Apparatus and method for burning purge gas

Abstract

An apparatus (100) and method for combusting purge gas resulting from an ammonia fuel system (108) that fuels an ammonia-fueled engine (112), the apparatus (100) comprising a burner (104), a fuel inlet (111) configured to supply fuel thereby maintaining a support flame in the burner (104), and a purge gas inlet (121) configured to intermittently receive purge gas from the ammonia-fueled engine (112) and supply the purge gas to the burner (104), the purge gas comprising a mixture of ammonia and an inert gas, the burner (104) comprising a boiler system (102) configured to combust ammonia in the support flame.

Description

Technical Field

[0001] The present disclosure relates to an apparatus and method for combusting purge gas generated from an ammonia fuel system that supplies fuel to an ammonia fuel engine.

Background Art

[0002] Marine engines powered by oil or gas are well known in the art. Oil and gas-fired boilers for marine steam production are also well known in the art. Usually, the selection of fuel for boiler operation is made in relation to the fuel selected for marine engine operation. Therefore, when a marine engine is powered by oil, the boiler is often similarly powered by oil. However, the marine engine and the boiler may be powered by different fuels.

[0003] One drawback regarding most of today's marine engines is marine air pollution, particularly carbon dioxide (CO2) emitted from marine engines when providing propulsion. It is generally agreed that CO2 emissions, as well as other greenhouse gas emissions, must be reduced in view of environmental aspects. As a solution, alternative fuels are gaining traction in the maritime industry. This includes fuels such as methanol, hydrogen, ammonia or the conversion of biomass. However, by introducing alternative fuels, other problems, such as other environmental problems, may arise. For example, by powering a marine engine with some alternative fuels, the gases resulting from those fuels, for example often, for example due to toxicity, must not be directly released into the atmosphere and often need to be removed before being released into the atmosphere. The latter applies, for example, when ammonia is used as a fuel. Therefore, although alternative fuels may be environmentally friendly with respect to greenhouse gas emissions compared to conventional fuels, there are further other problems that need to be overcome.

[0004] In an attempt to address some of these problems, Document CN109140496 discloses a boiler ignition device that uses ammonia purge gas as a heat source and includes a purge gas supply pipeline and an ignition gas supply pipeline.

[0005] However, as will be explained below, the prior art does not disclose a more environmentally friendly marine device that can appropriately address a set of design criteria that enable the use of alternative fuels while ensuring that no or only limited amounts of toxic gases are released into the atmosphere. In particular, the prior art does not disclose a way to provide an entire device that can be easily used over time with respect to meeting the above set of design criteria.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] The object of the present disclosure is to provide a more environmentally friendly marine device that can appropriately address a set of design criteria that enable the use of alternative fuels while ensuring that no or only limited amounts of toxic gases are released into the atmosphere.

Means for Solving the Problems

[0008] This object is achieved by a device for burning purge gas generated from an ammonia fuel system that supplies fuel to an ammonia fuel engine. The device includes a burner, a fuel inlet configured to supply fuel and thereby maintain a supporting flame for the burner, configured to intermittently receive purge gas from an ammonia fuel system and supply the purge gas to a burner, the purge gas inlet being provided, wherein the purge gas contains a mixture of ammonia and an inert gas configured such that the burner burns ammonia with a pilot flame comprising a boiler system

[0009] Preferably, the ammonia fuel engine is a marine engine. The ammonia fuel engine is advantageous because it uses ammonia, a fuel that is environmentally friendly for operating the engine, as compared with most of the fossil fuels, such as oil and gas, that are used today. The present apparatus is advantageous because it burns the purge gas instead of discharging the purge gas generated from the ammonia fuel system to the atmosphere. The purge gas can be generated when the ammonia fuel engine switches the fuel from ammonia to another fuel, or when the ammonia fuel engine stops, either in a controlled manner or as a result of an emergency situation. At this stage, the purge gas is toxic and should not be discharged to the atmosphere. Instead, the purge gas inlet receives the purge gas generated from the ammonia fuel system and supplies the purge gas to the burner. By burning the mixture in the burner, the purge gas is discharged to the atmosphere as combustion gas mainly composed of nitrogen and water instead of as a toxic gas. Therefore, it can be said that the present apparatus acts as a safety mechanism by burning the purge gas with the burner instead of discharging toxic gas to the atmosphere. Therefore, a more environmentally friendly marine apparatus is achieved that uses an alternative fuel, i.e., ammonia, while preventing any toxic gas from being discharged to the atmosphere or minimizing such discharge.

[0010] Preferably, the ammonia fuel engine is operating with ammonia in pure form. However, it should be noted that ammonia may contain a trace amount of water. It should further be noted that ammonia may be mixed with another fuel, such as an alcohol like methanol or ethanol, or a gas like hydrogen. Mixing ammonia with another fuel may be advantageous if it is too difficult to burn ammonia with a pilot flame.

[0011] The purge gas may contain a mixture of ammonia and an inert gas. The inert gas may be nitrogen. Preferably, the nitrogen is compressed nitrogen. However, it should be noted that other inert gases may be used as well. It should further be noted that if ammonia is mixed with another fuel, the purge gas will likewise contain other fuels. The fuel may initially be supplied to provide a pilot flame and may also be supplied as the main fuel when the burner is operating in the operating mode. When the fuel is supplied to provide a pilot flame, the fuel may be in a small amount so that a small flame for ignition of the main fuel can be provided. The pilot flame may be for igniting the fuel supplied as the main fuel. When the fuel is supplied as the main fuel, the fuel is supplied in a large amount as compared with the fuel supplied to provide a pilot flame. Preferably, when burning ammonia, the main fuel acts as a support flame so that the purge gas burns with the support flame. The support flame must be of a certain size to ensure complete combustion of ammonia.

[0012] Preferably, when the boiler is started to burn the purge gas, the boiler can maintain a support flame by supplying fuel at a rate of 15-50%, preferably 25-50%, compared to the rate at which fuel is supplied when the boiler is operating at full capacity. In this sense, it can operate at 15-50%, preferably 25-50%, compared to full capacity, so that the burner is started for the purpose of burning the purge gas and when it is started to produce heat and does not operate at full capacity, it ensures that the ammonia supplied to the burner is burned. It should be noted that in this context, heat production may refer to steam production, heating hot water, heating a heat transfer fluid, or heating any other medium used in the boiler. Since the purge gas is typically more difficult to ignite compared to the main fuel, the support flame typically must be larger than the pilot flame. The fuel inlet and the purge gas inlet may be separate inlets. However, as will be further described below, if the purge gas includes both gas and liquid, the liquid may be supplied to the burner through the fuel inlet and the gas may be supplied to the burner through the purge gas inlet.

[0013] The burner may be of the steam atomization type or the pressure atomization type. It should be noted that when the burner is of the steam atomization type, fuel may be supplied to provide a pilot fuel for igniting the main fuel. When the burner is of the pressure atomization type, the fuel is typically only supplied as the main fuel. Instead, the pressure atomizing burner is equipped with a spark igniter configured to ignite the main fuel. However, when the burner is of the steam atomization type, the fuel may be supplied to provide a pilot flame as a spark igniter for igniting the main fuel.

[0014] The boiler system may be configured to operate in at least one of a first mode and a second mode. The first mode is a heat production mode in which heat is produced. The second mode is an ammonia safety purge mode in which the boiler is kept warm and ready for high-speed operation and / or the pilot flame is maintained.

[0015] The first mode may be the operation mode described above. The second mode may be a preparation mode, in which the boiler is ready for high-speed operation or ready for a quick start. In the first and second modes, the burner may be an active burner. By the term "active burner", here is meant a burner that is always ready to receive purge gas through the purge gas inlet since the shutdown of the engine can occur at any time. If the burner is an active burner, the burner is in the operation mode or in the preparation mode where it is ready to receive purge gas.

[0016] The disclosed boiler system provides for achieving a more flexible boiler system. By having a more flexible boiler system, it is possible to use the boiler system in more ways than just for the main purpose of the burner, i.e., producing heat. The boiler system may thus also be configured to burn purge gas. It provides for the conventional burner, for example an oil burner or a gas burner, to be used for producing heat as well as for burning purge gas in case of switching between different modes. However, it should be noted that the burner may be configured to operate in more than two modes.

[0017] The boiler system may be configured to operate in at least one of a first sub-mode and a second sub-mode of the first mode. In the first sub-mode, a main flame is maintained at the burner for heat production and purge gas is not supplied to the burner. In the second sub-mode, a main flame is maintained at the burner for heat production and purge gas is supplied to the burner so that ammonia burns in the main flame acting as a support flame.

[0018] The first sub-mode of the first mode may be configured to produce heat from the main fuel. The second sub-mode of the first mode may be configured to produce heat from the main fuel and the purge gas, thereby burning the purge gas.

[0019] The boiler system may be configured to ignite the support flame by first igniting a pilot flame and then igniting the support flame from the pilot flame, or, if the pilot flame is maintained, directly igniting the support flame from the pilot flame, and to supply purge gas to the burner to burn ammonia in the support flame.

[0020] Preferably, each inlet may be controlled by one or more valves. The one or more valves may be configured to open and close the fuel inlet and the purge gas inlet such that switching between at least two modes and / or between a first and a second sub-mode of a first mode is possible. The one or more valves may be configured to open and close the fuel inlet independently and to open and close the purge gas inlet independently.

[0021] The fuel inlet may be connected to a fuel source via a fuel supply line, and the fuel source may be configured to supply a fuel selected from the group consisting of liquefied natural gas (LNG), distillate oil, and residual fuel. This may include, for example, diesel, marine gas oil (MGO), very low sulfur fuel oil (VLSFO), and heavy fuel oil (HFO). The fuel may also be a biofuel. It should be noted that other types of fuels such as ammonia, hydrogen, and methanol may also be used as fuels. It should be noted that the fuel may include two types of fuels. The two types of fuels may be pre-mixed with each other and supplied from the same fuel source, or may be kept separately and supplied from two different fuel sources. The fuel source may be, for example, a tank. When the fuel includes two types of fuels and is supplied from two different fuel sources, they may each have one supply line from their respective fuel tanks to the burner, but they may also be shared. When the two types of fuels are supplied from two different fuel sources each having a supply line, they may each also have a fuel inlet, or alternatively, there is one fuel inlet connected to two different supply lines so that the fuels from the two different fuel sources can be fed into the burner through a common inlet. The other fuel source may be configured to supply a fuel selected from the group consisting of liquefied natural gas (LNG), distillate oil, and residual fuel. This may include, for example, diesel, marine gas oil (MGO), very low sulfur fuel oil (VLSFO), and heavy fuel oil (HFO). The fuel may also be a biofuel. It should be noted that other types of fuels such as ammonia, hydrogen, and methanol may also be used as fuels.

[0022] The apparatus may further comprise an ammonia fuel system, and the ammonia fuel system includes an ammonia fuel source for storing ammonia, a fuel supply system, an ammonia fuel engine, and a purge source containing an inert gas and configured to purge ammonia from a portion of the ammonia fuel system to a purge gas inlet by flushing the inert gas through the portion of the ammonia fuel system.

[0023] This is advantageous as it ensures that there is no unwanted fuel in the ammonia fuel system pipelines. Therefore, when the ammonia fuel engine switches or shuts down, as described above, ammonia that should not be released to the atmosphere or returned to the ammonia fuel source for supply can be present in the pipelines. By flushing an inert gas through those parts of the ammonia fuel system, the ammonia that can remain in the pipelines is pushed out of the ammonia fuel system to form a mixture of ammonia and inert gas, and this mixture can be directed towards the boiler system. The mixture may be directed through an evaporator and / or a separator to account for the fact that, for example, a mixture of ammonia and inert gas can also be a gas-liquid phase mixture. By pushing ammonia out of the ammonia fuel system with an inert gas, more or less all of the ammonia is released from the ammonia fuel system in preparation. Thereby, a safer and more environmentally friendly device is achieved.

[0024] Ammonia may be purged from parts of the ammonia fuel system. Preferably, ammonia may be purged from parts close to the engine as it can be contaminated ammonia within those parts close to the engine, and mixing contaminated ammonia back into the ammonia fuel source should be avoided.

[0025] Preferably, the ammonia pushed out of the ammonia fuel system should be pushed out of the system rather than being forced into other parts within the ammonia fuel system. The ammonia fuel system may comprise one or more valves configured to control the flow of ammonia when ammonia is being pushed out of the ammonia fuel system.

[0026] The apparatus may further comprise a fuel valve train and recirculation for handling ammonia that does not need to be purged. This can be ammonia, for example, present in parts of the ammonia fuel system that are typically relatively close to the fuel tank. Such ammonia typically does not take in much dirt and water and may typically be returned to the fuel tank.

[0027] The mixture of ammonia and inert gas may include gaseous ammonia, liquid ammonia, and inert gas.

[0028] The apparatus may further comprise an evaporator configured to evaporate liquid ammonia into gaseous ammonia, thereby providing a gaseous mixture of ammonia and inert gas that will be supplied to the burner. It is typical that a mixture containing both liquid ammonia and gaseous ammonia is not optimal for the burner. Therefore, the burner typically requires either liquid or gas, but typically does not function well with a mixture of both. Thus, if the mixture can contain both liquid and gas, it may need to be converted to either liquid or gas. By introducing an evaporator into the apparatus, it may be possible to evaporate liquid ammonia into gaseous ammonia such that the purge supplied to the burner can only contain purge gas. Therefore, the evaporator may be advantageous in that it prepares for the case where only the gas purge is accepted by the burner. Preferably, the evaporator is arranged to be supplied to the evaporator before the purge gas is supplied to the purge gas inlet.

[0029] The apparatus may further or alternatively comprise a separator configured to separate liquid ammonia from gaseous ammonia and inert gas, thereby providing a gaseous mixture of ammonia and inert gas that will be supplied to the burner. By introducing a separator into the apparatus, it may be possible to separate liquid ammonia from gaseous ammonia and inert gas such that the purge supplied to the burner can only contain purge gas. The separator may be a gas-liquid separator, typically a drum or tank with a demister at the outlet. The liquid phase of the purge may be connected to the main fuel supply system such that the liquid phase is mixed with the liquid main fuel. It should be noted that the apparatus may comprise either an evaporator, a separator, or only one of them.

[0030] The evaporator may be arranged downstream of the separator such that, for example, the purge gas from which most of the liquid phase has been removed in the separator is supplied to the evaporator before being supplied to the purge gas inlet.

[0031] The burner may be a multi-fuel burner configured to burn at least two different fuels one by one or simultaneously. This is advantageous in that two or more fuels may be configured to move the burner or be burned by the burner. The multi-fuel burner may be configured to burn at least two different fuels, preferably two different liquid fuels, preferably one by one. The multi-fuel burner may be configured to burn one or more liquid fuels in combination with burning one or more gaseous fuels, and one or more gaseous fuels, preferably the gaseous fuels are burned one by one while one or more liquid fuels, preferably the liquid fuels are burned one by one.

[0032] The apparatus may further comprise a liquid ammonia inlet connected via a liquid ammonia connection to the fuel supply line such that liquid ammonia is mixed with the fuel. This may be advantageous if the apparatus comprises a separator and / or an evaporator. In this case, the liquid ammonia separated from the purge gas may be mixed with the fuel and configured to reach the burner in a different mixture compared to the purge gas mixture.

[0033] The apparatus may further comprise a combustion fan configured to provide combustion air to the burner. The combustion fan may be configured to supply a specific amount of combustion air based on preset requirements. Preferably, there should be 10 - 15% more combustion air than fuel in the boiler system. This ratio of combustion air is typically required for complete combustion of the fuel as well as the purge gas. If the combustion is not complete, it can lead to a fouled furnace and black exhaust gas with a higher carbon monoxide CO content than required.

[0034] The device may further comprise a gas valve train configured to control the flow of purge gas supplied from an ammonia fuel system to the burner.

[0035] The combustion fan may be further or alternatively configured to direct purge gas to the burner. The combustion fan may comprise a purge gas inlet, and the combustion fan may be configured to mix the purge gas with combustion air and to provide a mixture of purge gas and combustion air to the burner.

[0036] When the combustion fan is configured to direct purge gas to the burner, the gas valve train may be excluded from the device. Instead, the combustion fan may be arranged to control and direct the flow of purge gas supplied from an ammonia fuel system to the burner. In the combustion fan, the purge gas may be mixed with combustion air. The mixture may be directed to the burner and the mixture may be burned with a pilot flame. However, it should be noted that the device may comprise both a combustion fan and a gas valve train for directing purge gas. The combustion fan may be designed for purge gas. The purge gas inlet provided in the combustion fan may ensure optimal mixing with combustion air. In addition, the combustion fan may be arranged to prevent backflow of the purge gas.

[0037] Furthermore, when the device comprises an evaporator and / or a separator, the combustion fan is preferably arranged downstream of the evaporator and / or the separator.

[0038] The above object is also achieved by a method for burning purge gas resulting from an ammonia fuel system that supplies fuel to an ammonia fuel engine, the method comprising: maintaining a pilot flame in a burner provided in a boiler system, the pilot flame being maintained by fuel supplied through a fuel inlet; intermittently supplying purge gas, the purge gas being supplied from an ammonia fuel system to the burner through a purge gas inlet, the purge gas comprising a mixture of ammonia and an inert gas; It includes a step of burning ammonia in a burner with a supporting flame.

[0039] Therefore, the method includes a step of the burner receiving a purge gas from an ammonia fuel system before the ammonia is burned.

[0040] According to the method, the boiler system may be configured to operate in at least one of a first mode and a second mode. The first mode is a heat production mode in which heat is produced. The second mode is an ammonia safety purge mode in which the boiler is insulated, ready for high-speed operation, and / or a pilot flame is maintained.

[0041] The further different preferred embodiments described above with respect to the apparatus are equally applicable to the method.

[0042] The apparatus is preferably disposed on a ship. The method is preferably performed on a ship. However, it may be noted that neither the apparatus nor the method is limited to being used on a ship. The apparatus and the method may be useful for other applications where an engine and a boiler are located near each other. This may be applicable, for example, to other marine applications separate from a ship. It may be a platform such as the type used for drilling for oil or gas. The apparatus and method may also be useful for land-based applications. The apparatus and method may be used, for example, for logging or mining applications.

[0043] In general, all terms used in the claims will be construed according to their ordinary meaning in the art, unless explicitly defined otherwise herein. All references to "a / an / the [element, apparatus, component, means, step, etc.]" will be construed openly as referring to at least one example of the above element, apparatus, component, means, step, etc., unless explicitly stated otherwise. None of the steps of any method disclosed herein need to be performed in the exact order disclosed, unless explicitly stated otherwise.

[0044] In addition to the above of the present disclosure, additional objects, features, and advantages will be better understood through the following illustrative and non-limiting detailed description of the preferred embodiments of the present disclosure, with reference to the accompanying drawings in which like reference numerals will be used for like elements.

Brief Description of the Drawings

[0045]

Figure 1

Figure 2

Mode for Carrying Out the Invention

[0046] The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which presently preferred embodiments of the present disclosure are shown. The present disclosure, however, may be embodied in many different forms and should not be construed as limited to the embodiments disclosed herein. Rather, these embodiments are provided for thoroughness and completeness and to fully convey the scope of the present disclosure to those skilled in the art.

[0047] Referring to FIG. 1, an apparatus 100 for burning purge gas generated from an ammonia fuel system 108 that supplies fuel to an ammonia fuel engine 112 is disclosed. The apparatus 100 includes a boiler system 102 and an ammonia fuel system 108. The ammonia fuel system 108 includes an ammonia fuel engine 112.

[0048] The purge gas can be generated in a controlled manner or as a result of an emergency situation, when the ammonia fuel engine 112 switches fuel from ammonia to another fuel, or when the ammonia fuel engine 112 stops. At this stage, the purge gas is toxic and therefore should not be released into the atmosphere. The purge gas is typically a mixture of ammonia and an inert gas used to purge ammonia from the ammonia fuel system 108. The ammonia may be liquid ammonia, gaseous ammonia, or a mixture thereof. The inert gas may be nitrogen. It should be noted that the inert gas may be any other inert gas.

[0049] The boiler system 102 includes a burner 104, a fuel inlet 111, and a purge gas inlet 121. The burner 104 is configured to burn the purge gas generated from the ammonia fuel system 108. In other words, the burner 104 is configured to burn the ammonia in the purge gas. The burner 104 may be a multi-fuel burner configured to burn two different fuels one by one or simultaneously. The burner 104 may be a pressure spray type. The burner 104 may alternatively be a steam spray type.

[0050] The fuel inlet 111 is configured to supply fuel and thereby maintain a pilot flame for the burner 104. The fuel inlet 111 is typically configured to supply fuel continuously, at least in the sense that it is capable of maintaining a pilot flame. The fuel may be supplied initially to provide a pilot flame and may also be supplied as the main fuel when the burner is operating in the operating mode. The main fuel may act as a pilot flame so that the purge gas can be burned with a pilot flame.

[0051] The purge gas inlet 121 is preferably separated from the fuel inlet 111. The purge gas inlet 121 is configured to intermittently receive purge gas from the ammonia fuel system 108 and supply the purge gas to the burner 104. The purge gas may be supplied from the ammonia fuel system 108 to the purge gas inlet 121 via the purge gas pipe 123. The pipe 123 may be of a double-wall type, particularly for the portion of the pipe 123 where the purge is in the gas phase.

[0052] The fuel inlet 111 may be connected to a fuel source 115, such as a fuel tank, via a fuel supply line 113. The fuel source 115 is configured to supply fuel to the burner 104 via the fuel inlet 111. The fuel may be liquefied natural gas (LNG), distillate oil, and residual fuel. This may include, for example, diesel, marine gas oil (MGO), very low sulfur fuel oil (VLSFO), heavy fuel oil (HFO). The fuel may also be biofuel. However, it should be noted that the main fuel may also be other fuels. The fuel may include one or more types of fuel. When the fuel includes two or more types of fuel, the fuel inlet 111 may be connected to two or more fuel sources. Therefore, when the fuel includes two types of fuel, one fuel type may be supplied from the fuel source 115, and the other fuel type may be supplied from another fuel source 135. Typically, the fuel is supplied to the burner 104 one by one. Typically, the fuel supply line 113 operates in such a way that, as illustrated in FIG. 1, different fuels are provided one by one using the same inlet 111 at different times. One possible combination is to provide liquid fuel to the inlet 111 via the fuel supply line 113 and simultaneously provide gas via a separate gas inlet, such as via the combustion fan 120. The gas provided via a separate gas inlet such as the combustion fan 120 may be purge gas and / or it may be a gaseous fuel that does not result from a purge operation.

[0053] However, as illustrated in FIG. 1, the fuel supply line 113, if so desired, may be used to mix two types of fuel in the fuel supply line 113, and the other fuel may be supplied to the fuel supply line 113 by another one of the fuel supply lines 133, such that the mixture is supplied to the burner 104 via the fuel inlet 111. However, although not illustrated, the two types of fuel may be supplied to the burner 104 by two different fuel inlets via two different supply lines. Thus, the apparatus 100 may comprise an additional supply line disposed separately from the fuel supply line 113, and the additional supply line may be arranged to supply the other fuel from the other fuel source 135 to the burner 104. The other fuel may be any of the fuels listed above with respect to the fuel. Preferably, when the fuel comprises two types of fuel, one type may be a liquid fuel and the other type may be a gaseous fuel.

[0054] Referring to FIG. 2, a flowchart 200 is shown by way of example, illustrating a method 200 for the combustion of purge gas resulting from an ammonia fuel system 108 that supplies fuel to an ammonia fuel engine 112. The boiler system 102 is configured to operate in a first mode 201. The boiler system 102 is configured to operate in a second mode 211. The boiler system 102 may be configured to operate in a mode different from the first mode 201 and the second mode 211. The first mode 201 may be a heat production mode in which heat is produced. It may be noted in this context that the production of heat may refer to the production of steam, heating hot water, heating a heat transfer fluid, or heating any other medium used in the boiler. The second mode 211 may be an ammonia safety purge mode in which the boiler 106 is kept warm and ready for high-speed operation and / or a pilot flame is maintained. The boiler 106 is provided in the boiler system 102. In the second mode 211, the boiler may be ready for high-speed operation or ready for a high-speed start-up.

[0055] The boiler system 102 may be configured to operate in a first sub-mode 201a and a second sub-mode 201b of a first mode 201. In the first sub-mode 201a, the main flame is maintained at the burner 104 for heat production, and the purge gas is not supplied to the burner 104. The first sub-mode 201a is configured to produce heat from the fuel supplied to the burner 104 through the fuel inlet 111. The second sub-mode 201b of the first mode 201 is configured to produce heat from the main fuel and the purge gas, and the purge gas is supplied through the purge gas inlet 121. Therefore, in the second sub-mode 201b, the main flame is maintained at the burner 104 for heat production, and the purge gas is supplied to the burner 104. Ammonia is burned in the main flame that acts as a supporting flame.

[0056] The boiler system 102 is configured to ignite the supporting flame by first igniting the pilot flame or the pilot spark and then igniting from the pilot flame to the supporting flame. When the pilot flame is maintained, the boiler system 102 is configured to directly ignite from the pilot flame to the supporting flame and supply the purge gas to the burner 104 to burn ammonia in the supporting flame.

[0057] Therefore, both the first mode and the second mode are configured to burn ammonia, although starting from different points.

[0058] Referring back to FIG. 1, the ammonia fuel system 108 includes an ammonia fuel source 155, a fuel supply system 110, and an ammonia fuel engine 112. The ammonia fuel system 108 may include a purge source 165. The ammonia fuel source 155 may be an ammonia tank and is configured to store ammonia before being supplied to the ammonia fuel engine 112. The fuel supply system 110 is configured to supply ammonia within the ammonia fuel system 108. The ammonia fuel engine 112 is configured to be driven by the ammonia supplied from the ammonia fuel source 155.

[0059] The purge source 165 is a gas tank that typically contains an inert gas. The inert gas from the purge source 165 is configured to purge ammonia from the ammonia fuel system 108 to the purge gas inlet 121 by flushing the inert gas through the ammonia fuel system 108. The apparatus 100 may include a gas valve train 118 configured to control the flow of the purge gas supplied from the ammonia fuel system 108 to the burner 104. As described above, the purge gas is a mixture of ammonia and an inert gas. The ammonia may be liquid ammonia, gaseous ammonia, or a mixture thereof. When the ammonia is a mixture of gaseous ammonia and liquid ammonia, the purge gas is a mixture of gas and liquid. The purge gas supplied to the burner 104 should be in gas form, and thus the liquid must be removed from the purge gas before being supplied to the burner 104.

[0060] The apparatus 100 may include an evaporator 114 configured to evaporate liquid ammonia to gaseous ammonia if present in the mixture. By evaporating liquid ammonia to gaseous ammonia, a gaseous mixture of ammonia and an inert gas may be supplied to the burner 104. The evaporator 114 may be disposed within the purge gas piping 123 between the boiler system 102 and the ammonia fuel system 108.

[0061] The apparatus 100 may further or alternatively include a separator 116 configured to separate liquid ammonia from gaseous ammonia and an inert gas if present in the mixture. By separating liquid ammonia from gaseous ammonia and an inert gas, a gaseous mixture of ammonia and an inert gas may be supplied to the burner 104. The separator 116 may be disposed within the purge gas piping 123 between the boiler system 102 and the ammonia fuel system 108.

[0062] It should be noted that the apparatus 100 may include either the evaporator 114, the separator 116, or only one of the evaporator 114 and the separator 116.

[0063] The apparatus 100 may include a liquid ammonia inlet 141. The liquid ammonia inlet 141 may be connected to the fuel pipe 133 via a liquid ammonia pipe 143. The liquid ammonia inlet 141 may be configured to supply liquid ammonia from the evaporator 114 and / or the separator 116 to the fuel pipe 133 such that the liquid ammonia is mixed with the fuel disposed in the fuel pipe 133. Thus, the liquid ammonia may be supplied to the burner 104 as a mixture with the fuel.

[0064] The apparatus 100 may include a combustion fan 120. The combustion fan 120 may be configured to provide air to the burner 104 for the combustion of ammonia. The combustion fan 120 may be configured to supply a specific amount of air based on preset requirements. The combustion fan 120 may be further or alternatively configured to direct purge gas to the burner 104. The combustion fan may be further or alternatively configured to direct purge gas to the burner. The combustion fan 120 may include a purge gas inlet 121, and the combustion fan 120 may be configured to mix the purge gas with the combustion air. The combustion fan 120 may be further arranged to direct a mixture of purge gas and combustion air to the burner 104. Those skilled in the art will recognize that the present disclosure is in no way limited to the preferred embodiments described above. On the contrary, many modifications and changes are possible within the scope of the appended claims.

Description of Reference Numerals

[0065] 100 Apparatus 102 Boiler System 104 Burner 106 Boiler 108 Ammonia Fuel System 110 Fuel Supply System 111 Fuel Inlet 112 Ammonia Fuel Engine 113 Fuel Supply Line 114 Evaporator 115 Fuel Source 116 Separator 118 Gas Valve Train 120 Combustion Fan 121 Purge Gas Inlet 123 Purge Gas Pipe 133 Fuel Supply Line 135 Fuel Source 141 Liquid Ammonia Inlet 143 Liquid Ammonia Pipe 155 Ammonia Fuel Source 165 Purge Source

Claims

1. An apparatus (100) for burning purge gas generated from an ammonia fuel system (108) that supplies fuel to an ammonia fuel engine (112), comprising: a burner (104); a fuel inlet (111) configured to supply fuel and thereby maintain a supporting flame in the burner (104); a purge gas inlet (121) configured to intermittently receive purge gas from the ammonia fuel system (108) and supply the purge gas to the burner (104), the purge gas including a mixture of ammonia and an inert gas; a boiler system (102) including the above; The apparatus (100), wherein the burner (104) is configured to burn the ammonia with the supporting flame.

2. The boiler system (102) is configured to operate in at least one of a first mode (201) and a second mode (211), the first mode (201) being a heat production mode in which heat is produced, the second mode (211) being an ammonia safety purge mode in which the boiler (106) is kept warm and ready for high-speed operation and / or a pilot flame is maintained, and the boiler system (102) is configured to ignite the supporting flame by first igniting the pilot flame and then igniting the supporting flame from the pilot flame, or directly igniting the supporting flame from the pilot flame when the pilot flame is maintained, and configured to supply purge gas to the burner (104) to burn the ammonia with the supporting flame. The apparatus (100) according to claim 1.

3. The boiler system (102) is configured to operate in at least one of a first sub-mode (201a) and a second sub-mode (201b) of the first mode (201). In the first sub-mode (201a), a main flame is maintained in the burner (104) for heat production and no purge gas is supplied to the burner (104). In the second sub-mode (201b), the main flame is maintained in the burner (104) for heat production and purge gas is supplied to the burner (104) so that the ammonia is burned with the main flame acting as the supporting flame. The apparatus (100) according to claim 2.

4. The apparatus (100) according to any one of claims 1 to 3, wherein the fuel inlet (111) is connected to a fuel source (115, 135) via a fuel supply line (113, 133), and the fuel source (115, 135) is configured to supply the fuel selected from the group consisting of liquefied natural gas (LNG), distillate oil, and residual fuel.

5. The apparatus (100) according to any one of claims 1 to 4, further comprising the ammonia fuel system (108), the ammonia fuel system (108) comprising an ammonia fuel source (155) for storing ammonia, a fuel supply system (110), the ammonia fuel engine (112), and a purge source (165) containing the inert gas and configured to purge ammonia from the ammonia fuel system (108) to the purge gas inlet (121) by flushing the inert gas through the ammonia fuel system (108).

6. The apparatus (100) according to any one of claims 1 to 5, wherein the mixture of ammonia and inert gas comprises gaseous ammonia, liquid ammonia, and an inert gas.

7. The apparatus (100) according to claim 6, further comprising an evaporator (114) configured to evaporate liquid ammonia into gaseous ammonia, thereby providing a gaseous mixture of ammonia and inert gas to be supplied to the burner (104).

8. The apparatus (100) according to claim 6 or 7, further comprising a separator (116) configured to separate the liquid ammonia from the gaseous ammonia and inert gas, thereby providing a gaseous mixture of ammonia and inert gas to be supplied to the burner (104).

9. The burner (104) is configured to burn at least two different fuels, one by one or simultaneously, or to burn one or more liquid fuels in combination with burning one or more gaseous fuels and is a multi-fuel burner. The apparatus (100) according to any one of claims 1 to 8.

10. Further comprising a combustion fan (120), wherein the combustion fan (120) comprises the purge gas inlet (121), and the combustion fan (120) is configured to mix the purge gas with combustion air and provide a mixture of the purge gas and combustion air to the burner (104), the apparatus (100) according to any one of claims 1 to 9.

11. The apparatus (100) according to any one of claims 1 to 10, wherein the inert gas is nitrogen.

12. A method (200) for burning purge gas generated from an ammonia fuel system (108) that supplies fuel to an ammonia fuel engine (112), comprising: Maintaining a pilot flame in a burner (104) provided in a boiler system (102), the pilot flame being maintained by fuel supplied through a fuel inlet (111); Intermittently supplying the purge gas, the purge gas being supplied from the ammonia fuel system (108) to the burner (104) through a purge gas inlet (121), the purge gas comprising a mixture of ammonia and an inert gas; Burning the ammonia in the burner (104) with the pilot flame.

13. The boiler system (102) is configured to operate in at least one of a first mode (201) and a second mode (211), The first mode (201) is a heat production mode in which heat is produced, The second mode (211) is an ammonia safety purge mode in which the boiler is kept warm and ready for high-speed operation and / or a pilot flame is maintained, and the boiler system (102) Ignites the pilot flame and then ignites the support flame from the pilot flame, or directly ignites the support flame from the pilot flame when the pilot flame is maintained, and Is configured to supply purge gas to the burner (104) to burn the ammonia with the support flame, the method (200) according to claim 12.

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