KR102130971B1 - Stabilizing electric power system using plasma reforming module - Google Patents

Abstract

The present invention relates to a system for stabilizing a power system by adjusting the frequency of a power system using a plasma reforming module and producing chemical energy, and the variable frequency generated due to a mismatch between demand power and supply power in the power system The stability of the power system can be secured by demanding generated power to return to the standard frequency, and useful chemical energy can be produced by driving the plasma reforming module with the generated power.

Description

Stabilizing electric power system using plasma reforming module}

The present invention relates to a power system stabilization system using a plasma reforming module.

Here, background arts related to the present disclosure are provided, and they do not necessarily mean known technologies.

The thermal power plant predicts electric power demand and operates coal-fired power generation to produce the predicted electric power and transmit it to consumers through the electric power grid. At this time, the power plant has a reserve ratio according to the maximum demand, and generally generates more power than expected. However, due to a variety of causes, there are many things beyond the expected demand, and power generation and supply is unstable because renewable energy generation connected to a grid is difficult to generate a desired amount of power at a desired time.

The power generation method of the power plant can be divided into the base power generation method mainly used in thermal power plants and the peak load generation method mainly used in gas power plants. The base power generation method is a method in which regular operation is performed because the time required for operation is long, and the peak load generation method is a method in which operation is performed when power consumption is rapidly increased because it takes less time from stationary to power generation.

On the other hand, when the power is supplied from the power plant, the frequency fluctuates due to a mismatch between the demand power and the power supply of the power plant. The power plant adjusts the power generation power to immediately respond to the changing load momentarily through frequency adjustment. The standard frequency of Korea's power system is 60 Hz. When the power demand increases and the supply power is insufficient, the frequency drops below 60 Hz, so the power is raised to adjust the frequency, and when the power demand decreases and the supply power remains, the frequency exceeds 60 Hz. The frequency has been adjusted through the following driving method.

In a power plant, a governor, which is a device that corrects a moving centrifugal weight due to a change in rotational speed and changed centrifugal force due to a change in frequency, is used to return the changed frequency caused by a mismatch between demand and supply power to a standard frequency. do.

On the other hand, the boiler uses fuel and air to produce feed water as steam, and then sends it to the turbine system, and the turbine is connected to the generator to control the amount of steam introduced to control the mechanical force by steam to maintain 60 Hz of the power system. Adjust using a valve. Since the steam supplied from the boiler to the turbine has a time delay, even if the steam valve is opened, the steam cannot be supplied immediately, so the instantaneous steam demand can be controlled by the steam supplied from the boiler to the turbine. If required, a time delay occurs because steam must be produced and supplied.

Therefore, there is a time delay in producing and supplying steam required by the turbine by evaporating water by burning boiler fuel. Due to this delay, the frequency does not immediately recover to 60 Hz, and there is a problem that the generator converges to 60 Hz with a time delay depending on how much power the generator supplies.

In the case of the frequency following operation method in which the generator output is immediately adjusted when a frequency fluctuation occurs using the speed governor as described above, the operation cost is high and the generator efficiency is different for each power plant. The reduction may result, and there is a problem that the failure rate of power plant equipment is increased.

Another method is to convert electrical energy, such as surplus power, into chemical energy. Produce hydrogen through electrolysis of water using generated surplus power or renewable energy, and use the produced hydrogen and carbon dioxide generated from thermal power generation. In order to manufacture diesel fuel or methanol.

However, the method of producing and storing hydrogen using electric energy also requires an additional chemical plant for storing hydrogen, and it takes time and money to operate it, and transport infrastructure that transports difficult-to-handle hydrogen to the place of use. There is a problem to be built.

Meanwhile, a reforming process is a process of changing a structure in order to improve the quality of hydrocarbons, and mainly uses a catalytic reforming method using a catalyst. The reforming reaction is an endothermic reaction in which a reactant having a relatively small energy is converted into a product having a large energy, and a high temperature and pressure should be applied in the presence of a catalyst.

The catalytic reforming method is mainly applied to a large-scale chemical plant, and since it is necessary to set reaction conditions, it is impossible to immediately drive it, and it is impossible to provide a general-purpose facility applicable to any plant. Therefore, when the reaction time is accumulated, there is a problem that a carbon deposition problem occurs and a conversion rate is lowered.

1. Korea Registered Patent No. 10-1474296 (2014.12.12.) 2. Korean Patent Publication No. 10-2017-0029274 (2017.03.15)

The present invention is to solve the above problems and to provide a system capable of stabilizing the power system at a more efficient and reduced cost and further producing chemical energy compared to power control by frequency regulation.

However, the objects of the present invention are not limited to those mentioned above, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

The present invention is a power system stabilization system capable of stabilizing a power system by adjusting the frequency of a power system using a plasma reforming module, and driving and stopping the plasma reforming module according to the frequency of the power system through a monitoring module and a control module. By providing a power system stabilization system with adjustable frequency.

In addition, the control module is characterized in that the frequency of the power system is lowered by increasing the load by driving the plasma reforming module when the frequency of the power system exceeds a specified frequency.

In addition, the control module primarily determines whether the frequency of the power system corresponds to a frequency dead band region that is a region within a predetermined range up and down based on a specified frequency, and when the frequency is not within the frequency dead band region, the plasma reforming module It is characterized in that the plasma reforming module is driven when the plasma reforming module is acceptable by secondarily determining whether it is acceptable.

In addition, the control module adjusts the frequency through the steam valve of the power system when it corresponds to the frequency dead zone through the primary determination, and the power system when the plasma reforming module is not acceptable through the secondary determination. It is characterized by adjusting the frequency through the combustion control.

In addition, the control module includes a master control module and at least one auxiliary control module, and the auxiliary control module modulates each of the plasma modification modules into at least one plasma modification module to control each plasma modification module. And, the master control module is characterized in that it controls the driving and stop of the entire modulated plasma reforming module by controlling the auxiliary control module.

In addition, the plasma reforming module is characterized in that the inductively coupled plasma reforming module.

In addition, the inductively coupled plasma reforming module includes a first reactor that is a dielectric discharge tube and an antenna that is an induction coil arranged to surround the first reactor, and is driven using power of a power system to cause a reforming reaction of a feedstock. It is characterized by a module that generates an inductively coupled plasma that provides energy.

In addition, the plasma reforming module is characterized in that the module for producing a synthesis gas containing carbon monoxide and hydrogen by using a mixed gas containing carbon dioxide and methane as a feedstock.

In addition, the present invention, the inductively coupled plasma reforming module, a first reactor formed of a dielectric extending in the longitudinal direction; And a first induction coil structure disposed to surround the first reactor and generating an inductively coupled plasma in the first reactor, wherein the first induction coil structures are connected in series with each other and disposed on different layers, respectively. Induction coils of the same structure having at least two turns in each layer; And auxiliary capacitors disposed between induction coils adjacent to each other to distribute the voltage applied to the induction coils.

In addition, the present invention stabilizes the power system by adjusting the frequency of the power system using an inductively coupled plasma reforming module and produces chemical energy. The inductively coupled plasma according to the frequency of the power system through a monitoring module and a control module. A power system stabilization system capable of adjusting the frequency of the power system by driving and stopping a reforming module; And a chemical energy production system that produces chemical energy by using the power of the power system and providing energy so that a reforming reaction of a feedstock can occur through an inductively coupled plasma reforming module driven by the power system stabilization system. Provided is a power system stabilization and chemical energy production system using an inductively coupled plasma reforming module.

The present invention can provide the stability of the power system and produce chemical energy by demanding the generated power to return the fluctuating frequency generated due to the mismatch between demand power and supply power in the power system to a standard frequency. More specifically, the plasma reforming module may be driven with the generated power to generate a synthesis gas containing carbon monoxide and hydrogen from a mixed gas containing carbon dioxide and methane, and convert the generated synthesis gas into useful chemical energy such as diesel or methanol. have.

In addition, the plasma reforming module according to the present invention can produce the synthesis gas by using about 1/4 of the power compared to the system for producing the synthesis gas after producing hydrogen through electrolysis. In addition, since instantaneous operation is possible when power is generated, discontinuous renewable energy can be used as power. Also, due to the continuous module structure, it can be applied to a variety of mixed gas scales from small to large, and catalysts for reforming reactions It is not necessary and can provide a high conversion rate.

In addition, the chemical energy production system using the inductively coupled plasma reforming module according to the present invention is a system that is applied to a power plant and controls the amount of power generation to reduce the flow current and convert the stored current into chemical energy and store it. Compared to the regulating method, it is possible to reduce the cost of maintaining power quality or efficiency, and yet to generate useful energy.

1 is a schematic diagram of a system according to an embodiment of the present invention.
2 shows a control module configuration according to an embodiment of the present invention.
3A and 3B show a control algorithm of a control module according to an embodiment of the present invention.
4 is a schematic diagram of an inductively coupled plasma reforming module according to an embodiment of the present invention.
5 shows a modular configuration of a chemical energy production system according to an embodiment of the present invention.
6A is a conceptual diagram illustrating an inductively coupled plasma generator according to an embodiment of the present invention.
6B is a circuit diagram illustrating the inductively coupled plasma generator of FIG. 6A.
6C is a view for explaining the voltage distribution of the inductively coupled plasma generator of FIG. 6A.
6D is a plan view illustrating the inductively coupled plasma generator of FIG. 6A.
6E is a plan view illustrating the induction coil of the inductively coupled plasma generating device of FIG. 6A.

Before describing the present invention in detail below, it is understood that the terms used herein are only for describing specific embodiments and are not intended to limit the scope of the present invention, which is limited only by the scope of the appended claims. shall. All technical and scientific terms used in this specification have the same meaning as commonly understood by those of ordinary skill in the art unless otherwise stated.

Throughout this specification and claims, unless otherwise stated, the terms comprise, comprises, comprising means referring to the stated article, step or group of articles, and steps, and any any other article. It is not meant to exclude a step or group of things or a group of steps.

On the other hand, various embodiments of the present invention can be combined with any other embodiments, unless otherwise indicated. Any feature indicated as particularly preferred or advantageous may be combined with any other feature or features indicated as preferred or advantageous. Hereinafter, embodiments and effects according to the present invention will be described with reference to the accompanying drawings.

The power system stabilization and chemical energy production system using the plasma reforming module according to an embodiment of the present invention generates power instead of adjusting the frequency to return the generated frequency due to the mismatch between demand power and supply power in the power plant to the standard frequency. It is a system that manufactures syngas using a plasma reforming module that can immediately demand, and produces chemical energy such as diesel or methanol therefrom. 1 shows a schematic diagram of a system according to an embodiment of the present invention.

The power system stabilization system using the plasma reforming module according to an embodiment of the present invention may stabilize the power system by adjusting the frequency of the power system using a plasma reforming module capable of driving or stopping at a high speed.

More specifically, as shown in FIG. 2, the power system stabilization system according to an embodiment of the present invention first detects the voltage and frequency of the power system by using a monitoring module such as SCADA, and the operating state of the power source and the plasma reforming module. Grasp the status of When the specified frequency is exceeded using the obtained data and a control module such as DCS, it is determined whether or not the plasma reforming module is operated according to the amount of excess power.

For example, when the power demand decreases and the supply power remains, the frequency exceeds 60 Hz, so the frequency of the power system can be adjusted by increasing the load by driving the plasma reforming module to reduce the frequency.

The control module includes a master control module and at least one auxiliary control module. The auxiliary control module serves to control each plasma modification module when configuring a system by modulating with at least one plasma modification module, and the master control module controls the auxiliary control module to modulate the whole It serves to control the driving and stopping of the plasma reforming module.

The master control module can be controlled through an algorithm as shown in FIG. 3. As shown in FIG. 3, it is first determined whether the measured frequency is a frequency dead zone. In order to prevent the plasma reforming module from frequently responding to frequency changes, within a certain range (eg, one plasma modulating module or less, frequency dead zone) based on a specified frequency (for example, 60 Hz). Without driving the plasma reforming module, the generator's speed governor senses this and adjusts the output to maintain the frequency at 60 Hz. In this case, the steam valve supplied from the boiler of the power plant to the turbine should be in an adjustable range.

If it is determined that the frequency is in the dead zone, the frequency can be adjusted through the adjustment of the steam valve, or through the battery energy storage system (BESS) of the power system. The battery energy storage device stores the supplied electrical energy in a battery or the like, and the electrical energy stored in the battery energy storage device may be supplied to the outside again as necessary. Therefore, when it is determined that the frequency is in the dead zone, the frequency can be adjusted by storing electrical energy in the battery energy storage device or providing stored power to the outside. If a battery energy storage device is used, more stable frequency adjustment is possible, and the power plant can be operated without flash generation.

On the other hand, if the measured frequency does not correspond to the frequency dead zone, the control module determines whether the plasma reforming module is acceptable according to the operating state of the plasma reforming module and adjusts the frequency by driving the plasma reforming module if it is acceptable. If it is deemed unacceptable, adjust the frequency through the boiler combustion control of the power plant.

The control module generates power by using surplus power produced in excess of demand power from power plants, such as thermal power plants and nuclear power plants, as well as frequency control, as well as fluctuating power, or by using renewable energy, such as solar power and wind energy, which are unstable. The stable operation of the circle is possible. Preferably, it is good to use electric power produced in a thermal power plant because carbon dioxide (CO ₂ ), which is essential in thermal power generation, can be directly used as a feedstock for the reforming reaction.

Through the power system stabilization system using the plasma reforming module, frequency can be adjusted in a real-time grid power generation stage and a transmission network, and the stability of the power generation source according to the contracted quantity of power generation (day, day, real-time) between the power exchange and the power generation company Considering the efficiency and efficiency, the planned production of chemical energy using the plasma reforming module is possible.

The plasma reforming module of the power system stabilization system according to the present invention may use any type of plasma generating device such as an inductive coupling method, a torch method or a microwave plasma method, and preferably, an inductively coupled plasma reforming module. When using the inductively coupled plasma reforming module, there is an advantage in terms of efficiency in terms of chemical energy production, which will be described later, compared to a plasma torch or microwave plasma method. The specific configuration of the inductively coupled plasma reforming module will be described later.

A chemical energy production system using an inductively coupled plasma reforming module according to an embodiment of the present invention may be operated when a control signal for driving a plasma reforming module is transmitted in the power system stabilization system.

The inductively coupled plasma reforming module includes a first reactor (dielectric discharge tube) in which a reforming reaction takes place and is driven using power of a power plant to provide high energy for a reforming reaction of a feedstock. To generate a plasma. In the present specification, carbon dioxide (CO ₂ ) reforming to produce syngas including carbon monoxide (CO) and hydrogen (H ₂ ), including carbon dioxide (CO ₂ ) and methane (CH ₄ ) as feedstocks, is an example. As described.

The feedstock can be supplied by capturing carbon dioxide from flue gas emitted after combustion in a thermal power plant. In addition, carbon dioxide (CO ₂ ) and methane (CH ₄ ) can be collected and supplied from biogas generated in a waste treatment facility. In addition, the feedstock can be supplied through various routes including purchase.

The feedstock is regulated at a constant flow rate in the supply line, mixed thoroughly with vaporized water vapor, and introduced into the plasma reforming module (or first reactor). Water vapor (H ₂ O) is introduced at a ratio of 1.0 to 2.0 moles compared to the number of moles of methane.

Plasma reforming module according to an embodiment of the present invention is an inductively coupled plasma generating module, wherein the inductively coupled plasma reforming module is applied with a high potential at an antenna (induction coil) arranged to surround a dielectric discharge tube serving as a first reactor. When the plasma is generated in the dielectric discharge tube, the surface of the dielectric discharge tube is heated by the collision of ions to generate the synthesis gas by providing energy required for reforming the feedstock supplied into the dielectric discharge tube. 4 is a schematic diagram of a plasma reforming module according to an embodiment of the present invention.

The inductively coupled plasma reforming module receives a control signal and when the driving starts, the time until the reforming reaction is stably performed (normal operation) is within a few minutes to several hours. Compared to the time taken for this to be more than tens of hours (24 to 72 hours), there is an advantage that driving and stopping are possible immediately.

In addition, the inductively coupled plasma reforming module has an advantage of excellent conversion efficiency compared to a plasma torch or microwave plasma method capable of generating plasma. More specifically, plasma torch has shortcomings due to electrode consumption, and microwave plasma is costly and difficult to control, making mass production difficult and energy conversion efficiency less than 60%, whereas inductively coupled plasma uses electrodes Because it does not have excellent durability, it can be mass-produced at a low cost, and has the advantages of a carbon dioxide conversion rate of 80% or more and energy conversion efficiency of 60% or more.

The inductively coupled plasma reforming module may be modularized by including at least two or more inductively coupled plasma reforming modules in parallel or in series as a unit module. Also, as shown in FIG. 5, a second reactor for producing various kinds of hydrocarbon compounds from syngas is connected (1×1) or a plurality of (N) inductively coupled plasma reforming modules to the rear end of the inductively coupled plasma reforming module. In may be a buffer tank for storing the synthetic gas produced by operating variably according to the power supply and a second reactor for producing chemical energy from the synthetic gas stored in the buffer tank may be connected (N×1). In addition, a plurality of second reactors may be connected to the rear end of one plasma reforming module (1×N), or a plurality of second reactors may be connected to the rear end of the plurality of plasma reforming modules (N×N) to be modularized in various connection types. Can. The connection form as described above may also be composed of plural (M) pieces ((1×1)×M, (N×1)×M, (1×N)×M, (N×N)×M), It is possible to provide an optimal system configuration according to the power generation capacity and the situation.

The detailed configuration of the inductively coupled plasma reforming module according to an embodiment of the present invention will be described later.

In the present invention, the mixed gas produced through the plasma reforming module flows into the second reactor, and produces chemical energy such as diesel or methanol in the second reactor. For example, a process of producing methanol through a Fischer-Tropsch reaction using a catalyst may be performed.

The methanol synthesis reaction is performed using a catalyst, and a Cu-Zn-Al-based oxide or a Cu-Zn-Al-Zr-based oxide catalyst supported on a cerium-zirconium oxide support may be used. When the catalyst is used, the generation of by-products is suppressed to improve the yield to methanol, and thus the methanol purification efficiency and carbon conversion efficiency according to the yield to methanol can be greatly improved.

When a biological water treatment facility exists in a power plant, the generated methanol is used as a carbon energy source in a desulfurization process to remove hydrogen sulfide generated in the wastewater treatment process or a denitrification process to nitrate the ammonia nitrogen contained in the wastewater and reduce it to nitrogen gas. Can be used. At this time, since methanol used for water treatment does not require high purity, it is possible to simplify the separation and purification process required to increase the purity of methanol.

Inductively coupled plasma reforming module

An inductively coupled plasma reforming module according to an embodiment of the present invention includes an antenna disposed to surround a dielectric discharge tube, and plasma is generated in the dielectric discharge tube when a high electric potential is applied to the antenna. The surface of the dielectric discharge tube is heated to 1000°C or more by collision of ions to provide energy necessary for the reforming reaction.

The high potential applied to the antenna can be affected by the inductance, frequency, and current of the antenna. At high power conditions, a high potential applied to the antenna necessarily appears. Therefore, it is necessary to lower the high potential generated in the antenna. The plasma reforming module according to the present invention can minimize the heating by ion collision by reducing the applied high voltage when high power of more than several kilowatts is applied.

The plasma reforming module generates an inductively coupled plasma and can be modeled as a transformer circuit. The induction coil can act as the primary coil of the transformer circuit, and the plasma can act as the secondary coil of the transformer circuit. Induction coil and antenna are used interchangeably below in the same sense.

In order to reduce the voltage applied to the induction coil, a capacitor is disposed between series-connected induction coils, so that the entire voltage can be divided between the induction coil and the capacitor. Specifically, the induction coil is divided to arrange auxiliary capacitors between the divided induction coils, and main capacitors may be respectively disposed at both ends of the induction coil. Accordingly, an electrostatic field due to a screening effect is reduced, and a voltage applied to the induction coil can be reduced by a voltage distribution model. The divided induction coil and the auxiliary capacitor constitute a series resonant circuit, and the resonant frequency of the resonant circuit may be the same as the driving frequency of the AC power. Accordingly, stable impedance matching may be performed while a low voltage is applied to the induction coil.

When performing the inductively coupled plasma discharge by applying RF power to the induction coil surrounding the dielectric discharge tube, the inductively coupled plasma heats the dielectric discharge tube, and the dielectric discharge tube is heated and damaged, thereby inducing high power of tens of kWatt or more. The combined plasma has structural limitations.

Therefore, the present invention is to improve the efficiency or stability of the inductively coupled plasma, 1) an antenna of a multi-layer structure (coil structure) to increase the strength of the induction electric field, 2) divide the induction coil and reduce the impedance between the divided induction coils. For the capacitor connection structure, 3) the structure for connecting the main capacitor to both ends of the induction coil to satisfy the overall resonance condition, 4) improving the plasma stability of the induction coil, and applying a variable frequency AC power supply.

Accordingly, a flow rate of tens to hundreds of liters per minute, which the conventional inductively coupled plasma apparatus cannot perform, can be stably processed at a high pressure of several torr or more. In addition, an electrode for a separate initial discharge is not required, and initial discharge is performed in a state in which the driving frequency of the AC power source is out of resonance. When it deviates from the resonance condition, high voltage is applied to the induction coil to perform initial discharge. Subsequently, a main discharge is performed by changing the driving frequency of the AC power source to a resonance condition.

In the case of an inductively coupled plasma (ICP) antenna, the intensity of the induction electric field transmitted to the plasma is proportional to the current and frequency of the induction coil, and is proportional to the square of the number of turns (reel). Therefore, the higher the number of windings of the induction coil (or antenna), the higher the electric field can be applied to the plasma. However, as the number of turns of the solenoid coil increases, energy is distributed in the longitudinal direction of the dielectric discharge tube due to spatial constraints. In addition, the high inductance (impedance) of the induction coil makes it difficult to transfer power from the RF power generator to the induction coil (antenna).

Since the density of the electric field formed around the plasma needs to be increased, the number of turns per unit length should be maximized with respect to the length direction of the dielectric discharge tube. When a high voltage is applied to the induction coil, the induction coil forms a capacitively coupled plasma to reduce discharge stability. The capacitively coupled plasma is advantageous for initial discharge, but causes damage to the dielectric discharge tube by ion acceleration due to capacitive coupling.

According to an embodiment of the present invention, in order to solve the problem of dielectric discharge tube damage due to high voltage applied to the antenna, a capacitor is inserted between unit antennas disposed in each layer. Thus, even when more power was applied to the antenna, the dielectric discharge tube did not break. A capacitor is used between the unit antennas, and the voltage applied to the antenna is reduced. In addition, parasitic discharge due to high voltage between the antenna and the power input terminal and the power output terminal is suppressed.

When a high voltage is applied to the antenna, ions accelerate and collide with the surface by high voltage, causing high temperature heat generation and damage. Due to this problem, it is difficult to apply a high power condition to an inductively coupled plasma, and the inductance is reduced or the antenna is dropped from the tube.

According to an embodiment of the present invention, when a capacitor that offsets a voltage appropriately between the unit antennas constituting the antenna is positioned in series, the maximum potential decreases in inverse proportion to the number of times the antenna is divided, and even at high power, Breakage is alleviated.

Hereinafter, preferred embodiments of the plasma reforming module will be described in detail with reference to the accompanying drawings.

The plasma reforming module 100 may generate a plasma of high efficiency at a high pressure of several torr or more. The plasma reforming module 100 may include an induction discharge unit 101 and an RF power supply 140 that supplies power to the induction discharge unit 101. The plasma reforming module 100 may generate an inductively coupled plasma to produce syngas from a feedstock and provide it to the second reactor.

6A is a conceptual diagram illustrating a plasma reforming module according to an embodiment of the present invention. FIG. 6B is a circuit diagram illustrating the plasma reforming module of FIG. 6A. 6C is a view for explaining the voltage distribution of the plasma reforming module of FIG. 6A. 6D is a plan view illustrating the plasma reforming module of FIG. 6A. 6E is a plan view illustrating the induction coil of the plasma reforming module of FIG. 6A.

6A to 6E, the plasma reforming module 100 includes a dielectric tube 130 extending in the longitudinal direction; A first induction coil structure 110 disposed to surround the dielectric tube and generating an inductively coupled plasma in the dielectric tube; An RF power supply 140 that provides positive and negative outputs of opposite phases to each other, supplies positive and negative outputs of RF power to both ends of the first induction coil structure, and changes driving frequencies; A first main capacitor 121 disposed between the positive output terminal of the RF power supply and one end of the first induction coil structure; And a second main capacitor 122 disposed between the negative output terminal of the RF power supply and the other end of the first induction coil structure.

The first induction coil structures 110 are connected to each other in series, disposed on different layers, and induction coils 112, 114, 116, and 118 having at least one turn in each layer; And auxiliary capacitors 113, 115 and 117 disposed between adjacent induction coils to distribute voltage applied to the induction coils.

The driving frequency of the RF power supply 140 may be several hundred kHz to several MHz. The output power of the RF power supply 140 may be hundreds of watts to tens of kilowatts. The RF power supply 140 supplies power to a time-varying load (inductively coupled plasma) through a first induction coil structure using floating power. The induction coil of the first induction coil structure 110 may be electromagnetically coupled to an inductively coupled plasma. Therefore, a device capable of matching impedance between the RF power supply 140 and the first induction coil structure 110 may be required. The RF power supply 140 may have first and second outputs of opposite phases. At a specific time, the first output and the second output may have opposite phases with respect to ground.

Conventional impedance matching networks perform impedance matching using two variable reactance elements (eg, vacuum variable capacitors) or transformers. In this case, the first induction coil structure 110 is difficult to meet the driving frequency and stable resonance conditions. Therefore, in the first induction coil structure, an RF power source having a variable driving frequency is used so that a pair of induction coils and auxiliary capacitors adjacent to each other satisfy a series resonance condition.

The dielectric tube 130 is cylindrical and may extend in the longitudinal direction. The material of the dielectric tube 130 may be a glass, quartz, ceramic, alumina, or sapphire material that can withstand high temperatures.

The cylindrical plasma reforming module includes a cylindrical dielectric discharge tube and an antenna surrounding the discharge tube. In the cylindrical inductively coupled plasma, the induced electric field does not perpendicularly enter the dielectric discharge tube, so damage due to ion bombardment is small. The cylindrical inductively coupled plasma generates an induction electric field in the direction of the central axis of the cylindrical dielectric discharge tube. However, when a high voltage is applied to the antenna, the antenna generates a capacitively coupled plasma to heat the dielectric tube. Therefore, a new induction coil structure is required to prevent high voltage from being applied to the antenna.

In the first induction coil structure 110, the induction electric field depends on the driving wave number and the current (or the number of turns per unit length). In addition, the maximum voltage applied to the first induction coil structure 110 depends on the total impedance and current of the first induction coil structure 110. The impedance of the first induction coil structure 110 depends on the inductance and driving frequency of the first induction coil structure. Therefore, in order to reduce the maximum voltage applied to the first induction coil structure, when the inductance of the first induction coil structure is increased, the intensity of the induction electric field increases, but the power storage coupling effect increases by a high maximum voltage. Therefore, in order to reduce the impedance of the first induction coil structure, the first induction coil structure 110 includes a plurality of induction coils 112, 114, 116, 118 and auxiliary capacitors 113, 115, 117 inserted between adjacent induction coils. . In addition, the induction coil and the auxiliary capacitor adjacent to each other constitute a series resonant circuit. The induction coils and the auxiliary capacitors are alternately arranged in a battery and connected in series with each other. Accordingly, the first induction coil structure provides a low impedance as a whole. The number of auxiliary capacitors may be less than the number of induction coils.

In addition, the first induction coil structure 110 constitutes a complete resonant circuit as a whole. To this end, the first main capacitor 121 is connected to one end of the first induction coil structure 110, and the second main capacitor 122 is connected to the other end of the first induction coil structure 110. On the other hand, in order to construct a perfect resonant circuit, the capacitance C2 of the first main capacitor 121 may be twice (2C1) of the capacitance C1 of the auxiliary capacitor.

When such a resonant circuit is configured, the maximum voltage applied to the first induction coil structure 110 is inversely proportional to the number of times divided by each induction coil.

The first induction coil structures 110 are connected to each other in series, disposed on different layers, and induction coils 112, 114, 116, and 118 having at least one turn in each layer; And auxiliary capacitors 113, 115 and 117 which are respectively disposed between adjacent induction coils to distribute the voltage applied to the induction coils.

The induction coils include first to fourth induction coils 112, 114, 116, 118. The auxiliary capacitor includes first to third auxiliary capacitors 113, 115 and 117. The inductances of each of the first to fourth induction coils 112, 114, 116, and 118 are the same and L1. In addition, each of the first to third auxiliary capacitors 113, 115 and 117 has the same capacitance and is C1. Each of the first to third auxiliary capacitors 113, 115 and 117 may be displayed as a pair of virtual capacitors connected in series with 2C1. Accordingly, the first main capacitor 121, the first induction coil 112, and the virtual capacitor may form a resonant circuit to reduce the voltage as a whole.

Compared to the case where the auxiliary capacitors 113, 115 and 117 are not connected, by connecting the auxiliary capacitor, the voltage decreases in inverse proportion to the number of induction coils. Nevertheless, the total number of turns per dielectric tube unit length is maintained. In order to satisfy this resonance condition, the driving frequency may be controlled to match the resonance frequency.

In addition, each of the induction coils 112, 114, 116, and 118 may be a 3 turn coil or a 4 turn coil in order to further increase the number of turns per unit length of the dielectric tube to increase the strength of the induction electric field. The induction coils 112, 114, 116, and 118 are stacked vertically sufficiently densely with each other and require space for electrical connection. In order to satisfy this, each induction coil does not have a portion for jumping the placement plane, and the input and output terminals of each induction coil should not be disposed in a region where they are stacked with each other. To this end, the following induction coil is proposed.

The induction coil includes first to fourth induction coils 112, 114, 116, and 118, which are sequentially stacked. The auxiliary capacitor includes first to third auxiliary capacitors 113, 115 and 117.

The auxiliary capacitor between each induction coil reverses the potential. That is, in the same plane of placement, the turns close to the dielectric tube (first arc portion) and the farthest turn (fourth arc portion) are induced to be opposite potentials. Inside the dielectric tube, the electric potential of the induction coil is canceled so that an electrostatic electric field due to capacitive coupling to the dielectric tube does not appear. This reduction in electrostatic electric field reduces the effect of power storage coupling.

In general antennas, a large potential difference occurs at both ends due to inductance, and a large potential difference accelerates ions to cause energy loss and damages by heating the dielectric tube. However, the auxiliary capacitor placed between the induction coils reduces the potential difference, and sets the potentials inside and outside each induction coil opposite to each other. Accordingly, the potentials of opposite signs act as a dipole field in the dielectric tube to reduce the electrostatic electric field. Each of the induction coils 112, 114, 116, and 118 may include a plurality of windings wound from inside to outside in the same plane.

The first induction coil 112 is disposed to surround the dielectric tube. The second induction coil 114 is rotated 90° counterclockwise in preparation for the case where the first induction coil 112 is disposed, and is arranged under the first induction coil 112. The third induction coil 116 is rotated 90° counterclockwise in preparation for the case where the second induction coil 114 is disposed, and is arranged under the second induction coil 114. The fourth induction coil 118 is arranged to be aligned with the lower portion of the third induction coil 116 by rotating 90° counterclockwise in preparation for the case where the third induction coil 116 is disposed. One end of the first induction coil 112 is connected to the positive output terminal of the RF power supply 140 through the first main capacitor 121. The other end of the first induction coil 112 is connected to one end of the second induction coil 114 through the first auxiliary capacitor 113. The other end of the second induction coil 114 is connected to one end of the third induction coil 116 through the second auxiliary capacitor 115. The other end of the third induction coil 116 is connected to one end of the fourth induction coil 118 through the third auxiliary capacitor 117. The other end of the fourth induction coil 118 is connected to the negative output terminal of the RF power supply 140 through the second main capacitor 122. The first to fourth induction coils may be sequentially stacked by rotating by 90° to maintain azimuth symmetry as a whole.

The voltage of the innermost winding of each of the induction coils (eg, 2V) may have a phase opposite to the voltage of the outermost winding (eg, -2V). Also, the voltages of the innermost windings of all induction coils may be the same. Accordingly, parasitic capacitance between adjacent induction coils is minimized, and discharge characteristics can be improved. In addition, since the plasma inside the dielectric tube sees the same voltage by the inner windings, local ion sputtering can be reduced.

The induction coil is divided, and an auxiliary capacitor is inserted between the divided induction coils to reduce the maximum voltage. However, in order to provide a sufficient induction electric field, it is necessary to increase the number of turns per unit length. In order to increase the number of turns per unit length, the number of turns of each induction coil 112, 114, 116, 118 is increased. However, each induction coil needs to be arranged in the same plane. If each induction coil has wiring out of the plane of arrangement, it may interfere with the dense stacking of the induction coils disposed in adjacent layers. Each induction coil may have 3 or 4 turns in the same plane.

Each of the induction coils (112, 114, 116, 118) has a first central angle (x-axis direction) and an open portion in a rectangular coordinate system, as shown in FIG. 1 circular arc portion 22a; And a second central angle having a second central angle equal to or less than the first central angle, and having a second radius greater than the first radius and having the same central axis as the central axis of the first arc portion 22a. Circular arc portion 22b; A third arc portion 22c disposed on the arrangement plane with a third center angle less than or equal to the second center angle, and having a third radius greater than the second radius and having the same central axis as the center axis of the first arc portion ; A fourth arc portion 22d disposed on the arrangement plane with a fourth center angle less than or equal to the third center angle, and having a fourth radius greater than the third radius and having the same central axis as the center axis of the first arc portion ; A first connection portion 23a disposed on the arrangement plane and connected to one end of the first arc portion 22a and extending in the first direction (x-axis direction); A first arc connecting portion 24a having a “U” shape which is disposed on the arrangement plane and connects the other end of the first arc portion 22a to one end of the second arc portion 22b; A second circular arc connecting portion (24b) having a “U” shape, which is disposed on the arrangement plane and connects the other end of the second circular arc portion with one end of the third circular arc portion; A third circular arc connecting portion (24c) having a “U” shape, which is disposed on the arrangement plane and connects the other end of the third circular arc portion with one end of the fourth circular arc portion; And a second connection portion 23b disposed on the arrangement plane and connected to the other end of the fourth arc portion 22d and extending in the first direction. The fourth center angle may be 270° or more. The first arc connecting portion 24a, the second arc connecting portion 24b, and the third arc connecting portion 24c may be disposed so as not to overlap each other. The first arc connecting portion 24a may be disposed within the area defined by the second arc connecting portion 24b.

In each of the induction coils 112, 114, 116, and 118, the spacing between the windings (eg, the first arc portion to the fourth arc portion) may be constant. For example, the gap may be 1 mm to 3 mm. In order for the induction coil to provide sufficient azimuth symmetry, the first to fourth center angles may be 270° or more. On the other hand, the first arc portion to the fourth arc portion can maintain a sufficient distance of several millimeters or more in order to suppress the arc discharge at atmospheric pressure due to the voltage difference.

Induction coils disposed on adjacent layers may be electrically insulated by the insulating spacer 150. The insulating spacer 150 may be inserted into an outer surface of the dielectric tube 130 in the form of a washer, and may be in the form of a thin disc having a through hole in the center. The insulating spacer 150 may be glass, plastic, or Teflon. The thickness of the insulating spacer 150 may be on the order of millimeters. The inner radius of the insulating spacer 150 may be substantially the same as the outer radius of the dielectric tube 130, and the outer radius of the insulating spacer 150 may be substantially the same as the outermost radius of the induction coil. The width between the inner and outer diameters of the insulating spacer 150 may be several centimeters to tens of centimeters.

Meanwhile, at least a portion of the induction coils 112, 114, 116, and 118 may be molded by a ceramic paste. The ceramic mold 152 surrounding at least a portion of the induction coil may be in thermal contact with the dielectric tube 130. Accordingly, when a refrigerant flows in the induction coils 112, 114, 116, and 118, the cooled induction coil cools the ceramic mold 152, and the ceramic mold 152 can indirectly cool the dielectric tube 130. have.

Each of the induction coils 112, 114, 116, and 118 has a four-fold outward direction from the dielectric tube on each layer. A pair of induction coils of adjacent layers are connected in series through an auxiliary capacitor connected in series therebetween. Accordingly, the capacitance of the auxiliary capacitor cancels out the inductance of the induction coil. The four induction coils form a group. The four induction coils are arranged at 90° intervals counterclockwise.

Both ends of the dielectric tube may be sealed by a flange. The upper flange 132 may include a nozzle 131 that fixes one end of the dielectric tube and provides carbon dioxide. The induction coils 112, 114, 116, and 118 surrounding the central portion of the dielectric tube generate an inductively coupled plasma in the dielectric tube. The lower flange 134 fixes the other end of the dielectric tube, and a gas that can be further decomposed by the inductively coupled plasma may be provided at the other end of the dielectric tube.

The features, structures, effects, and the like exemplified in each of the above-described embodiments may be combined or modified for other embodiments by a person having ordinary knowledge in the field to which the embodiments belong. Therefore, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

100: plasma reforming module
110: first induction coil structure
112,114,116,118: induction coil
113,115,117: auxiliary capacitor
121: first main capacitor
122: second main capacitor

Claims (11)

As a power system stabilization system that can stabilize the power system by adjusting the frequency of the power system using a plasma reforming module,
A monitoring module for grasping the frequency of the power system and the state of the plasma reforming module; And
Firstly, it is determined whether the frequency of the power system measured by the monitoring module corresponds to a frequency dead zone, which is an area within a predetermined range up and down based on a prescribed frequency.
If it does not fall within the frequency dead zone, it is secondly determined whether the plasma reforming module is acceptable,
A control module capable of using surplus power or renewable energy produced in excess of demand power at a power plant; Including,
A power system stabilization system capable of adjusting the frequency by driving and stopping the plasma reforming module according to the frequency of the power system through the monitoring module and the control module.
According to claim 1,
The control module lowers the frequency of the power system by driving the plasma reforming module to increase the load when the frequency of the power system exceeds a specified frequency.
According to claim 1,
When the plasma reforming module is acceptable, power system stabilization system, characterized in that to drive the plasma reforming module.
According to claim 2,
The control module adjusts the frequency through the steam valve of the power system when it corresponds to the frequency dead zone through the first determination, and if the plasma reforming module is not acceptable through the second determination, the power system Power system stabilization system characterized by adjusting the frequency through the combustion control.
According to claim 2,
The control module adjusts the frequency through the battery energy storage system of the power system when it corresponds to the frequency dead zone through the primary determination, and the plasma reforming module is accommodated through the secondary determination. If not possible, the power system stabilization system, characterized in that to adjust the frequency through the combustion control of the power system.
According to claim 1,
The control module includes a master control module and at least one auxiliary control module,
The auxiliary control module modulates at least one plasma modification module to control each plasma modification module when configuring a system,
The master control module is a power system stabilization system, characterized in that to control the driving and stop of the entire modulated plasma modulating module by controlling the auxiliary control module.
According to claim 1,
The plasma reforming module is an inductively coupled plasma reforming module, characterized in that the power system stabilization system.
The method of claim 7,
The inductively coupled plasma reforming module includes a first reactor that is a dielectric discharge tube and an antenna that is an induction coil disposed to surround the first reactor, and is driven using power of a power system so that a reforming reaction of the feedstock can occur. Power system stabilization system, characterized in that the module for generating an inductively coupled plasma that provides energy.
According to claim 1,
The plasma reforming module is a power system stabilization system, characterized in that the module for producing a synthesis gas containing carbon monoxide and hydrogen by using a mixed gas containing carbon dioxide and methane as a feedstock.
The method of claim 7,
The inductively coupled plasma reforming module,
A first reactor formed of a dielectric extending in the longitudinal direction; And
It includes a first induction coil structure disposed to surround the first reactor and generating an inductively coupled plasma in the first reactor.
The first induction coil structure,
Induction coils of the same structure, connected in series with each other, disposed on different layers, and having at least two turns in each layer; And
And auxiliary capacitors disposed between adjacent induction coils to distribute voltage applied to the induction coils.
A system for stabilizing the power system and producing chemical energy by adjusting the frequency of the power system using a plasma reforming module,
A monitoring module for grasping the frequency of the power system and the state of the plasma reforming module; And
Firstly, it is determined whether the frequency of the power system measured by the monitoring module corresponds to a frequency dead zone, which is an area within a predetermined range up and down based on a prescribed frequency.
If it does not fall within the frequency dead zone, it is secondly determined whether the plasma reforming module is acceptable,
A control module capable of using surplus power or renewable energy produced in excess of demand power at a power plant; Including,
A power system stabilization system capable of adjusting the frequency of the power system by driving and stopping the plasma reforming module according to the frequency of the power system through the monitoring module and the control module; And
Plasma comprising; a chemical energy production system that produces chemical energy by using the power of the power system and providing energy so that a reforming reaction of a feedstock can occur through a plasma reforming module driven by the power system stabilization system Power system stabilization and chemical energy production system using reforming module.

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