JP2007022912A - Gas pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas pump that increases the quantity of a gas flow that can be processed substantially effectively by a solid electrolyte cylindrical body with a suitable diameter. <P>SOLUTION: Multiple units of a solid electrolyte cylindrical body unit 10' comprising a plurality of circular solid electrolyte cylindrical bodies 10a and 10b with different large and small diameters that are concentrically attached to be unitized are arranged on a concentric circle at even intervals making each of the central axes perpendicular. A dummy pipe 15 of a heat storage member is installed in the space surrounded by the plurality of solid electrolyte cylindrical body units 10'. A heater 40 of a ring shape heating means is concentrically arranged to the surrounding of the plurality of solid electrolyte cylindrical body units 10'. A gas G1 to be processed is flowed to an axial direction in each of units 10'. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solid electrolyte gas pump such as an oxygen pump or a hydrogen pump using an ion conductive solid electrolyte cylindrical body.

  The ion conductive solid electrolyte can transmit ions at a high temperature. Utilizing this phenomenon, it has been put to practical use in fuel cells, measurement of gas analysis, separation of gas mixtures and the like. When used as an oxygen pump, it is utilized that oxygen ions move through the oxygen ion conductive electrolyte from the cathode side to the anode where oxygen is generated under the potential gradient generated by reduction of oxygen and the like. ing.

  An outline of equipment such as a sample growing apparatus using the oxygen pump is shown in FIG. 5, and an outline of the oxygen pump is shown in FIG.

In FIG. 5, reference numeral 1 denotes an oxygen partial pressure control device, and an inert gas is supplied from a gas cylinder (not shown) through a valve 2. Usually, the oxygen partial pressure in the inert gas is about 10 ⁻⁴ atm. The oxygen partial pressure control device 1 controls a mass flow controller (MFC) 3 that controls the flow rate of the inert gas that has passed through the valve 2 to a set value, and controls the inert gas that has passed through the mass flow controller 3 to a target oxygen partial pressure. A possible electrochemical oxygen pump 4 and a supply gas oxygen sensor 5 for monitoring the oxygen partial pressure of the inert gas controlled by the oxygen pump 4 and supplying it to the next process (device) such as a sample growing device Have.

  The oxygen partial pressure control device 1 compares an oxygen partial pressure setting unit 6 for setting a desired oxygen partial pressure value and a monitor value by the oxygen sensor 5 with a set value by the oxygen partial pressure setting unit 6 and sends it out from the oxygen pump 4. An oxygen partial pressure control unit 7 that controls the oxygen partial pressure of the inert gas to be a predetermined value and an oxygen partial pressure display unit 8 that displays a monitor value by the oxygen sensor 5 are provided.

The electrochemical oxygen pump 4 of FIG. 6 has electrodes 4b and 4c made of platinum formed on both the inner and outer surfaces of a solid electrolyte cylindrical body 4a having oxide ion conductivity. The solid electrolyte cylindrical body 4a is, for example, a zirconia solid electrolyte, and is heated to about 700 ° C. by a heater (not shown). An inert gas is supplied in the axial direction from one opening of the solid electrolyte cylindrical body 4a toward the other opening. The inert gas is, for example, Ar + O ₂ (10 ⁻⁴ atm). A DC voltage of a DC power source E is applied between the inner and outer electrodes 4b and 4c. When a positive electrode is applied to the outer electrode 4c and a negative electrode is applied to the inner electrode 4b to flow a current I, oxygen molecules (O ₂ ) in the inert gas flowing through the solid electrolyte cylindrical body 4a are solid. It is electrically reduced by the electrolyte to be ionized (O ²⁻ ), and is released again as oxygen molecules (O ₂ ) through the solid electrolyte to the outside of the solid electrolyte cylindrical body 4a. Oxygen molecules released to the outside of the solid electrolyte cylindrical body 4a are exhausted together with an auxiliary gas such as air. The inert gas of Ar + O ₂ (10 ⁻⁴ atm) supplied to the solid electrolyte cylindrical body 4a becomes a treated gas in which oxygen molecules are reduced and controlled to the target oxygen partial pressure, and is used in the next step (apparatus). Be fed.

The oxygen pump 4 shown in FIG. 6 can also perform a pump operation by applying a DC voltage having the opposite polarity between the electrodes 4b and 4c on the inner and outer surfaces of the solid electrolyte cylindrical body 4a. That is, when a negative electrode is applied to the outer electrode 4c and a positive electrode is applied to the inner electrode 4b, oxygen molecules (O ₂ ) in a gas such as air flowing along the outer surface of the solid electrolyte cylindrical body 4a are solid. It is electrically reduced by the electrolyte to be ionized (O ²⁻ ), and is released again as oxygen molecules (O ₂ ) through the solid electrolyte into the solid electrolyte cylindrical body 4a. In this case, the oxygen partial pressure of the inert gas flowing inside the solid electrolyte cylindrical body 4a is increased and fed to the outside.

  If a gas whose oxygen partial pressure is controlled by such an oxygen pump is supplied, crystal growth, alloying, heat treatment, semiconductor manufacturing process, etc. can be performed in an atmosphere such as an inert gas whose oxygen partial pressure is controlled.

  A gas pump for flowing a gas to be processed that receives a pumping action such as an inert gas in the axial direction through the inside of a solid electrolyte cylindrical body of an ionic conductor is a single circular pipe-shaped solid electrolyte like the oxygen pump of FIG. Use a cylindrical body. A gas to be treated is caused to flow in the axial direction in the internal space of the single solid electrolyte cylindrical body, and an ion conductive pumping action is performed inside and outside the solid electrolyte partition wall while flowing through the solid electrolyte cylindrical body. The gas flow rate that can be processed by such a gas pump is proportional to the contact area between the gas to be processed and the outer surface of the solid electrolyte cylindrical body. Therefore, in order to increase the gas flow rate, it is necessary to increase the contact area between the gas to be processed and the outer surface of the solid electrolyte cylindrical body.

  To that end, it is conceivable to lengthen the solid electrolyte cylindrical body or increase the pipe diameter. In order to effectively use the oxygen ion conductive solid electrolyte, it is necessary to reduce the resistance value of the oxygen pump as much as possible and increase the oxygen permeation ability of the oxygen pump. The resistance value of the oxygen pump is affected by the shape (surface area and thickness) of the solid electrolyte, the electrode film, the lead terminal, and the like. Among these, the shape of the solid electrolyte has a large surface area, and the resistance value decreases as the thickness decreases. That is, when considering a cylindrical body, a shape having a large diameter and length and a small thickness is preferable. However, in view of the ease of manufacturing the solid electrolyte cylindrical body and the strength of the solid electrolyte cylindrical body used in a heated and high temperature holding state, there are limits to the diameter, length, and thickness. In addition, as the pipe diameter increases, the ion conduction reaction of the gas to be processed flowing through the center of the solid electrolyte cylindrical body decreases rapidly, and as a result, the gas to be processed flowing through the center passes through without reaction. In addition, control accuracy such as oxygen partial pressure decreases. For this reason, there is a limit to simply increasing the pipe diameter of the solid electrolyte cylindrical body. Therefore, there is a limit in increasing the contact area between the gas to be treated and the solid electrolyte cylindrical body by the above method. For this reason, the gas flow rate that can be processed substantially effectively by the gas pump is limited, and the application of supplying gas with controlled oxygen partial pressure is limited.

  An object of the present invention is to provide a gas pump having an increased gas flow rate that can be processed substantially effectively with a solid electrolyte cylindrical body having an appropriate diameter.

  In order to achieve the above-mentioned object, the present invention provides a circular solid electrolyte cylindrical body unit that is formed by unitizing a plurality of solid electrolyte cylindrical bodies having different diameters, each having electrodes on both the inner and outer surfaces, in the center. A plurality of concentric circles are arranged at equal intervals in a vertically placed specification in which the lines are substantially vertical, and each solid electrolyte cylindrical body unit is heated by a ring-shaped heating device surrounding the plurality of solid electrolyte cylindrical body units. Features. In addition, a heat storage member that stores heat by being heated by a heating device can be disposed in a space surrounded by a plurality of solid electrolyte cylindrical units.

  Here, as the solid electrolyte cylindrical body, a YSZ (yttrium-stabilized zirconia) zirconia-based oxide ion conductor or a proton conductor solid electrolyte can be applied. The former gas pump using a zirconia solid electrolyte cylindrical body is a so-called oxygen pump. The gas pump using the solid electrolyte cylindrical body of the latter proton conductor is a so-called hydrogen pump and can be applied to a fuel cell manufacturing apparatus or the like. In addition, although a plurality of solid electrolyte cylindrical bodies are desirably circular pipes having different inner diameters in terms of strength and quality, elliptical pipes and polygonal pipes can also be applied depending on applications. A net-like electrode such as platinum is formed on both the inner and outer surfaces of each of the plurality of solid electrolyte cylindrical bodies having different diameters. A DC voltage having a different polarity is applied to the outer surface side electrode and the inner surface side electrode of one solid electrolyte cylindrical body to perform an ion conductive pumping action. Also, a plurality of solid electrolyte cylindrical bodies are concentrically arranged in a multiple manner, and a cylindrical space is formed between the inner and outer solid electrolyte cylindrical bodies adjacent to each other in a concentric manner. The gas is flowed in the axial direction of the solid electrolyte cylindrical body. The gas used here is a gas to be processed for pump operation that is subjected to oxygen partial pressure control, etc., and a secondary gas based on the processing of the gas to be processed (exhaust gas including oxygen molecules generated by processing the gas to be processed) Or high oxygen partial pressure atmospheric gas provided to the gas to be processed for the processing of the gas to be processed). These gases flow in a space formed between a plurality of solid electrolyte cylindrical bodies arranged concentrically and multiply, or a flow path formed between the outer periphery of the solid electrolyte cylindrical body having the maximum diameter and the heating device.

  By flowing the gas to be processed into each of the plurality of solid electrolyte cylindrical units arranged concentrically in this way, the contact area between the gas to be processed and the solid electrolyte cylindrical body is increased, and the pump processing is performed. The amount of gas increases. In addition, a ring-shaped heating device equidistant to a plurality of solid electrolyte cylindrical units uniformly heats each solid electrolyte cylindrical unit, and the temperature difference between the units is reduced. This eliminates the difference in oxygen permeation ability of the solid electrolyte cylindrical unit. Furthermore, each solid electrolyte tubular body unit whose center line is arranged substantially vertically is heated from the outside by a heating device, and from the inside by a heat storage member, so that the solid electrolyte tubular body of each unit is circumferentially Thus, the temperature difference can be reduced and the heating can be performed uniformly, and the control accuracy of the gas to be processed flowing inside each unit can be increased. Thereby, the processing of the same gas to be processed is performed in a plurality of solid electrolyte cylindrical units without individual differences, and control accuracy such as oxygen partial pressure can be improved.

  In the present invention, a plurality of circular solid electrolyte cylinders having the same diameter and the same length having electrodes on both the inner and outer surfaces are placed on concentric circles with each central axis vertical, and the plurality of circular solid electrolyte cylinders Each solid electrolyte cylindrical body is heated by a ring-shaped heating device surrounding the body. In addition, a heat storage member that stores heat by being heated by a heating device can be disposed in a space surrounded by a plurality of solid electrolyte cylindrical bodies.

  In the present invention, each of the plurality of solid electrolyte cylindrical bodies can be composed of an oxide ion conductor. This oxide ion conductor solid electrolyte cylinder is operated by a pump that moves oxygen molecules in the gas to be treated to the secondary gas under the condition of being heated at a predetermined temperature, or oxygen molecules in the secondary gas. An oxygen pump that performs a stable operation by performing a reverse pump operation to move to the gas to be processed is configured.

  According to the gas pump of the present invention, the gas to be processed and the solid electrolyte cylinder are formed by passing the gas to be processed through each of the plurality of solid electrolyte cylinder units and the solid electrolyte cylinders arranged concentrically. The contact area with the body can be increased, and an excellent effect that the amount of gas to be pumped can be increased can be obtained. In addition, by increasing the amount of gas that can be processed by the gas pump, large-capacity, high-capacity equipment with large throughput is applied to manufacturing equipment such as material generation equipment that uses extremely low oxygen partial pressure gas and heat treatment equipment that uses high oxygen partial pressure gas. There are advantages that can be made.

  The outline of the embodiment will be described below with reference to FIGS.

  The oxygen pump shown in FIGS. 1 and 2 uses a plurality of circular solid electrolyte cylindrical units 10 ′ that are unitized by concentrically combining two circular solid electrolyte cylindrical bodies 10 a and 10 b having different diameters. A plurality of solid electrolyte cylinders 10 ′ having the same size are placed on concentric circles at equal intervals with each central axis being vertical. The lower ends of a plurality of circular solid electrolyte cylindrical units 10 ′ vertically arranged are connected to a hollow lower cap 12, and the upper ends of each solid electrolyte cylindrical unit 10 ′ are connected to a hollow upper cap 13. Is done. A heat storage member such as a dummy pipe 15 is installed in a space surrounded by a plurality of solid electrolyte cylindrical units 10 ′ on concentric circles. The upper and lower ends of the dummy pipe 15 are fixed to the caps 12 and 13.

  A ring heater 40 as a heating device is concentrically disposed around a plurality of concentric solid electrolyte cylindrical unit 10 '. The inner and outer two solid electrolyte cylindrical bodies 10a and 10b each have net-like electrodes (not shown) made of platinum on both the inner and outer surfaces. A DC voltage having a different polarity is applied to the inner and outer electrodes from a DC power source.

  In the case of the oxygen pump shown in FIGS. 1 and 2, the cylindrical space between the inner solid electrolyte cylindrical body 10a and the outer solid electrolyte cylindrical body 10b of each of the plurality of solid electrolyte cylindrical unit 10 'is used as the gas G1 to be treated. The primary flow path Mp to flow, and the space between the internal space of the inner solid electrolyte cylindrical body 10a and each solid electrolyte cylindrical body unit 10 'is the secondary flow path Np. Each solid electrolyte cylindrical body unit 10 ′ is placed vertically with the lower cap 12 facing down, and heated by the heater 40 from the surroundings. Since each solid electrolyte cylindrical unit 10 'is equidistant from the heater 40, it is heated uniformly with less heating spots. Further, the dummy pipe 15 in the internal space surrounded by each solid electrolyte cylindrical unit 10 ′ is also heated by the heater 40. The solid electrolyte cylindrical unit 10 ′ around the dummy pipe 15 is heated by the heat storage of the dummy pipe 15. That is, since each of the plurality of solid electrolyte tubular units 107 is heated from both inside and outside, it is heated uniformly with a small temperature difference in the circumferential direction, and the heating efficiency is improved. Can be suppressed.

The operation of the oxygen pump in FIG. 1 will be described. In a state where the heater 40 is energized and each solid electrolyte cylindrical unit 10 ′ is heated to about 700 ° C., the gas G1 to be treated is fed into the flow path hole 14 of the lower cap 12. A DC voltage is applied to the electrodes on the inner and outer surfaces of each solid electrolyte cylindrical body 10a, 10b. The to-be-treated gas G1 fed from the outside to the lower cap 12 flows into the primary passage Mp of each solid electrolyte cylindrical unit 10 ′ almost at the same amount and rises. While the gas to be treated G1 flows through the primary flow path Mp, some of the oxygen molecules (O ₂ ) in the gas flowing along the outer surface of the inner solid electrolyte cylindrical body 10a and the inner surface of the outer solid electrolyte cylindrical body 10b are solid. It is electrically reduced by the electrolyte to be ionized (O ²⁻ ), and is ionically conducted through the solid electrolyte cylindrical bodies 10a and 10b to be discharged into the secondary flow path Np. While the gas to be treated G1 passes through the primary flow path Mp, the oxygen partial pressure decreases to the target value and is exhausted from the primary flow path Mp through the cap 13 as a processed gas. In addition, oxygen molecules released into the secondary flow path Np, which is the external space of each solid electrolyte cylindrical unit 10 ', are exhausted together with the surrounding carrier gas (air). Since the gas to be processed G1 fed to the lower cap 12 passes through the plurality of solid electrolyte cylindrical units 10 ′, the contact area between the gas and the solid electrolyte increases, and the amount of gas to be processed increases. .

  Although the solid electrolyte cylindrical unit 10 ′ of the oxygen pump shown in FIG. 1 is a double cylindrical structure, it may be a double or more multiple cylindrical structure, or only a single solid electrolyte cylindrical body. Structures that are not unitized are also possible. Specific examples thereof are shown in FIGS.

  The oxygen pump shown in FIG. 3 and FIG. 4 is an application of the oxygen pump of FIG. 1, and a plurality of circular solid electrolyte cylinders 11 having the same diameter and the same length are arranged concentrically with their central axes vertical. It is installed in. The lower ends of the plurality of circular solid electrolyte cylinders 11 vertically arranged vertically are connected to the hollow lower cap 12, and the upper ends are connected to the hollow upper cap 13. A dummy pipe 15 as a heat storage member is installed in a space surrounded by a plurality of solid electrolyte cylindrical bodies 11 on concentric circles. The upper and lower ends of the dummy pipe 15 are fixed to the caps 12 and 13. A ring heater (heating device) 40 is installed around the plurality of concentric solid electrolyte cylinders 11.

  In the case of the oxygen pump of FIGS. 3 and 4, the internal space of each of the plurality of solid electrolyte cylindrical bodies 11 is a primary flow path Mp through which the gas to be processed G1 flows, and the space between each solid electrolyte cylindrical body 11 is two. This is the next flow path Np. Each solid electrolyte cylindrical body 11 is placed vertically with the lower cap 12 facing down, and heated by the heater 40 from the surroundings. Since each solid electrolyte cylindrical body 11 is equidistant from the heater 40, it is heated uniformly with less heating spots, and the dummy pipe 15 is also heated by the heater 40. Each solid electrolyte cylindrical body 11 around the dummy pipe 15 is heated by the heat storage of the dummy pipe 15. Also in this case, since each of the plurality of solid electrolyte cylindrical bodies 11 is heated from both inside and outside, the heating efficiency is improved and the power consumption of the heater 40 can be suppressed.

  In a state where each solid electrolyte cylindrical body 11 is heated to about 700 ° C., the gas G1 to be treated is fed to the flow path hole 14 of the lower cap 12. The flow path hole 14 and the primary flow path Mp of each solid electrolyte cylindrical body 11 communicate with each other, and the gas G1 to be treated fed from the outside to the lower cap 12 flows into the primary passage Mp of each solid electrolyte cylindrical body 11. At the same time, it flows in almost the same amount and rises. While the gas to be processed G1 moves up the vertical primary flow path Mp, an ionization reaction of oxygen molecules is performed, and the processed gas enters the hollow upper cap 13 and is finally exhausted. Further, oxygen molecules released into the secondary flow path Np, which is the external space of each solid electrolyte cylindrical body 11, are exhausted together with the surrounding carrier gas. Since the gas to be processed G1 fed to the lower cap 12 passes through the plurality of solid electrolyte cylindrical bodies 11, the contact area between the gas and the solid electrolyte increases, and the amount of gas to be processed increases. In addition, since the plurality of solid electrolyte cylindrical bodies 11 are uniformly heated and the difference in oxygen permeability between solids is eliminated, the control accuracy of the oxygen partial pressure can be improved.

  The gas pump of the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the scope of the claims.

It is a side view including the partial cross section which shows the outline | summary of the gas pump which concerns on this invention. It is sectional drawing which follows the T5-T5 line | wire of FIG. It is a side view including the partial cross section which shows the outline | summary of the gas pump which shows other embodiment. It is sectional drawing which follows the T6-T6 line | wire of FIG. It is a block diagram of the installation using an oxygen pump. It is sectional drawing which shows the outline | summary of an oxygen pump.

Explanation of symbols

10a, 10b Solid electrolyte cylindrical body 10 'Solid electrolyte cylindrical body unit 11 Solid electrolyte cylindrical body 12 Lower cap 13 Upper cap 15 Thermal storage member, dummy pipe

Claims (5)

  A circular solid electrolyte cylindrical unit, which is a unit formed by concentrically combining a plurality of solid electrolyte cylindrical bodies with different diameters, each having electrodes on both the inner and outer sides, is concentric with vertical specifications where each center line is substantially vertical A gas pump characterized in that a plurality of solid electrolyte tubular body units are arranged on the top at equal intervals and each solid electrolyte tubular body unit is heated by a ring-shaped heating device surrounding the plurality of solid electrolyte tubular body units.   The gas pump according to claim 1, wherein a heat storage member that stores heat by being heated by the heating device is disposed in a space surrounded by the plurality of solid electrolyte cylindrical units.   A plurality of circular solid electrolyte cylindrical bodies having the same diameter and the same length having electrodes on both the inner and outer surfaces are placed on concentric circles with each central axis vertical, and a ring shape surrounding the plurality of circular solid electrolyte cylindrical bodies A gas pump, wherein each solid electrolyte cylindrical body is heated by a heating device.   The gas pump according to claim 3, wherein a heat storage member that stores heat by being heated by the heating device is disposed in a space surrounded by the plurality of solid electrolyte cylindrical bodies.   The gas pump according to any one of claims 1 to 4, wherein the solid electrolyte cylindrical body is an oxide ion conductor.

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