JP6733859B2 - Carbon dioxide capture device - Google Patents

Description

The present invention relates to a carbon dioxide recovery device, and more specifically, while recovering carbon dioxide from biogas and exhaust gas and supplying the same to a plant cultivation facility, biogas whose purity has been increased by recovering carbon dioxide The present invention relates to a carbon dioxide recovery device that is supplied as fuel to an internal combustion engine.

Carbon dioxide has been conventionally collected from exhaust gas discharged from a large plant such as a power plant, but recently, as in the technique described in Patent Document 1, an internal combustion engine that drives a generator of a cogeneration system. A carbon dioxide recovery device has been proposed in which carbon dioxide contained in exhaust gas discharged from an engine is recovered and supplied to a plant cultivation facility to improve energy efficiency.

The technique described in Patent Document 1 uses a plant residue after harvest of fruits and the like in a plant cultivation facility as an energy source for driving an internal combustion engine of a cogeneration device, and uses exhaust heat generated by the combustion as a heat source in the cultivation facility. The exhaust gas emitted from the internal combustion engine is pressure-controlled and stored in a carbon dioxide storage tank, and then supplied to a plant cultivation facility.

JP 2005-341953 A

In the technique described in Patent Document 1, the exhaust gas that has passed through the exhaust gas cooling device is adjusted to an appropriate pressure by the compression device, temporarily stored in the carbon dioxide gas storage tank, and then supplied to the cultivation facility. To be done.

In other words, since the carbon dioxide contained in the exhaust gas is not adsorbed and stored in the adsorbent, the recovery efficiency is low and it is necessary to enlarge the storage tank in order to recover a sufficient amount of carbon dioxide. Therefore, there is an inconvenience that the device becomes large.

In addition, the biogas generator removes carbon dioxide from methane (fuel component) that is the main component of biogas and carbon dioxide (non-fuel component) that is a subcomponent, in order to increase the purity of biogas, It is often equipped with a PSA (pressure swing adsorption) device.

Removal of carbon dioxide from biogas and recovery of carbon dioxide from exhaust gas are both carbon dioxide recovery, and having a separate device for that is a good idea in terms of cost and control efficiency. I can not say. Therefore, it is desirable to use the adsorption tank of the carbon dioxide recovery device as the PSA device.

However, conventionally, when driving an engine using biogas, a PSA device is separately provided for high purification of biogas, and another recovery device is installed for recovery of carbon dioxide in exhaust gas. Was there.

Therefore, an object of the present invention is to solve the above-mentioned problems, by using an adsorbent when collecting carbon dioxide generated from a biogas generator and an internal combustion engine of a cogeneration device and supplying it to a plant cultivation facility. Provided is a carbon dioxide recovery device capable of efficiently recovering carbon dioxide without increasing the size of the device and supplying biogas whose purity is increased by recovering carbon dioxide to an internal combustion engine as a fuel. Especially.

In order to solve the above-mentioned problem, in Claim 1, a biogas generator that ferments an organic substance to generate biogas, a cogeneration device having a generator driven by an internal combustion engine, and the biotechnology A carbon dioxide recovery device comprising: a carbon dioxide recovery/supply means for recovering carbon dioxide generated from a gas generator and an internal combustion engine of the cogeneration device and supplying it to a plant cultivation facility. means, a suction tank first adsorbent is accommodated, to feed pressure to the adsorption tank exhaust gas discharged from the internal combustion engine, the first adsorbing carbon dioxide contained in the exhaust gas to the first adsorbent A carbon dioxide adsorbing means, a second carbon dioxide adsorbing means for adsorbing the carbon dioxide contained in the biogas to the first adsorbent by pumping the biogas generated by the biogas generator to the adsorption tank, Carbon dioxide desorption means for decompressing the internal pressure of the adsorption tank to desorb the adsorbed carbon dioxide from the first adsorbent, and biogas pressure-fed to the adsorption tank as fuel to the internal combustion engine. Consisting of biogas supply means, the adsorption tank is connected to the internal combustion engine through a relief valve, and when the exhaust gas filled in the adsorption tank exceeds a set pressure of the relief valve, the exhaust gas is returned to the internal combustion engine as reflux exhaust gas. It is configured to be supplied .

In the carbon dioxide recovery device according to claim 2 , the biogas supply means includes a biogas scavenging means for scavenging the biogas pressure-fed to the adsorption tank, and the biogas scavenged by the biogas scavenging means. The gas was supplied to the internal combustion engine as fuel.

In the carbon dioxide recovery device according to claim 3 , the biogas scavenging means is configured to supply a gas containing at least oxygen to scaveng the biogas pressure-fed to the adsorption tank.

In the carbon dioxide recovery device according to claim 4 , the biogas supply means includes a pressure adjusting mechanism between the adsorption tank and the internal combustion engine, and the biogas pressure-fed to the adsorption tank is used as the pressure. The internal combustion engine is supplied as fuel through an adjusting mechanism.

In the carbon dioxide recovery device according to claim 5 , the biogas supply means is configured to supply the biogas pressure-fed to the adsorption tank from above in the gravity direction of the adsorption tank.

In the carbon dioxide recovery device according to claim 6 , the carbon dioxide recovery/supply means causes the second carbon dioxide adsorption means to adsorb carbon dioxide contained in the biogas to the first adsorbent, The first carbon dioxide adsorbing means is configured to adsorb carbon dioxide contained in the exhaust gas to the first adsorbent.

In the carbon dioxide recovery device according to claim 7, the carbon dioxide recovery/supply means pressure-feeds the desorbed carbon dioxide to a storage tank to adsorb the carbon dioxide to a second adsorbent contained therein. It is configured to have a carbon dioxide storage means for storing .

In the carbon dioxide recovery device according to claim 1, the carbon dioxide recovery/supply means for recovering carbon dioxide generated from the biogas generator and the internal combustion engine of the cogeneration device and supplying it to the plant cultivation facility, a suction tank first adsorbent is accommodated, the exhaust gas discharged from an internal combustion engine to feed pressure adsorption tank, a first carbon dioxide adsorption means for adsorbing the carbon dioxide contained in the exhaust gas to the first adsorbent, Bio The biogas generated by the gas generator is pressure-fed to the adsorption tank to adsorb the carbon dioxide contained in the biogas to the first adsorbent, and the internal pressure of the adsorption tank is reduced to adsorb the biogas. The adsorption tank comprises carbon dioxide desorption means for desorbing carbon dioxide from the first adsorbent, and biogas supply means for supplying the biogas pressure-fed to the adsorption tank to the internal combustion engine as fuel. The adsorption tank is provided with a relief valve. Connected to the internal combustion engine, the exhaust gas filled in the adsorption tank is configured to be supplied as recirculated exhaust gas to the internal combustion engine when the pressure exceeds the set pressure of the relief valve. Energy efficiency can be increased by using it as an electric load or heat source in cultivation facilities, and carbon dioxide can be adsorbed (recovered) using an adsorbent so that carbon dioxide can be efficiently used without increasing the size of the device. Can be recovered.

Furthermore, the biogas generated by the biogas generator is pressure-fed to the adsorption tank so that the carbon dioxide contained in the biogas is adsorbed by the first adsorbent, and the biogas pressure-fed to the adsorption tank. Since it is configured to include a biogas supply means for supplying as a fuel to an internal combustion engine, carbon dioxide recovery from biogas (purification of biogas) and carbon dioxide recovery from exhaust gas can be performed by the same device. Therefore, it is possible to simplify the configuration, reduce the size, and reduce the cost of the entire device. Also, by appropriately changing the size and number of adsorption tanks, the amount of adsorbent, and the like, it is possible to easily construct an apparatus configuration in consideration of a balance between desired biogas purity and cost.

In the carbon dioxide recovery device according to claim 2 , the biogas supply means includes a biogas scavenging means for scavenging the biogas pressure-fed to the adsorption tank, and the biogas scavenged by the biogas scavenging means is internally combusted. Since it is configured to be supplied as fuel to the engine, in addition to the effects described above, the biogas supplied to the internal combustion engine as fuel can be made more highly pure.

In the carbon dioxide recovery device according to claim 3 , since the biogas scavenging means is configured to scavenging the biogas pressure-fed to the adsorption tank by supplying a gas containing at least oxygen, in addition to the above effects. The biogas supplied as a fuel to the internal combustion engine can be made even more highly pure.

In the carbon dioxide recovery device according to claim 4 , the biogas supply means includes a pressure adjusting mechanism between the adsorption tank and the internal combustion engine, and the biogas pressure-fed to the adsorption tank is passed through the pressure adjusting mechanism. Since it is configured to be supplied as fuel to the internal combustion engine, in addition to the above effects, biogas can be supplied as fuel to the internal combustion engine at an appropriate pressure.

In the carbon dioxide recovery device according to claim 5 , since the biogas supply means is configured to supply the biogas pressure-fed to the adsorption tank from above in the gravity direction of the adsorption tank, in addition to the above effects, The carbon dioxide (molecular weight 44) desorbed due to the decrease in the internal pressure of the adsorption tank stays in the lower portion of the adsorption tank shortly before mixing with methane (molecular weight 16), which is the main component of biogas, and hardly mixes there. The biogas supplied can be made even more highly pure.

In the carbon dioxide recovery device according to claim 6 , the carbon dioxide recovery/supply means causes the second carbon dioxide adsorbing means to adsorb the carbon dioxide contained in the biogas to the first adsorbent, and the first carbon dioxide. Since the carbon dioxide contained in the exhaust gas is adsorbed by the first adsorbent by the adsorption means, the carbon dioxide can be more efficiently recovered in addition to the above-mentioned effects.

In the carbon dioxide recovery device according to claim 7 , the carbon dioxide recovery/supply means pressure-feeds the desorbed carbon dioxide to the storage tank, and causes the second adsorbent contained therein to adsorb and store the carbon dioxide. Since it is configured to have a carbon dioxide storage means, in addition to the above-mentioned effects, by adsorbing (storing) carbon dioxide using an adsorbent, it is possible to recover carbon dioxide more efficiently without increasing the size of the device. it can.

It is a schematic diagram which shows the carbon dioxide recovery device which concerns on 1st Embodiment of this invention whole. It is a schematic diagram which shows the cogeneration apparatus of the carbon dioxide recovery apparatus shown in FIG. 1 overall. FIG. 2 is an enlarged explanatory view of a part of the device shown in FIG. 1. It is a sequence diagram which shows operation|movement of the apparatus shown in FIG. It is a sequence diagram similar to FIG. 4 which shows operation|movement of the carbon dioxide recovery apparatus which concerns on 2nd Embodiment of this invention.

Hereinafter, modes for carrying out the carbon dioxide recovery device according to the present invention will be described with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is an overall schematic view of a carbon dioxide recovery device according to a first embodiment of the present invention, and FIG. 2 is an overall schematic view of a cogeneration device constituting the carbon dioxide recovery device shown in FIG. 3 is an enlarged explanatory view of a part of the device shown in FIG.

In FIG. 1, reference numeral 1 indicates a carbon dioxide recovery device. The carbon dioxide recovery device 1 recovers carbon dioxide discharged from the cogeneration device 10 and supplies the carbon dioxide to a plant cultivation facility (hereinafter referred to as “house”) 2 including a greenhouse. In addition, carbon dioxide is also recovered from the biogas generated by the biogas generator 3 provided side by side and supplied to the house 2, and the biogas whose purity is increased by recovering the carbon dioxide is used in the cogeneration device 10 Is configured to be supplied as fuel to. The house 2 is a facility for cultivating plants such as vegetables.

For convenience of understanding, the cogeneration device 10 will be described first with reference to FIG. 2. The cogeneration device 10 includes AC power from a commercial power supply (commercial power system) 12 to an electric load 14 (for example, a lighting fixture of the house 2). A generator (alternator) 20 that can be connected to the power supply path 16 of the internal combustion engine, an internal combustion engine (hereinafter referred to as “engine”) 22 that drives the generator 20, and a heat exchanger 24 that can exchange heat with cooling water of the engine 22. Prepare The generator 20 and the engine 22 are integrated and housed inside the case 28. The commercial power source 12 outputs AC power of 50 Hz or 60 Hz at 100/200 V AC from the single-phase three-wire.

The engine 22 is a water-cooled 4-cycle single-cylinder OHV-type spark ignition type engine that uses biogas containing methane as a main component (hereinafter, simply referred to as “gas”) as a fuel, and has a displacement of 163 cc, for example. The cylinder head of the engine 22 and the cylinder block 22a are arranged in the horizontal direction (sideways) with respect to the case 28, and one piston is reciprocally arranged inside thereof.

The supplied air (intake air) enters the mixer 34 through the intake silencer 30 and the air cleaner 32, and is mixed with the gas supplied from the fuel supply source (not shown) via the gas proportional valve unit 36.

The air-fuel mixture generated by the mixer 34 flows into a combustion chamber (not shown) formed in the lower portion of the cylinder block 22a when an intake valve (not shown) is opened, and is ignited by an ignition plug 22b. When the output of a battery (not shown) is supplied to the ignition plug 22b through an ignition device 22c including a power transistor and an ignition coil, a spark discharge is generated between the electrodes facing the combustion chamber to ignite and burn the air-fuel mixture. ..

Exhaust gas (exhaust gas) generated by combustion flows to an exhaust heat exchanger 22d when an exhaust valve (not shown) is opened, and after exchanging heat with the cooling water of the engine 22 there, the exhaust pipe 38 and the exhaust chamber. It is discharged to the outside of the case 28 (outside the refrigerator) through the (muffler) 40.

As shown in FIG. 3, the exhaust chamber 40 has a labyrinth shape in which plates 40a are alternately projected from the wall surface so as to face each other, and a liquid pool 40b is formed to trap the liquid (moisture) in the exhaust gas as much as possible there. And is discharged to the outside of the system as described later.

A catalyst device 22d1 is integrally arranged in the exhaust heat exchanger 22d, and is configured to remove harmful components in the exhaust gas. As the catalyst device 22d1, one having a characteristic of removing harmful components is selected and used.

An oil tank (oil pan) 22f is formed below the cylinder block 22a of the engine 22, and engine oil (lubricating oil) of the engine 22 is stored therein.

The generator 20 includes a multi-pole coil, is fixed on a crankcase inside a flywheel (not shown) attached to the upper end of the crankshaft, and generates AC power when rotating relative to the flywheel. .. The generator 20 also functions as a starter motor that cranks the engine 22 when energized by the commercial power source 12 (or a battery (not shown)).

The output of the generator 20 is sent to the inverter unit 42, where it is converted into AC100/200V (single phase).

The inverter unit 42 includes a three-phase bridge circuit 42a that rectifies the alternating current output from the generator 20 into a direct current, a booster circuit 42b that boosts the direct current rectified by the three-phase bridge circuit 42a to a predetermined voltage value, and a booster. Inverter (INV) bridge circuit 42c that converts direct current to alternating current, CPU 42d that controls the operation of inverter unit 42, power supply unit 42e, and output destination of inverter bridge circuit 42c are commercial power supply 12 and power generation output during power failure ( A switch 42f that switches between a power outlet 46 used during a power failure and a voltage sensor 42g that detects a voltage between the inverter bridge circuit 42c and the switch 42f.

The switch 42f is switched by an ECU (Electronic Control Unit) 44 that controls the operation of the cogeneration apparatus 10. The ECU 44 comprises a microcomputer having a CPU, ROM, RAM, I/O, counter, indicator, and the like.

The output from the inverter unit 42 is sent to the switchboard 48. The switchboard 48 is a main breaker 48a for preventing overcurrent and the like, a distribution board 48b for supplying the power of the commercial power supply 12 to the output of the inverter unit 42 (connecting it) and supplying it to the electric load 14, A breaker 48c and a current sensor 48d that is arranged in the power feeding path 16 from the commercial power source 12 to the main breaker 48a and outputs a signal according to the current of the AC power flowing therethrough are provided.

The heat exchanger 24 heat-exchanges the medium (water or the like) flowing through the heat source 50 of the house 2 with the cooling water (antifreeze liquid) of the engine 22 flowing through the circulation path 52 on the cogeneration device 10 side to raise the temperature. Specifically, the heat source 50 and the circulation path 52 locally approach each other to form the heat exchanger 24, and the cooling water transfers heat to the heat source 50 of the house 2 to be cooled.

The circulation path 52 connects the engine 22 and the heat exchanger 24, one end is connected to the cooling water outlet 22h of the engine 22, and the other end is connected to the cooling water inlet 22i of the engine 22. Therefore, the cooling water whose temperature has risen through the cylinder block 22a of the engine 22 flows through the circulation path 52, is heat-exchanged by the heat exchanger 24, and is then returned to the engine 22 again. The circulation path 52 is provided with a pump 52a for circulating the cooling water.

The output of the voltage sensor 42g and the like described above is sent to the ECU 44, and the ECU 44 controls the operations of the generator 20 and the engine 22 based on the input sensor output, and also controls the operation of the carbon dioxide recovery device 1 as described later. To do.

Next, the configuration of the carbon dioxide recovery device 1 will be described with reference to FIG.

As shown in the figure, the carbon dioxide recovery device 1 recovers carbon dioxide contained in the exhaust gas discharged from the engine 22 that drives the power generator 20 of the cogeneration device 10 described above, while it is generated by the biogas generator 3 provided side by side. Carbon dioxide is also recovered from the biogas that is generated and supplied to the house 2 for cultivating plants such as vegetables, and two adsorption tanks 60a and 60b (collectively referred to as "adsorption tank 60") are provided. The individual storage tanks 62 are provided.

First, specifically describing the exhaust gas flow, the exhaust chamber 40 of the engine 22 is connected to the adsorption tank 60 via the first conduit 64 (and its branch pipe 64a), and the adsorption tank 60 is connected to the second tank. It is connected to the storage tank 62 via a conduit 66 (and its branch pipe 66a). Exhaust gas or carbon dioxide contained in the exhaust gas is supplied to the house 2 from the exhaust chamber 40 of the engine 22 through the first conduit 64, the adsorption tank 60, the second conduit 66, the storage tank 62, and the third conduit 70.

Thus, the adsorption tank 60, more specifically the adsorption tanks 60a and 60b, is arranged downstream in the flow of the exhaust gas discharged from the exhaust chamber 40 of the engine 22, and the storage tank 62 is arranged further downstream of the adsorption tank 60. To be done.

Although not shown, the adsorption tank 60 has an internal space divided into a large number of small chambers by shelves, through which exhaust gas flows, and an adsorbent (hereinafter referred to as “first adsorbent”) in each chamber. 72 is configured to be accommodated.

The first adsorbent 72 is formed by pelletizing Haskley (trade name), and is housed in a net or the like for each predetermined number or weight of pellets, and is placed in each chamber.

In the storage tank 62, the internal space is divided into a large number of small chambers by shelves, and the desorbed carbon dioxide flows therethrough, and an adsorbent (hereinafter referred to as “second adsorbent”) 74 is provided in each of the chambers. Configured to be housed. The second adsorbent 74 is also formed by pelletizing Haskley (trade name), and is housed in a net or the like for each predetermined number or weight of pellets, and is placed in each chamber. The first adsorbent 72 and the second adsorbent 74 may be of any type as long as they can adsorb carbon dioxide sufficiently according to pressure changes.

A first three-way valve 76, a first dehumidifying tank 78, a first compressor 80, a second three-way valve 82, a first drying section 84 are provided in the first conduit 64 (and its branch pipe 64a) from the upstream side in the flow of exhaust gas. The first and second opening/closing valves 86, 90 are arranged, and the first drying section 84 is connected to the upstream side of the first dehumidification tank 78 by a bypass pipe 92. A third opening/closing valve 94 is arranged in the bypass pipe 92.

In the second conduit 66 (and its branch pipe 66a) from the upstream side in the flow of exhaust gas, the fourth and fifth on-off valves 96 and 100, the buffer tank 102, the third three-way valve 103, the second compressor 104, and the second dryer. The unit 106 is arranged. The second conduit 66 and its branch pipe 66a are opened via the first and second relief valves (check valves) 110 and 112 on the upstream side of the fourth and fifth on-off valves 96 and 100.

The sixth opening/closing valve 114 is arranged in the third conduit 70, and the downstream side of the storage tank 62 is the upstream side of the sixth opening/closing valve 114 and the second and third bypass pipes 116 and 120 of the adsorption tank 60. It is connected to the upstream side. Seventh and eighth on-off valves 122 and 124 are arranged in the second and third bypass pipes 116 and 120.

The first, second, and third three-way valves 76, 82, 103 are electromagnetic control valves, operate according to a command from the ECU 44, and allow the exhaust gas flowing from the upstream to flow to either the downstream side or the atmosphere, or to release the atmosphere. It is configured to be introduced and flow downstream. By disposing the second three-way valve 82 downstream of the first compressor 80, the exhaust gas containing water can be discharged to the atmosphere without passing through the first drying section 84. ..

The 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th on-off valves 86, 90, 94, 96, 100, 114, 122, 124 are also electromagnetic control valves, and commands of the ECU 44. It is configured so that the gas flowing from the upstream flows or does not flow to the downstream.

Like the adsorption tank 60 and the storage tank 62, the first dehumidifying tank 78 has an internal space divided into a large number of small chambers by shelves through which exhaust gas flows and a desiccant made of silica gel or the like in each chamber. It is contained and configured to be dehumidified as the gas passes through.

The first and second compressors 80, 104 are supplied and driven by the output of the generator 20 of the cogeneration system 10, more specifically, the output of the generator 20 generated by the inverter unit 42, and supplied from the upstream. The gas is compressed and discharged downstream, but when not driven, the gas does not flow. As a result, the first and second compressors 80, 104 are configured to operate by being supplied with stable power regardless of the load of the engine 22 of the cogeneration system 10.

Inside the first and second drying sections 84 and 106, a mixture of unsaturated polyester resin and various fillers, a curing initiator, etc. is impregnated into a mat-shaped glass fiber, and a desiccant such as silica gel is added to the glass fiber. Is arranged so that the exhaust gas passes through it to be dehumidified.

The buffer tank 102 arranged in the second conduit 66 is for preventing an excessive negative pressure on the upstream side when the second compressor 104 operates, and is provided with a filter or a maze inside. When the first adsorbent 72 should be damaged, the fragments are prevented from being sucked by the second compressor 104 and the pressure on the suction side of the second compressor 104 is prevented from becoming an excessive negative pressure. ..

Explaining the first and second relief valves 110 and 112 arranged in the second conduit 66 and its branch pipe 66a, the first and second relief valves 110 and 112 are further branched from the second conduit 66 and its branch pipe 66a. The second branch pipes 661 and 66a1 are arranged.

In the second branch pipe 661, a venturi portion 6611 is formed between the position where the first relief valve 110 is arranged and the tip (open end) 6610. As shown in FIG. 3, the venturi portion 6611 is connected to the liquid pool 40b of the exhaust chamber 40 via a pipe 6612 and an opening/closing valve 6613 arranged therein. The on-off valve 6613 may be removed.

As a result, when the pressure of the exhaust gas filled in the adsorption tank 60a exceeds the set pressure of the first relief valve 110, for example, about 0.7 MPa, part of the exhaust gas pushes the first relief valve 110 open to the venturi portion 6611. Inflow. In the venturi portion 6611, the water trapped in the liquid pool 40b is sucked by the negative pressure generated by the increase in the flow velocity and is discharged from the tip 6610 of the second branch pipe 661 to the atmosphere.

Further, as shown in FIG. 1, the second branch pipe 66a1 of the branch pipe 66a is configured to be connected to the engine 22. That is, when the pressure of the exhaust gas filled in the adsorption tank 60a exceeds the set pressure of the relief valve 112, for example, about 0.7 MPa, a part of the exhaust gas pushes the relief valve 112 open and flows through the second branch pipe 66a1. It is supplied to the intake silencer 30 of 22 or the exhaust port downstream of the exhaust valve of the combustion chamber as EGR (Exhaust Gas Recirculation), more specifically as external EGR or internal EGR (Air Injection), and is configured to enhance energy efficiency. Note that the second branch pipe 66a1 may be provided with a venturi portion similarly to the branch pipe 66a.

A dehumidifier 130 is arranged between the cogeneration system 10 and the house 2. The dehumidifier 130 has a structure similar to that of the first and second drying units 84 and 106, and includes a sheet mixed with a desiccant such as silica gel, through which air containing moisture in the house 2 flows to dehumidify. The dehumidified and dehumidified air returns to the house 2 again.

In the dehumidifier 130, the desiccant after dehumidification is regenerated by heat exchange with heated cooling water or exhaust gas from the engine 22. Further, as described above, the medium (water or the like) flowing through the heat source 50 of the house 2 is heat-exchanged with the cooling water of the engine 22 flowing through the circulation path 52 on the commercial power source 12 side to raise the temperature.

Next, focusing on the flow of biogas, the biogas generator 3 is connected to the adsorption tank 60 via the fourth conduit 126 and the first conduit 64 (and its branch pipe 64a). .. The adsorption tank 60 is connected to the engine 22 that drives the generator 20 of the cogeneration system 10 via the second conduit 66 (and its branch pipe 66a) and the fifth conduit 128.

The biogas generator 3 is, for example, a device that ferments an organic waste to produce a gaseous substance (biogas) containing methane as a main component. The produced biogas contains a large amount of carbon dioxide (non-fuel component) in addition to methane (fuel component).

The biogas generated by the biogas generator 3 is supplied to the engine 22 as fuel through the fourth conduit 126, the first conduit 64, the adsorption tank 60, the second conduit 66, and the fifth conduit 128. The fourth conduit 126 joins the first conduit 64 downstream of the third drying section 142 and upstream of the branch pipe 64a of the first conduit 64. Further, the fifth conduit 128 branches from the second conduit 66 downstream of the branch pipe 66 a of the second conduit 66 and upstream of the buffer tank 102.

Thus, the adsorption tank 60 is arranged downstream in the flow of biogas generated by the biogas generator 3, and the engine 22 is arranged further downstream of the adsorption tank 60.

A fourth three-way valve 134, a second dehumidification tank 136, a third compressor 138, a fifth three-way valve 140, and a third drying section 142 are arranged in the fourth conduit 126 from the upstream side in the flow of biogas, and The 3rd drying part 142 is connected to the upstream side of the 2nd dehumidification tank 136 by the bypass pipe 144. A ninth opening/closing valve 146 is arranged in the bypass pipe 144. Further, a tenth opening/closing valve 148 and a pressure adjusting mechanism 150 are arranged in the fifth conduit 128 from the upstream side in the flow of biogas.

The fourth and fifth three-way valves 134 and 140 are also electromagnetic control valves and operate in response to a command from the ECU 44 to allow biogas flowing from the upstream to flow to either the downstream side or the atmosphere, or to introduce the atmosphere to the downstream side. It is configured to flow to. Further, by disposing the fifth three-way valve 140 downstream of the third compressor 138, the biogas containing water can be released to the atmosphere without passing through the third drying section 142. Composed.

The second dehumidifying tank 136, the third compressor 138, and the third drying unit 142 also have the same configuration as the first dehumidifying tank 78, the first and second compressors 80 and 104, and the first and second drying units 84 and 106. To be done. The ninth and tenth on-off valves 146 and 148 are also electromagnetic control valves, and are configured to operate in response to a command from the ECU 44 and to flow/do not flow the gas flowing from the upstream.

A pressure adjusting mechanism 150 for adjusting the pressure of biogas supplied to the engine 22 is inserted in the fifth conduit 128, and the pressure of biogas supplied from the adsorption tank 60 is adjusted and supplied to the engine 22. To do.

The pressure adjusting mechanism 150 is composed of a pressure adjusting valve, operates according to a command from the ECU 44, and adjusts (depressurizes) the pressure of the biogas flowing from the upstream side to flow the biogas to the engine 22 side.

Next, the operation of the carbon dioxide recovery device 1 will be described with reference to the sequence diagram of FIG. This operation is specifically executed by the ECU 44 of the cogeneration system 10.

Explaining below, SEQ. 1 (second carbon dioxide adsorbing means) is an adsorption (recovery) mode of carbon dioxide contained in biogas, and biogas generated by the biogas generator 3 is pressure-fed to the adsorption tank 60 to be filled therein. The biogas is highly purified by adsorbing and collecting carbon dioxide contained in the biogas filled in the first adsorbent 72. In the following description, the case where the adsorption tank 60a is used as the adsorption tank 60 will be described as an example.

SEQ. In No. 1, the fourth three-way valve 134 is operated to flow the gas to the downstream second dehumidification tank 136, the power of the generator 20 is supplied to turn on (drive) the third compressor 138, and the fifth three-way valve The valve 140 is operated to flow the gas to the downstream third drying section 142, and the ninth opening/closing valve 146 is closed to flow the biogas to the downstream adsorption tank 60a.

SEQ. In No. 1, by further opening the first opening/closing valve 86 and closing the second, fourth and seventh opening/closing valves 90, 96, 122, the biogas from which water has been removed by the third drying section 142 or the like is removed. The carbon dioxide contained in the biogas is adsorbed to the first adsorbent 72 by being fed under pressure by the third compressor 138 and supplied to the adsorption tank 60a.

That is, the pressure inside the adsorption tank 60a is increased to the set pressure of the first relief valve 110 (about 0.7 MPa), and carbon dioxide is adsorbed to the first adsorbent 72 under the pressure. At this time, since the gas is continuously supplied, the carbon dioxide partial pressure in the adsorption tank 60a does not decrease due to the adsorption, so that the carbon dioxide can be recovered with high efficiency.

SEQ. 2 (biogas releasing means) is a release (supply) mode of the biogas filled in the adsorption tank 60a, and is filled in the adsorption tank 60a, and carbon dioxide is adsorbed (recovered) by the first adsorbent 72. Releases biogas with increased purity.

SEQ. In No. 2, the fourth, seventh and tenth on-off valves 96, 122 and 148 are opened, the first and sixth and eighth on-off valves 86, 114 and 124 are closed, and the third three-way valve 103 is connected to the downstream second gas. The biogas with which the adsorption tank 60a is filled is discharged by supplying the gas to the compressor 104 and turning off the second compressor 104, and the biogas is supplied to the engine 22 via the pressure adjusting mechanism 150.

The biogas in the adsorption tank 60a is filled in the adsorption tank 60a at the set pressure (about 0.7 MPa) of the first relief valve 110 and is supplied to the engine 22 by releasing this pressure. 150 reduces the supply pressure to a pressure suitable for supply to the engine 22.

In the biogas release described above, a part of the carbon dioxide adsorbed on the first adsorbent 72 is desorbed and released together with the biogas due to the decrease in the internal pressure of the adsorption tank 60a. The decrease of the internal pressure of the tank 60a is suppressed (for example, it is not decreased to the atmospheric pressure).

SEQ. 3 (first carbon dioxide adsorbing means) is an adsorption (recovery) mode of carbon dioxide contained in the exhaust gas, and the exhaust gas discharged from the engine 22 is pressure-fed to the adsorption tank 60a and filled therein, and the adsorption tank 60a is filled with the exhaust gas. The carbon dioxide contained in the exhaust gas is adsorbed by the first adsorbent 72 and collected.

SEQ. In No. 3, the first three-way valve 76 is operated so as to flow the gas to the first dehumidifying tank 78 on the downstream side, the power of the generator 20 is supplied to turn on the first compressor 80, and the second three-way valve 82 is turned on. The gas is operated so as to flow to the first drying section 84 on the downstream side, and the third opening/closing valve 94 is closed to flow the exhaust gas to the adsorption tank 60a on the downstream side.

SEQ. In No. 3, by further opening the first on-off valve 86 and closing the second, fourth and seventh on-off valves 90, 96, 122, the exhaust gas from which moisture has been removed by the first drying section 84 or the like is removed. 1 The compressor 80 pumps it to fill the adsorption tank 60a, and the carbon dioxide contained in the exhaust gas is adsorbed by the first adsorbent 72.

SEQ. 1 and SEQ. The adsorption process of No. 3 may be performed sequentially, but may be performed in parallel in each of a plurality of adsorption tanks 60 provided. When the adsorption tanks 60 are executed in parallel, it is possible to continuously flow the biogas and the exhaust gas.

SEQ. 4 is a scavenging mode of the exhaust gas filled in the adsorption tank 60a. The exhaust gas pressure-fed and filled in the adsorption tank 60a in 3 is scavenged by the carbon dioxide filled in the storage tank 62 as described later.

SEQ. In No. 4, the seventh on-off valve 122 is opened, the first, fourth, sixth and eighth on-off valves 86, 96, 114, 124 are closed, and the second compressor 104 is turned off. The exhaust gas filled in the adsorption tank 60a is scavenged with the carbon dioxide filled in the storage tank 62.

As will be described later, the storage tank 62 is filled with carbon dioxide at, for example, about 1.0 MPa. Therefore, a part of the carbon dioxide filled in the storage tank 62 is stored in the adsorption tank 60a until the internal pressures of the storage tank 62 and the adsorption tank 60a decrease to the set pressure (about 0.7 MPa) of the first relief valve 110. The inflowing gas is discharged from the first relief valve 110, and the exhaust gas containing harmful components filled in the adsorption tank 60a is scavenged.

SEQ. 1 and SEQ. The adsorption process of No. 3 can be performed continuously to increase the adsorption amount of carbon dioxide to the first adsorbent 72 and increase the recovery amount of carbon dioxide. 2 and SEQ. SEQ. The scavenging process of 4 may be executed.

SEQ. 5 (carbon dioxide desorption means, carbon dioxide storage means) is a desorption and storage mode of the adsorbed carbon dioxide, and decompresses the internal pressure of the adsorption tank 60a to desorb the carbon dioxide adsorbed by the first adsorbent 72. It is separated and pressure-fed to the storage tank 62 to be adsorbed by the second adsorbent 74 and stored.

SEQ. In No. 5, the fourth on-off valve 96 is opened, the third three-way valve 103 is operated so as to flow the gas to the downstream second compressor 104, and the power of the generator 20 is supplied to operate the second compressor 104. While turning on, the first, fifth, sixth, seventh, eighth and tenth on-off valves 86, 100, 114, 122, 124, 148 are closed.

As a result, the pressure inside the adsorption tank 60a is reduced by the second compressor 104, the pressure inside the storage tank 62 is increased, and the carbon dioxide adsorbed by the first adsorbent 72 in the adsorption tank 60a is absorbed. Is detached. The desorbed carbon dioxide is dehumidified in the second drying unit 106, then pressure-fed to the storage tank 62 by the second compressor 104, and adsorbed and stored in the second adsorbent 74 of the storage tank 62.

More specifically, the carbon dioxide adsorbed on the first adsorbent 72 is desorbed by reducing the pressure inside the adsorption tank 60a to the atmospheric pressure or less by the second compressor 104.

The pressure inside the storage tank 62 is SEQ. Since the set pressure (about 0.7 MPa) of the relief valve 110 is obtained by the scavenging process of No. 4, the carbon dioxide desorbed by the second compressor 104 is supplied to further increase, for example, 1.0 MPa. Pressurized to the extent.

In this way, the pressure during storage in the storage tank 62 is increased to a pressure higher than the pressure during adsorption in the adsorption tank 60, so the desorbed carbon dioxide is reliably stored in the storage tank 62. can do. It is desirable that the second adsorbent 74 in the storage tank 62 be stored in a sufficiently larger amount than the first adsorbent 72 in the adsorption tank 60.

SEQ. 1 to SEQ. The processes up to 5 are repeatedly executed according to the carbon dioxide storage capacity (adsorption capacity) of the storage tank 62, but only biogas is allowed to flow into the adsorption tank 60a and SEQ. Only 1, 2, 5 may be repeatedly executed, and only the exhaust gas is caused to flow to the adsorption tank 60a and the SEQ. Only steps 3, 4 and 5 may be repeated.

In addition, only the biogas is allowed to flow into the adsorption tank 60a and the SEQ. Only the exhaust gas is flowed to the adsorption tank 60b while executing only 1, 2, 5 and SEQ. Only 3, 4, 5 may be executed.

Further, a plurality of adsorption tanks 60a, 60b, 60c, 60d are provided, and biogas is flown alternately to the adsorption tanks 60a and 60b to generate SEQ. 1 and SEQ. 2 and 5 are alternately executed, while exhaust gas is alternately flown to the adsorption tank 60c and the adsorption tank 60d, and SEQ. 3 and SEQ. You may perform 4 and 5 by turns. When a plurality of adsorption tanks 60 are provided, it is necessary to add appropriate configurations such as an on-off valve and a switching valve.

SEQ. 6 is a release (supply) mode of the stored carbon dioxide, which releases the internal pressure of the storage tank 62 to desorb the carbon dioxide adsorbed by the second adsorbent 74 and release it to the house 2.

SEQ. At 6, the sixth on-off valve 114 is opened, the seventh and eighth on-off valves 122 and 124 are closed, and the second compressor 104 is turned off. Thereby, the carbon dioxide adsorbed (stored) on the second adsorbent 74 of the storage tank 62 is released and flows into the house 2 as it is.

At this time, since the carbon dioxide in the storage tank 62 is stored at, for example, about 1.0 MPa, it can be easily supplied to the house 2 simply by opening the sixth opening/closing valve 114. Further, by providing an appropriate guide pipe, it is possible to pinpointly supply a desired plant in the plant group of the house 2.

As described above, the carbon dioxide recovery device 1 according to the first embodiment is an adsorption tank for absorbing carbon dioxide contained in the exhaust gas discharged from the engine 22 of the cogeneration device 10 and the biogas generated by the biogas generation device 3. Since it is configured to be collected by adsorption/desorption to the first adsorbent 72 (second adsorbent 74) housed in 60 (storage tank 62) and supplied to the house 2, it is generated by the cogeneration device 10. Energy efficiency can be improved by using electric power and exhaust heat for the electric load and heat source of the house 2 and the efficiency of carbon dioxide can be improved without adsorbing carbon dioxide by using an adsorbent. Can be collected.

Further, since the biogas whose purity has been increased by recovering carbon dioxide is supplied to the engine 22 as a fuel, carbon dioxide recovery from biogas (purification of biogas) and dioxide from exhaust gas are performed. Carbon recovery can be performed by the same device, and the overall structure of the device can be simplified, downsized, and cost reduced. Furthermore, by appropriately changing the size and number of the adsorption tank 60, the amount of the adsorbent, and the like, it is possible to easily construct an apparatus configuration in consideration of a desired biogas purity and cost balance.

Further, since the biogas filled in the adsorption tank 60 is discharged and supplied to the engine 22 as fuel, the propulsive force for supplying the biogas to the engine 22 as fuel is only the internal pressure of the adsorption tank 60. Therefore, the entire device can be simplified.

In addition, since the biogas filled in the adsorption tank 60 is configured to be supplied to the engine 22 as fuel via the pressure adjusting mechanism 150, the biogas can be supplied to the engine 22 as fuel at an appropriate pressure.

In addition, since the biogas filled in the adsorption tank 60 is configured to be supplied as fuel from the upper portion of the adsorption tank 60 to the engine 22, the carbon dioxide (molecular weight 44) desorbed due to the decrease in the internal pressure of the adsorption tank 60 is the biogas. The biogas supplied as a fuel to the engine 22 can be made higher in purity because it stays in the lower portion of the adsorption tank 60 shortly after mixing with methane (molecular weight 16) as the main component and hardly mixes.

(Second embodiment)
FIG. 5 is a sequence diagram similar to FIG. 4, showing the operation of the carbon dioxide recovery device according to the second embodiment of the present invention.

Explaining focusing on the points different from the first embodiment, in the second embodiment, the biogas filled in the adsorption tank 60a is supplied by scavenging.

SEQ. 2a (biogas scavenging means) is a scavenging (supply) mode of the biogas filled in the adsorption tank 60a, is filled in the adsorption tank 60a, and carbon dioxide is adsorbed (recovered) by the first adsorbent 72. Purified biogas is scavenged with a gas containing at least oxygen, more specifically with the atmosphere.

SEQ. In 2a, the 4th and 10th on-off valves 96 and 148 are opened, the 1st and 7th on-off valves 86 and 122 are closed, and the 3rd three-way valve 103 is operated so as to allow the atmosphere to flow to the downstream second compressor 104. At the same time, the power of the generator 20 is supplied to turn on the second compressor 104. As a result, the atmosphere introduced from the third three-way valve 103 is pressure-fed to the adsorption tank 60a by the second compressor 104 to scavenge the biogas filled therein and supply it to the engine 22 via the pressure adjusting mechanism 150. ..

Since the carbon dioxide recovery device 1 according to the second embodiment is configured to scavenge at least oxygen-containing gas, more specifically, biogas in the atmosphere and supply the biogas as fuel to the engine 22, the internal pressure of the adsorption tank 60a is reduced. Since the carbon dioxide adsorbed on the first adsorbent 72 does not decrease and the carbon dioxide adsorbed on the first adsorbent 72 does not desorb, the biogas supplied as fuel to the engine 22 can be highly purified. The remaining structure and effects are the same as those of the first embodiment.

As described above, in the first and second embodiments of the present invention, the biogas generator 3 that ferments organic matter to generate biogas, and the generator (alternator) driven by the internal combustion engine (engine) 22. ) 20 and the biogas generator 3, and the carbon dioxide generated from the internal combustion engine (engine) 22 of the cogeneration device 10 is collected and supplied to the plant cultivation facility (house) 2. In the carbon dioxide recovery device 1 including the carbon dioxide recovery/supply means, the carbon dioxide recovery/supply means is discharged from the adsorption tank 60 containing the first adsorbent 72 and the internal combustion engine (engine) 22. It feed pressure to that gas to the adsorption tank 60, the first carbon dioxide adsorption means the carbon dioxide contained in the exhaust gas is adsorbed to the first adsorbent 72 (ECU44, SEQ.3) and the biogas generator 3 Second carbon dioxide adsorbing means (ECU 44, SEQ.1) for adsorbing the carbon dioxide contained in the biogas to the adsorption tank 60 by pressure-feeding the biogas generated in step (ECU44, SEQ.1), A carbon dioxide desorption means (ECU44, SEQ.5) for decompressing the internal pressure of the tank 60 to desorb the adsorbed carbon dioxide from the first adsorbent 72, and a biogas pressure-fed to the adsorption tank 60. The adsorption tank 60 is connected to the internal combustion engine (engine) 22 via a relief valve 112 and is filled in the adsorption tank 60. When the exhaust gas exceeds the preset pressure of the relief valve 112, the exhaust gas is supplied to the internal combustion engine (engine) 22 as recirculation exhaust gas. Energy efficiency can be increased by using it as an electric load or heat source in cultivation facilities, and carbon dioxide can be adsorbed (recovered) using an adsorbent so that carbon dioxide can be efficiently used without increasing the size of the device. Can be recovered.

Further, the second carbon dioxide adsorbing means (ECU44, SEQ.1) for sending the biogas generated by the biogas generator 3 to the adsorption tank 60 under pressure to adsorb the carbon dioxide contained in the biogas onto the first adsorbent 72. And a biogas supply means for supplying the biogas pressure-fed to the adsorption tank 60 to the internal combustion engine (engine) 22 as a fuel. Therefore, carbon dioxide recovery from the biogas (purification of biogas) Also, carbon dioxide recovery from exhaust gas can be performed by the same device, and the overall structure of the device can be simplified, downsized, and cost reduced. In addition, by appropriately changing the size and number of the adsorption tank 60, the amount of the adsorbent, and the like, it is possible to easily construct a device configuration in consideration of the balance between desired biogas purity and cost.

Further, in the first embodiment, the biogas supply means includes biogas release means (ECU44, SEQ.2) for releasing the biogas pressure-fed to the adsorption tank 60, and the biogas release means. Since the biogas released by the (ECU 44, SEQ.2) is configured to be supplied to the internal combustion engine (engine) 22 as fuel, the biogas is supplied to the internal combustion engine (engine) 22 as fuel. Since only the internal pressure of the adsorption tank 60 is the driving force for doing so, the entire apparatus can be simplified.

Further, in the second embodiment, the biogas supply means includes biogas scavenging means (ECU44, SEQ.2a) for scavenging the biogas pressure-fed to the adsorption tank 60, and the biogas scavenging means. Since the biogas scavenged by the (ECU 44, SEQ. 2a) is configured to be supplied to the internal combustion engine (engine) 22 as a fuel, the biogas supplied to the internal combustion engine (engine) 22 as a fuel in addition to the above effects. Can be of higher purity.

Further, since the biogas scavenging means (ECU 44, SEQ. 2a) is configured to scavenge the biogas pressure-fed to the adsorption tank 60 by supplying a gas containing at least oxygen, internal combustion The biogas supplied to the engine 22 as fuel can be made even more highly pure.

Further, in the first and second embodiments, the biogas supply unit includes a pressure adjusting mechanism 150 between the adsorption tank 60 and the internal combustion engine (engine) 22, and pressure-feeds to the adsorption tank 60. Since the configured biogas is supplied as fuel to the internal combustion engine (engine) 22 through the pressure adjusting mechanism 150, in addition to the above-described effects, the biogas is supplied to the internal combustion engine (engine) 22 at an appropriate pressure. It can be supplied as fuel.

Further, since the biogas supply means is configured to supply the biogas pressure-fed to the adsorption tank 60 from above in the gravity direction of the adsorption tank 60, the internal pressure of the adsorption tank 60 is reduced in addition to the above effect. The desorbed carbon dioxide (molecular weight 44) stays in the lower part of the adsorption tank 60 shortly before mixing with methane (molecular weight 16) which is the main component of biogas, and is hardly mixed, so that it is supplied to the internal combustion engine (engine) 22 as fuel. The biogas used can be made even more highly pure.

Further, the carbon dioxide recovery/supply means causes the second carbon dioxide adsorption means (ECU 44, SEQ.1) to adsorb carbon dioxide contained in the biogas to the first adsorbent 72, and Since the carbon adsorbing means (ECU 44, SEQ.3) is configured to adsorb the carbon dioxide contained in the exhaust gas to the first adsorbent 72, the carbon dioxide can be more efficiently recovered in addition to the above effects. it can.

Further, the carbon dioxide recovery/supply means pressure-feeds the desorbed carbon dioxide to a storage tank and causes the second adsorbent contained therein to adsorb and store the carbon dioxide (ECU44, SEQ.5). In addition to the effects described above, by adsorbing (storing) carbon dioxide using an adsorbent, the carbon dioxide can be more efficiently recovered without increasing the size of the device.

In the first and second embodiments, the displacement of the engine 22 and the like are shown as specific values, but the present invention is not limited to these. Further, the biogas containing methane as a main component has been exemplified, but another substance may be contained as a main component as long as it contains carbon dioxide as a secondary component.

1 carbon dioxide recovery device, 2 house (plant cultivation facility), 3 biogas generator, 10 cogeneration device, 14 electric load, 20 generator, 22 engine (internal combustion engine), 44 ECU (electronic control unit. carbon dioxide recovery /Supply means, first and second carbon dioxide adsorption means, carbon dioxide desorption means, biogas supply means, biogas release means, biogas scavenging means, carbon dioxide storage means), 60 adsorption tank, 62 storage tank, 64 , 66, 70, 126, 128 1st, 2nd, 3rd, 4th, 5th conduit, 6611 Venturi part, 72, 74 1st, 2nd adsorbent, 76, 82, 103, 134, 140 1st , 2nd, 3rd, 4th, 5th three-way valve, 78, 136 1st, 2nd dehumidification tank, 80, 104, 138 1st, 2nd, 3rd compressor, 84, 106, 142 1st, 2nd, 3rd drying part, 86, 90, 94, 96, 100, 114, 122, 124, 146, 148 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th , 9th and 10th on-off valves, 92, 116, 120, 144 bypass pipe, 110, 112 relief valve, 130 dehumidifier, 150 pressure adjusting mechanism

Claims (7)

A biogas generator that ferments organic matter to produce biogas, a cogeneration device that has a generator driven by an internal combustion engine, and dioxide that is generated from the biogas generator and the internal combustion engine of the cogeneration device. In a carbon dioxide recovery device comprising a carbon dioxide recovery/supply means for recovering carbon and supplying it to a plant cultivation facility,
The carbon dioxide recovery/supply means is
An adsorption tank containing a first adsorbent,
It feed pressure of exhaust gas discharged from the internal combustion engine to the suction tank, and the first carbon dioxide adsorption means for adsorbing the carbon dioxide contained in the exhaust gas to the first adsorbent,
Second carbon dioxide adsorbing means for pressure-feeding the biogas generated by the biogas generator to the adsorption tank to adsorb carbon dioxide contained in the biogas to the first adsorbent,
Carbon dioxide desorption means for reducing the internal pressure of the adsorption tank to desorb the adsorbed carbon dioxide from the first adsorbent,
Consisting of biogas supply means for supplying the internal combustion engine with biogas pressure-fed to the adsorption tank as fuel,
The adsorption tank is connected to the internal combustion engine via a relief valve, and is configured to be supplied as recirculation exhaust gas to the internal combustion engine when the exhaust gas filled in the adsorption tank exceeds a set pressure of the relief valve. A carbon dioxide recovery device characterized in that The biogas supply means comprises a biogas scavenging means for scavenging the biogas pressure-fed to the adsorption tank, and supplies the biogas scavenged by the biogas scavenging means to the internal combustion engine as fuel. The carbon dioxide recovery device according to claim 1. The carbon dioxide recovery device according to claim 2, wherein the biogas scavenging means supplies a gas containing at least oxygen to scaveng the biogas pressure-fed to the adsorption tank. The biogas supply means includes a pressure adjusting mechanism between the adsorption tank and the internal combustion engine, and supplies the biogas pressure-fed to the adsorption tank as fuel to the internal combustion engine via the pressure adjusting mechanism. The carbon dioxide recovery device according to any one of claims 1 to 3, characterized in that. The carbon dioxide recovery device according to any one of claims 1 to 4, wherein the biogas supply unit supplies the biogas pressure-fed to the adsorption tank from above in the gravity direction of the adsorption tank. The carbon dioxide recovery/supply means causes the carbon dioxide contained in the biogas to be adsorbed by the first adsorbent by the second carbon dioxide adsorbing means, and the carbon dioxide contained in the exhaust gas by the first carbon dioxide adsorbing means. 6. The carbon dioxide recovery device according to claim 1, wherein carbon is adsorbed on the first adsorbent. The carbon dioxide recovery/supply means includes a carbon dioxide storage means for pumping the desorbed carbon dioxide to a storage tank and adsorbing the desorbed carbon dioxide to a second adsorbent accommodated therein for storage. Item 7. The carbon dioxide recovery device according to any one of items 1 to 6.

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