KR102623977B1 - Methane oxidation catalyst regeneration device and regeneration method - Google Patents

Abstract

The present invention relates to a regeneration device and method for a methane oxidation catalyst that oxidizes methane, and in particular to reducing PdO formed in the methane oxidation catalyst by injecting regeneration gas into the reactor while the reactor equipped with the methane oxidation catalyst is closed. It is configured to regenerate the entire methane oxidation catalyst inside the reactor or select and regenerate some of the methane oxidation catalyst.
In order to achieve the above object, the methane oxidation catalyst regeneration device according to the present invention includes a reactor equipped with a methane oxidation catalyst, a regeneration gas supply line that supplies regeneration gas to the reactor, and a regeneration gas supply line branched from the regeneration gas supply line to It extends upstream of the methane oxidation catalyst and includes a regeneration gas branch pipe that sprays regeneration gas toward the methane oxidation catalyst. The technical feature is that the regeneration gas sprayed from the regeneration gas branch pipe reduces PdO formed in the methane oxidation catalyst. , The methane oxidation catalyst regeneration method is technically characterized by including the step of closing the reactor equipped with the methane oxidation catalyst and the step of reducing PdO by injecting regeneration gas upstream of the methane oxidation catalyst.

Description

Methane oxidation catalyst regeneration device and regeneration method}

The present invention relates to a regeneration device and method for a methane oxidation catalyst that oxidizes methane, and in particular to reducing PdO formed in the methane oxidation catalyst by injecting regeneration gas into the reactor while the reactor equipped with the methane oxidation catalyst is closed. It is configured to regenerate the entire methane oxidation catalyst inside the reactor or select and regenerate some of the methane oxidation catalyst.

Compared to existing fuels, natural gas fuel is attracting attention as an eco-friendly fuel with very low emissions of air pollutants and global warming gases such as carbon dioxide, sulfur oxides, nitrogen oxides, and particulate matter (PM). Because of these advantages, the use of engines fueled by natural gas is increasing in ships and automobiles.

However, natural gas contains methane as its main component, and methane has a strong carbon-hydrogen bond and exists in a fairly stable state. Therefore, when it is discharged without being completely consumed by the engine, it is not naturally oxidized under the exhaust gas temperature conditions and causes untreated It is discharged directly into the atmosphere.

Meanwhile, methane (CH4) is a global warming substance that is 28 to 86 times more potent than an equivalent amount of carbon dioxide (CO2). In order to solve the problem of global warming, the amount of methane emitted from exhaust gases must be reduced, and recently the International Maritime Organization (IMO) and the European Union (EU) have strengthened regulations to reduce GHG (global warming gases, green house gases) emissions. Accordingly, regulations on GHG emissions such as carbon dioxide (CO2) and carbon taxes are being discussed, and technologies that do not emit methane into the atmosphere are required.

In response to these demands, various studies have been conducted on methods to efficiently purify exhaust gases from dual fuel engines (DF engines), which are a major cause of environmental pollution, especially methane contained in large amounts in exhaust gases. is in progress.

As a method of efficiently removing methane, a technology using a catalyst to oxidize methane is being developed.

Recently, catalysts containing precious metals supported on oxide carriers such as alumina and palladium or platinum supported on alumina have become widely known, and are used in fuel-lean atmospheres to improve fuel efficiency in ships and automobiles equipped with compressed natural gas engines. A technology using an oxidation catalyst mixed with palladium and platinum is being developed to purify methane contained in exhaust gas when the engine is operated in lean-burn.

However, in the case of palladium, when oxygen is adsorbed on the catalyst, PdO (Palladium Oxidation) occurs, and the oxidation performance of methane is reduced by PdO.

Therefore, in order to remove methane using a palladium-based methane oxidation catalyst, there is an urgent need to develop catalyst regeneration technology to reduce PdO generated in the methane oxidation catalyst, especially when the engine is operated in a fuel lean atmosphere (lean-burn). There is a problem in that excess oxygen reacts with the methane oxidation catalyst, causing a significant increase in the generation of PdO.

Republic of Korea Patent No. 10-1909303 Republic of Korea Patent Publication No. 10-2016-0112179 Republic of Korea Patent No. 10-1598390

The present invention was invented to solve the problems of the prior art as described above, and the reactor equipped with the methane oxidation catalyst is closed and the regeneration gas is injected into the reactor to reduce the PdO formed in the methane oxidation catalyst. The purpose is to provide a methane oxidation catalyst regeneration device and method that can regenerate the entire internal methane oxidation catalyst or select a portion of the methane oxidation catalyst.

In order to achieve the above object, the methane oxidation catalyst regeneration device according to the present invention includes a reactor equipped with a methane oxidation catalyst, a regeneration gas supply line that supplies regeneration gas to the reactor, and a regeneration gas supply line branched from the regeneration gas supply line to It extends upstream of the methane oxidation catalyst and includes a regeneration gas branch pipe for spraying regeneration gas toward the methane oxidation catalyst, and its technical feature is that PdO is reduced by the regeneration gas sprayed from the regeneration gas branch pipe.

In addition, according to a preferred embodiment of the present invention, a plurality of methane oxidation catalysts are arranged at intervals along the direction of exhaust gas inside the reactor, and a regeneration gas branch pipe is extended for each methane oxidation catalyst.

Additionally, according to a preferred embodiment of the present invention, a valve is mounted on the regeneration gas branch pipe to control the supply of regeneration gas from the regeneration gas supply line to the regeneration gas branch pipe.

Additionally, according to a preferred embodiment of the present invention, a valve is installed in the regeneration gas supply line to control the supply of regeneration gas to the regeneration gas supply line.

The methane oxidation catalyst regeneration method according to the present invention for achieving the above object includes the steps of closing the reactor equipped with the methane oxidation catalyst and injecting regeneration gas upstream of the methane oxidation catalyst to reduce PdO. It is a technical feature.

In addition, according to a preferred embodiment of the present invention, the method further includes selectively performing regeneration of the methane oxidation catalyst by supplying regeneration gas to only some of the methane oxidation catalysts among the plurality of methane oxidation catalysts mounted inside the reactor.

In addition, according to a preferred embodiment of the present invention, the method further includes the step of supplying regeneration gas to each of a plurality of methane oxidation catalysts mounted inside the reactor to regenerate all methane oxidation catalysts.

As described above, the methane oxidation catalyst regeneration device and regeneration method according to the present invention can minimize methane emitted into the atmosphere by reducing PdO generated in the methane oxidation catalyst by injecting regeneration gas into the reactor to improve methane oxidation performance. It is structured so that the methane oxidation catalyst can be reduced by injection of regeneration gas, and has the advantage of being structurally simple and having a large regeneration effect.

In addition, the methane oxidation catalyst regeneration device and regeneration method according to the present invention are configured to regenerate all methane oxidation catalysts mounted inside the reactor at once or to selectively regenerate methane oxidation catalysts in which PdO is severely generated, thereby improving the regeneration efficiency of the methane oxidation catalyst. There is an advantage in that it can be increased.

1 is a cross-sectional view showing a methane oxidation catalyst reactor according to an example of the present invention,
Figure 2 is a conceptual diagram showing the relationship between spraying regeneration gas toward the methane oxidation catalyst shown in Figure 1.
Figure 3 is a cross-sectional view showing a methane oxidation catalyst reactor according to another example of the present invention,
Figure 4 is a conceptual diagram showing the relationship between spraying regeneration gas toward the methane oxidation catalyst shown in Figure 1.

Below, preferred embodiments of the methane oxidation catalyst regeneration device and regeneration method according to the present invention will be described in detail with reference to the attached drawings.

In the drawings, FIG. 1 is a cross-sectional view showing a methane oxidation catalyst reactor according to an example of the present invention, and FIG. 2 is a conceptual diagram showing the relationship of spraying regeneration gas toward the methane oxidation catalyst shown in FIG. 1. And Figure 3 is a cross-sectional view showing a methane oxidation catalyst reactor according to another example of the present invention, and Figure 4 is a conceptual diagram showing the relationship of spraying regeneration gas toward the methane oxidation catalyst shown in Figure 1.

As shown in FIGS. 1 and 2, the front exhaust pipe 11F extending from the engine 10 is connected to the reactor 110, and the rear exhaust pipe 11B extending from the reactor 110 is connected to the atmosphere or to the economizer. It is extended.

Therefore, the exhaust gas generated from the engine 10 flows into the reactor 110 along the front exhaust pipe 11F.

The reactor 110 has an inlet 111 connected to the front exhaust pipe 11F at the bottom, and an outlet 113 connected to the rear exhaust pipe 11B at the top of the reactor 110, and the inlet 111 ) is equipped with an inlet valve (111V) and an outlet valve (113V) is installed at the outlet (113).

In the reactor 110 configured as described above, when the inlet valve (111V) and the outlet valve (113V) are closed, the inside of the reactor 110 is closed, and when the inlet valve (111V) and the outlet valve (113V) are opened, the engine 10 The exhaust gas generated from ) flows into the reactor 110 along the front exhaust pipe 11F and is then exhausted to the outside of the reactor 110 along the rear exhaust pipe 11B.

Meanwhile, a methane oxidation catalyst (MOC) 120 is installed inside the reactor 110. As an example, as a plurality of methane oxidation catalysts 120 are installed inside the reactor 110 at intervals along the flow direction of the exhaust gas, the exhaust gas flowing into the inlet 111 flows toward the outlet 113 and produces multiple methane oxidation catalysts 120. It sequentially passes through the methane oxidation catalyst (120).

The methane oxidation catalyst 120 is a palladium (Pd)-based catalyst that oxidizes methane (CH4) in exhaust gas into water and carbon dioxide (CO2) through the chemical reaction below.

Therefore, methane flowing into the reactor 110 passes through the methane oxidation catalyst 120 and is oxidized into water and carbon dioxide as shown in Chemical Formula 1 above, and then is exhausted through the rear exhaust pipe 11B.

Methane is a global warming gas that is 28 times stronger than carbon dioxide. By oxidizing methane and exhausting carbon dioxide, it can reduce global warming compared to methane emissions.

Meanwhile, while methane is oxidized, the methane oxidation catalyst 120 is also oxidized, and PdO, an oxidizing material, is formed on the catalyst surface. When PdO, an oxidizing material, is formed on the catalyst surface, contact with methane is blocked, thereby reducing the efficiency of the catalytic reaction, that is, the oxidation of methane.

The purpose of the present invention is to regenerate the methane oxidation catalyst (120) so as to improve the decline in methane oxidation performance that occurs when PdO, an oxidizing material, is formed in the methane oxidation catalyst (120), and to realize the purpose. For this purpose, regeneration gas is injected into the reactor 110.

The methane oxidation catalyst regeneration device according to the present invention for regenerating the methane oxidation catalyst 120 by injecting regeneration gas into the reactor 110 extends into the interior of the reactor 110 and regenerates the methane oxidation catalyst in the flow direction of the exhaust gas. To regenerate among the regeneration gas branch pipes 131 located upstream of (120) and spraying regeneration gas to the methane oxidation catalyst 120, and a plurality of methane oxidation catalysts 120 mounted inside the reactor 110. Valves (131V) mounted on each of the regeneration gas branch pipes (131) to select and regenerate the methane oxidation catalyst (120), and regeneration gas located outside the reactor (110) and connected to the regeneration gas branch pipes (131). Includes a supply line 130.

In the methane oxidation catalyst regeneration device configured as described above, the pressure applied to the regeneration gas supply line 130 is set higher than the pressure inside the closed reactor 110, so that the valve 131V installed in the regeneration gas branch pipe 131 When opened, the regeneration gas flows into the reactor 110 through the regeneration gas supply line 130 and the regeneration gas branch pipe 131 due to the pressure difference. At this time, the regeneration gas injected from the regeneration gas branch pipe 131 flows into the opposing methane oxidation catalyst 120.

On the other hand, the regeneration gas can be composed of any one of N2, H2, and HC that can reduce PdO, or a gas mixed at a specific mixing ratio, and the regeneration gas reduces the PdO generated in the methane oxidation catalyst (120). to regenerate the methane oxidation catalyst (120).

In this way, the methane oxidation catalyst 120 is regenerated through the regeneration operation of reducing PdO in the methane oxidation catalyst 120, and then the inlet valve 111V and the outlet valve 113V are opened to allow methane in the exhaust gas to flow into the reactor 110. ) When introduced inside, the oxidation performance of methane is improved as shown in the reaction formula (1).

Meanwhile, the methane oxidation catalyst regeneration device described above is a regeneration gas branch pipe to regenerate some of the methane oxidation catalysts or the entire methane oxidation catalyst as shown in FIG. 2 among the methane oxidation catalysts 120 installed inside the reactor 110. Although the valve 131V is installed in 131, it can be configured to collectively regenerate all the methane oxidation catalysts 120 installed inside the reactor 110, as shown in FIGS. 3 and 4.

In this case, as shown in FIG. 3, the regeneration gas branch pipe 131 branches off from the regeneration gas supply line 130, and a valve (130V) is installed on the regeneration gas supply line 130.

Therefore, when the valve (130V) installed in the regeneration gas supply line 130 is opened, the regeneration gas flows into the reactor 110 through the regeneration gas branch pipe 131 branched from the regeneration gas supply line 130, and each methane oxidation The regeneration gas injected through the regeneration gas branch pipe 131 located upstream in response to the catalyst 120 flows into each methane oxidation catalyst 120 to regenerate the entire methane oxidation catalyst 120 inside the reactor 110 at once. It can also be configured to do so.

10: engine
11F, 11B: Exhaust pipe
110: reactor
111: inlet
111V: Inlet valve
113: outlet
113V: outlet valve
120: Methane oxidation catalyst (MOC)
130: Regeneration gas supply line
130V: valve
131: Regeneration gas branch pipe
131V: valve

Claims (7)

A reactor equipped with a methane oxidation catalyst,
A regeneration gas supply line that supplies regeneration gas to the reactor,
It branches off from the regeneration gas supply line and extends upstream of the methane oxidation catalyst inside the reactor, and includes a regeneration gas branch pipe that sprays regeneration gas toward the methane oxidation catalyst,
A methane oxidation catalyst regeneration device characterized in that the regeneration gas sprayed from the regeneration gas branch pipe reduces PdO formed in the methane oxidation catalyst.
According to paragraph 1,
Inside the reactor, a plurality of methane oxidation catalysts are arranged at intervals along the direction of exhaust gas, and a regeneration gas branch pipe is extended for each methane oxidation catalyst. A methane oxidation catalyst regeneration device.
According to claim 1 or 2,
A methane oxidation catalyst regeneration device characterized in that the regeneration gas branch pipe is equipped with a valve to control the supply of regeneration gas from the regeneration gas supply line to the regeneration gas branch pipe.
According to claim 1 or 2,
A methane oxidation catalyst regeneration device characterized in that the regeneration gas supply line is equipped with a valve to control the supply of regeneration gas to the regeneration gas supply line.
A method of regenerating a methane oxidation catalyst by reducing PdO formed in the methane oxidation catalyst,
Closing the reactor equipped with the methane oxidation catalyst;
A methane oxidation catalyst regeneration method comprising the step of reducing PdO by injecting regeneration gas upstream of the methane oxidation catalyst.
According to clause 5,
A method for regenerating a methane oxidation catalyst, characterized in that it further comprises the step of selectively performing regeneration of the methane oxidation catalyst by supplying regeneration gas to only some of the methane oxidation catalysts among the plurality of methane oxidation catalysts mounted inside the reactor.
According to clause 5,
A method for regenerating a methane oxidation catalyst, characterized in that it further comprises the step of supplying regeneration gas to each of a plurality of methane oxidation catalysts mounted inside the reactor to regenerate the entire methane oxidation catalyst.

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