JPH0549839A - Adsorption separating device - Google Patents

Abstract

PURPOSE:To provide an adsorption separating device having high practical utility such as being capable of enough exhibiting catalytic ability or saving the amount of a catalyst. CONSTITUTION:In a reaction column housing a catalyst provided together with a separating column 11 housing an adsorbent 12 and a heating mean 13 for heating the adsorbent 12, separation is carried out by adsorbing an effective component in a gaseous 1 with the absorbent 12. The effective component and a harmful component separated from the effective component are allowed to desorb from the adsorbent 12 by heating the adsorbent 12 with the heating mean 13, and then the harmful component being mixed with the effective component is removed selectively upon catalytic reaction by feeding the desorbed gas from the separating column 11 to the reaction column, except for the initial stage in the desorbing process of both the components and/or the latter period in which the harmful component is contained in a large amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adsorption / separation device of the type which separates active ingredients in a sample gas by adsorption with an adsorbent.

[0002]

2. Description of the Related Art Conventionally, as an adsorption separation device, in an adsorption process (adsorption step), carbon dioxide gas (effective component) in a combustion gas (sample gas) is separated by adsorption by an adsorbent in a separation tower,
In the desorption process (desorption process), the carbon dioxide adsorption / separation device that heats the adsorbent to effectively desorb the adsorbed carbon dioxide and can take out the carbon dioxide contained in the combustion gas in a concentrated form. is there.

However, the combustion gas contains components (harmful components) such as carbon monoxide and nitrogen oxides which are harmful to the human body, and these are also adsorbed and separated by the adsorbent together with carbon dioxide in the adsorption process. In the desorption process, harmful components are separated from the adsorbent and coexist with carbon dioxide. In this way, carbon dioxide containing harmful components is difficult to use for civilian use, so a carbon dioxide adsorption / separation device is equipped with a reaction tower containing a catalyst in the latter stage of the separation tower, and the desorbed gas from the separation tower is installed here. Is introduced to eliminate harmful components as much as possible.

[0004]

However, in the conventional carbon dioxide adsorption separation apparatus, the ability of the catalyst cannot be fully exerted, the harmful components cannot be removed sufficiently, and a large amount of the catalyst is required. However, there was a drawback that it was not practical enough. In view of the above circumstances, it is an object of the present invention to provide a highly practical adsorption / separation device that can fully exhibit the performance of a catalyst or that requires a small amount of catalyst.

[0005]

In order to solve the above-mentioned problems, an adsorption separation apparatus of the present invention comprises a separation column containing an adsorbent and a heating means for heating the adsorbent, and also contains a catalyst. And a reaction tower, the active ingredient in the sample gas is separated by adsorbing the active ingredient in the sample gas, and the adsorbent is heated by the heating means to adsorb and separate the active ingredient together with the active ingredient. Desorbing the harmful components from the adsorbent, and feeding the desorbed gas from the separation column into the reaction column except in the initial stage of the both component desorption process and / or the latter stage when a large amount of harmful components are contained. Therefore, the harmful components mixed in the active ingredient are selectively removed by a catalytic reaction.

Examples of the sample gas and the effective component include, but are not limited to, combustion gas as the sample gas and carbon dioxide gas as the effective component. In the adsorption separation device of the present invention, the initial desorbed gas that appears at the beginning of the desorption process is directly discharged to the outside of the tower without passing through the reaction tower,
Alternatively, the high-temperature desorbed gas in the latter stage, which contains a large amount of harmful components after reaching the high temperature region at the end of the desorption process, may be discharged directly to the outside of the tower (outside the separation tower) without passing through the reaction tower. It is equipped with a means for discharging gas. Both the early desorbed gas and the late desorbed hot gas do not pass through the reaction tower,
In the most preferable mode, only the desorbed gas in the middle is introduced into the reaction column.

[0007]

The operation of the adsorption / separation device of the present invention will be described by taking the case of the carbon dioxide gas adsorption / separation device as an example. In the adsorption process, the combustion gas is sent to a separation tower, and the carbon dioxide gas in the combustion gas is selectively adsorbed by an adsorbent (for example, zeolite) and separated. Then, in the next desorption (regeneration) process, the carbon dioxide gas is desorbed from the adsorbent by heating the adsorbent and is taken out in a concentrated form, and at the same time, the adsorbent is regenerated to return to a state where the adsorption process is possible again. . In the case of the carbon dioxide adsorption / separation device of the present invention, the desorbed gas is sent to a reaction tower containing a catalyst to remove carbon monoxide and nitrogen oxides by a catalytic reaction (not only when harmful components are removed but also harmless). It is possible to obtain carbon dioxide gas in a state in which there is no problem in use (including the case where it is made into a material).

In the carbon dioxide adsorption / separation apparatus of the present invention, the ability of the catalyst can be fully exhibited. In the desorption process, the feeding of the combustion gas into the separation tower is stopped and the heating of the adsorbent is started, but the initial desorption gas contains much oxygen in the combustion gas remaining in the separation tower. However, conventionally, this oxygen interferes with the reaction progress of the catalyst (for example, a three-way catalyst supporting platinum) in the reaction column at the latter stage, and therefore the catalyst cannot be fully exerted its capacity. However, in the apparatus of the present invention, since the initial desorbed gas generated at the beginning of the desorption process is not introduced into the reaction tower, the inhibition of the reaction progress of the catalyst due to oxygen is eliminated, and as a result, the catalyst is sufficiently depleted. You can exercise your ability.

In this case, the initial stage (for example, about 1 to 2 minutes)
The desorbed gas generated during will be thrown away,
The total amount of carbon dioxide taken out is almost unchanged. This is because the temperature is low at the early stage and the amount of desorbed carbon dioxide gas is small, and the amount of carbon dioxide gas in the discarded initial desorbed gas is a small amount from the total amount. The carbon dioxide adsorption / separation device of the present invention requires a small amount of catalyst. At the end of the desorption process, the temperature rises and a large amount of harmful components are desorbed from the adsorbent, but a large amount of catalyst is required to remove all of them. However, in the case of the apparatus of the present invention, since the high temperature desorbed gas in the latter stage containing a large amount of harmful components is not introduced into the reaction tower, the amount of harmful components removed by using the catalyst is reduced accordingly. The smaller the amount of harmful components, the smaller the amount of catalyst.

Then, the high-temperature desorbed gas at the latter stage when the temperature of the separation tower becomes, for example, 250 ° C. or higher is discarded, but also in this case, the total amount of carbon dioxide gas taken out is almost unchanged. The reason is that the carbon dioxide gas has already been desorbed in the latter half of the period when the temperature of the separation tower reaches, for example, 250 ° C. or higher, and the amount of carbon dioxide gas in the discarded high-temperature desorption gas in the latter half is less than the total amount. This is because it is a small amount.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A carbon dioxide gas adsorption / separation apparatus (hereinafter referred to as "separation apparatus" as appropriate) which is an embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a schematic configuration around a separation tower of a separation apparatus according to an embodiment.
Represents a schematic configuration around the reaction tower of this separation device. 1 and 2 are partially duplicated so that the connection between them can be easily understood.

The separation apparatus of the embodiment is provided with a reaction tower 14 in the latter stage of the carbon dioxide adsorption separation tower 11, and the gas desorbed from the separation tower 11 is introduced into the reaction tower 14. As shown in FIG. 1, the carbon dioxide adsorption separation tower 11 contains a zeolite adsorbent 12 which is an adsorbent for carbon dioxide, and a heater (heating means) 13 for heating the adsorbent 12.
Is provided.

Combustion gas 1 into the carbon dioxide adsorption separation tower 11
The introduction system of is as follows. That is, the inlet 23 of the carbon dioxide adsorption separation tower 11 is connected to the water heater 19 via the connecting pipes 20 and 21, and the combustion gas 1 generated in the water heater 19
Is sent by the pump 18. A valve 3 is provided at the inlet 23 so that the shape memory spring 6 can automatically open and close the valve as required.

The connection system of the carbon dioxide adsorption separation tower 11 and the reaction tower 14 is as follows. That is, the outlet 24 of the carbon dioxide adsorption separation tower 11 is connected to the reaction tower 1 through the valve 4 and the connecting pipe 27.
4 and the desorbed gas from the outlet 24 enters the reaction tower 14. However, the desorbed gas in the early stage and the hot desorbed gas in the latter period are directly discharged to the outside of the tower, and only the desorbed gas in the meantime is sent from the outlet 24 to the reaction tower 14. That is, this separation device is equipped with a gas discharge means for discharging the desorbed gas from the carbon dioxide adsorption separation tower 11 to the outside of the tower without passing through the reaction tower 14. The configuration around the gas discharging means will be described below.

In addition to the outlet 24, the carbon dioxide adsorption / separation tower 11 is provided with two outlets 22 and 25 which directly communicate with the outside of the separation tower. The initial desorbed gas is discharged from the outlet 22 to the outside of the tower. The late hot desorbed gas is discharged from the outlet 25 to the outside of the tower, and only the desorbed gas in the meantime is sent from the outlet 24 to the reaction tower 14. The valves 2, 4, 5 open and close the outlets 22, 24, 25 so that the desorbed gas is discharged and introduced in this manner, but the movement of the valves themselves is caused by the shape memory springs 6, 7, 8 ,.
It is automatically controlled by 9.

The shape memory spring 6 fixed to the support 10 at an intermediate position is in an extremely soft state below the transformation temperature, so that the valve 2 fixed at one end has its submerged outlet 22 opened by its own weight, and the other end. The valve 3 fixed to is the combustion gas 1
The pressure is pushed up to open the inlet 23. This shape memory spring 6 recovers its shape and expands above the transformation temperature,
In this case, the valve 2 is pushed up to close the outlet 22 and the valve 3 is pushed down to close the inlet 23.

The shape memory springs 7 to 9 are also in an extremely soft state below the transformation temperature, the valves 4 and 5 are pressed by the pressure of the combustion gas 1, and the outlets 24 and 25 are closed. Above the transformation temperature, the shape memory spring 8 recovers its shape and expands, and the shape memory springs 7 and 9 recover its shape and contract. The shape memory springs 7 and 9 are designed to recover their shapes at a higher temperature than the shape memory springs 6 and 8. Further, in the adsorption process, the internal temperature of the carbon dioxide adsorption / separation column 11 is prevented from rising to the reverse transformation temperature at which the shape memory springs 6, 7, 8, 9 recover their shapes.

On the other hand, a catalyst 15 is housed in the reaction tower 14. Here, a three-way catalyst supporting platinum is used as the catalyst 15. The reaction tower 14 is the heater 1
The temperature is raised to a temperature at which the catalyst reaction is activated by 6 and the catalytic reaction becomes most active. Next, the adsorption process and desorption process in the above-mentioned separation device will be described.

-Adsorption process-In the adsorption process, the combustion gas 1 generated in the water heater 19 is fed into the carbon dioxide adsorption separation tower 11. Since the inside of the carbon dioxide adsorption separation tower 11 is below the reverse transformation temperature of each shape memory spring, all the shape memory springs 6, 7, 8, 9 are in an extremely soft state, the inlet 23 and the outlet 22 are open, and the outlet 2
4, 25 are closed.

The carbon dioxide gas in the combustion gas 1 is adsorbed by the zeolite adsorbent 12 together with the harmful components, and the remaining non-adsorbed gas 31 exits from the outlet 22. After operating in the adsorption process for a predetermined time, the process proceeds to the desorption process. -Desorption process-In the desorption process, the heater 13 is operated (turned on).
Then, the carbon dioxide adsorption separation tower 11 is heated. As the heater 13 is operated, the zeolite adsorbent 12 in the carbon dioxide gas adsorption / separation tower 11 is heated and gradually rises in temperature.

When the temperature reaches the reverse transformation temperature of the shape memory springs 6 and 8, the shape recovers and expands, so that the valve 2 closes the outlet 22 and the valve 3 opens the outlet 24. The outlet 24 is closed when the valve 4 is at both ends of its travel range and is open when it is at its midpoint. The valve 5 is pushed by the pressure of the desorbed gas to close the outlet 25. The outlet 22 is open until the outlet 24 is opened, and the desorbed gas 2
6 is discharged directly from the outlet 22 to the outside of the tower. That is, the initial desorbed gas 26 containing a large amount of oxygen is not sent to the reaction tower 14.

After the outlet 24 is opened, the desorbed gas is sent to the reaction tower 14 to remove harmful components such as carbon monoxide and nitrogen oxides, and as shown in FIG.
It is sent out from the connecting pipe 28 as 0. When the temperature inside the carbon dioxide gas adsorption / separation tower 11 further rises, it reaches a temperature at which a large amount of harmful components are desorbed. The temperature near this temperature is set as the reverse transformation temperature of the shape memory springs 7 and 9,
It deforms and contracts. The valve 4 closes the outlet 24 and the valve 5 opens the outlet 25 as the shape memory springs 7 and 9 are deformed. Therefore, the hot desorbed gas 17 in the latter stage is also discharged directly from the outlet 25 to the outside of the tower and is not sent to the reaction tower 14.

As described above, in the desorption process, both the initial desorption gas containing a large amount of oxygen and the latter desorption gas containing a large amount of harmful components are directly discharged to the outside of the separation column, and are fed to the reaction column 14. Since it is not sent, the catalyst can fully exert its ability, and the concentrated carbon dioxide gas 30 with a small harmful component content can be obtained without requiring a large amount of the catalyst.

[0024]

As described above, in the adsorption separation apparatus of the present invention, the desorbed gas in the early stage of the desorption process or the hot desorbed gas containing a large amount of harmful components in the latter stage is prevented from passing through the reaction tower. Therefore, the ability of the catalyst can be fully exerted, and an active ingredient having a low harmful component content can be obtained without requiring a large amount of the catalyst.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration around a separation tower of a separation device according to an embodiment.

FIG. 2 is an explanatory diagram showing a schematic configuration around a reaction tower of a separation device according to an example.

[Explanation of sign]

 1 Combustion Gas (Sample Gas) 11 Carbon Dioxide Adsorption Separation Tower (Separation Tower) 12 Zeolite Adsorbent (Adsorbent) 13 Heater (Heating Means) 14 Reaction Tower 15 Catalyst 17 High Temperature Desorption Gas 26 Late Desorption Gas 30 concentrated carbon dioxide (active ingredient)

Claims (2)

[Claims] 1. A separation tower containing an adsorbent, a heating means for heating the adsorbent, and a reaction tower containing a catalyst, wherein the adsorbent is an active ingredient in a sample gas. Are separated by adsorbing the adsorbent, and by heating the adsorbent by the heating means, the active ingredient and the harmful ingredient adsorbed and separated together with the active ingredient are desorbed from the adsorbent. Except for the early stage and / or the late stage when a large amount of harmful components are contained, the desorbed gas from the separation column is sent to the reaction column to selectively remove harmful components mixed in the active components by catalytic reaction. Adsorption separation device. 2. The adsorption separation device according to claim 1, wherein the sample gas is a combustion gas, and the effective component is carbon dioxide gas.