JPH07163839A - Device for separating and recovering gas - Google Patents

Abstract

PURPOSE:To provide a device for separating and recovering gas whose manufacturing cost and running cost are low and also the recovery efficiency is increased. CONSTITUTION:A device for separating and recovering gas is constituted by providing the device with an adsorption tank 1 for making a prescribed component adsorbed to an adsorbent 24, a purification tank 2 for separating and discharging a component except the specified gas contained in a prescribed component adsorbed in the adsorbent 24 and a regeneration tank 3 which recovers specified gas from the adsorbent 24 and also regenerates the adsorbent 24 to resupply it to adsorption in series through a pipeline 4 and forming a circuit for circulating the adsorbent 24. The adsorption tank 1 and the purification tank 2 may be integrally formed in a line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for separating and recovering, for example, only carbon dioxide gas from exhaust gas discharged along with combustion of heavy oil or coal in a thermal power plant or the like.

[0002]

2. Description of the Related Art Today, an increase in carbon dioxide in the atmosphere is regarded as a cause of global warming, and carbon dioxide in exhaust gas from factories or thermal power plants is regarded as a problem. Among them, a plan for separating and recovering carbon dioxide gas from the exhaust gas generated by the combustion of fossil fuel has been studied, and research and development have been advanced. The existing technology is to install three treatment tanks of the same structure side by side, fill each tank with an equal amount of adsorbent, and switch over a dozen valves to make each tank an adsorption process, a regeneration process, and a purification process. A fixed tank system was adopted in which the steps were performed sequentially.

[0003]

The conventional means is a method of switching the so-called gas flow series, and there is no problem if it is constructed on a small scale, but various problems occur if it is constructed and used on a large scale as it is. Come on. For example, in order to separate and collect a huge amount of carbon dioxide gas generated in a thermal power plant,
An extremely large-scale device is required, and in the conventional device, the valves attached to the gas supply port and the discharge port of each tank must be set to large sizes as the size of the device increases. If the valve is made large, it is technically extremely difficult to ensure airtightness, the purity of the recovered gas is lowered, and the manufacturing cost is increased.Because the valve itself is large, the time required for switching tends to be long, There was a problem that it was difficult to match the processing time with the valve switching time.

The present invention has been made in view of the above circumstances, and even when the device is large in size, it is not necessary to increase the size of the valve accordingly, and the manufacturing cost and running cost can be kept low. Another object of the present invention is to provide a gas separation / recovery device with high recovery efficiency.

[0005]

In an apparatus for selectively adsorbing a predetermined component in a mixed gas with an inorganic adsorbent and separating and collecting only a specific gas, an adsorption tank for adsorbing the predetermined component in the adsorbent, and an adsorption A purification tank for separating and discharging components other than the specific gas among the predetermined components adsorbed by the agent, and a regeneration tank for recovering the specific gas from the adsorbent and regenerating the adsorbent for adsorption again Are arranged in series with the intervening elements to form a circulation path for circulating the adsorbent. The adsorption tank and the refining tank may be integrally provided in a line.

[0006]

The structure in which an adsorbent capable of adsorbing a gas several hundred times the volume is circulated realizes a structure with a very small pipe line and valve as compared with the conventional means for switching the gas flow series.

[0007]

EXAMPLES The structure of the gas separation and recovery apparatus according to the present invention will be described in detail below based on an example of separating and recovering carbon dioxide gas 24 from exhaust gas in a thermal power plant or the like.

In this embodiment, the adsorption tank 1, the refining tank 2, the regeneration tank 3, the storage tank 5, the measuring tank 6, and the depressurization tank 7 are arranged in this order in the order of six processing tanks, and between each processing tank. A raw material gas system 8 constituted by an intervening pipe line 4 for circulating an adsorbent 24 in an annular shape and flowing exhaust gas generated by combustion of fossil fuel as a raw material gas 25, and a carbon dioxide gas system 9 through which high-purity carbon dioxide gas 26 flows. A gas system including a pressure-feeding system 10 through which an offgas 27 for pressure-feeding the adsorbent 24 flows, a pressure equalizing system 11 for balancing the atmospheric pressures of the processing tanks, a cooling unit (not shown), and a heater 12. The temperature adjusting means and the collecting means including the vacuum pump 13 are additionally provided.

The adsorption tank 1 is provided with a feed port for feeding the raw material gas 25 through the pretreatment section 14 in the lower part, and a feed port for discharging the off gas 27 remaining after the carbon dioxide gas 26 is adsorbed, A pipe 4f communicating with the depressurization tank 7 is provided in the upper part, and a dispersion plate 15 for uniformly dispersing the raw material gas 25 in the tank is provided above the inlet of the adsorption tank 1, and further, in the purification tank 2. The pipe 4a communicating with the supply port provided at the upper portion is provided from the dispersion plate 15.

The raw material gas 25 is passed through the pretreatment section 14 to remove the moisture contained in the raw material gas 25,
It is cooled at the same time. The raw material gas 25 flowing into the adsorption tank 1 from the inlet of the raw material gas system 8 flows uniformly in the adsorption tank 1 via the dispersion plate 15 provided in the lower portion of the adsorption tank 1, and passes through the adsorbent 24 from below. The adsorbent 24 and the adsorption tank 1 are cooled. In this way, the raw material gas 25 is fed from the lower side of the adsorption tank 1 and discharged from the upper outlet, so that the adsorbent 24 is always saturated from the lower one. Before all the adsorbents 24 filled in the adsorption layer 1 are saturated, the valve v1 of the conduit 4a is opened for a certain period of time, and a part of the lower part of all the adsorbents 24 existing in the adsorption tank 1 is piped. Road 4
It spontaneously falls into the purification tank 2 via a. Further, the valve v7 is opened for a certain period of time at substantially the same time, and the adsorbent 24 in the unadsorbed state in an amount substantially equal to that of the adsorbent 24 sent out is replenished from the pipe line 4f.

The refining tank 2 is provided with a supply port at the lower part for supplying the high-concentration carbon dioxide gas 26 from the carbon dioxide gas system 9, and the gas discharged from the adsorbent 24 by the supply of the carbon dioxide gas 26 is supplied. A discharge plate for discharging to the supply port of the adsorption tank 1 is provided at the upper part, and a dispersion plate 16 for uniformly dispersing the high-concentration carbon dioxide gas 26 in the tank is provided above the supply port inside the purification tank 2. A pipe line 4b communicating with the supply port provided at the upper part of the regeneration tank 3 is provided from the dispersion plate 16.

The regenerating tank 3 is a part of the carbon dioxide gas system 9, and a gas outlet is provided at the upper part of the carbon dioxide gas system 9 and a gas feed port is provided at the lower part of the carbon dioxide gas system 9. A heat circulation path 18 in which 26 circulates,
Dispersion plate 1 for uniformly dispersing the carbon dioxide gas 26 in the tank
7 is provided above the gas feed port inside the regeneration tank 3, and a pipe line 4c communicating with the supply port provided at the upper part of the storage tank 5 is provided from the dispersion plate 17.

In the heat circulation path 18, the high-concentration carbon dioxide gas 26 extracted from the regeneration tank 3 through the gas outlet is passed through the circulation blower 19 and the heater 12, and the regeneration tank 3 is again supplied through the gas feed port.
The adsorbent 24 filled in the regeneration tank 3 and the regeneration tank 3 are heated by feeding the gas to the regeneration tank 3 through the dispersion plate 17 and causing the heated gas to flow uniformly into the regeneration tank 3. Further, the gas outlet is branched to a gas outlet provided with a vacuum pump 20 so that the carbon dioxide gas 26 having a high concentration is gradually discharged from the gas outlet to lower the atmospheric pressure in the regeneration tank 3. There is. This is because a phenomenon in which the amount of carbon dioxide gas adsorbed per unit volume of the adsorbent 24 in a saturated state is reduced by heating the adsorbent 24 in the regeneration tank 3 or lowering the atmospheric pressure in the regeneration tank 3. Utilizing this, the carbon dioxide gas 26 adsorbed on the adsorbent 24 is to be separated.

When the adsorbent 24 is supplied to the purification tank 2, the circulation blower 19 and the heater 12 start to operate, and the regeneration tank 3
The carbon dioxide gas 26 is separated and released from the adsorbent 24 filled in. The carbon dioxide gas 26 released from the adsorbent 24 is a valve
The adsorbent 24, which has been supplied to the purification tank 2 via v16 and v13 and has been adsorbed from the adsorption tank 1, is saturated. By continuing the supply, nitrogen or the like having lower adsorption priority than carbon dioxide 26 is separated from the adsorbent 24, and carbon dioxide 26 having higher priority is adsorbed. The gas separated from the adsorbent 24 through such a process called concentration or washing is discharged to the inlet of the adsorption tank 1 through the valve v14 and is supplied to the adsorption layer 1 again.

When the concentration step is completed, the valves v13 and v16 are closed and the supply of the carbon dioxide gas 26 to the purification tank 2 is stopped, but the heating of the adsorbent 24 in the regeneration tank 3 is continuously performed,
The carbon dioxide gas 26 released from the adsorbent 24 in the regeneration tank 3 is a valve.
After opening v15, it is pulled by the vacuum pump 13 and collected as product gas in the intermediate tank 20. Adsorbent 24 inside the regeneration tank 3
Is gradually regenerated into a state in which it can be adsorbed, and the regenerated adsorbent 24
Is naturally dropped into the storage tank 5 by opening the valve v3 of the conduit 4c. When the valve v3 is closed, the valve v2 is opened, and the adsorbent 24 that has sufficiently adsorbed only the carbon dioxide gas 26 is transferred from the purification tank 2 to the regeneration tank 3
To fall naturally. The purification tank 2 is also filled with the adsorbent 24 from the adsorption tank 1 as described above, and the steps in the purification tank 2 and the regeneration tank 3 are repeated.

The storage tank 5 into which the regenerated adsorbent 24 falls is a measuring means (not shown) for measuring the amount of the adsorbent 24 discharged.
And a pipe line 4d communicating with a supply port provided in the upper part of the measuring tank 6 is arranged from the lower part of the storage tank 5. Storage tank 5
The adsorbent 24 stored in is cooled during the stay and is weighed every predetermined cycle time. The weighing is performed by measuring the weight, and the valve v4 of the conduit 4d is opened each time, and the adsorbent 24 having a constant weight is discharged to the weighing tank 6.

The measuring tank 6 is connected to the compressed gas discharge port of the pressure feeding system 10 and communicates with the supply port of the depressurizing tank 7 through a pipe line 4.
e is provided. The pumping system 10 fills the pumping tank 22 with a part of the offgas 27 discharged from the adsorption tank 1 via the compressor 21, and the valve v12 is supplied at every predetermined cycle time.
Is opened for a certain period of time to supply compressed gas to the measuring tank 6. When the compressed gas is supplied, all the valves connected to the measuring tank 6 are closed, and the supply of the compressed gas causes the atmospheric pressure in the measuring tank 6 to rise at once. Therefore, by opening the valve v6 of the conduit 4e, the off-gas 27 in the measuring tank 6 is ejected from the measuring tank 6 with high atmospheric pressure toward the depressurizing tank 7 with low atmospheric pressure, and the adsorbent 24 inside the measuring tank 6 is The off gas 27 is used as a carrier to be conveyed to the depressurization tank 7.

The depressurization tank 7 is a decompression tank interposed between the pipeline 4e and the pipeline 4f, and is provided with a filter 23 for discharging only the compressed gas, and a pipeline communicating with the supply port of the adsorption tank 1. 4f is provided. The depressurization tank 7 has an inner diameter
By setting it sufficiently larger than that of e,
The momentum of the compressed gas is attenuated at the time of entering the inside of the depressurizing tank 7, and the off gas 27 is discharged from the pressure equalizing port of the depressurizing tank 7 through the filter 25 to the pressure equalizing system 11 to reduce the internal atmospheric pressure. Let

The pressure equalizing system 11 is a path through which the offgas 27 that is difficult to be adsorbed by the adsorbent 24 flows, and the pressure equalizing system 11 is used.
A pressure equalizing port leading to the tank is provided in every tank in which the adsorbent 24 circulates. The pressure equalizing port eliminates an imbalance in internal pressure generated between the tanks involved in moving the adsorbent 24 and facilitates circulation of the adsorbent 24. , V8, v9, v10, v11, the valves of the tanks involved in the movement of the adsorbent 24 are opened at any time to form a path through which the gas in both tanks circulates and is compressed by the increase of the adsorbent 24. The gas can be delivered to the tank in which the adsorbent 24 is reduced.

As described above, the valves, the compressor 21, the vacuum pump 20, the circulation blower 19, the heater 12, the cooling means and the like of this apparatus are finely controlled by a so-called computer system.

In the present embodiment, as described above, the adsorbent 24, which is said to adsorb several hundred times the volume of carbon dioxide gas 26, is circulated, and a relatively small-scale pipe line and valve can be used. Nevertheless, source gas composition: CO2
15%, N2 67%, O2 18%, raw material gas flow rate: 2 m
3 / h, adsorbent: X-type zeolite, circulation amount: 10 kg /
h, regeneration conditions: measured at 160 ° C. under 50 Torr, removal rate of carbon dioxide from raw material gas: 99%, concentration of recovered carbon dioxide: 95%, which is equal to or better than the conventional fixed tank system. Results were obtained. Of course, by arranging the tanks vertically in the same order as the adsorbent 24 circulates, there is an advantage that free fall due to gravity can be used when the adsorbent 24 circulates. And storage tank 5, measuring tank 6, depressurizing tank 7 and pressure feeding system 1
By providing 0, the adsorbent 24 is efficiently circulated without being stagnant in a part of the circulation path. In addition, the pressure difference and the temperature difference are used together for adsorption and separation, and the adsorbent 24
Since heating and cooling can be performed in different processing tanks, carbon dioxide recovery efficiency is high.

The cooling of the adsorbent 24 also has the purpose of preventing a decrease in the amount of adsorption due to the heat generation of the adsorption reaction, and therefore it is desirable to provide not only in the adsorption tank 1 but also in the purification tank 2 if possible. FIG. 3 shows an example in which the adsorption tank 1 and the purification tank 2 are integrated into a processing tank. By providing a feed port for feeding the raw material gas 25 in the middle part of the tank and a feed port for feeding the carbon dioxide gas 26 at the lower part, the adsorption tank 1 is vertically arranged with the feed port of the raw material gas 25 as a boundary. And a region that fulfills the function of the purification tank 2. In addition to the method of sending the cooled or heated gas into the processing tank, the cooling means and the heater are provided with a pipe through each tank, and the cooled or heated liquid or gas is circulated inside the piping. There are methods, etc. Also, adsorbent 2
In addition to the pressure feeding method used in this embodiment, a belt conveyor or a bucket elevator can be used as the conveying means indispensable for the circulation of No. 4, and this method is effective in suppressing the deterioration of the adsorbent 24 and reducing the conveying power. There is.

The adsorbent used in this embodiment is carbon dioxide gas 26.
Zeolite, which is an inorganic adsorbent, was used for the purpose of adsorbing, but bentonite or oyadite is also present as an equivalent effect can be expected. Further, it is possible to separate and collect other gas by appropriately selecting the adsorbent 24.

[0024]

As described above, by using the gas separation / recovery device according to the present invention, a large valve for switching the gas flow series is not required even in the case of a large scale construction.
A configuration using a relatively small valve is possible. At that time, the valve can be opened and closed promptly and the airtightness of the valve can be increased, the recovery efficiency of carbon dioxide gas can be improved accordingly, and the manufacturing cost and running cost of equipment can be kept low. It is possible to expect remarkable practical effects.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration example of a gas separation and recovery apparatus according to the present invention.

FIG. 2 is an explanatory diagram showing an example of a conventional gas separation and recovery apparatus.

FIG. 3 is a principal part explanatory view showing a modified example of the gas separation and recovery apparatus according to the present invention.

[Explanation of symbols]

 1 Adsorption tank 2 Purification tank 3 Regeneration tank 4 Pipeline 24 Adsorbent 26 Carbon dioxide

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C01B 31/20 B

Claims (2)

[Claims] 1. An adsorption tank for adsorbing a predetermined component to an adsorbent (24) in an apparatus for selectively adsorbing a predetermined component in a mixed gas with an inorganic adsorbent (24) and separating and collecting only a specific gas. 1), a purification tank (2) for separating and discharging components other than the specific gas in the predetermined components adsorbed by the adsorbent (24), and recovering the specific gas from the adsorbent (24) and adsorbing the specific gas. ) And a regeneration tank (3) for regenerating the adsorbent (24) for adsorbing again are arranged in series with the pipe line (4) interposed therebetween to form a circulation path for circulating the adsorbent (24). Characteristic gas separation and recovery device. 2. The gas separation / recovery device according to claim 1, wherein the adsorption tank (1) and the purification tank (2) are integrally provided in line.