KR20230044863A - Methane oxidation catalyst regeneration device and regeneration method - Google Patents

Abstract

The present invention relates to an apparatus and method for regenerating a methane oxidation catalyst that oxidizes methane, and in particular, the inside of a reactor equipped with a methane oxidation catalyst is formed in a rich burn state to reduce PdO formed in the methane oxidation catalyst. It relates to a device and method for regenerating a methane oxidation catalyst.
The methane oxidation catalyst regeneration apparatus according to the present invention for achieving the above object includes a reactor equipped with a methane oxidation catalyst and a rich burn operating burner for burning oxygen contained in exhaust gas inside the reactor, and the methane oxidation catalyst A method of regenerating the methane oxidation catalyst by reducing the PdO formed in the step of closing the reactor equipped with the methane oxidation catalyst, exhausting the exhaust gas inside the closed reactor to the outside of the reactor, and then re-injecting and circulating; It is technically characterized by including a combustion step of burning the oxygen of the circulating exhaust gas to create a rich burn state inside the reactor.

Description

Methane oxidation catalyst regeneration device and regeneration method

The present invention relates to an apparatus and method for regenerating a methane oxidation catalyst that oxidizes methane, and in particular, the inside of a reactor equipped with a methane oxidation catalyst is formed in a rich burn state to reduce PdO formed in the methane oxidation catalyst. It relates to a device and method for regenerating a methane oxidation catalyst.

Natural gas fuel is attracting attention as an eco-friendly fuel because it emits very little air pollutants such as sulfur oxides, nitrogen oxides, and particulate matter (PM) compared to conventional fuels. Because of these advantages, the use of engines using natural gas as fuel is increasing in ships and automobiles.

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

On the other hand, methane (CH4) is a strong greenhouse gas as a global warming gas substance that is 28 times more than equivalent amount of carbon dioxide (CO2). In order to solve the problem of global warming, the amount of methane emitted from exhaust gas must be reduced. Recently, according to the International Maritime Organization's strengthened regulation for reducing GHG (Green House gases) emissions, GHG emissions such as carbon dioxide (CO2) Regulations are being discussed, and technology that does not emit methane into the atmosphere is required.

In accordance with such a demand, in order to efficiently purify exhaust gases such as internal combustion engines, which act as a major cause of environmental pollution, in particular, various studies on methods for efficiently removing methane contained in exhaust gases in large quantities are in progress.

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

Recently, catalysts in which noble metals are supported on oxide carriers such as alumina, and palladium or platinum supported on alumina are widely known, and fuel lean atmospheres ( 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) is generated, and methane oxidation performance is reduced by PdO.

Therefore, in order to remove methane using a palladium-based methane oxidation catalyst, it is urgent to develop catalyst regeneration technology to remove PdO generated in the methane oxidation catalyst, especially when the engine is operated in a lean-burn condition. However, there is a problem in that excessive oxygen reacts with the methane oxidation catalyst and significantly increases 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 when the methane oxidation catalyst is reduced in methane oxidation performance by PdO, the inside of the reactor is formed in a rich burn state, so that the methane oxidation catalyst The purpose is to provide a methane oxidation catalyst regeneration device and regeneration method for regenerating.

In order to achieve the above object, the methane oxidation catalyst regeneration apparatus according to the present invention includes a reactor equipped with a methane oxidation catalyst and a rich burn operating burner for burning oxygen contained in exhaust gas inside the reactor. do.

In addition, according to a preferred embodiment of the present invention, a circulation passage connecting both ends of the reactor to circulate the exhaust gas inside the reactor is further included, and the rich burn operation burner is mounted on the circulation passage and the exhaust gas flows along the circulation passage. of oxygen is burned to reduce PdO formed in the methane oxidation catalyst.

In addition, according to a preferred embodiment of the present invention, the reactor has an inlet formed at the bottom of the reactor so that exhaust gas discharged from the engine flows into the reactor, an outlet through which exhaust gas is discharged is formed at the top of the reactor, and an inlet is formed at the inlet. A valve is mounted, and the outlet is equipped with an outlet valve.

In addition, according to a preferred embodiment of the present invention, a plurality of methane oxidation catalysts are mounted at intervals in the vertical direction inside the reactor, and both ends of the circulation passage are the upper part of the reactor above the area where the methane oxidation catalysts are installed and the methane oxidation It is connected to the bottom of the reactor below the section where the catalysts are mounted.

In addition, according to a preferred embodiment of the present invention, a branch passage is extended to the circulation passage extending from the top of the reactor to the rich burn operation burner.

In addition, according to a preferred embodiment of the present invention, an on-off valve is installed in the branch flow path, and the on-off valve is closed during methane oxidation reaction and opened when the methane oxidation catalyst is regenerated.

Further, according to a preferred embodiment of the present invention, the branch flow path branched from the circulation flow path joins the exhaust pipe connected to the economizer from the turbo charger.

The present invention is a method for regenerating a methane oxidation catalyst by reducing PdO formed in the methane oxidation catalyst, comprising the steps of closing a reactor equipped with the methane oxidation catalyst, exhausting the exhaust gas inside the closed reactor to the outside of the reactor and reinjecting the and a combustion step of burning the oxygen of the circulating exhaust gas to form the inside of the reactor in a rich burn state.

In addition, according to a preferred embodiment of the present invention, the exhaust gas is exhausted from the top of the methane oxidation catalyst installed inside the reactor, and the exhaust gas is re-injected and circulated to the bottom of the methane oxidation catalyst.

As described above, the methane oxidation catalyst regeneration apparatus and regeneration method according to the present invention re-burn the exhaust gas with a regeneration burner and then inject it into the reactor, thereby forming the inside of the reactor in a rich burn state, thereby regenerating the methane oxidation catalyst By reducing the PdO formed in the methane oxidation performance is improved. The methane oxidation catalyst regenerated through the reduction of PdO has improved methane oxidation performance and can minimize methane discharged into the atmosphere.

1 is a conceptual diagram showing a methane oxidation catalyst regeneration apparatus according to the present invention;
FIG. 2 is a conceptual diagram illustrating an example in which the inside of a reactor is formed in a rich burn state by operating the regenerative burner shown in FIG. 1 .

Hereinafter, a preferred embodiment of a methane oxidation catalyst regeneration apparatus and regeneration method according to the present invention will be described in detail with reference to the accompanying drawings.

In the drawings, FIG. 1 is a conceptual diagram showing a methane oxidation catalyst regeneration apparatus according to the present invention, and FIG. 2 is a conceptual diagram showing an example in which the inside of a reactor is formed in a rich burn state by operating the regeneration burner shown in FIG.

As shown in FIG. 1, 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 extends into the atmosphere.

Accordingly, the exhaust gas generated from the engine 10 is introduced into the reactor 110 along the front end exhaust pipe 11F.

In the reactor 110, an inlet 111 to which the front end exhaust pipe 11F is connected is formed at the bottom thereof, and an outlet 113 to which the rear end exhaust pipe 11B is connected is formed at the top of the reactor 110, and the inlet 111 ) is equipped with an inlet valve (111V) and an outlet valve (113V) is attached to 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 in ) is introduced into the reactor 110 along the front end exhaust pipe 11F and then exhausted to the outside of the reactor 110 along the rear end exhaust pipe 11B.

Meanwhile, a methane oxidation catalyst (MOC) 120 is installed inside the reactor 110 . As an example, as the 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 introduced into the inlet 111 flows toward the outlet 113 while the plurality It passes through the methane oxidation catalyst 120 in sequence.

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

Therefore, methane introduced into the reactor 110 is oxidized to water and carbon dioxide as shown in Chemical Formula 1 while passing through the methane oxidation catalyst 120 and then exhausted through the downstream exhaust pipe 11B.

Methane is a global warming gas substance that is 28 times stronger than carbon dioxide, and as methane is oxidized to emit carbon dioxide, global warming can be reduced compared to methane emissions.

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

An object of the present invention is to regenerate the methane oxidation catalyst 120 so as to improve the oxidation performance of methane generated when PdO, an oxidizing agent, is formed in the methane oxidation catalyst 120. To this end, a circulation passage 130 connecting the front end of the reactor 110 and the rear end of the reactor 110 is formed, and a rich burn operation burner 140 is installed in the circulation passage 130 .

Further, a branch passage 131 is extended to the circulation passage 130 located between the rear end of the reactor 110 and the rich burn operating burner 140, and the branch passage 131 is an economizer (Economizer) in the turbo charger (T/C). ) connected to the extended exhaust pipe.

In the methane oxidation catalyst regeneration apparatus configured as described above, methane contained in the exhaust gas is oxidized while the exhaust gas passes through the methane oxidation catalyst 120 inside the reactor 110 at normal times, thereby minimizing the emission of methane.

In this state, as described above, when PdO, an oxidizing substance, is formed in the methane oxidation catalyst 120, the oxidation performance is reduced. The methane oxidation catalyst 120 is regenerated by reducing PdO formed in the methane oxidation catalyst 120.

To this end, the inlet valve 111V and the outlet valve 113V mounted on the inlet 111 and the outlet 113 of the reactor 110 are closed. In addition, when the rich burn operating burner 140 is operated, the exhaust gas filled in the reactor 110 circulates along the circulation passage 130 and the oxygen contained in the exhaust gas is burned, resulting in a rich burn condition in which the oxygen concentration is reduced. .

Oxygen formed in the methane oxidation catalyst 120 while reducing the oxygen concentration in the reactor 110 is reduced to PdO while the methane oxidation catalyst 120 is regenerated.

In addition, combustion gas according to the operation of the rich burn operating burner 140 circulates through the reactor 110 and the circulation passage 130 as shown in FIG. 2 , while a portion of the combustion gas is exhausted through the branch passage 131 .

When the methane oxidation catalyst 120 is regenerated, the rich burn operation burner 140 is stopped, the on-off valve 131V formed in the branched passage 131 is closed, and the inlet valve 111V and the outlet valve of the reactor 110 ( 113V) is opened, and the exhaust gas generated from the engine 10 is introduced toward the reactor 110 to oxidize and remove methane contained in the exhaust gas.

10 : engine
11F, 11B: exhaust pipe
110: reactor
111: inlet
111V: inlet valve
113: outlet
113V: Outlet valve
120: methane oxidation catalyst (MOC)
130: circulation flow path
131: branch passage (131)
131V: open/close valve
140: rich burn driving burner

Claims (9)

A reactor equipped with a methane oxidation catalyst;
A methane oxidation catalyst regeneration apparatus comprising a rich burn operation burner for burning oxygen contained in exhaust gas inside the reactor.
According to claim 1,
Further comprising a circulation passage connecting both ends of the reactor to circulate the exhaust gas inside the reactor,
The rich burn operating burner is mounted on the circulation passage and burns oxygen in the exhaust gas flowing along the circulation passage to reduce PdO formed in the methane oxidation catalyst.
According to claim 1 or 2,
In the reactor, an inlet is formed at the bottom of the reactor so that exhaust gas discharged from the engine flows into the reactor, an outlet for exhaust gas is discharged at the top of the reactor, an inlet valve is installed at the inlet port, and an outlet valve is installed at the outlet port. Methane oxidation catalyst regeneration apparatus, characterized in that.
According to claim 3,
Inside the reactor, a plurality of methane oxidation catalysts are mounted at intervals in the vertical direction, and both ends of the circulation flow path are connected to the upper part of the reactor, which is above the area where the methane oxidation catalysts are installed, and the lower part of the reactor, below the area where the methane oxidation catalysts are installed. Methane oxidation catalyst regeneration apparatus, characterized in that.
According to claim 4,
Methane oxidation catalyst regeneration apparatus, characterized in that the branch flow path is extended in the circulation flow path extending from the upper part of the reactor to the rich burn operating burner.
According to claim 5,
An on-off valve is installed in the branch flow path, and the on-off valve is closed during the methane oxidation reaction and the open-off valve is opened when the methane oxidation catalyst is regenerated.
According to claim 5,
The branch flow path branched from the circulation flow path is a methane oxidation catalyst regeneration device, characterized in that joined to the exhaust pipe connected to the economizer from the turbo charger.
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;
Exhausting the exhaust gas inside the closed reactor to the outside of the reactor and then re-injecting and circulating;
A method for regenerating a methane oxidation catalyst comprising a combustion step of burning oxygen in circulating exhaust gas to create a rich burn state inside the reactor.
According to claim 8,
A method for regenerating a methane oxidation catalyst, characterized in that exhaust gas is exhausted from the top of the methane oxidation catalyst mounted inside the reactor and the exhaust gas is re-injected and circulated to the bottom of the methane oxidation catalyst.

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