JP7196730B2 - Hydrocarbon production device and hydrocarbon production method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hydrocarbon production device and a hydrocarbon production method.

Conventionally, there has been known a hydrocarbon compound production apparatus that recovers carbon dioxide from exhaust gas emitted from a combustion furnace or the like and reacts it with hydrogen to produce a hydrocarbon compound such as methane. For example, Patent Literature 1 discloses a technique for producing methane from carbon dioxide in exhaust gas and hydrogen supplied from a water electrolysis device.

WO2016/076041

2. Description of the Related Art Conventionally, there has been known a storage part that temporarily stores a mixed gas of carbon dioxide and hydrogen to be supplied to a reaction part in order to stably produce methane. The reservoir can be reduced in size by pressurizing the gas mixture using boost power. However, there is a problem that system efficiency decreases when boosting power increases.

The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide a technique for reducing the size of a hydrocarbon production apparatus while suppressing a decrease in system efficiency.

The present invention has been made to solve at least part of the above problems, and can be implemented as the following modes.

(1) According to one aspect of the present invention, a hydrocarbon production apparatus is provided. This hydrocarbon production apparatus includes a main reaction section for producing a hydrocarbon compound using carbon dioxide and hydrogen, a supply channel through which a mixed gas containing carbon dioxide and hydrogen to be supplied to the main reaction section flows, a storage section provided on the supply channel for storing the mixed gas before being supplied to the main reaction section; and a storage section provided on the upstream side of the storage section in the supply channel for storing and a pre-reaction section that generates a hydrocarbon compound using the mixed gas before being processed, and the storage section stores the mixed gas containing the hydrocarbon compound generated in the pre-reaction section. be.

According to this configuration, the storage section stores the mixed gas containing the hydrocarbon compound produced in the pre-reaction section and the unreacted carbon dioxide and hydrogen in the pre-reaction section. When a hydrocarbon compound is produced from a mixed gas of carbon dioxide and hydrogen, the volume of the mixed gas containing the hydrocarbon compound after the reaction is smaller than the volume of the mixed gas without the hydrocarbon compound before the reaction. From this, when a hydrocarbon compound is produced in the pre-reaction part using the mixed gas before being stored in the storage part, the volume of the mixed gas stored in the storage part is smaller than when the pre-reaction part is not provided. Become. This makes it possible to reduce the size of the reservoir. Moreover, since the volume of the mixed gas stored in the storage section is small, the power required for pressurization can be reduced. Therefore, it is possible to reduce the physical size of the apparatus while suppressing a decrease in system efficiency.

(2) In the hydrocarbon production apparatus of the above aspect, the supply channel is provided between the pre-reaction section and the storage section, and the fuel is taken out from the pre-reaction section and before being stored in the storage section. A separation section may be provided for separating high boiling point components contained in the mixed gas from the mixed gas. According to this configuration, high-boiling-point components generated by the hydrocarbon compound generation reaction in the pre-reaction section, such as moisture generated when methane is generated, are separated from the mixed gas before being stored in the storage section. As a result, the volume of the mixed gas stored in the storage section can be further reduced, so that the storage section can be further reduced in size. Therefore, the physical size of the device can be further reduced.

(3) In the hydrocarbon production apparatus of the above aspect, a downstream side of the supply flow path is provided between the pre-reaction section and the storage section and pressurizes the mixed gas before being stored in the storage section. A side booster may be provided. According to this configuration, the mixed gas stored in the storage section can be compressed before being stored in the storage section, so the volume of the mixed gas stored in the storage section can be further reduced. Therefore, the size of the device can be further reduced because the reservoir can be made smaller.

(4) In the hydrocarbon production apparatus of the aspect described above, a first concentration information acquisition section provided between the pre-reaction section and the storage section for acquiring information related to the concentration of the mixed gas; a downstream pressure control unit that adjusts the pressure of the mixed gas stored in the storage unit by controlling the downstream pressure increasing unit using the information acquired by the concentration information acquisition unit. . According to this configuration, for example, the downstream pressure control section estimates the reaction rate of the hydrocarbon compound in the pre-reaction section using information related to the concentration of the mixed gas. When the estimated reaction rate of the hydrocarbon compound in the pre-reaction section is lower than the target reaction rate, the downstream pressure control section adjusts the mixed gas before being stored in the storage section according to the difference between the estimated reaction rate and the target reaction rate. control the lower booster so that it is compressed Thereby, the storage portion having a size preset according to the target reaction rate can store the mixed gas supplied to the main reaction portion. Further, the downstream pressure control section uses the estimated reaction rate of the hydrocarbon compound in the pre-reaction section to adjust the pressure of the mixed gas supplied from the storage section to the main reaction section within the range of variation expected in the main reaction section. The pressure of the mixed gas can be modified so that

(5) In the hydrocarbon production apparatus of the above aspect, an upstream pressurizing section is provided upstream of the pre-reaction section in the supply flow path and pressurizes the mixed gas supplied to the pre-reaction section. good too. According to this configuration, the pressure of the mixed gas supplied to the pre-reaction section can be increased, so that the reaction rate of the hydrocarbon compound in the pre-reaction section can be improved. As a result, the volume of the mixed gas stored in the storage section can be further reduced, so that the storage section can be further reduced in size. Therefore, the physical size of the device can be further reduced.

(6) In the hydrocarbon production apparatus of the aspect described above, a second concentration information acquisition section provided between the pre-reaction section and the storage section for acquiring information related to the concentration of the mixed gas; an upstream pressure control unit that adjusts the pressure of the mixed gas supplied to the pre-reaction unit by controlling the upstream pressure increasing unit using the information acquired by the concentration information acquisition unit. good. According to this configuration, for example, the upstream pressure control section estimates the reaction rate of the hydrocarbon compound in the pre-reaction section using information related to the concentration of the mixed gas. The upstream pressure control section controls the upstream pressure increasing section to further compress the mixed gas supplied to the pre-reaction section when the estimated reaction rate of the hydrocarbon compound in the pre-reaction section is lower than the target reaction rate. Thereby, the reaction rate in the pre-reaction section can be improved and the reaction rate can be set to the target reaction rate. Therefore, a reservoir having a size preset according to the target reaction rate can store the mixed gas supplied to the main reaction section.

(7) In the hydrocarbon production apparatus of the above aspect, the pre-reaction section is formed with a heat medium flow path through which a heat medium for recovering reaction heat of the formation of the hydrocarbon compound in the pre-reaction section flows. The hydrocarbon production apparatus further includes a gas information acquisition unit that acquires information related to the concentration or flow rate of the mixed gas supplied to the pre-reaction unit, and adjusts the flow rate of the heat medium flowing through the heat medium flow path. A flow rate adjusting section and a flow rate controlling section that controls the flow rate adjusting section using the information acquired by the gas information acquiring section may be provided. According to this configuration, the temperature of the pre-reaction section is adjusted so that the reaction rate in the pre-reaction section becomes a desired reaction rate using information related to the concentration or flow rate of the mixed gas supplied to the pre-reaction section. Adjust with the flow rate of the heat transfer medium. Accordingly, by adjusting the temperature of the pre-reaction section with the flow rate of the heat medium, the reaction rate in the pre-reaction section can be increased, and the volume of the mixed gas stored in the storage section can be further reduced. Therefore, the physical size of the device can be further reduced.

The present invention can be implemented in various aspects, for example, a control method for a hydrocarbon production apparatus, a computer program for causing a computer to execute this control method, a hydrocarbon production method, and a hydrocarbon production apparatus manufacturing method. It can be realized in the form of a method, a carbon dioxide recovery device, a carbon dioxide circulation system, a fuel production device using hydrocarbon as fuel, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which showed schematic structure of the hydrocarbon production apparatus of 1st Embodiment. FIG. 4 is an explanatory diagram showing temporal changes in flow rate and concentration of a mixed gas at an outlet of an adsorption section; FIG. 3 is an explanatory diagram for explaining the rate of volume reduction due to a methanation reaction; FIG. 5 is an explanatory diagram showing the relationship between the gas concentration of the reaction part and the volume of the storage part in a comparative example; FIG. 4 is an explanatory diagram showing the relationship between the gas concentration of the reaction part and the volume of the storage part in the first embodiment; FIG. 4 is an explanatory diagram showing the relationship between the gas concentration of the reaction part and the volume of the storage part in the first embodiment; It is an explanatory view showing a schematic configuration of a hydrocarbon production apparatus of a second embodiment. It is an explanatory view showing a schematic configuration of a hydrocarbon production apparatus of a third embodiment. FIG. 5 is an explanatory diagram showing the relationship between the concentration of gas supplied to the pre-reaction section and the flow rate of the heat medium;

<First embodiment>
FIG. 1 is an explanatory diagram showing a schematic configuration of a methane production apparatus 1 according to the first embodiment. The methane production apparatus 1 is an apparatus for producing methane (CH ₄ ) from carbon dioxide (CO ₂ ) and hydrogen (H ₂ ). In this embodiment, CO ₂ recovered from exhaust gas is used to produce CH ₄ . . The methane production apparatus 1 includes a first adsorption section 11, a second adsorption section 12, a hydrogen supply source 13, a supply channel 15, a pre-reaction section 20, a condenser 25, a booster 30, and a storage section. 35 , a main reaction section 40 , a first CO ₂ concentration meter 46 , a second CO ₂ concentration meter 47 and a control section 50 . Note that this embodiment can also be applied to a hydrocarbon production apparatus that produces hydrocarbon compounds other than _CH4 . For example, compounds composed of carbon and hydrogen, such as ethane and propane, and It can also be applied to a "hydrocarbon production apparatus" for producing a compound composed of and as a "hydrocarbon compound".

The first adsorption unit 11 and the second adsorption unit 12 recover CO ₂ contained in the exhaust gas from the exhaust gas. The first adsorption part 11 and the second adsorption part 12 contain therein adsorbents 11a and 12a such as materials having CO ₂ storage performance, such as zeolite, activated carbon, and silica gel. The first adsorption part 11 and the second adsorption part 12 are connected to an exhaust gas supply source 5, for example a combustion furnace or a blast furnace, which discharges exhaust gas containing _CO2 . The exhaust gas discharged from the exhaust gas supply source 5 flows into the first adsorption unit 11 and the second adsorption unit 12 through the dehydration unit 6 that separates moisture from the exhaust gas.

The exhaust gas alternately flows into the first adsorption unit 11 and the second adsorption unit 12, thereby recovering CO ₂ from the exhaust gas. Specifically, when exhaust gas flows into the first adsorption unit 11 and CO ₂ is separated from the exhaust gas by adsorption of the adsorbent 11 a, H ₂ is supplied to the second adsorption unit 12 from the hydrogen supply source 13 described later. inflow. In the second adsorption part 12, the inflow of H ₂ desorbs CO ₂ already adsorbed on the adsorbent 12a from the adsorbent 12a. CO ₂ desorbed from adsorbent 12a is mixed with H ₂ . Further, when exhaust gas flows into the second adsorption unit 12 and CO ₂ is separated from the exhaust gas by adsorption of the adsorbent 12 a, H ₂ supplied from the hydrogen supply source 13 flows into the first adsorption unit 11 . In the first adsorption part 11, CO ₂ desorbed from the adsorbent 12a and H ₂ are mixed by the inflow of H ₂ . In this manner, the first adsorption unit 11 and the second adsorption unit 12 alternately repeat adsorption and desorption, thereby recovering CO ₂ from the exhaust gas and producing a mixed gas of CO ₂ and H ₂ . Generate.

The hydrogen supply source 13 is configured by, for example, a water electrolysis device or a hydrogen tank. The hydrogen supply source 13 is connected to the first adsorption section 11 and the second adsorption section 12 via the hydrogen flow path 13a. The H ₂ supplied through the hydrogen flow path 13 a purges the insides of the first adsorption section 11 and the second adsorption section 12 and constitutes the mixed gas supplied to the pre-reaction section 20 with CO ₂ . The hydrogen supply source 13 is connected to the supply channel 15 between the later-described storage section 35 and the main reaction section 40 via the hydrogen channel 13b. A booster 13c for boosting the pressure of H ₂ supplied from the hydrogen supply source 13 to the supply channel 15 is arranged in the hydrogen channel 13b. The H ₂ supplied through the hydrogen flow path 13b joins the mixed gas just before being supplied to the main reaction section 40 and is used for the methanation reaction in the main reaction section 40 .

The supply flow path 15 is a flow path that connects the first adsorption section 11 and the second adsorption section 12 and the main reaction section 40, and the CO ₂ mixed in the first adsorption section 11 and the second adsorption section 12 and A mixed gas containing H ₂ is supplied to the main reaction section 40 . In this embodiment, a pre-reaction section 20, a condenser 25, a booster 30, and a storage section 35 are provided in this order on the supply channel 15. As shown in FIG.

The pre-reaction part 20 is a substantially cylindrical container for generating CH ₄ by a methanation reaction inside, and is composed of a double tube. A catalyst 21 containing a metal having methanation catalytic performance is arranged in the inner tube of the pre-reaction section 20 . Examples of metals having methanation catalytic performance include Ru and Ni. A heat medium channel 22 through which a heat medium capable of recovering heat generated by the methanation reaction flows is formed in the tube outside the pre-reaction section 20 .

A first adsorption section 11 and a second adsorption section 12 are provided on the upstream side of the pre-reaction section 20, and a condenser 25 is provided on the downstream side thereof. When a mixed gas containing CO ₂ and H ₂ is supplied to the pre-reaction section 20, a methanation reaction proceeds in part of the mixed gas to generate CH ₄ . A mixed gas containing the produced CH ₄ , H ₂ O as a “high boiling point component”, and unreacted CO ₂ and H ₂ is supplied to the condenser 25 through the supply passage 15 .

The condenser 25 is a heat exchanger capable of cooling a fluid, and cools the mixed gas containing CH ₄ and H ₂ O produced in the pre-reaction section 20 and unreacted CO ₂ and H ₂ . By cooling in the condenser 25, the H ₂ O contained in the mixed gas is condensed into water and separated from the mixed gas. The mixed gas from which water has been separated is supplied to the booster 30 through the supply flow path 15 .

The booster 30 is a pump capable of pressurizing the fluid, and boosts the pressure of the mixed gas from which water has been separated in the condenser 25 . In this embodiment, the degree of boosting by the booster 30 is set by the control unit 50, which will be described later. The mixed gas pressurized by the booster 30 is supplied to the storage section 35 through the supply flow path 15 .

The storage unit 35 is a tank that stores fluid, and stores the mixed gas pressurized by the booster 30 . The mixed gas stored in the storage section 35 joins with H ₂ supplied from the hydrogen supply source 13 in the supply channel 15 and is supplied to the main reaction section 40 .

The main reaction section 40 is a container having the same shape as the pre-reaction section 20, and a catalyst 41 is arranged in the inner tube. Catalyst 41, like catalyst 21, contains a metal having methanation catalytic properties. A heat medium channel 42 through which a heat medium capable of recovering heat generated by the methanation reaction flows is formed in the tube outside the main reaction section 40 .

Mixed gas containing CH ₄ temporarily stored in the storage section 35 and CO ₂ and H ₂ that have not reacted in the pre-reaction section 20 is supplied to the main reaction section 40 from the supply passage 15 . Inside the main reaction section 40, CH ₄ is produced by a methanation reaction using unreacted CO ₂ and H ₂ . The generated gas containing CH ₄ and H ₂ O generated in the main reaction section 40 is supplied to a device outside the methane production apparatus 1 via the generated gas flow path 16 connected to the downstream side of the main reaction section 40. be done.

A first CO ₂ concentration meter 46 detects the CO ₂ concentration of the mixed gas flowing through the supply flow path 15 between the condenser 25 and the booster 30 . The first CO ₂ concentration meter 46 outputs the detected CO ₂ concentration of the mixed gas to the controller 50 .

The second CO ₂ concentration meter 47 is a mixed gas flowing through the supply channel 15 between the storage section 35 and the main reaction section 40, and the CO of the mixed gas before the H ₂ supplied from the hydrogen supply source 13 joins. ₂ to detect concentrations. The second CO ₂ concentration meter 47 outputs the detected CO ₂ concentration of the mixed gas to the controller 50 .

The control unit 50 is a computer including a ROM, a RAM, and a CPU. It controls the entire device 1 . The control unit 50 has a pressure control unit 50a, a flow control unit 50b, and the like.

The pressure controller 50 a is electrically connected to the first CO ₂ concentration meter 46 and the booster 30 . The pressure control section 50a estimates the reaction rate of CH ₄ in the pre-reaction section 20 using the CO ₂ concentration of the mixed gas detected by the first CO ₂ concentration meter 46 . The pressure control unit 50 a controls the pressure booster 30 using the estimated reaction rate of CH ₄ to adjust the pressure of the mixed gas supplied to the storage unit 35 .

The flow controller 50b is electrically connected to the second CO ₂ concentration meter 47, the flow regulator 48 arranged in the supply channel 15, and the flow regulator 13d arranged in the hydrogen channel 13b. there is The flow rate regulator 48 detects the flow rate of the mixed gas flowing through the supply channel 15 between the storage section 35 and the main reaction section 40 and before the H ₂ supplied from the hydrogen supply source 13 joins. do. The flow control unit 50b uses the CO _{2 concentration of the mixed gas detected by the second CO 2 concentration} meter 47 and the flow rate of the mixed gas detected by the flow regulator 48 to adjust the mixed gas supplied to the main reaction unit 40. _Estimate the amount of H2 required. Flow control unit 50b controls flow regulator 13d so that the estimated amount of H ₂ is added to the mixed gas supplied from storage unit 35 to main reaction unit 40, so that the hydrogen supply source 13 supplies H 2 . Adjust the flow rate of ₂ .

In the present embodiment, when producing CH ₄ , as described above, the two adsorption units, ie, the first adsorption unit 11 and the second adsorption unit 12 are switched to recover CO ₂ from the exhaust gas. In the recovery of CO ₂ using these two adsorption units, when the adsorption step of adsorbing CO ₂ is performed in either one of the first adsorption unit 11 and the second adsorption unit 12, the first adsorption unit In the other adsorption section, either the section 11 or the second adsorption section 12, a desorption process is performed to desorb CO ₂ adsorbed on the adsorbent.

FIG. 2 is an explanatory diagram showing temporal changes in the flow rate and concentration of the mixed gas at the outlet of the adsorption section in the delithization step. FIG. 2 shows an example of temporal changes in flow rate and H ₂ /CO ₂ concentration at the adsorption section outlet (point P1 in FIG. 1) in the desorption step. In addition, in the desorption step in FIG. 2, the flow rate of H ₂ supplied to each of the first adsorption section 11 and the second adsorption section 12 is constant. In FIG. 2, the switching timing between the first adsorption unit 11 and the second adsorption unit 12 for the exhaust gas is indicated by time t0.

As shown in FIG. 2, immediately after switching the adsorption part, CO ₂ adsorbed by the adsorbent can be easily discharged, so the flow rate increases while the H ₂ /CO ₂ concentration decreases (see FIG. 2 after time t0). After that, as the desorption of CO ₂ in the adsorbent progresses, the adsorption amount decreases, and the amount of desorbed CO ₂ also decreases, so the H ₂ /CO ₂ concentration increases (after time t1 in FIG. 2). . After the H ₂ /CO ₂ concentration rises, the discharge of CO ₂ is accelerated by reducing the pressure in the adsorption section with a decompression pump (not shown) or heating the adsorbent with a heater during the desorption process, and the H ₂ /CO ₂ rises again. The concentration decreases (after time t2 in FIG. 2). However, as time elapses, the H ₂ /CO ₂ concentration rises again, so the adsorption section is switched and the desorption process is carried out in another adsorption section.

Thus, when CH ₄ is produced using CO ₂ recovered by the adsorbent, fluctuations in the supply amount and flow rate of CO ₂ are relatively large. Therefore, in the present embodiment, by temporarily storing the mixed gas of CO ₂ and H ₂ mixed in the first adsorption section 11 and the second adsorption section 12 in the storage section 35, suppress the fluctuation of the reaction rate of

Furthermore, in the present embodiment, the mixed gas of CO ₂ and H ₂ before being stored in the storage unit 35 is used to generate CH ₄ in the pre-reaction unit 20 provided on the upstream side of the storage unit 35, Moisture generated by the methanation reaction in the pre-reaction section 20 is separated from the mixed gas by the condenser 25 and recovered. This reduces the volume of the mixed gas stored in the storage section 35 .

FIG. 3 is an explanatory diagram for explaining the volume reduction rate due to the methanation reaction. FIG. 3(a) shows the material balance in the methane production apparatus 4, which is composed of the reaction section 10a shown in FIG. 3(b) and the condenser 10b that separates moisture from the produced gas discharged from the reaction section 10a. there is The reaction section 10a in FIG. 3(b) can be regarded as the pre-reaction section 20 in this embodiment, and the condenser 10b can be regarded as the condenser 25 in this embodiment.

FIG. 3(a) shows the ratio between the volume Vi of the mixed gas flowing into the methane production apparatus 4 and the volume Vo of the produced gas flowing out, with respect to the H ₂ /CO ₂ concentration shown on the horizontal axis. _FIG . 3(a) shows the relationship between the volume ratio Vo/Vi and the H2/ _CO2 concentration for _each of a plurality of CH4 reaction rates _{( CO2} conversion rate to CH4). As shown in FIG. 3(b), the volume Vo of the generated gas indicates a value obtained by removing moisture from the gas discharged from the reaction section 10a by the condenser 10b.

The reaction formula of the methanation reaction between carbon dioxide and hydrogen is the following formula (1).
_CO2 + _4H2- >CH4 _{+ 2H2O} (1)
As shown in equation (1), when 1 mol of _CO2 and ₄ mol of H2 react, 1 mol of CH4 and ₂ mol of _H2O are produced. In the methane production apparatus 4, 2 mol of H ₂ O is separated by the condenser 10b, so the gas corresponding to the volume Vi is 1 mol of CH ₄ . Therefore, in the methane production apparatus 4, when 5 mol of mixed gas is input, 1 mol of gas is discharged at the lowest value.

As shown in FIG. 3(a), the methanation reaction progresses so that the volume ratio Vo/Vi becomes a value smaller than 1 even if the reaction rate is about 10%. For example, when the H ₂ /CO ₂ concentration is 4 and the reaction rate is 100%, the volume ratio Vo/Vi is the minimum 0.2. Thus, in the methane production apparatus, the methanation reaction reduces the gas volume.

FIG. 4 is an explanatory diagram illustrating the relationship between the H ₂ /CO ₂ concentration at the inlet of the reaction section and the volume of the storage section in the methane production apparatus of the comparative example. In the methane production apparatus of the comparative example, the supply channel for supplying the mixed gas containing CO ₂ and H ₂ to the reaction section is provided with a storage section for temporarily storing the mixed gas, but the storage section of the present embodiment is provided. There is no device for producing CH ₄ from the mixed gas before storage, such as a pre-reactor. As shown in FIG. 4, it can be seen that the larger the volume of the reservoir, the more moderate the fluctuation of the H ₂ /CO ₂ concentration at the inlet of the reaction section. As the maximum pressure in the storage section is increased, the volume of the storage section can be reduced, but a larger boosting power is required, leading to a decrease in system efficiency.

FIG. 5 is an explanatory diagram illustrating the relationship between the H ₂ /CO ₂ concentration at the inlet of the main reaction section 40 (point P2 in FIG. 1) and the volume of the storage section 35 in the methane production apparatus 1 . FIG. 5 shows the time change of the H ₂ /CO ₂ concentration when the reaction rate in the pre-reaction section 20 is 40%. The value of the "storage unit volume" shown in FIG. 5 indicates the ratio to the volume of the storage unit provided in the methane production apparatus of the comparative example shown in FIG. As shown in FIG. 5, even if the volume of the reservoir is 0.67 times or 0.83 times that of the comparative example, the H ₂ /CO ₂ concentration at the inlet of the main reaction part 40 changes as follows: It can be seen that the reservoir volume of the comparative example is relaxed to the same extent as 1.0.

FIG. 6 is an explanatory diagram illustrating the relationship between the H ₂ /CO ₂ concentration at the inlet of the main reaction section 40 and the volume of the storage section 35 in the methane production apparatus 1 . FIG. 6 shows the time change of the H ₂ /CO ₂ concentration when the reaction rate in the pre-reaction section 20 is 70%. As shown in FIG. 6, even if the volume of the storage section is 0.5 times that of the storage section of the comparative example, the fluctuation of the H ₂ /CO ₂ concentration at the inlet of the main reaction section 40 is the same as that of the storage section of the comparative example. It can be seen that the volume is relaxed to the same extent as 1.0.

Further, in the methane production apparatus 1 of the present embodiment, the pressure control unit 50a uses the CO ₂ concentration of the mixed gas detected by the first CO ₂ concentration meter 46 to estimate the reaction rate of CH ₄ in the pre-reaction unit 20. . The pressure control unit 50a calculates the difference between the target reaction rate and the estimated reaction rate of CH ₄ in the pre-reaction unit 20, and stores the control pressure of the booster 30 necessary to cover this difference in a storage unit (not shown). Determined from pre-stored control maps and estimation formulas. The pressure control unit 50a controls the booster 30 so that the pressure of the mixed gas stored in the storage unit 35 becomes the determined control pressure, and appropriately compresses the mixed gas before being stored in the storage unit 35. do.

According to the methane production apparatus 1 of the first embodiment described above, the mixed gas before being stored in the storage section 35 is placed upstream of the storage section 35 that stores the mixed gas to be supplied to the main reaction section 40. A pre-reaction section 20 is provided which is used to generate CH ₄ . The storage section 35 stores a mixed gas containing CH ₄ produced in the pre-reaction section 20 and unreacted CO ₂ and H ₂ in the pre-reaction section 20 . When _CH4 is produced from a mixed gas of _CO2 and H2, the _volume of the mixed gas containing _CH4 after the reaction is smaller than the volume of the mixed gas without _CH4 before the reaction. From this, when CH ₄ is generated in the pre-reaction section 20 using the mixed gas before being stored in the storage section 35, the volume of the mixed gas stored in the storage section 35 does not include the pre-reaction section 20. smaller than the case. Thereby, the storage part 35 can be made smaller. Moreover, since the volume of the mixed gas stored in the storage unit 35 is small, the power required for pressurization can be reduced. Therefore, it is possible to reduce the physical size of the apparatus while suppressing a decrease in system efficiency. The methane production apparatus ₁ of the _first embodiment is assumed to produce CH4, but the hydrocarbon compounds produced by the "hydrocarbon production apparatus" include not only CH4, but also carbon compounds such as ethane and propane. and hydrogen, and compounds containing primarily carbon and hydrogen.

Conventionally, when a storage unit is provided for temporarily storing the mixed gas used to generate the hydrocarbon compound, the pressure of the mixed gas stored in the storage unit is made higher than at least the pressure in the reaction unit, so that the reaction It becomes possible to control the supply amount of the mixed gas to the part. Since the volume of the mixed gas stored decreases as the pressure in the storage section increases, the storage section can be made smaller. However, the boosting power required to pressurize the mixed gas is increased, resulting in a decrease in system efficiency. On the other hand, if the size of the storage unit is increased, the system efficiency will be increased, but the size of the methane production apparatus will be increased. In the methane production apparatus 1 of the first embodiment, the mixed gas before being stored in the storage unit 35 is used to generate methane, thereby reducing the volume of the mixed gas. As a result, the mixed gas used in the main reaction section 40 can be stored in the relatively small storage section 35 without excessive pressure increase.

Further, according to the methane production apparatus 1 of the first embodiment, the condenser 25 is provided to separate moisture contained in the mixed gas before being stored in the storage section 35 from the mixed gas. As a result, moisture generated by the CH ₄ production reaction in the pre-reaction section 20 can be separated from the mixed gas before being stored in the storage section 35 . Therefore, since the volume of the mixed gas stored in the storage section 35 can be reduced, the storage section 35 can be made even smaller.

Moreover, according to the methane production apparatus 1 of the first embodiment, the booster 30 is provided to pressurize the mixed gas before being stored in the storage section 35 . As a result, the mixed gas stored in the storage unit 35 can be compressed before being stored in the storage unit 35, so that the volume of the mixed gas stored in the storage unit 35 can be further reduced. Therefore, since the storage section 35 can be made smaller, the size of the device can be made smaller.

Further, according to the methane production apparatus 1 of the first embodiment, the pressure control unit 50a uses the CO ₂ concentration of the mixed gas detected by the first CO ₂ concentration meter 46 to determine the reaction rate of CH ₄ in the pre-reaction unit 20. to estimate When the estimated reaction rate of CH ₄ in the pre-reaction section 20 is lower than the target reaction rate, the pressure control section 50a adjusts the mixed gas before being stored in the storage section 35 according to the difference between the estimated reaction rate and the target reaction rate. control the booster 30 so that the Accordingly, the storage section 35 having a size preset according to the target reaction rate can store the mixed gas supplied to the main reaction section 40 .

Further, according to the methane production apparatus 1 of the first embodiment, the pressure control section 50a uses the estimated reaction rate of CH ₄ in the pre-reaction section 20 to control the mixed gas supplied from the storage section 35 to the main reaction section 40. The pressure of the mixed gas can be modified so that the pressure of is within the expected variation in the main reactor 40 .

<Second embodiment>
FIG. 7 is an explanatory diagram showing a schematic configuration of the methane production device 2 in the second embodiment. In the methane production apparatus 2 of the second embodiment, compared with the methane production apparatus 1 (FIG. 1) of the first embodiment, the booster 60 arranged upstream of the storage section 35 is located upstream of the pre-reaction section 20. The difference is that it is located on the side.

The methane production apparatus 2 includes a first adsorption section 11, a second adsorption section 12, a hydrogen supply source 13, a supply channel 15, a booster 60, a pre-reaction section 20, a condenser 25, and a storage section. 35 , a main reaction section 40 , a first CO ₂ concentration meter 46 , a second CO ₂ concentration meter 47 and a control section 50 .

The booster 60 is provided on the upstream side of the pre-reaction section 20 in the supply channel 15, as shown in FIG. The booster 60 is electrically connected to the pressure control section 50a. The booster 60 appropriately boosts the pressure of the mixed gas supplied to the pre-reaction section 20 according to the command from the pressure control section 50a based on the CO ₂ concentration of the mixed gas detected by the first CO ₂ concentration meter 46 .

According to the methane production apparatus 2 of the second embodiment described above, the booster 60 provided on the upstream side of the pre-reaction section 20 in the supply channel 15 increases the mixed gas supplied to the pre-reaction section 20. Increase pressure. Thereby, the reaction rate of CH ₄ in the pre-reaction section 20 can be improved. Therefore, since the volume of the mixed gas stored in the storage section 35 can be further reduced, the volume of the storage section can be further reduced.

Further, according to the methane production apparatus 2 of the second embodiment, the pressure control unit 50a uses the CO ₂ concentration of the mixed gas detected by the first CO ₂ concentration meter 46 to determine the reaction rate of CH ₄ in the pre-reaction unit 20. presume. The pressure control section 50 a controls the booster 60 according to the difference between the target reaction rate and the estimated reaction rate in the pre-reaction section 20 . When the estimated reaction rate of CH ₄ in the pre-reaction section 20 is lower than the target reaction rate, the pressure control section 50 a controls the booster 60 so as to further compress the mixed gas supplied to the pre-reaction section 20 . Thereby, the reaction rate in the pre-reaction part 20 can be improved and the reaction rate can be set to the target reaction rate. Therefore, the storage section 35 having a size preset according to the target reaction rate can store the mixed gas supplied to the main reaction section 40 .

Further, according to the methane production apparatus 2 of the second embodiment, the methanation reaction at a higher pressure becomes possible in the pre-reaction section 20 by controlling the booster 60 by the pressure control section 50a. can be made smaller. This makes it possible to reduce the physical size of the device.

<Third Embodiment>
FIG. 8 is an explanatory diagram showing a schematic configuration of the methane production device 3 in the third embodiment. The methane production apparatus 3 of the third embodiment differs from the methane production apparatus 1 ( FIG. 1 ) of the first embodiment in that the heat medium flow rate flowing through the heat medium flow path 22 of the pre-reaction section 20 is controlled.

The methane production apparatus 3 includes a first adsorption section 11, a second adsorption section 12, a hydrogen supply source 13, a supply channel 15, a pre-reaction section 20, a condenser 25, a booster 30, and a storage section. 35 , a main reaction section 40 , a first CO ₂ concentration meter 46 , a second CO ₂ concentration meter 47 , a gas information acquisition section 65 and a control section 50 .

The gas information acquisition section 65 detects the H ₂ /CO ₂ concentration of the mixed gas and the flow rate of the mixed gas on the upstream side of the pre-reaction section 20 . Information related to the mixed gas detected by the gas information acquisition unit 65 is output to the flow control unit 50c included in the control unit 50 . The flow control unit 50c uses the H ₂ /CO ₂ concentration of the mixed gas and the flow rate of the mixed gas detected by the gas information acquisition unit 65 to adjust the flow rate of the heat medium flowing through the heat medium flow path 22 of the pre-reaction unit 20 to It is adjusted by controlling the heat medium flow rate regulator 66 .

FIG. 9 is an explanatory diagram showing the relationship between the H ₂ /CO ₂ concentration of the mixed gas supplied to the pre-reaction section 20 and the flow rate of the heat medium. In FIG. 9 , the horizontal axis indicates the H ₂ /CO ₂ concentration of the mixed gas supplied to the pre-reaction section 20 and the vertical axis indicates the relative flow rate of the heat medium supplied to the pre-reaction section 20 . In the relative flow rate of the heat medium shown on the vertical axis, the relative flow rate of the heat medium at the rated load is 1.0 when the H ₂ /CO ₂ concentration of the mixed gas is 4.0. As shown in _FIG . ₉ , it can be seen that the reaction rate of CH4 can be increased by increasing the flow rate of the heat transfer medium as the H2/ _CO2 concentration increases. This is because the temperature of the catalyst 21 in the pre-reaction section 20 can be adjusted to a proper temperature for the methanation reaction.

According to the methane production apparatus 3 of the third embodiment described above, using the H ₂ /CO ₂ concentration and flow rate of the mixed gas supplied to the pre-reaction section 20, the heat medium flow path 22 of the pre-reaction section 20 Adjust the flow rate of the heat medium flowing through the Since the methanation reaction in the pre-reaction section 20 is an exothermic reaction, the higher the temperature, the lower the reaction rate in terms of reaction equilibrium. Therefore, while it is necessary to cool the catalyst 21 to remove heat, excessive cooling deactivates the methanation reaction. Therefore, in the present embodiment, the temperature of the pre-reaction section 20 is set to the optimum temperature for the methanation reaction by controlling the flow rate of the heat medium corresponding to the H ₂ /CO ₂ concentration and flow rate of the mixed gas supplied to the pre-reaction section 20. , to increase the reaction rate in the pre-reaction section 20 . By adjusting the temperature of the pre-reaction section 20 with the flow rate of the heat medium in this way, the reaction rate in the pre-reaction section 20 can be increased, and the volume of the mixed gas stored in the storage section 35 can be further reduced. Therefore, the physical size of the device can be further reduced.

<Modification of this embodiment>
The present invention is not limited to the above-described embodiments, and can be implemented in various aspects without departing from the scope of the invention. For example, the following modifications are possible.

[Modification 1]
In the above-described embodiment, the methane production device as the 'hydrocarbon production device' produces CH ₄ as the 'hydrocarbon compound'. However, the hydrocarbon compounds produced by the hydrocarbon production equipment include not only _CH4 , but also compounds composed mainly of carbon and hydrogen, such as ethane and propane, and compounds mainly composed of carbon and hydrogen. may contain.

[Modification 2]
In the above-described embodiments, the methane production apparatus includes a condenser that separates moisture contained in the mixed gas from the mixed gas and a booster that pressurizes the mixed gas. However, it does not have to be equipped with a condenser or a booster.

[Modification 3]
In the above-described embodiment, CH ₄ is produced from CO ₂ and H ₂ recovered from exhaust gas using two adsorption units. However, the method of supplying CO ₂ is not limited to this. Also, the method of recovering CO ₂ from the exhaust gas using the adsorption section is not limited to the above-described embodiment.

[Modification 4]
In the first and second embodiments, information on the CO ₂ concentration of the mixed gas was acquired, and the reaction rate of the pre-reaction section 20 estimated from the CO ₂ concentration was used to control the booster. However, the information for controlling the booster is not limited to this. It may be the H ₂ concentration or CH ₄ concentration of the mixed gas.

[Modification 5]
The methane production apparatus 1 of the first embodiment may be provided with a booster 60 provided upstream of the pre-reaction section 20 of the second embodiment. In this case, the booster 60 is used to promote the improvement of the reaction rate in the pre-reaction section 20, while the booster 30 is used to reduce the volume of the mixed gas stored in the storage section 35. .

[Modification 6]
The method of improving the reaction rate of the pre-reaction section 20 based on the information acquired by the gas information acquisition section 65 of the third embodiment may be applied to the second embodiment.

[Modification 7]
In the third embodiment, the gas information acquiring section 65 detects the H ₂ /CO ₂ concentration of the mixed gas and the flow rate of the mixed gas on the upstream side of the pre-reaction section 20 . However, the information acquired by the gas information acquisition unit 65 is not limited to this. Only the H ₂ /CO ₂ concentration of the mixed gas or the flow rate of the mixed gas may be used, and any information that enables estimation of the reaction rate of CH ₄ in the pre-reaction section 20 may be used.

The present aspect has been described above based on the embodiments and modifications, but the above-described embodiments are intended to facilitate understanding of the present aspect, and do not limit the present aspect. This aspect may be modified and modified without departing from the spirit and scope of the claims, and this aspect includes equivalents thereof. Also, if the technical features are not described as essential in this specification, they can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 1, 2, 3, 4... Methane production apparatus 5... Exhaust gas supply source 6... Dehydration part 10a... Reaction part 10b, 25... Condenser 11... First adsorption part 11a, 12a... Adsorbent 12... Second adsorption part 13 Hydrogen supply source 13a, 13b Hydrogen channel 13c, 30, 60 Booster 13d Flow controller 15 Supply channel 16 Produced gas channel 20 Pre-reaction part 21, 41 Catalyst 22, 42 Heat Medium flow path 35 Storage unit 40 Main reaction unit 46 First CO ₂ concentration meter 47 Second CO ₂ concentration meter 48 Flow controller 50 Control unit 50 a Pressure control unit 50 b, 50 c Flow control unit 65 Gas Information acquisition unit 66... Heat medium flow controller

Claims (8)

A hydrocarbon production device,
a main reaction section that produces a hydrocarbon compound using carbon dioxide and hydrogen;
a supply channel through which a mixed gas containing carbon dioxide and hydrogen to be supplied to the main reaction section flows;
a storage section provided on the supply channel for storing the mixed gas before being supplied to the main reaction section;
a pre-reaction unit provided upstream of the storage unit in the supply channel and generating a hydrocarbon compound using the mixed gas before being stored in the storage unit;
The storage unit stores the mixed gas containing the hydrocarbon compound produced in the pre-reaction unit,
Hydrocarbon production equipment. The hydrocarbon production apparatus according to claim 1 further comprises
provided between the pre-reaction section and the storage section in the supply flow path, and mixes the high boiling point components contained in the mixed gas taken out from the pre-reaction section and before being stored in the storage section; comprising a separation unit that separates from the gas,
Hydrocarbon production equipment. The hydrocarbon production apparatus according to claim 1 or claim 2 further comprises
A downstream pressurizing section provided between the pre-reaction section and the storage section in the supply flow path for pressurizing the mixed gas before being stored in the storage section,
Hydrocarbon production equipment. The hydrocarbon production apparatus according to claim 3 further comprises
a first concentration information acquisition unit provided between the pre-reaction unit and the storage unit for acquiring information related to the concentration of the mixed gas;
a downstream pressure control unit that adjusts the pressure of the mixed gas stored in the storage unit by controlling the downstream pressure increasing unit using the information acquired by the first concentration information acquisition unit. ,
Hydrocarbon production equipment. The hydrocarbon production apparatus according to any one of claims 1 to 4 further comprises
An upstream pressurizing section provided upstream of the pre-reaction section on the supply flow path and pressurizing the mixed gas supplied to the pre-reaction section,
Hydrocarbon production equipment. The hydrocarbon production apparatus according to claim 5 further comprises
a second concentration information acquisition unit provided between the pre-reaction unit and the storage unit for acquiring information related to the concentration of the mixed gas;
an upstream pressure control unit that adjusts the pressure of the mixed gas supplied to the pre-reaction unit by controlling the upstream pressure increasing unit using the information acquired by the second concentration information acquisition unit; prepare
Hydrocarbon production equipment. The hydrocarbon production apparatus according to any one of claims 1 to 6,
The pre-reaction part is formed with a heat medium flow path through which a heat medium for recovering the reaction heat of the formation of the hydrocarbon compound in the pre-reaction part flows,
The hydrocarbon production device further comprises:
a gas information acquisition unit that acquires information related to the concentration or flow rate of the mixed gas supplied to the pre-reaction unit;
a flow rate adjustment unit that adjusts the flow rate of the heat medium flowing through the heat medium flow path;
a flow rate control unit that controls the flow rate adjustment unit using the information acquired by the gas information acquisition unit;
Hydrocarbon production equipment. A hydrocarbon production method comprising:
A pre-reaction step of producing a hydrocarbon compound using a mixed gas containing carbon dioxide and hydrogen;
a storage step of storing the mixed gas containing the hydrocarbon compound produced in the pre-reaction step;
a reaction step of producing a hydrocarbon compound using the mixed gas stored in the storage step;
Hydrocarbon production method.

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