Synthesis gas production apparatus

Abstract

To provide a synthesis gas production apparatus which is relatively small-scale and has high conversion efficiency from exhaust gas to synthesis gas.SOLUTION: A synthesis gas production apparatus comprises: a first reactor incorporating a CO2 absorption and reduction type catalyst which absorbs carbon dioxide when supplying exhaust gas and discharges carbon monoxide when supplying hydrogen in a state of absorbing carbon dioxide; a second reactor incorporating a nonstoichiometric metal oxide that is reduced upon supply of hydrogen and oxidized upon supply of carbon dioxide and water in the reduced state to form carbon monoxide and hydrogen; a connection flow path which connects the first reactor and the second reactor; and a control unit which controls the synthesis gas production apparatus. The control unit alternately executes an absorption and reduction step of absorbing carbon dioxide by the CO2 absorption and reduction type catalyst while reducing the nonstoichiometric metal oxide, and a supply and discharge step of supplying the gas at the time of supplying hydrogen containing carbon monoxide to the second reactor while discharging the synthesis gas from the second reactor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a synthesis gas production apparatus. [Background technology]

[0002] From the viewpoint of global warming countermeasures, it has been considered to synthesize chemical products such as methanol and hydrocarbons using carbon dioxide recovered from exhaust gas. Patent Document 1 discloses a waste treatment system that performs a gasification process to obtain a gas containing carbon dioxide and hydrogen and a residue from waste, and then performs a methanol production process to synthesize methanol from the gas containing carbon dioxide and hydrogen. Patent Document 2 discloses a carbon monoxide production device that generates a carbon monoxide-containing gas containing carbon monoxide from a raw material gas containing carbon dioxide and hydrogen by a reverse shift reaction. The carbon monoxide-containing gas is used to synthesize chemical products. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2012 / 017893 [Patent Document 2] Patent Publication No. 2022-171010 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the gasification process used in the waste treatment system of Patent Document 1 is generally carried out in a very high temperature range (for example, 800 to 1100°C), so a large-scale heat-resistant reactor is required. In addition, it is necessary to add an incineration process for incinerating the residue obtained in the gasification process and a process for converting a considerable amount of carbon dioxide generated by the incineration process into methanol, and the temperature ranges in which these processes can operate are often significantly different. Therefore, the entire system becomes complex and large-scale, and the efficiency of converting waste into gas in the gasification process and the efficiency of synthesizing methanol from the gas tend to decrease.

[0005] On the other hand, in Patent Document 2, the composite tower for generating the carbon monoxide-containing gas contains an adsorbent for adsorbing water vapor contained in the carbon monoxide-containing gas, and many components are required, such as a pressure reducing device for desorbing water from the adsorbent, so that the entire apparatus becomes complex and large-scale, and the conversion efficiency from the raw material gas to the carbon monoxide-containing gas tends to decrease. For this reason, there has been a demand for the development of an apparatus that is relatively small-scale and has a high conversion efficiency to gases used in the synthesis of chemical products.

[0006] The present invention has been made to solve at least some of the above-mentioned problems, and has an object to provide a synthesis gas production apparatus that is relatively small in scale and has high efficiency of converting exhaust gas into synthesis gas. [Means for solving the problem]

[0007] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following forms.

[0008] (1) According to one aspect of the present invention, there is provided a synthesis gas production apparatus for producing synthesis gas containing carbon monoxide and hydrogen, comprising a first reactor incorporating a CO2 absorption / reduction catalyst that absorbs carbon dioxide in exhaust gas containing carbon dioxide when the exhaust gas is supplied and releases carbon monoxide when hydrogen is supplied in a state in which carbon dioxide has been absorbed, a second reactor incorporating a non-stoichiometric metal oxide that is reduced when hydrogen is supplied and that is oxidized when carbon dioxide and water are supplied in a reduced state to reduce carbon dioxide and water to produce carbon monoxide and hydrogen, and a second reactor incorporating a non-stoichiometric metal oxide that is reduced when hydrogen is supplied and that is oxidized when carbon dioxide and water are supplied in a reduced state to produce carbon monoxide and hydrogen, and a first reactor and a second reactor the control unit alternately executes an absorption / reduction process in which the exhaust gas is supplied to the first reactor to cause the CO2 absorption / reduction catalyst to absorb carbon dioxide while supplying hydrogen to the second reactor to reduce the non-stoichiometric metal oxide; and a supply / delivery process in which hydrogen is supplied to the first reactor to supply a hydrogen supply gas containing carbon monoxide released from the CO2 absorption / reduction catalyst to the second reactor while supplying hydrogen to the first reactor to deliver the synthesis gas from the second reactor.

[0009] According to this configuration, the carbon dioxide absorbed from the exhaust gas by the CO2 absorption and reduction catalyst is used to produce synthesis gas used in the synthesis of chemical products such as methanol and hydrocarbons, so that the amount of carbon dioxide discharged into the outside air can be reduced while the synthesis gas can be produced. In addition, according to this configuration, the main components that determine the size of the apparatus are the two reactors (the first reactor and the second reactor), and since the first reactor and the second reactor can be suitably operated in the same temperature range, they can be arranged close to each other, so that the synthesis gas production apparatus can be made relatively small-scale. Furthermore, during the supply and delivery process, the carbon dioxide and water out of the carbon monoxide, carbon dioxide, hydrogen, and water contained in the hydrogen supply gas are converted into carbon monoxide and hydrogen in the second reactor, so that the synthesis gas can be produced from the exhaust gas with high conversion efficiency. Therefore, according to this configuration, it is possible to provide a synthesis gas production apparatus that is relatively small-scale and has high conversion efficiency from exhaust gas to synthesis gas while reducing the amount of carbon dioxide discharged into the outside air.

[0010] (2) In the synthesis gas production apparatus of the above aspect, the control unit may further execute a removal step of removing the exhaust gas remaining in the first reactor to the outside of the synthesis gas production apparatus by reducing the pressure and degassing the first reactor or by supplying an inert gas to the first reactor after performing the absorption / reduction step and before performing the supply / delivery step, and a supply step of supplying the hydrogen supply gas remaining in the first reactor to the second reactor by reducing the pressure and degassing the first reactor or by supplying an inert gas to the first reactor after performing the supply / delivery step and before performing the absorption / reduction step. According to this configuration, the exhaust gas containing oxygen can be removed from the first reactor by the removal process, and the hydrogen supply gas containing hydrogen can be removed from the first reactor by the supply process. Therefore, the possibility of an explosion caused by the coexistence of high concentrations of oxygen and hydrogen inside the first reactor can be prevented, and safety in the production of synthetic gas using the synthetic gas production apparatus can be improved.

[0011] (3) The synthesis gas production apparatus of the above aspect may further include a plurality of units including the first reactor, the second reactor, and the connecting flow path, each of the units being arranged in parallel, and the control unit may control each of the units to start the absorption / reduction step at different timings during production of the synthesis gas by the synthesis gas production apparatus, and may maintain a first state in which there is always at least one of the units performing the absorption / reduction step. In general, exhaust gas is continuously discharged from incinerators, heating furnaces, boilers, internal combustion engines, etc. According to this configuration, when the synthesis gas is produced by the synthesis gas production apparatus, there is always at least one unit performing the absorption and reduction step, so that the synthesis gas production apparatus can always receive the continuously discharged exhaust gas.

[0012] (4) In the synthesis gas production apparatus of the above aspect, when the synthesis gas is produced by the synthesis gas production apparatus, the control unit may maintain, in addition to the first state, a second state in which each of the units is controlled to start the supply and delivery process at different timings, and there is always at least one of the units performing the supply and delivery process. In a synthesis gas production system connected to a chemical synthesis apparatus that synthesizes chemical products, it is necessary to continuously supply synthesis gas to the chemical synthesis apparatus in order to stably operate the chemical synthesis apparatus. With this configuration, when the synthesis gas is produced by the synthesis gas production system, there is always at least one unit that is performing the supply and delivery process, so that synthesis gas can be continuously supplied to the chemical synthesis apparatus.

[0013] (5) The synthesis gas production apparatus of the above embodiment may further include a concentration measuring unit that measures a molar amount of carbon monoxide and a molar amount of carbon dioxide contained in the gas when hydrogen is supplied, and the control unit may estimate a total molar amount of carbon monoxide contained in the synthesis gas discharged from the second reactor during the supply and delivery step based on values ​​measured by the concentration measuring unit, and adjust the amount of hydrogen supplied to the first reactor so that a molar ratio of the total molar amount of hydrogen supplied to the first reactor to the estimated total molar amount of carbon monoxide is within a range of 1.0 or more and 3.0 or less. To synthesize chemical products such as methanol and hydrocarbons from the synthesis gas, the H2 / CO molar ratio in the synthesis gas is preferably about 2. According to this configuration, the H2 / CO molar ratio in the synthesis gas produced by adjusting the amount of hydrogen supplied to the first reactor can be adjusted to a desired value within a generally effective range of 1.0 or more and 3.0 or less, and therefore a synthesis gas suitable for synthesizing chemical products can be produced.

[0014] (6) The synthesis gas production apparatus of the above embodiment may further include at least one of a first heat exchanger that performs heat exchange between the exhaust gas supplied to the first reactor and then discharged during the absorption / reduction step, and hydrogen that is supplied to the second reactor, a second heat exchanger that performs heat exchange between the exhaust gas supplied to the first reactor and a water-containing gas delivered from the second reactor during the absorption / reduction step, and a third heat exchanger that performs heat exchange between the hydrogen supplied to the first reactor and the synthesis gas delivered from the second reactor during the supply / delivery step. In a state where the first reactor and the second reactor are warmed to operate appropriately, the exhaust gas supplied to the first reactor and then discharged, the gas containing water discharged from the second reactor, and the synthesis gas discharged from the second reactor have relatively high thermal energy. According to this configuration, at least one of the following can be performed: heating hydrogen supplied to the second reactor using the exhaust gas supplied to the first reactor and then discharged; heating the exhaust gas supplied to the first reactor using the gas containing water discharged from the second reactor; and heating hydrogen supplied to the first reactor using the synthesis gas discharged from the second reactor. As a result, the energy required to heat the gas supplied to the first reactor and the second reactor can be reduced, and the conversion efficiency from the exhaust gas to the synthesis gas can be improved.

[0015] The present invention can be realized in various forms, for example, in the form of a system including a synthetic gas production apparatus, a control method for the synthetic gas production apparatus and system, a computer program for causing these apparatus and systems to produce synthetic gas, a server device for distributing this computer program, and a non-transitory storage medium on which the computer program is stored. [Brief description of the drawings]

[0016] [Figure 1] 1 is an explanatory diagram illustrating the configuration of a synthesis gas production apparatus according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is an explanatory diagram showing a synthesis gas production apparatus performing an absorption reduction process. [Diagram 3] FIG. 1 is an explanatory diagram showing a synthesis gas production unit performing a supply delivery process. [Figure 4] FIG. 2 is an explanatory diagram showing a synthesis gas production apparatus performing a removal process. [Diagram 5] FIG. 1 is an explanatory diagram showing a synthesis gas production apparatus performing a supply process. [Figure 6]FIG. 2 is an explanatory diagram illustrating the configuration of a synthesis gas production apparatus according to a second embodiment of the present invention. [Figure 7] FIG. 1 is an explanatory diagram showing a synthesis gas production apparatus performing an absorption reduction process. [Figure 8] FIG. 1 is an explanatory diagram showing a synthesis gas production unit performing a supply delivery process. [Figure 9] FIG. 11 is an explanatory diagram illustrating the configuration of a synthesis gas production apparatus according to a third embodiment of the present invention. [Figure 10] FIG. 2 is an explanatory diagram showing switching between processes in each unit. [Figure 11] FIG. 2 is an explanatory diagram showing switching between each process in each of two units. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] First Embodiment 1 is an explanatory diagram illustrating the configuration of a synthesis gas production apparatus 1 according to a first embodiment of the present invention. The synthesis gas production apparatus 1 is an apparatus for producing synthesis gas containing carbon monoxide and hydrogen. The synthesis gas production apparatus 1 includes a control unit 5, a first reactor 10, a second reactor 20, an exhaust gas supply flow path La, a hydrogen supply flow path Lb, an exhaust gas discharge flow path Lc, a connection flow path Ld, a hydrogen supply flow path Le, and a delivery flow path Lf.

[0018] The control unit 5 is a computer including a ROM, a RAM, and a CPU, and controls the synthesis gas production apparatus 1. The exhaust gas supply flow path La is a flow path for supplying exhaust gas containing carbon dioxide to the first reactor 10 described below. An on-off valve Va provided in the piping defining the exhaust gas supply flow path La opens and closes the exhaust gas supply flow path La. The hydrogen supply flow path Lb is a flow path for supplying hydrogen to the first reactor 10. An on-off valve Vb provided in the piping defining the hydrogen supply flow path Lb opens and closes the hydrogen supply flow path Lb.

[0019] The first reactor 10 is equipped with a CO2 absorption / reduction catalyst. The CO2 absorption / reduction catalyst absorbs carbon dioxide in the exhaust gas when the exhaust gas is supplied, and releases carbon monoxide when hydrogen is supplied after absorbing carbon dioxide. The CO2 absorption / reduction catalyst is characterized by containing one or more metal oxides selected from aluminum oxide (Al2O3), cerium oxide (CeO2), zirconium oxide (ZrO2), titanium oxide (TiO2), silicon oxide (SiO2), yttrium oxide (Y2O3), and lanthanum oxide (La2O3), and one or more basic substances selected from alkali metals and alkaline earth metals. The CO2 absorption / reduction catalyst may also contain a transition metal such as platinum (Pt) or palladium (Pd).

[0020] The exhaust gas discharge flow path Lc is a flow path for discharging the exhaust gas supplied from the exhaust gas supply flow path La to the first reactor 10 to the outside of the synthesis gas production apparatus 1. A degassing pump Dc and an on-off valve Vc are provided in the piping defining the exhaust gas discharge flow path Lc. The degassing pump Dc is a vacuum pump for reducing the pressure inside the first reactor 10 and degassing it. The on-off valve Vc opens and closes the exhaust gas discharge flow path Lc.

[0021] The connection flow path Ld connects the first reactor 10 and the second reactor 20 described below. A degassing pump Dd, an on-off valve Vd, and a concentration measurement unit S are provided in the piping that defines the connection flow path Ld. The degassing pump Dd is a vacuum pump for reducing the pressure and degassing the inside of the first reactor 10, similar to the degassing pump Dc. The on-off valve Vd opens and closes the connection flow path Ld. The concentration measurement unit S measures the molar amount of carbon monoxide and the molar amount of carbon dioxide contained in the gas flowing through the connection flow path Ld. In the following description, the molar amount is used to mean the amount of substance (mol).

[0022] The second reactor 20 contains a non-stoichiometric metal oxide. The non-stoichiometric metal oxide is reduced when hydrogen is supplied, and is oxidized when carbon dioxide and water are supplied in a reduced state, reducing carbon dioxide and water to produce carbon monoxide and hydrogen. The non-stoichiometric metal oxide is characterized by containing one or more transition metal oxides selected from vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), molybdenum (Mo), indium (In), tin (Sn), cerium (Ce), praseodymium (Pr), tungsten (W), lead (Pb), and bismuth (Bi). The cations of these transition metals have a plurality of oxidation states. The non-stoichiometric metal oxide may also contain a composite metal oxide of these transition metals and one or more metals selected from magnesium (Mg), aluminum (Al), lanthanum (La), strontium (Sr), and barium (Ba).

[0023] The hydrogen supply flow path Le is a flow path for supplying hydrogen to the second reactor 20. An on-off valve Ve provided in the piping defining the hydrogen supply flow path Le opens and closes the hydrogen supply flow path Le. The delivery flow path Lf is a flow path for delivering the water-containing gas and synthesis gas produced in the second reactor 20 to the outside of the synthesis gas production apparatus 1. The production of water and synthesis gas in the second reactor 20 will be described later. An on-off valve Vf provided in the piping defining the delivery flow path Lf opens and closes the delivery flow path Lf.

[0024] FIG. 2 is an explanatory diagram showing the synthesis gas production apparatus 1 during the absorption / reduction process. The control unit 5 executes the absorption / reduction process as one of the processes for producing synthesis gas. In FIG. 2, the on-off valves filled in black indicate that they are closed, and the flow paths indicated by dashed lines indicate that no flow is allowed. The same applies to the portions filled in black and the portions indicated by dashed lines in the following FIGS. 3 to 5, 7, and 8. In FIG. 2, the on-off valves Vb and Vd are closed, and therefore no flow is allowed through the hydrogen supply flow path Lb and the connection flow path Ld.

[0025] In the absorption and reduction step, the control unit 5 causes the first reactor 10 to supply exhaust gas to absorb carbon dioxide in the CO2 absorption and reduction catalyst, while supplying hydrogen to the second reactor 20 to reduce non-stoichiometric metal oxides. In detail, in the absorption and reduction step, the control unit 5 opens the on-off valve Va to allow the exhaust gas supply passage La to flow, thereby causing the exhaust gas to be supplied to the first reactor 10, thereby causing the CO2 absorption and reduction catalyst built into the first reactor 10 to absorb carbon dioxide. When exhaust gas containing carbon dioxide is supplied to the CO2 absorption and reduction catalyst, carbon dioxide, which is an acidic substance, is absorbed by the CO2 absorption and reduction catalyst by binding with the basic substance of the CO2 absorption and reduction catalyst through a neutralization reaction. In addition, the control unit 5 opens the on-off valve Vc to allow the exhaust gas discharge passage Lc to flow in the absorption and reduction step, and thereby causes the exhaust gas supplied to the first reactor 10 to be discharged to the outside of the synthesis gas production apparatus 1 through the exhaust gas discharge passage Lc. The exhaust gas emitted at this time contains oxygen, water, and nitrogen that were not absorbed by the CO2 absorption and reduction catalyst.

[0026] On the other hand, in the absorption reduction step, the control unit 5 opens the on-off valve Ve to allow the hydrogen supply passage Le to flow, thereby supplying hydrogen to the second reactor 20, thereby reducing the non-stoichiometric metal oxide contained in the second reactor 20. x As shown in the following formula (1), non-stoichiometric metal oxides represented by the formula " are reduced by releasing oxygen as the valence of cation M decreases (cation M is reduced), and the released oxygen combines with hydrogen to produce water. MO x +δH2→MO x- δ+δH2O…(1) In addition, in the absorption / reduction step, the control unit 5 opens the on-off valve Vf to allow the gas to flow through the delivery passage Lf, and thus sends out the water-containing gas produced in the second reactor 20 to the outside of the synthesis gas production apparatus 1 through the delivery passage Lf. In other words, by going through the absorption / reduction step, carbon dioxide is absorbed by the CO2 absorption / reduction catalyst built in the first reactor 10, and the non-stoichiometric metal oxide built in the second reactor 20 is in a reduced state (MOx- δ).

[0027] Fig. 3 is an explanatory diagram showing the synthesis gas production apparatus 1 during the supply and delivery process. The control unit 5 executes the supply and delivery process as one of the processes for producing synthesis gas. In Fig. 3, the on-off valves Va, Vc, and Ve are closed, so that the exhaust gas supply flow path La, the exhaust gas discharge flow path Lc, and the hydrogen supply flow path Le cannot flow.

[0028] In the supply and delivery step, the control unit 5 supplies hydrogen to the first reactor 10, thereby supplying hydrogen supply gas containing carbon monoxide released from the CO2 absorption and reduction catalyst to the second reactor 20, while discharging synthesis gas from the second reactor 20. In detail, in the supply and delivery step, the control unit 5 opens the on-off valve Vb to allow hydrogen supply flow through the hydrogen supply passage Lb, thereby discharging carbon monoxide from the CO2 absorption and reduction catalyst. When hydrogen is supplied to the CO2 absorption and reduction catalyst in a state in which carbon dioxide has been absorbed, the carbon dioxide is converted to carbon monoxide by a reverse shift reaction represented by the following formula (2), and is released from the CO2 absorption and reduction catalyst. At this time, water is produced along with the conversion to carbon monoxide. CO2+H2→CO+H2O…(2) In the supply and delivery step, the control unit 5 opens the on-off valve Vd to allow the connection flow path Ld to flow, so that the hydrogen supply gas containing carbon monoxide released by the supply of hydrogen to the first reactor 10 is supplied to the second reactor 20. The hydrogen supply gas refers to the gas supplied from the first reactor 10 to the second reactor 20 through the connection flow path Ld when hydrogen is supplied to the first reactor 10, and contains unreacted carbon dioxide and hydrogen in addition to carbon monoxide and water synthesized by the reverse shift reaction. The reverse shift reaction in the first reactor 10 is subject to equilibrium constraints, so the hydrogen supply gas may contain unreacted carbon dioxide and hydrogen.

[0029] When the hydrogen supply gas is supplied to the second reactor 20, the non-stoichiometric metal oxide contained in the second reactor 20 is oxidized. Specifically, as represented by the following formulas (3) and (4), the non-stoichiometric metal oxide converts carbon dioxide and water in the hydrogen supply gas into carbon monoxide and hydrogen as the valence of the cation M increases (as the cation M is oxidized). MO x- δ + δH2O → MO x +δH2…(3) MO x- δ+δCO2→MO x +δCO…(4) That is, among the carbon monoxide, water, carbon dioxide, and hydrogen contained in the hydrogen supply gas, the carbon dioxide and water are converted to carbon monoxide and hydrogen, and thus, by supplying the hydrogen supply gas to the second reactor 20, a synthesis gas mainly composed of carbon monoxide and hydrogen is generated from the hydrogen supply gas. The reactions of the above formulas (3) and (4) in the second reactor 20 are not subject to equilibrium constraints, and carbon monoxide and hydrogen are obtained with a high conversion rate. In the supply and delivery step, the control unit 5 opens the on-off valve Vf to allow the delivery flow path Lf to flow, and therefore delivers the synthesis gas generated in the second reactor 20 to the outside of the synthesis gas production apparatus 1 via the delivery flow path Lf.

[0030] The control unit 5 causes the synthesis gas production apparatus 1 to produce synthesis gas by alternately executing the absorption reduction step described with reference to FIG. 2 and the supply delivery step described with reference to FIG. 3. The preferred temperature range for the absorption of carbon dioxide into the CO2 absorption reduction catalyst in the first reactor 10 and the release of carbon dioxide from the catalyst is in the range of 350°C to 600°C. On the other hand, the preferred temperature range for the reduction and oxidation of non-stoichiometric metal oxides in the second reactor 20 is in the range of 450°C to 850°C. Therefore, the preferred temperature range for both the first reactor 10 and the second reactor 20 is in the range of 450°C to 600°C. For this reason, in this embodiment, the first reactor 10 and the second reactor 20 are disposed close to each other, and the temperatures of the first reactor 10 and the second reactor 20 are adjusted to be in the range of 450°C to 600°C by a heater (not shown) or the like while the absorption reduction step and the supply delivery step are being performed.

[0031] Moreover, the control unit 5 executes a removing step and a supplying step, which will be described next, between the absorbing / reducing step and the supplying / delivering step, which are executed alternately.

[0032] Fig. 4 is an explanatory diagram showing the synthesis gas production apparatus 1 during the removal process. The control unit 5 performs the removal process after performing the absorption reduction process (Fig. 2) and before performing the supply delivery process (Fig. 3). The state shown in Fig. 4 is different from the state shown in Fig. 2 in that the on-off valve Va is closed and the exhaust gas supply flow path La cannot flow in addition to the hydrogen supply flow path Lb and the connection flow path Ld.

[0033] In the removal step, the control unit 5 controls the degassing pump Dc to reduce pressure and degas the inside of the first reactor 10, thereby removing the exhaust gas remaining in the first reactor 10 to the outside of the synthesis gas production apparatus 1. The removal step is a step aimed at removing oxygen contained in the exhaust gas remaining in the first reactor 10.

[0034] Fig. 5 is an explanatory diagram showing the synthesis gas production apparatus 1 during the supply process. The control unit 5 executes the supply process after executing the supply and delivery process (Fig. 3) and before executing the absorption and reduction process (Fig. 2). The state shown in Fig. 5 is a state in which the on-off valve Vb is closed compared to the state shown in Fig. 3, and the hydrogen supply flow path Lb is also blocked in addition to the exhaust gas supply flow path La, the exhaust gas discharge flow path Lc, and the hydrogen supply flow path Le.

[0035] In the supply step, the control unit 5 controls the degassing pump Dd to depressurize and degas the first reactor 10, thereby supplying the hydrogen supply gas remaining in the first reactor 10 into the second reactor 20. The supply step is a step aimed at removing hydrogen contained in the hydrogen supply gas remaining in the first reactor 10. Between the absorption / reduction step and the supply / delivery step, which are alternately performed, the control unit 5 performs the removal step described with reference to FIG. 4 and the supply step described with reference to FIG. 5, thereby preventing high concentrations of oxygen and hydrogen from coexisting inside the first reactor 10.

[0036] In order to synthesize chemical products such as methanol and hydrocarbons from a synthesis gas, it is preferable that the H2 / CO molar ratio in the synthesis gas is about 2, as represented by the following formulas (5) and (6). CO+2H2→CH3OH…(5) nCO+(2n+1)H2→C n H 2n+2 +nH2O…(6) The molar amount of hydrogen in the synthesis gas obtained in the supply / delivery process is the same as the total molar amount of the molar amount of hydrogen contained in the hydrogen supply gas and the molar amount of hydrogen (H2 in H2O) constituting the water contained in the hydrogen supply gas. This total molar amount is also the same as the molar amount of hydrogen supplied to the first reactor 10 in the supply / delivery process. Therefore, the molar amount of hydrogen in the synthesis gas obtained in the supply / delivery process is determined according to the supply flow rate and supply time of hydrogen to the first reactor 10. On the other hand, the molar amount of carbon monoxide in the synthesis gas obtained in the supply / delivery process is the same as the total molar amount of the carbon monoxide contained in the hydrogen supply gas and the molar amount of carbon dioxide contained in the hydrogen supply gas (because the carbon dioxide contained in the hydrogen supply gas is converted to carbon monoxide in the supply / delivery process).

[0037] The concentration measuring unit S measures the molar amount of carbon monoxide and the molar amount of carbon dioxide contained in the hydrogen supply gas as the gas flowing through the connection flow path Ld. Then, the control unit 5 can adjust the H2 / CO molar ratio in the synthesis gas to a desired value in the range of 1.0 or more and 3.0 or less based on the value measured by the concentration measuring unit S. For example, in the case of the synthesis gas sent out from the second reactor 20 during one supply and delivery process, the control unit 5 adjusts the H2 / CO molar ratio in the synthesis gas in the following procedure. First, based on the value measured by the concentration measuring unit S (the concentration of carbon monoxide and the concentration of carbon dioxide contained in the hydrogen supply gas), the control unit 5 integrates the molar amount of carbon monoxide and the molar amount of carbon dioxide contained in the hydrogen supply gas supplied to the second reactor 20 from the start of one supply and delivery process to the present time, and calculates the integrated molar amount M1 of carbon monoxide and the integrated molar amount M2 of carbon dioxide. Next, the control unit 5 estimates the total molar amount by regarding the sum of the molar integrated amount M1 and the molar integrated amount M2 as the total molar amount of carbon monoxide contained in the synthesis gas discharged from the second reactor 20. Then, the control unit 5 adjusts the amount of hydrogen supplied to the first reactor 10 so that the molar ratio of the total molar amount of hydrogen supplied to the first reactor 10 to the estimated total molar amount of carbon monoxide is a value in the range of 1.0 or more and 3.0 or less. Specifically, while the supply and delivery process is being performed, the control unit 5 adjusts the amount of hydrogen supplied to the first reactor 10 by controlling the opening and closing degree and opening and closing time of the on-off valve Vb according to the total molar amount of carbon monoxide estimated in real time. As a result, the control unit 5 can adjust the H2 / CO molar ratio in the synthesis gas discharged from the second reactor 20 during one supply and delivery process to a desired value in the range of 1.0 or more and 3.0 or less.

[0038] In the supply and delivery process, immediately after the supply of hydrogen to the first reactor 10 through the hydrogen supply flow path Lb is started, all the supplied hydrogen is used in the reverse shift reaction (see the above formula (2)), and the H2 / CO molar ratio in the synthesis gas delivered from the second reactor 20 is approximately 1. However, as the carbon dioxide absorbed in the CO2 absorption and reduction catalyst gradually decreases due to the continued supply of hydrogen, the H2 / CO molar ratio in the synthesis gas delivered from the second reactor 20 gradually increases. Therefore, if the supply of hydrogen to the first reactor 10 through the hydrogen supply flow path Lb is stopped at the point in time when the H2 / CO molar ratio in the synthesis gas reaches a desired value in the range of 1.0 or more and 3.0 or less, the H2 / CO molar ratio in the synthesis gas delivered from the second reactor 20 can be matched to the desired value.

[0039] In the above example, the case of the synthesis gas discharged from the second reactor 20 during one supply / delivery step has been described, but in the case of the synthesis gas discharged from the second reactor 20 during multiple supply / delivery steps, the H2 / CO molar ratio in the synthesis gas discharged from the second reactor 20 during multiple supply / delivery steps can be adjusted to a desired value in the range of 1.0 or more and 3.0 or less. That is, the molar amount of carbon monoxide and the molar amount of carbon dioxide contained in the hydrogen supply gas supplied to the second reactor 20 from the start of the first supply / delivery step among the multiple target supply / delivery steps to the current time are integrated to calculate the molar integrated amount M1 and the molar integrated amount M2, and then the same steps as those in the case of the synthesis gas discharged from the second reactor 20 during one supply / delivery step are performed, whereby the H2 / CO molar ratio in the synthesis gas can be adjusted to a desired value in the range of 1.0 or more and 3.0 or less.

[0040] According to the synthesis gas production apparatus 1 of the first embodiment described above, the synthesis gas used for synthesizing chemical products such as methanol and hydrocarbons is produced using carbon dioxide absorbed from the exhaust gas by the CO2 absorption and reduction catalyst, so that the synthesis gas can be produced while reducing the amount of carbon dioxide discharged into the outside air. Furthermore, according to the synthesis gas production apparatus 1 of the first embodiment, the configuration that determines the size of the apparatus is mainly two reactors (the first reactor 10 and the second reactor 20), and since the first reactor 10 and the second reactor 20 can be suitably operated in the same temperature range (450°C to 600°C), they can be arranged close to each other, so that the synthesis gas production apparatus 1 can be a relatively small-scale apparatus. Furthermore, during the supply and delivery process, the carbon dioxide and water out of the carbon monoxide, carbon dioxide, hydrogen, and water contained in the hydrogen supply gas are converted into carbon monoxide and hydrogen in the second reactor 20, so that the synthesis gas can be produced from the exhaust gas with high conversion efficiency. Therefore, according to the synthesis gas production apparatus 1 of the first embodiment, it is possible to provide a synthesis gas production apparatus 1 that is relatively small in scale and has high efficiency in converting exhaust gas into synthesis gas, while reducing the amount of carbon dioxide discharged into the outside air.

[0041] Furthermore, in the synthesis gas production apparatus 1 of the first embodiment, the control unit 5 executes a removal step and a supply step between the absorption / reduction step and the supply / delivery step which are alternately executed. Therefore, the exhaust gas containing oxygen can be removed from the first reactor 10 by the removal step, and the hydrogen supply gas containing hydrogen can be removed from the first reactor 10 by the supply step. Therefore, the possibility of an explosion due to the coexistence of high concentrations of oxygen and hydrogen inside the first reactor 10 can be prevented, and therefore the safety in the production of synthesis gas using the synthesis gas production apparatus 1 can be improved.

[0042] In the synthesis gas production apparatus 1 of the first embodiment, the control unit 5 adjusts the amount of hydrogen supplied to the first reactor 10 so that the molar ratio of the total molar amount of hydrogen supplied to the first reactor 10 to the total molar amount of carbon monoxide estimated based on the value measured by the concentration measurement unit S is a value in the range of 1.0 or more and 3.0 or less. In order to synthesize chemical products such as methanol and hydrocarbons from the synthesis gas, it is preferable that the H2 / CO molar ratio in the synthesis gas is about 2. In this regard, according to the synthesis gas production apparatus 1 of the first embodiment, the H2 / CO molar ratio in the synthesis gas produced by adjusting the amount of hydrogen supplied to the first reactor 10 can be adjusted to a desired value in the range of 1.0 or more and 3.0 or less, which is generally effective, and therefore a synthesis gas suitable for synthesizing chemical products can be produced.

[0043] A non-patent document (Journal of CO2 Utilization, 2022, vol. 60, p. 102049. Integrated CO2 capture and selective conversion to syngas using transition-metal-free Na / Al2O3 dual-function material) discloses a technology for producing a synthesis gas by supplying exhaust gas to a reactor and then supplying hydrogen to the reactor. However, since the H2 / CO molar ratio in the synthesis gas obtained by the technology disclosed here was 2.8 even at the moment when it was at its smallest, this synthesis gas is not suitable for use as it is in the synthesis of chemical products. On the other hand, the synthesis gas produced by the synthesis gas production apparatus 1 of the first embodiment can have its H2 / CO molar ratio adjusted to a value that can be used as it is in the synthesis of chemical products.

[0044] <Second embodiment> FIG. 6 is an explanatory diagram illustrating the configuration of a synthesis gas production apparatus 1a according to a second embodiment of the present invention. The synthesis gas production apparatus 1a according to the second embodiment includes a first heat exchanger He1, a second heat exchanger He2, a third heat exchanger He3, and a delivery flow path Lg in addition to the synthesis gas production apparatus 1 according to the first embodiment (see FIG. 1, etc.). Although the degassing pump Dc, the degassing pump Dd, and the concentration measurement unit S are not shown in FIG. 6, these configurations are also included in the synthesis gas production apparatus 1a according to the second embodiment. As in the first embodiment, in this embodiment, the first reactor 10 and the second reactor 20 are disposed close to each other, and the temperatures of the first reactor 10 and the second reactor 20 are adjusted to be within a range of 450° C. to 600° C. by a heater (not shown) or the like during the absorption reduction step and the supply delivery step.

[0045] In the first embodiment, the delivery flow passage Lf is a flow passage for delivering the water-containing gas and the synthesis gas produced in the second reactor 20 to the outside of the synthesis gas production apparatus 1. On the other hand, in the second embodiment, in addition to the delivery flow passage Lf, the delivery flow passage Lg is provided, so that the delivery flow passage Lf serves as a flow passage for delivering the water-containing gas produced in the second reactor 20 to the outside of the synthesis gas production apparatus 1, and the delivery flow passage Lg serves as a flow passage for delivering the synthesis gas produced in the second reactor 20 to the outside of the synthesis gas production apparatus 1.

[0046] The first heat exchanger He1 crosses the exhaust gas discharge passage Lc and the hydrogen supply passage Le therein, and performs heat exchange between the exhaust gas flowing in the exhaust gas discharge passage Lc and the hydrogen flowing in the hydrogen supply passage Le. The second heat exchanger He2 crosses the exhaust gas supply passage La and the delivery passage Lf therein, and performs heat exchange between the exhaust gas flowing in the exhaust gas supply passage La and the gas containing water flowing in the delivery passage Lf. The third heat exchanger He3 crosses the hydrogen supply passage Lb and the delivery passage Lg therein, and performs heat exchange between the hydrogen flowing in the hydrogen supply passage Lb and the synthesis gas flowing in the delivery passage Lg.

[0047] FIG. 7 is an explanatory diagram showing the synthesis gas production apparatus 1a during the absorption reduction step. At this time, the exhaust gas supplied to the first reactor 10 through the exhaust gas supply passage La is heated by the first reactor 10, whose temperature is adjusted by a heater or the like, and then passes through the first heat exchanger He1 while flowing through the exhaust gas discharge passage Lc. Then, the exhaust gas passing through the first heat exchanger He1 after being heated heats the hydrogen passing through the first heat exchanger He1 while flowing through the hydrogen supply passage Le. That is, the first heat exchanger He1 performs heat exchange between the exhaust gas supplied to the first reactor 10 and then discharged during the absorption reduction step and the hydrogen supplied to the second reactor 20.

[0048] 7, the gas containing water generated by the reduction of the non-stoichiometric metal oxide using hydrogen supplied to the second reactor 20 through the hydrogen supply passage Le is heated by the second reactor 20 whose temperature is adjusted by a heater or the like, and then passes through the second heat exchanger He2 while flowing through the delivery passage Lf. The gas containing water that passes through the second heat exchanger He2 after being heated heats the exhaust gas that passes through the second heat exchanger He2 while flowing through the exhaust gas supply passage La. That is, the second heat exchanger He2 exchanges heat between the exhaust gas supplied to the first reactor 10 during the absorption reduction step and the gas containing water sent out from the second reactor 20.

[0049] FIG. 8 is an explanatory diagram showing the synthesis gas production apparatus 1a during the supply and delivery process. At this time, the hydrogen supply gas generated in the first reactor 10 by supplying hydrogen to the first reactor 10 through the hydrogen supply flow path Lb is heated by the first reactor 10, whose temperature is adjusted by a heater or the like, and then supplied to the second reactor 20. In the second reactor 20, the hydrogen supply gas is converted into synthesis gas mainly composed of carbon monoxide and hydrogen, and is further heated by the second reactor 20, whose temperature is adjusted by a heater or the like, and then passes through the third heat exchanger He3 while flowing through the delivery flow path Lg. The synthesis gas passing through the third heat exchanger He3 after being heated heats the hydrogen passing through the third heat exchanger He3 while flowing through the hydrogen supply flow path Lb. That is, the third heat exchanger He3 exchanges heat between the hydrogen supplied to the first reactor 10 during the supply and delivery process and the synthesis gas delivered from the second reactor 20.

[0050] In a state where the first reactor 10 and the second reactor 20 are warmed for suitable operation, the exhaust gas supplied to the first reactor 10 and then discharged, the gas containing water discharged from the second reactor 20, and the synthesis gas discharged from the second reactor 20 have relatively high thermal energy. The synthesis gas production apparatus 1a of the second embodiment is equipped with a first heat exchanger He1, a second heat exchanger He2, and a third heat exchanger He3. Therefore, according to the synthesis gas production apparatus 1a of the second embodiment, it is possible to heat the hydrogen supplied to the second reactor 20 using the exhaust gas supplied to the first reactor 10 and then discharged, heat the exhaust gas supplied to the first reactor 10 using the gas containing water discharged from the second reactor 20, and heat the hydrogen supplied to the first reactor 10 using the synthesis gas discharged from the second reactor 20. As a result, the energy required to heat the gas supplied to the first reactor 10 and the second reactor 20 can be reduced, and the efficiency of converting the exhaust gas into synthesis gas can be improved.

[0051] <Third embodiment> 9 is an explanatory diagram illustrating the configuration of a synthetic gas production apparatus 1b according to a third embodiment of the present invention. The synthetic gas production apparatus 1b of the third embodiment includes a plurality of units U1 to U3. Each of the units U1 to U3 includes first reactors 11 to 13, second reactors 21 to 23, and various flow paths La1 to La3, Lb1 to Lb3, Lc1 to Lc3, Ld1 to Ld3, Le1 to Le3, and Lf1 to Lf3 connected to these two reactors, similar to the synthetic gas production apparatus 1 of the first embodiment (see FIG. 1, etc.). In the synthetic gas production apparatus 1b of the third embodiment, each of the units U1 to U3 is arranged in parallel.

[0052] In the synthesis gas production apparatus 1b shown in FIG. 9, the exhaust gas supply flow path LA is a flow path for supplying exhaust gas to each of the first reactors 11-13. The parts of the exhaust gas supply flow path LA that are connected to each of the first reactors 11-13 correspond to the exhaust gas supply flow paths La1-La3. In addition, in the synthesis gas production apparatus 1b shown in FIG. 9, the hydrogen supply flow path LB is a flow path for supplying hydrogen to each of the first reactors 11-13 and each of the second reactors 21-23. The parts of the hydrogen supply flow path LB that are connected to each of the first reactors 11-13 correspond to the hydrogen supply flow paths Lb1-Lb3. In addition, the parts of the hydrogen supply flow path LB that are connected to each of the second reactors 21-23 correspond to the hydrogen supply flow paths Le1-Le3.

[0053] Among the configurations of the units U1 to U3, the first reactors 11 to 13 and the second reactors 21 to 23 are similar to the first reactor 10 and the second reactor 20 in the synthesis gas production apparatus 1 of the first embodiment. The configurations of the units U1 to U3, except for the first reactors 11 to 13 and the second reactors 21 to 23, are indicated by symbols obtained by adding numbers to the alphabetic symbols indicating the respective components of the synthesis gas production apparatus 1 of the first embodiment (for example, the configuration of the symbol obtained by adding a number to the exhaust gas supply passage La, which is the alphabetic symbol, is the exhaust gas supply passages La1 to La3). The configurations indicated by the symbols obtained by adding a number to the alphabetic symbols (for example, the exhaust gas supply passages La1 to La3) are similar to the configuration of the synthesis gas production apparatus 1 of the first embodiment indicated by the alphabetic symbols (for example, the exhaust gas supply passage La). That is, the synthesis gas production apparatus 1b corresponds to an apparatus in which three synthesis gas production apparatuses 1 are arranged in parallel.

[0054] FIG. 10 is an explanatory diagram showing the switching of each process in each of the units U1 to U3. The horizontal axis indicates the passage of time. In the third embodiment, the control unit 5 causes each of the units U1 to U3 to execute each process in the order of the absorption / reduction process, the removal process, the supply / delivery process, and the supply process. Furthermore, during the production of synthesis gas by the synthesis gas production apparatus 1b, the control unit 5 controls each of the units U1 to U3 to start the absorption / reduction process at different timings, and maintains a first state in which there is always at least one unit executing the absorption / reduction process. That is, as shown in FIG. 10, at any point in time during the elapsed time shown on the horizontal axis, the absorption / reduction process is executed by any of the units U1 to U3.

[0055] During the production of synthesis gas by the synthesis gas production apparatus 1b, the control unit 5 controls the units U1 to U3 to start the supply / delivery process at different times in addition to the first state described above, and maintains a second state in which there is always at least one unit performing the supply / delivery process. That is, as shown in Fig. 10, at any point in time during the elapsed time shown on the horizontal axis, the supply / delivery process is being performed by any of the units U1 to U3.

[0056] In general, exhaust gas is continuously discharged from incinerators, heating furnaces, boilers, internal combustion engines, etc. In this regard, according to the synthesis gas production apparatus 1b of the third embodiment, when the synthesis gas is produced by the synthesis gas production apparatus 1b, at least one of the units U1 to U3 is always executing the absorption reduction step (maintaining the first state), so that the synthesis gas production apparatus 1b can always receive the continuously discharged exhaust gas.

[0057] In a synthesis gas production apparatus connected to a chemical synthesis apparatus that synthesizes chemical products, it is necessary to continuously supply synthesis gas to the chemical synthesis apparatus in order to stably operate the chemical synthesis apparatus. In this regard, according to the synthesis gas production apparatus 1b of the third embodiment, when the synthesis gas is produced by the synthesis gas production apparatus 1b, at least one of the units U1 to U3 is always executing the supply / delivery process (maintaining the second state), so that synthesis gas can be continuously supplied to the chemical synthesis apparatus.

[0058] <Modifications of this embodiment> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit and scope of the invention. For example, the following modifications are also possible.

[0059] In the first embodiment described above, the synthetic gas production apparatus 1 removes the exhaust gas remaining in the first reactor 10 and the gas at the time of hydrogen supply to the outside of the synthetic gas production apparatus 1 by depressurizing and degassing the inside of the first reactor 10 with the degassing pump Dc or the degassing pump Dd in the removal step and the supply step, but this is not limited thereto. For example, the synthetic gas production apparatus may remove the exhaust gas remaining in the first reactor 10 and the gas at the time of hydrogen supply to the outside of the synthetic gas production apparatus by supplying an inert gas (nitrogen, argon, etc.) to the first reactor 10 in the removal step and the supply step. In such a case, the control unit 5 opens an opening / closing valve that opens and closes an inert gas supply flow path (a flow path for supplying an inert gas to the first reactor 10) to make the inert gas supply flow path circulatable, thereby supplying the inert gas to the first reactor 10.

[0060] In the second embodiment described above, the synthesis gas production apparatus 1a includes the first heat exchanger He1, the second heat exchanger He2, and the third heat exchanger He3, but is not limited thereto. For example, the synthesis gas production apparatus may include at least one of the first heat exchanger He1, the second heat exchanger He2, and the third heat exchanger He3, or may not include any of the heat exchangers. Of course, it is preferable to include all of the heat exchangers from the viewpoint of reducing the energy required to heat the gas supplied to the first reactor 10 and the second reactor 20 and improving the efficiency of conversion from exhaust gas to synthesis gas.

[0061] In the third embodiment described above, the synthesis gas production apparatus 1b includes three units U1 to U3, but is not limited to this. The synthesis gas production apparatus may include two units, or may include four or more units. Depending on the number of units included, there may always be two or more units performing the absorption / reduction step in the first state, or there may always be two or more units performing the supply / delivery step in the second state.

[0062] 11 is an explanatory diagram showing the switching of each process in each of the two units U4, U5 when the synthesis gas production apparatus is equipped with the two units U4, U5. When there is no need to continuously supply synthesis gas to the chemical synthesis apparatus and it is only necessary to receive the exhaust gas that is continuously discharged, the synthesis gas production apparatus can be provided with the two units U4, U5 as shown in FIG.

[0063] Although the present aspect has been described above based on the embodiment and modified examples, the above-mentioned embodiment of the aspect is intended to facilitate understanding of the present aspect and does not limit the present aspect. The present aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents are included in the present aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate.

[0064] The present invention can also be realized in the following forms. [Application example 1] A synthesis gas production apparatus for producing a synthesis gas containing carbon monoxide and hydrogen, A first reactor having a built-in CO2 absorption / reduction catalyst that absorbs carbon dioxide in exhaust gas when carbon dioxide-containing exhaust gas is supplied, and releases carbon monoxide when hydrogen is supplied after absorbing carbon dioxide; a second reactor containing a non-stoichiometric metal oxide that is reduced when hydrogen is supplied and that is oxidized when carbon dioxide and water are supplied in a reduced state, thereby reducing carbon dioxide and water to produce carbon monoxide and hydrogen; A connecting flow path connecting the first reactor and the second reactor; A control unit that controls the synthesis gas production apparatus, The control unit is an absorption / reduction step of supplying the exhaust gas to the first reactor to cause the CO2 absorption / reduction catalyst to absorb carbon dioxide, while supplying hydrogen to the second reactor to reduce the non-stoichiometric metal oxide; a supply / delivery step of supplying hydrogen to the first reactor, while supplying hydrogen-supply gas containing carbon monoxide released from the CO2 absorption / reduction catalyst to the second reactor, and delivering the synthesis gas from the second reactor. [Application example 2] The synthesis gas production apparatus according to Application Example 1, The control unit further a removing step of removing the exhaust gas remaining in the first reactor to the outside of the synthesis gas production apparatus by depressurizing and degassing the first reactor or by supplying an inert gas to the first reactor after the absorption / reduction step is performed and before the supply / delivery step is performed; and a supply step of depressurizing and degassing the first reactor or supplying an inert gas to the first reactor after the supply and delivery step is performed and before the absorption and reduction step is performed, thereby supplying the hydrogen supply gas remaining in the first reactor into the second reactor. [Application example 3] The synthesis gas production apparatus according to Application Example 1 or Application Example 2, further comprising: A plurality of units including the first reactor, the second reactor, and the connecting flow path, Each of the units is arranged in parallel, The control unit controls each of the units to start the absorption / reduction process at different timings during production of the synthesis gas by the synthesis gas production apparatus, and maintains a first state in which there is always at least one of the units performing the absorption / reduction process. [Application example 4] The synthesis gas production apparatus according to any one of Application Examples 1 to 3, The control unit, during the production of the synthesis gas by the synthesis gas production apparatus, maintains, in addition to the first state, a second state in which each of the units is controlled to start the supply and delivery process at different timings, and in which there is always at least one of the units performing the supply and delivery process. [Application example 5] The synthesis gas production apparatus according to any one of Application Examples 1 to 4, further comprising: a concentration measuring unit for measuring the molar amount of carbon monoxide and the molar amount of carbon dioxide contained in the hydrogen supply gas; the control unit estimates a total molar amount of carbon monoxide contained in the synthesis gas discharged from the second reactor during the supply and discharge step based on the value measured by the concentration measurement unit, and adjusts the amount of hydrogen supplied to the first reactor so that a molar ratio of the total molar amount of hydrogen supplied to the first reactor to the estimated total molar amount of carbon monoxide is a value in the range of 1.0 or more and 3.0 or less. [Application Example 6] The synthesis gas production apparatus according to any one of Application Examples 1 to 5, further comprising: a first heat exchanger that performs heat exchange between the exhaust gas that is supplied to the first reactor and then discharged during the absorption and reduction step and hydrogen that is supplied to the second reactor; a second heat exchanger that performs heat exchange between the exhaust gas supplied to the first reactor and a water-containing gas sent out from the second reactor during the absorption and reduction step; and a third heat exchanger that performs heat exchange between the hydrogen supplied to the first reactor and the synthesis gas delivered from the second reactor during the supply and delivery step. [Explanation of symbols]

[0065] 1, 1a, 1b...Synthetic gas production equipment 5. Control section 10~13…First reactor 20~23: Second reactor Dc, Dd…Degassing pump He1…1st heat exchanger He2…Second heat exchanger He3…Third heat exchanger LA…Exhaust gas supply passage LB: Hydrogen supply channel La…Exhaust gas supply passage Lb…Hydrogen supply channel Lc…Exhaust gas discharge flow path Ld…connection flow path Le: Hydrogen supply channel Lf…Outlet flow path Lg…Outlet flow path S...Concentration measuring section U1~U5…Unit Va, Vb, Vc, Vd, Ve, Vf...Shut-off valve

Claims

1. A synthesis gas production apparatus for producing a synthesis gas containing carbon monoxide and hydrogen, When exhaust gas containing carbon dioxide is supplied, the CO absorber absorbs the carbon dioxide in the exhaust gas, and when hydrogen is supplied after absorbing the carbon dioxide, the CO absorber releases carbon monoxide. 2 A first reactor having an absorption reduction catalyst built therein; a second reactor containing a non-stoichiometric metal oxide that is reduced when hydrogen is supplied and that is oxidized when carbon dioxide and water are supplied in a reduced state, thereby reducing carbon dioxide and water to produce carbon monoxide and hydrogen; A connecting flow path connecting the first reactor and the second reactor; A control unit that controls the synthesis gas production apparatus, The control unit is The exhaust gas is supplied to the first reactor to 2 an absorption / reduction step of reducing the non-stoichiometric metal oxide by supplying hydrogen to the second reactor while allowing an absorption / reduction catalyst to absorb carbon dioxide; The CO is generated by supplying hydrogen to the first reactor. 2 a supply / delivery step of delivering the synthesis gas from the second reactor while supplying hydrogen supply gas containing carbon monoxide released from an absorption / reduction catalyst to the second reactor.

2. The synthesis gas production apparatus according to claim 1, The control unit further includes: a removing step of removing the exhaust gas remaining in the first reactor to the outside of the synthesis gas production apparatus by depressurizing and degassing the first reactor or by supplying an inert gas to the first reactor after the absorption / reduction step is performed and before the supply / delivery step is performed; and a supply step of depressurizing and degassing the first reactor or supplying an inert gas to the first reactor after the supply and delivery step is performed and before the absorption and reduction step is performed, thereby supplying the hydrogen supply gas remaining in the first reactor into the second reactor.

3. The synthesis gas production apparatus according to claim 1, further comprising: A plurality of units including the first reactor, the second reactor, and the connecting flow path are provided, Each of the units is arranged in parallel, The control unit controls each of the units to start the absorption / reduction process at different timings during production of the synthesis gas by the synthesis gas production apparatus, and maintains a first state in which there is always at least one of the units performing the absorption / reduction process.

4. The synthesis gas production apparatus according to claim 3, The control unit, during the production of the synthesis gas by the synthesis gas production apparatus, maintains, in addition to the first state, a second state in which each of the units is controlled to start the supply and delivery process at different timings, and in which there is always at least one unit performing the supply and delivery process.

5. The synthesis gas production apparatus according to claim 1, further comprising: a concentration measuring unit for measuring the molar amount of carbon monoxide and the molar amount of carbon dioxide contained in the hydrogen supply gas; the control unit estimates a total molar amount of carbon monoxide contained in the synthesis gas discharged from the second reactor during the supply and delivery step based on the value measured by the concentration measurement unit, and adjusts the amount of hydrogen supplied to the first reactor so that a molar ratio of the total molar amount of hydrogen supplied to the first reactor to the estimated total molar amount of carbon monoxide is a value in the range of 1.0 or more and 3.0 or less.

6. The synthesis gas production apparatus according to any one of claims 1 to 4, further comprising: a first heat exchanger that performs heat exchange between the exhaust gas that is supplied to the first reactor and then discharged during the absorption / reduction step and hydrogen that is supplied to the second reactor; a second heat exchanger that performs heat exchange between the exhaust gas supplied to the first reactor and a water-containing gas sent out from the second reactor during the absorption and reduction step; and a third heat exchanger that performs heat exchange between the hydrogen supplied to the first reactor and the synthesis gas delivered from the second reactor during the supply and delivery step.

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