JPH04235712A - Method for regenerating adsorbent of adsorption column - Google Patents

Abstract

PURPOSE:To provide a method for regenerating adsorbents wherein the consumption of gas of high purity which is used as regeneration gas for an adsorption column can be reduced as far as possible in the technology to remove impurities in raw gas by adsorption. CONSTITUTION:When at least two or more adsorption columns 1a, 1b are provided and regeneration operation of adsorbents in the columns is performed, two kinds of regeneration gases are used, one being high purity gas and the other being other than said gas, for example, raw gas. And two regeneration gas lines are provided and at first the raw gas is used as regeneration gas and then the high purity gas is used as regeneration gas to regenerate adsorbents. Since gas other than gas of high purity is used partially in a regeneration operation, consumption of high purity gas used in regeneration operation can be minimized, so that high purity gas can be produced with a high degree of yield.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an adsorption separation technology in which a trace amount of impurities in a raw material gas is adsorbed and gradually removed by an adsorption operation, and a gas containing the adsorbed component as the main component is continuously produced.
The present invention relates to an adsorbent regeneration method for regenerating and reactivating an adsorbent saturated with impurity adsorption.

0002

[Prior Art] Conventional devices include, for example, Japanese Unexamined Patent Publication No. 58-17
As described in No. 775, an oxygen-rich gas containing argon derived from a rectification column of an air separation device is used as a raw material gas, the gas is introduced into an adsorption column, and oxygen is adsorbed and gradually removed to produce argon. There is a way to do it. In this method, first, the impurity nitrogen in the raw material gas is adsorbed and gradually removed in a first adsorption tower, and then oxygen is adsorbed and gradually removed in a second adsorption tower, and the adsorbed component argon is collected. be. In addition, as a regeneration gas for regenerating adsorbents that have become saturated with impurities and have lost their activity,
The adsorbents in both adsorption towers use a gas whose main component is the component to be adsorbed. The idea is to use this to activate the adsorbent and continuously produce argon.

0003

[Problems to be Solved by the Invention] The above prior art is an adsorbent regeneration method for reactivating an adsorbent that has become saturated with impurity adsorption and has lost its adsorption activity. is a gas that is an adsorbed component in an adsorption operation, that is, a highly purified gas containing the adsorbed component as a main component, or a product gas, and all regeneration gas for the regeneration operation is performed using this gas. When the regeneration gas flows in contact with the adsorbent, it mixes with impurities released from the adsorbent,
The gas becomes a low-purity gas and is discharged outside the system as waste gas. Therefore, if the amount of regeneration gas is, for example, 20% of the amount of raw material gas, the amount of high-purity gas produced as a product whose main component is the adsorbed component will be 80%. That is, 20% of the highly purified gas that has been made highly purified by adsorption and gradual removal of impurities in the adsorption tower is discharged outside the system as waste gas, which is not a special measure in terms of a highly efficient gas purification method. Therefore, in order to produce high-purity gas with high efficiency in an adsorption system, it is necessary to use a regeneration gas used in the regeneration operation of the adsorbent, that is, a gas whose main component is the adsorbed component, or a high-purity gas. It is essential to reduce the amount.

[0004] The present invention aims at regenerating an adsorbent by minimizing the amount of gas used as a regeneration gas during the regeneration operation of the adsorbent, which is mainly composed of the adsorbed component purified in an adsorption tower, or a high-purity gas. The purpose is to provide a method.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the regeneration gas used during regeneration of the adsorbent must be a gas whose main component is the adsorbed component purified in an adsorption tower, or a high-purity gas. This can be achieved by using a combination of and a gas other than the above gas.

[0006] The present invention provides the following features during the regeneration operation of the adsorbent:
First, when the temperature of the adsorbent is raised or when the temperature of the adsorbent is high, a gas other than the gas containing the adsorbed component as the main component in the adsorption tower, or a high purity gas is used. Any gas other than the above gas is used as a regeneration gas, the impurities adsorbed on the adsorbent are released from the system along with the gas, and then a gas containing the adsorbed component as the main component or a high purity gas is used. The present invention relates to a method for regenerating an adsorbent in an adsorption tower, which is characterized in that the temperature of the adsorbent in the adsorption tower is lowered and the adsorbent is regenerated using the adsorbent as a regeneration gas.

[0007]

[Operation] Generally, if the components to be adsorbed by the adsorbent are the same, the adsorption capacity of the adsorbent increases significantly as the adsorption temperature of the adsorbent becomes lower. For example, trace amounts of lower hydrocarbons can be almost completely adsorbed and removed by cooling a diatom product (adsorbent) with liquid oxygen or the like. on the other hand,
When the adsorbent is operated at high temperature, for example, at an adsorption temperature of about 200° C., the adsorbent has almost no adsorption capacity. Adsorbent regeneration can be done using vacuum, but most of the time it is done by utilizing the temperature characteristics of the adsorbent.

According to the present invention, during the regeneration operation of the adsorbent, if the temperature of the adsorbent is increased or the temperature of the adsorbent is high, the gas other than the gas mainly composed of the adsorbed component in the adsorption tower, or Gases other than high purity gases, i.e.
A gas that may contain adsorbed components to be adsorbed by the adsorption operation is used as a regeneration gas, and in addition, when the temperature of the adsorbent is lowered, or when the temperature of the adsorbent is low, a gas containing the adsorbed components as the main component, or A high-purity gas, that is, a gas containing almost no adsorbed components adsorbed by the adsorption operation, is used as the regeneration gas. As mentioned above, when the temperature of the adsorbent is high, the adsorbent has almost no adsorption capacity. This means that when the temperature of the adsorbent is high, even if the aforementioned gas, that is, the gas containing the adsorbed components to be adsorbed in the adsorption operation, is used as the regeneration gas, the gas containing the adsorbed components as the main component or the high Compared to using pure gas,
There is almost no effect on the regeneration of the adsorbent. Therefore, in the regeneration operation of the adsorbent, by selectively using the above two types of gas as the regeneration gas, the amount of gas mainly composed of the adsorbed component released to the outside, or the amount of high-purity gas used can be minimized. be able to.

[0009]

[Embodiment] An embodiment of the present invention will be explained below with reference to FIG. In the regeneration operation that adsorbs the adsorbed components by the adsorbent and reactivates the adsorbent that has become saturated with the adsorbed components, gas at a temperature higher than the temperature during the adsorption operation, that is, the adsorption temperature, is introduced into the adsorption tower as regeneration gas. a method of raising the temperature of the adsorbent and releasing the adsorbed components out of the system together with the regeneration gas;
There is a method in which regeneration gas is introduced into the adsorption tower at a pressure lower than the adsorption pressure during adsorption operation, and the adsorbed components are released from the system together with the regeneration gas.Here, we will take the former regeneration method as an example. explain.

[0010] Generally, the adsorption tower is composed of at least two or more towers. In FIG. 1, 1a and 1b are adsorption towers. In this embodiment, the adsorption tower 1a performs the adsorption operation, and the adsorption tower 1b performs the regeneration operation. The raw material gas, which is pressurized to at least atmospheric pressure or higher and contains adsorbed components to be adsorbed by the adsorbent, is transported through conduit 1.
00 and the adsorption tower 1 from the conduit 101 through the valve 201.
introduced into a. The adsorption tower is filled with an adsorbent such as synthetic zeolite. Adsorbed components, that is, impurities, in the raw material gas are adsorbed and removed by contact with the adsorbent, and at the outlet of the adsorption tower, a high-purity gas containing the adsorbed component as the main component is obtained. Highly purified gas is supplied with valve 20
2. It is led out of the system as a product gas through the conduit 103.

On the other hand, while the adsorption tower 1a is in adsorption operation, the regeneration operation of the adsorbent in the adsorption tower 1b is performed as follows. By opening the valve 212, the pressure inside the adsorption tower 1b can be lowered from the pressure during adsorption operation. Next, valve 211 and valve 2
By opening 10, a gas other than the gas containing the adsorbed component as the main component, a gas other than the so-called high-purity gas (product gas in this embodiment) is introduced into the adsorption tower 1b. This gas may be, for example, a part of the raw material gas, a gas from the system that generates the raw material gas, or a gas from outside the system. For example, a portion of the raw material gas passes through the conduit 107 and is heated by the heater 300, and then passes through the valve 210 and the valve 21.
1 into the adsorption tower 1b from a conduit 112. Through the above operations, the temperature of the adsorbent in the adsorption tower is adjusted to
The temperature of the regeneration gas is raised sequentially from the inlet to the outlet of the adsorption tower to the temperature set at
14 to the outside of the system. During this time, impurities adsorbed on the adsorbent are desorbed and released to the outside of the system together with the regenerating gas. However, since the gas is not a highly pure gas and contains some impurities, most of the impurities can be desorbed by the adsorbent, but not completely. For this purpose, perform the following operations. First, the valve 210 is closed to stop the supply of raw material gas, and instead the valve 213 is opened to supply a portion of the product gas (high purity gas) to the adsorption tower 1b. That is, a part of the product gas passes through the conduit 115 and is lowered to a low temperature by a cooling means such as a refrigerator 400, and then is introduced into the adsorption tower 1b through the conduit 112 via the valves 213 and 211. In addition to a refrigerator, liquefied gas or the like may be used as the cooling means. The gas replaces the gas in the adsorption tower, and the adsorbent is further cooled to the same temperature as the adsorption operation. The temperature during the adsorption operation is in the range of -200°C to room temperature. The gas passes through the conduit 113 and the valve 212 and is discharged from the conduit 114 to the outside of the system. Furthermore, for cooling the adsorption tower, a cooling means 500 for cooling the adsorption tower itself may be installed instead of a cooling means for only gas. By switching the above operation between the adsorption tower 1a and the adsorption tower 1b, it is possible to continuously produce a high purity gas containing the adsorbed component as the main component. According to this embodiment, the timing of switching the regeneration gas to the adsorption tower, that is, the timing of switching between one part of the raw gas and the other part of the product gas, is determined depending on the component or concentration of impurities to be adsorbed and removed.
By installing a thermometer 600 below the adsorption unit, a more effective switching timing can be determined.

Next, another embodiment of the present invention will be explained with reference to FIG. The difference between this embodiment and the embodiment shown in FIG. 1 is that in this embodiment, the fluid in the adsorption tower is liquid. below,
Description of parts that overlap with the embodiment of FIG. 1 will be omitted. The fluid in this embodiment will be explained using liquefied gas (liquid) as an example. Liquefied gas containing trace amounts of impurities is introduced into the adsorption tower 1a through conduit 100, and after the trace amounts of impurities are adsorbed and removed, it is taken out through conduit 103 as high-purity liquefied gas. It is also possible to gasify it by the heat exchanger 800 and take it out from the conduit 104 in a gaseous state. The fluid necessary for heat exchange is optional and is supplied from the conduit 900 to the heat exchanger 8.
Introduced in 00.

On the other hand, the regeneration of the adsorption tower 1b is carried out as follows. The liquefied gas in the adsorption tower 1b is released to the outside through the conduit 114 by opening the valve 212. At this time, the cold contained in the liquefied gas is recovered by the heat exchanger 801 and released to the outside at approximately room temperature. Any fluid necessary for heat exchange is introduced into the heat exchanger 801 through the conduit 001. Next, a gas whose main component is a component to be adsorbed, that is, a gas other than a so-called high-purity gas, is introduced into the adsorption tower 1b. This gas may be, for example, gas from the system in which this device is installed or gas from outside the system. The gas is passed through conduit 1
08 and 109, and is heated by the heater 300, flows into the adsorption tower 1b through the conduit 112, passes through the valve 212 and the conduit 114, and is discharged to the outside of the system. By this operation, most of the impurities adsorbed on the adsorbent are discharged to the outside of the system together with the regeneration gas. Next, by closing the valve 210 and opening the valve 213, a part of the liquefied gas highly purified in the adsorption tower 1a can flow into the adsorption tower 1b. The liquefied gas replaces the gas in the adsorption tower 1b, and the liquefied gas cools the adsorbent to the temperature at which the adsorption operation is performed. In addition,
A cooling means 500 for cooling the adsorption tower itself may be installed as necessary. Note that the fluid in the conduits 000 and 001 is a gas or liquid from the system in which this device is installed or from outside the system, and is controlled according to the heat exchange conditions.

According to this embodiment, since the fluid during the adsorption operation is liquid, the adsorption tower can be made more compact.

FIG. 3 shows the adsorption characteristics of carbon dioxide (CO2) in type A zeolite. This data is based on a CO2 concentration partial pressure of 300 mmHg calculated from the manufacturer's catalog value. The vertical axis shows the adsorption amount of CO2 per 100 g of adsorbent, and the horizontal axis shows the temperature. The curve shows C at each temperature.
It shows the amount of O2 adsorbed. It can be seen that at temperatures above 250°C, the adsorbent has almost no adsorption capacity. Moreover, the amount of adsorption increases rapidly near 50°C. If we look at the adsorption amounts at 200°C and 25°C, they are 1.5 and 19 (gCO2/100g adsorbent), respectively.

[0016] In this explanation, CO2 was taken as an example, but this tendency is the same for other gases.
At 0℃, the amount of adsorption increases rapidly, and on the contrary, from 250℃ to 300℃
There is almost no adsorption amount at °C. From this, it can be seen that the temperature of the gas containing the adsorbed component as the main component of the regeneration gas of the present invention, or the gas other than the high-purity gas, is from room temperature to 400°C, preferably from 50°C to 300°C.

FIG. 4 shows oxygen (O2) to type A zeolite.
The adsorption isobars of are shown. The horizontal axis shows the temperature, and the vertical axis shows the number of molecules in the cage, that is, the amount of adsorption. This data is described in "Zeolite Basics and Applications", edited by Nobuyoshi Hara. As can be seen from this data, the amount of adsorption increases as the temperature decreases. If the adsorption operation is performed below room temperature, a refrigerant is required. For example, if the refrigerant is liquid nitrogen, the temperature of the adsorbent will be -196°C, and the amount of adsorption at this time will be several tens of times that at 0°C. or,
Under design conditions, for example, when no refrigerant is used due to differences in adsorbed components, that is, when adsorption operation is performed above room temperature, as described in FIG. 3, the amount of adsorption decreases as the temperature rises. From these facts, it can be seen that the adsorption temperature for carrying out the adsorption operation economically and efficiently is -200°C to room temperature.

[0018]

[Effects of the Invention] According to the present invention, during the regeneration operation of the adsorbent, the gas containing the adsorbed component as the main component is introduced into the adsorption tower and released to the outside. Since the amount of gas used or high purity gas other than the high purity gas purified by the adsorption tower can be minimized, the effect of producing high purity gas with high yield can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet diagram of an adsorption device showing one embodiment of the present invention.

FIG. 2 is a flow sheet diagram of an adsorption device showing another embodiment of the present invention.

FIG. 3 is a characteristic diagram showing the CO2 adsorption characteristics of type A zeolite.

FIG. 4 is a characteristic diagram showing O2 adsorption isobars of type A zeolite.

[Explanation of symbols]

1a, 1b...Adsorption tower, 300...Heater, 400,500
...Cooling means, 110, 115...Regeneration gas conduit.

Claims (5)

[Claims] Claim 1: Using an adsorbent such as synthetic zeolite,
In an adsorbent regeneration method for an adsorption tower, which adsorbs and removes trace amounts of impurities contained in the raw material gas and produces gas containing the adsorbed component as the main component, the adsorption capacity is During a regeneration operation to recover the reduced activity of the adsorbent, a gas containing the adsorbed component as the main component or a high-purity gas is combined with any gas other than the above-mentioned gas to regenerate the regeneration gas of the adsorbent. A method for regenerating an adsorbent in an adsorption tower, characterized in that the method is used as an adsorption tower. 2. The temperature of the gas whose main component is the adsorbed component of the regeneration gas of the adsorbent or any gas other than high-purity gas is in the range of room temperature to 400°C, preferably 50°C.
2. The method for regenerating an adsorbent in an adsorption tower according to claim 1, wherein the temperature is in the range of ~300[deg.]C. 3. The temperature during adsorption operation of the adsorption system is -
3. The method for regenerating an adsorbent in an adsorption tower according to claim 1 or 2, wherein the temperature is 200° C. to room temperature, and the pressure inside the adsorption tower during the regeneration operation is lower than the adsorption pressure. 4. During regeneration operation of the adsorption system, the regeneration gas is introduced into the adsorption tower by first introducing a gas other than the gas containing the adsorbed component as a main component or any gas other than high-purity gas. The adsorption tower according to claim 1, claim 2, or claim 3, wherein a gas containing the adsorbed component as the main component or a high-purity gas is then introduced to cool and regenerate the adsorbent. Adsorbent regeneration method. 5. During the adsorption operation of the adsorption system, liquefied gas is introduced into the adsorption tower to remove impurities by adsorption, purify the high-purity liquefied gas or high-purity gas, and during the regeneration operation, the adsorbed components are mainly removed. Component gas or any gas other than high-purity gas is introduced into the adsorption tower, and then gas or liquid containing the component to be adsorbed as the main component, high-purity gas or liquid is introduced, and adsorption is performed. 4. The method for regenerating an adsorbent in an adsorption tower according to claim 2 or 3, wherein the adsorbent is cooled and regenerated.