JP2017052669A - System with water vapor modification circuit and methanation circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system with a water vapor modification circuit and a methanation circuit each of which can operate without using an expensive compressor excellent in heat resistance.SOLUTION: The system with a water vapor modification circuit and a methanation circuit is provided, in which a water vapor modification circuit (1) comprises a water vapor modification reactor (R1), a first heater (H1) and a first heat exchanger (HX1), a methanation circuit (2) comprises a methanation reactor (R2), a second heater (H2) and a second heat exchanger (HX2). The first heater (HX1) heats a hydrogen-rich medium in such a way that a temperature of the hydrogen-rich medium becomes a temperature enabling a temperature of a medium before the first reaction to elevate to a reaction temperature at which the water vapor modification is performed, and the second heater (HX2) heats a methane-rich medium in such a way that the temperature of the methane-rich medium becomes a temperature enabling a temperature of a medium before the second reaction to elevate to a reaction temperature at which the methanation is performed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a system including a steam reforming circuit and a methanation circuit.

  Conventionally, steam reforming in which hydrocarbon and steam are reacted is known as a method for generating hydrogen, and methanation in which carbon monoxide or carbon dioxide is reacted with hydrogen is known as a method for generating methane. ing. For example, Patent Document 1 discloses a system including a steam reforming circuit that performs steam reforming and a methanation circuit that performs methanation.

  The steam reforming circuit has a first compressor, a steam reforming reactor, and a first heat exchanger. The first compressor compresses the first pre-reaction medium containing hydrocarbons and water vapor. Specifically, in the first compressor, the first pre-reaction medium is compressed so that the temperature of the first pre-reaction medium rises to a reaction temperature at which steam reforming is effectively performed in the steam reforming reactor. Is done. The steam reforming reactor causes steam reforming to generate a hydrogen-rich medium mainly composed of hydrogen by reacting the hydrocarbon in the first pre-reaction medium discharged from the first compressor with steam. Reactor. The first heat exchanger heats the first pre-reaction medium by exchanging heat between the hydrogen-rich medium flowing out of the steam reforming reactor and the first pre-reaction medium before flowing into the first compressor. Note that the hydrogen-rich medium flowing out from the first heat exchanger is recovered through the cooler and the gas-liquid separator.

  The methanation circuit has a methanation reactor, a second compressor, and a second heat exchanger. The methanation reactor is a reactor that performs methanation to produce a methane-rich medium mainly composed of methane by reacting carbon monoxide or carbon dioxide with hydrogen. The second compressor compresses the methane rich medium produced in the methanation reactor. The second heat exchanger heats the methane-rich medium discharged from the second compressor and the second pre-reaction medium (medium containing carbon monoxide, carbon dioxide, and hydrogen) before flowing into the methanation reactor. The second pre-reaction medium is heated by exchanging. Specifically, in the second heat exchanger, the second pre-reaction medium is heated by the methane-rich medium so that the temperature of the second pre-reaction medium becomes a reaction temperature at which methanation is effectively performed in the methanation reactor. The In other words, in the second compressor, the temperature of the methane-rich medium flowing out from the methanation reactor can increase the temperature of the second pre-reaction medium to the reaction temperature in the second heat exchanger. The methane rich medium is compressed to reach temperature. Note that the methane-rich medium flowing out from the second heat exchanger is recovered by a cooler after being expanded by an expander.

Yuhei Koyanagi and 4 others, "Application of chemical heat transformer for coproduction system", [online], CHEMICAL ENGINEERING TRANSACTIONS, August 2010, No. 21, p. 55-60, [Search May 8, 2015], Internet <URL: http://www.aidic.it/cet/10/21/010.pdf>

  In the system described in Document 1, the first compressor and the second compressor need to have excellent heat resistance. Specifically, since the reaction temperature at which steam reforming is effectively performed in the steam reforming reactor is high, the first compressor that compresses the first pre-reaction medium flowing into the steam reforming reactor is excellent. Must have heat resistance. Similarly, since the reaction temperature at which methanation is effectively performed in the methanation reactor is high, the second compressor that compresses the methane-rich medium flowing out of the methanation reactor has excellent heat resistance. There is a need. In order to manufacture such a compressor, that is, a compressor having excellent heat resistance, an expensive material that is difficult to process is required.

  An object of the present invention is to provide a system including a steam reforming circuit and a methanation circuit that can be operated without using an expensive compressor having excellent heat resistance.

  As means for solving the above problems, the present invention comprises a steam reforming circuit that performs steam reforming and a methanation circuit that performs a methanation reaction, and the steam reforming circuit includes hydrocarbon and steam. A steam reforming reactor for performing a steam reforming to produce a hydrogen-rich medium mainly composed of hydrogen by reacting with water, and supplying heat from the outside to the hydrogen-rich medium flowing out of the steam reforming reactor A first heater that heats the hydrogen-rich medium, a hydrogen-rich medium that has flowed out of the first heater, a hydrocarbon and steam, and the first heater before flowing into the steam reforming reactor. A first heat exchanger that heats the first pre-reaction medium by exchanging heat with the pre-reaction medium, and the methanation circuit includes at least one of carbon monoxide and carbon dioxide. A methanation reactor for performing methanation to produce a methane-rich medium mainly composed of methane by reacting with the element, and supplying heat from the outside to the methane-rich medium flowing out of the methanation reactor A methane-rich medium flowing out of the second heater, at least one of carbon monoxide and carbon dioxide, and hydrogen, and flowing into the methanation reactor A second heat exchanger that heats the second pre-reaction medium by exchanging heat with the second pre-reaction medium before the first reaction medium, wherein the first heater is from the steam reforming reactor. The temperature of the hydrogen-rich medium flowing out increases the temperature of the first pre-reaction medium in the first heat exchanger to a reaction temperature at which steam reforming is performed in the steam reforming reactor. The hydrogen-rich medium is heated to a temperature that can be heated, and the second heater has a temperature of the methane-rich medium flowing out of the methanation reactor in the second heat exchanger. (2) A steam reforming circuit and a methanation circuit for heating the methane-rich medium so that the temperature of the pre-reaction medium can be increased to a reaction temperature at which the methanation is performed in the methanation reactor. A system is provided.

  In this system, the hydrogen-rich medium flowing out from the steam reforming reactor flows into the first heat exchanger after being heated by the first heater, and the methane-rich medium flowing out from the methanation reactor is After being heated by the two heaters, it flows into the second heat exchanger. Therefore, in order to further increase the temperature of the high-temperature hydrogen-rich medium flowing out from the steam reforming reactor, the compressor that compresses the hydrogen-rich medium or the high-temperature methane-rich medium flowing out of the methanation reactor is further increased Therefore, it is possible to operate without using a compressor that compresses the methane-rich medium, that is, an expensive compressor having excellent heat resistance.

  In this case, it further comprises an enclosure having a shape surrounding the methanation reactor and the heat transfer space around the methanation reactor, and the methanation reactor comprises methanation in the methanation reactor. It is preferable that the heat of reaction at the time be transmitted to the heat transfer space.

  In this aspect, the radiant heat of the reaction heat at the time of methanation in the methanation reactor can be effectively used in the enclosure.

  Furthermore, in this case, it is preferable to further include a control unit that adjusts the supply amount of the second pre-reaction medium to the methanation reactor so that the temperature of the heat transfer space falls within a target range.

  In this way, the amount of supply of the second pre-reaction medium to the methanation reactor, that is, the amount of heat of reaction at the time of methanation is adjusted so that the temperature of the heat transfer space falls within the target range. The heat of reaction during methanation can be recovered stably in the heat space.

  Specifically, a second supply channel that supplies the second pre-reaction medium to the methanation reactor, a second compressor that is provided in the second supply channel, and a second supply channel that are provided in the second supply channel. A second opening / closing valve, wherein the controller is configured such that the temperature of the heat transfer space is lower than a lower limit value of the target range, and the second pre-reaction medium of the second supply flow path When the flow rate is smaller than a specified amount, the rotational speed of the second compressor is increased, the opening of the second on-off valve is increased, and the heating amount of the methane-rich medium in the second heater is increased. The second compression when the temperature of the heat transfer space is smaller than the lower limit value of the target range and the flow rate of the second pre-reaction medium in the second supply flow path is larger than the specified amount. Lowering the rotational speed of the machine and reducing the opening of the second on-off valve, and When the heating amount of the methane-rich medium in the two heaters is increased and the temperature of the heat transfer space is larger than the upper limit value of the target range, the second compressor is lowered and the second on-off valve It is preferable to reduce the amount of heating of the methane-rich medium in the second heater.

  Moreover, in this invention, it is preferable to further provide the 1st expander which expands the hydrogen rich medium which flowed out from the said 1st heat exchanger, and the 1st power recovery machine connected to the said 1st expander.

  If it does in this way, the energy which a hydrogen rich medium has can be effectively collect | recovered with a 1st power recovery device via a 1st expander.

  Moreover, in this invention, it is preferable to further provide the 2nd expander which expands the methane rich medium which flowed out from the said 2nd heat exchanger, and the 2nd power recovery machine connected to the said 2nd expander.

  If it does in this way, the energy which a methane rich medium has can be effectively collected with the 2nd power recovery machine via the 2nd expansion machine.

  As described above, according to the present invention, it is possible to provide a system including a steam reforming circuit and a methanation circuit that can be operated without using an expensive compressor having excellent heat resistance.

It is a figure which shows the outline of a structure of the system provided with the steam reforming circuit and methanation circuit of one Embodiment of this invention. It is a figure which shows the relationship between a methanation reactor and an enclosure part. It is sectional drawing in the III-III line of FIG. It is a flowchart which shows the control content of a control part. It is a table | surface which shows the outline | summary of the control content of a control part. It is a figure which shows the outline of a structure of the modification of the system shown in FIG.

  A system including a steam reforming circuit and a methanation circuit according to an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the present system includes a steam reforming circuit 1 and a methanation circuit 2.

  The steam reforming circuit 1 includes a steam reforming reactor R1, a first supply channel S11, a first recovery channel S12, a first heater H1, a first heat exchanger HX1, and a first gas / liquid. It has a separator F1, a first expander EX1, and a first power recovery machine G1.

  The first supply channel S11 is a channel that supplies a medium containing hydrocarbons and steam (hereinafter referred to as “first pre-reaction medium”) to the steam reforming reactor R1. In the present embodiment, a medium containing methane and water vapor is supplied as the first pre-reaction medium.

  The steam reforming reactor R1 is a reaction for performing steam reforming to generate a hydrogen-rich medium (medium containing hydrogen as a main component) by reacting the hydrocarbon supplied from the first supply channel S11 with steam. It is a vessel. This reaction is an endothermic reaction. In this embodiment, the heat required for steam reforming is supplied from an external heat source. A catalyst is disposed in the steam reforming reactor R1.

  The first recovery channel S12 is a channel for recovering the hydrogen-rich medium that has flowed out of the steam reforming reactor R1.

  The first heater H1 is provided in the first recovery flow path S12. The first heater H1 heats the hydrogen-rich medium by supplying heat from the outside to the hydrogen-rich medium flowing out from the steam reforming reactor R1. In the present embodiment, an electric heater is used as the first heater H1. However, a combustion heater or an IH heater may be used as the first heater H1.

  The first heat exchanger HX1 exchanges heat between the hydrogen-rich medium flowing out from the first heater H1 and the first pre-reaction medium before flowing into the steam reforming reactor R1, thereby allowing the first pre-reaction medium to be exchanged. Heat. That is, the first heat exchanger HX1 is provided at a portion where the first supply channel S11 and the first recovery channel S12 intersect. In the first heat exchanger HX1, the first pre-reaction medium is heated by the hydrogen-rich medium so that the temperature of the first pre-reaction medium becomes a reaction temperature at which steam reforming is effectively performed in the steam reforming reactor R1. Is done. In other words, in the first heater H1, the temperature of the hydrogen-rich medium flowing out from the steam reforming reactor R1 can increase the temperature of the first pre-reaction medium to the reaction temperature in the first heat exchanger HX1. The hydrogen rich medium is heated to a possible temperature.

  The 1st gas-liquid separator F1 is provided in the site | part in the downstream of 1st heat exchanger HX1 among 1st collection | recovery flow paths S12. The first gas-liquid separator F1 separates moisture (unreacted portion of the first reaction medium) from the hydrogen-rich medium. This moisture is discharged through the heat exchanger HX4.

  The first expander EX1 expands the hydrogen-rich medium that has flowed out of the first gas-liquid separator F1. In other words, the first expander EX1 is driven by the energy of the hydrogen-rich medium. The hydrogen-rich medium flowing out from the first expander EX1 is recovered via the heat exchanger HX3. The first gas-liquid separator F1, the first expander EX1, the heat exchanger HX3, and the heat exchanger HX4 do not require gas separation and can be omitted when power recovery is not performed.

  The first power recovery machine G1 is connected to the first expander EX1. That is, the first power recovery machine G1 recovers the energy of the hydrogen-rich medium flowing out from the first gas-liquid separator F1 via the first expander EX1. In the present embodiment, a generator is used as the first power recovery machine G1.

  In the present embodiment, a first on-off valve V1 and a first compressor C1 are provided in a portion of the first supply flow path S11 upstream of the first heat exchanger HX1. The first on-off valve V1 is an on-off valve whose opening degree can be adjusted. The first compressor C1 can adjust the rotation speed, and sends the first pre-reaction medium toward the steam reforming reactor R1. That is, the first on-off valve V1 and the first compressor C1 function as a flow rate adjusting unit that adjusts the supply amount of the first pre-reaction medium to the steam reforming reactor R1.

  The methanation circuit 2 includes a methanation reactor R2, a second supply channel S21, a second recovery channel S22, a second heater H2, a second heat exchanger HX2, and a second gas-liquid separator. It has F2, 2nd expansion machine EX2, and 2nd power recovery machine G2.

  The second supply flow path S21 is a flow path for supplying a medium containing at least one of carbon monoxide and carbon dioxide and hydrogen (hereinafter referred to as “second pre-reaction medium”) to the methanation reactor R2. is there. In the present embodiment, a medium containing carbon monoxide and hydrogen is supplied as the second pre-reaction medium.

  The methanation reactor R2 reacts at least one of carbon monoxide and carbon dioxide supplied from the second supply flow path S21 with hydrogen to generate a methane-rich medium (medium containing methane as a main component). It is a reactor that allows nations to perform. This reaction is an exothermic reaction. In this embodiment, the heat generated during methanation is effectively recovered. This point will be described later. A catalyst is disposed in the methanation reactor R2.

  The second recovery channel S22 is a channel for recovering the methane-rich medium that has flowed out of the methanation reactor R2.

  The second heater H2 is provided in the second recovery channel S22. The second heater H1 heats the methane-rich medium by supplying heat from the outside to the methane-rich medium flowing out from the methanation reactor R2. In the present embodiment, an electric heater is used as the second heater H2. However, a combustion heater or an IH heater may be used as the second heater H2.

  The second heat exchanger HX2 heat-exchanges the methane-rich medium flowing out from the second heater H2 and the second pre-reaction medium before flowing into the methanation reactor R2, thereby changing the second pre-reaction medium. Heat. That is, the second heat exchanger HX2 is provided at a portion where the second supply channel S21 and the second recovery channel S22 intersect. In the second heat exchanger HX2, the second pre-reaction medium is heated by the methane-rich medium so that the temperature of the second pre-reaction medium becomes a reaction temperature at which the methanation is effectively performed in the methanation reactor R2. . In other words, in the second heater H2, the temperature of the methane-rich medium flowing out of the methanation reactor R2 can increase the temperature of the second pre-reaction medium to the reaction temperature in the second heat exchanger HX2. The methane rich medium is heated to a temperature that becomes

  The second gas-liquid separator F2 is provided at a site downstream of the second heat exchanger HX2 in the second recovery flow path S22. The second gas-liquid separator F2 separates water (water generated during methanation) from the methane-rich medium. This moisture is discharged through the heat exchanger HX7.

  The second expander EX2 expands the methane-rich medium that has flowed out of the second gas-liquid separator F2. In other words, the second expander EX2 is driven by the energy of the methane-rich medium. The methane-rich medium flowing out from the second expander EX2 is recovered via the heat exchanger HX6. The second gas-liquid separator F2, the second expander EX2, the heat exchanger HX6, and the heat exchanger HX7 do not need to be gas separated and can be omitted when power recovery is not performed.

  The second power recovery machine G2 is connected to the second expander EX2. That is, the second power recovery machine G2 recovers the energy of the methane-rich medium flowing out from the second gas-liquid separator F2 via the second expander EX2. In the present embodiment, a generator is used as the second power recovery machine G2.

  In the present embodiment, a second on-off valve V2 and a second compressor C2 are provided in a portion of the second supply flow path S21 upstream of the second heat exchanger HX2. The second on-off valve V2 is an on-off valve whose opening degree can be adjusted. The second compressor C2 can adjust the rotation speed, and sends the second pre-reaction medium toward the methanation reactor R2. That is, the second on-off valve V2 and the second compressor C2 function as a flow rate adjusting unit that adjusts the supply amount of the second pre-reaction medium to the methanation reactor R2.

  Moreover, in this embodiment, the site | part between 1st compressor C1 and 1st heat exchanger HX1 among 1st supply flow paths S11, 2nd heat exchanger HX2 and 2nd among 2nd collection | recovery flow paths S22. A fifth heat exchanger HX5 is provided at a portion where the portion between the two gas-liquid separator F2 intersects. The fifth heat exchanger HX5 performs the first reaction by exchanging heat between the first pre-reaction medium before flowing into the first heat exchanger HX1 and the methane-rich medium after flowing out from the second heat exchanger HX2. The previous medium is heated. In this aspect, the thermal energy of the methane-rich medium after flowing out from the second heat exchanger HX2 (after heat is applied to the second pre-reaction medium in the second heat exchanger HX2) is the first heat exchanger HX1. Therefore, the heating amount of the first pre-reaction medium in the first heat exchanger HX1, that is, the heating amount in the first heater H1, is reduced. Therefore, the thermal efficiency of the entire system is improved.

  Here, recovery of reaction heat at the time of methanation in the methanation reactor R2 will be described.

  As shown in FIGS. 1 to 3, the present embodiment includes an enclosing portion 3 that encloses the methanation reactor R <b> 2 and the surrounding heat transfer space. 2 and 3 show an example in which a plurality (14 in this embodiment) methanation reactors R2 are arranged in the enclosure 3. Each methanation reactor R2 is arranged so as to be intermittently arranged along one direction (left-right direction in FIG. 3). 2 and 3, the inside of the methanation reactor R2 arranged on the upper side communicates with the inside of the methanation reactor R2 arranged on the lower side of the figure. Each methanation reactor R2 is configured to be able to transfer reaction heat during methanation in the methanation reactor R2 to the heat transfer space. In this embodiment, each methanation reactor R2 is formed of a radiant tube. Further, a heating furnace is used as the surrounding portion 3. Specifically, a material to be heat-treated (steel material or the like) is passed along one direction between each methanation reactor R2 (heat transfer space) arranged above and below. Thereby, the material to be heat-treated is heat-treated by radiant heat from each methanation reactor R2. The enclosure 3 is divided into four zones (spaces). Four methanation reactors R2 are arranged in the first zone and the second zone, respectively, and three methanation reactors are arranged in the third zone and the fourth zone, respectively. Each zone is provided with a temperature sensor 5 capable of detecting the temperature of the zone.

The system further includes a control unit 4. The controller 4 adjusts the supply amount of the second pre-reaction medium to the methanation reactor R2 so that the temperature of the heat transfer space in the enclosure 3 falls within the target range. In the present embodiment, the control unit 4 adjusts the supply amount of the second pre-reaction medium to the methanation reactor R2 so that the temperature of the heat transfer space becomes the set temperature T _SV . Moreover, the control part 4 adjusts the heating amount in the 1st heater H1, and the heating amount in the 2nd heater H2. Hereinafter, the control content of the control unit 4 will be described with reference to FIG.

When the operation of this system is started, the control unit 4 detects the temperature _{Ths of the} external heat source that supplies heat to the steam reforming reactor R1, and based on this value, determines the outlet pressure of the first compressor C1. Determine (step ST11). Since the reaction temperature in the steam reforming reactor R1 is determined by the pressure of the first pre-reaction medium, the first compressor C1 uses the pressure of the first pre-reaction medium (water vapor) based on the temperature _{Ths of the} external heat source. The reaction temperature in the reforming reactor R1) is determined. The temperature _Ths of the external heat source is detected by the temperature sensor 6 that can detect the temperature of the external heat source, and the outlet pressure of the first compressor C1 is the same as that of the first compressor C1 in the first supply flow path S11. It is detected by a pressure sensor 7 provided at a site between the fifth heat exchanger HX5.

Next, the control unit 4 reads the set temperature T _SVi set for each zone and the set flow rate Q _{SVi, S21} of the second pre-reaction medium set for each zone (step ST12). “I” is a number corresponding to a zone.

Subsequently, the control unit 4 performs the actual temperature T _{PVi that} is the current temperature of the heat transfer space, the first actual flow rate Q _{PVi, S11 that} is the current flow rate of the first supply flow path S11 _, and the current second supply. The second actual flow rate Q _{PVi, S21} which is the flow rate of the flow path S21 is detected (step ST13). The first actual flow rate Q _{PVi, S11} is detected by the flow meter 8 provided in the first supply flow path S11, and the second actual flow rate Q _{PVi, S21} is the flow rate provided in the second supply flow path S21. A total of 9 is detected.

Thereafter, the control unit 4 determines whether or not a value obtained by subtracting the actual temperature T _PVi from the set temperature T _SVi is larger than 0 (step ST14).

As a result, when the value obtained by subtracting the actual temperature T _PVi from the set temperature T _SVi is larger than 0 (YES in step ST14), the control unit 4 changes the second actual flow rate Q _{PVi, S21} from the set flow rate Q _{SVi, S21} . It is determined whether or not the subtracted value is greater than 0 (step ST15). As a result, when the value obtained by subtracting the second actual flow rate Q _{PVi , S21} from the set flow rate Q _{SVi, S21} is larger than 0 (YES in step ST15), the control unit 4 determines that the first actual flow rate Q _{PVi, S11} and the first actual flow rate Q _{PVi, S11 2In} order to increase the actual flow rate Q _{PVi, S21} , the opening degree of the first on-off valve V1 and the rotational speed NC1 of the first compressor _C1 are increased, and the opening degree of the second on-off valve V2 and the second compressor The rotation speed N _C2 of _C2 is increased, and further, the heating amount in the first heater H1 and the heating amount in the second heater H2 are increased (step ST16), and the process returns to step ST12. On the other hand, when the value obtained by subtracting the second actual flow rate Q _{PVi , S21} from the set flow rate Q _{SVi, S21} is 0 or less (NO in step ST15), the control unit 4 determines the second actual flow rate Q from the set flow rate Q _{SVi, S21} . _It is determined whether or not the value obtained by subtracting _{PVi, S21} is smaller than 0 (step ST17).

As a result, when the value obtained by subtracting the second actual flow rate Q _{PVi , S21} from the set flow rate Q _{SVi, S21} is smaller than 0 (YES in step ST17), the control unit 4 determines that the first actual flow rate Q _{PVi, S11} and the first actual flow rate Q _{PVi, S11} (2) In order to reduce the actual flow rate Q _{PVi, S21} , the opening degree of the first on-off valve V1 and the rotational speed NC1 of the first compressor _C1 are reduced, and the opening degree of the second on-off valve V2 and the second compressor The rotational speed N _C2 of _C2 is decreased, the heating amount in the first heater H1 and the heating amount in the second heater H2 are increased (step ST18), and the process returns to step ST12. On the other hand, when the value obtained by subtracting the second actual flow rate Q _{PVi , S21} from the set flow rate Q _{SVi, S21} is not smaller than 0 (NO in step ST17), that is, the set flow rate Q _{SVi, S21} and the second actual flow rate Q _{PVi. , S21} are equal, the control unit 4 returns to step ST12.

In step ST14, when the value obtained by subtracting the actual temperature T _PVi from the set temperature T _SVi is 0 or less (NO in step ST14), the control unit 4 obtains a value obtained by subtracting the actual temperature T _PVi from the set temperature T _SVi. It is determined whether or not it is smaller than 0 (step ST19). As a result, when the value obtained by subtracting the actual temperature T _PVi from the set temperature T _SVi is smaller than 0 (YES in step ST19), the control unit 4 performs the first actual flow Q _{PVi, S11} and the second actual flow Q _{PVi, In} order to reduce _S21 , the opening degree of the first on-off valve V1 and the rotational speed N _C1 of the first compressor _C1 are reduced, and the opening degree of the second on-off valve V2 and the rotational speed N _C2 of the second compressor C2 are reduced. Further, the heating amount in the first heater H1 and the heating amount in the second heater H2 are reduced (step ST20), and the process returns to step ST12. On the other hand, when the value obtained by subtracting the actual temperature T _PVi from the set temperature T _SVi is not smaller than 0 (NO in step ST19), that is, when the set temperature T _SVi and the actual temperature T _PVi are equal, the control unit 4 The process returns to step ST12.

FIG. 5 shows an outline of the control contents of the control unit 4 described above. That is, when the actual temperature T _PVi is lower than the set temperature T _SVi and the second actual flow rate Q _{PVi, S21} is smaller than the set flow rate Q _{SVi, S21} , the control unit 4 has the first actual flow rate Q _{PVi, S11.} And various apparatus is adjusted so that 2nd performance flow volume _{QPVi, S21} may be increased and the temperature of each pre-reaction medium may be increased. Specifically, the control unit 4 increases the opening degree of the first on-off valve V1 and the rotational speed N _C1 of the first compressor _C1, and at the same time increases the opening degree of the second on-off valve V2 and the rotation of the second compressor C2. The number N _C2 is increased, and further, the heating amount in the first heater H1 and the heating amount in the second heater H2 are increased (step ST16).

Further, when the actual temperature T _PVi is lower than the set temperature T _SVi and the second actual flow rate Q _{PVi, S21} is larger than the set flow rate Q _{SVi, S21} , the control unit 4 determines that the first actual flow rate Q _{PVi, S11} and Various devices are adjusted so as to decrease the second actual flow rate Q _{PVi, S21} and increase the temperature of each pre-reaction medium. Specifically, the control unit 4 decreases the opening degree of the first on-off valve V1 and the rotation speed N _C1 of the first compressor C1, and at the same time, the opening degree of the second on-off valve V2 and the rotation of the second compressor C2. The number N _C2 is decreased, and further, the heating amount in the first heater H1 and the heating amount in the second heater H2 are increased (step ST18).

When the actual temperature T _PVi is higher than the set temperature T _SVi , the control unit 4 controls the first actual flow Q _PVi, regardless of the relationship between the second actual flow Q _{PVi, S21} and the set flow Q _{SVi, S21 .} Various devices are adjusted so as to decrease _S11 and the second actual flow rate Q _{PVi, S21 and} to decrease the temperature of each pre-reaction medium. Specifically, the control unit 4 decreases the opening degree of the first on-off valve V1 and the rotation speed N _C1 of the first compressor C1, and at the same time, the opening degree of the second on-off valve V2 and the rotation of the second compressor C2. The number N _C2 is decreased, and further, the heating amount in the first heater H1 and the heating amount in the second heater H2 are decreased (step ST20).

  Next, the operation of this system will be described.

  In the steam reforming circuit 1, the first pre-reaction medium is supplied to the steam reforming reactor R1 through the first supply flow path S11. Then, steam reforming is performed in the steam reforming reactor R1. Specifically, by receiving supply of heat necessary for steam reforming from an external heat source, hydrocarbon (methane) and steam react to generate a hydrogen-rich medium mainly composed of hydrogen. After this hydrogen-rich medium is heated by the first heater H1, the first pre-reaction medium in the first supply flow path S11 is heated in the first heat exchanger HX1. As a result, the temperature of the first pre-reaction medium flowing into the steam reforming reactor R1 rises to a reaction temperature at which steam reforming is effectively performed in the steam reforming reactor R1. The hydrogen-rich medium flowing out from the first heat exchanger HX1 is recovered through the first gas-liquid separator F1, the first expander EX1, and the heat exchanger HX3.

  On the other hand, in the methanation circuit 2, the second pre-reaction medium is supplied to the methanation reactor R2 through the second supply channel S21. Then, methanation is performed in the methanation reactor R2. Specifically, carbon monoxide and hydrogen react to produce a methane-rich medium mainly composed of methane. The heat-treated material is heat-treated in the surrounding portion 3 by the reaction heat generated at this time. The methane-rich medium produced in the methanation reactor R2 is heated by the second heater H2, and then the second pre-reaction medium in the second supply flow path S21 is heated in the second heat exchanger HX2. As a result, the temperature of the second pre-reaction medium flowing into the methanation reactor R2 rises to a reaction temperature at which methanation is effectively performed in the methanation reactor R2. The methane-rich medium flowing out from the second heat exchanger HX2 heats the first pre-reaction medium in the first supply flow path S11 in the fifth heat exchanger HX5. The methane-rich medium flowing out from the fifth heat exchanger HX5 is recovered through the second gas-liquid separator F2, the second expander EX2, and the heat exchanger HX6.

  As described above, in this system, the hydrogen-rich medium flowing out from the steam reforming reactor R1 is heated by the first heater H1 and then flows into the first heat exchanger HX1, and the methanation reaction The methane-rich medium flowing out from the vessel R2 is heated by the second heater H2 and then flows into the second heat exchanger HX2. Therefore, a compressor for compressing the high-temperature hydrogen-rich medium flowing out from the steam reforming reactor R1 and a high-temperature methane-rich medium flowing out from the methanation reactor R2 to further increase the temperature Therefore, the system can be operated without using a compressor for compressing the methane-rich medium, that is, an expensive compressor having excellent heat resistance.

  Further, in this embodiment, the enclosure portion 3 (heating furnace) having a shape surrounding the methanation reactor R2 and the heat transfer space is provided, and the methanation reactor R2 is configured by a radiant tube. 3, the radiant heat of the reaction heat at the time of methanation in the methanation reactor R2 can be used effectively.

In addition, the control unit 4 supplies the second pre-reaction medium supply to the methanation reactor R2, that is, the reaction during methanation, so that the temperature of the heat transfer space in the enclosure 3 becomes the set temperature T _SVi. Since the amount of heat is adjusted, the heat treatment of the heat-treated material in the heat transfer space is stabilized.

  In the present embodiment, since the first expander EX1 and the first power recovery machine G1 are provided, the energy of the hydrogen-rich medium is effective in the first power recovery machine G1 via the first expander EX1. Can be recovered.

  Similarly, since the second expander EX2 and the second power recovery machine G2 are provided, the energy of the methane-rich medium is effectively recovered by the second power recovery machine G2 via the second expander EX2. Can do.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the said embodiment, although the heating furnace was illustrated as the surrounding part 3, the surrounding part 3 is not restricted to a heating furnace.

  Moreover, as FIG. 6 shows, the 5th heat exchanger HX5 may be abbreviate | omitted.

  Hereinafter, the Example of the system provided with the steam reforming circuit and methanation circuit of the said embodiment is described with a comparative example.

  First, examples will be described. In this example, the flow rate of the first pre-reaction medium supplied through the first supply flow path S11 is 7.2 kg-mol / hr, and the composition of methane and water vapor in the first pre-reaction medium is set to 50%, respectively. Has been. Further, the flow rate of the second pre-reaction medium supplied through the second supply flow path S21 is 16.09 kg-mol / hr, and the compositions of carbon monoxide and hydrogen in the second pre-reaction medium are 25% and 75, respectively. % Is set. The pressure after the reaction is set so that the equilibrium constant is 1.

  In the steam reforming circuit 1, the first pre-reaction medium supplied in the state of 300K and 0.1 MPa in the first supply flow path S11 is heated in the fifth heat exchanger HX5 and the first heat exchanger HX1. As a result, the temperature reaches 893 K (reaction temperature) and 0.1 MPa (reaction pressure), and then steam reforming is performed in the steam reforming reactor R 1 while recovering heat at 620 ° C. from an external heat source. The hydrogen-rich medium flowing out from the steam reforming reactor R1 is heated by the first heater H1 to be in the state of 1052K and 0.1 MPa, and then the first pre-reaction medium in the first heat exchanger HX1. Heat is applied to 351K and 0.1 MPa. The hydrogen-rich medium flowing out from the first heat exchanger HX1 is in a state of 300 K and 0.1 MPa through the first gas-liquid separator F1, the first expander EX1, and the heat exchanger HX3.

  On the other hand, in the methanation circuit 2, the second pre-reaction medium supplied in the state of 300K and 0.1 MPa in the second supply flow path S21 is compressed by the second compressor C2 to be 377K, 0. After becoming 22 MPa, it will be in the state of 943K (reaction temperature) and 0.1 MPa (reaction pressure) by heating in the 2nd heat exchanger HX2. Thereafter, methanation is performed while generating heat in the methanation reactor R2. The methane-rich medium flowing out from the methanation reactor R2 is heated to a state of 1011.5K and 0.22 MPa by the second heater H2, and then before the second reaction in the second heat exchanger HX2. By applying heat to the medium, the state becomes 387K, 0.22 MPa. The methane-rich medium flowing out from the second heat exchanger HX2 is in a state of 300 K and 0.1 MPa through the fifth heat exchanger HX5, the second gas-liquid separator F2, the second expander EX2, and the heat exchanger HX6. .

  In this embodiment, the energy required to be input is 32.9 kW per system when the heat insulation efficiency of the entire furnace is 80%. Therefore, the total amount of input heat required to set the furnace temperature to 943 K by the 14 systems is about 0.5 MW.

  Next, a comparative example will be described.

  In the comparative example, fuel is supplied into each radiant tube arranged in the surrounding portion 3 (heating furnace), and combustion heating is performed by a burner. In the comparative example, when realizing the furnace temperature (943K) similar to that in the embodiment, 10 burners are necessary for the first zone and the second zone (the amount of input heat is 440 kW), respectively, and the third zone and the fourth zone respectively. Six burners (input heat amount 330 kW) are required. In this case, the amount of heat input into the furnace is 1.5 MW.

  That is, in the embodiment, the required input heat amount is about one-third that of the comparative example.

  The results of the above examples and comparative examples are shown in Table 1.

  The system of the present embodiment may be applied only to a part of the surrounding part 3 instead of the entire surrounding part 3 (heating furnace). The effect in that case is as shown in Table 1.

DESCRIPTION OF SYMBOLS 1 Steam reforming circuit 2 Methanation circuit 3 Enclosing part 4 Control part C1 1st compressor C2 2nd compressor EX1 1st expander EX2 2nd expander F1 1st gas-liquid separator F2 2nd gas-liquid separator G1 1st power recovery machine G2 2nd power recovery machine H1 1st heater H2 2nd heater R1 Steam reforming reactor R2 Methanation reactor S11 1st supply flow path S12 1st recovery flow path S21 2nd supply flow path S22 2nd collection flow path V1 1st on-off valve V2 2nd on-off valve

Claims (6)

A steam reforming circuit for steam reforming;
A methanation circuit for performing a methanation reaction,
The steam reforming circuit is
A steam reforming reactor for performing steam reforming to produce a hydrogen-rich medium mainly composed of hydrogen by reacting hydrocarbons with steam;
A first heater for heating the hydrogen-rich medium by supplying heat from the outside to the hydrogen-rich medium flowing out of the steam reforming reactor;
Before the first reaction, the hydrogen-rich medium flowing out from the first heater and the first pre-reaction medium containing hydrocarbons and steam and before flowing into the steam reforming reactor are subjected to heat exchange. A first heat exchanger for heating the medium,
The methanation circuit
A methanation reactor that performs methanation to produce a methane-rich medium mainly composed of methane by reacting hydrogen with at least one of carbon monoxide and carbon dioxide;
A second heater for heating the methane-rich medium by supplying heat from the outside to the methane-rich medium flowing out of the methanation reactor;
Heat exchange between the methane-rich medium flowing out from the second heater and the second pre-reaction medium containing at least one of carbon monoxide and carbon dioxide and hydrogen and flowing into the methanation reactor. A second heat exchanger for heating the second pre-reaction medium by
In the first heater, the temperature of the hydrogen-rich medium flowing out of the steam reforming reactor is the same as that of the first pre-reaction medium in the first heat exchanger. Heating the hydrogen-rich medium to a temperature that can be raised to the reaction temperature to be performed,
In the second heater, the temperature of the methane-rich medium flowing out from the methanation reactor is the same as that of the second pre-reaction medium in the second heat exchanger. A system comprising a steam reforming circuit and a methanation circuit for heating the methane-rich medium to a temperature that can be raised to a temperature. In a system comprising the steam reforming circuit and methanation circuit according to claim 1,
An enclosure having a shape surrounding the methanation reactor and the heat transfer space around the methanation reactor;
The methanation reactor is a system including a steam reforming circuit and a methanation circuit configured to be able to transfer reaction heat at the time of methanation in the methanation reactor to the heat transfer space. In a system comprising the steam reforming circuit and methanation circuit according to claim 2,
A steam reforming circuit and a methanation circuit, further comprising a control unit that adjusts the supply amount of the second pre-reaction medium to the methanation reactor so that the temperature of the heat transfer space falls within a target range. system. In a system comprising the steam reforming circuit and methanation circuit according to claim 3,
A second supply channel for supplying the second pre-reaction medium to the methanation reactor;
A second compressor provided in the second supply flow path;
A second on-off valve provided in the second supply flow path,
The controller is
When the temperature of the heat transfer space is smaller than the lower limit value of the target range and the flow rate of the second pre-reaction medium in the second supply flow path is smaller than a specified amount, the second compressor rotates. Increasing the number and increasing the opening of the second on-off valve, and increasing the heating amount of the methane-rich medium in the second heater,
When the temperature of the heat transfer space is smaller than the lower limit value of the target range and the flow rate of the second pre-reaction medium in the second supply flow path is larger than the specified amount, the second compressor Lowering the rotational speed and reducing the opening of the second on-off valve, and increasing the amount of heating of the methane-rich medium in the second heater,
When the temperature of the heat transfer space is larger than the upper limit value of the target range, the rotational speed of the second compressor is decreased, the opening of the second on-off valve is decreased, and the second heater A system comprising a steam reforming circuit and a methanation circuit for reducing the amount of heating of the methane-rich medium. In a system comprising the steam reforming circuit and methanation circuit according to any one of claims 1 to 4,
A first expander for expanding the hydrogen-rich medium flowing out of the first heat exchanger;
A system comprising a steam reforming circuit and a methanation circuit, further comprising a first power recovery machine connected to the first expander. In a system comprising the steam reforming circuit and methanation circuit according to any one of claims 1 to 5,
A second expander for expanding the methane-rich medium flowing out of the second heat exchanger;
A system comprising a steam reforming circuit and a methanation circuit, further comprising: a second power recovery unit connected to the second expander.

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