TWI491436B - Production method of exhaust gas purifying reactor - Google Patents

Description

Method for manufacturing exhaust gas purification reactor

The invention relates to an electric catalytic converter, in particular to an exhaust gas purification reaction tube and a method for manufacturing an exhaust gas purification reaction honeycomb.

Fresh and clean air is one of the basic elements of human life. Breathing clean and pollution-free air ensures that human beings can survive in a stable and healthy manner. Although the technological excellence has promoted the rapid development of the economy, the emissions from vehicles and various forestry factories have also caused air pollution, which has a great impact on the air quality of human life. Among them, heavy factories and motor vehicles are the main sources of many pollutants.

Taking motor vehicles as an example, although the emission standards of motor vehicles continue to increase, the number of vehicles is increasing, and the air pollution caused by vehicle emissions is increasing. Generally speaking, the operation of a motor vehicle engine is to release different types of fuel through the internal combustion of the cylinder to release heat energy and generate transmission power; however, in the combustion process, the exhaust gas usually contains nitrogen oxides, carbon monoxide (CO), hydrocarbons. Harmful pollutants such as compounds (HCs), particulate pollutants (PT), smoke, non-methane hydrocarbons (NMHC) and methane (CH ₄ ), which not only form photochemical smog It will also destroy ozone, exacerbate the deterioration of the greenhouse effect and cause acid rain, which will destroy the ecological environment and endanger human health.

Among them, carbon monoxide comes from incomplete combustion of the engine, and its ability to combine with heme to form carbon monoxide hemoglobin (COHb) is 300 times that of heme and oxygen combined with oxygenated heme (HbO ₂ ), so the concentration of carbon monoxide in the air is too high. When it will affect the function of heme transporting oxygen; nitrogen oxides come from the combination of nitrogen and oxygen, mainly in the form of nitric oxide (NO) or nitrogen dioxide (NO ₂ ), which is also easy to combine with heme. It affects human breathing and circulation; in addition, low concentrations of hydrocarbons can irritate the respiratory system, and if the concentration is increased, it will affect the functioning of the central nervous system.

Therefore, regardless of China or the EU, Japan, the United States and other advanced countries, we have set stricter emission standards (such as US BIN5 and Euro 6) for nitrogen oxides (NO _x ) and carbon monoxide (CO). ), emission standards for hydrocarbons such as hydrocarbons (HCs), to control and reduce harmful gas emissions, and encourage manufacturers to manufacture, develop, and introduce products using the latest pollution prevention technologies.

In the conventional oxyfuel combustion exhaust emission control technology, there is no single device or converter that can simultaneously convert nitrogen oxides (NO _x ), carbon monoxide (CO), and hydrocarbons (HCs). Catalytic converters for oxyfuel-burning motor vehicle exhaust systems mostly catalyze only carbon monoxide and hydrocarbons, while for nitrogen oxides, they must rely on other auxiliary devices or systems to convert them. . For example, in addition to the installation of oxidizing catalyst converters to catalyze carbon monoxide and hydrocarbons, most of the exhaust pipes of today's diesel vehicles must be equipped with exhaust gas recirculation (EGR) or nitrogen removal by cylinder spraying. Oxides, newer ones use a selective catalytic reduction (SCR) system to reduce nitrogen oxides.

The selective catalyst reduction system uses ammonia (NH ₃ ) or urea water (urea, CO(NH ₂ ) ₂ ) as a reactant. The urea water is injected into the exhaust pipe through the nozzle to decompose into ammonia gas, and then nitrogen. The oxide is reacted to convert it to nitrogen (N ₂ ) and water (H ₂ O). However, the toxic ammonia gas is not easy to be exposed to the risk of leakage, and the secondary reaction will be caused when the reaction is incomplete. In addition, the selective catalyst reduction system is bulky, and most of them must be matched with precision sensors. control.

In addition, U.S. Patent No. 5,401,372, "Electrochemical catalytic reduction cell for the reduction of NO _x in an O ₂ -containing exhaust emission" discloses a device for separately removing nitrogen oxides, in order to utilize an electrocatalyst reduction reaction, in combination with pentoxide Vanadium pentaoxide (V ₂ O ₅ ) catalyst catalytically assists the conversion of nitrogen oxides into nitrogen; the device must react in a sealed furnace chamber and must be supplied with a power source to cause one of the electrochemical cells in the device to operate. This is not only energy-intensive but also unable to meet the goal of simultaneously removing harmful gases from the exhaust gas.

Therefore, "ELECTROCHEMICAL-CATALYTIC CONVERTER FOR EXHAUST EMISSION CONTROL" in US Patent Application No. 13037693 discloses removal of nitrogen oxides (NO _x ), carbon monoxide (CO), hydrocarbons (HCs), and particulate matter (PM) from exhaust gas. The electrocatalyst converter comprises a battery module, wherein the nitrogen oxides are electrochemically promoted to form nitrogen and oxygen, and the carbon monoxide, hydrocarbons and particles are catalyzed by an oxidation catalyst. Carbon dioxide and water, while achieving the effect of removing a variety of harmful gases at the same time.

However, since the above-mentioned electrocatalyst converter requires a reducing gas system responsible for generating an electromotive force, not only an additional manufacturing cost is increased, but also the circulating reducing gas is heated by the heating unit, and the anode portion is easily caused by the relationship between thermal expansion and contraction. The structure is damaged; at the same time, the converter is not easy to stack a small enough device to facilitate the use of the car; therefore, it still needs to be improved.

The main object of the present invention is to solve the problem that the conventional electrocatalyst converter needs to additionally provide a reducing gas system that generates an electromotive force, resulting in an increase in manufacturing cost, a structure that is easily damaged, and a volume that cannot be effectively reduced.

In order to achieve the above object, the present invention provides a method for producing an exhaust gas purifying reactor, which may be an exhaust gas purifying reaction tube or an exhaust gas purifying reaction honeycomb.

The method for manufacturing the exhaust gas purification reaction tube comprises the following steps:

Providing a tube body made of a solid oxide, the tube body comprising an inner passage, an inner wall surface surrounding the inner passage, and an outer wall surface away from the inner wall surface;

Coating a cathode green layer containing a cathode material on the outer wall surface, and performing a first sintering process to form the cathode green layer to form a cathode layer on the outer wall surface;

Coating an anode green germ layer containing an anode material on the inner wall surface, and performing a second sintering process to form the anode green germ layer to form an anode layer on the inner wall surface;

Providing a reducing environment to the internal passage and closing the tube body to seal the reducing environment to obtain the exhaust gas purifying reaction tube, wherein the surface of the cathode layer serves as a reaction side for purifying an exhaust gas.

The method for manufacturing the exhaust gas purification reaction honeycomb comprises the following steps:

Providing a honeycomb body made of a solid oxide, the honeycomb body comprising a plurality of channels and a partition wall between the channels;

Defining the passage includes a plurality of first conduits for exhaust gas passage and a plurality of second conduits to be closed, the first conduits being adjacent to the second conduits;

a first inner wall surface of the first pipe is coated with a cathode green layer containing a cathode material, and a first sintering process is performed to form the cathode green layer to form a cathode layer on the first inner wall surface;

A second inner wall surface of the second pipe is coated with an anode green layer containing an anode material, and a second sintering process is performed to form the anode green layer to form an anode layer on the second inner wall surface. The spacer wall is between the anode layer and the cathode layer;

Providing a reducing environment to the second pipe and closing the second pipe to seal the reducing environment to obtain the exhaust gas purifying reaction honeycomb, wherein the surface of the cathode layer exposed to the first pipe is used as a purification gas Reaction side.

In this way, the present invention has at least the following advantages by preparing the exhaust gas purification reaction tube and preparing the exhaust gas purification reaction honeycomb:

1. The invention does not need to additionally provide a reducing gas system, that is, the cathode layer can purify an exhaust gas, reduce the production cost, and avoid the problem that the structure is easily damaged.

2. The invention can effectively reduce the overall volume and achieve the purifying effect because the reducing gas system is not required to be provided, and can be disposed in the exhaust pipe of the vehicle engine to eliminate harmful substances in the oxyfuel combustion exhaust gas discharged by the engine and reduce air. Pollution.

The detailed description and technical content of the present invention will now be described as follows:

The present invention provides a method for manufacturing an exhaust gas purification reactor, which may be an exhaust gas purification reaction tube or an exhaust gas purification reaction honeycomb, which will be respectively described by a first embodiment and a second embodiment. An exhaust gas purification reaction tube and a method of manufacturing the exhaust gas purification reaction honeycomb.

Please refer to FIG. 1A to FIG. 1D , which are schematic diagrams of a manufacturing process according to a first embodiment of the present invention. The method for manufacturing the exhaust gas purification reaction tube comprises the following steps:

Step 1: As shown in FIG. 1A, a tube body 10 made of a solid oxide may be provided. The solid oxide may be a fluorite structure metal oxide, a perovskite structure metal oxide or the like, for example, a fluorite structure. Yttrium-stabilized zirconia (YSZ), stabilized zirconia, fluorite-doped yttrium oxide-doped ceria (GDC), doped yttrium oxide, perovskite structure a strontium/magnesium-doped lanthanum gallate (LSGM), doped with lanthanum gallate, wherein the tube 10 formed of zirconia is used, the tube 10 comprising an internal passage 11, a first port 14 , a second port 15 , an inner wall surface 12 , and an outer wall surface 13 . The inner channel 11 is located between the first port 14 and the second port 15 to communicate with the first port. The port 14 and the second port 15 surround the inner passage 11 and the outer wall surface 13 is away from the inner wall surface 12.

Step 2: As shown in FIG. 1B, a cathode green layer containing a cathode material is coated on the outer wall surface 13 and a first sintering process is performed to form the cathode green germ layer to form a cathode on the outer wall surface 13. Layer 20; the cathode material may be a perovskite structure metal oxide, a fluorite structure metal oxide, a metal-added perovskite structure metal oxide or a metal-added fluorite structure metal oxide, for example: a perovskite structure a combination of samarium cobalt copper oxide, lanthanum manganese copper oxide, samarium cobalt copper oxide and yttrium oxide doped yttrium oxide, a combination of lanthanum manganese copper oxide and yttrium oxide doped yttrium oxide, and silver added Combination of samarium cobalt copper oxide, silver-added lanthanum-copper oxide, silver-added samarium-cobalt-copper oxide and yttrium-doped yttrium oxide, silver-doped lanthanum-copper oxide and yttrium oxide doping The combination of cerium oxide, and the purpose of the first sintering operation is to degrease and sinter the cathode material to obtain the cathode layer 20. The temperature rising and cooling steps and the number of times used can be adjusted according to the selection of the cathode material.

In this embodiment, the cathode material layer is a cathode material containing a combination of lanthanum manganese copper oxide and lanthanum oxide-doped cerium oxide. The first port 14 and the second port are first described. 15 is sealed with a tape, and then the fluorite-structured cerium oxide-doped cerium oxide is applied to the outer wall surface 13 by dipping, after which the tape is removed and dried in an oven at 50 ° C for 6 hours. Then, heat treatment is carried out at a heating rate of 5 ° C per minute, from room temperature to 600 ° C, holding temperature for 2 hours, then rising to 900 ° C, holding temperature for 2 hours, then rising to 1200 ° C, holding temperature 4 After the hour, the temperature is lowered back to the room temperature at the same rate and the temperature holding time, and then the first port 14 and the second port 15 are closed and the impregnation is applied to coat the same surface. Oxide, and dried in the oven at 50 ° C for 6 hours, followed by heat treatment at a temperature increase rate of 5 ° C per minute, from room temperature to 300 ° C, holding temperature for 2 hours, and then rising to 600 ° C Hold the temperature for 2 hours, then increase to 900 ° C, hold the temperature for 4 hours, and then return to room temperature at the same rate and holding temperature to form the cathode. Layer 20.

Step 3: As shown in FIG. 1C, an anode green layer containing an anode material is coated on the inner wall surface 12, and a second sintering process is performed to form the anode green layer to form an anode on the inner wall surface 12. Layer 30; the anode material may be fluorite metal oxides, perovskite structure metal oxides, fluorite structure metal oxides, metal addition perovskite structure metal oxides or metal additions Stone structure metal oxides such as nickel and yttria stabilized zirconia cermets (Ni-YSZ cermet).

In this embodiment, the anode material of the anode green layer containing nickel oxide and yttria-stabilized zirconia cermet is exemplified, and the slurry made of the anode material is first along the inner wall surface 12 Pour in, and let the excess slurry naturally slide down and air dry, then carry out the second sintering operation, dry in the oven at 50 ° C for 6 hours, and then heat treatment at a heating rate of 5 ° C per minute, from the chamber The temperature rises to 300 ° C, the temperature is held for 2 hours, then rises to 600 ° C, the temperature is held for 2 hours, then rises to 900 ° C, the temperature is held for 4 hours, and then returned to room temperature at the same rate and holding time. The purpose of the second sintering operation is the same as that of the first sintering operation, and will not be described here. However, in particular, since the zirconia cermet is stabilized by using nickel oxide and yttria as the anode material, it is necessary to The nickel oxide is reduced to nickel, so the anode green germ layer and the tube body 10 are placed in a quartz tube and hydrogen gas is introduced, and a heat treatment is performed at a temperature of 5 ° C per minute, and the temperature is maintained at 400 ° C for 8 hours. The anode is made without destroying the cathode layer 20 Layer is made of nickel oxide and yttria-stabilized zirconia cermet is reduced to nickel and yttria-stabilized zirconia cermet, thus forming the anode layer 30.

Step 4: As shown in FIG. 1D, a reducing environment 111 is provided to the internal passage 11 and the tube 10 is closed to seal the reducing environment 111 to obtain the exhaust gas purifying reaction tube; in this embodiment, A reducing substance 112 is filled in the internal passage 11, and the reducing substance 112 may be a reducing atmosphere, and may be a reducing solid such as graphite powder, carbon black, or a reducing liquid such as ammonia water or a reducing gas. , for example, methane, hydrogen, etc., and the reducing agent 112 is enclosed in the internal passage 11 by a colloid 113 to form the reducing environment 111. The colloid 113 is a ceramic glue, which is resistant to high temperature, and The coefficient of thermal expansion is similar to that of the tube body 10. The common component of the colloid 113 is alumina and yttrium oxide. Thus, the preparation of the exhaust gas purification reaction tube is completed, and the surface of the cathode layer 20 is exposed to the outside as a purification gas 40. On the reaction side, the reducing environment 111 causes an electromotive force between the anode layer 30 and the cathode layer 20 to drive the cathode layer 20 and the exhaust gas 40 to purify the catalytic decomposition of nitrogen oxides in the exhaust gas 40. . It should be further noted that the reducing material 112 may not be filled in the internal passage 11, and the internal passage 11 is directly sealed by the colloid 113, and the air pressure of the internal passage 11 is less than 1 atmosphere, such as forming a vacuum state. The reducing environment 111 can also be formed.

Please refer to FIG. 2A to FIG. 2D , which are schematic diagrams of a manufacturing process according to a second embodiment of the present invention. In the second embodiment, the method for manufacturing the exhaust gas purification reaction honeycomb includes the following steps:

Step A: As shown in Fig. 2A, a honeycomb body 50 made of a solid oxide is provided. The honeycomb body 50 includes a plurality of channels 51 and a partition wall 52 between the channels 51. The partition walls 52 are arranged adjacent to each other, and the cross section of the passage 51 is illustrated as a square. However, the cross-section of the passage 51 is not limited thereto, and may be a circular or hexagonal shape to form a closely packed structure.

Step B: Defining the passage 51 includes a plurality of first conduits 511 for passing an exhaust gas 80 (shown in FIG. 2D) and a plurality of second conduits 513 to be closed, the first conduit 511 being adjacent to the second conduit 513 Here, it is a preferred arrangement to form an adjacent and staggered arrangement between the first pipe 511 and the second pipe 513, but is not limited thereto.

Step C: As shown in FIG. 2B, a first inner wall surface 512 of the first pipe 511 is coated with a cathode green layer containing a cathode material, and a first sintering process is performed to form the cathode green germ layer. a cathode layer 60 on the first inner wall surface 512; in step C of the second embodiment, in contrast to step 2 of the first embodiment, step C is characterized in that the first step is to use a silicone gasket The second pipe 513 is first closed, and the cathode green layer is coated on the first inner wall surface 512. The coating method used for the cathode material and the first sintering process performed are the same as the above step 2. This description will not be repeated here, and the cathode layer 60 is obtained accordingly.

Step D: As shown in FIG. 2C, a second inner wall surface 514 of the second pipe 513 is coated with an anode green layer containing an anode material, and a second sintering process is performed to form the anode green germ layer. An anode layer 70 on the second inner wall surface 514 is disposed between the anode layer 70 and the cathode layer 60. Similarly, in the step D of the second embodiment, the steps of the first embodiment are the same as those of the first embodiment. In contrast, step D is characterized in that the silicone gasket that closes the second pipe 513 is removed, and the first pipe 511 is closed to be coated, and the anode material is coated in the second manner by dipping. On the wall surface 514, the silicone gasket is then removed from the first pipe 511, and the anode greening layer is formed on the second inner wall surface 514 by the same second sintering process and reduction procedure as in the third step. The anode layer 70.

Step E: As shown in FIG. 2D, the second pipe 513 is provided with a reducing environment 515 and the second pipe 513 is closed to seal the reducing environment 515 to obtain the exhaust gas purification reaction honeycomb. Similarly, step E and In the step S4, the reducing environment 515, the reducing material 516 and the colloid 517 are formed in the same manner. Only the step E is characterized in that the reducing environment 515 is formed in the second pipe 513. The first pipe 511 of the exhaust gas purification reaction honeycomb is for the exhaust gas 80 to flow, and the second pipe 513 is spaced apart from the first pipe 511 by the partition wall 52, and therefore, from the second pipe 513 through the partition wall 52 to The first pipe 511 sequentially forms the reducing environment 515, the anode layer 70, the partition wall 52 which is a solid oxide, and the layered structure of the cathode layer 60, and is exposed to the first pipe 511. The surface of the cathode layer 60 serves as a reaction side for purifying the exhaust gas 80, and a catalytic decomposition reaction for purifying nitrogen oxides in the exhaust gas 80 is performed.

In summary, since the present invention prepares the exhaust gas purification reaction tube and prepares the exhaust gas purification reaction honeycomb, the invention does not need to additionally provide a reducing gas system, that is, the cathode layer can purify an exhaust gas, thereby reducing the production cost. And avoiding the problem that the structure is easily damaged. Moreover, since the present invention does not need to provide the reducing gas system, the effect of effectively reducing the overall volume and achieving the purification effect can be set in the exhaust pipe of the vehicle engine to eliminate the engine discharge. Oxygen-enriched combustion of harmful substances in the exhaust gas, reducing air pollution, so the present invention is extremely progressive and meets the requirements of the invention patent application, 提出 apply in accordance with the law, the prayer bureau will grant patents as soon as possible, and it is really sensible.

The present invention has been described in detail above, but the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the scope of the invention. That is, the equivalent changes and modifications made by the scope of the present application should remain within the scope of the patent of the present invention.

10. . . Tube body

11. . . Internal channel

111. . . Reducing environment

112. . . Reducer

113. . . colloid

12. . . Inner wall

13. . . Outer wall

14. . . First port

15. . . Second port

20. . . Cathode layer

30. . . Anode layer

40. . . Exhaust gas

50. . . Honeycomb body

51. . . aisle

511. . . First pipe

512. . . First inner wall

513. . . Second pipe

514. . . Second inner wall

515. . . Reducing environment

516. . . Reducer

517. . . colloid

52. . . Partition wall

60. . . Cathode layer

70. . . Anode layer

80. . . Exhaust gas

1A to 1D are schematic views showing a manufacturing process of a first embodiment of the present invention.

2A to 2D are schematic views showing a manufacturing process of a second embodiment of the present invention.

10. . . Tube body

111. . . Reducing environment

112. . . Reducer

113. . . colloid

12. . . Inner wall

13. . . Outer wall

20. . . Cathode layer

30. . . Anode layer

40. . . Exhaust gas

Claims (14)

A method for manufacturing an exhaust gas purification reaction tube, comprising the steps of:
Providing a tube body made of a solid oxide, the tube body comprising an inner passage, an inner wall surface surrounding the inner passage, and an outer wall surface away from the inner wall surface;
Coating a cathode green layer containing a cathode material on the outer wall surface, and performing a first sintering process to form the cathode green layer to form a cathode layer on the outer wall surface;
Coating an anode green germ layer containing an anode material on the inner wall surface, and performing a second sintering process to form the anode green layer to form an anode layer on the inner wall surface; and providing a reduction property to the inner passage The exhaust gas purification reaction tube is obtained by sealing the tube body to seal the reducing environment, wherein the surface of the cathode layer serves as a reaction side for purifying an exhaust gas. The method for producing an exhaust gas purification reaction tube according to claim 1, wherein the method for forming the reducing environment comprises the steps of:
Filling the interior passage with a reducing material; and sealing the tube body with a colloid such that the reducing material is located in the internal passage to form the reducing environment. The method for producing an exhaust gas purification reaction tube according to claim 2, wherein the reducing material is a reducing atmosphere, and the reducing atmosphere is a group selected from the group consisting of a reducing solid, a reducing liquid, and a reducing gas. group. The method for producing an exhaust gas purification reaction tube according to claim 1, wherein the method for forming the reducing environment comprises the steps of:
Forming a gas pressure of less than one atmosphere at the inner passage; and sealing the tube with a gel to form the reducing environment. The method for producing an exhaust gas purifying reaction tube according to claim 1, wherein the solid oxide is selected from the group consisting of fluorite structure metal oxides, perovskite structure metal oxides, and combinations thereof. The method for producing an exhaust gas purification reaction tube according to claim 1, wherein the cathode material is selected from the group consisting of a perovskite structure metal oxide, a fluorite structure metal oxide, a metal-added perovskite structure metal oxide, A group of metal-added fluorite structure metal oxides and combinations thereof. The method for producing an exhaust gas purification reaction tube according to claim 1, wherein the anode material is selected from the group consisting of metal and fluorite structure metal oxides, gold oxide, perovskite structure metal oxide, and fluorite structure metal oxide. A group consisting of a metal-added perovskite structure metal oxide, a metal-added fluorite structure metal oxide, and combinations thereof. A method for manufacturing an exhaust gas purification reaction honeycomb comprises the following steps:
Providing a honeycomb body made of a solid oxide, the honeycomb body comprising a plurality of channels and a partition wall between the channels;
Defining the passage includes a plurality of first conduits for exhaust gas passage and a plurality of second conduits to be closed, the first conduits being adjacent to the second conduits;
a first inner wall surface of the first pipe is coated with a cathode green layer containing a cathode material, and a first sintering process is performed to form the cathode green layer to form a cathode layer on the first inner wall surface;
A second inner wall surface of the second pipe is coated with an anode green layer containing an anode material, and a second sintering process is performed to form the anode green layer to form an anode layer on the second inner wall surface. The partition wall is located between the anode layer and the cathode layer; and provides a reducing environment to the second pipe and encloses the second pipe to seal the reducing environment to obtain the exhaust gas purification reaction honeycomb, wherein the exposed The surface of the cathode layer of the first conduit serves as a reaction side for purifying an exhaust gas. The method for producing an exhaust gas purification reaction honeycomb according to claim 8, wherein the method for forming the reducing environment comprises the following steps:
Filling a second conduit with a reducing material; and sealing the second conduit with a colloid to cause the reducing material to be located in the second conduit to form the reducing environment. The method for producing an exhaust gas purification reaction honeycomb according to claim 9, wherein the reducing material is a reducing atmosphere, and the reducing atmosphere is a group selected from the group consisting of a reducing solid, a reducing liquid, and a reducing gas. group. The method for producing an exhaust gas purification reaction honeycomb according to claim 8, wherein the method for forming the reducing environment comprises the following steps:
Forming a gas pressure of less than one atmosphere at the second conduit; and closing the second conduit with a gel, the second conduit forming the reducing environment. The method for producing an exhaust gas purification reaction honeycomb according to claim 8, wherein the solid oxide is selected from the group consisting of fluorite structure metal oxides, perovskite structure metal oxides, and combinations thereof. The method for producing an exhaust gas purification reaction honeycomb according to claim 8, wherein the cathode material is selected from the group consisting of a perovskite structure metal oxide, a fluorite structure metal oxide, a metal-added perovskite structure metal oxide, A group of metal-added fluorite structure metal oxides and combinations thereof. The method for producing an exhaust gas purification reaction honeycomb according to claim 8, wherein the anode material is selected from the group consisting of metal and fluorite structure metal oxides, gold oxide, perovskite structure metal oxide, and fluorite structure metal oxide. A group consisting of a metal-added perovskite structure metal oxide, a metal-added fluorite structure metal oxide, and combinations thereof.