Carbon capture devices for power generation

Abstract

Provided is a novel carbon fixation apparatus for power generation exhibiting high power generation efficiency.　The present invention comprises a reaction chamber 30 for causing carbon dioxide to react with magnesium, a supply means 20 for supplying a pressurized, carbon dioxide-enriched introduction gas A3 to the reaction chamber 30, a pulse power wave irradiator 31 for irradiating the interior of the reaction chamber 30 with a pulse power wave to cause streamer discharge, a power generation means 40 for generating power using the energy of gas A4, A5 supplied from the reaction chamber 30 in response to reaction, and a discharge means 90 for discharging remaining gas A9 from the power generation means 40.

Description

[Technical Field]

[0001] The present invention relates to a carbon sequestration device for power generation. [Background technology]

[0002] Conventionally, carbon fixation technologies have been known to reduce carbon dioxide generated during the combustion of fossil fuels in thermal power generation, gas flaring, etc. Some of these technologies involve reacting carbon dioxide with metal oxides to fix carbon. There are also carbon fixation devices that use the reaction heat generated during this reaction to generate electricity, thereby improving energy efficiency (see, for example, Patent Document 1).

[0003] Patent Document 1 describes a carbon fixation device for power generation that includes a reaction chamber, a communication passage communicating with the upstream side of the reaction chamber, and a generator capable of generating electricity in response to the rotation of a steam turbine. An inlet gas containing carbon dioxide generated by coal combustion flows into the reaction chamber through the communication passage, and the temperature inside the reaction chamber is adjusted to 750°C with the gas mixed with calcium oxide. This promotes the reaction of carbon dioxide with calcium oxide in the reaction chamber to generate calcium carbonate (carbonation), thereby fixing carbon. The reaction heat generated by this reaction is recovered, and the recovered heat is used to generate steam, which drives a turbine, enabling the generator to generate electricity. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 11-192416 (pages 4 and 5, Figure 8) Summary of the Invention [Problem to be solved by the invention]

[0005] However, in a carbon fixation device for power generation such as that described in Patent Document 1, the temperature inside the reaction chamber needs to be kept at 780°C or lower in order to fix carbon through carbonation by reacting carbon dioxide with calcium oxide, making it difficult to improve power generation efficiency.

[0006] The present invention has been made in view of these problems, and has as its object to provide a new carbon fixation device for power generation that exhibits high power generation efficiency. [Means for solving the problem]

[0007] In order to solve the above problems, the carbon fixation device for power generation of the present invention comprises: The apparatus is characterized by comprising a reaction chamber in which carbon dioxide is reacted with magnesium, a supply means for supplying pressurized carbon dioxide-rich introduced gas to the reaction chamber, a pulsed power wave irradiator for irradiating the reaction chamber with a pulsed power wave to generate a streamer discharge, a power generation means for generating electricity using the energy of the gas supplied from the reaction chamber in response to the reaction, and a discharge means for discharging remaining gas from the power generation means. According to this feature, by irradiating a pressurized carbon dioxide-rich introduced gas with a pulsed power wave and generating a streamer discharge, it is possible to cause a reaction between magnesium and carbon dioxide even in a carbon dioxide-rich gas that substantially contains components other than carbon dioxide. As a result, at least magnesium oxide and carbon are produced, thereby achieving carbon fixation, and the reaction reaches a high temperature of 1000°C or higher, resulting in high power generation efficiency by the power generation means.

[0008] The gas introduced from the supply means to the reaction chamber is characterized in that the carbon dioxide concentration is 10 to 80 vol %. According to this feature, the range of heat generated during the reaction is approximately 1500°C to 2000°C, which allows for a wide range of choices for the structures that make up the reaction chamber and power generation means, and allows these structures to be simplified.

[0009] The supplying means is characterized by having a pulsed power wave irradiator that irradiates the introduced gas with a pulsed power wave before it is supplied to the reaction chamber. According to this feature, NO contained in the gas before being supplied to the reaction chamber x can be reduced, so NO x Therefore, the reaction efficiency of magnesium and carbon dioxide can be improved.

[0010] The system is characterized by having a separator disposed downstream of the reaction chamber and capable of separating carbon dioxide and carbon monoxide, and a circulation means for supplying the gas from which carbon monoxide has been separated by the separator to the supply means. According to this feature, the gas from which carbon monoxide has been separated can be supplied to the supply means, whereby carbon fixation can be carried out again in the reaction chamber, thereby reducing the amount of carbon dioxide contained in the remaining gas. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing a carbon fixation device for power generation in an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention discovered that irradiating a mixture of magnesium (Mg) and carbon dioxide (CO2) with pulsed power waves can directly react Mg and CO2, and this discovery led to a completely new method for achieving both carbon fixation and power generation. Furthermore, it was discovered that when Mg and CO2 are reacted in a CO2 concentration relatively higher than that of the atmosphere, CO2 does not react completely with Mg, and although some carbon monoxide (CO) is produced, the reaction temperature does not reach an ultra-high temperature of approximately 3000°C. For reference, when the CO2 concentration is high, for example, 95% or higher, CO2 reacts almost completely with Mg, producing magnesium oxide (MgO) and carbon (C), but no CO is produced, and the temperature reaches approximately 3000°C or higher.

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A carbon fixation device for power generation according to the present invention will be described below with reference to the following examples. [Example]

[0014] The carbon fixation device 10 for power generation of this embodiment is capable of carbon fixation and power generation using carbon dioxide-rich introduced gas A1 generated by burning fossil fuel in a combustion furnace 1 of a thermal power plant.

[0015] 1, the carbon fixation device 10 includes a reaction chamber 30 in which carbon dioxide (CO2) reacts with magnesium (Mg), a supply means 20 that compresses a CO2-rich introduced gas A1 and supplies it to the reaction chamber 30, a second pulsed power wave irradiator 31 that irradiates the reaction chamber 30 with a pulsed power wave, a power generation means 40 that generates electricity using the energy of gases A4 and A5 supplied from the reaction chamber 30, a separator 60 that is disposed downstream of the power generation means 40 and is capable of separating CO2 and carbon monoxide (CO), a circulation means 80 that supplies gas A8 containing CO2 from which CO has been separated by the separator 60 to the supply means 20, and a discharge means 90 that discharges residual gas A9 whose energy has been used for power generation by the power generation means 40. In the following description, the combustion furnace 1 side of the thermal power plant will be referred to as the upstream side, and a ninth communication passage 91 side of the discharge means 90, which will be described later, will be referred to as the downstream side.

[0016] First, the supply means 20 will be described. The supply means 20 is mainly composed of, in order from the upstream side, a first communication passage 21 connected to the downstream side of the combustion furnace 1, a first pulsed power wave irradiator 22 that irradiates the inside of the first communication passage 21 with a pulsed power wave, a cooler 23 disposed downstream of the first communication passage 21, a second communication passage 24 disposed downstream of the cooler 23, an axial flow compressor 25 connected downstream of the second communication passage 24, and a third communication passage 26 connected downstream of the compressor 25 and upstream of the reaction chamber 30.

[0017] The first communication passage 21 is connected not only to the combustion furnace 1 but also to a check valve 82 of a circulation means 80 described later, so that gas A8 can flow into the first communication passage 21 through the check valve 82.

[0018] The first pulsed power wave irradiator 22 is capable of generating a first pulse streamer discharge from a plug 22a located in the first communication passage 21 and upstream of the junction with a check valve 82 (described later). In this embodiment, the first pulsed power wave irradiator 22 is capable of repeatedly generating a high voltage with a half-width of 80 ns, and is operated with a charging voltage of 20 kV, a discharging current of 170 A, and a power supply at 5 pps (pulses per second), thereby irradiating the first pulsed power wave and generating a first pulsed streamer discharge. In this way, it is important to operate the first pulsed power wave with short pulses, high voltage, small current, and short cycles to prevent glow discharge or arc discharge.

[0019] The reaction chamber 30 is designed to be highly heat-resistant and pressure-resistant, allowing Mg powder to be introduced through an inlet (not shown). A plug 31a of a second pulsed power wave irradiator 31 is also located within the reaction chamber 30, enabling second pulse streamer discharge to occur within the reaction chamber 30. A turbine 42 of a gas turbine power generator 41 is located downstream within the reaction chamber 30. In this embodiment, the second pulsed power wave irradiator 31 is capable of repeatedly generating a high voltage with a half-width of 40 ns. The charge voltage is set to 100 kV, the discharge current to 170 A, and the power supply is operated at 10 pps to irradiate the second pulsed power wave and generate a second pulse streamer discharge. It is therefore important to operate the device with short pulses, high voltage, small current, and short cycles to prevent glow discharge or arc discharge.

[0020] The power generation means 40 includes, from the upstream side, a gas turbine power generation unit 41 capable of generating electricity using high-temperature, high-pressure gas A4 generated by the reaction of CO2 and Mg in the reaction chamber 30, a fourth communication passage 45 connected to the downstream side of the turbine 42 (reaction chamber 30) of the gas turbine power generation unit 41, and a steam turbine power generation unit 46 capable of generating electricity using high-temperature gas A5.

[0021] The gas turbine power generation system 41 is mainly composed of a turbine 42 that is rotated by the pressure of high-temperature, high-pressure gas A4, and a power generation system 43 that can generate electricity in response to the rotation of the turbine 42. The steam turbine power generation system 46 is mainly composed of a cooler 47 that cools high-temperature gas A5, a turbine 48 that is rotated by steam generated when the gas A5 is cooled by the cooler 47, and a generator 49 that can generate electricity in response to the rotation of the turbine 48.

[0022] The separator 60 is disposed downstream of a fifth communication passage 50 connected to the downstream side of the cooler 47 of the steam turbine power generator 46. Also connected downstream of the separator 60 are a sixth communication passage 70 into which gas A7, from which CO has been recovered from gas A6, flows, and an eighth communication passage 71 into which gas A10, which has a high CO concentration due to the recovered CO, flows. Also connected downstream of the eighth communication passage 71 is a storage tank 72.

[0023] The circulation means 80 is mainly composed of the sixth communication passage 70 described above, a three-way valve V connected to the downstream side of the sixth communication passage 70, a seventh communication passage 81 connected to one downstream side of the three-way valve V, and a check valve 82 connected to the downstream side of the seventh communication passage 81.

[0024] The discharge means 90 is mainly composed of the sixth communication passage 70 described above, the three-way valve V, and a ninth communication passage 91 that is connected to the other downstream side of the three-way valve V and communicates with the outside of the carbon fixation device 10. In Fig. 1, the valve of the three-way valve V to which the ninth communication passage 91 is connected is in a closed state.

[0025] Next, the operation will be described. The CO2-rich introduced gas A1 generated by burning fossil fuel in the combustion furnace 1 flows into the first communication passage 21. The introduced gas A1 has a CO2 concentration of approximately 55%, and in addition to CO2, it also contains nitrogen (N2), hydrogen (H2), oxygen (O2), water vapor (H2O), nitrogen oxides (NO2), and the like. x The temperature of the introduced gas A1 is about 300°C, and the flow rate per unit time is 0.1 × 10 -4 m 3 / s.

[0026] As shown by the arrows, the introduced gas A1 introduced into the first communication passage 21 is converted into H, O, HO, NO, and other gases contained in the introduced gas A1 by the non-thermal equilibrium plasma generated by the first pulse streamer discharge continuously irradiated from the plug 22a of the first pulse power wave irradiator 22. x , the reaction of NH3 and the like is promoted, and N2, O2, ammonium nitrate (NH4NO3), etc. are generated. x The concentration is reduced. The supply means 20 is provided with a recovery container (not shown) for recovering NH4NO3.

[0027] NO x The introduced gas A1, whose concentration has been reduced, is introduced into the cooler 23 and cooled, as shown by the arrow, to become gas A2 at approximately 30°C. After passing through the second communication passage 24, as shown by the arrow, the gas A2 is compressed by the compressor 25. The water or steam that flows through the cooler 23 and has been heated by the heat of the introduced gas A1 can also be used to generate power by the steam turbine power generation device 46.

[0028] As shown by the arrow, the pressure is approximately 2.0 MPa and the flow rate per unit time is 5.0 x 10 -5 m 3 Gas A3 compressed and pressurized at 1 / s passes through third communication passage 26 and flows into reaction chamber 30, into which Mg powder has been added. Within reaction chamber 30, a short-term second pulse streamer discharge occurs from plug 31a of second pulse power wave irradiator 31, generating non-thermal equilibrium plasma within reaction chamber 30. It was confirmed that this non-thermal plasma causes direct reaction between CO2 and Mg contained in gas A3, producing magnesium oxide (MgO), carbon (C), CO, etc. In other words, carbon fixation of CO2 occurs, and the CO2 concentration in gas A3 is reduced.

[0029] This reaction generated reaction heat, and the temperature inside the reaction chamber 30 rose from about 1500° C. to about 2000° C. Even after the second pulsed power wave irradiation was stopped, it was observed that CO2 and Mg continued to react with each other due to the flow of gas A3 into the reaction chamber 30.

[0030] In this way, when Mg and CO2 have not yet reacted, it is possible to cause a reaction between Mg and CO2 by using the second pulse streamer discharge as a trigger, and once the reaction between Mg and CO2 has started, the high-temperature reaction heat generated allows the reaction to continue continuously.

[0031] Furthermore, the reaction between CO2 and Mg causes the temperature of the gas A3 to rise rapidly, which causes the gas A3 to expand rapidly, turning it into high-temperature, high-pressure gas A4, which is ejected downstream.

[0032] As shown by the arrow, gas A4 attempts to flow from the downstream side of reaction chamber 30 into fourth communication passage 45. At this time, gas A4 rotates turbine 42 of gas turbine power generation device 41 disposed between reaction chamber 30 and fourth communication passage 45. As gas A4 passes through, turbine 42 is rotated, and power is generated by power generation device 43 of gas turbine power generation device 41.

[0033] The high-temperature gas A5 that has flowed into the fourth communication passage 45 flows into a cooler 47 of the steam turbine generator 46, where it is cooled to become gas A6 at approximately 100°C to 150°C. Steam generated by this cooling causes a turbine 48 of the steam turbine generator 46 to rotate, causing a generator 49 of the steam turbine generator 46 to generate electricity.

[0034] Gas A6 cooled by cooler 47 is led to separator 60 through fifth communication passage 50, as shown by the arrow. Separator 60 separates the CO contained in gas A6, separating it into gas A10 containing a high concentration of CO and gas A7, which is the remaining gas from which CO has been separated. Gas A10 containing a high concentration of CO is sealed in storage tank 72 through eighth communication passage 71, as shown by the arrow.

[0035] On the other hand, gas A7, which is the remaining gas from which CO has been separated, is discharged to the sixth communication passage 70, as indicated by the arrows. A concentration sensor (not shown) capable of measuring the CO2 concentration contained in gas A7 is provided in the sixth communication passage 70, and in the case of gas A8 having a constant CO2 concentration (10 vol% in this embodiment) or higher, the ninth communication passage 91 side of the three-way valve V is closed, and the sixth communication passage 70 and the seventh communication passage 81 side are open. As a result, gas A8 is discharged to the first communication passage 21 through the three-way valve V, the seventh communication passage 81, and the check valve 82, as indicated by the arrows, and the above-mentioned cycle is repeated together with the introduced gas A1.

[0036] Furthermore, in the case of residual gas A9 having a constant CO2 concentration (less than 10 vol% in this embodiment), the seventh communication passage 81 side of the three-way valve V is closed, and the sixth communication passage 70 and the ninth communication passage 91 side are open. As a result, the residual gas A9 is discharged to the outside through the three-way valve V and the ninth communication passage 91, as shown by the dotted arrows.

[0037] As described above, in the carbon fixation device 10 of this embodiment, by irradiating the pressurized carbon dioxide-rich introduced gas A3 with a pulsed power wave from the second pulsed power wave irradiator 31 and generating a second pulsed streamer discharge, it was possible to cause a reaction between magnesium and carbon dioxide even in the carbon dioxide-rich gas A3 that substantially contains components other than carbon dioxide. As a result, carbon fixation is achieved by producing at least magnesium oxide and carbon, and this reaction reaches a high temperature of 1000°C or higher, generating a high-temperature, high-pressure gas A4, thereby increasing the power generation efficiency of the power generation means 40.

[0038] Furthermore, when the carbon dioxide concentration of the introduced gas A1 introduced into the reaction chamber 30 is approximately 55%, the range of heat generated during the reaction between carbon dioxide and magnesium is approximately 1500°C to 2000°C. On the other hand, when the carbon dioxide concentration of the introduced gas is 90% or more, the range of heat generated during the reaction between carbon dioxide and magnesium is approximately 2500°C to approximately 3000°C or more. Therefore, the carbon fixation device 10 of this embodiment, which generates a relatively lower range of heat during the reaction, has a wider range of options for the structures that constitute the reaction chamber 30 and the power generation means 40, and the structures of these can be simplified.

[0039] In addition, the NO contained in the introduced gas A1 before being supplied to the reaction chamber 30 is reduced by the pulse streamer discharge irradiated from the first pulse power wave irradiator 22. x can be reduced, so NO x Therefore, the reaction efficiency of magnesium and carbon dioxide can be improved.

[0040] Furthermore, when comparing the case where the range of heat generated during the reaction in the reaction chamber is about 1500°C to about 2000°C, as in the carbon fixation apparatus 10 of this embodiment, with the case where the range of heat generated during the reaction in the reaction chamber is about 2500°C to about 3000°C or more, unlike this embodiment, the amount of carbon dioxide fixed by one reaction of carbon dioxide and magnesium is smaller in the carbon fixation apparatus 10 of this embodiment.However, the carbon fixation apparatus 10 of this embodiment has a separator 60 arranged downstream of the reaction chamber 30 and a circulation means 80 that supplies the carbon dioxide-containing gas A8 from which carbon monoxide has been separated by the separator 60 to the first communication passage 21, and by supplying the carbon dioxide-containing gas A8 again to the first communication passage 21, carbon fixation can be performed again in the reaction chamber 30, thereby reducing the carbon dioxide contained in the residual gas A9.

[0041] Furthermore, thermal power plants to which the carbon fixation device 10 of this embodiment is applied are often built along the coast because a cooling process using cooling water is essential for thermal power generation and a water source must be secured. Since seawater can be easily supplied to coastal facilities, it is possible to use seawater as a magnesium supply source. In other words, because magnesium can be easily supplied, the cost of carbon fixation can be reduced.

[0042] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0043] For example, in the above embodiment, the configuration is described as being applied to a thermal power plant, but it is not limited to this and can be applied to any facility that generates gas with a carbon dioxide concentration of 10 to 80 vol%.

[0044] Furthermore, although the pulse streamer discharge by the first pulse power wave irradiator 22 has been described as occurring within the first communication passage 21, it is not limited to this, and may also occur within the second communication passage 24 after cooling by the cooler 23, or within the third communication passage 26 after compression by the compressor 25, and is not limited as long as it is within the range up to introduction into the reaction chamber 30.

[0045] Furthermore, the compressor 25 has been described as being separate from the gas turbine power generation device 41, but this is not limited thereto, and the compressor 25 may be configured to compress the gas by utilizing the rotational force of the turbine 42 of the gas turbine power generation device 41, which is rotated by the gas A4.

[0046] In addition, although the configuration has been described in which a short-time second pulse streamer discharge is emitted as a trigger for causing a reaction between Mg and CO2, the present invention is not limited to this, and a configuration may also be adopted in which a temperature sensor is placed in the reaction chamber 30 and a second pulse streamer discharge is emitted each time the temperature measured by the temperature sensor drops to 1500° C. or less. Furthermore, a configuration may also be adopted in which a second pulse streamer discharge is continuously emitted over the period during which Mg and CO2 are continuously reacted with each other. [Explanation of symbols]

[0047] 10 Carbon Fixation Device 20 Means of supply 22 First pulsed power wave irradiator 30 Reaction Chamber 31 Second pulsed power wave irradiator 40 Means of power generation 60 Separator 80 Circulation means 90 Means of discharge A1 Introduced gas A3 Pressurized carbon dioxide-rich inlet gas A9 Residual gas

Claims

1. a reaction chamber for reacting carbon dioxide with magnesium, a supply means for supplying a pressurized carbon dioxide-rich gas to the reaction chamber, and a pulsed power wave irradiator for irradiating a pulsed power wave into the reaction chamber to generate a streamer discharge; The carbon fixation apparatus is characterized in that the supplying means has a pulsed power wave irradiator that irradiates the introduced gas with a pulsed power wave before the introduced gas is supplied to the reaction chamber.

2. 2. The carbon fixation device according to claim 1, wherein the gas introduced into the reaction chamber from the supply means has a carbon dioxide concentration of 10 to 80 vol %.

3. 3. The carbon fixation device according to claim 1, further comprising: a separator disposed downstream of the reaction chamber and capable of separating carbon dioxide and carbon monoxide; and a circulation means for supplying the gas from which carbon monoxide has been separated by the separator to the supply means.

4. A carbon fixation device as described in claim 1, comprising: a power generation means for generating electricity using the energy of gas supplied from the reaction chamber in accordance with the reaction; and an exhaust means for exhausting residual gas from the power generation means.

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