Corrosion protection system for fuel supply pipes in ammonia-fueled propulsion engines

Abstract

This invention relates to a system and method for preventing corrosion of the fuel supply pipe in an ammonia-fueled or co-fired engine. More specifically, it relates to a system and method for adsorbing residual ammonia in the fuel supply pipe connecting the engine and the fuel tank using an adsorbent when the ammonia-fueled engine is stopped, and then using the heat of the exhaust gas to desorb the adsorbed ammonia when the engine is started, and providing it as a reducing agent for a catalytic reduction (SCR) device installed at the rear end of the engine.

Description

Technical Field

[0001] This invention relates to a system for preventing corrosion of the fuel supply pipe of an ammonia-fueled or co-fired engine. More specifically, it relates to a system that, when an ammonia-fueled engine is stopped, uses an adsorbent to adsorb the ammonia remaining in the fuel supply pipe connecting the engine and the fuel tank, and then, when the engine is started, uses the heat of the exhaust gas to desorb the adsorbed ammonia and supply it as a reducing agent to a catalytic reduction (SCR) device installed at the rear of the engine. Background Technology

[0002] With stricter carbon emission regulations and reduced use of fossil fuels, there is growing interest in alternative fuels such as ammonia. Consequently, ammonia-fueled engines are being developed for vehicles and ships that previously used diesel or gasoline. However, ammonia is corrosive and can cause serious damage to mucous membranes and upper respiratory tract tissues when inhaled. It also causes pain and redness upon skin contact and blurred vision, pain, and eye damage upon contact with the eyes. Therefore, if ammonia remains in the fuel lines flowing into the engine, it can corrode the lines, potentially leading to ammonia leaks. Measures to prevent this are necessary. Furthermore, if only inert gases like nitrogen are used to remove ammonia from the lines to prevent corrosion, the ammonia will simply leak into the air.

[0003] In Korean Patent Publication No. 10-2014-0089229, a method for controlling the leakage of unburned ammonia (NH3) from an engine is disclosed as a method to ensure that ammonia leakage in the exhaust gas of a dual-fuel (Dual) or bi-fuel (BI-FUEL) engine using ammonia as fuel meets a set standard. However, no method is described for purifying and treating the ammonia remaining in the fuel supply pipe connecting the engine and the fuel tank after the engine starts and stops. Furthermore, Korean Patent No. 10-2111525 discloses a fuel supply system for an environmentally friendly ship that selectively uses existing fuel and ammonia fuel, or a mixture thereof, as fuel for the ship's propulsion and generator engines. While it discloses a system for controlling the supply ratio of existing fuel and ammonia fuel by detecting the concentration of greenhouse gases, including carbon dioxide (CO2), it does not mention a system or method for adsorbing and utilizing the ammonia remaining in the ammonia fuel supply pipe flowing into the engine. Summary of the Invention

[0004] Technical issues

[0005] The purpose of this invention is to solve the problems existing in the prior art. As a solution not mentioned or disclosed in the prior art, it aims to provide a system and method for preventing corrosion of the ammonia fuel supply pipe connected to an engine that burns ammonia fuel alone or in combination with ammonia fuel. It relates to a system and method in which an adsorbent is used to adsorb the ammonia remaining in the fuel supply pipe connecting the engine and the fuel tank when the ammonia fuel-powered engine is stopped, and then the heat of the exhaust gas is used to desorb the adsorbed ammonia when the engine is started, and the ammonia is used as a reducing agent in a catalytic reduction device installed at the rear end of the engine.

[0006] Methods for solving technical problems

[0007] The objective of this invention is achieved through a corrosion-resistant system for a fuel supply pipe of an ammonia-fueled propulsion engine. Specifically, the system includes: an engine; a fuel tank storing a first fuel supplied to the engine as fuel; an ammonia tank storing ammonia supplied to the engine as fuel via an ammonia fuel supply pipe; and a catalytic reduction device disposed on an exhaust gas discharge line from the engine for removing nitrogen oxides contained in the exhaust gas. The system further includes a nitrogen tank and an ammonia adsorption device connected to the ammonia fuel supply pipe, the ammonia adsorption device being connected to the exhaust gas discharge line via an exhaust gas supply pipe and a desorbed ammonia supply pipe. This corrosion-resistant system achieves the objective of this invention.

[0008] Alternatively, the present invention can be implemented through a method for preventing corrosion of the fuel supply pipe in an ammonia-fueled propulsion engine, which includes: a step of removing ammonia remaining in the ammonia fuel supply pipe of the fuel supply pipe corrosion prevention system for an ammonia-fueled propulsion engine, and a step of utilizing the ammonia. Specifically, the ammonia removal step includes: a step of confirming engine stop (S100); a step of purging the ammonia fuel remaining in the ammonia fuel supply pipe to an ammonia adsorption device, and a step of interrupting the purging (S200).

[0009] The steps for utilizing ammonia include: confirming engine start (step S300); bypassing the exhaust gas through the exhaust gas discharge line to the ammonia adsorption device and supplying the desorbed ammonia to the catalytic reduction device (step S400); and interrupting the bypassing of the exhaust gas (step S500).

[0010] Invention Effects

[0011] The system and method provided by this invention can prevent pipeline corrosion caused by ammonia remaining in the pipelines flowing into the engine, thereby preventing ammonia leakage accidents. Attached Figure Description

[0012] Figure 1 This is a simplified schematic diagram illustrating the corrosion protection system for the ammonia fuel supply pipe of the present invention.

[0013] Figure 2a This is a diagram showing the sequence of removing residual ammonia from the fuel supply pipe in the ammonia fuel supply pipe anti-corrosion method of the present invention.

[0014] Figure 2b This is a diagram showing the ammonia utilization sequence in the corrosion prevention method for the ammonia fuel supply pipe of the present invention, which desorbs ammonia adsorbed on the ammonia adsorption device so that it can be used for SCR. Detailed Implementation

[0015] The present invention will now be described in detail with reference to the accompanying drawings. However, the embodiments described in this application and the configuration shown in the drawings are merely one preferred embodiment of the present invention and do not fully represent the technical concept of the present invention. Therefore, it should be understood that at the time of this application, there may be various equivalents and modifications that can replace them.

[0016] definition:

[0017] In this application, an ammonia-fueled propulsion engine refers to an engine that uses ammonia as fuel alone or mixes ammonia with existing fuels, such as gasoline-ammonia or natural gas-ammonia. For co-fuel engines, examples include vehicle or marine engines that use existing fuels and liquid ammonia fuel (Bi fuel) separately, or a mixture of both (Dual). The engine can be an oil engine or a gas engine. For oil engines, liquid ammonia fuel is supplied from the fuel tank to the engine connection at 70 bar via a delivery pump and an ammonia supply pipe. It is then pressurized to 600-700 bar by a turbocharger and fuel injection valve and injected into the cylinders. This application aims to implement an anti-corrosion system for the ammonia fuel supply pipe. This embodiment illustrates a co-fuel engine using fuels separately, and the cycle driven by ammonia fuel is described. In addition, as a waste gas emission reduction device, a catalytic reduction device (SCR) refers to a device that uses a catalyst to control NOx. There are methods for directly decomposing NOx (without using a reducing agent) and catalytic reduction methods that use a reducing agent. However, in this application, it refers to a catalytic reduction device that uses a reducing agent and uses ammonia recovered from an ammonia adsorption device as a reducing agent.

[0018] Ammonia-fueled propulsion engines are considered futuristic engines because the thermal combustion of ammonia, which typically produces nitrogen and water, can be explained by the following reaction and can meet greenhouse gas emission regulations.

[0019] 4NH3 + 3O2 → 2N2 + 6H2O + heat

[0020] However, ammonia is corrosive to copper, copper alloys, nickel alloys with a concentration of 6% or higher, and plastics. Therefore, corrosion problems in fuel systems, particularly in fuel supply lines, are attracting increasing attention.

[0021] Figure 1 This invention relates to a structural diagram of a corrosion protection system for a fuel supply pipe used in an ammonia-fueled propulsion engine.

[0022] Reference Figure 1 It is understood that the corrosion protection system (System, S) for the fuel supply pipe of an ammonia fuel propulsion engine according to the present invention includes: an engine (E); a fuel storage tank 100 storing a first fuel supplied to the engine as fuel; an ammonia storage tank 200 storing ammonia supplied to the engine as alternative fuel via a fuel supply pipe L10; and a catalytic reduction device (SCR) disposed on an exhaust gas discharge line L20 from the exhaust gas of the engine for removing nitrogen oxides (NOx) contained in the exhaust gas. The system further includes: a nitrogen storage tank 300 and an ammonia adsorption device 400 respectively connected to the ammonia fuel supply pipe, the ammonia adsorption device being connected to the exhaust gas discharge line via an exhaust gas supply pipe L21 and a desorbed ammonia supply pipe L26.

[0023] The ammonia fuel supply pipe L10 and the nitrogen storage tank 300 are connected by the nitrogen supply pipe L11, and the ammonia fuel supply pipe L10 and the ammonia adsorption device 400 are connected by the residual ammonia conveying pipe L16.

[0024] Of course, in the listed co-fired engine system (S), a first fuel supply pipe and valve are provided for supplying the first fuel (e.g., gasoline, diesel, natural gas, etc.) to the engine. Additionally, a control valve V11 for regulating the supply of ammonia and nitrogen, and a control valve V16 for regulating the delivery of ammonia remaining in the fuel supply pipe are respectively installed on the ammonia fuel supply pipe L10. A heater (not shown) for adjusting the ammonia to a suitable engine (E) temperature can be installed on the ammonia fuel supply pipe L10. Furthermore, a control valve V21 for regulating the supply of exhaust gas is installed on the exhaust gas supply pipe L21, and a control valve V26 for regulating the supply of ammonia desorbed from the adsorption unit according to the exhaust gas is installed on the desorbed ammonia supply pipe L26. Furthermore, although... Figure 1 Although not shown in the figure, the ammonia adsorption device 400 can be equipped with front-end sensors and back-end sensors that can detect the temperature and ammonia concentration at the front and back ends of the adsorption device, respectively.

[0025] The ammonia adsorption unit 400 contains an ammonia adsorbent (e.g., zeolite). When the engine stops, it adsorbs the ammonia supplied in the fuel supply pipe. The adsorbent can be made into granules, monoliths, etc., depending on the adsorption conditions. Simultaneously, during ammonia desorption, a portion of the high-temperature engine exhaust gas is used to desorb the adsorbed ammonia. Therefore, the adsorption unit does not require an additional heater, and the desorbed ammonia is reused as a reducing agent by the SCR unit, preventing leakage.

[0026] The first fuel stored in fuel tank 100 and the ammonia stored in ammonia tank 200 can be used as fuel for the engine (E). In this case, the first fuel and ammonia can be selectively supplied to the engine (E) or supplied together. That is, in this invention, the engine can be driven by supplying the first fuel from fuel tank 100 alone, or by supplying the ammonia fuel stored in ammonia tank 200 alone, or by supplying the first fuel and ammonia fuel together to drive the engine using a mixed fuel. However, for the sake of simplicity, the corrosion protection system for the fuel supply pipe of the ammonia-fueled propulsion engine according to the invention illustrates the case of operation in an ammonia supply mode where only ammonia fuel is supplied as fuel for the engine (E).

[0027] Figure 2 is a diagram illustrating the corrosion prevention control sequence of the ammonia fuel supply pipe in an engine using ammonia as fuel according to an embodiment of the present invention. Figure 2a This is a diagram illustrating the removal sequence of residual ammonia in the fuel supply pipe in the ammonia fuel supply pipe anti-corrosion method of the present invention. Figure 2b This is a diagram showing the ammonia utilization sequence in the ammonia fuel supply pipe corrosion prevention method of the present invention, which desorbs ammonia adsorbed on the ammonia adsorption device and supplies it to the SCR for use.

[0028] like Figure 2a As shown, the steps for removing ammonia remaining in the ammonia fuel supply pipe include: step S100, confirming that the engine has stopped; and step S200, purging the remaining ammonia fuel in the ammonia fuel supply pipe L10 to the ammonia adsorption device 400 and interrupting the purging.

[0029] First, in S100, it is confirmed that the engine is stopped. If the ammonia-fueled engine stops, a considerable amount of ammonia will remain in the fuel supply pipe L10 connecting the engine (E) and the ammonia storage tank 200, which can cause corrosion. Therefore, if the engine stops, the ammonia remaining in the fuel supply pipe L10 is purged by adjusting control valves V11 and V16 using an inert gas (e.g., nitrogen), and then transported to the ammonia adsorption unit 400 through the residual ammonia delivery pipe L16. Specifically, in S201, valve V11 is adjusted to block the inflow of ammonia fuel from the ammonia storage tank 200, and valve V16 is adjusted to allow nitrogen filled in the nitrogen storage tank 300 to flow through the nitrogen supply pipe L11 and the residual ammonia delivery pipe L16, thereby forcibly transporting the residual ammonia to the ammonia adsorption unit 400. Preferably, valves V11 and V16 can be opened and closed simultaneously, but this is not a limitation; either V11 or V16 can be opened and closed first, followed by the other valve. Then, if the ammonia concentration detected by the front-end sensor (not shown) of the ammonia adsorption device 400 is below 10 ppm, it is determined that the ammonia remaining in the fuel supply pipe L10 has been completely transported and adsorbed by the adsorbent (e.g., zeolite) in the ammonia adsorption device. Next, in S202, valve V11 is adjusted to block the inflow of nitrogen from the nitrogen storage tank 300, and valve V16 is adjusted to block the path of the fuel supply pipe L10 and the residual ammonia transport pipe L16, thereby completing the step of removing residual ammonia.

[0030] Inside the ammonia adsorption unit 400, ammonia is adsorbed by an adsorbent. When the engine starts, the heat of the exhaust gas is used to desorb the adsorbed ammonia, which is then supplied to the catalytic reduction unit (SCR) installed at the rear of the engine as a reducing agent.

[0031] like Figure 2b As shown, the steps for utilizing ammonia include: step S300, confirming engine start; step S400, diverting (bypassing) the exhaust gas through the exhaust gas discharge line to the ammonia adsorption device and providing the desorbed ammonia to the catalytic reduction device; step S500, interrupting the diversion of exhaust gas.

[0032] First, in S300, it is confirmed whether the engine is running. The heat of the engine exhaust gas can be used to desorb the adsorbed ammonia. Therefore, if the engine is running, control valves V21 and V26 are adjusted to use the high-temperature exhaust gas to desorb the ammonia adsorbed inside the ammonia adsorption device 400 and use it as a reducing agent for the SCR. Specifically, valve V21 is opened to allow a portion of the exhaust gas to flow into the ammonia adsorption device 400. At the same time, valve V26 is opened to supply the desorbed ammonia to the exhaust gas discharge line L20, thereby providing the desorbed ammonia to the SCR. Preferably, valves V21 and V26 can be opened and closed simultaneously, but this is not a limitation. Alternatively, V21 or V26 can be opened or closed first, followed by the other valve. Then, if the ammonia concentration detected by the rear sensor (not shown) of the ammonia adsorption device 400 is below 10 ppm, it is determined that all the ammonia adsorbed in the adsorption device 400 has been desorbed and is supplied to the SCR through the desorbed ammonia supply pipe L26. Next, adjust valve V21 to block the diversion of exhaust gas and shut off valve V26 to interrupt the supply of desorbed ammonia to the SCR, thereby completing the utilization step of desorbed ammonia.

[0033] The above description of the present invention is merely an exemplary introduction. It should be understood that those skilled in the art to which this invention pertains can easily implement modifications in other specific forms without altering the technical concept or essential features of the invention. Therefore, the embodiments described above are intended to exemplify the present invention from various aspects and do not limit the scope of the invention. Thus, the scope of the invention is embodied in the following claims, and the meaning and scope of the claims, as well as all modifications or variations derived from their equivalents, are included within the scope of the invention.

Claims

1. A corrosion protection system for the fuel supply pipe of an ammonia fuel-propelled engine, characterized in that, include: engine; A fuel storage tank that stores the first fuel supplied to the engine as fuel; An ammonia storage tank that stores ammonia as fuel and supplies it to the engine via an ammonia fuel supply pipe; as well as A catalytic reduction device, installed in the exhaust gas discharge line from the engine, is used to remove nitrogen oxides contained in the exhaust gas. The corrosion protection system also includes a nitrogen storage tank and an ammonia adsorption device, which are respectively connected to the ammonia fuel supply pipe. The ammonia adsorption device is connected to the waste gas discharge line through a waste gas supply pipe and a desorption ammonia supply pipe.

2. A corrosion protection system, specifically a corrosion protection system for the fuel supply pipe of an ammonia fuel-propelled engine, characterized in that, include: engine; An ammonia storage tank that stores ammonia as fuel and supplies it to the engine via an ammonia fuel supply pipe; as well as A catalytic reduction device, installed in the exhaust gas discharge line from the engine, is used to remove nitrogen oxides contained in the exhaust gas. The corrosion protection system also includes a nitrogen storage tank and an ammonia adsorption device, which are respectively connected to the ammonia fuel supply pipe. The ammonia adsorption device is connected to the waste gas discharge line through a waste gas supply pipe and a desorption ammonia supply pipe.

3. The anti-corrosion system according to claim 1 or 2, characterized in that, The ammonia adsorption device contains a granular or monolithic column-shaped adsorbent.

4. The anti-corrosion system according to claim 3, characterized in that, The adsorbent is zeolite.

5. A corrosion prevention method, specifically a corrosion prevention method for the fuel supply pipe of an ammonia fuel propulsion engine, characterized in that, include: The steps of removing ammonia remaining in the ammonia fuel supply pipe of the corrosion protection system according to claim 1 and the steps of utilizing the removed ammonia.

6. The corrosion prevention method according to claim 5, characterized in that, The ammonia removal step includes: Confirm engine stop procedure (S100); The process of purging the ammonia fuel remaining in the ammonia fuel supply pipe to the ammonia adsorption unit includes a purging step and a purging interruption step (S200).

7. The corrosion prevention method according to claim 5, characterized in that, The ammonia utilization steps include: Confirm engine start procedure (S300); The steps of diverting the waste gas through the waste gas discharge line to the ammonia adsorption unit and supplying the desorbed ammonia to the catalytic reduction unit (S400); Step S500: Interrupt the diversion of exhaust gas.

8. The corrosion prevention method according to claim 6, characterized in that, The purging step utilizes nitrogen flowing in from the nitrogen storage tank for purging.

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