KR102251314B1 - System for producing carbon monoxide and hydrogen from carbon dioxide and steam through a redox process and the method thereof - Google Patents

Abstract

The present invention relates to a system and method for producing syngas from carbon dioxide using a reversible oxidation-reduction converting agent, and carbon dioxide (CO ₂ ) into an oxidation-reduction conversion reactor filled with a reversible oxidation-reduction converting agent in a reduced state, By supplying a source gas containing one or more of water vapor (H ₂ 0) and supplying heat generated through a plasma generating device, the reduced metal oxide is oxidized and carbon dioxide (CO ₂ ) and water vapor (H ₂ 0 ) To produce carbon monoxide (CO) and hydrogen (H ₂ ), supply an inert gas into an oxidation-reduction conversion reactor filled with an oxidized reversible oxidation-reduction converter, and use plasma to produce carbon monoxide (CO) and hydrogen (H 2 ). It relates to a system and method for producing carbon monoxide and hydrogen from carbon dioxide and water using a reversible oxidation-reduction converting agent such that the reversible oxidation-reduction converting agent is reduced.

Description

A system and method for producing carbon monoxide and hydrogen from carbon dioxide and water using a reversible oxidation-reduction converting agent

The present invention relates to a system and method for producing carbon monoxide and hydrogen from carbon dioxide and water using a reversible oxidation-reduction converting agent, and more particularly, making a reversible oxidation-reduction converting agent into an oxygen-deficient state through plasma. To produce carbon monoxide (CO), hydrogen (H ₂ ), etc. by contacting the oxygen-deficient reversible oxidation-reduction converting agent with _{a gas containing at least one of carbon dioxide (CO 2} ) and water vapor (H _{2 0).} It relates to a system and a method thereof.

In recent years, the demand for research and development of alternative energy due to global warming and depletion of fossil fuels is constantly increasing, and carbon monoxide is decomposed by using the thermochemical redox cycle as an alternative to solving practical environmental and energy problems. The technology of producing and hydrogen and producing hydrocarbon energy from them is attracting attention.

The thermochemical redox cycle refers to a process at a high temperature, and a technology that uses solar energy as such a high-temperature energy source is actively under research and development.

In general, the thermochemical redox cycle of solar heat uses two separate reduction/oxidation agents using metal oxides (hereinafter referred to as'reversible oxidation-reduction converters') that can reversibly generate and heal oxygen defects as a reaction medium. It happens in stages. Here, in the first stage of reversible oxidation, the reversible oxidation-reduction converter is reduced at high temperature by concentrated solar energy (typically> 1473 K), and the reversible redox converter reduced in the next stage is brought into contact with carbon dioxide and/or water vapor. Produces carbon monoxide and hydrogen. The resulting syngas mixture is converted to replaceable hydrocarbons (gasoline, diesel, kerosene, etc.) using industrially identified catalysts such as FiscHer-TropscH synthesis.

More specifically, it is based on the oxidation/reduction reaction of a reversible oxidation-reduction converter to generate carbon monoxide (CO) and hydrogen (H _{2 ) by decomposing carbon dioxide (CO 2} ) and water vapor (H _{2 0) that are currently used.} The two-stage thermochemical redox cycle is as follows.

Step 1 (reduction step): Using concentrated solar energy as a heat source, the reversible oxidation-reduction converting agent loses oxygen and becomes partially deficient in oxygen, and the removed oxygen is produced in the form of molecular oxygen. )

MO _ox → MO _red + 0.5 O ₂ (1)

_{Step 2 (Oxidation step): By supplying carbon dioxide (CO 2} ) and water vapor (H ₂ 0) to the reversible oxidation-reduction converting agent in the oxygen-deficient state produced in the first step, the reversible oxidation-reduction converting agent is carbon dioxide ( It is _{oxidized by obtaining oxygen of CO 2} ) and water vapor (H ₂ 0) to produce carbon monoxide (CO) and hydrogen (H ₂ ) (2a, 2b), and the reversible oxidation-reduction converting agent returns to its original state.

MO _red + H ₂ O → MO _ox + H ₂ (2a)

MO _red + CO ₂ → MO _ox + CO (2b)

The oxidation-reduction converting agent returned to its original state is reduced again through the process of the first step, and reoxidized in the second step.

The thermochemical redox cycle using the condensed solar energy as described above can achieve high solar energy conversion efficiency and has the advantage of using eco-friendly renewable energy, but it collects solar heat to supply the high temperature required for the thermochemical redox cycle. There was a problem that the consumption of space and cost was too great to build a facility.

According to the above circumstances, the present invention relates to a new system for producing carbon monoxide and hydrogen from carbon _{dioxide (CO 2} ) and water vapor (H ₂ 0) through a thermochemical redox cycle using plasma without using solar energy. I would like to present it.

In addition, the present invention solves the problem of power supply and demand that may occur by using floating power including surplus power, surplus power at night, and renewable energy generated by over-producing the power used when generating such plasma in a power plant as a power source. I want to.

The current power system is a centralized system in which supply and demand are matched in real time. When a power provider predicts demand and establishes a supply plan, the power plant generates electricity collectively and immediately provides it to consumers. For this reason, power companies are making a lot of effort to accurately predict the demand, turn the right number of generators in a timely manner, and produce the right amount of power, but it is difficult to predict the power demand, spare power for stable power supply, etc. Surplus power is always generated due to various factors.

In addition, in the case of new and renewable energy, it is impossible to predict power consumption and generate electricity accordingly, as in the power plant. In fact, the direction of the wind suddenly changes, or clouds frequently pass over the installed solar panels even in clear weather.

In this way, in the power system of power plants and renewable energy, the frequency fluctuates in order to return the fluctuated frequency caused by the mismatch between the power demand and the supply power to the standard frequency. Adjust power generation to respond. The standard frequency of Korea's power system is set at 60Hz. When the power demand increases and the supply power becomes insufficient, the frequency drops below 60Hz, so the power plant raises the output and adjusts the frequency.If the power demand decreases and the supply power remains, the power plant reduces the output frequency because the frequency exceeds 60Hz. Although the frequency has been adjusted through the follow-up operation method, in the case of the frequency follow-up operation method, operation costs are high and the generator efficiency is different for each power plant, so when adjusting the output, the power plant efficiency may deteriorate, resulting in a decrease in the actual supply capacity. There is a problem that the failure rate of power plant equipment increases.

The present invention is a method for solving such a problem, as a method for solving such a problem, the floating power generated due to the inconsistency between the demanded power and the supplied power, such as surplus power generated by excess production in a power plant, surplus power at night, and floating power including renewable energy. By using the plasma generator, it is possible to receive power at a lower cost compared to general power, and at the same time, solve the above problem caused by a mismatch between the power demand and the power supplied in the power plant.

Next, the prior art existing in the field to which the technology of the present invention belongs will be briefly described, and then the technical matters that the present invention intends to achieve differently compared to the prior art will be described.

Publication No. 10-2018-0004165 (published 2018-01-10) _{relates to a method for converting carbon dioxide (CO 2} ) into a synthesis gas, and more specifically, a solid-supported catalyst comprising Cu and Mn. Providing a reaction chamber comprising; Supplying a reaction mixture comprising H ₂ and CO _{2 to the reaction chamber;} There is synthesis gas technology relates to a process for the manufacture are described containing; and H ₂ and the step of contacting the H ₂ and CO ₂ with a catalyst at a reaction temperature of 600 ℃ excess to provide a product mixture containing CO. The prior art is a technology for producing carbon monoxide (CO) by reacting hydrogen and carbon dioxide (CO ₂ ) in the presence of a catalyst, and does not include a technology that generates carbon monoxide (CO) rather than using hydrogen, and uses plasma as a heat source required for the reaction. not.

In addition, Patent Publication No. 10-1768001 (Announcement on Aug. 08, 2017) relates to a hybrid solar-chemical cycle process using oxygen donating particles, and more specifically, to supply high-temperature heat to a reduction reactor through a solar concentrator, Hydrocarbon fuel and oxygen donating particles are supplied to the reduction reactor, and the hydrocarbon fuel is converted to synthesis gas by partial oxidation by the oxygen donating particles, and the oxygen donating particles are reduced and then the reduced oxygen donating particles are transferred to the oxidation reactor. Thus, a technique for generating _{hydrogen (H 2} ) by a reduction reaction by steam is described. The prior art registered patent publication 10-1768001 is a problem of emitting greenhouse gases such _{as carbon dioxide (CO 2} ) and nitrogen oxides because reducing gas is used to reduce oxygen donating particles (reversible oxidation-reduction converting agent in the present invention). In addition, there are problems such as space and cost constraints due to the use of the solar heat collection system.

In addition, Japanese Laid-Open Patent Publication JP 2003-027241 (announced on January 29, 2003) generates microwave plasma at low pressure using a raw material gas _{consisting of carbon dioxide (CO 2} ), hydrogen (H ₂ ) and/or water vapor (H _{2 0).} A technology related to a method of converting _{carbon dioxide (CO 2} ), which continuously takes out combustible gas including carbon monoxide (CO) to the outside of the reaction chamber, into a combustible gas after contacting a catalyst fixed and arranged in a reaction chamber equipped with a means. Is described. The Japanese Laid-Open Patent Publication JP 2003-027241 is _{a technology for converting carbon dioxide (CO 2} ) using plasma, but is different from the present invention using a reversible oxidation-reduction converter.

Unexamined Patent Publication 10-2018-0004165 (published 2018-01-10) Registered Patent Publication 10-1768001 (2017.08.08. Announcement) Japanese Published Patent Publication JP 2003-027241 (announced on January 29, 2003)

The present invention is to provide a system with higher efficiency in a system for producing carbon monoxide (CO) and hydrogen (H _{2 ) by taking oxygen from carbon dioxide (CO 2} ) and water vapor (H _{2 0), etc.} There is this.

In addition, the present invention is a system capable of ensuring efficient use of floating power by enabling the use of floating power such as surplus power generated by excess production in a power plant, surplus power at night, and irregularly generated renewable energy as a useful energy source. And it has its purpose to provide a method.

As a means for solving the above problem, a system for producing a product gas containing at least one of carbon monoxide and hydrogen from a raw material gas containing at least one of carbon dioxide and water vapor using a reversible oxidation-reduction converting agent, as an embodiment An oxidation-reduction conversion reactor having a space formed therein so that the reversible oxidation-reduction conversion agent can be filled; A plasma generator capable of generating plasma in the inner space of the oxidation-reduction conversion reactor; A gas inlet to supply at least one _{of an inert gas, carbon dioxide (CO 2} ), and water vapor (H ₂ 0) to the inner space of the oxidation-reduction conversion reactor; And a gas discharge unit configured to discharge a gas including at least one of carbon monoxide and hydrogen from the oxidation-reduction conversion reactor to the outside. It characterized in that it comprises a.

In addition, as an embodiment, the system uses the heat of the high-temperature exhaust gas discharged to the outside of the oxidation-reduction conversion reactor in the reduction process of the reversible oxidation-reduction conversion agent, and the inside of the oxidation-reduction conversion reactor in the oxidation process. It characterized in that it further comprises a; heat exchanger for heating the carbon dioxide (CO ₂ ) and/or water vapor (H _{2 0) supplied to.}

In addition, as an embodiment, in the reduction process of the reversible oxidation-reduction converting agent, an inert gas is supplied into the oxidation-reduction conversion reactor, and the lattice oxygen released while the reversible oxidation-reduction converting agent in the oxidation state is reduced is oxygen gas. In the oxidation process of the reversible oxidation-reduction conversion agent, a gas including at least one of _{carbon dioxide (CO 2} ) and water vapor (H _{2 0) is supplied into the oxidation-reduction conversion reactor, and the reduced state} As the reversible oxidation-reduction converter is oxidized, _{it takes oxygen from at least one of carbon dioxide (CO 2} ) and water vapor (H ₂ 0) to produce at least one of carbon monoxide (CO) and hydrogen (H ₂ ), and through the plasma generator It is characterized in that it supplies heat required for the reduction process and the oxidation process of the reversible oxidation-reduction converter.

In addition, as an embodiment, the plasma generating device is driven by flowing power, and the floating power includes surplus power generated by excess production in a power plant, surplus power at night, and renewable energy.

In addition, as an embodiment, the reversible oxidation-reduction converter is a metal oxide having a fluorspar-type structure; Metal oxides having a spinel structure; Oxides having a perovskite structure represented by the general formula ABO ₃ (A and B are metal elements); Oxides having a brown miralite structure represented by the general formula A ₂ B ₂ O _{5 (A and B are metal elements);} It is characterized in that at least one selected from AlOx, MnOx, FeOx, CoOx, NiOx, CrOx, BiOx, GaOx, BOx, LaOx, and CeOx is used.

In addition, as an embodiment, the oxidation-reduction conversion reactor is provided in at least one or more, and each oxidation-reduction conversion reactor is characterized in that both a reduction process and an oxidation process of the reversible oxidation-reduction conversion agent are performed.

In addition, as an embodiment, the oxidation-reduction conversion reactor is provided in at least two or more, and the reduction process and the oxidation process of the reversible oxidation-reduction conversion agent are respectively performed in separate oxidation-reduction conversion reactors.

On the other hand, the method of producing a product gas containing at least one of carbon monoxide and hydrogen from a raw material gas containing at least one of carbon dioxide and water vapor using the reversible oxidation-reduction converter of the present invention is an embodiment, (1) internal An inert gas is supplied into an oxidation-reduction conversion reactor in which a reversible oxidation-reduction converter in an oxidized state is filled in the space, and thermal energy is supplied using plasma to reduce the reversible oxidation-reduction converter in the oxidized state, and the reversible A first step of allowing lattice oxygen released from the oxidation-reduction converter to be discharged as a gas; _{And (2) after the first step, at least one of carbon dioxide (CO 2} ) and water vapor (H ₂ 0) is supplied to a space filled with a reversible oxidation-reduction converter in a reduced state, so that the reversible oxidation-reduction converter is oxidized. And a second step of producing at least one of carbon monoxide (CO) and hydrogen (H ₂ ) by taking oxygen from at least one of carbon dioxide (CO ₂ ) and water vapor (H _{2 0).}

In addition, as an embodiment, the method uses the high temperature exhaust gas heat discharged to the outside of the oxidation-reduction conversion reactor in the first step to heat the feed supplied into the oxidation-reduction conversion reactor in the second step. It is characterized by that.

In addition, as an embodiment, the method is characterized in that the plasma generation in the first step is driven by one or more of flowing power among surplus power generated by excess production in a power plant, surplus power at night, and renewable energy.

In addition, as an embodiment, the temperature of the reduction step of the reversible oxidation-reduction converter is 1000 ℃ ~ 2000 ℃, the temperature of the oxidation step of the reversible oxidation-reduction converter is 500 ℃ ~ 1400 ℃ characterized in that do.

In addition, as an embodiment, the method is a synthesis gas containing _{carbon monoxide (CO) and hydrogen (H 2} ) produced in the oxidation step of the reversible oxidation-reduction converter using a FiscHer-TropscH reaction. It characterized in that it further comprises a; fuel production step of producing a hydrocarbon fuel from.

The present invention uses a redox process to _{take oxygen from carbon dioxide (CO 2} ) and water (H ₂ 0) to produce carbon monoxide (CO) and hydrogen (H ₂ ). By using it, installation space and cost can be saved, and a distributed, modular design that can apply an installation site to a required place is possible. In addition, by using plasma as a heat source, it is possible to shorten the time required for step-by-step switching of the redox process. Compared to the conventional external heating method, the removal efficiency of lattice oxygen is high, and the time required to remove lattice oxygen is greatly reduced, thereby reducing carbon dioxide. It is possible to increase the efficiency of the process of producing carbon monoxide (CO) and hydrogen (H _{2 ) from (CO 2} ) and water (H _{2 0).}

In addition, the present invention can be used as an energy source using excess power generated by excess production in a power plant, surplus power at night, and discontinuously produced renewable energy as an energy source, since it is possible to immediately drive when flowing power is generated, and applied to a power plant to reduce the amount of power generated. It has the effect of creating useful energy while reducing the cost of maintaining power quality and efficiency by reducing the flow current by controlling it, and has the effect of storing surplus power as chemical energy, and carbon resource conversion. There is an effect of creating a positive effect on the dissemination of technology.

_{1 illustrates a system for converting carbon dioxide (CO 2} ) and water vapor (H ₂ 0) using a reversible oxidation-reduction converter according to an embodiment of the present invention.
_{FIG. 2 shows a system for converting carbon dioxide (CO 2} ) and water vapor (H ₂ 0) using a reversible oxidation-reduction converting agent additionally including a heat exchanger according to an embodiment of the present invention.
3 is a diagram showing an oxidation-reduction conversion reactor in a system for converting _{carbon dioxide (CO 2} ) and water vapor (H ₂ 0) using a reversible oxidation-reduction converter according to an embodiment of the present invention.
4 is a graph obtained by measuring the amount of oxygen generated in a ceria sample by external heating in a process of reducing a reversible oxidation-reduction converter using a thermogravimetric analyzer (TGA).
5 is a graph showing the amount of oxygen generated in a ceria sample by plasma during the reduction process of the reversible oxidation-reduction converting agent.

Hereinafter, a system according to the present invention and a preferred embodiment of the method thereof will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily implement the present invention.

In each drawing of the present invention, the size or dimensions of the structures are shown to be enlarged or reduced than in actuality for the sake of clarity of the present invention, and the known configurations have been omitted so as to reveal a characteristic configuration, so the drawings are not limited thereto. .

In describing the principle of the preferred embodiment of the present invention in detail, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

In addition, the embodiments described in the present specification and the configurations shown in the drawings are only the most preferred embodiment of the present invention, and do not represent all the technical spirit of the present invention. It should be understood that there may be equivalents and variations.

The present invention supplies heat required for oxidation and reduction reactions using a plasma generator, and in the oxidation process of the reversible oxidation-reduction converting agent, the reversible oxidation-reduction converting agent is carbon dioxide (CO ₂ ) and/or water vapor (H ₂ 0). It takes oxygen from and produces carbon monoxide (CO) and hydrogen (H ₂ ), and in the reversible oxidation-reduction conversion agent's reduction process, the reversible oxidation-reduction converter removes lattice oxygen from the oxygen-depleted state. It relates to a system for producing an oxidation-reduction converting agent.

The reversible oxidation-reduction converter has oxygen ion conductivity and includes both metal/nonmetal oxides capable of having reversible oxygen vacancies. The reversible redox converter _{reacts with carbon dioxide (CO 2} ) and/or water vapor (H ₂ 0) as described above to receive oxygen and oxidizes itself, and in the reduction process, oxygen in the lattice escapes due to high thermal energy. It is different from a catalyst because it directly participates in the reaction process, such as being reduced.

Non-limiting examples of such reversible oxidation-reduction converting agents include cerium oxide; Metal oxides having a fluorspar-like structure typified by stabilized zirconia and the like; Metal oxides having a spinel structure; Oxides having a perovskite structure represented by the general formula ABO ₃ (A and B are metal elements); Oxides having a brown miralite structure represented by the general formula A ₂ B ₂ O _{5 (A and B are metal elements);} At least one or more selected from AlOx, MnOx, FeOx, CoOx, NiOx, CrOx, BiOx, GaOx, BOx, LaOx, and CeOx may be used.

Further, in the present invention, the reversible oxidation-reduction converting agent in the oxidation state is MO _ox, and the reversible oxidation-reduction converting agent in the reduced state is expressed as _{MO red.} I.e. redox processes in the present invention is reversible oxidation as a reaction medium - a redox pair of reduced conversion claim: to use a _{(Redox pair MO ox / MO red} ).

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

As shown in Fig. 1, the system for producing syngas from carbon dioxide using the reversible oxidation-reduction converter of the present invention includes oxidation-reduction conversion reactors 110 and 110 ′, plasma generator 120, It is configured to include a gas inlet (130, 130'), gas discharge (140, 140') and a power supply (150).

The oxidation-reduction conversion reactors 110 and 110 ′ have an internal space formed therein, and a reversible oxidation-reduction converter is filled in the internal space.

The plasma generating device 120 is a device capable of generating plasma inside the oxidation-reduction conversion reactor.

In general, plasma is classified into high-temperature plasma (equilibrium plasma) and low-temperature plasma (non-equilibrium plasma), and high-temperature plasma is a plasma that induces a high temperature of 1000°C or higher. High temperature plasma is used because high temperature is required.

A high-temperature thermal plasma generating device (Plasma Torch, Plasmatron) using electric energy can be defined as a device that converts a large amount of thermal energy that can be used for melting and reduction of an object to be treated.

For the generation of high-temperature thermal plasma, sufficient energy must be supplied for gas ionization. Without limitation, this energy can be generated as an electric arc generated by two electrodes. When the gas is passed between the hot arcs, the transition to the gas plasma is possible. A device that generates plasma by this process is called an arc plasma generator or a direct-current plasma method, and is the most widely used method.

In addition, plasma generation is possible through a strong electric field, and there are external capacitive plasma using an annular electrode installed outside the discharge tube, and inductive plasma using a high-frequency electromagnetic field induced by a cylindrical induction coil. .

In addition, the gas inlets 130 and 130 ′ supply inert gas, carbon dioxide (CO ₂ ), and water vapor (H ₂ 0) to the inner space of the oxidation-reduction conversion reactor. _{The gas inlet may selectively supply an inert gas, carbon dioxide (CO 2} ), and water vapor (H ₂ 0) into the reactor through a gas inflow control device such as a valve.

In addition, the gas discharge units 140 and 140 ′ are configured to discharge the gas inside the oxidation-reduction conversion reactor to the outside.

In addition, the system for converting carbon dioxide using the reversible oxidation-reduction converting agent of the present invention includes the oxidation-reduction conversion reactors 110 and 110 ′, plasma generator 120 and gas inlets 130 and 130 ′. , In addition to the gas discharge units 140 and 140 ′, it may be configured to additionally include a heating device 121 and/or a control unit (not shown).

In addition, the power supply unit 150 is the oxidation-reduction conversion reactor (110, 110'), a plasma generator (120), a heating device (121), a gas inlet (130, 130'), a gas discharge portion (140). , 140′), and a control unit (not shown).

In the reduction process of the reversible oxidation-reduction converting agent, some of the lattice oxygen of the reversible oxidation-reduction converting agent is removed by transferring high temperature heat to the reversible oxidation-reduction converting agent using a high-temperature plasma, and the reversible oxidation -The reduction converter is converted into a state deficient in oxygen, making it easy to receive oxygen from the outside.

In the oxidation process of the reversible oxidation-reduction converter, by supplying a gas containing at least one of _{carbon dioxide (CO 2} ) and water vapor (H _{2 0) into the oxidation-reduction conversion reactor, the reversible oxidation of the oxygen-deficient state} -The reduction converter receives oxygen from one or more of carbon dioxide (CO ₂ ) and water vapor (H ₂ 0) to fill the deficient oxygen, and the carbon dioxide and water vapor are _{converted into carbon monoxide (CO) and hydrogen (H 2} ), respectively. .

More specifically, in the system using the reversible oxidation-reduction converter according to the present invention, some lattice oxygen is desorbed from the reversible oxidation-reduction converter by a thermochemical reaction by supplying heat generated through a plasma generating device. . The desorbed lattice oxygen is rapidly removed to finally form a reversible oxidation-reduction modifier in an oxygen-deficient state. At this time, the lattice oxygen is discharged to the outside of the conversion reactor together with an inert gas in the form of gaseous oxygen (first step: a process of reducing a reversible oxidation-reduction converting agent).

As described above, in the system of the present invention to partially remove oxygen from the reversible oxidation-reduction converter, only an inert gas is supplied without supplying a separate reduction reactant, and the inert gas is converted to plasma through a plasma generator. The method of reducing the reversible oxidation-reduction converting agent only by a thermochemical method is used by allowing it to come into contact with the reversible oxidation-reduction converting agent in the oxidized state.

As described above, since oxygen must be removed from the reversible oxidation-reduction converter only by a thermochemical method, high temperature heat is required in the reduction process of the reversible oxidation-reduction converter, and a temperature of at least 1000°C is required, and preferably Is 1200°C or higher, more preferably 1600°C or higher.

The inert gas may be one or a mixture of two or more selected from helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), nitrogen, etc. It can be used as an efficient plasma generator gas.

Thereafter, the oxygen-deficient reversible oxidation-reduction converter produced in the first step is in a state that is easy to accept oxygen, so that oxygen is _{removed from stable molecules such as carbon dioxide (CO 2} ) and water vapor (H ₂ 0) at a relatively low temperature. It becomes acceptable. Therefore, the temperature in the second step can be performed even at a temperature much lower than the temperature in the first step.

In the case of conventional heating such as conventional solar heat or heating furnace, heat energy is mainly transferred from the outside to heat not only the reversible oxidation-reduction converting agent, but also peripheral devices such as the conversion reactor supporting the reversible oxidation-reduction converting agent. Since it has to be done, a lot of energy required for heating is required, and the process time for heating is also lengthened, so there is a disadvantage that a lot of time is required for the reduction reaction.

However, when plasma is used as a heat source, only the reversible oxidation-reduction converting agent can be directly and selectively heated, so the energy efficiency is relatively high, and the heating rate is also quite fast, so the time required for the conversion of oxidation and reduction can be shortened. Therefore, there is an advantage in that process efficiency can be increased because it can effectively cope with an uncertain occurrence situation of flowing power.

When heating the reversible oxidation-reduction converting agent using the plasma, the heating rate is preferably 50°C to 1000°C per minute, preferably 100 to 500°C per minute.

In the second step, carbon monoxide (CO) and hydrogen (H ₂ ) are produced _{by contacting a gas containing one or more of carbon dioxide (CO 2} ) and (H ₂ 0) with the reversible oxidation-reduction converter in the reduced state ( Step 2: Oxidation process of reversible oxidation-reduction converting agent).

The heating in the second step may use the exhaust gas heat in the first step. To this end, the system of the present invention may additionally include a heat exchanger 160. While the inert gas including oxygen gas discharged to the outside in the first step is at a very high temperature, carbon dioxide (CO ₂ ) and water vapor (H ₂ 0), which are the supply gases in the second step, are required for the reaction at a low temperature. Since it must be heated to a temperature, the exhaust gas of the first step and the supply gas of the second step pass through the heat exchanger to exchange heat, thereby increasing the temperature of the supply gas of the second step.

The heat exchanger may be composed of at least one of a shell & tube heat exchanger, a double pipe type heat exchanger, a plate type heat exchanger, or a coil type heat exchanger. .

Since the required reaction temperature in the second step is much lower than that of the first step, if the gas flow rate in the second step and the first step is properly adjusted, the second step only needs to use the waste heat of the exhaust gas of the first step. Also, heat required for the reaction can be supplied, so that the supply of heat energy from the outside can be avoided.

However, when heat energy is insufficient only by the use of the waste heat, heat energy may be additionally supplied by external heating or plasma.

In the system using the reversible oxidation-reduction converting agent according to the invention, the temperature during the reduction process of the first step, the reversible oxidation-reduction converter, is set to 1000° C. to 2000° C., and the second step, the reversible oxidation-reduction conversion. The temperature during the oxidizing process of the agent is set at 500°C to 1400°C. Preferably, the temperature of the first step is set to 1400°C to 1800°C, and the temperature of the reversible oxidation-reduction converter is set to 900°C to 1400°C. If the temperature at the time of the reduction process is less than 1000° C., reduction is difficult to occur, and when the temperature exceeds 2000° C., the efficiency of thermal energy decreases. In addition, when the temperature during the oxidation process is 500°C or less or 1400°C or more, it may be difficult for the oxidation reaction to occur.

In addition, the system using plasma according to the present invention uses fluctuating power as an energy source as a power source of the plasma generating device.

The flowing power may be, for example, surplus power produced in excess of power demand in a power plant such as a thermal power plant or a nuclear power plant, or renewable energy in which supply is unstable, such as solar energy or wind energy. Preferably, the use of excess power produced in a thermal power plant is good because carbon dioxide (CO ₂ ), which is essentially generated in thermal power generation, can be directly used as a feedstock required for the reforming reaction.

In this way, by using the surplus power generated by over-producing in the power plant or the floating power including renewable energy whose generation amount and generation time are irregular, it is possible to save the process cost and to immediately drive when the floating power is generated. Renewable energy produced discontinuously can also be used as current power.

In addition, the system using the reversible oxidation-reduction converter according to the present invention, as shown in Figure 3, the reduction process and the oxidation process of the reversible oxidation-reduction converter is performed in one oxidation-reduction conversion reactor. 1 and 2, the reduction process and the oxidation process of the reversible oxidation-reduction conversion agent may be performed in separate oxidation-reduction conversion reactors, respectively. That is, the reduction process of the reversible oxidation-reduction conversion agent is performed in the first oxidation-reduction conversion reactor 110, and the oxidation process of the reversible oxidation-reduction conversion agent is the second oxidation-reduction conversion reactor 110 ′. It can also be done in a way.

When the reversible oxidation-reduction conversion agent reduction process and the oxidation process are performed in one oxidation-reduction conversion reactor, in the reversible oxidation-reduction conversion agent oxidation process, carbon dioxide (CO ₂ ) and water vapor (H) into the oxidation-reduction conversion reactor. ₂ A gas containing at least one of 0) is supplied, and in the reduction process of the reversible oxidation-reduction converter in an oxidized state, an inert gas is supplied into the oxidation-reduction conversion reactor.

In addition, when the reduction process and the oxidation process of the reversible oxidation-reduction conversion agent are performed in separate oxidation-reduction conversion reactors, respectively, the reversible oxidation-reduction conversion agent in a reduced state in the first oxidation-reduction conversion reactor 110 Is supplied to the second oxidation-reduction conversion reactor (110 ′), and a reversible oxidation-reduction conversion agent in an oxidation state in the second oxidation-reduction conversion reactor is supplied to the first oxidation-reduction conversion reactor, thereby oxidation-reduction. The converting agent may be moved, and a method of converting the supplied gas according to the oxidation and reduction states of the oxidation-reduction converting agent may be used.

On the other hand, the form of the oxidation-reduction conversion reactor of the present invention is a fixed bed, a fluidized bed or a moving bed, or an entrained flow bed in which a reversible oxidation-reduction converter is accompanied by a gas flow. ), etc.

In addition, the system using the reversible oxidation-reduction converter according to the present invention additionally includes a FiscHer-TropscH reactor, and is produced in the oxidation-reduction conversion reactor using the Fischer-Tropsch reactor. Hydrocarbon (gasoline, diesel, kerosene, etc.) fuel can also be produced from syngas.

Hereinafter, a reversible oxidation-reduction conversion system using plasma according to the present invention will be described in detail through experimental examples.

In describing the principle of the preferred embodiment of the present invention in detail, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

<Experimental Example 1> Conversion to an oxygen-deficient state by removing lattice oxygen from ceria

<Comparative Example 1-1>

As a control for the reduction experiment of ceria using plasma, an experiment of reduction of ceria using external heating was conducted. For this, a thermogravimetric analyzer (Setaram Instrumntation, SETSYS Evolution TGA) was used. First, the experiment was conducted without ceria in order to check whether oxygen was generated from other substances in the analyzer. Ar gas was supplied into the analyzer at a rate of 120 cc/min, and an oxygen meter (Jedith, ZR-5) was used to quantify the oxygen concentration. In the heating step, the temperature was raised in the same process as shown in FIG. 4. The temperature increase rate was increased to 1600°C at 10°C/min and maintained for 1 hour. After the introduction of Ar gas, oxygen in the analyzer chamber slowly decreased due to the introduction of Ar. After about 140 minutes, oxygen was not measured at all. After that, oxygen was not measured at all even after heating up to 1600°C and after heating. This confirmed that there was no oxygen generating source in the analyzer.

<Comparative Example 1-2>

114.9 mg of ceria powder was prepared in the analyzer of Comparative Example 1-1, and Ar (120 cc/min) was added in the same manner as in Comparative Example 1-1. As in Comparative Example 1-1, it was confirmed that oxygen was not measured in 140 minutes after flowing Ar. The heating step is as shown in FIG. 4 and the temperature was raised to 1600°C at a rate of 10°C/min and maintained for 1 hour. An oxygen meter (Jedis, ZR-5) was used to quantify oxygen discharged from ceria to the outside. As shown in FIG. 4, ^{it was confirmed that oxygen was measured from 240 minutes (1200 o} C) of the measurement standard, which is oxygen generated from ceria, and the amount of the generated is quantified and shown in Table 1. In Table 1, the time required for oxygen generation refers to the time until oxygen starts to be generated in ceria and no more lattice oxygen escapes. _{When ceria (CeO 2} ) used in the temperature experiment is reduced to the maximum (CeO ₂ => Ce ₂ O ₃ ), the mass of oxygen generated (theoretical oxygen generation mass) is 5.337 mg, but in Comparative Example 1-2 experiment, 0.3167 It is a level of 5.9% of the theoretical value in mg, and the time required to remove all of the oxygen was about 23.5 minutes.

[Table 1]

<Example 1>

A 4g cylinder-shaped ceria (42% porosity) was placed inside the plasma equipment experiment. An oxygen meter (Jedis, ZR-5) was used to quantify oxygen discharged from ceria to the outside. Before the plasma oxidation/reduction reaction, it was prepared so that oxygen was not measured by purging with Ar. After lowering the pressure to low pressure to generate the plasma, the plasma was generated to proceed with the reduction reaction of ceria, and the measured value of oxygen concentration from the start of plasma generation Is shown in FIG. 5. The amount of Ar supplied at this time is 24 L/min. Since the plasma equipment can raise the temperature to a high temperature of 1600℃ or higher for a short time (within 5 minutes), as shown in Fig. 5, the oxygen is measured in about 4 minutes since it is heated to the temperature at which the lattice oxygen of ceria is removed in a short time after plasma generation. Can be confirmed.

It was confirmed that the temperature of the chamber inside the plasma increased instantaneously, so that the temperature rising rate could not be maintained at a constant rate, but the temperature was increased to 1600°C within 5 minutes. The oxygen generation amount is shown in Table 2, and about 7.1% of oxygen was generated compared to the theoretical oxygen generation amount, and the oxygen generation duration was 0.53 minutes.

In contrast to Example 1 and Comparative Example 1-2, when plasma is used, the heating rate is much faster than when a general temperature increasing equipment (thermogravimetric analyzer) is used, so that the reversible oxidation-reduction converter removes lattice oxygen, thereby depleting oxygen. It can be seen that the time required for conversion to the state is much shorter, the degree of reduction of the oxidation-reduction converting agent is higher, and the time required for oxygen generation is also greatly reduced. As a result, it can be seen that when using plasma, the oxidation-reduction conversion reaction can be carried out more efficiently within a very short time compared to the case of using a conventional heating facility.

[Table 2]

<Experimental Example 2> Hydrogen production experiment through steam supply from oxygen-deficient ceria

<Comparative Example 2-1>

In order to check the possibility of thermal decomposition by the temperature of the steam, the temperature of the thermogravimetric analyzer (Setaram Instrumntation, SETSYS Evolution TGA) was maintained at 900℃ without ceria, and the temperature of steam and Ar was set to 900℃. Each was supplied at 50 cc/min. Gas chromatography (Youngrin, YL 6100) was used to quantify the amount of hydrogen generated. In the experiment, it was confirmed that hydrogen was not generated.

<Comparative Example 2-2>

Steam was supplied to ceria deficient in lattice oxygen produced under the conditions of Comparative Example 1-2 in Experimental Example 1 to quantify the amount of hydrogen generated. The temperature of steam and Ar was set to 900°C and supplied at 50 cc/min, respectively. In order to quantify the amount of hydrogen generated, gas chromatography (YL 6100, YL 6100) was used to obtain the results shown in Table 3, and it was confirmed that the ratio of produced hydrogen to depleted oxygen was 81%. The ratio of the produced hydrogen to the depleted oxygen was calculated using the theoretical value of the volume of hydrogen generated when all of the depleted oxygen of ceria is filled (theoretical hydrogen generation volume).

[Table 3]

2) Example 2

In Experimental Example 1, under the conditions of Example 1, steam was supplied to ceria deficient in lattice oxygen to quantify the amount of hydrogen generated. The temperature of steam and Ar was set to 900°C and supplied at 12 L/min, respectively. Gas chromatography (Youngrin, YL 6100) was used to quantify the amount of hydrogen generated, and the results shown in Table 4 were obtained. It was confirmed that the molar ratio of produced hydrogen to the amount of oxygen depleted was 85%.

When comparing Comparative Example 2-2 and Example 2, the hydrogen generation of Example 2 according to the present invention is higher, which is the degree of reduction of the oxidation-reduction converting agent reduced by using the plasma according to the present invention. It is presumed to be because it is higher and the water is more easily decomposed.

[Table 4]

< Experimental example 3> oxygen starvation Seria Carbon monoxide conversion experiment of carbon dioxide by

<Comparative Example 3-1>

In order to check the possibility of thermal decomposition by the temperature of carbon dioxide, without ceria The temperature of the thermogravimetric analyzer (Setaram Instrumntation, SETSYS Evolution TGA) was maintained at 900°C, and _{the temperatures of CO 2} and Ar were set at 900°C, respectively, and supplied at 50 cc/min. Gas chromatography (Youngrin, YL 6100) was used to quantify the amount of carbon monoxide generated. In the experiment, it was confirmed that no carbon monoxide was generated.

(2) Comparative Example 3-2

The amount of carbon monoxide generated by supplying carbon dioxide to ceria deficient in lattice oxygen under the conditions of Comparative Example 1-2 was quantified. The temperatures of carbon dioxide and Ar were set at 900° C. and supplied at 50 cc/min, respectively. In order to quantify the amount of carbon monoxide generated, gas chromatography (Youngrin Machinery Co., Ltd., YL 6100) was used, and the results are shown in Table 5. It was confirmed that the molar ratio of produced carbon monoxide to the amount of oxygen depleted was 89%. The ratio of the produced CO to the depleted oxygen was calculated using the theoretical value of the CO volume (theoretical CO generation volume) generated when all the depleted oxygen of the ceria is filled.

[Table 5]

2) Example 3

The amount of carbon monoxide generated by supplying carbon dioxide to ceria deficient in lattice oxygen under the conditions of Example 1 in Experimental Example 1 was quantified. The temperatures of carbon dioxide and Ar were set at 900° C. and supplied at 12 L/min, respectively. Gas chromatography (Youngrin, YL 6100) was used to quantify the amount of carbon monoxide generated. The results shown in Table 6 were obtained, and it was confirmed that the molar ratio of the produced carbon monoxide to the amount of deficient oxygen was at the level of 90%.

When comparing the Comparative Example 3-2 and Example 3, the carbon monoxide generation of Example 3 according to the present invention is higher, which is the degree of reduction of the oxidation-reduction converting agent reduced using the plasma according to the present invention. It is presumed to be because it is higher and better decomposes carbon monoxide.

[Table 6]

As described above, the present invention has been described with reference to the accompanying drawings, examples, and comparative examples, but this is only exemplary, and various modifications and equivalent other implementations from those of ordinary skill in the art pertaining to the art. You will understand that an example is possible. Therefore, the technical protection scope of the present invention should be determined by the following claims.

110, 110′: oxidation-reduction conversion reactor
120: plasma generating device
121: heating device
130, 130′: gas inlet
140, 140′: gas discharge unit
150: power supply
160: heat exchanger

Claims (11)

In a product gas production system containing carbon monoxide and/or hydrogen from a source gas containing carbon dioxide and/or water vapor,
An oxidation-reduction conversion reactor having a space formed therein so that the reversible oxidation-reduction conversion agent can be filled;
A plasma generator capable of generating plasma in the inner space of the oxidation-reduction conversion reactor;
A gas inlet for supplying one or more _{of an inert gas, carbon dioxide (CO 2} ), and water vapor (H ₂ 0) to the internal space of the oxidation-reduction conversion reactor; And
A gas discharge unit for discharging the gas including the syngas generated in the oxidation-reduction conversion reactor to the outside; Including,
The product gas production system supplies an inert gas into the oxidation-reduction conversion reactor in the reduction process of the reversible oxidation-reduction converting agent so that lattice oxygen escaped while the reversible oxidation-reduction converting agent is reduced is discharged as gas,
In the oxidation process of the reversible oxidation-reduction converting agent, a source gas containing carbon dioxide and/or water vapor is supplied to oxidize the reversible oxidation-reduction converting agent in a reduced state while taking oxygen from the source gas to produce carbon monoxide and/or hydrogen. Is configured to generate gas,
Carbon monoxide and/or hydrogen from a source gas including carbon dioxide and/or water vapor using a reversible oxidation-reduction converting agent, characterized in that it is configured to supply heat necessary for the reduction process of the reversible oxidation-reduction converting agent through the plasma generator. Production gas production system. The method of claim 1,
Heating the raw material gas supplied to the inside of the oxidation-reduction conversion reactor in the oxidation process by using the heat of the high-temperature exhaust gas discharged to the outside of the oxidation-reduction conversion reactor in the reduction process of the reversible oxidation-reduction conversion agent. A system for producing a product gas comprising carbon monoxide and/or hydrogen from a source gas including carbon dioxide and/or steam using a reversible oxidation-reduction converter, further comprising: a heat exchanger. The method according to claim 1 or 2,
Including carbon monoxide and/or hydrogen from a source gas including carbon dioxide and/or water vapor using a reversible oxidation-reduction converter, characterized in that heat energy is supplied to the oxidation process of the reversible oxidation-reduction converter using the plasma generator. The generated gas production system. The method according to claim 1 or 2,
The plasma generating device is driven by flowing power,
The flow power is carbon monoxide from raw material gas including carbon dioxide and/or water vapor using a reversible oxidation-reduction converter, characterized in that it includes surplus power generated by excess production in a power plant, surplus power at night, and renewable energy. A production gas production system containing hydrogen. The method according to claim 1 or 2,
The reversible oxidation-reduction converting agent may include a metal oxide having a fluorspar-like structure; Metal oxides having a spinel structure; Oxides having a perovskite structure represented by the general formula ABO ₃ (A and B are metal elements); Oxides having a brown miralite structure represented by the general formula A ₂ B ₂ O _{5 (A and B are metal elements);} AlOx, MnOx, FeOx, CoOx, NiOx, CrOx, BiOx, GaOx, BOx, LaOx, characterized by using at least one selected from CeOx, including carbon dioxide and/or water vapor using a reversible oxidation-reduction converter A production gas production system containing carbon monoxide and/or hydrogen from a source gas. The method according to claim 1 or 2,
The oxidation-reduction conversion reactor is provided with at least one or more,
Carbon monoxide and/or carbon monoxide from a source gas including carbon dioxide and/or water vapor using a reversible oxidation-reduction converter, characterized in that both the reduction process and the oxidation process of the reversible oxidation-reduction converter are performed in each oxidation-reduction conversion reactor. Or a production gas production system containing hydrogen. The method according to claim 1 or 2,
The oxidation-reduction conversion reactor is provided in at least two or more, and the reversible oxidation-reduction conversion agent is characterized in that the reduction process and the oxidation process of the reversible oxidation-reduction conversion agent are performed in separate oxidation-reduction conversion reactors. A product gas production system containing carbon monoxide and/or hydrogen from a source gas containing carbon dioxide and/or water vapor used. In the method for producing a product gas containing carbon monoxide and/or hydrogen from a source gas containing carbon dioxide and/or water vapor using a reversible oxidation-reduction converter,
(1) An inert gas is supplied into an oxidation-reduction conversion reactor filled with an oxidized-state reversible oxidation-reduction converter in the internal space, and plasma is generated to supply thermal energy to reduce the oxidized-state reversible oxidation-reduction converter. And a first step of allowing lattice oxygen to escape from the reversible oxidation-reduction converter to be discharged as a gas; And
(2) After the first step, a source gas including carbon dioxide and/or water vapor is supplied to a space filled with a reversible oxidation-reduction converter in a reduced state, and the carbon dioxide and/or water vapor is oxidized while the reversible oxidation-reduction converter is oxidized. A second step of producing a product gas containing carbon monoxide and/or hydrogen by depriving oxygen from a source gas including carbon monoxide from a source gas including carbon dioxide and/or water vapor using a reversible oxidation-reduction converting agent containing, and / Or a method for producing a product gas containing hydrogen. The method of claim 8,
Reversible oxidation-reduction, characterized in that heating the feed supplied to the inside of the oxidation-reduction conversion reactor of the second stage by using the heat of the high-temperature exhaust gas discharged to the outside of the oxidation-reduction conversion reactor in the first step. A method of producing a product gas containing carbon monoxide and/or hydrogen from a source gas containing carbon dioxide and/or water vapor using a converting agent. The method according to claim 8 or 9,
The generation of the plasma in the first step is performed by using a reversible oxidation-reduction converting agent, characterized in that it is driven by at least one flowing power among surplus power generated by excess production in a power plant, surplus power at night, and renewable energy. Or a method for producing a product gas containing carbon monoxide and/or hydrogen from a source gas containing steam. The method according to claim 8 or 9,
Reversible oxidation-reduction conversion, characterized in that the temperature of the reduction step of the reversible oxidation-reduction converter is 1000 ℃ ~ 2000 ℃, the temperature of the oxidation step of the reversible oxidation-reduction converter is 500 ℃ ~ 1400 ℃ A method of producing a product gas containing carbon monoxide and/or hydrogen from a source gas containing carbon dioxide and/or water vapor using an agent.

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