JP2002310877A - Adsorption rate measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for easily measuring a parameter to be used as an index of a gas adsorption rate in adsorbent. SOLUTION: The adsorption rate measuring device is provided with a pressure vessel with adsorbent having an adsorbent housing means housing the adsorbent in an interior, a pressure producing means applying pressure by measuring object gas to the pressure vessel with adsorbent, and a pressure feeding means feeding the measuring object gas pressure produced by the pressure producing means to the pressure vessel with adsorbent. It is characterized by that it is provided with a gas flow rate measuring means measuring a time series change of flow rate of the measurement object gas flowing between the pressure vessel with adsorbent and the pressure producing means, and a calculating means calculating the adsorption rate of the adsorbent from the gas flow rate measured by the gas flow rate measuring means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adsorption speed measuring device for measuring a gas adsorption speed of an adsorbent for adsorbing gas. More specifically, the present invention relates to an apparatus for measuring a temporal change of a gas integrated adsorption amount due to a pressure change.

[0002]

2. Description of the Related Art As a method for measuring the adsorption speed of an adsorbent for adsorbing a gas, there are known a constant pressure capacity method, a flow-type weight method, an adsorption breakthrough curve method, and the like. -Design-NTS Inc.).

[0003] In the constant pressure capacity method, the pressure, volume and temperature of an adsorbed gas before and after adsorption are measured, and the amount of adsorption is determined from the difference in the number of moles of the adsorbed gas present in the adsorbent. In the actual measurement of the amount of adsorption, the temperature and pressure are kept constant, and the temporal change in the volume is obtained.

The flow-type weight method is a method in which a gas is flowed outside an adsorbent sample while keeping the pressure and concentration constant, and the amount of adsorption is directly measured from an increase in the weight of the adsorbent.

[0005] The adsorption breakthrough curve method is a method of measuring the time-series gas concentration at the outlet of the adsorption layer and obtaining the effective diffusion coefficient in particles from the type of the concentration curve.

[0006]

As described above, there are methods for measuring the adsorption of various gases to an adsorbent, but each has a drawback. That is, the constant pressure capacity method has a disadvantage that the pressure and the dead volume around the adsorbent must be accurately measured. On the other hand, the flow-type gravimetric method has a problem that it is difficult to measure the total pressure at a pressure other than the atmospheric pressure, and that a measurement error is generally large. Further, in the adsorption breakthrough curve method, it is necessary to measure the gas concentration at a time interval as short as possible, and the measurement requires a device.

[0007]

Means for Solving the Problems In order to achieve the above object, the present inventors have made intensive studies and as a result, arranged the adsorbent in layers, intentionally changed the pressure of chambers provided above and below the adsorbent, and changed the pressure to the chamber. By measuring the time-series change of the gas inflow amount, it was found that the gas adsorption speed of the adsorbent due to the pressure change can be measured inexpensively and easily.

That is, the present invention provides an adsorbent-containing pressure vessel provided with adsorbent storage means for storing an adsorbent, a pressure generating means for applying pressure to the adsorbent-containing pressure vessel by a gas to be measured, Gas flow rate measuring means for measuring a flow rate of a gas to be measured flowing between the adsorbent-containing pressure vessel and the pressure generating means, comprising a pressure supply means for supplying pressure generated by the generating means to the adsorbent-containing pressure vessel, It is an object of the present invention to provide an adsorption speed measuring apparatus, comprising an arithmetic means for calculating an adsorption speed of the adsorbent from a time-series change of a gas flow rate measured by the gas flow rate measuring means.

In the present invention, the adsorbent storage means can arrange the adsorbents in layers, and has adsorbent temperature measuring means for measuring the temperature of the adsorbent. Such an adsorbent-containing pressure vessel has spaces of equal volume above and below the adsorbent storage means, and the pressure supply means includes pressure adjusting means for adjusting the pressure generated by the pressure generating means to an arbitrary pressure. .

The pressure arbitrarily adjusted by the pressure adjusting means is stored in the gas supply tank to be measured, and the solenoid valve for pressure supply which has been closed is opened by a switch to raise and lower the pressure vessel with the adsorbent. The pressure of the provided chamber is intentionally changed.

The arithmetic means includes an adsorbent in the adsorbent accommodating means, which is measured by the gas flow rate measuring means when a pressure in a chamber provided above and below the adsorbent-containing pressure vessel is intentionally changed. The time-series gas flow rate 1 in the case and the time-series gas flow rate 2 when the adsorbent is not present in the adsorbent storage means are stored, and the integration calculation of the difference between the time-series gas flow rate 1 and the time-series gas flow rate 2 is performed. It is characterized by including a function to perform.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, an adsorption rate measuring apparatus according to the present invention comprises an adsorbent pressure vessel (1) provided with adsorbent storage means for storing an adsorbent; A pressure generating means (2) for applying pressure to the container by the gas to be measured; and a pressure supply means (3) for supplying the pressure generated by the pressure generating means to the pressure vessel containing the adsorbent. Gas flow measuring means (4) for measuring the flow rate of the gas to be measured flowing between the container and the pressure generating means, and calculating means (calculating the adsorption rate of the adsorbent from the gas flow rate measured by the gas flow measuring means ( 5).

As shown in FIG. 2, the adsorbent-containing pressure vessel (1) is configured such that an adsorbent storage means (1b) for storing the adsorbent (1a) divides the volume inside the container into two equal parts. Are located. The adsorbent storage means (1b) generally has a structure in which a granular adsorbent is sandwiched by a structure that does not transmit an adsorbent such as a mesh structure or a nonwoven fabric but can easily transmit pressure. It is characterized in that the adsorbent (1a) can be arranged in layers by this structure. The adsorbent storage means (1b) serves as an adsorbent temperature measuring means (1c) for measuring the temperature of the adsorbent.
A temperature detection sensor such as a thermocouple or a thermistor having a relatively fast response speed is attached.

The adsorbent-filled pressure vessel (1) may be any as long as it has sufficient mechanical strength to withstand the pressure to be actually measured, and is desirably made of stainless steel and has an inner surface having a surface property such as an electrolytic polishing method. It is preferable to improve the gas fluidity by performing enhanced processing. The pressure generating means (2) may be any as long as a desired pressure to be measured can be given to the gas to be measured with a margin, and examples thereof include a pressure cylinder, a compressor having an oil-free structure, and a vacuum pump having an oil-free structure. .

The pressure supply means (3) is located between the adsorbent-containing pressure vessel (1) and the pressure generation means (2), and adjusts the pressure generated by the pressure generation means (2) to an arbitrary pressure. A pressure adjusting means is provided. As a preferred specific method of the pressure adjusting means, as shown in FIG. 3, a pressure adjusting valve (3a) having a function of keeping the pressure on the secondary side constant, and a sufficient measurement object for a sudden pressure change A tank (3b) for supplying a gas to be measured for supplying gas to the pressure vessel containing the adsorbent, and a solenoid valve (3) for supplying pressure to cause a sudden change in pressure.
c) and a switch (3d) as an operation unit for opening and closing the pressure supply solenoid valve. The pressure arbitrarily adjusted by the pressure adjusting means is stored in the gas supply tank to be measured, and the closed pressure supply solenoid valve (3c) is opened by the switch (3d) to open the pressure vessel containing the adsorbent. The pressures of the chambers provided above and below are intentionally changed. The gas flow rate measuring means (4) measures the flow rate of the gas to be measured when the pressures of chambers provided above and below the adsorbent-containing pressure vessel (1) are intentionally changed. It has a function to output the measured flow rate from time to time using an electric signal, etc.,
It is preferable that the pressure loss in the gas flow path is small and the measurement accuracy is high, such as a mass flow meter.

The arithmetic means (5) comprises a time-series gas flow rate 1 when the adsorbent is present in the adsorbent storage means (1b), measured by the gas flow rate measurement means (4), and an adsorbent storage means (1b). Time-series gas flow rate 2 when no adsorbent is present
Is stored in a data storage medium such as a memory, and the time when each of the pressure supply solenoid valves (3c) is opened is set to 0, and the time-series gas flow rate 1 and It has a function of performing an integration calculation of the difference from the time-series gas flow rate 2. With the function of performing such calculations,
A personal computer, a DSP or the like is desirable. As a result of the calculation, the time-series adsorption amount data of the gas to be measured by the adsorbent is calculated, and the time-series adsorption amount data and the adsorption speed time constant / saturated adsorption amount can be calculated from the time-series adsorption amount data.

[0017]

EXAMPLES The adsorption rate of zeolite was measured using nitrogen as the gas to be measured. As the adsorbent-containing pressure vessel, a stainless steel pressure vessel having an inner diameter of 100 mm and a height of 50 mm was used. Gas supply holes are formed in the upper and lower surfaces of the pressure vessel, so that a measurement gas is supplied from the pressure supply means. Further, two nonwoven fabrics can be fixed as an adsorbent storage means in the center of the inside of the pressure vessel, and granular zeolite is spread in layers between the nonwoven fabrics. Further, the tip of a K-type thermocouple was brought into contact with the granular zeolite to measure the temperature of the adsorbent.

As the gas supply tank to be measured, a pressure vessel having a volume sufficiently larger than the volume of the pressure vessel containing the adsorbent was prepared. As the gas flow rate measuring means, a mass flow meter is used, and the instantaneous value of the gas flow rate measured by the mass flow meter is transmitted to a personal computer, which is an arithmetic means, for about 1 hour.
It was sent every 0 msec.

Before the measurement is started, the inside of the pressure vessel containing the adsorbent is replaced with nitrogen gas and kept at 0.0 MPaG. The pressure supply solenoid valve was closed in advance, and the secondary pressure was adjusted to 0.1 MPaG by a pressure adjustment valve attached to the nitrogen cylinder used as the pressure generating means.
By opening the pressure supply solenoid valve, the pressure inside the adsorbent-containing pressure vessel is increased almost instantaneously to 0.1 MPaG.

FIG. 4 shows an example of measurement data measured by this apparatus. The time-series gas flow rate 1 is the output of the mass flow meter when the adsorbent is filled between the two nonwoven fabrics serving as the adsorbent storage means, and the time-series gas flow rate 2 is the adsorbent storage means 2
4 shows the output of a mass flow meter when the adsorbent is not filled between two nonwoven fabrics. In addition, time-series data obtained by integrating the flow rate obtained by subtracting the time-series gas flow rate 2 from the time-series gas flow rate 1 at each time is shown as an integrated adsorption amount. The accumulated amount of adsorption is from 0.0 MPa to 0.
It can be used as one of the indexes indicating the adsorption speed when the pressure changes to 1 MPa.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an adsorption speed measuring device.

FIG. 2 is an explanatory view of an adsorbent-containing pressure vessel.

FIG. 3 is an explanatory diagram of a pressure adjusting unit.

FIG. 4 shows a preferred embodiment of the adsorption rate measuring device of the present invention.

[Explanation of symbols]

 (1) Adsorbent-filled pressure vessel (1a) Adsorbent (1b) Adsorbent storage means (1c) Temperature detection means (2) Pressure generation means (3) Pressure adjustment means (3a) Pressure adjustment valve (3b) Gas to be measured Supply tank (3c) Solenoid valve for pressure supply (3d) Switch (4) Gas flow measurement means (5) Calculation means

Claims (5)

[Claims] 1. An adsorbent-filled pressure vessel having an adsorbent storage means for storing an adsorbent therein, a pressure generating means for applying a pressure of a gas to be measured to the adsorbent-containing pressure vessel, and a measurement generated by the pressure generating means. A gas supply unit for supplying a target gas pressure to the adsorbent-containing pressure vessel, and a gas flow rate for measuring a time-series change in a flow rate of a measurement target gas flowing between the adsorbent-containing pressure container and the pressure generating means; An adsorption speed measuring device comprising: a measuring means; and a calculating means for calculating an adsorption speed of the adsorbent from a gas flow rate measured by the gas flow rate measuring means. 2. The adsorbent storage means according to claim 1, wherein said adsorbent storage means is means for arranging the adsorbent in a layered form, and has adsorbent temperature measuring means for measuring the temperature of said adsorbent. Adsorption rate measuring device. 3. The adsorbent storage means is positioned in the middle of the adsorbent-containing pressure vessel so as to have a space of equal volume up and down,
3. The adsorption velocity measuring device according to claim 1, further comprising an in-vessel temperature measuring means for measuring a temperature in the space. 4. The adsorption speed measuring apparatus according to claim 1, wherein said pressure supply means includes a pressure adjusting means for adjusting the pressure generated by said pressure generating means to an arbitrary pressure. 5. The time-series gas flow rate 1 when the adsorbent is present in the adsorbent storage means measured by the gas flow rate measurement means and the time when the adsorbent is not present in the adsorbent storage means. A function of storing the series gas flow 2 and the time series gas flow 1
5. The adsorption velocity measuring apparatus according to claim 1, further comprising a function of performing an integration operation of a difference between the flow rate and the time-series gas flow rate 2.