation.
u = 0.07a + 0.095

Further, from FIG. 3, in order to keep the ratio of the electric power consumption rate to the particle equivalent diameter a to within about 3% as the allowable increase range from the minimum value of the electric power consumption rate, the designed empty cylinder speed U The lower limit is 0.75u ≦ U ≦ 1.25u.

As can be seen from these results, there is an optimum feed air void velocity depending on the equivalent diameter a of the adsorbent particles. Further, FIG. 5 shows a relationship between the point where the minimum value is obtained as the electric power consumption rate and the equivalent diameter a of the adsorbent particles.

As is clear from FIG. 5, when the equivalent diameter a of the adsorbent particles is 1 mm, the electric power consumption rate of the oxygen PSA device shows the minimum value.

Here, the shape of the adsorbent particles that are generally commercially available, particularly the adsorbent in the form of beads, has a particle size distribution and is a mixture of large and small particle sizes. In an apparatus in which the particle size of the adsorbent is a problem, it is sold by sieving so that the particle size distribution has a peak value at a specific particle size.

In the present invention, the power unit consumption of the PSA device is minimized by using an adsorbent having a specific equivalent diameter (including the diameter) as the adsorbent for the PSA device. It is desirable that the peak of the distribution be within a specific value range.

The particle size distribution of the adsorbent is measured by using a sieve such as a Tyler standard sieve, and the range of particles from 14 mesh to 16 mesh and above is generally 1 mm depending on the size of the sieve used. Will have a diameter of. Generally, if the particle size is selected within such a narrow range, the amount that can be sold as a product will be reduced, so the size of the particles within a certain range (for example,% by weight) can be kept constant by giving the sieve a certain width. It is done to be more than the ratio.

The adsorbent used in the present invention is 1 mm
It is preferable that particles having 12 mesh or less and 20 mesh or more occupy 70% or more of the whole by weight% before and after that. Higher percentages are still desirable, but lower percentages, that is, relatively large numbers of larger or smaller particles, are expected as the performance of the resulting PSA device. Therefore, the minimum value of power consumption per unit will not be obtained.

When the mesh size of the above-mentioned sieve is expressed as a numerical value, 20 mesh is 0.833 mm and 12 mesh is 1.397 mm.
0.2 mm will be allowed. Taking the above-mentioned particle size distribution, it can be said that the equivalent diameter or the amount having a diameter in the range of 1 ± 0.2 mm is at least 70% of the total amount of the adsorbent.

[0057]

As described above, according to the present invention,
The power consumption of the oxygen PSA device can be minimized. In addition, the performance of the oxygen PSA device can be improved by forming the adsorption cylinder so as to establish a specific relationship with the adsorbent.

[Brief description of drawings]

FIG. 1 is a system diagram showing an oxygen PSA apparatus which is a simulation target.

FIG. 2 is a diagram showing an example of an oxygen PSA process.

FIG. 3 is a diagram showing a relationship between a blank speed of raw material air and a ratio of electric power consumption rate.

FIG. 4 is a diagram showing a relationship between a particle equivalent diameter and a void velocity of raw material air having a minimum electric power consumption rate.

FIG. 5 is a diagram showing a relationship between a point at which a minimum value is obtained as a power consumption unit and an equivalent diameter of adsorbent particles.

[Explanation of symbols]

11 ... Raw material air blower, 12a, 12b ... Adsorption cylinder, 1
3 ... surge tank, 14 ... vacuum pump

Continued front page    F-term (reference) 4D012 BA02 CA05 CB16 CD07 CF02                       CF10 CG01 CG05                 4G066 AA61B AA62B BA20 CA27                       CA43 DA03 GA14

Claims (6)

[Claims] 1. An adsorption column filled with an adsorbent for separating and collecting oxygen in air by a pressure swing adsorption separation method, wherein the size of the adsorbent is the diameter when the adsorbent is spherical, and the adsorbent is When the equivalent diameter is set to a [mm] in the case of a cylindrical shape, an elliptic shape, or an elliptic shape, the empty cylinder velocity u [m /
[s] is set to be in the range of ± 25% of u = 0.07a + 0.095, the adsorption cylinder for pressure fluctuation adsorption separation. 2. The adsorbent has a particle size distribution of 12 when measured with a Tyler standard sieve.
The adsorption column for pressure fluctuation adsorption separation according to claim 1, wherein the adsorbent particles in the range of mesh to 20 mesh are contained at least 70% or more. 3. The adsorption cylinder for pressure fluctuation adsorption separation according to claim 1, wherein the adsorbent has a diameter or equivalent diameter a of the adsorbent in the range of 1.0 ± 0.2 mm. 4. The adsorbent is a Ca-A type zeolite,
Alternatively, the pressure fluctuation adsorption separation according to claim 1, which is one of Na-X type and zeolite in which at least a part of Na of the Na-X type is ion-exchanged with Ca, Mg, Li. Adsorption cylinder. 5. The adsorption cylinder for pressure fluctuation adsorption separation according to claim 1, wherein the pressure fluctuation adsorption separation method is a pressure fluctuation adsorption separation method for performing vacuum regeneration. 6. A pressure fluctuation adsorption / separation apparatus comprising the adsorption cylinder according to claim 1. Description: