JP2012026342A - Co2 recovery type power generation system and its operation control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control technology at start and stop of a COrecovery type power generation system, which achieves CO-free cogeneration, and which separates and recoveries COin engine exhaust gas without discharging COinto the atmosphere.SOLUTION: The system secures highly concentrated COgas delivery to a COrecovery pipeline 6c while realizing stable start and stop by properly operating an EGR gas flow valve 5b, intake three-way valve 5e, or exhaust three-way valve 6d at start or stop of an engine on the basis of COconcentration in exhaust gas.

Description

  TECHNICAL FIELD The present invention relates to a power generation system, and in particular, an operation at startup and stop of a CO2 recovery type power generation system that enables power generation and heat recovery while separating and recovering CO2 in engine exhaust gas and enables CO2-free cogeneration. It relates to control technology.

Conventionally, in a power generation system or a cogeneration system that uses an engine as a driving source, engine exhaust gas is generally discharged into the atmosphere. However, in recent years, prevention of global warming has been screamed, and reduction of CO2 emissions has become a global issue, and therefore, CO2 reduction of exhaust gas is also required in this field.
The inventor of the present application has proposed a technique for separating and recovering CO2 and immobilizing it in a cogeneration system using biomass as a fuel for this problem (Patent Document 1).
In this technique, as shown in FIG. 8, biomass fuel and pure oxygen are premixed by a mixer (mixer) 102 and supplied to the gas engine 101, and this is used as a drive source to generate electricity and supply power. . Further, by using pure oxygen as the oxidant, the exhaust gas that is only CO2 and H2O is cooled in the heat exchanger 105 to remove the H2O component. As a result, CO2 can be efficiently recovered and heat can be supplied by recovering heat from the exhaust gas. Further, the CO 2 gas that has passed through the heat exchanger 105 is compressed by a compressor 107 driven by a motor 106 and pumped to the underground injection well 108. The above flow enables CO2 free electric power and heat co-supply.

JP 2010-13333 A

In the above system that uses pure oxygen as the oxidant, it is necessary to switch to air supply at startup and shutdown, or to introduce air for purging. However, sudden changes in the composition of the supply gas worsen combustion in the engine. Damage to the engine and the CO2 compressor. In addition, since the CO2 concentration in the exhaust gas decreases, the compression efficiency when boosting the CO2 decreases.
Furthermore, when adopting a system that pumps to the CO2 recovery pipeline as a method of processing the recovered CO2, a decrease in the CO2 concentration means that an impure gas is mixed into the pipeline, and in addition to a decrease in the processing efficiency of the pipeline. There is also a risk of damage to the pipeline.

The inventor of the present application has further studied the above problems, and has completed an invention relating to a control technology capable of stably starting and stopping in a CO2-free power generation system.
The gist of the present invention is as follows. That is, the CO2 recovery power generation system according to the present invention is
(1) In a power generation system that supplies power generated by engine power and heat generated by exhaust heat recovery outside the system, hydrocarbon-based fuel supplied into the piston, pure oxygen, recirculated EGR gas or / and air, An engine configured to be combustible in a stratified state in the cylinder, an EGR system that recirculates part of the engine exhaust gas, and CO2 gas by cooling and removing H2O components in the exhaust gas other than the recirculation The CO2 recovery system boosted by the compressor, the EGR gas amount control means for adjusting the recirculation gas amount in the EGR system, the CO2 concentration in the exhaust gas in the CO2 recovery system A CO2 concentration detecting means for detecting the intake air, an intake three-way valve capable of switching the engine intake to the air intake side and / or the EGR gas intake side, and an exhaust gas flow path upstream of the compressor An exhaust three-way valve that can be switched to the compressor side and / or the atmosphere release side, and based on the CO2 concentration in the exhaust gas when the engine is started or stopped, the EGR gas amount control means, the intake air It is characterized in that stable start / stop and high-concentration CO2 gas recovery guarantee are possible by operating one or more of the three-way valve or the exhaust three-way valve.

As a means for “combustible in a stratified state”, for example, a swirl flow, a tumble flow, or a combination thereof can be suitably used.
The “CO2 concentration detection means” is not limited to the one that directly measures the CO2 concentration by the CO2 sensor, but instead of or in addition to this, the residual O2 concentration, the residual CO concentration, the residual H2 concentration, or the residual hydrocarbon (HC) The thing which detects CO2 density | concentration indirectly by measurement of density | concentration etc. is also included.
(2) In the above invention, the EGR gas amount control means is a flow rate adjusting valve disposed in the EGR system.
(3) In the invention of (1), the EGR gas amount control means is a variable valve timing mechanism that can adjust the valve timing of intake and exhaust.

In addition, the start-up operation control method of the CO2 recovery power generation system according to the present invention includes:
(4) In the inventions of the above (1) to (3), starting the engine in a state where the intake three-way valve is set to the air intake side and the exhaust three-way valve is set to the air release side flow path, Operating the EGR gas amount control means to increase the ratio of EGR gas supplied to the engine and operating the intake three-way valve to decrease the air intake amount from the air intake side stepwise; Increasing the supply amount of pure oxygen corresponding to the reduced amount of intake air, maintaining operation while maintaining the amount of oxygen necessary for combustion, and switching the intake three-way valve completely to the EGR gas intake side; When the fuel is burned with a mixture of EGR gas and pure oxygen, and when the engine combustion state is stabilized and the recovered CO2 concentration exceeds a predetermined threshold, the exhaust three-way valve is operated to The road is large From the open side to switch stepwise the compressor side, characterized in that it comprises the steps of: compressing the recovered CO2.

(5) In the inventions of the above (1) to (3), when the supply of fuel and oxygen is gradually reduced, and when the CO2 concentration falls below a predetermined threshold value, the exhaust three-way valve is operated to At the step of switching the gas flow path from the compressor side to the atmosphere release side, and at the stage where the supply of fuel and oxygen is stopped, the intake three-way valve is operated to switch the intake flow path to the air intake side, and coasting operation is performed. Replacing the inside of the engine and the compressor inside with air, air intake in the engine, exhaust from the atmosphere open side in the compressor, and inertial operation of the engine and the compressor CO2. And a step of stopping the operation after replacing the flow path with air.

According to the present invention, even when switching to air supply or mixing air in the system start / stop process, it is possible to avoid damage to the engine and the CO2 compressor due to deterioration of combustion, and stable start / stop There is an effect of securing.
Further, when the recovered CO2 is pumped to the processing pipeline and processed, it is possible to avoid a decrease in the CO2 concentration in the exhaust gas due to air mixing, so the compression efficiency when boosting the CO2 for pipeline injection There is an effect that it is possible to prevent a reduction in the processing efficiency of the pipeline and damage to the pipeline due to a decrease in the amount of impurities and the mixing of impure gas into the pipeline.
Furthermore, in the process of increasing the concentration of CO2 gas, a cogeneration system capable of cogeneration can be constructed by recovering the heat obtained by heat exchange.

It is a figure showing the whole CO2 collection type cogeneration (CG) system 1 composition (side cross section) concerning one embodiment of the present invention. It is a figure which shows a cross-sectional structure same as the above. FIG. 3 is a diagram showing a stratified combustion mode in a combustion chamber of the engine 2. It is a figure which shows the flow of the intake air and exhaust_gas | exhaustion in the initial stage at the time of starting. It is a figure which shows the flow of the intake and exhaust in the middle stage at the time of starting. It is a figure which shows the flow of the intake air and exhaust_gas | exhaustion at the time of steady operation. It is a figure which shows the operation control flow at the time of starting of CG system 1. It is a figure which shows the flow of the intake air and exhaust_gas | exhaustion in the initial stage at the time of a stop. It is a figure which shows the flow of the intake air and exhaust_gas | exhaustion in the stage just before a stop. It is a figure which shows the operation control flow at the time of a stop of CG system. 1 is a diagram illustrating a configuration of a conventional CO2 recovery cogeneration system 100. FIG.

Hereinafter, a CO2 recovery cogeneration system (hereinafter abbreviated as CG system) according to an embodiment of the present invention will be described in more detail with reference to FIGS. It is needless to say that the scope of the present invention is described in the claims and is not limited to the following embodiments.
<System configuration>
1 and 2, a CO2 recovery type CG system 1 according to this embodiment includes a drive system 3 that uses an engine 2 as a drive source, a fuel supply system 7 that supplies fuel and oxygen to the engine 2, An EGR system 5 that recirculates exhaust gas to the engine 2, a CO2 recovery system 6 that branches from the EGR system 5 and recovers CO2 in the exhaust gas, and combustion of the engine 2 during startup / stop and steady operation A combustion control system 8 that performs state monitoring and combustion control is provided as a main component.

The drive system 3 mainly includes an engine 2 that is a drive source, a generator 9 that is connected to the engine 2 via a crankshaft 2b, and a compressor 4 that is connected via a transmission gear 2c. The engine 2 is a four-cylinder four-cycle engine having four cylinders 2a. One end side of the crankshaft 2b is connected to the compressor side shaft 4a via a transmission gear 2c, and the other end side is a generator 9. Directly connected to These transmission devices are configured to transmit engine driving force to the generator 9 and the compressor 4.
The cylinder 2a, the intake / exhaust valve camshafts 2i and 2j, the piston camshaft 2f, and the compressor 4 of the engine 2 are stored together in the cylinder block 2e. A cavity (not shown) is provided in the piston head 2h of each cylinder, and a swirl control valve (not shown) is provided in the intake port 5g so as to promote swirl flow formation in the cylinder. It is configured.

  The compressor 4 is composed of two 2-cycle reciprocating compressors 4a and 4b. An intercooler 4c for cooling the exhaust CO2 gas is interposed between the flow paths of the compressors 4a and 4b. As described above, since the compressor 4 and the engine 2 are both reciprocating, they share the intake and exhaust valve camshafts 2i and 2j. That is, the intake and exhaust valve cams of the engine 2 and the valve cams of the compressor 4 have different cam profiles, but both cams are configured on a common camshaft so that they have independent camshafts. In comparison, the apparatus can be made compact and simple.

  The fuel supply system 7 includes a liquid fuel injector 7a at the end of a fuel supply line 7c that supplies hydrocarbon liquid fuel, and an oxygen injector 7b at the end of an oxygen supply line 7d that supplies pure oxygen as an oxidant. Each is prepared independently. This is because liquid fuel is used, so that it is possible to inject fuel to the optimum mixing point in the intake port 5g in consideration of difficulty in mixing with the oxidant (oxygen or air). In FIG. 1 (a), illustration is omitted except for one cylinder, but the other systems are configured in the same manner.

The EGR system 5 includes a turbocharger 5d including an EGR line 5a for recirculating engine exhaust gas collected in the exhaust manifold 5j to each cylinder, a turbine 5da in the EGR line 5a path, and a compressor 5db using this as a drive source. And a (second) heat exchanger (intercooler) 5c, which is interposed between the turbine 5da and the compressor 5db and cools the recirculated gas and condenses and removes moisture as a main component.
The EGR system 5 is further provided with an air intake line 5f for taking in air at the time of starting and stopping, and an intake three-way valve 5e that can switch intake to the EGR line side / air intake line side, as will be described later. ing.

The CO2 recovery system 6 branches from the EGR line 5a on the downstream side of the turbine 5da, and is interposed in the CO2 recovery line 6b for guiding the engine exhaust gas to the compressor 4 and the CO2 recovery line 6b, and exchanges heat with the exhaust gas. The first heat exchanger 6a for taking out the heat and the compressor 4 for increasing the pressure of the recovered CO2 gas to the pressure of the CO2 recovery pipeline 6c, and the pressure supply for pumping the CO2 gas after the pressure increase to the pipeline 6c And a main pipe 6f.
As will be described later, the CO2 recovery system 6 further includes an atmospheric open line 6e for releasing CO2 gas at the time of starting and stopping, and an exhaust three-way valve 6d capable of switching the exhaust to the compressor side / atmospheric open line side. Is provided.

The combustion control system 8 includes a flow rate control valve 7e interposed in the route of the oxygen supply line 7d, a flow rate adjustment valve 5b interposed in the route of the EGR line 5a, an intake three-way valve 5e, and an exhaust three-way valve 6d. A CO2 sensor S3 interposed in the CO2 recovery line 6b, an in-cylinder pressure sensor S1 and a temperature sensor S2 disposed in the cylinder 2a, and each regulating valve and three-way based on the detection values of each sensor. Combustion control device 8a that commands valve opening adjustment and performs system operation control during steady operation and startup / stop is provided as a main component.
Further, the combustion control device 8a is provided with a function (variable valve timing mechanism) for adjusting the injection timing and injection time of fuel or oxygen and adjusting the opening / closing timing of an intake / exhaust valve (not shown) of the engine. The combustion control device 8a can be implemented by a microcomputer equipped with a CPU, clock, RAM, ROM, bus, I / O interface, and the like.

<Combustion mode during steady operation>
The CG system 1 is configured as described above. Next, the behavior of fuel, oxygen, and EGR gas in the engine 2 during steady operation will be described with reference to FIG. During steady operation, the intake three-way valve 5e is set on the EGR line 5a side, and the exhaust three-way valve 6d is set on the compressor 4 side. In this state, oxygen is injected into the intake port 5g via the oxygen injector 7b and further flows into the center of the cylinder. On the other hand, the EGR gas returned to the intake manifold 5h via the EGR line 5a forms a vortex along the inner wall surface of the cylinder 2a via the intake port 5g. Thereby, oxygen for combustion is formed in the center of the cylinder, and gas stratified as EGR gas is formed in the outer peripheral portion, and the stratified state is maintained by forming a swirl flow in the cylinder. In this state, liquid fuel is directly injected into the center of the cylinder by the fuel injector 7d, and the injected fuel reacts with oxygen in the center of the cylinder, ignites and burns. In this case, the air-fuel mixture on the inner layer side burns, but since the EGR gas is present on the outer layer side, adhesion of unreacted fuel gas and residual oxygen to the inner wall surface of the cylinder 2a is prevented. Upon completion of combustion, the composition of the exhaust gas is only CO2 and H2O, and after being collected in the exhaust manifold 5j, is led to the EGR system 5 and the CO2 recovery system 6.

  Next, an aspect of exhaust gas recirculation in the EGR system 5 during steady operation will be described. The exhaust gas discharged from the exhaust manifold 5j is depressurized and reduced in temperature in the turbine 5da of the turbocharger 5d, and a part thereof is guided to the EGR line 5a. In addition, when the pressure in the turbine 5da is reduced and the temperature is lowered, a part of the moisture in the exhaust gas is condensed and recovered as drain water. Subsequently, the exhaust gas is cooled by the intercooler 5c, and further, water is removed, and the EGR gas mainly containing CO2 is boosted again in the compressor 5db, and is returned to the intake manifold 5h inlet via the EGR line 5a.

  Next, an aspect of CO2 gas recovery in the CO2 recovery system 6 will be described. The exhaust gas branched from the EGR system 5 is cooled and removed by the heat exchanger 6a to become high-concentration CO2 gas, while the heat recovered here is used outside the system as hot water or the like. The CO2 gas discharged from the heat exchanger 6a is guided to the compressor 4 and stepped up to the required pressure for press-fitting into the CO2 recovery pipeline 6c in stages. In the pressurization process, the CO2 gas is cooled by the intercooler 4c, and the collected heat is used outside the system. The pressurized CO2 gas is sent to the recovery pipeline 6c. With the above flow, CO2 recovery is realized without the engine exhaust gas being diffused into the atmosphere.

<Operation control at startup>
Next, with reference to FIGS. 3 and 4, a mode of operation control at the start of the CG system 1 will be described.
Referring to FIG. 3A, before starting, the flow rate adjustment valve 5b is closed, the intake three-way valve 5e is set to the flow path on the air intake line 5f side, and the exhaust three-way valve 6d is set to the flow path on the atmosphere release line 6e side. (S101). In this state, when there is an operation command from the operation manager (Y in S102), air is taken in through the air intake line 5f, fuel is combusted by oxygen in the air, and the engine 2 is started (S103). The exhaust gas is exhausted through the atmosphere open line 6e.
After the engine is started, it is determined whether or not combustion has reached a stable state by the in-cylinder pressure sensor S1 and the temperature sensor S2 in the cylinder (S104), and if the unstable state continues, the fuel injection amount, the fuel injection timing Then, combustion improvement control such as adjustment of the compression ratio is performed (S105).

Referring to FIG. 3 (b), when the combustion reaches a stable combustion state from a transient state (Y in S104), the operation mode is switched (S106). That is, by gradually switching the flow rate adjusting valve 5b to the EGR line 5a side, the air intake amount from the air intake line 5f side is decreased while increasing the EGR gas ratio (S106). The oxygen corresponding to the decrease is compensated by the increase in the amount of oxygen intake from the oxygen injector 7b.
By the above operation control, the air intake line 5f is finally closed, and the air supply amount mainly corresponding to the nitrogen (N2) portion of the air reduction amount accompanying the closure is compensated by the recirculation CO2 from the EGR line. The flow rate corresponding to the oxygen (O2) component is compensated by adjusting the flow rate via the oxygen injector 7b, so that the fuel is burned with the mixture of the circulating exhaust gas and pure oxygen.
During steady operation, the engine combustion state is determined based on the measured values of the in-cylinder pressure S1, the temperature sensor S2, and the CO2 sensor S3 (S107). Specifically, the presence or absence of pressure abnormality, knocking occurrence, and in-cylinder temperature abnormality is monitored to determine whether or not the combustion speed is appropriate.

When it is determined in S107 that the combustion speed is excessive, the combustion slowing control is appropriately executed (S108). In particular,
(A) Delay ignition and fuel injection timing.
(B) The fuel or oxygen injection amount is reduced.
(C) Lower the compression ratio.
(D) By adjusting the injection timing and injection time of fuel or oxygen and operating the variable valve timing mechanism, the stratification degree of the stratified gas mixture is lowered and uniform with the EGR gas.
(E) The EGR heat exchange amount is increased to lower the EGR gas temperature.

Further, when it is determined in S107 that the combustion rate is slow, and when the CO2 concentration is lower than a predetermined threshold value in S110 (N in S110), the following combustion promotion control (S106) is appropriately executed (S109). ). Specifically, the following operations are performed singly or in combination.
(A) Advance ignition and fuel injection timing.
(B) Increase the fuel or oxygen injection amount.
(C) Increase the compression ratio.
(D) The degree of stratification of the stratified mixture is increased by adjusting the injection timing and injection time of fuel or oxygen and operating the variable valve timing mechanism.
(E) Decreasing the amount of EGR heat exchange and increasing the EGR gas temperature.

  Referring to FIG. 3 (c), when the operating state is stabilized by the control of S107-S110 and the recovered CO2 concentration exceeds a predetermined level, the exhaust three-way valve 6d is gradually operated to turn on the CO2 compressor side 6b. The flow path is switched, the CO2 is compressed by the compressor 4, and the recovered CO2 is sent to the CO2 processing pipeline 6c via the pressure feed pipe 6f (S111).

<Operation control at stop>
Next, with reference to FIG. 5 and FIG. 6, the operation control flow at the time of stop of the CG system 1 will be described.
In the steady operation mode (see FIG. 3 (c) above), the flow rate adjustment valve 5b is fully open, the intake three-way valve 5e is set on the EGR line 5a side, and the exhaust three-way valve 6d is set on the compressor 4 side flow path. (S201). When there is an operation stop command from the operation manager (Y in S202), the steady operation mode is switched to the stop operation mode (S203). Specifically, the flow rate adjustment valve 5b is closed stepwise, and the intake three-way valve 5e is changed stepwise to the air intake line 5f side. At the same time, the amount of oxygen supplied from the oxygen injector 7b is decreased stepwise (see FIG. 5A).

During the operation mode switching, the CO2 concentration is measured by the CO2 sensor S3, and it is determined whether or not the CO2 concentration is maintained at a predetermined threshold value or more (S204). If the CO2 concentration is below the threshold value (N in S204), the exhaust three-way valve 6d is switched to the atmosphere open line 6e side (S205) (see FIG. 5B). Thereby, it is possible to prevent the exhaust gas whose CO2 concentration is lowered due to air mixing from flowing into the CO2 pipeline 6c.
When the predetermined CO2 concentration is maintained (Y in S204), the combustion stabilization control similar to S107-S109 at the start-up is performed in order to secure stable combustion at the time of shifting to the operation mode (S206-). S208).

After the operation mode switching is completed (Y in S209), the engine stop operation is started. Specifically, the following steps are performed.
(A) After the stop determination, the supply of fuel and oxygen is gradually reduced (S210).
(B) While stopping the supply of fuel and oxygen, the intake three-way valve 5e is switched from the EGR line 5a side to the air intake line side 5f side, and the cylinder 2a and the compressor 4 are replaced by air (S211).
(C) Disconnect the drive shaft of the engine 2 and the shaft of the generator. Thereby, even after the fuel and oxygen supply stop, the engine 2 and the compressor 4 can continue to rotate with inertia for a while (S212).
(D) The entire system is air purged by air intake to the engine 2, exhaust from the air release line 6 e of the compressor 4, and inertial operation of the engine 2 and the compressor 4 (S 213). (S214).

In the present embodiment, the fuel supply system has been described with an example in which a liquid fuel injector and an oxygen injector are provided independently.
(1) Premixed gas injection + spark ignition (or liquid fuel micro injection ignition)
(2) Pure oxygen injection + liquid fuel spray ignition (3) (gas or liquid) fuel injection + pure oxygen injection + spark ignition (or liquid fuel micro injection ignition)
Other fuel and oxygen supply modes can also be employed.

Moreover, although the example which forms a swirl flow in an engine cylinder and carries out stratified combustion was shown, it can also be set as the form which carries out stratified combustion by forming a tumble flow instead.
Moreover, although the example which uses a reciprocating compressor as a CO2 compressor was shown, it can also be set as the form which replaces this and uses a single stage or a multistage axial flow, or a scroll type compressor.
Moreover, although the example which uses a CO2 sensor as a CO2 density | concentration detection means of a CO2 collection line was shown instead of or in addition to this, an O2 sensor, a CO sensor, an H2 sensor, or a hydrocarbon (HC) sensor, etc. It is also possible to indirectly detect the CO2 concentration by using.
In addition, an example in which transient combustion stabilization control at start / stop is performed by controlling the exhaust gas recirculation amount by adjusting the opening of the flow rate adjustment valve 5b according to the combustion state of the engine or the recovered CO2 concentration. However, instead of this, the combustion control may be performed by adjusting the opening and closing timing of the intake and exhaust valves by a variable valve timing mechanism.

  The present invention is widely applicable not only as a CO2 recovery type cogeneration system but also as a CO2 free system for recovering CO2 in engine exhaust gas.

DESCRIPTION OF SYMBOLS 1 ... CO2 collection type cogeneration (CG) system 2 ... engine 2a ... cylinder 2i ... intake valve camshaft 2j ... exhaust valve camshaft 3 ... drive system 4 .... Compressor 5 ... EGR system 4c, 5c ... intercooler (heat exchanger)
5d ... turbocharger 5e ... intake three-way valve 5f ... air intake line 6 ... CO2 recovery system 6a ... heat exchanger 6c ... CO2 recovery pipeline 6d ... exhaust three-way Valve 6e ... Open air line 7 ... Fuel supply system 7a ... Liquid fuel injector 7b ... Oxygen injector 8 ... Combustion control system 9 ... Generator S1 ... In-cylinder pressure Sensor S2 ... Temperature sensor S3 ... CO2 sensor

Claims (5)

In a power generation system that supplies power generated by engine power outside the system,
An engine configured to burn a mixture of hydrocarbon-based fuel, pure oxygen, and recirculated EGR gas or / and air supplied into the piston in a stratified state in the cylinder;
An EGR system that recirculates part of the engine exhaust gas;
A CO2 recovery system in which the H2O component in the exhaust gas other than recirculation is cooled and removed to increase the concentration of CO2 gas, and then the pressure is increased by a compressor;
EGR gas amount control means for adjusting the amount of recirculated gas in the EGR system;
CO2 concentration detection means for detecting the CO2 concentration in the exhaust gas in the CO2 recovery system;
An intake three-way valve that allows switching between engine intake and air intake and / or EGR gas intake;
An exhaust three-way valve that enables the exhaust gas flow path to be switched to the compressor side and / or the atmosphere open side on the upstream side of the compressor,
When the engine is started or stopped, stable start / stop and high operation can be performed by operating one or more of the EGR gas amount control means, the intake three-way valve, and the exhaust three-way valve based on the CO2 concentration in the exhaust gas. A CO2 recovery type power generation system characterized in that concentration CO2 gas recovery guarantee is possible.   The CO2 recovery type power generation system according to claim 1, wherein the EGR gas amount control means is a flow rate adjusting valve disposed in the EGR system.   2. The CO2 recovery type power generation system according to claim 1, wherein the EGR gas amount control means is a variable valve timing mechanism capable of adjusting intake / exhaust valve timing. A start-up operation control method for the CO2 recovery power generation system according to claim 1,
Starting the engine with the intake three-way valve set to an air intake side and the exhaust three-way valve set to a flow path on the atmosphere open side;
Operating the EGR gas amount control means to increase the EGR gas ratio supplied to the engine and operating the intake three-way valve to decrease the air intake amount from the air intake side stepwise;
Increasing the supply amount of pure oxygen corresponding to the decrease in the air intake amount, and continuing the operation while maintaining the oxygen amount necessary for combustion;
Switching the intake three-way valve completely to the EGR gas intake side, and burning fuel with a mixture of EGR gas and pure oxygen;
When the engine combustion state is stable and the recovered CO2 concentration exceeds a predetermined threshold, the exhaust three-way valve is operated to switch the exhaust gas flow path gradually from the open side to the compressor side. Compressing the recovered CO2;
A start-up operation control method for a CO2 recovery type power generation system, comprising: A CO2 recovery type power generation system stop operation control method according to claims 1 to 3,
Gradually reducing the supply of fuel and oxygen;
Switching the exhaust gas flow path from the compressor side to the atmosphere opening side by operating the exhaust three-way valve when the CO2 concentration becomes a predetermined threshold value or less;
When the supply of fuel and oxygen is stopped, operating the intake three-way valve to switch the intake passage to the air intake side, and replacing the inside of the engine and the inside of the compressor that are operating in inertia with air; ,
Air intake in the engine, exhaust from the atmosphere open side in the compressor, and the step of stopping the operation after replacing all the flow paths with air by inertial operation of the engine and the compressor CO2,
A stop operation control method for a CO2 recovery power generation system.

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