Ammonia collection system

Abstract

The present invention relates to an ammonia collection system in which ammonia and nitrogen are separated stepwise through a re-distillation process using a high-temperature separation drum and a packing column unit, and recycled or safely discharged into the atmosphere in a high-purity state, respectively, thereby enabling efficient ammonia separation and recycling.

Description

Ammonia capture system

[0001] The present invention relates to an ammonia capture system, and more specifically, to an ammonia capture system that enables efficient ammonia separation and recycling by separating ammonia and nitrogen in stages through a re-condensation process using a room-temperature separation drum and packing column section and a low-temperature re-condensation device, and by recycling them in a high-purity state or safely discharging them into the atmosphere.

[0002] Generally, an ammonia (NH3) fuel supply system is designed to supply ammonia at controlled temperatures and pressures to meet engine demands, operating under relatively low pressure conditions near atmospheric levels. Compared to LNG high-pressure gas injection systems, such systems offer the advantages of lower energy and cost consumption, as well as relatively easier technical implementation. Particularly in very large vessels (VLCCs) and medium-sized container ships, stable and precise pressure control of the boil-off gas (BOG) of ammonia is critical, requiring the maintenance of ammonia storage tanks and vapor pressure within an acceptable operating range. Additionally, a vapor reliquefaction system is installed to prevent the atmospheric release of ammonia vapor, and the design requires the separation of mixed nitrogen (N2) and ammonia (NH3) generated during fuel pipeline purge into high-purity form for release into the atmosphere.

[0003] In this context, maintaining stable vapor pressure is an essential element within ammonia storage tanks and systems; however, achieving this requires complex control mechanisms and highly precise equipment, which leads to increased design and maintenance costs. Furthermore, existing vapor reliquefaction systems used to prevent atmospheric release of ammonia vapor suffer from low efficiency and high energy consumption, posing a problem that causes maintenance difficulties in situations requiring high reliability in marine environments.

[0004] Furthermore, in conventional ammonia vapor reliquefaction systems, the separation efficiency of the ammonia and nitrogen mixture generated during fuel pipeline purge is low, causing fuel loss and air pollution. In particular, due to the difference in physical properties between nitrogen and ammonia, nitrogen does not dissolve into liquid ammonia. Consequently, nitrogen, which has a relatively high boiling point, remains mixed in the vapor region of the ammonia storage system as a mixed gas, significantly affecting the design and operation of the ammonia reliquefaction system. Moreover, reliquefaction becomes impossible if the concentration exceeds a certain level. Therefore, if nitrogen is not separated from the ammonia mixture with high purity, problems arise in the pressure control of the ammonia storage facility. For this reason, a typical vapor compression cycle cannot separate nitrogen with high purity. Consequently, nitrogen must either be released along with a large amount of ammonia or separated from ammonia through methods such as water dilution; however, this also causes the generation of contaminated water, leading to increased post-treatment costs during the design of the ship system. In addition, existing devices similar to this (compression-expansion re-liquid devices) have the problem that high-purity separation is difficult.

[0005] Furthermore, for VLCCs (Very Large Crude Oil Carriers) or medium-sized container ships equipped with relatively large propulsion systems, the stable operation and precise control of the pressure in the ammonia BOG (Boil-Off Gas) treatment system are critical design requirements; however, conventional technology currently has limitations in meeting the demands of such large propulsion systems.

[0006] The present invention aims to solve the aforementioned problems by providing an ammonia capture system that enables efficient ammonia separation and recycling by separating ammonia and nitrogen in stages through a redistillation process using a room-temperature separation drum and a packing column, and then recycling them in a high-purity state within the operating pressure range downstream of an ammonia re-liquefaction compressor or safely discharging them into the atmosphere.

[0007] The problem to be solved by this specification is not limited to what is described above and can be extended to various matters that can be derived from the embodiments of the invention described below.

[0008] The present invention eliminates the need to address the fundamental problems of existing systems, such as residual ammonia contaminated water and the need for additional contaminated water treatment systems, and thus can be said to perfectly align with the original purpose of capturing gaseous ammonia and the name of the system.

[0009] An ammonia capture system (100) according to one embodiment of the present invention comprises an ammonia capture drum (110) for capturing ammonia mixed vapor, an ammonia compressor and cooler (120) for compressing the ammonia mixed vapor supplied from the ammonia capture drum (110) into a high-pressure state, an ambient temperature separation drum (130) for separating the ammonia mixed vapor compressed into a high-pressure state into liquid and gas, a packing column section (140) for re-condensing the separated ammonia and nitrogen mixture to separate nitrogen and ammonia, an ammonia condenser (150) for condensing the separated ammonia vapor to convert it into liquid ammonia, a membrane filter (160) for filtering and separating nitrogen within the liquid ammonia, and a nitrogen discharge vent (170) for releasing nitrogen discharged from the membrane filter (160) into the atmosphere, wherein ammonia and nitrogen are primarily separated in the packing column section (140), and in the ammonia condenser (150) The condensed liquid ammonia can be circulated to the packing column section (140) to separate the ammonia and nitrogen.

[0010] According to one embodiment of the present invention, the ammonia compressor and cooler (120) compresses the ammonia mixed vapor to a high pressure of at least 25 bar, controls the temperature of the mixture through an after-cooler to a state suitable for redistillation and condensation processes, and can transfer the high-pressure ammonia mixture generated during the compression process to the room temperature separation drum (130).

[0011] According to one embodiment of the present invention, the room temperature separation drum (130) can maintain a portion of the ammonia mixed vapor in a gaseous state and a portion in a liquid state through temperature control under high pressure, and then supply it to the packing column section (140) after separating it into two-phase states of gas and liquid.

[0012] According to one embodiment of the present invention, the packing column section (140) may be configured to receive a mixture of ammonia and nitrogen separated into two phases through the room temperature separation drum (130), and to separate the gas and liquid of the mixture stepwise through heat exchange and surface contact through a packing material installed inside, and then to perform redistillation by moving the mixture downward or upward according to gravity and flow pressure, and to supply the redistilled ammonia to the ammonia condenser (150) and the redistilled nitrogen to the membrane filter (160), respectively.

[0013] The ammonia condenser (150) according to one embodiment of the present invention includes a shell-and-tube type heat exchanger, condenses ammonia mixed vapor into a low-temperature state to convert it into liquid ammonia, and can recover the condensed liquid ammonia to the packing column section (140) based on gravity.

[0014] According to one embodiment of the present invention, the membrane filter (160) separates nitrogen from liquid ammonia with a purity of at least 98% based on the molecular velocity principle, and the separated nitrogen can be released into the atmosphere through the nitrogen discharge vent (170).

[0015] According to one embodiment of the present invention, by separating a mixture of ammonia and nitrogen in stages through a room temperature separation drum, a low temperature ammonia condenser, and a packing column, there is an advantage of being able to efficiently recycle high-purity ammonia.

[0016] In particular, according to the present invention, by separating N2 from NH3 with a high purity of 98% or more using a membrane filter, the efficiency of the nitrogen separation process can be maximized and the atmospheric release of ammonia can be minimized, thereby having the advantage of increasing the possibility of recycling.

[0017] In addition, according to the present invention, a high purity of 99.9% or more is achieved through a pure NH3 re-liquefaction system, thereby maintaining the quality of the ammonia fuel and maximizing fuel utilization, which is an advantage.

[0018] In addition, according to the present invention, since the mixture is effectively separated in the packing column section through heat exchange and surface area contact, it has the advantage of minimizing ammonia loss and atmospheric release, which were pointed out as problems in existing systems.

[0019] In addition, according to the present invention, by combining an ammonia condenser and a membrane filter to stably release high-purity nitrogen into the atmosphere, it has the advantage of preventing environmental pollution and improving system reliability.

[0020] In addition, according to the present invention, by being designed to efficiently process ammonia BOG generated in large propulsion systems such as VLCCs and medium-sized container ships, it has the advantage of improving the operational efficiency of the fuel supply system of large vessels.

[0021] In addition, according to the present invention, it solves design and operational problems of existing ammonia fuel supply systems and has the advantage of reducing energy consumption and minimizing environmental burden.

[0022] It should be understood that the effects of this specification are not limited to the matters described above and can be extended to various contents that can be derived from the detailed description of the embodiments of the invention below.

[0023] FIG. 1 is a diagram showing the overall configuration of an ammonia capture system (100) according to one embodiment of the present invention.

[0024] FIG. 2 is a table diagram for explaining the process conditions and composition of an ammonia capture system (100) according to one embodiment of the present invention.

[0025] FIG. 3 is a diagram illustrating the results of performing a process simulation of an ammonia capture system (100) according to an embodiment of the present invention using ASPEN HYSYS.

[0026]

[0027] <Explanation of Symbols>

[0028] 100: Ammonia capture system

[0029] 110: Ammonia collection drum

[0030] 120: Ammonia Compressor and Cooler

[0031] 130: High-temperature separation drum

[0032] 140: Packing column section

[0033] 150: Ammonia condenser

[0034] 160: Membrane filter

[0035] 170: Nitrogen exhaust vent (170)

[0036] In describing the embodiments of this specification, if it is determined that a detailed description of known configurations or functions could obscure the essence of the embodiments of this specification, such detailed description is omitted. Additionally, parts of the drawings unrelated to the description of the embodiments of this specification have been omitted, and similar parts are denoted by similar reference numerals.

[0037] In the embodiments of this specification, when a component is described as being "connected," "combined," or "joined" with another component, this may include not only a direct connection but also an indirect connection in which another component exists in between. Furthermore, when a component is described as "comprising" or "having" another component, this means that, unless specifically stated otherwise, it does not exclude the other component but may include additional components.

[0038] In the embodiments of this specification, terms such as first, second, etc. are used solely for the purpose of distinguishing one component from another component and do not limit the order or importance of the components unless specifically stated otherwise. Accordingly, within the scope of the embodiments of this specification, the first component in an embodiment may be referred to as the second component in another embodiment, and likewise, the second component in an embodiment may be referred to as the first component in another embodiment.

[0039] In the embodiments of this specification, distinct components are intended to clearly explain their respective features and do not imply that the components are necessarily separated. That is, multiple components may be integrated to form a single hardware or software unit, or a single component may be distributed to form multiple hardware or software units. Therefore, such integrated or distributed embodiments are included within the scope of the embodiments of this specification, even if not otherwise mentioned.

[0040]

[0041] FIG. 1 is a diagram showing the overall configuration of an ammonia capture system (100) according to one embodiment of the present invention.

[0042] Referring to FIG. 1, an ammonia capture system (100) according to one embodiment of the present invention is largely composed of an ammonia capture drum (110), an ammonia compressor and cooler (120), a room temperature separation drum (130), a packing column section (140), an ammonia condenser (150), a membrane filter (160), and a nitrogen discharge vent (170).

[0043] The ammonia collection drum (110) efficiently collects nitrogen-containing mixed ammonia (N2-rich mixed ammonia) generated from a main engine using ammonia fuel and transfers it to a subsequent processing process.

[0044] More specifically, the ammonia collection drum (110) collects and stably stores a mixture of ammonia and nitrogen discharged from the main engine, and the ammonia collection drum (110) minimizes changes in pressure and temperature of the mixture so that the mixture is maintained in a state suitable for subsequent processing.

[0045] In addition, the ammonia collection drum (110) homogenizes the pressure and temperature of the mixed ammonia internally to maximize system efficiency before transferring it to the compressor and cooler (120), thereby preventing abrupt changes in the state of the mixture and ensuring process stability. In addition, the ammonia collection drum (110) has a sealed structure to prevent leakage of the ammonia boil-off gas (BOG), and may also protect the system by releasing excessive pressure through a safety valve when necessary in an overpressure condition.

[0046] The interior of the ammonia collection drum (110) is made of a material with excellent pressure resistance to stably accommodate the high-pressure mixture, and an internal coating or stainless steel may be applied to prevent corrosion. Additionally, if necessary, a baffle plate is installed inside the ammonia collection drum (110) to regulate the flow of the mixture, thereby optimizing the flow of the mixture and maintaining a homogeneous state.

[0047] Additionally, the inlet of the ammonia collection drum (110) may be configured to receive mixed ammonia discharged from the main engine, and the outlet may be configured to be directly connected to the compressor and cooler (120) to ensure a smooth flow of the mixture. Additionally, valves may be installed at the inlet and outlet of the ammonia collection drum (110) to control the flow of the mixture.

[0048] Additionally, the ammonia collection drum (110) may include a pressure sensor and a regulator to maintain a constant internal pressure, thereby protecting the system by releasing excess pressure through a safety valve in the event of an overpressure condition. Additionally, the ammonia collection drum (110) may further include a temperature sensor and a heat exchanger to regulate the internal temperature of the mixture, thereby supporting the mixture to be processed under optimal conditions in subsequent processes (compression and cooling).

[0049] Looking at the operating principle of the ammonia collection drum (110), the ammonia collection drum (110) may be configured to collect mixed ammonia discharged from the main engine without pressure drop, stabilize the pressure and temperature inside, and allow the mixture to circulate inside the drum without loss through a guide plate and an internal (if necessary) coating. At this time, the stabilized mixture is transferred to a compressor and cooler (120) to maintain an optimal state for subsequent processes. Here, sensors and control devices inside the drum monitor the pressure and temperature in real time and can automatically adjust them as needed. In addition, if overpressure occurs during the collection of the mixture, a safety valve operates to release the excess pressure, thereby ensuring the safety of the system. Furthermore, to prevent external leakage of the ammonia boil-off gas (BOG), the ammonia collection drum (110) is configured with a sealed structure, so that a stable sealed state can be maintained even during system operation.

[0050]

[0051] The ammonia compressor and cooler (120) processes the ammonia and nitrogen mixture delivered from the ammonia collection drum (110) at an appropriate pressure and temperature and stably supplies it to the room temperature separation drum (130).

[0052] More specifically, the ammonia compressor and cooler (120) compresses the mixture supplied from the ammonia collection drum (110) to a pressure of about 25 bar to form an appropriate pressure and temperature for transferring it to the room temperature separation drum (130). This allows for the reduction of the phase change or volume of the gas mixture during the compression process, thereby maximizing process efficiency.

[0053] In addition, the compressed mixture is lowered from a high temperature to an appropriate temperature through an ammonia compression and cooler (120), thereby allowing for optimal two-phase separation in a room temperature separation drum (130), and the temperature of the mixture is uniformly controlled during the cooling process, thereby maintaining stable process conditions.

[0054] In addition, in principle, the purpose of the ammonia capture system is to effectively re-liquefy the ammonia into a gaseous state through compression cooling and return it to the ammonia storage system for storage. Therefore, the pressure and temperature of the compression-cooled ammonia are controlled so that the ammonia at room temperature becomes a two-phase state. At this time, depending on the operating pressure of the compressor and cooler and the ammonia flow rate, the liquid and gas coexist in a saturated state in the adiabatic system, requiring a separation drum at room temperature. Since the mixed nitrogen has a physical characteristic of not dissolving into the highly polar liquid ammonia, it coexists in a gaseous state as a mixed gas with the saturated ammonia.

[0055] Additionally, the compressor and cooler (120) effectively cools the temperature raised by compression during the cooling process, thereby lowering the total amount of internal energy of the mixture, and some or a large amount of ammonia changes into a liquid state inside the cooler. The compressor and cooler (120) may optionally use a standard Shell & Tube type heat exchanger or a plate type heat exchanger. Due to the characteristics of nitrogen, its physical and chemical properties are different from those of ammonia, so chemical changes or losses of the mixture do not occur unless it is in a plasma state.

[0056] In one embodiment, this ammonia compressor and cooler (120) may include a compressor, a cooler, an inlet / outlet connection, and a safety device.

[0057] The compressor enables efficient achievement of high pressure by compressing the mixture stepwise or simply through a multi-stage or single-stage compression system, and can be constructed with a structure having excellent pressure resistance and an internal sealed design to prevent leakage during the compression process of the mixture. Additionally, in one embodiment, a rotary compressor (e.g., a screw compressor) is applied to the compressor, thereby enabling the processing of ammonia and nitrogen mixtures at high pressure.

[0058] The cooler can efficiently remove heat from the mixture through an internal heat exchanger to cool it to room temperature, and can use ordinary cooling water. It can also maintain an optimal temperature according to process conditions by detecting and controlling the temperature of the mixture in real time during the cooling process through a temperature control sensor. Additionally, the inlet of the inlet / outlet connection receives the mixture from an ammonia collection drum (110) or an ammonia storage tank, and can control the flow of the mixture by adjusting the operating load of the compressor.

[0059] In addition, the safety device can detect an overpressure condition inside the compressor through a pressure sensor and a safety valve, and maintain the safety of the system by releasing the excessive pressure when necessary, and can prevent the temperature of the cooler from rising through a cooler overheating prevention device.

[0060] Looking at the operating principle of the ammonia compressor and cooler (120), first, a mixture delivered from the ammonia collection drum (110) flows into the inlet of the compressor in the ammonia compressor and cooler (120), undergoes a multi-stage compression process, and is processed into a high-pressure state. During the compression process, the volume of the mixture decreases and the phase changes, and in the gaseous state region, the ammonia and nitrogen are maintained homogeneously.

[0061] Next, the compressed mixture is moved to a cooler and lowered to an appropriate temperature through a heat exchange process, and the cooler adjusts the temperature of the mixture to a level suitable for a subsequent process, thereby increasing the separation efficiency in the room temperature separation drum (130).

[0062] Next, the compressed and cooled mixture is transferred to a room temperature separation drum (130), during which the pressure and temperature are maintained stably, and the pressure and temperature may be monitored in real time through internal sensors and control devices.

[0063]

[0064] The room temperature separation drum (130) processes a mixture of ammonia and nitrogen delivered from the ammonia compressor and cooler (120) and serves to separate the ammonia and nitrogen into gas and liquid in a two-phase state. This room temperature separation drum (130) stably separates the mixture based on the physical properties of the gas and liquid and has a configuration that maximizes the efficiency of subsequent processes.

[0065] More specifically, the room temperature separation drum (130) receives the mixed ammonia compressed and cooled in the ammonia compression and cooling unit (120) and separates it into gaseous and liquid states in stages inside. In this process, the ammonia is mainly accumulated in a liquid state at the bottom, and the ammonia mixed with nitrogen is collected in a saturated gaseous state at the top.

[0066] In addition, for stable separation of the mixture, a baffle plate and a guide plate may be installed inside the room temperature separation drum (130), thereby optimizing the flow of the mixture.

[0067] Additionally, in the process of separating the gas and liquid of the mixture compressed by the ammonia compressor (120), the ambient temperature separation drum (130) reduces the pressure of the liquid ammonia through a pressure reducing valve connected to the ambient temperature separation drum (130) to lower the pressure, and during the pressure reduction process, the ammonia is cooled to a low temperature and supplied to the ammonia condenser (150) through a separate supply line and can be used as a cooling medium for the ammonia condenser (150).

[0068] Looking at the operating principle of the room temperature separation drum (130), a mixture supplied in a high-pressure state from the ammonia compressor and cooler (120) flows into the room temperature separation drum (130) and passes through the internal heat exchanger to maintain a stable state. Subsequently, the mixture is separated into gas and liquid, and the separated pure ammonia liquid moves to the bottom, while the ammonia nitrogen mixed gas moves to the top and is delivered to the packing column section (140) and the membrane filter (160), respectively.

[0069]

[0070] The ammonia condenser (150) processes the ammonia vapor delivered from the packing column section (140) and condenses it into high-purity liquid ammonia. Through this, the ammonia condenser (150) efficiently condenses the ammonia vapor through a heat exchange process and can maximize the recyclability of the ammonia fuel through a circulation process.

[0071] More specifically, the ammonia condenser (150) converts the ammonia vapor delivered from the packing column section (140) into a liquid state using a shell-and-tube type heat exchanger. At this time, the depressurized low-temperature ammonia flows through the tubes of the condenser, and in the shell section, the cooling medium absorbs heat to lower the temperature of the ammonia and selectively condenses only the ammonia. In this process, the ammonia maintains high purity (99.9% or more) and is converted into a liquid state that can be used in a subsequent fuel supply process.

[0072] Additionally, the ammonia condenser (150) can be formed of a highly conductive material to maximize internal heat exchange efficiency and has a structure that maximizes the contact area between the cooling medium and the ammonia. Through this, the ammonia vapor can be effectively condensed while minimizing heat loss.

[0073] Additionally, the inlet and outlet connection of the ammonia condenser (150) serves to receive ammonia vapor and discharge condensed liquid ammonia, and the inlet of the ammonia condenser (150) is connected to the packing column (140) to receive ammonia vapor, and the outlet circulates the condensed liquid ammonia to the ammonia recycling process.

[0074] In addition, the ammonia condenser (150) basically allows only ammonia condensed by gravity to flow downward, so no separate means for controlling the flow rate is required.

[0075] Looking at the operating principle of the ammonia condenser (150), the ammonia condenser (150) receives ambient temperature nitrogen-mixed ammonia vapor delivered from the packing column section (140), removes heat through a cooling medium, and proceeds with the condensation process. Here, the pressure of the liquid ammonia is reduced through a pressure reducing valve connected to the ambient temperature separation drum (130), and during the pressure reduction process, the ammonia is cooled to a low temperature and can be used as a refrigerant medium for the ammonia condenser (150). Additionally, the ammonia gradually converts into a liquid state, and the condensed liquid ammonia is collected at the bottom of the system through gravity and an internal induction path. Subsequently, the liquid ammonia is delivered to the ammonia fuel supply system for the recycling process. At this time, the pressure and temperature inside the condenser are monitored in real time, and when an overpressure condition occurs, a safety valve operates to maintain the stability of the system.

[0076] Additionally, the high-purity liquid ammonia from the ammonia condenser (150) can be finally supplied to and stored in an ammonia collection drum (110) or a storage tank, which means a line for recovering pure ammonia with unnecessary nitrogen removed back into the ammonia collection drum (110).

[0077] Additionally, in the ammonia condenser (150), some of the mixed gas coming out of the ammonia condenser (150) can be sent back to the packing column section (140) to allow for an additional redistillation process to be carried out for components that are not completely purified (such as residual nitrogen). Through this, the ammonia condenser (150) can allow for additional purification of gaseous ammonia containing some impurities through a redistillation process.

[0078]

[0079] The membrane filter (160) processes a mixture containing nitrogen delivered from the packing column section (140) or the room temperature separation drum (130) to separate high-purity nitrogen and safely release it into the atmosphere. This membrane filter (160) can selectively separate ammonia and nitrogen through a high-efficiency separation process, and can serve to minimize fuel loss and ensure environmental stability.

[0080] More specifically, the membrane filter (160) may be a selectively permeable membrane designed based on the difference in physical properties between nitrogen and ammonia. At this time, as the mixture passes through the permeable layer of the membrane, nitrogen is selectively permeated and released into the atmosphere through the exhaust vent (170), while ammonia remains in the non-permeable layer and can be circulated to a recycling process. In this process, the membrane filter (160) can separate nitrogen with a high purity of 98% or more, and the risk of environmental pollution can be effectively reduced by increasing the purity of the nitrogen released into the atmosphere.

[0081] The structure of the membrane filter (160) consists of a porous permeable layer and a non-permeable layer, and may include a sensor and a valve for controlling internal pressure and temperature. Additionally, the inlet of the membrane filter (160) may be connected to a packing column section (140) or an ambient temperature separation drum (130) to receive a mixture, and the outlet may transfer the separated nitrogen and ammonia to a discharge vent (170) and an ammonia condenser (150), respectively.

[0082] Looking at the operating principle of such a membrane filter (160), the membrane filter (160) introduces a mixture and then controls the pressure and flow rate to maintain appropriate conditions while carrying out the separation process. At this time, nitrogen passes through the permeable layer through the selective permeability of the membrane, while ammonia remains in the non-permeable layer and is circulated to the recycling process. In this process, the high selectivity and efficient design of the membrane filter (160) maximize separation performance, and the separated components can be safely processed through their respective paths.

[0083]

[0084] The nitrogen exhaust vent (170) serves to safely release high-purity nitrogen separated from the membrane filter (160) into the atmosphere. Through this, the nitrogen exhaust vent (170) can efficiently control the nitrogen exhaust process to minimize the impact of the nitrogen released into the atmosphere on the environment.

[0085] This nitrogen exhaust vent (170) is directly connected to the membrane filter (160) to regulate pressure and flow rate before the separated nitrogen is discharged. The nitrogen exhaust vent (170) contains a flow rate control valve and a pressure sensor, allowing nitrogen to be discharged into the atmosphere at a constant flow rate and pressure. Through this structure, the nitrogen exhaust vent (170) supports the stable operation of the membrane filter (160) and ensures both safety and efficiency during the discharge process into the atmosphere.

[0086] In addition, the nitrogen exhaust vent (170) is made of a material with excellent corrosion resistance and durability, so that it can maintain long-term stability even in an environment where high-purity nitrogen is emitted. Furthermore, a leak prevention mechanism is applied inside the nitrogen exhaust vent (170) to prevent ammonia residue from leaking into the atmosphere, thereby reducing fuel loss and preventing environmental pollution.

[0087] This nitrogen exhaust vent (170) receives nitrogen delivered from the membrane filter (160), regulates the pressure and flow rate before exhaust, and the pressure sensor monitors the pressure inside the vent in real time, and automatically operates the control valve in the event of overpressure to ensure safe exhaust. Through this, the nitrogen exhaust vent (170) has the advantage of optimizing the nitrogen exhaust process and maintaining the purity of the nitrogen released into the atmosphere.

[0088]

[0089] FIG. 2 is a table diagram for explaining the process conditions and composition of an ammonia capture system (100) according to one embodiment of the present invention.

[0090] Looking at FIG. 2, the re-liquefaction process of the ammonia capture system (100) according to the present invention is fixed for high-efficiency separation and recycling, and in particular, the operating conditions and composition of the room temperature separation drum (130) can play a key role in maximizing the purity of the re-liquefied ammonia.

[0091] For example, 200 kg / h of ammonia is processed in the re-liquefaction process, so that it can operate stably even in the fuel supply system of a large ship, and the re-liquefied ammonia maintains a high purity of 99.8% or more at the bottom of the room temperature separation drum (130).

[0092]

[0093] FIG. 3 is a diagram illustrating the results of performing a process simulation of an ammonia capture system (100) according to an embodiment of the present invention using ASPEN HYSYS.

[0094] Looking at FIG. 3, first, a mixture of ammonia and nitrogen is introduced from an ammonia collection drum (110). In the ammonia collection drum (110), the gas and liquid are separated in the first stage, and the liquid ammonia is stored at the bottom while the mixture of gaseous ammonia and nitrogen moves to the top. Subsequently, the gaseous mixture of ammonia is compressed and cooled through an ammonia compressor and cooler (120), and the pressure and temperature are controlled to prepare the ammonia for condensation.

[0095] The ammonia mixture thus controlled is transferred to a room temperature separation drum (130), where some gaseous components are removed at high temperatures and ammonia and nitrogen are further separated. It then moves to a packing column section (140) where a redistillation process takes place, where additional separation is carried out using the difference in specific gravity between nitrogen and ammonia. Additionally, nitrogen moves to the top, and the purified liquid ammonia moves to the bottom.

[0096] Afterward, the nitrogen separated in the packing column section (140) and some residual gaseous ammonia are transferred to the ammonia condenser (150). In the ammonia condenser (150), the remaining ammonia is liquefied and recovered as much as possible, and the nitrogen remaining in a gaseous state is finally transferred to the membrane filter (160). In the membrane filter (160), the nitrogen and ammonia are finally separated to increase the purity of the nitrogen.

[0097] Finally, the separated high-purity nitrogen is safely discharged to the outside through the nitrogen exhaust vent (170), and the purified liquid ammonia is recovered and stored. Through this process, the ammonia is purified to a high purity for final storage and utilization, and the nitrogen is separated and removed from the system.

[0098]

[0099] Although the present invention has been described in relation to some embodiments, various modifications and changes may be made without departing from the scope of the invention as understood by a person skilled in the art to which the invention pertains. Furthermore, such modifications and changes should be considered to fall within the scope of the claims appended to this specification.

[0100] The present invention is an ammonia capture system that enables efficient ammonia separation and recycling when applied to a ship's ammonia (NH3) fuel supply system, and is a technology that can realize its practical and economic value through widespread use in the shipbuilding and marine industry.

Claims

1. Ammonia collection drum (110) for collecting ammonia mixed vapor; an ammonia compressor and cooler (120) that compresses the ammonia mixed vapor supplied from the ammonia collection drum (110) into a high-pressure state; A room temperature separation drum (130) for separating liquid and gas from ammonia mixed vapor compressed under high pressure; A packing column section (140) for separating nitrogen and ammonia by redistilling the separated mixture of ammonia and nitrogen; an ammonia condenser (150) that condenses separated ammonia vapor to convert it into liquid ammonia; A membrane filter (160) for filtering and separating nitrogen in the above liquid ammonia; and It includes a nitrogen exhaust vent (170) that releases nitrogen discharged from the above membrane filter (160) into the atmosphere; Ammonia and nitrogen are separated primarily in the packing column section (140), and the liquid ammonia condensed in the ammonia condenser (150) is circulated to the packing column section (140) to separate the ammonia and nitrogen respectively. Ammonia capture system.

2. In Paragraph 1, The above ammonia compressor and cooler (120) is, Compressing the ammonia mixed vapor to a high pressure of at least 25 bar, adjusting the temperature of the mixture through an after-cooler to a state suitable for redistillation and condensation processes, and transferring the high-pressure ammonia mixture generated during the compression process to the room temperature separation drum (130). Ammonia capture system.

3. In Paragraph 1, The above room temperature separation drum (130) is, Ammonia mixed vapor is maintained in a gaseous state and a liquid state through temperature control under high pressure, so that some of it is separated into two-phase states of gas and liquid and then supplied to the packing column section (140). Ammonia capture system.

4. In Paragraph 1, The above packing column section (140) is, A mixture of ammonia and nitrogen separated into two phases through the above-mentioned room temperature separation drum (130) is received, and the gas and liquid of the mixture are separated stepwise through heat exchange and surface contact via a packing material installed inside, and then redistillation is performed by moving the mixture downward or upward according to gravity and flow pressure, and the redistilled ammonia is supplied to the above-mentioned ammonia condenser (150) and the redistilled nitrogen is supplied to the above-mentioned membrane filter (160), respectively. Ammonia capture system.

5. In Paragraph 1, The above ammonia condenser (150) is, It includes a shell-and-tube type heat exchanger, condenses ammonia mixed vapor to a low temperature state to convert it into liquid ammonia, and recovers the condensed liquid ammonia to the packing column section (140) based on gravity. Ammonia capture system.

6. In Paragraph 1, The above membrane filter (160) is, Based on the molecular velocity principle, nitrogen is separated from liquid ammonia with a purity of at least 98% or more, and the separated nitrogen is released into the atmosphere through the nitrogen discharge vent (170). Ammonia capture system.

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