Engine systems and ships containing them

Abstract

The present invention relates to an engine system comprising: an engine that uses ammonia fuel; a gas receiver located downstream of the engine and containing exhaust gas generated by the engine; and a connecting section that connects the engine and the gas receiver, through which exhaust gas generated by the engine is discharged from the gas receiver. The connecting section is provided with a catalyst layer in the portion through which the exhaust gas passes. The catalyst layer is either a selective catalytic reduction layer in which ammonia in the exhaust gas acts as a reducing agent to carry out a selective catalytic reduction (SCR) reaction and remove nitrogen oxides, or, under conditions in which ammonia and nitrogen oxides are present in the exhaust gas, ammonia in the exhaust gas acts as a reducing agent to carry out a selective catalytic reduction (SCR) reaction and remove nitrogen oxides, and under conditions in which nitrogen oxides are not present in the exhaust gas, ammonia in the exhaust gas is oxidized and removed.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0098116 filed on July 27, 2023, Korean Patent Application No. 10-2023-0142169 filed on October 23, 2023, and Korean Patent Application No. 10-2024-0052169 filed on April 18, 2024, and all the contents disclosed in the documents of the corresponding Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to an exhaust gas aftertreatment system and an engine system in which a selective catalytic reduction reaction is performed. It also relates to a ship including such an exhaust gas aftertreatment system and an engine system.

Background Art

[0003] After fuel burns in an engine, exhaust gas is generated. The exhaust gas contains harmful substances such as nitrogen oxides, methane, and sulfates, and regulations on these are gradually being strengthened. Therefore, research has been conducted on an exhaust gas aftertreatment system for removing harmful substances contained in the exhaust gas so as to meet the emission amounts required by such regulations.

[0004] As an example of an aftertreatment system, a selective catalytic reduction device (SCR) reduces nitrogen oxides contained in exhaust gas to nitrogen and water by reacting them with a reducing agent and a denitrification catalyst. As another example, ammonia can be oxidized and removed using an ammonia oxidation catalyst (AOC).

[0005] When ammonia is used as fuel, unburned ammonia, or ammonia slip, is released from the engine without being burned. Therefore, the exhaust gas from an engine using ammonia fuel contains both nitrogen oxides and ammonia. Based on these characteristics of ammonia fuel, improvements can be made to the engine system and exhaust gas aftertreatment system. [Overview of the project] [Problems that the invention aims to solve]

[0006] The present invention aims to efficiently remove nitrogen oxides and ammonia contained in exhaust gas generated by an engine that uses ammonia as fuel.

[0007] Furthermore, the present invention aims to temporarily remove nitrogen oxides and ammonia contained in the exhaust gas generated by an engine using ammonia as fuel, within the engine system.

[0008] Furthermore, the present invention aims to efficiently supply the reducing agent necessary for a selective catalytic reduction device that processes exhaust gas generated by an engine using ammonia as fuel.

[0009] Furthermore, the present invention aims to provide a vessel that includes an engine system and an exhaust gas aftertreatment system. [Means for solving the problem]

[0010] An engine system according to one embodiment of the present invention includes an engine that uses ammonia fuel, a gas receiver located downstream of the engine and containing exhaust gas generated by the engine, and a connecting section that connects the engine and the gas receiver, through which exhaust gas generated by the engine is discharged to the gas receiver, wherein the connecting section is provided with a catalyst layer in the portion through which the exhaust gas passes, and the catalyst layer is a selective catalytic reduction layer through which ammonia in the exhaust gas acts as a reducing agent to carry out a selective catalytic reduction (SCR) reaction and remove nitrogen oxides, or under conditions where ammonia and nitrogen oxides are present in the exhaust gas, ammonia in the exhaust gas acts as a reducing agent to carry out a selective catalytic reduction (SCR) reaction and remove nitrogen oxides, and under conditions where nitrogen oxides are not present in the exhaust gas, ammonia in the exhaust gas is oxidized and removed.

[0011] In one example, the system may further include a nitrogen oxide concentration sensor for measuring the concentration of nitrogen oxides in the exhaust gas contained in the gas receiver, and a control unit that controls the supply of a reducing agent for a selective catalytic reduction reaction to the catalyst layer when the nitrogen oxide concentration measured by the nitrogen oxide concentration sensor exceeds a predetermined reference value.

[0012] In one example, the control unit may be controlled to supply additional ammonia to the engine via the engine's fuel supply unit during the exhaust process, in which fuel combustion does not occur during the engine's operation, if the nitrogen oxide concentration measured by the nitrogen oxide concentration sensor exceeds a predetermined reference value.

[0013] In one example, the system further includes a reducing agent supply unit that supplies a reducing agent for a selective catalytic reduction reaction to the catalyst layer, and the control unit can control the supply of a reducing agent for a selective catalytic reduction reaction to the catalyst layer via the reducing agent supply unit when the concentration of nitrogen oxides measured by the nitrogen oxide concentration sensor exceeds a predetermined reference value.

[0014] An engine system according to one embodiment of the present invention may include an engine that uses ammonia fuel and a control unit that controls the engine to supply additional ammonia via the engine's fuel supply unit during the exhaust process in which no fuel is burned during the engine's operation.

[0015] A vessel may include an engine system according to one embodiment of the present invention. [Effects of the Invention]

[0016] According to the present invention, nitrogen oxides and ammonia contained in the exhaust gas generated by an engine using ammonia as fuel can be efficiently removed.

[0017] According to the present invention, nitrogen oxides and ammonia contained in the exhaust gas generated by an engine using ammonia as fuel can be temporarily removed within the engine system, thereby reducing the size of the selective catalytic reduction device downstream of the engine system.

[0018] Furthermore, the present invention can efficiently supply the reducing agent necessary for a selective catalytic reduction device that treats exhaust gas generated by an engine using ammonia as fuel. [Brief explanation of the drawing]

[0019] [Figure 1] This figure shows an exhaust gas aftertreatment system according to a first embodiment of the present invention. [Figure 2] This figure shows an engine system according to a second embodiment of the present invention. [Figure 3] This figure shows an exhaust gas aftertreatment system according to a third embodiment of the present invention. [Figure 4] This figure shows the exhaust gas aftertreatment system according to the fourth embodiment of the present invention. [Modes for carrying out the invention]

[0020] Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. When attaching reference numerals to the components of each drawing, it should be noted that for the same components, even if they are shown on other drawings, they are given the same reference numerals as much as possible. Further, when explaining the embodiments of the present invention, if it is determined that a specific description of a related known configuration or function hinders the understanding of the embodiments of the present invention, the detailed description thereof will be omitted.

[0021] Also, when describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. can be used. Such terms are for distinguishing the components from other components, and the essence, order or sequence of the components are not limited by such terms. When a component is described as being "connected", "coupled" or "joined" to another component, it should be understood that the component may be directly connected or joined to the other component, but there may also be cases where other components are "connected", "coupled" or "joined" between the components.

[0022] In this specification, the front-rear, left-right and up-down directions are defined for the convenience of explanation, and they may be directions orthogonal to each other. However, such directions are relatively determined, and even if they are the up-down directions, they do not necessarily mean the vertical directions.

[0023] <First Embodiment> FIG. 1 is a diagram showing an exhaust gas post-treatment system according to the first embodiment of the present invention.

[0024] Referring to FIG. 1, an exhaust gas aftertreatment system 10 according to a first embodiment of the present invention is an exhaust gas aftertreatment system 10 for treating exhaust gas generated by an engine 20 that uses ammonia as fuel. The system includes a plurality of catalyst layers, and the plurality of catalyst layers include at least one composite ammonia purification layer. In the composite ammonia purification layer, under the condition that ammonia and nitrogen oxides are contained in the exhaust gas, ammonia in the exhaust gas acts as a reducing agent, and a selective catalytic reduction reaction is carried out to remove nitrogen oxides. Under the condition that no nitrogen oxides are contained in the exhaust gas, ammonia in the exhaust gas can be oxidized and removed. Hereinafter, each component will be described in detail.

[0025] The exhaust gas generated by the engine 20 that uses ammonia as fuel contains not only nitrogen oxides but also ammonia that has not been burned in the engine. In order to remove nitrogen oxides and ammonia, the exhaust gas aftertreatment system 10 is provided downstream of the engine.

[0026] The exhaust gas aftertreatment system 10 includes a plurality of catalyst layers, and the plurality of catalyst layers can be composed of multiple stages. Therefore, even if not all of the nitrogen oxides and ammonia in the exhaust gas are removed in the previous catalyst layer, they can be gradually removed through the subsequent catalyst layers. This can improve the removal efficiency of nitrogen oxides and ammonia.

[0027] The plurality of catalyst layers can include at least one composite ammonia purification layer. Existing ammonia purification catalysts only have the function of oxidizing and removing ammonia. However, the composite ammonia purification catalyst can, depending on the conditions, function as an ammonia purification catalyst or as a catalyst for the selective reduction reaction. Specifically, the composite ammonia purification catalyst plays a role such that, under the condition that both ammonia and nitrogen oxides are present in the exhaust gas, ammonia acts as a reducing agent to reduce and remove nitrogen oxides to nitrogen. Instead, under the condition that there is ammonia in the exhaust gas but no nitrogen oxides, it plays a role such that ammonia is oxidized and removed.

[0028] The exhaust gas generated by the engine 20, which uses ammonia as fuel, contains unburned ammonia. In the complex ammonia purification layer, the ammonia in the exhaust gas acts as a reducing agent in a selective catalytic reduction reaction. Therefore, the ammonia contained in the exhaust gas acts as a reducing agent and can be removed by the complex ammonia purification catalyst during the process of removing nitrogen oxides. Once all the nitrogen oxides contained in the exhaust gas have been removed from the preceding complex ammonia purification layer, the subsequent complex ammonia purification layer undergoes a reaction in which the ammonia in the exhaust gas is oxidized and removed. As a result, the exhaust gas discharged from the engine 20 passes through the exhaust gas aftertreatment system 10, which includes the complex ammonia purification layer, and all nitrogen oxides and ammonia are removed.

[0029] Furthermore, multiple catalyst layers can include selective catalytic reduction layers in addition to the combined ammonia purification layer. The combined ammonia purification catalyst used in the combined ammonia purification layer can perform all the roles of both an ammonia purification catalyst and a selective catalytic reduction catalyst, but it is relatively expensive. Therefore, instead of making all catalyst layers combined ammonia purification layers, some can be made into selective catalytic reduction catalyst layers to reduce costs. However, it is preferable to place the combined ammonia purification layer after the selective catalytic reduction layer. This is because if the combined ammonia purification layer is placed before it and all nitrogen oxides are removed from the before stage, no reaction will occur in the subsequent selective catalytic reduction layer. Below, we will explain using an exhaust gas aftertreatment system including three catalyst layers as an example.

[0030] The exhaust gas aftertreatment system 10 according to the first embodiment of the present invention may include a first catalyst layer 11, a second catalyst layer 12, and a third catalyst layer 13. The configuration of each catalyst layer will be described below with examples.

[0031] Each catalyst layer can consist of, for example, a first catalyst layer 11 that removes nitrogen oxides by a selective catalytic reduction reaction, a second catalyst layer 12 located downstream of the first catalyst layer 11 that also removes nitrogen oxides by a selective catalytic reduction reaction, and a third catalyst layer 13 located downstream of the second catalyst layer 12 that is a composite ammonia purification layer.

[0032] In this case, in the first catalytic layer 11 and the second catalytic layer 12, ammonia contained in the exhaust gas acts as a reducing agent to remove nitrogen oxides. In the third catalytic layer 13, any nitrogen oxides that have not been removed in the first catalytic layer 11 and the second catalytic layer 12 are removed, and if all nitrogen oxides have been removed, ammonia can be oxidized and removed.

[0033] Furthermore, as illustrated in Figure 1(b), each catalyst layer can consist of, for example, a first catalyst layer 11 that removes nitrogen oxides by a selective catalytic reduction reaction, a second catalyst layer 12 located downstream of the first catalyst layer 11 and which is a composite ammonia purification layer, and a third catalyst layer 13 located downstream of the second catalyst layer 12 and which is a composite ammonia purification layer.

[0034] In this case, in the first catalytic layer 11, ammonia contained in the exhaust gas acts as a reducing agent to remove nitrogen oxides. In the second catalytic layer 12 and the third catalytic layer 13, any nitrogen oxides that have not been removed from the first catalytic layer 11 are removed, and once all nitrogen oxides have been removed, ammonia can be oxidized and removed.

[0035] Furthermore, as illustrated in Figure 1(c), each catalyst layer can consist of, for example, a first catalyst layer 11 which is a composite ammonia purification layer, a second catalyst layer 12 which is a composite ammonia purification layer located downstream of the first catalyst layer 11, and a third catalyst layer 13 which is a composite ammonia purification layer located downstream of the second catalyst layer 12.

[0036] In this case, nitrogen oxides are first removed in the first catalyst layer 11, the second catalyst layer 12, and the third catalyst layer 13. Once all nitrogen oxides have been removed, ammonia is oxidized and removed.

[0037] The exhaust gas aftertreatment system 10 having the three stages of catalyst layers described above is explained as an example, but this is merely illustrative, and different numbers of stages or different combinations of catalyst layers can be used, taking into consideration the reduction of nitrogen oxides and economic efficiency.

[0038] <Second Embodiment> Figure 2 shows an engine system according to a second embodiment of the present invention.

[0039] Referring to Figure 2, the system includes an engine 20 that uses ammonia fuel, a gas receiver 40 located downstream of the engine 20 and containing the exhaust gas generated by the engine 20, and a connecting section 30 that connects the engine 20 and the gas receiver 40, through which the exhaust gas generated by the engine 20 is discharged from the gas receiver 40. The connecting section 30 is provided with a catalyst layer 35 in the portion through which the exhaust gas passes. The catalyst layer 35 is either a selective catalytic reduction layer in which ammonia in the exhaust gas acts as a reducing agent and a selective catalytic reduction reaction occurs to remove nitrogen oxides, or, under conditions where ammonia and nitrogen oxides are present in the exhaust gas, ammonia in the exhaust gas acts as a reducing agent and a selective catalytic reduction reaction occurs to remove nitrogen oxides, and under conditions where nitrogen oxides are not present in the exhaust gas, ammonia in the exhaust gas is oxidized and removed. The following describes each component in detail.

[0040] The exhaust gas produced by the ammonia-fueled engine 20 may contain nitrogen oxides and unburned ammonia, i.e., ammonia slip. The gas receiver 40 collects the exhaust gas emitted from the engine 20 and supplies it to the turbocharger. This is to stabilize the exhaust gas before supplying it to the turbocharger. In Figure 2, one engine 20 is connected to the gas receiver 40, but multiple engines 20 can also be connected to the gas receiver 40 to collect exhaust gases.

[0041] The connecting section 30, which connects the engine 20 and the gas receiver 40, serves as a passage through which exhaust gas discharged from the engine 20 moves to the gas receiver 40. One end of the connecting section 30 is connected to the engine 20, and the other end of the connecting section 30 is connected to the gas receiver 40.

[0042] A catalyst layer 35 can be provided in the connecting section 30 in the portion through which exhaust gas passes. The catalyst layer 35 can selectively reduce and remove nitrogen oxides contained in the exhaust gas through a catalytic reduction reaction. Alternatively, the catalyst layer 35 may be a composite ammonia purification layer.

[0043] When diesel fuel is used, the exhaust gas does not contain ammonia, and even if a catalyst layer 35 is placed in the connecting section 30, nitrogen oxides are not removed because there is no reducing agent for the selective catalytic reduction reaction. However, when ammonia fuel is used, the exhaust gas contains ammonia, and the ammonia in the catalyst layer 35 acts as a reducing agent for the selective catalytic reduction reaction, allowing nitrogen oxides in the exhaust gas to be removed. Therefore, nitrogen oxides in the exhaust gas are temporarily removed from the catalyst layer 35 in the connecting section 30, and the amount of nitrogen oxides contained in the exhaust gas entering the selective catalytic reduction device that may be placed downstream of the engine system 100 is reduced, thus allowing the size of the downstream selective catalytic reduction device to be reduced.

[0044] The nitrogen oxide concentration sensor 130 can measure the concentration of nitrogen oxides in the exhaust gas contained in the gas receiver 40. The control unit 140 can control the supply of a reducing agent for the selective catalytic reduction reaction to the catalyst layer 35 if the nitrogen oxide concentration measured by the nitrogen oxide concentration sensor 130 exceeds a predetermined reference value.

[0045] If the amount of ammonia slipped from the engine 20, i.e., the amount of reducing agent required for the selective catalytic reduction reaction, is insufficient, and the selective catalytic reduction reaction does not occur sufficiently in the catalyst layer 35, the nitrogen oxide concentration may be measured as high by the nitrogen oxide concentration sensor 130. In such cases, supplying more reducing agent to the catalyst layer 35 can promote the selective catalytic reduction reaction in the catalyst layer 35, thereby lowering the nitrogen oxide concentration measured by the nitrogen oxide concentration sensor 130. The method of supplying the reducing agent for the selective catalytic reduction reaction to the catalyst layer 35 will be described below.

[0046] For example, if the nitrogen oxide concentration measured by the nitrogen oxide concentration sensor 130 exceeds a predetermined standard value, the control unit 140 can control the engine 20 to supply additional ammonia via the engine 20's fuel supply unit 110 to the exhaust process, where fuel combustion does not occur during the engine 20's operation. The cycle of the engine 20 using ammonia fuel operates very similarly to the diesel cycle. In the diesel cycle, fuel is burned to produce power through the compression and ignition processes, and exhaust gas is discharged in the exhaust process. Therefore, if ammonia is supplied to the exhaust process via the engine 20's fuel supply unit 110, the ammonia will not be burned and will be discharged as is along with the exhaust gas. As a result, ammonia can be additionally supplied to the catalyst layer 35 as a reducing agent.

[0047] However, the control unit 140, which controls the supply of additional ammonia to the engine 20 via the fuel supply unit 110 during the exhaust process in which no fuel combustion occurs during the operation of the engine 20, is a configuration that can be applied to any engine 20 that uses ammonia as fuel. Therefore, even if the nitrogen oxide concentration sensor 130 or catalyst layer 35 described above is omitted, it can be independently applied to an engine 20 that uses ammonia as fuel. The ammonia supplied here can be used as a reducing agent in a selective catalytic reduction device located downstream of the engine system 100.

[0048] The system may further include a reducing agent supply unit 120 for supplying a reducing agent for a selective catalytic reduction reaction to the catalyst layer 35. The reducing agent supply unit 120 may be connected to the connecting unit 30 from the outside in the form of a nozzle. However, it is not limited to this, and may be installed in other forms that can supply a reducing agent for a selective catalytic reduction reaction to the catalyst layer 35.

[0049] The control unit 140 can control the supply of a reducing agent for the selective catalytic reduction reaction to the catalyst layer 35 via the reducing agent supply unit 120 if the nitrogen oxide concentration measured by the nitrogen oxide concentration sensor 130 exceeds a predetermined reference value. The reducing agent may include, but is not limited to, ammonia, aqueous ammonia, or aqueous urea.

[0050] Furthermore, the nitrogen oxide concentration measured by the nitrogen oxide concentration sensor 130 can be used not only to control the supply of reducing agent to the catalyst layer 35, but also to control a selective catalytic reduction device that may be located downstream of the engine system 100.

[0051] <Third Embodiment> Figure 3 shows an exhaust gas aftertreatment system according to a third embodiment of the present invention.

[0052] Referring to Figure 3, the exhaust gas aftertreatment system 200 according to the third embodiment of the present invention is located downstream of an engine 20 that uses ammonia fuel and includes a selective catalytic reduction device 210 that removes nitrogen oxides from the exhaust gas generated by the engine 20 by a selective catalytic reduction reaction, sensors 220 and 230 that measure the concentration of at least one of ammonia and nitrogen oxides contained in the exhaust gas, and a control unit 240 that adjusts the type and amount of reducing agent supplied to the selective catalytic reduction device 210 according to the concentrations of nitrogen oxides and ammonia measured by the sensors 220 and 230.

[0053] Conventionally, the reducing agent necessary for the selective catalytic reduction reaction was injected separately into the selective catalytic reduction device 210 via equipment such as a nozzle. However, since the exhaust gas emitted from the engine 20 using ammonia as fuel may contain unburned ammonia, the efficiency can be increased by adjusting the type and amount of the reducing agent injected separately. The control of reducing agent supply will be described in detail below.

[0054] The pre-stage sensor 220 is positioned between the engine 20 and the selective catalytic reduction unit 210 and can measure the concentrations of ammonia and nitrogen oxides contained in the exhaust gas emitted from the engine 20. The control unit 240 can increase the supply of the reducing agent if the amount of ammonia measured by the pre-stage sensor 220 is less than the amount of ammonia needed to remove nitrogen oxides to the maximum extent. Conversely, if the amount of ammonia measured by the pre-stage sensor 220 is sufficient to remove nitrogen oxides to the maximum extent, the control unit 240 can decrease the supply of the reducing agent.

[0055] The downstream sensor 230 is positioned downstream of the selective catalytic reduction device 210 and can measure the concentration of nitrogen oxides contained in the exhaust gas that has passed through the selective catalytic reduction device 210. The control unit 240 can increase the supply amount of reducing agent if it determines that the catalytic reaction in the selective catalytic reduction device 210 is not being carried out to the maximum extent, based on the ammonia concentration and nitrogen oxide concentration measured by the downstream sensor 230. In addition, if the ammonia concentration measured by the downstream sensor 230 is higher than a predetermined value, the control unit 240 can decrease the supply amount of reducing agent.

[0056] By utilizing the concentrations of ammonia and nitrogen oxides measured by the upstream sensor 220 and the downstream sensor 230, the difference in ammonia and nitrogen oxide concentrations before and after the selective catalytic reduction device 210 can be determined, and information can be obtained regarding the extent to which the reaction has occurred in the selective catalytic reduction device 210. If the control unit 240 determines that the reaction has not occurred sufficiently in the selective catalytic reduction device 210, it can control the supply of the reducing agent to increase. Conversely, if it determines that the reaction has occurred sufficiently in the selective catalytic reduction device 210, it can control the supply of the reducing agent to decrease.

[0057] The types of reducing agents mentioned above can include ammonia, aqueous ammonia, and aqueous urea. Since the components and concentrations differ for each type of reducing agent, the amount of reducing agent injected to remove nitrogen oxides may vary. Therefore, the control unit 240 can control the supply of different types of reducing agents, even when removing the same amount of nitrogen oxides. Furthermore, the type of reducing agent can be changed depending on the amount of unburned ammonia.

[0058] <Fourth Embodiment> Figure 4 shows an exhaust gas aftertreatment system according to the fourth embodiment of the present invention.

[0059] The system may include a plurality of selective catalytic reduction devices 210, each positioned downstream of a plurality of engines 20 using different fuels, which remove nitrogen oxides from the exhaust gas generated by the engines 20 through a selective catalytic reduction reaction, and a control unit 250 that adjusts the type and amount of reducing agent supplied to the plurality of selective catalytic reduction devices 210, each positioned downstream of the plurality of engines 20, according to the type of fuel used by the plurality of engines 20.

[0060] Depending on the type of fuel injected into the engine 20, the types and proportions of substances contained in the exhaust gas generated by each engine 20 may differ. Specifically, even with the same engine load or the same amount of fuel, different types of fuel may result in differences in the amount of nitrogen oxides contained in the exhaust gas, whether or not it contains ammonia, etc. Therefore, the control unit 250 can control the amount and type of reducing agent supplied to the selective catalytic reduction device 210 located downstream of each engine 20 to differ depending on the type of fuel supplied to the engine 20.

[0061] The control unit 250 calculates the amount of nitrogen oxides or ammonia emitted and the amount of reducing agent required to reduce nitrogen oxides according to the type of fuel supplied, the amount of fuel, and the load of the engine 20, and can automatically control the type and amount of reducing agent supplied to the selective catalytic reduction device 210 according to the fuel supply status of each engine 20.

[0062] Furthermore, the vessel may include an engine system 100, exhaust gas aftertreatment systems 10, 200 according to one embodiment of the present invention.

[0063] The above description is merely illustrative of the technical concept of the present invention, and any person with ordinary skill in the art to which the present invention pertains can make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed herein are for illustrative purposes only, and not to limit the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by such embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical concepts within an equivalent scope should be interpreted as being included within the scope of the rights of the present invention.

Claims

1. Engines that use ammonia fuel, A gas receiver is positioned downstream of the engine and contains the exhaust gas generated by the engine, The engine and the gas receiver are connected, and the connection part includes a part through which exhaust gas generated by the engine is discharged to the gas receiver. The connecting portion is provided with a catalyst layer in the part through which the exhaust gas passes. The catalyst layer is either a selective catalytic reduction layer in which ammonia in the exhaust gas acts as a reducing agent to carry out a selective catalytic reduction (SCR) reaction and remove nitrogen oxides, or An engine system comprising a composite ammonia purification layer in which, under conditions where the exhaust gas contains ammonia and nitrogen oxides, the ammonia in the exhaust gas acts as a reducing agent to carry out a selective catalytic reduction (SCR) reaction to remove nitrogen oxides, and under conditions where the exhaust gas does not contain nitrogen oxides, the ammonia in the exhaust gas is oxidized and removed.

2. A nitrogen oxide concentration sensor for measuring the concentration of nitrogen oxides in the exhaust gas contained in the gas receiver, The engine system according to claim 1, further comprising: a control unit that controls the supply of a reducing agent for a selective catalytic reduction reaction to the catalyst layer when the concentration of nitrogen oxides measured by the nitrogen oxide concentration sensor exceeds a predetermined reference value.

3. The engine system according to claim 2, wherein the control unit controls the engine to supply additional ammonia to the exhaust process, during which no fuel is burned during the engine's operation, via the engine's fuel supply unit, if the nitrogen oxide concentration measured by the nitrogen oxide concentration sensor exceeds a predetermined reference value.

4. The system further includes a reducing agent supply unit that supplies a reducing agent for a selective catalytic reduction reaction to the catalyst layer, The engine system according to claim 2, wherein the control unit controls the supply of a reducing agent for a selective catalytic reduction reaction to the catalyst layer via the reducing agent supply unit when the concentration of nitrogen oxides measured by the nitrogen oxide concentration sensor exceeds a predetermined reference value.

5. Engines that use ammonia fuel, An engine system including a control unit that controls the supply of additional ammonia to the engine via the engine's fuel supply unit during the exhaust process in which no fuel is burned during the engine's operation.

6. A ship comprising the engine system according to any one of claims 1 to 5.

Images