JP2001279267A - Method for producing industrial gas by using pressure- varied adsorptive separation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an industrial gas by using PSA apparatus, capable of more correctly controlling load of PSA apparatus, following used amount of gas of a gas user. SOLUTION: In this method for producing an industrial gas by using PSA apparatus, pressure fluctuation in a product gas holclet is measured and pressure (Pn) after correction of average value of variation of the product gas holder is obtained based on the measured value and apparatus load on PSA apparatus is obtained based on pressure after correction of average value of variation and preceding variation of apparatus load on PSA apparatus is obtained based on measured value of pressure fluctuation of the product gas holder and weight coefficient in operation of apparatus load and preceding variation of the apparatus load is added to the apparatus load obtained based on the pressure (Pn) after correction of average value of variation to provide preceding apparatus load, and introduction amount of raw material gas to the PSA apparatus and required time of each step are controlled based on the preceding apparatus load.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing industrial gas using a pressure fluctuation adsorption / separation apparatus, and more particularly to predicting fluctuations in gas usage in a gas destination apparatus, and performing pressure fluctuation based on the predicted amount. The present invention relates to an industrial gas production method using a pressure-fluctuation adsorption / separation device capable of preliminarily controlling the device load of the adsorption / separation device.

[0002]

2. Description of the Related Art Hydrogen, for example, as an industrial gas, is obtained by steam reforming hydrocarbons such as city gas, LPG and naphtha in the presence of, for example, a nickel-based reforming catalyst, and reforming hydrogen-rich gas. A pressure fluctuation adsorption separation device (hereinafter also referred to as a PSA device) having a plurality of adsorption columns filled with an adsorbent that selectively adsorbs a gas under a high pressure and a desorber under a reduced pressure, for example, a component other than hydrogen. It is manufactured by introducing into the adsorption tower and sequentially repeating processing steps such as an adsorption step, a decompression step, a blowdown step, a purge step, and a pressure increase step, and the purity thereof is, for example, 99.999 vol.
% Or more.

FIG. 6 is a diagram showing a system of a hydrogen production apparatus using a PSA apparatus having a raw material reforming apparatus. In this figure, this hydrogen production apparatus separates a high-purity hydrogen using a raw material reforming device 62 for reforming a reforming raw material 61 and a hydrogen-rich reformed gas 63 generated in the raw material reforming device 62 as a raw material gas. The PSA device 64 is roughly divided into a PSA device 64 to be collected,
Reference numeral 4 denotes an adsorbent mainly composed of, for example, adsorption towers A, B and C filled with zeolite, pipes connecting these adsorption towers, valves and the like provided in the pipes. Reference numeral 65 denotes a product gas holder for storing hydrogen as the product gas 66.

[0004] Reforming raw material 6 such as city gas, LPG, naphtha, etc.
1 is desulfurized by a known method if necessary,
The reformed gas is introduced into the raw material reforming device 62 and, in the presence of, for example, a nickel-based reforming catalyst, comes into contact with steam 67 in a high temperature range of about 800 ° C., and becomes a reformed gas 63 having a high hydrogen concentration by a steam reforming reaction. The reformed gas 63 flows into the adsorption tower A of the downstream PSA device 64 and, for example, adsorbs, decompresses, blows down,
Hydrogen is separated through purging and pressurizing steps, and is stored as product gas 66 in product gas holder 65. Adsorption tower B
The same pressure fluctuation adsorption / separation operation is sequentially performed also in steps C and C, and high-concentration hydrogen is temporarily stored in the product gas holder 65, and then supplied as a product gas 66 to a gas use device (not shown). 68 and 69 are fuel and combustion air supplied to the reformer 62, respectively, and 70 is
Off-gas discharged from the PSA device 64.

[0005] In such an industrial gas production method using a PSA device, it is important to control the load on the device in accordance with the fluctuation of the gas consumption in the device where the product gas is used.
Conventionally, a method has been adopted in which the pressure in the delivery gas (product gas) holder is actually measured, and the apparatus load is directly determined based on the fluctuation of the pressure. FIG. 7 is an explanatory diagram showing the relationship between the hydrogen holder pressure and the load on the PSA device in such a conventional hydrogen production method using a PSA device. In the figure, it can be seen that the apparatus load of the PSA is directly controlled based on the actual measured value of the hydrogen holder pressure, and therefore greatly fluctuates in accordance with the holder pressure.

That is, the industrial gas production method using the PSA apparatus has the characteristic that the amount of generated gas, in other words, the pressure in the product gas holder, fluctuates according to a certain waveform based on each process cycle. In the above-described conventional technology in which the device load is directly controlled based on the pressure fluctuation of a product gas holder (hereinafter, also simply referred to as a holder), even if the pressure fluctuation of the product gas becomes a disturbance element and the gas usage amount of the used device is constant. Regardless, there is a drawback that the load of the gas production apparatus fluctuates greatly. For this reason, it has been difficult to produce a required amount of product gas by following a change in the gas usage of the gas usage destination device. In order to solve such a problem, in recent years, for example, a method of increasing the capacity of a product gas holder, absorbing a pressure fluctuation of a PSA device by the capacity of the product gas holder, measuring a gas usage amount of a use destination, and measuring the gas usage amount. A method of calculating the load of the PSA device based on the above, a method of absorbing the disturbance element by delaying the response of the device load and performing moving average, etc. have been adopted.

[0007]

However, such a conventional technique leads to an increase in the size of the apparatus and a rise in equipment costs, and its load following ability has never been satisfactory. Therefore, there has been a demand for the development of an industrial gas production method using a PSA device that can more accurately control the load of the PSA device in accordance with the amount of gas used in the gas destination device. An object of the present invention is to solve the above-mentioned problems of the prior art, eliminate the control disturbance of the PSA device, and significantly improve the ability of the device load to follow a change in the gas usage of the gas destination device. An object of the present invention is to provide an industrial gas production method using a PSA device, which can reduce the size of the device and reduce equipment costs.

[0008]

In order to solve the above-mentioned problems, the present inventor has proposed a method for measuring the fluctuation of the gas usage in a gas use destination device connected to a product gas holder, the pressure in the gas holder of the PSA device, the fluctuation of the device load, and the like. As a result of diligent research on the relationship, the pressure fluctuation in the product gas holder of a PSA device filled with an adsorbent and having at least three adsorption towers was measured, and the average value of the variation of the product gas holder was corrected based on the measured value. The pressure (P _n ) after the change is obtained, the device load of the PSA device corresponding to the obtained pressure after the correction of the average value of the change amount is obtained, and the measured value of the pressure fluctuation in the product gas holder and the weight coefficient at the time of the device load calculation are calculated. Based on P
A preceding fluctuation amount of the device load of the SA device is obtained, and the preceding device load fluctuation amount is added to the device load obtained based on the pressure (P _n ) after the correction of the average value of the change amount, thereby obtaining a preceding device load. By controlling the amount of source gas introduced into the PSA device and the time required for each process based on the device load, the product gas can be controlled in accordance with the gas usage of the gas destination device connected to the product gas holder of the PSA device. They found that they could be manufactured and supplied and arrived at the present invention.

That is, the invention claimed in the present application is as follows. (1) A raw material gas is introduced into a pressure fluctuation adsorption separation (PSA) apparatus having at least three adsorption towers filled with an adsorbent, and the easily adsorbable components in the raw material gas are converted into adsorbents in the respective adsorption towers. An adsorption step of separating and recovering the hardly adsorbable components by adsorption, a pressure reduction step of depressurizing the adsorption tower after the adsorption step and using an off-gas flowing out of the adsorption tower as a purge gas of another adsorption tower, and a pressure reduction step. A blowdown step of collecting the off-gas released from the adsorbent by further reducing the pressure of the completed adsorption tower, and an adsorption tower after the blowdown step has been completed,
It has a purging step of introducing off gas flowing out of the adsorption tower during the pressure reducing step of another adsorption tower to purge the inside of the tower, and a pressure increasing step of introducing product gas to the adsorption tower after the purging step and increasing the pressure. A series of pressure fluctuation adsorption / separation operations are sequentially repeated at predetermined intervals to collect a specific component in the raw material gas, and send it to a device where the gas is to be used via a product gas holder. In the manufacturing method, a pressure fluctuation in the product gas holder is measured, a pressure (P _n ) of the product gas holder after the correction of the average of the change is determined based on the measured value, and the pressure (P _n ) is corrected based on the pressure after the correction of the average of the change. The apparatus load of the pressure fluctuation adsorption / separation apparatus is obtained, and the pressure fluctuation adsorption / separation apparatus is determined based on the measured value of the pressure fluctuation of the product gas holder and the weight coefficient at the time of the apparatus load calculation. Calculated prior variation of the device load, the device loads the preceding variation to the preceding device load in addition to the device load calculated based on the pressure (P _n) after the variation average value correction, said prior apparatus a load Controlling the amount of the raw material gas introduced into the pressure fluctuation adsorption / separation apparatus and the time required for each of the steps on the basis of the pressure fluctuation adsorption / separation apparatus.

(2) Between the pressure reducing step and the blow-down step, a pressure equalizing step in which the adsorption tower in which the pressure reducing step has been completed communicates with the other adsorption tower in which the purging step has been completed to equalize the pressure in the tower. Between the purge step and the pressure increase step,
(1) The pressure fluctuation adsorption according to the above (1), further comprising a pressure equalizing step of connecting the adsorption tower after the purging step and another adsorption tower after the depressurizing step to equalize the pressure in the tower. Industrial gas production method using a separation device. (3) The raw material gas is a hydrogen-containing gas, and a component recovered from the raw material gas is hydrogen.
Or the industrial gas production method using the pressure fluctuation adsorption separation device according to (2).

(4) A raw material gas is introduced into a pressure swing adsorption / separation (PSA) apparatus having at least first, second and third adsorption towers filled with an adsorbent.
An adsorption step in which the easily adsorbable components in the raw material gas are adsorbed by the adsorbent to separate and recover the hardly adsorbable components; and an off-gas flowing out of the adsorption tower is decompressed by depressurizing the adsorption tower after the adsorption step. A pressure reduction step used as a purge gas for the column, a pressure equalization step of communicating the adsorption tower after the pressure reduction step with the other adsorption tower after the purge step to equalize the pressure in the tower, and the pressure equalization step. A blowdown step of collecting the offgas released from the adsorbent by further reducing the pressure of the adsorption tower, and introducing the offgas flowing out of the adsorption tower during the pressure reduction step of another adsorption tower to the adsorption tower after the blowdown step has been completed. A purging step of purging the inside of the tower by pressure, a pressure equalizing step of communicating the adsorption tower after the purging step with another adsorption tower after the depressurizing step to equalize the pressure in the tower, and a pressure equalizing step. Finished adsorption tower A series of pressure fluctuation adsorption / separation operations having a pressure increasing step of introducing and increasing the pressure of a gas are sequentially repeated at predetermined intervals to collect a specific component in the raw material gas and send it to a device where the gas is used via a product gas holder. In the industrial gas production method using the pressure fluctuation adsorption / separation apparatus, the pressure of the product gas holder is measured, and the average pressure (P _1a ) of the product gas holder during the pressure reduction step of the second adsorption tower and the third adsorption tower are measured. Average pressure (P
_1b) the average value of (the P _n-2), the average value of the average pressure during depressurization step of the first adsorption tower (P _2a) and the average pressure during boosting step of the second adsorption tower (P _2b) ( P _n-1 ) and the following formula (1)
To obtain the product gas holder pressure (P _n ) after the correction of the average value of the variation, and P _n (MPa) = [(P _n−2 ) + (P _n−1 )] / 2 (1) Based on the product gas holder pressure (P _n ) after the average value correction, the device load (Y _n ) of the pressure fluctuation adsorption separation device is obtained by the following equation (2), and Y _n (%) = A · P _n + B ··· (2) (where A and B are coefficients of a first-order approximation formula for obtaining an apparatus load from a product gas holder pressure value, and A is
The gain, B, is the bias. Then, the average value (P _n−2 ) of the average pressure of the product gas holder and (P _n−2 )
_n-1 ) based on the difference ( _{Pn-2- Pn-1} ) and the weighting coefficient (K) at the time of calculating the device load, the following equation (3) is used to calculate the preceding fluctuation amount of the device load of the pressure fluctuation adsorption / separation device. (Z _n ) is predicted, and Z _n = (P _n−2 −P _n−1 ) · K (3) (K = weight coefficient) The predicted device load preceding fluctuation amount (Z _n ) by the following equation (4), a device load amount determined on the basis of the holder pressure after the variation average value correction (Y _n) in addition to the preceding device load _{(X n), X n =} Y n + Z n ·· (4) Hereinafter, the same operation is sequentially repeated to obtain the preceding apparatus load, and based on the obtained preceding apparatus load (X _n ), the amount of the raw material gas introduced into the pressure fluctuation adsorption / separation apparatus and the above-mentioned respective values in each adsorption tower. An industrial gas production method using a pressure-fluctuation adsorption / separation apparatus, characterized by controlling the time required for a treatment step.

(5) The industrial gas production using a pressure fluctuation adsorption separation apparatus as described in (4) above, wherein the raw material gas is a hydrogen-containing gas, and a component recovered from the raw material gas is hydrogen. Method.

In the present invention, the pressure after the correction of the average value of the variation of the product gas holder is defined as the average value of the average pressures in the two holders in the unit process and the average value of the pressure in another unit process following the unit process. The average value of the average pressure in two holders is further averaged, and the pressure fluctuation in the holder due to the unique characteristics of the PSA device that repeats the adsorption step, depressurization step, blowdown step, purge step, pressure increase step, etc. sequentially Means the actual pressure in the holder corrected for The pressure after correcting the change amount average value of the product gas holder is an index for calculating the gas usage amount of the usage destination device since the product gas holder is connected to the product gas usage destination device. In the present invention, the weight coefficient (K) at the time of calculating the device load is PS
This value is corrected by the advance control rate (feed forward gain), which is a threshold for fluctuations in the rated load of the A device, the product gas holder capacity, and the gas usage amount of the gas destination device, and is an optimal value depending on the actual device operation state. Is a tuning parameter for calculating 1.0.
A constant in the range of 5 is used.

In the present invention, the preceding fluctuation amount of the apparatus load is defined as the average value of the average pressures in the two holders in a unit process and the average value of the average pressure in another unit process following the unit process.
The predicted fluctuation amount of the device load is expressed as a product obtained by multiplying the difference between the two average values of the average pressure in the holder by the weight coefficient (K) at the time of calculating the device load. By adding the predicted fluctuation amount (preceding fluctuation amount) to the apparatus load corresponding to the pressure in the holder after the correction of the change amount average value, the preceding apparatus load of the entire apparatus is obtained. In the present invention, between the pressure-reducing step and the blow-down step, the pressure-reducing step has a pressure equalizing step to equalize the pressure inside the column by communicating the adsorption tower and the other adsorption tower after the purge step has been completed, Between the purge step and the pressure increase step,
It is preferable to have a pressure equalizing step of making the column pressure equal by connecting the adsorption tower after the purging step and another adsorption tower after the depressurizing step. Thereby, the separation property of each component gas is improved, and the recovery rate of the target component is improved. The time required for the pressure equalizing step and the pressure in the column are appropriately determined by the time in other steps, the pressure in the column, and the like.

In the present invention, the off-gas flowing out of the adsorption tower in the depressurization step can be used for another purpose or discharged out of the system without using it as a purge gas for another adsorption tower. Further, as the purge gas in the purge step, a gas other than the off-gas flowing out of the adsorption tower during the pressure reduction step in another adsorption tower can be used. In the present invention, the target component to be recovered from the raw material gas may be, for example, oxygen, nitrogen, carbon monoxide, or the like, in addition to hydrogen.

[0016]

Next, the present invention will be described in detail by taking, as an example, a method for producing hydrogen using a PSA apparatus, in which a hydrogen-containing gas is used as a raw material gas, and the hydrogen in the hydrogen-containing gas is separated and recovered. Will be described. 1 and 2 are explanatory views showing the principle of the present invention. FIG.
The average pressure in the unit process of the hydrogen holder pressure (hereinafter also referred to as the average change amount) and the device load amount (Y _n ) obtained based on the hydrogen holder pressure (P _n ) after the correction of the average change amount. FIG. 2 is a diagram showing the relationship. FIG. 2 shows the hydrogen holder pressure, the average change amount of the hydrogen holder pressure, and the average value (P _n−2 ) of the two change average values with a time interval. The relationship between the difference (P _n−1 ) of (P _n−1 ) (P _n−2 −P _n−1 ) and the device load preceding variation (Z _n ) obtained based on the weight coefficient (K) at the time of the device load calculation is shown. FIG.

In FIG. 1, a P comprising A, B and C3 towers
In the SA device, a series of pressure-fluctuation adsorption / separation operations including nine steps of a three-step adsorption step and a one-step pressure reduction step, a pressure equalization step, a blowdown step, a purge step, a pressure equalization step, and a pressure increase step are performed. The adsorption towers A, B, C
, The pressure in the hydrogen holder is monitored in a case where the pressure is repeatedly shifted by three steps, and the average value of the change in the hydrogen holder pressure during the decompression step of the tower B: P _1a = (P ₁₁ + P ₁₂ ) /
2 and the average value of the change in the hydrogen holder pressure during the C tower pressure step: P _1b = (P ₁₃ + P ₂₁ ) / 2: P _n−2 =
(P _1a + P _1b ) / 2 corresponds to the adsorption step of the tower A (steps 1 to 5).
3) Average hydrogen holder pressure at time: expressed as P _n-2 .

On the other hand, the average value of the change in the hydrogen holder pressure during the pressure reduction step of the tower A: P _2a = (P ₂₁ + P ₂₂ ) / 2, and the average value of the change in the hydrogen holder pressure during the pressure increase step of the tower B: P _2b = (P ₂₃ +
Average value of P ₃₁ ) / 2: P _n-1 = (P _2a + P _2b ) / 2
The average hydrogen holder pressure during the adsorption step (steps 4 to 6) of the column C is expressed as P _n-1 . Here, the following equation (1)
Pressure in the hydrogen holder (P _n )
P _n (MPa) = (P _n−2 + P _n−1 ) / 2 (1) The obtained pressure in the hydrogen holder (P _n ) after correction of the average value of the variation.
The device load (Y) of the PSA device corresponding to the hydrogen holder internal pressure (P _n ) according to the following linear approximation (2) based on
_n ) can be determined.

Y _n (%) = A · P _n + B (2) (where A and B are coefficients of a first-order approximation formula for obtaining an apparatus load from a product gas holder pressure value, and A is ,
The gain, B, is the bias. 2) In FIG. 2, the pressure in the hydrogen holder, the average value of the change in the pressure in the hydrogen holder, and the average value (P _n−2 ), (P _n−1 ) of the two average values of the change in the predetermined process. Is obtained by multiplying the difference (P _n−2 −P _n−1 ) by the weight coefficient (K) at the time of the device load calculation, and shows the relationship with the preceding fluctuation amount (Z _n ) of the device load predicted by the following equation (3). Have been. Z _n = (P _n−2 −P _n−1 ) · K (3) Determined based on the predicted device load preceding fluctuation (Z _n ) and the holder pressure after the correction of the average of the change. Equipment load (Y
_n ) is the preceding device load (X _n ) of the PSA device.

X _n = Y _n + Z _n (4) Hereinafter, the same operation is repeated to continuously obtain the preceding apparatus load, and the raw material to the PSA apparatus is determined according to the obtained preceding apparatus load (X _n ). By determining and controlling the amount of gas introduced and the set times of the adsorption step, pressure reduction step, pressure equalization step, blowdown step, purge step, pressure equalization step and pressure increase step in each adsorption tower, the pressure in the hydrogen holder is reduced. Even if it fluctuates greatly, it is possible to predict the gas usage of the gas use destination device, produce a product gas, for example, hydrogen in an amount that follows the gas usage amount, and reliably supply it to the use destination device.

In the present invention, the number of adsorption towers is three or more, and preferably an integer multiple of three. The adsorbent varies depending on the target component to be recovered. For example, zeolite, activated carbon, activated alumina and the like are used. In the present invention, the source gas introduced into the PSA apparatus is not particularly limited as long as it is a gas containing the target component. For example, a reformed gas obtained by steam reforming city gas, LPG, naphtha, or the like is used. Used. Methanol can also be used as a reforming raw material.

In the present invention, the time required for each step of the pressure fluctuation adsorption / separation operation varies depending on the amount of the source gas introduced into the PSA apparatus, the concentration of the target component in the source gas, the adsorption amount of the target component in the adsorption tower, and the like. However, for example, the adsorption step
300-360 seconds, the depressurization step is 120-180 seconds, the blowdown step is 120-180 seconds, the purge step is
120 to 180 seconds, and the pressurization step is 120 to 180 seconds. Further, the pressure and the like during the adsorption step in the adsorption tower fluctuate depending on each process time, the amount of raw material gas introduced, and the like. For example, the pressure during the adsorption step is 0.7 to 0.8 MPa, and the pressure during the depressurization step is , 0.4 to 0.7 MPa, the pressure during the blowdown step is 0.05 to 0.4 MPa, the pressure during the purge step is 0.0 to 0.05 MPa, and the pressure during the pressure increase step is:
0.2 to 0.7 MPa.

[0023]

Next, specific embodiments of the present invention will be described. FIG.
FIG. 4 is an explanatory diagram of a PSA device applied to an embodiment of the present invention, and FIG. 4 is a diagram showing a flow of a load amount calculation method for obtaining a preceding device load amount. In FIG. 3, this PSA
The device was filled with zeolite as adsorbent, capacity 8
00 liters of adsorption towers A, B and C, a hydrogen holder 2 for storing hydrogen which is a product gas separated and recovered in the adsorption tower, an off-gas holder 3 for storing off-gas discharged from the adsorption tower, It mainly comprises pipes 4 for connecting the adsorption towers A, B, and C, the hydrogen holder 2 and the off-gas holder 3, and valves (not shown) provided on the pipes 4. The rated load is, for example, 1
00Nm ³ / hr. Reference numeral 1 denotes a source of the source gas 5. Further, the hydrogen holder 2 is connected to a gas destination device not shown.

Using the apparatus shown in FIG. 3, city gas is reformed from a raw material gas supply source 1, hydrogen: 76 vol%, CO: 2 v
ol%, CO ₂ : 19 vol%, CH ₄ : 3 vol% A hydrogen-rich raw material gas 5 is introduced into adsorption towers A, B and C of a PSA apparatus, and the adsorption towers A, B and C perform three steps of adsorption process. And a series of pressure-fluctuation adsorption / separation operations in which one cycle includes nine steps consisting of a pressure reduction step, a pressure equalization step, a blowdown step, a purge step, a pressure equalization step, and a pressure increase step (see FIGS. 1 and 2). Are sequentially performed in the adsorption towers of A, B, and C by shifting three steps, and the inter-process pressure in the product gas holder 2 is measured in accordance with the load calculation calculation flow shown in FIG. 4 (A in FIG. 4). Average value of change in holder pressure during pressure reduction step of adsorption tower B (P _1a )
Adsorption and variation average value of voltage step-up process of the adsorption tower C average of (P _1b) and (P _n-2), pressure reduction step variation average value of the holder pressure during the adsorption tower A and (P _2a) The average change amount is calculated by the following equation (1) based on the average value (P _n-1 ) with the average change amount (P _2b ) during the pressure raising step of the tower B (B in FIG. 4). The product gas holder pressure (P _n ) after the value correction is obtained, and P _n (MPa) = [(P _n−2 ) + (P _n−1 )] / 2 (1) Correction of the calculated variation average value The apparatus load is calculated by the following equation (2) based on the product gas holder pressure (P _n ) after that (D in FIG. 4), and the apparatus load (Y _n ) of the PSA apparatus corresponding to the holder pressure after the change amount average value is corrected. I asked.

Y _n (%) = A · P _n + B (2) (P _n : MPa) FIG. 5 corresponds to the pressure value (MPa) in the gas holder in the apparatus shown in FIG. FIG. 4 illustrates a first-order approximation formula for obtaining the device load. In the drawing, the gain A of the first-order approximation formula in the device of FIG. 3 is −500, and the bias B is 350. Therefore, the above equation (2) is as follows: Y _n (%) = − 500 · P _n +350 (2) ′.

Next, the difference (P _n−2 −) between (P _{n− 2} ) and (P _n−1 ), which are the average values of the change amount average values, is obtained.
Based on (P _n-1 ) and the weight coefficient (K) at the time of calculating the apparatus load, the preceding fluctuation amount (Z _n ) of the apparatus load is predicted by the gas use fluctuation amount prediction (C in FIG. 4) by the following equation (3). , Z _n = (P _n−2 −P _n−1 ) · K (3) (K = weight coefficient) The determined device load advance fluctuation amount (Z _n ) and the holder after the change amount average value correction. Based on the device load amount (Y _n ) corresponding to the pressure, addition (E in FIG. 4) is performed by the following equation (4), and PSA
Prior device obtains load (X _n) of the _{device, X n = Y n + Z} n ··· (4) below, obtains the preceding device load continuously by repeating the same operation, obtained prior device load (X _n )), Hydrogen was produced by controlling the amount of raw material gas introduced into the pressure fluctuation adsorption separation apparatus and the time required for each processing step in each adsorption tower by calculating the load amount of each apparatus (F in FIG. 4). , The hydrogen usage of the device used 5 connected to the downstream of the hydrogen holder 2
Purity of 99.9 in an amount following 0 to 100 Nm ³ / hr.
99 vol% of hydrogen was produced and could be supplied reliably.

At this time, as the weighting factor (K), K = K which is corrected based on the capacity of the hydrogen holder 2, feedforward gain, and the like, and is obtained based on the tuning result for calculating the optimum value according to the operating condition of the apparatus of FIG. 1.3 was used. At this time, the amount of the raw material gas 5 introduced into the adsorption tower is
It fluctuates at 90 to 180 Nm ³ / hr, the time of the adsorption step is 300 to 600 seconds, and the time of the pressure reduction step is 150 to 300
Seconds, the time for the pressure equalization step is 20 to 30 seconds, the time for the blowdown step is 150 to 300 seconds, and the time for the purge step is 150.
３００300 seconds, the time of the pressure equalizing step varied from 20 to 30 seconds, and the time of the pressure increasing step varied from 150 to 300 seconds. Also,
The pressure in the adsorption tower during the adsorption step is 0.7 to 0.8 MPa, the pressure in the tower during the pressure reduction step is 0.4 to 0.7 MPa, and the pressure in the pressure equalization step is 0.2 to 0.4 MPa. The pressure in the tower in the down step is 0.0 to 0.2 MPa, the pressure in the tower in the purge step is 0.0 to 0.05 MPa, the pressure in the tower in the pressure equalization step is 0.2 to 0.4 MPa, The internal pressure fluctuates at 0.2 to 0.7 MPa, respectively, the pressure of the hydrogen holder 2 fluctuates at 0.4 to 0.7 MPa,
The pressure (P _n ) in the hydrogen holder after the correction of the average value of the change amount is 0.1.
At 5 to 0.6 MPa, the apparatus load corresponding to the holder pressure after the change amount average value correction fluctuates at 65 to 85%, respectively.
The difference (P _n−2 −P _n−1 ) between the two values (P _n−2 ) and (P _n−1 ) obtained by averaging the average value of the change amount of the pressure in the hydrogen holder, and the weight coefficient ( prior variation of the device load determined by the product of the K) (Z _n) varies from 5 to 10, the preceding load of PSA device varied from 70 to 80.

According to the present embodiment, the apparatus obtained by correcting the average value of the pressure change amount of the hydrogen holder 2, the difference between two values obtained by averaging the average value of the change amount, and the weight coefficient (K) for calculating the apparatus load. Predicting the pre-load of the PSA device based on the pre-load variation, and controlling the amount of the raw material gas 5 introduced into the PSA device and the time required for each of the steps in each adsorption tower of the PSA device based on the pre-load. As a result, the control disturbance by the PSA apparatus was eliminated, the apparatus load following speed was improved, and hydrogen following the amount of hydrogen used by the hydrogen using apparatus could be produced stably and supplied reliably.

[0029]

According to the invention described in claim 1 of the present application,
The control disturbance in the PSA device can be eliminated, and the load following speed can be improved. Further, since a huge product gas holder is not required, the size of the apparatus can be reduced and the equipment cost can be reduced. According to the invention described in claim 2 of the present application, by having the pressure equalizing step, in addition to the effects of the above invention, the separability of each component gas is improved, and the recovery rate of the target component is further improved.

According to the third aspect of the present invention, in addition to the effects of the above-described invention, hydrogen can be stably produced and reliably supplied in accordance with the amount of use of the hydrogen destination apparatus.
According to the invention described in claim 4 of the present application, control disturbance in the PSA device can be eliminated, and the load following speed can be improved. Further, since a huge product gas holder is not required, the size of the apparatus can be reduced and the equipment cost can be reduced. According to the invention as set forth in claim 5 of the present application, in addition to the effects of the above-described invention, hydrogen can be stably produced and reliably supplied in accordance with the usage amount of the hydrogen usage destination device.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing the principle of the present invention.

FIG. 2 is an explanatory diagram showing the principle of the present invention.

FIG. 3 is an explanatory diagram of a PSA device applied to one embodiment of the present invention.

FIG. 4 is an explanatory diagram of an apparatus load calculation method according to an embodiment of the present invention.

FIG. 5 is a diagram showing the relationship between the pressure inside the gas holder and the device load corresponding to the pressure in the embodiment of the present invention.

FIG. 6 is an explanatory diagram of a PSA device.

FIG. 7 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Source gas supply source, 2 ... Hydrogen holder, 3 ... Off gas holder, 4 ... Piping, 5 ... Source gas, A, B, C ... Adsorption tower, 61 ... Reforming raw material, 62 ... Raw material reforming apparatus, 63 ... reformed gas, 64 ... PSA device, 65 ... product gas holder, 66
... product gas, 67 ... water vapor, 68 ... fuel, 69 ... combustion air, 70 ... off gas.

Continued on the front page (72) Inventor Tomoki Sugaya 5-2-10 Higashi Terao, Tsurumi-ku, Yokohama-shi, Kanagawa F-term (reference) 4D012 CA20 CB16 CD07 CE01 CE02 CF01 CF03 CJ01 CJ02 CJ07 4G040 EA02 EA03 EA06 EB16 EB43 EC02 FA04 FB04 FC03 FD01 FD02 FE01 4H060 AA01 BB08 BB22 BB33 CC12 DD01 DD02 DD03 EE03 FF03 FF13

Claims (5)

[Claims] 1. A raw material gas is introduced into a pressure fluctuation adsorption separation (PSA) device having at least three adsorption columns filled with an adsorbent, and each of the adsorption columns adsorbs easily adsorbable components in the raw material gas. An adsorbing step of separating and recovering the hardly adsorbable components by adsorbing the adsorbent on the adsorbent; a depressurizing step of using the off-gas flowing out of the adsorbing tower by depressurizing the adsorbing tower after the adsorbing step as a purge gas of another adsorbing tower; A blowdown step of collecting the off-gas released from the adsorbent by further reducing the pressure of the adsorption tower after the step is completed, and flowing out of the adsorption tower during the pressure reduction step of another adsorption tower to the adsorption tower after the blowdown step is completed. A purging step of introducing off-gas and purging the inside of the tower,
A series of pressure-fluctuation adsorption / separation operations including a step of introducing a product gas into the adsorption tower after the purging step and a step of increasing the pressure to sequentially increase the pressure-concentration adsorption separation operation at predetermined intervals to collect specific components in the raw material gas, An industrial gas production method using a pressure fluctuation adsorption / separation device, which is sent to a device at a gas use destination via a device, wherein a pressure fluctuation in the product gas holder is measured, and a change amount average value of the product gas holder is measured based on the measured value. The corrected pressure (P _n ) is obtained, the device load of the pressure fluctuation adsorption / separation device is obtained based on the pressure after the change amount average value correction, and the measured value of the pressure fluctuation of the product gas holder and the device load calculation time are calculated. Of the apparatus load of the pressure fluctuation adsorption / separation apparatus is calculated based on the weight coefficient of the pressure fluctuation adsorption separation apparatus, and the apparatus load preceding fluctuation amount is calculated as the pressure (P _n ) after the correction of the average value of the change amount. In addition to the apparatus load determined based on the preceding apparatus load, the preceding apparatus load is used, and based on the preceding apparatus load, the introduction amount of the raw material gas to the pressure fluctuation adsorption separation apparatus and the time required for each of the steps are controlled. Industrial gas production method using a pressure fluctuation adsorption separation device. 2. A pressure equalizing step between the pressure reducing step and the blow-down step, in which the pressure in the pressure reducing step is communicated with the other adsorption tower in which the purging step has been completed to equalize the pressure in the tower. Having a pressure equalizing step between the purging step and the pressure increasing step to equalize the column pressure by communicating the adsorption tower after the purging step and the other adsorption tower after the depressurizing step. An industrial gas production method using the pressure fluctuation adsorption separation device according to claim 1. 3. The industrial gas production according to claim 1, wherein the source gas is a hydrogen-containing gas, and a component recovered from the source gas is hydrogen. Method. 4. A pressure swing adsorption separation (PS) having at least first, second and third adsorption columns packed with an adsorbent.
A) A raw material gas is introduced into an apparatus, and in each of the adsorption towers, an easily adsorbable component in the raw material gas is adsorbed by an adsorbent to separate and recover hardly adsorbable components, and an adsorption step in which the adsorption step is completed. A decompression step in which the offgas flowing out of the adsorption tower by depressurizing the tower is used as a purge gas for another adsorption tower, and the adsorption tower after the decompression step is communicated with the other adsorption tower after the purge step to communicate with each other. A pressure equalizing step for equalizing the pressure, a blow-down step of further reducing the pressure of the adsorption tower after the pressure equalizing step is completed, and collecting the off-gas released from the adsorbent; A purging step of introducing an off-gas flowing out of the adsorption tower during the depressurization step of the adsorption tower to purge the inside of the tower, and connecting the adsorption tower after the purging step and the other adsorption tower after the depressurization step to one another. Equalize tower pressure A series of pressure fluctuation adsorption / separation operations having a pressure equalizing step and a pressure increasing step of introducing and increasing the pressure of the product gas into the adsorption tower after the pressure equalizing step has been completed are sequentially repeated at predetermined intervals, and specific components in the raw material gas are repeated. Recovering and sending it to a device where gas is used through a product gas holder, using a pressure fluctuation adsorption / separation device, wherein the pressure of the product gas holder is measured, and the second adsorption tower in the product gas holder is measured. Pressure during the pressure reduction step ( _P1a )
(P _n-2 ) of the average pressure (P _1b ) during the pressure increase step of the third adsorption tower, the average pressure (P _2a ) during the pressure reduction step of the first adsorption tower, and the pressure increase of the second adsorption tower. Average pressure during process ( _P2b )
Then, the product gas holder pressure (P _n ) after the correction of the average value of the variation is obtained from the following equation (1) based on the average value (P _n-1 ) of the following formula: P _n (MPa) = [(P _n−2 ) + (P _n-1 )] / 2 (1) Based on the product gas holder pressure (P _n ) after the correction of the average value of the variation, the load (Y) of the pressure fluctuation adsorption / separation apparatus is calculated by the following equation (2). _n ), Y _n (%) = A · P _n + B (2) (where A and B are coefficients of a first-order approximation formula for obtaining an apparatus load from a product gas holder pressure value, A is
The gain, B, is the bias. Then, the average value (P _n−2 ) of the average pressure of the product gas holder and (P _n−2 )
_n-1 ) based on the difference ( _{Pn-2- Pn-1} ) and the weighting coefficient (K) at the time of calculating the device load, the following equation (3) is used to calculate the preceding fluctuation amount of the device load of the pressure fluctuation adsorption / separation device. (Z _n ) is predicted, and Z _n = (P _n−2 −P _n−1 ) · K (3) (K = weight coefficient) The predicted device load preceding fluctuation amount (Z _n ) by the following equation (4), a device load the product obtained on the basis of the gas holder after the variation average value correction (Y _n) in addition to the preceding device load _{(X n), X n =} Y n + Z n ·· (4) Hereinafter, the same operation is sequentially repeated to obtain the preceding apparatus load, and based on the obtained preceding apparatus load (X _n ), the amount of the raw material gas introduced into the pressure fluctuation adsorption / separation apparatus and the above-mentioned respective values in each adsorption tower. An industrial gas production method using a pressure-fluctuation adsorption / separation apparatus, characterized by controlling the time required for a treatment step. 5. The method according to claim 4, wherein the raw material gas is a hydrogen-containing gas, and a component recovered from the raw material gas is hydrogen. .