Search

KR-20260065930-A - Exhaust gas methane emission reduction device and method of operation of the exhaust gas methane emission reduction device

KR20260065930AKR 20260065930 AKR20260065930 AKR 20260065930AKR-20260065930-A

Abstract

The present invention is a device (10) for reducing exhaust methane emissions from internal combustion piston engines, - A housing (12) having the exhaust gas inlet (14) and the exhaust gas outlet (16) that define the normal flow direction of exhaust gas from the exhaust gas inlet (14) to the exhaust gas outlet (16) when in use, - A methane oxidation catalyst (18) disposed within the housing (12) and for reducing the methane concentration in the exhaust gas, and - A sulfur guard bed (20) for removing methane oxidation catalyst toxic substances from the exhaust gas, wherein the sulfur guard bed (20) is arranged upstream of the methane oxidation catalyst (18) in the normal flow direction of the exhaust gas within the housing (12), - A second gas outlet (22) connected to an outlet conduit (23) provided with a first valve (24) between the sulfur guard bed (20) and the methane oxidation catalyst (18), - Guard gas inlet (26) between the methane oxidation catalyst (18) and the exhaust gas outlet (16), and - A second valve (28) is provided between the guard gas inlet (26) and the outlet (16). The present invention also relates to a method for operating the device.

Inventors

  • 또르꿀라 얀
  • 낀나리 뻬까
  • –y또넨 로베르뜨

Assignees

  • 바르실라 핀랜드 오이

Dates

Publication Date
20260511
Application Date
20231002

Claims (15)

  1. As a device (10) for reducing exhaust methane emissions from internal combustion piston engines, - A housing (12) having the exhaust gas inlet (14) and the exhaust gas outlet (16) that define the normal flow direction of exhaust gas from the exhaust gas inlet (14) to the exhaust gas outlet (16) when in use, - A methane oxidation catalyst (18) disposed within the housing (12) and for reducing the methane concentration in the exhaust gas, and - A sulfur guard bed (20) for removing methane oxidation catalyst toxic substances from the exhaust gas, wherein the sulfur guard bed (20) comprises the sulfur guard bed (20) arranged upstream of the methane oxidation catalyst (18) in the normal flow direction of the exhaust gas within the housing (12). The above device includes, - A second gas outlet (22) connected to an outlet conduit (23) provided with a first valve (24) between the sulfur guard bed (20) and the methane oxidation catalyst (18), - Guard gas inlet (26) between the methane oxidation catalyst (18) and the exhaust gas outlet (16), and - A methane exhaust emission reduction device (10) characterized by having a second valve (28) arranged between the guard gas inlet (26) and the outlet (16).
  2. In paragraph 1, A methane emission reduction device (10) characterized in that the methane oxidation catalyst and the sulfur guard bed (20) are spaced apart from each other to form a space (21) between them, and the second gas outlet (22) is opened into the space (21).
  3. In paragraph 1 or 2, The exhaust gas methane emission reduction device (10) is characterized in that the second gas outlet (22) is fluidly connected to a first bypass conduit (30) extending between the upstream side of the methane oxidation catalyst and the upstream side of the exhaust gas outlet in the housing.
  4. In paragraph 1, The above sulfur guard bed (20) is characterized by including a sulfur removal bed made of solid material, and the exhaust gas methane emission reduction device (10).
  5. In paragraph 4, The above sulfur guard bed (20) is characterized by including a lateral flow reactor, and the exhaust gas methane emission reduction device (10).
  6. In paragraph 1, Exhaust gas methane emission reduction device (10), characterized in that the guard gas inlet (26) is controllably connected to a pressurized air supply source (32).
  7. In any one of paragraphs 1 through 6, Exhaust gas methane emission reduction device (10), characterized in that the above device (10) includes a second bypass conduit (34) extending between the exhaust gas inlet (14) and one of the exhaust gas outlet (16) and the first bypass conduit (30).
  8. A method of operating a device (10) according to any one of claims 1 to 7 connected to an internal combustion piston engine (100), In the above method, the engine (100) is operated by burning methane-containing fuel, the exhaust gas is guided to the device (10) through the exhaust gas inlet (14), the temperature of the sulfur guard bed (20) is monitored, and a target normal operating temperature for the temperature of the sulfur guard bed (20) is set. If the monitored actual temperature of the above sulfur guard bed is below the set target normal operating temperature, The first valve (24) is opened, The second valve (28) is closed, While the exhaust gas passes through the sulfur guard bed (20), the methane oxidation catalyst (18) is bypassed by guiding the exhaust gas to the outlet conduit (23) through the second gas outlet (22), and If the monitored actual temperature of the above sulfur guard bed is equal to or higher than the above target normal operating temperature, The first valve (24) is closed, The second valve (28) is opened, A method of operating the device (10), wherein the exhaust gas passes through the sulfur guard bed (20) and the methane oxidation catalyst (18).
  9. In paragraph 8, Additionally, a method of operation of the device (10), wherein if the monitored actual temperature of the sulfur guard bed is lower than the set target normal operating temperature, the guard gas is introduced into the device through the guard gas inlet (26).
  10. In Paragraph 9, The above guard gas is air, a method of operation of the device (10).
  11. In paragraphs 9 and 10, A method of operation of a device (10) in which the flow rate of air induced through the guard gas inlet (26) is controlled such that the methane oxidation catalyst (18) is protected from exposure to methane oxidation catalyst toxic substances, particularly sulfur in the exhaust gas, so that the air flows through the methane oxidation catalyst (18) in the opposite direction to the normal flow of the exhaust gas within the housing (12).
  12. In Paragraph 11, A method of operating a device (10), wherein the air flow rate and/or temperature is controlled as a feedback signal using one or more of the following variables: exhaust gas pressure at the inlet of the device, exhaust gas velocity at the inlet of the device, exhaust gas mass flow, engine load, and a modeled supply set value provided by engine control, such as a modeled supply set value derived from cylinder pressure and/or supercharged air pressure.
  13. In any one of paragraphs 8 through 12, Additionally, a method of operating the device (10) such that when the monitored actual temperature of the sulfur guard bed (20) is lower than the set target normal operating temperature, the operation of the engine (100) is controlled to increase the temperature of the exhaust gas.
  14. In any one of paragraphs 8 through 12, Additionally, a method of operating the device (10) to heat the exhaust gas of the engine (100) by transferring heat from an auxiliary heater (40, 40') to the exhaust gas when the monitored actual temperature of the sulfur guard bed (20) is lower than the set target normal operating temperature.
  15. In Paragraph 9, The above guard gas is the exhaust gas of the engine (100) from which methane oxidation catalyst toxic substances have been removed, a method of operation of the device (10).

Description

Exhaust gas methane emission reduction device and method of operation of the exhaust gas methane emission reduction device The present invention relates to an apparatus for reducing exhaust gas methane emissions in accordance with the preamble of claim 1. The present invention relates to a method of operating a device for reducing exhaust gas methane emissions in accordance with the preamble of the second independent claim. Natural gas is an abundant and economical substitute for petroleum-derived fuels such as gasoline, kerosene, and diesel. Natural gas contains approximately 70% to approximately 95% methane (CFL). Natural gas in the form of compressed natural gas (CNG) and/or liquefied natural gas (LNG) is increasingly being used as a fuel to replace or in parallel with petroleum-derived fuels (e.g., gasoline, coal, etc.) in engines used in stationary (power generation, rock drilling, etc.) and transmission (offshore, rail, and other road travel) applications. For example, internal combustion engines can burn natural gas (e.g., CNG and LNG) to produce combustion gases containing energy extracted by engine components (e.g., pistons, turbines, etc.) to provide power to the system. Combustion gases may contain unburned methane, oxygen ( O₂ ), carbon dioxide ( CO₂ ), carbon monoxide (CO), nitrogen oxides ( NOx ), water ( H₂O ), nitrogen ( N₂ ), and other gases emitted as exhaust gases from the system. Combustion gases from natural gas engines also contain low levels of sulfur dioxide ( SO₂ ). The SO₂ in the combustion gases is attributed to small levels of sulfur (S) (about 0.1 to about 8 ppm (parts per million)) present in natural gas, diesel pilot (e.g., dual-fuel engines), and lubricating oil. For example, in the case of spark-ignition natural gas engines, the level of SO₂ in the combustion gases depends on the levels of S in the natural gas fuel and the levels of S in the oil, as well as the fuel and oil consumption rates. However, under certain operating conditions, natural gas-fueled engines may not completely burn CH₄ . Consequently, unburned CH₄ may slip into the exhaust gas and be released from the system. For example, natural gas engines operating under lean fuel conditions (e.g., oxygen-rich fuel) can produce exhaust gas containing CH₄ at levels ranging from about 200 ppmv (per million volume) to about 3,000 ppmv. It has been recognized that CH₄ is a more potent greenhouse gas than CO₂ (e.g., 1 mol of CH₄ > 25 mol of CO₂ equivalent). Therefore, it is desirable to develop and deploy exhaust emission reduction systems that eliminate or reduce the amount of CH₄ slip so that the level of CH₄ in the exhaust gas is at or below regulated emission levels. One technique for reducing CH4 includes the oxidation of methane in the presence of a methane oxidation catalyst. WO 2021262219 A1 discloses a method and apparatus for reducing methane emissions from natural gas-fueled engines. The disclosure discloses a dual-bed methane emission reduction system comprising a guard bed for converting, capturing, or otherwise removing methane oxidation catalyst toxic substances from exhaust gases generated from natural gas-fueled engines, and a methane oxidation catalyst bed for converting and reducing methane emissions in the exhaust gases. The proposed solution has the problem that, under certain operating conditions, the guard bed may not be at a temperature sufficient to remove methane oxidation catalyst toxic substances from the exhaust gases. The present invention will be described below with reference to the attached exemplary schematic drawings. FIG. 1 schematically illustrates an apparatus for reducing exhaust gas methane emissions according to one embodiment of the present invention. FIG. 2 schematically illustrates an apparatus for reducing exhaust gas methane emissions according to another embodiment of the present invention. FIG. 3 schematically illustrates an apparatus for reducing exhaust gas methane emissions according to another embodiment of the present invention. FIG. 4 schematically illustrates the device shown in FIG. 2 in relation to a piston internal combustion engine. FIG. 1 schematically illustrates a device (10) for reducing exhaust gas methane emissions. The practical application of the device is to reduce so-called methane slip (unburned methane) that can be generated by a piston internal combustion engine operating using a methane-containing gas, such as natural gas, as fuel. The device (10) includes a housing (12), said housing (12) is provided with an exhaust gas inlet (14) and an exhaust gas outlet (16) to define the normal flow direction of the exhaust gas from the inlet (14) to the outlet (16) within the housing (12) during use. The device (10) includes a methane oxidation catalyst, hereinafter MOC (18), disposed in the housing (12) to reduce the methane concentration in the exhaust gas. The methane oxidation catalyst preferably includes a so-called honeycomb support structure having a sui