WO2023200126A1

WO2023200126A1 - Fuel cell system off-gas catalytic burner and fuel cell device comprising same

Info

Publication number: WO2023200126A1
Application number: PCT/KR2023/003479
Authority: WO
Inventors: 박종수; 최승훈; 이성욱; 오덕규
Original assignee: 주식회사 에코마스터
Priority date: 2022-04-12
Filing date: 2023-03-15
Publication date: 2023-10-19
Also published as: KR20230146245A

Abstract

According to one embodiment of the present invention, disclosed are a fuel cell system OFF-GAS catalytic burner and a fuel cell device comprising same, the fuel cell system OFF-GAS catalytic burner comprising: a first combustion unit including a first combustion catalyst carrier coated with a first combustion catalyst causing a first combustion reaction; and a second combustion unit connected to the first combustion unit and including a second combustion catalyst carrier coated with a second combustion catalyst causing a second combustion reaction.

Description

Fuel cell system OFF-GAS catalytic combustor and fuel cell device including the same

The present invention relates to a fuel cell system OFF-GAS catalytic combustor and a fuel cell device including the same.

A catalytic combustor is a device that generates high-temperature combustion heat by burning combustible gas. The combustion heat generated in this catalytic combustor can be used in a fuel reforming device to produce hydrogen or for heating.

Conventional catalytic combustors are equipped with an igniter to ignite fuel at the beginning of operation, but when an igniter is used, a fire may occur in the fuel pipe or fuel tank when the fuel is ignited.

In addition, the housing of the catalytic combustor is mainly made of stainless steel, which has excellent durability and heat resistance. When stainless steel is used, powder containing iron is generated in a high-temperature oxidizing atmosphere, which blocks the exhaust pipe.

As a result, the pressure inside the catalytic combustor increases and hot spots occur.

Accordingly, there is a problem in that the efficiency of the catalytic combustor is lowered and its lifespan is shortened due to the deterioration of the combustion catalyst.

The problem to be solved according to an embodiment of the present invention includes preventing ignition during combustion of combustible gas in a catalytic combustor and simultaneously preventing catalyst deterioration by making combustion heat distribution uniform.

The technical problem to be achieved by the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned can be clearly understood by those skilled in the art from the description below. There will be.

In order to solve the above problem, a catalytic combustor according to an aspect of the present invention includes a first combustion section including a first combustion catalyst carrier coated with a first combustion catalyst that causes a first combustion reaction, and the first combustion section; It may include a second combustion unit that is connected and includes a second combustion catalyst carrier coated with a second combustion catalyst that causes a second combustion reaction.

In addition, a housing including an accommodation space inside, accommodating the first combustion unit and the second combustion unit, a fuel supply unit connected to one side of the housing and supplying combustible gas to the first combustion unit, and one surface of the housing. It may further include a mixed gas supply part that supplies a mixed gas to the first combustion unit, a heater provided on the outside of the housing to heat the housing, and a heat source supply part that supplies a heat source to the heater.

Here, the first combustion catalyst and the second combustion catalyst may include one or more metals selected from platinum (Pt), palladium (Pd), gold (Au), rhodium (Rh), and ruthenium (Ru). .

Here, the first combustion catalyst carrier and the second combustion catalyst carrier may be formed of a porous ceramic material and may have a honeycomb structure including a plurality of cells partitioned by partition walls.

Here, the first cell density of the first combustion catalyst carrier may be smaller than the second cell density of the second combustion catalyst carrier.

Here, the first porosity of the first combustion catalyst carrier may be smaller than the second porosity of the second combustion catalyst carrier.

Here, the first length of the first combustion catalyst carrier in the direction in which the housing extends may be smaller than the second length of the second combustion catalyst carrier in the direction in which the housing extends.

Here, the first coating amount of the first combustion catalyst coated on the first combustion catalyst carrier may be smaller than the second coating amount of the second combustion catalyst coated on the second combustion catalyst carrier.

Here, the first combustion catalyst carrier and the second combustion catalyst carrier may have different cell densities based on the conditions of the combustible gas.

A fuel cell device including a catalytic combustor according to another aspect of the present invention includes a first combustion unit including a first combustion catalyst carrier coated with a first combustion catalyst that causes a first combustion reaction and connected to the first combustion unit. and a second combustion unit including a second combustion catalyst carrier coated with a second combustion catalyst that causes a second combustion reaction, wherein the first combustion catalyst carrier and the second combustion catalyst carrier have different cell densities. It can be formed as

As described above, according to the embodiments and various aspects of the present invention, the durability of the combustion catalyst can be improved by preventing ignition at the inlet of the catalytic combustor during combustion of combustible gas, and at the same time, deterioration can be prevented by uniform combustion heat distribution. there is.

Additionally, it prevents damage to the catalytic combustor due to rapid heat generation and allows safe combustion of combustible gas.

The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the description or claims of the present invention.

1 is a block diagram showing a fuel cell device including a catalytic combustor according to an embodiment of the present invention.

Figure 2 is a diagram showing a catalytic combustor according to an embodiment of the present invention.

Figure 3 is a diagram showing a combustion catalyst carrier of a catalytic combustor according to an embodiment of the present invention.

Figure 4 is a diagram showing a catalytic combustor according to another embodiment of the present invention.

Hereinafter, the present invention will be described with reference to the attached drawings. However, the present invention may be implemented in various different forms and, therefore, is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts that are not related to the description are omitted, and similar parts are given similar reference numerals throughout the specification.

Throughout the specification, when a part is said to be "connected (connected, contacted, combined)" with another part, this means not only "directly connected" but also "indirectly connected" with another member in between. "Includes cases where it is. Additionally, when a part is said to “include” a certain component, this does not mean that other components are excluded, but that other components can be added, unless specifically stated to the contrary.

The terms used herein are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as “comprise” or “have” are intended to indicate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

One embodiment of the present invention relates to a fuel cell system OFF-GAS catalytic combustor and a fuel cell device including the same.

Referring to FIG. 1, a fuel cell device 1 according to an embodiment of the present invention includes a catalytic combustor 10, a fuel cell 20, and a CO remover 30.

The fuel cell device 1 is a device that converts chemical energy contained in fuel into electrical energy through an electrochemical reaction.

The catalytic combustor 10 and the CO remover 30 are devices included in the fuel reforming device, and are devices that reform hydrocarbon-based fuel into hydrogen in order to supply hydrogen to the fuel cell 20.

The fuel cell 20 is a battery stack that produces electricity through an electrochemical reaction of hydrogen and oxygen supplied from a fuel reforming device.

The catalytic combustor 10 is a device that combusts fuel such as combustible gas by reacting it with a catalyst.

According to one embodiment of the present invention, the catalytic combustor 10 provides heat necessary for a chemical reaction in a fuel reforming device through a combustion reaction of fuel for combustion. For reforming reaction in the fuel reforming device, reforming gas is supplied through the reforming fuel supply line 11. The reforming gas may be a hydrocarbon gas such as LNG, LPG, etc.

The catalytic combustor 10 according to an embodiment of the present invention will be described in detail using FIGS. 2 to 4 below.

Additionally, water is supplied to the fuel reforming device for a reforming reaction with the reforming gas. Water may be introduced into the fuel supply line 11 for reforming.

For the combustion reaction in the catalytic combustor 10, combustion gas is supplied through the combustion fuel supply line 12. The combustion gas, like the reforming gas, may be a hydrocarbon gas such as LPG or LNG. Additionally, a mixed gas is supplied to the catalytic combustor 10 for combustion of combustion gas. The mixed gas can be supplied to the fuel supply line 12 for combustion.

In the CO remover 30, CO inevitably generated by the reforming reaction is removed. Through the CO remover 30, reformed gas with a low CO concentration can be supplied to the fuel cell 20.

Fuel cell 20 includes an anode, a cathode, and an electrolyte disposed between the anode and the cathode. Electricity is generated through an electrochemical reaction between hydrogen supplied to the anode from the fuel reforming device and oxygen contained in the mixed gas supplied to the cathode.

At this time, some of the hydrogen supplied to the anode does not react, and the unreacted hydrogen is discharged to the outside as is. Hydrogen discharged from the anode without reacting is called anode off gas (AOG). AOG includes moisture other than hydrogen, and may also include CO ₂ , N ₂ , etc.

On the other hand, discharging AOG as is brings about the problem of hydrogen waste.

Accordingly, the catalytic combustor 10 of the fuel cell device 1 according to an embodiment of the present invention uses the generated AOG. In this case, hydrocarbon gas, which is a fuel gas, and AOG are supplied together to the catalytic combustor 10.

However, a lot of heat is required to evaporate the moisture contained in AOG in the catalytic combustor (10). This becomes a factor that reduces combustion efficiency in the catalytic combustor (10).

The catalytic combustor 10 of the fuel cell device 1 according to an embodiment of the present invention uses a structure that prevents ignition during the combustion of combustible gas and at the same time prevents catalyst deterioration by uniformly distributing combustion heat. Even if AOG is used in the fuel cell device (1), flammable gas can be burned safely.

The catalytic combustor 10 is a device that combusts fuel such as combustible gas by reacting it with a catalyst. Since the reaction occurs on the surface of the catalyst, the reaction occurs at a lower temperature compared to the flame combustion device of the prior art, and the fuel Even when the concentration is rare, the combustion reaction can be performed stably.

The catalytic combustor 10 according to an embodiment of the present invention relates to a catalytic combustor for a fuel reforming device.

Specifically, by controlling the cell density of the honeycomb structure used as a carrier for the combustion catalyst based on the composition and concentration of the combustible gas (H ₂ , CH ₄ , CO, etc.), catalyst ignition due to combustible gas is prevented. Of course, deterioration of the combustion catalyst can be prevented.

Referring to FIG. 2, the catalytic combustor 10 according to an embodiment of the present invention includes a combustion unit 100, a housing 200, a fuel supply unit 300, a mixed gas supply unit 400, and an outlet 500. do.

When fuel is supplied to the combustion unit 100, the combustible gas (H ₂ , CH ₄ , CO, etc.) contained in the fuel and the mixed gas cause a combustion reaction on the catalyst surface.

In the catalytic combustor 10 according to an embodiment of the present invention, the combustion unit 100 may include a first combustion unit 110, a second combustion unit 120, and a third combustion unit 130.

Accordingly, the catalytic combustor 10 according to an embodiment of the present invention may be formed in a multi-stage configuration so that the combustion unit 100 can sequentially cause combustion reactions.

The first combustion unit 110 includes a first combustion catalyst carrier 111 coated with a first combustion catalyst that causes a first combustion reaction.

Specifically, the first combustion catalyst (not shown) is in a state in which coating has been completed on the first combustion catalyst carrier 111. As shown in FIG. 3 below, the first combustion catalyst (not shown) is coated on the partition wall of the first combustion catalyst carrier 111 and is integrally formed. is formed

The second combustion unit 120 is connected to the first combustion unit and includes a second combustion catalyst carrier 121 coated with a second combustion catalyst that causes a second combustion reaction.

Additionally, the third combustion unit 130 is connected to the second combustion unit and includes a third combustion catalyst carrier 131 coated with a third combustion catalyst that causes a third combustion reaction.

Here, the first combustion catalyst carrier 111 may be formed of a porous ceramic material and may have a honeycomb structure including a plurality of cells 113 partitioned by partition walls 112.

Here, the honeycomb structure refers to a structure in which a ceramic or metal carrier with a honeycomb-shaped channel structure inside is used to reduce pressure reduction and expand the surface area, and the inner wall of the channel inside the catalyst carrier is coated with a material containing a catalyst. do.

Common methods for distinguishing honeycomb structures include cell wall thickness and the number of cells per unit area (cell density). Wall thickness is in mil (1 mil is 1/1000 inch) and cell density is in units per square inch (cpsi: cells per square inch).

Additionally, in one embodiment of the present invention, the porous ceramic material may include, for example, at least one of cordierite, SiC, and aluminum titanate. In addition, materials provided to facilitate fluid flow between each cell can be used.

Additionally, the second combustion catalyst carrier 121 may be formed of a porous ceramic material and may have a honeycomb structure including a plurality of cells 123 partitioned by partition walls 122 .

Additionally, the second combustion catalyst carrier 131 may be formed of a porous ceramic material and may have a honeycomb structure including a plurality of cells 133 partitioned by partition walls 132.

The structures of the first combustion catalyst carrier 111 and the second combustion catalyst carrier 121 will be described in detail in FIG. 3 below.

In the catalytic combustor 10 according to an embodiment of the present invention, the first combustion catalyst and the second combustion catalyst are platinum (Pt), palladium (Pd), gold (Au), rhodium (Rh), and ruthenium (Ru). It may contain one or more metals selected from among.

Additionally, the added third combustion catalyst may include one or more metals selected from platinum (Pt), palladium (Pd), gold (Au), rhodium (Rh), and ruthenium (Ru).

In this specification, the combustion unit 100 is shown as including a first combustion unit 110, a second combustion unit 120, and a third combustion unit 130, but is not limited thereto and includes a combustible gas to be used ( The number and structure of the combustion units 100 can be changed based on the components and concentrations of (H ₂ , CH ₄ , CO, etc.).

In the catalytic combustor 10 according to an embodiment of the present invention, the first combustion catalyst carrier 111 and the second combustion catalyst carrier 121 are formed with different cell densities.

Additionally, the third combustion catalyst carrier 131 may be formed to have a different cell density than the first combustion catalyst carrier 111 and the second combustion catalyst carrier 121.

The housing 200 includes an accommodation space 210 inside and can accommodate the first combustion unit 110 and the second combustion unit 120. Additionally, the third combustion unit 130 may be accommodated.

The fuel supply unit 300 is connected to one side of the housing 200 and supplies combustible gas to the first combustion unit 110.

At this time, as described in FIG. 1, the combustible gas is AOG that is discharged without reacting at the anode, and includes moisture other than hydrogen, and may also include CO ₂ , N ₂ , etc.

The mixed gas supply unit 400 is inserted into one side of the housing 200 and supplies the mixed gas to the first combustion unit 110.

The outlet 500 is connected to the other side of the housing 200 and supplies CO ₂ and generated heat generated as a result of the reaction to the outside.

In the catalytic combustor 10 according to an embodiment of the present invention, a combustion reaction proceeds sequentially from the fuel supply unit 300 to the outlet 500, as shown in the arrow direction at the bottom of FIG. 2.

Specifically, the combustion reaction proceeds first in the first combustion unit 110, and then the combustion reaction proceeds in the second combustion unit 120, and depending on the situation, a third combustion reaction is performed including the third combustion unit 130. A combustion reaction may proceed in unit 130.

Accordingly, first, the rich combustible gas and the mixed gas are burned while passing through the first combustion section 110, and then the lean combustible gas and the mixed gas are burned while passing through the second combustion section 120, and the combustion catalyst is used. By configuring it in multiple stages, catalyst ignition due to combustion of combustible gas can be prevented, and combustion heat distribution can be made uniform to prevent deterioration of the combustion catalyst.

In addition, provided on the outside of the housing 200, it may further include a heater (not shown) that heats the housing and a heat source supply unit (not shown) that supplies a heat source to the heater.

Referring to FIG. 3 , the first combustion catalyst carrier 111 may be formed of a porous ceramic material and may have a honeycomb structure including a plurality of cells 113 partitioned by partition walls 112 .

Additionally, a porous ceramic material may have a structure surrounding the outer peripheral surface 114.

The second combustion catalyst carrier 121 may be formed of a porous ceramic material and may have a honeycomb structure including a plurality of cells 123 partitioned by partition walls 122 .

Additionally, a porous ceramic material may have a structure surrounding the outer peripheral surface 124.

Here, the first combustion catalyst carrier 111 and the second combustion catalyst carrier 121 may be provided in a cylindrical shape as shown in FIG. 3, and may be formed into polygonal pillars in the form of square or hexagonal pillars depending on the shape of the housing 200. It may also be provided in a form.

Specifically, as shown in FIG. 3, the first cell density of the first combustion catalyst carrier 111 may be smaller than the second cell density of the second combustion catalyst carrier 121.

For example, the first cell density of the first combustion catalyst carrier 111 may be 100 cpsi, and the second cell density of the second combustion catalyst carrier 121 may be 200 cpsi.

Additionally, by sequentially increasing, the third cell density of the third combustion catalyst carrier 131 may be 400 cpsi.

Additionally, the first porosity of the first combustion catalyst carrier 111 may be smaller than the second porosity of the second combustion catalyst carrier 121.

Here, porosity refers to the volume ratio of the pores contained in the combustion catalyst carrier to the exclusive volume.

In addition, as shown in FIG. 2, the first length L1 in the direction in which the housing of the first combustion catalyst carrier 111 extends is the second length L1 in the direction in which the housing of the second combustion catalyst carrier 121 extends. It may be less than 2 length (L2).

Additionally, the third length L3 in the direction in which the housing of the third combustion catalyst carrier 131 extends may be smaller than the second length L2.

Additionally, the first coating amount of the first combustion catalyst coated on the first combustion catalyst carrier 111 may be smaller than the second coating amount of the second combustion catalyst coated on the second combustion catalyst carrier 121.

Here, the first combustion catalyst carrier 111 and the second combustion catalyst carrier 121 may have different cell densities based on combustible gas conditions.

The cell density of the first combustion catalyst carrier 111 of the first combustion section 110, where the combustion reaction first occurs, is formed to be small, thereby preventing ignition at the inlet during combustion of combustible gas, thereby improving the durability of the combustion catalyst and reducing combustion heat. Deterioration can be prevented by uniform distribution.

In addition, damage to the catalytic combustor due to rapid heat generation can be prevented and combustible gases can be burned safely.

As shown in Figures 2 and 3, the honeycomb-type combustion catalyst was conventionally used by coating a honeycomb (300 cpsi) with a high cell density with the combustion catalyst, but the catalytic combustor (10) according to an embodiment of the present invention By increasing the cell density sequentially, starting from honeycomb with a low cell density (100 cpsi), it is possible to prevent the rich combustible gas from being burned at the combustion catalyst inlet.

Therefore, all of the rich combustible gas is burned at the combustion catalyst inlet, preventing the temperature of the catalyst surface from rising above 1000°C, thereby suppressing deterioration of the combustion catalyst and improving durability at the same time.

Here, if the hydrogen fuel utilization rate of the solid oxide fuel cell (SOFC) is assumed to be 70%, the anode exhaust gas (AOG) composition is H ₂ (18.9%), CO (2.7%), CO ₂ (14.2%), and Steam. (64.2%) may be.

In this way, the rich combustible gas containing hydrogen is burned in the first combustion section 110, and the lean combustible gas with the hydrogen concentration reduced to 5% or less is burned in the second combustion section 120.

According to one embodiment of the present invention, the temperature of the anode exhaust gas of a solid oxide fuel cell (SOFC) is about 500°C, and the first combustion section 110 burns a rich combustible gas containing hydrogen. ) The temperature at the rear end is 700°C, and due to combustion of lean combustible gas in the second combustion unit 120, the temperature at the rear end of the second combustion unit 120 may be 800°C.

According to another embodiment of the present invention, the first combustion catalyst carrier 111 and the second combustion catalyst carrier 121 can be accommodated inside the housing 200 to enable assembly.

Accordingly, the user can assemble combustion catalyst carriers having various cell density structures based on combustible gas conditions.

For example, the first combustion catalyst carrier 111 and the second combustion catalyst carrier 121 are assembled inside the housing 200, and a fourth combustion catalyst has a cell density greater than that of the third combustion catalyst carrier 131. The carrier 141 can be assembled on the outlet side of the housing 200.

Accordingly, even if the composition of the anode exhaust gas (AOG) changes, it can be used efficiently by replacing the combustion unit without replacing the catalytic combustor itself.

The description of the present invention described above is for illustrative purposes, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical idea or essential features of the present invention. will be. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. For example, each component described as unitary may be implemented in a distributed manner, and similarly, components described as distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the claims described below, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

Claims

a first combustion unit including a first combustion catalyst carrier coated with a first combustion catalyst that causes a first combustion reaction; and

A catalytic combustor connected to the first combustion unit and comprising a second combustion catalyst carrier coated with a second combustion catalyst that causes a second combustion reaction.
According to paragraph 1,

A housing including an accommodation space inside, to accommodate the first combustion unit and the second combustion unit;

a fuel supply unit connected to one side of the housing and supplying combustible gas to the first combustion unit;

a mixed gas supply unit fitted on one side of the housing and supplying a mixed gas to the first combustion unit;

a heater provided outside the housing to heat the housing; and

A catalytic combustor further comprising a heat source supply unit that supplies heat source to the heater.
According to paragraph 1,

The first combustion catalyst and the second combustion catalyst are,

A catalytic combustor comprising one or more metals selected from platinum (Pt), palladium (Pd), gold (Au), rhodium (Rh), and ruthenium (Ru).
According to paragraph 1,

The first combustion catalyst carrier and the second combustion catalyst carrier,

A catalytic combustor, characterized in that it is formed of a porous ceramic material and has a honeycomb structure including a plurality of cells partitioned by partition walls.
According to paragraph 1,

The first cell density of the first combustion catalyst carrier is,

A catalytic combustor, characterized in that the second cell density of the second combustion catalyst carrier is smaller than that of the second combustion catalyst carrier.
According to paragraph 1,

The first porosity of the first combustion catalyst carrier is,

A catalytic combustor, characterized in that the second porosity of the second combustion catalyst carrier is smaller than that of the second combustion catalyst carrier.
According to paragraph 2,

The first length of the first combustion catalyst carrier in the direction in which the housing extends is,

A catalytic combustor, wherein the housing of the second combustion catalyst carrier is smaller than a second length in the direction in which it extends.
According to paragraph 1,

The first coating amount of the first combustion catalyst coated on the first combustion catalyst carrier is,

A catalytic combustor, characterized in that the second coating amount of the second combustion catalyst coated on the second combustion catalyst carrier is smaller than the second coating amount.
According to paragraph 1,

The first combustion catalyst carrier and the second combustion catalyst carrier,

A catalytic combustor characterized in that the cell density is formed differently based on the conditions of the combustible gas.
In a fuel cell device including a catalytic combustor,

The catalytic combustor,

a first combustion unit including a first combustion catalyst carrier coated with a first combustion catalyst that causes a first combustion reaction; and

A second combustion section connected to the first combustion section and including a second combustion catalyst carrier coated with a second combustion catalyst that causes a second combustion reaction,

A fuel cell device, wherein the first combustion catalyst carrier and the second combustion catalyst carrier are formed with different cell densities.