JPH0780231A - Operation method of pressure swing adsorption equipment - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a method for operating a pressure swing adsorption facility capable of continuously adjusting the product supply amount according to the operating conditions. [Composition] Controlling the rotation speed of the raw material blower, product compressor, and vacuum pump of the pressure swing adsorption equipment, and continuously changing the power consumption of the raw material blower, product compressor, and vacuum pump according to the operating conditions. Let As a result, it is possible to deal with the operating conditions with one facility.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for operating a pressure swing adsorption facility for concentrating and recovering a specific component in a mixed gas by changing the pressure of an adsorbent such as recovery of oxygen or nitrogen in air.

[0002]

2. Description of the Related Art The pressure swing adsorption method (Press)
The recovery itself of the specific gas component by ure Swing Adsorption) is widely known as described in JP-B-63-58614 and JP-A-3-229611.

Taking, for example, the separation and recovery of oxygen from the air, an air is introduced into the adsorption tower by using a pressure swing adsorption apparatus in which a plurality of adsorption towers filled with zeolite as a nitrogen absorbent are arranged. Adsorption step of adsorbing nitrogen to the adsorbent, depressurizing step of depressurizing and adsorbing the adsorbed nitrogen with a vacuum pump, etc., and pressurizing step for introducing adsorbent gas to restore adsorbent adsorption capacity after depressurization The adsorption cycle is alternately combined for each adsorption tower to perform continuous operation.

By the way, the recovery amount of the specific gas component in the pressure swing adsorption equipment needs to be changed from time to time in accordance with other operating conditions. Conventionally, the adjustment of the recovery amount is performed by adjusting the excess recovery gas amount. The amount to be discharged is changed by discharging or off-gassing, or by providing a bypass valve on the product compressor and taking out only the required amount as recovered gas. Therefore, the raw material blower, vacuum pump, and product compressor have 100% load. As a result, the electric power consumption of the entire facility does not change, and the electric power consumption per oxygen generation amount (power source unit) deteriorates.

As a countermeasure against this, for example, as shown in FIG. 5, raw material blowers 2A and 2B for feeding raw material gas to each of the three adsorption towers 1A, 1B and 1C, and high concentration after nitrogen adsorption in the adsorption step Product compressors 3A, 3B for removing oxygen as a product, and adsorption towers 1A, 1B, 1C
Equipment having two vacuum pumps 4A and 4B for sucking the nitrogen adsorbed on the column and discharging it as off-gas has been developed. Reference numeral 17 in the figure is a boost gas flow rate adjusting valve.

In this equipment, two raw material blowers 2A and 2B and product compressors 3A and 3 are used according to the operating conditions.
100% by operating B and vacuum pumps 4A and 4B separately and operating both units at full operation
The operation of. Also, only one of the raw material blower 2A, the product compressor 3A, and the vacuum pump 4A is operated according to the conditions.

With such an operation method, the power consumption can be reduced to 50% at the time of 50% operation, and efficient operation without waste according to the payout amount becomes possible.

[0008]

However, in the pressure swing adsorption equipment shown in FIG. 5, in addition to the conventional equipment, the raw material blower 2B, the product compressor 3B, the vacuum pump 4B, and the valves related thereto are further added. In addition to the above, the problem of securing the installation location of the equipment and the problem of maintenance occur. In the equipment shown in the figure, 100% and 5
Two types of 0% operation are possible, but stepless operation is impossible, and it cannot be said that efficient operation has been sufficiently achieved.

An object of the present invention is to provide a method for operating a pressure swing adsorption facility which can adjust the product supply amount steplessly according to operating conditions without increasing the number of installed raw material blowers, product compressors, and vacuum pumps. To provide.

[0010]

A method of operating a pressure swing adsorption facility according to the present invention comprises a plurality of adsorption towers filled with an adsorbent for adsorbing a specific component gas, and a raw material blower for supplying the raw material gas to the adsorption tower. A raw material gas supply system equipped with a product gas system equipped with a product compressor for taking out the gas after adsorbing the specific gas by the adsorption tower, and an off gas for sucking the specific gas adsorbed in the adsorption tower. In a pressure swing adsorption facility having an off-gas system equipped with a vacuum pump for discharging as, the raw material blower, the product compressor, and the rotation speed of the vacuum pump are controlled, and the raw material blower and the product compression are controlled according to operating conditions. It is characterized in that the power consumption of the machine and the vacuum pump is changed steplessly.

[0011]

Operation: By continuously changing the power consumption of the raw material blower, product compressor, and vacuum pump,
It is possible to respond to the operating conditions with the equipment of the stand, and the power consumption can be changed accordingly.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an outline of a conventional pressure swing adsorption tower equipment equipped with three adsorption towers in order to apply the present invention to separation and recovery of oxygen from air. In addition, in this equipment,
Those corresponding to the conventional example shown in FIG. 5 are denoted by the same reference numerals.

In the figure, each of the adsorption towers 1A, 1B and 1C filled with zeolite has a raw material gas feed system 5 equipped with a raw material blower 6 for feeding the raw material gas to the adsorption towers 1A, 1B and 1C. And the adsorption towers 1A, 1B, 1C
A product gas system 7 equipped with a product compressor 8 for taking out high-concentration O ₂ gas after adsorbing ₂ gas, and an adsorption tower 1A,
Off-gas system 9 equipped with a vacuum pump 10 for sucking the N ₂ gas adsorbed by 1B and 1C and discharging it as off-gas
And a boosting gas system 11 for supplying a part of O ₂ to the adsorption towers 1A, 1B, 1C to boost the pressure. Further, the heating gas system 11 has a heating gas flow rate for controlling the flow rate. A regulating valve 17 is provided. Further, each raw material gas feeding system 5, product gas system 7, off-gas system 9 and boosting gas system 1
On-off valves 13, 14, 15, and 16 are provided at 1, respectively.

FIG. 2 is a combination diagram of operation cycles of the adsorption device shown in FIG. 1. Referring to FIGS. 1 and 2, for example, in the adsorption tower 1A, the valve 13 of the feed gas supply pipe is opened to open the feed gas. Adsorbing step (a) in which the adsorbent adsorbs a specific gas into the adsorption tower 1A, the valve 13 of the raw material gas supply pipeline is closed, the suction gas pipeline valve 15 is opened, and the vacuum pump 10 is used. From the depressurizing step (b) for directly connecting the adsorption tower 1c to absorb the adsorbed gas, and the pressure increasing step (c) for opening the valve 16 and introducing a part of the recovered oxygen into the adsorption tower 1B to pressurize the inside of the tower. Become.

While the adsorption tower 1A is in the adsorption step (a), the adsorption towers 1B and 1C are in the pressurization step (c) and the depressurization step (b), and while the adsorption tower 1A is in the depressurization step (b). The adsorption towers 1B and 1C are in the adsorption step (a) and the pressurization step (c), and while the adsorption tower 1A is in the pressurization step (a), the adsorption towers 1B and 1C are in the depressurization step (b) and the adsorption step (a). ), Each cycle is set so that continuous operation of the entire system is possible.

In this pressure swing adsorption facility, the raw material blower 6, the product compressor 8 and the vacuum pump 10 are programmed in advance according to the operating conditions, specifically, the oxygen demand of the product oxygen demanding side. The rotation speed is controlled by the inverter according to the plurality of patterns thus formed.

FIG. 3 shows an example of this control. For example,
It has six types of operation modes 1 to 6. The operation mode 1 shows the case where the oxygen generation amount is 100%. In this mode, one step time (eg adsorption, decompression,
Each step of pressurization) is 60 seconds, and the inverter setting values for the raw material blower, vacuum pump, and product compressor are 6% corresponding to 100%.
It is 0 Hz. Similarly, the set value of the boost gas flow rate adjusting valve is also 100% in this mode.

In operation mode 2, the required oxygen generation amount is 90
%, And since the amount of adsorbent in the adsorption tower is constant, the amount of deterioration of the capacity of the raw material blower or the like becomes long during one step,
67 seconds, which is an increase of about 11% in one process time, and the inverter setting value of the raw material blower, vacuum pump, and product compressor is 90% of 54 seconds.
It becomes Hz. Further, the set value of the boost gas flow rate adjusting valve is 90% of that in the operation mode 1. Furthermore, when the oxygen generation amount is changed to 80, 70, 60, 50%,
Each value is set as shown in FIG.

As a result, the raw material blower, the vacuum pump,
The load on the product compressor can be reduced as the required oxygen generation amount is reduced, and the oxygen gas of the product can be stably generated.

FIG. 4 is a graph showing the relationship between the amount of O ₂ generated and the power consumption. The solid line is the conventional product 1 equipped with one raw material blower, one product compressor and one vacuum pump, and the broken line is the conventional technology. The conventional product 2 provided with two raw material blowers, two product compressors, and two vacuum pumps, and the one-dot chain line shown in FIG.

As shown in the figure, the conventional product 1 consumes a large amount of power even when the oxygen generation amount is small, and the conventional product 2 has an O ₂ generation amount of about 40% or less. The power consumption is higher than that of this embodiment. On the other hand, in the present embodiment, particularly in the region where the O ₂ generation amount is about 40% or more, the power consumption continuously changes corresponding to the O ₂ generation amount, and efficient operation was confirmed. .

In the above-mentioned embodiment, the column having three adsorption columns has been described, but the present invention is not limited to this, and it can be widely applied to the two column type or the multi column type. is there. Further, in addition to the inverter, the method can be applied to a method of controlling the power consumption by changing the rotation speed by changing the diameter of the driving pulley.

[0023]

As described above, according to the present invention, it is possible to cope with the required product gas amount with a single equipment, and the power consumption can be changed accordingly, so that the efficient operation becomes possible.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a pressure swing adsorption tower facility equipped with three adsorption towers.

FIG. 2 is a diagram showing an operation process of each adsorption tower in the apparatus shown in FIG.

FIG. 3 is a diagram showing an example of control of the device shown in FIG.

FIG. 4 is a diagram showing a relationship between an oxygen generation amount and power consumption.

FIG. 5 is a diagram showing an outline of a conventional pressure swing adsorption facility.

[Explanation of symbols]

 1A, 1B, 1C Adsorption tower 5 Raw material gas feeding system 6 Raw material blower 7 Product gas system 8 Product compressor 9 Off gas system 10 Vacuum pump 11 Boosting gas system 13-16 Open / close valve 17 Boosting gas flow rate adjusting valve

Claims (1)

[Claims] 1. A plurality of adsorption towers filled with an adsorbent for adsorbing a specific component gas, a raw material gas supply system including a raw material blower for supplying the raw material gas to the adsorption tower, and a specific gas by the adsorption tower. Pressure having a product gas system equipped with a product compressor for taking out the gas after the adsorption tower, and an off gas system equipped with a vacuum pump for sucking the specific gas adsorbed in the adsorption tower and discharging it as an off gas In the swing adsorption facility, the rotation speeds of the raw material blower, the product compressor, and the vacuum pump are controlled, and the power consumption of the raw material blower, the product compressor, and the vacuum pump is changed steplessly according to operating conditions. A method of operating a pressure swing adsorption facility, which is characterized in that