Ammonia recovery and SCR device reutilization system based on marine ammonia fuel supply system and ship

Abstract

The invention discloses an ammonia recovery and SCR device reutilization system based on a marine ammonia fuel supply system. The ammonia recovery and SCR device reutilization system comprises an ammonia water recovery and storage system, an ammonia water mixing unit module, an ammonia water injection control module and a smoke exhaust pipe, the system further comprises a PLC control module. The ammonia water mixing unit module comprises an ammonia water mixing and conveying pump set, a first valve, an ammonia water mixing tank and a water conveying module; the ammonia water mixing and conveying pump set is connected with the ammonia water collecting and storing tank and is connected with the ammonia water mixing tank through a first valve; the water conveying module is connected with the ammonia water mixing tank through a pipeline, and a second valve is arranged between the water conveying module and the ammonia water mixing tank; the PLC control module controls the concentration of the mixed ammonia water to be smaller than 25% by remotely controlling the opening degrees of the first valve and the second valve, and the ammonia water is sprayed to a smoke exhaust pipe through the ammonia water spraying control module. The proportion of ammonia water and clear water can be adjusted in real time according to flue gas analysis data, and economic rationalization of the using amount of the reducing agent is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of ammonia fuel supply systems for ships, and in particular to an ammonia recovery and SCR device reuse system based on a marine ammonia fuel supply system and a ship. Background Art

[0002] With the rapid development of the global shipping industry, the environmental impact of ship emissions is gaining increasing attention. Ammonia fuel, as a clean and efficient energy alternative, is becoming a research hotspot in the shipping industry. However, ship ammonia fuel supply systems face numerous challenges in practical operation, particularly regarding ammonia emissions.

[0003] Traditional marine ammonia fuel supply systems often rely on end-of-pipe treatment technologies, such as direct discharge or simple control, without effective recovery and reuse of ammonia resources. This approach not only wastes ammonia resources but also poses a potential threat to the environment. For example, ammonia emissions from ammonia purges and equipment accessory leaks not only increase operating costs but can also contribute to air pollution and water eutrophication.

[0004] Existing SCR (Selective Catalytic Reduction) systems typically require the additional purchase of denitrification agents (such as urea or liquid ammonia), which not only increases ship operating costs but also poses safety risks during transportation and storage. Furthermore, high-concentration ammonia solutions tend to crystallize at low temperatures, potentially clogging pipelines and equipment, further increasing maintenance complexity and costs.

[0005] To address these issues, some technologies attempt to recover ammonia emissions, but they generally have the following shortcomings:

[0006] Low recovery efficiency: Traditional recovery technologies are unable to efficiently collect ammonia emissions, resulting in waste of resources.

[0007] Inaccurate concentration control: Lack of precise control of ammonia concentration affects the denitrification efficiency of the SCR device.

[0008] Insufficient automation: Reliance on manual operation, slow response, and prone to errors.

[0009] Insufficient safety: Lack of multiple safety protection mechanisms, resulting in risks of leakage and explosion. Summary of the Invention

[0010] The present invention aims to overcome at least one of the above-mentioned defects of the prior art and provide an ammonia recovery and SCR device reuse system and a ship based on a marine ammonia fuel supply system, so as to realize the recycling and reuse of ammonia water resources, significantly reduce the operating costs of ships, and at the same time reduce the dependence of ammonia dual-fuel ships on external denitrification agents, thereby fundamentally reducing ammonia emissions and the overall environmental burden.

[0011] The present invention provides an ammonia recovery and SCR device reuse system based on a marine ammonia fuel supply system, comprising an ammonia water recovery and storage system, an ammonia water mixing unit module, an ammonia water injection control module, and a smoke exhaust pipe; and also includes a PLC control module. The ammonia water mixing unit module includes an ammonia water mixing and delivery pump assembly, a first valve, an ammonia water mixing tank, and a water delivery module. The ammonia water mixing and delivery pump assembly is connected to the ammonia water collection and storage tank and to the ammonia water mixing tank via a first valve. The water delivery module is connected to the ammonia water mixing tank via a pipeline, with a second valve disposed between the water delivery module and the ammonia water mixing tank. The PLC control module controls the opening of the first and second valves to control the concentration of the mixed ammonia water to less than 25%, and sprays the mixed ammonia water into the smoke exhaust pipe via the ammonia water injection control module. The use of the PLC control module makes the entire ammonia recovery and SCR device reuse process more convenient, responsive, and stable. Through precise automated control, the system can adjust the ratio of ammonia water to clean water according to real-time flue gas analysis data, achieve economic rationalization of reducing agent usage, and thus improve the overall operational efficiency of the system. The reducing agent concentration and injection volume at the nozzle need to be automatically adjusted, and the flow ratio of ammonia water to clean water is optimized according to real-time flue gas analysis data to achieve economic rationalization of reducing agent usage.

[0012] The present invention achieves maximum utilization of ammonia resources by precisely controlling the ammonia concentration to the high-efficiency range of 22-25%, the optimal denitrification efficiency range, and directly supplies it to the exhaust gas denitrification device, thereby reducing dependence on external denitrification agents and significantly reducing the operating costs of ships. Compared with traditional systems, it saves approximately 40% of ammonia consumption.

[0013] Furthermore, the ammonia water injection control module includes an ammonia water pressure pump group, a first flow meter and a nozzle connected by a pipeline; the nozzle is connected to the smoke exhaust pipe.

[0014] As a preferred embodiment, the flow rate of the ammonia water pressurized water pump group is variable frequency stepless regulation. Based on the variable frequency regulation, the dynamic response time of the control valve regulation can be less than 30 seconds.

[0015] Furthermore, the ammonia mixing unit module also includes the second flowmeter, ammonia concentration detector, a first low liquid level sensor and a first high liquid level sensor electrically connected to the PLC control module; the ammonia collection and storage tank is provided with a second low liquid level sensor and a second high liquid level sensor electrically connected to the PLC control module.

[0016] The system is equipped with multiple alarm mechanisms, including those for liquid level, flow rate, frequency conversion failure, and pressure, ensuring safe and stable operation. The ammonia-water mixing unit utilizes a water pump and metering devices, such as an electric valve, flow meter, and concentration detector. In the mixing tank, 30% ammonia and clean water are precisely diluted to achieve the ideal concentration for optimal denitrification efficiency, within the 22-25% range required for injection.

[0017] Furthermore, the water delivery module includes a clean water storage tank and a clean water flushing pump group connected in sequence through pipelines; the clean water flushing pump group is connected to the ammonia mixing tank through a branch pipe; and is connected to the suction port of the clean water mixing delivery pump group through another branch pipe.

[0018] Furthermore, the present invention also includes a flushing module, which includes a clean water flushing pump group, a first flushing pipeline and a second flushing pipeline; one end of the first flushing pipeline is connected to the clean water flushing pump group, and the other end is connected to the nozzle; one end of the second flushing pipeline is connected to the clean water flushing pump group, and the other end is connected to the front of the ammonia mixing and delivery pump group; the clean water flushing pump group is electrically connected to the PLC control module. In addition, the design of the flushing module enables the automatic cleaning of residual ammonia in the pipeline during system maintenance or shutdown, effectively preventing environmental and personnel safety risks. Regular flushing maintenance reduces the residual and crystallization of ammonia in the pipelines and equipment, avoiding corrosion and blockage problems caused by long-term accumulation, thereby extending the service life of related equipment and reducing long-term maintenance costs.

[0019] Preferably, the ammonia recovery and storage system includes an ammonia emission collection tank, an ammonia discharge collection tank, an ammonia collection and delivery pump group, and an ammonia collection and storage tank connected by pipelines; the ammonia emission collection tank and the ammonia discharge collection tank are connected in parallel and then connected in series with the ammonia collection and delivery pump group and the ammonia collection and storage tank.

[0020] Ammonia is collected by the ammonia fuel supply system's ammonia emission collection system. The ammonia recovery and storage system securely stores the collected ammonia. Core components include an ammonia collection and delivery pump assembly, several valve and piping accessories, and a large stainless steel ammonia pressure tank. Its capacity has been carefully calculated to provide a stable supply for 10-20 days, reducing the frequency of catalytic reductant replenishment for the SCR unit. A pressure protection switch and a breather valve are installed on the top of the tank, along with a high-precision level gauge and pressure transmitter for real-time monitoring and adjustment. When a typical marine ammonia fuel emission collection system uses fresh water to absorb ammonia, the maximum theoretical ammonia concentration is approximately 30%. Given the low crystallization temperature of 30% ammonia, the tank itself requires no additional freeze protection and can be installed in a sheltered area. The ammonia delivery pipeline is fully insulated to withstand ambient temperature fluctuations. Given the ammonia reductant concentration requirements of the marine SCR unit, the ammonia and fresh water must be appropriately diluted in the ammonia mixing tank to ensure efficient denitrification. It is then pressurized by a pressure water pump and accurately transported to the spray gun on the SCR device through a pipeline.

[0021] Preferably, the exhaust pipe is equipped with a flue gas analyzer, which is electrically connected to the PLC control module. The amount of reducing agent injected at the nozzle is also optimized based on real-time flue gas analysis data to control the flow of the pressurized water pump. The flow of the pressurized water pump is regulated using variable frequency drive to ensure precise and efficient flow regulation. The system supports both automatic and manual control on-site, as well as remote central control, enabling automatic control of the injection flow rate based on demand.

[0022] Preferably, the first valve and the second valve are both three-way valves.

[0023] The present invention also provides an energy-saving ship, comprising a hull, and an ammonia recovery and SCR device reuse system based on a marine ammonia fuel supply system arranged on the hull.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention aims to propose an ammonia recovery and reuse process that is efficient, reliable and environmentally friendly in the technical field of ship ammonia fuel supply systems. This process not only deeply optimizes the operational efficiency of ship ammonia fuel systems, but also significantly promotes the green and sustainable development of the shipping industry. Specifically, this process innovatively introduces a precise control technology for the concentration of recovered ammonia water, stably adjusting the concentration of treated ammonia water to no more than 25%. This concentration optimization strategy directly improves the efficiency of subsequent applications. Subsequently, this process designs a dedicated supply system to accurately deliver this ammonia water of appropriate concentration to the ship's exhaust gas denitrification device for use as a key catalytic reducing agent. This step not only realizes the recycling of ammonia water and significantly reduces the operating costs of the ship, but more importantly, the high purity of marine ammonia fuel can be directly used as a catalytic reducing agent for the ship's SCR denitrification device. It effectively replaces the traditional denitrification agent that may need to be purchased separately, thereby fundamentally reducing the external dependence and overall emissions of ammonia, and significantly reducing the negative impact of ship activities on the environment.

[0026] The application of this invention provides the shipping industry with a new, highly efficient ammonia fuel supply system solution, promoting innovation and development in environmental technologies within the shipping industry and contributing to a more environmentally friendly and sustainable industrial ecosystem. Vessels employing this solution will offer significant advantages in both operating costs and environmental performance, enabling them to meet increasingly stringent environmental regulations and enhance their competitiveness in the international shipping market. The system also features a redundant design, ensuring operational operation in the event of single-point failures or maintenance. The system also boasts a simple design, low cost, easy operation and maintenance, and requires minimal installation space. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the ammonia recovery and SCR device reuse system of the present invention. DETAILED DESCRIPTION

[0028] The drawings in the embodiments provide a more detailed description of the technical solutions in the embodiments of the present invention. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of the present invention, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present invention, and should not be understood as limiting the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The embodiments of the present invention are described in detail below with reference to the drawings.

[0029] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0030] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application. Example

[0031] The embodiment of the present invention provides an ammonia recovery and SCR device recycling system based on a marine ammonia fuel supply system, such as Figure 1 As shown, the system includes an ammonia recovery and storage system, which safely stores collected ammonia. Its core components include an ammonia collection and delivery pump assembly 3, several valve and piping accessories, and a large, stainless steel, pressure-operated ammonia collection and storage tank 4. Its capacity has been carefully calculated to provide a stable supply for 10-20 days, reducing the frequency of catalytic reductant replenishment for the SCR unit. A pressure protection switch and a breather valve are installed on the top of the tank, along with a high-precision level gauge and pressure transmitter for real-time status monitoring and adjustment. Ammonia is primarily collected from the ammonia fuel supply system's nitrogen-purged ammonia emission collection tank 1 and ammonia bleed collection tank 2. Branch lines 101 and 102 converge with a main pipe 103, powering the ammonia collection and delivery pump assembly 3. Pipeline 104 downstream of the pump delivers the ammonia to the ammonia collection and storage tank 4. A second low liquid level sensor 6 and a second high liquid level sensor 5 are arranged on the ammonia collection and storage tank 4. The sensor signals are collected by the PLC control module 20, and the converted signals automatically control the start and stop of the ammonia collection and delivery pump group 3, thereby realizing automatic control of the ammonia recovery and storage system.

[0032] PLC centralized automatic control system: The entire system is equipped with an advanced PLC centralized automatic control system, with the PLC control module 20 as a key component, ensuring convenient operation, rapid response, and stable operation. Flexible and diverse control methods meet the needs of different operating conditions. The system also incorporates multiple alarm mechanisms, including liquid level, flow rate, frequency conversion fault, and pressure alarms, to comprehensively ensure safe and stable system operation.

[0033] The reducing agent concentration and injection volume at the nozzle need to be automatically adjusted, and the flow ratio of ammonia water and clean water should be optimized based on real-time flue gas analysis data to achieve economic rationality in the use of reducing agent.

[0034] Ammonia mixing unit: The ammonia mixing unit utilizes a water pump and metering devices, such as an electric valve, flow meter, and concentration detector. In the ammonia mixing tank 9, 30% ammonia and clean water are precisely diluted to achieve the ideal 22-25% concentration required for injection. Ammonia water with a concentration of 30% is output from the ammonia water collection and storage tank 4, and reaches the ammonia water mixing and delivery pump group 7 through the pipeline 113. There is a remote-controlled first valve behind the pump, a branch pipe 106 is connected to the ammonia water mixing tank 9, and a branch pipe 105 is connected to the suction port of the ammonia water mixing and delivery pump group 7. A second flow meter is installed on the 106 pipeline; at the same time, the clean water in the clean water storage tank 13 is transported to the clean water mixing and delivery pump group 14 through the pipeline 110. There is a remote-controlled second valve behind the clean water mixing and delivery pump group 14, a branch pipe 107 is connected to the ammonia water mixing tank 9, and a branch pipe 109 is connected to the suction port of the clean water mixing and delivery pump group 14. A third flow meter 23 is installed on the 109 pipeline; the PLC control module 20 collects the flue gas temperature, concentration and other information fed back from the flue gas analyzer 18 on the exhaust pipe 19, processes and converts it into the corresponding concentration requirements for ammonia water, and collects the flue gas from the ammonia water mixing tank. The ammonia concentration detector 12 on 9 obtains the current ammonia concentration, and the PLC control module 20 automatically adjusts the concentration based on the ammonia concentration ratio analysis, adjusts the opening of the remote-controlled first valve and the second valve 15, and controls the flow of the management branches 105 and 109, thereby controlling the flow of ammonia and clean water input into pipelines 106 and 107. At the same time, the second flow meter and the third flow meter 23 detect and feedback the real-time flow to form an information closed-loop control, and accurately adjust the mixed flow of ammonia in pipeline 106 and clean water in pipeline 107, so that the ammonia concentration of the ammonia mixing tank 9 meets the technical requirements; at the same time, the ammonia mixing tank 9 is equipped with a first low liquid level sensor 11 and a first high liquid level sensor 10 to monitor the liquid level in real time, and control the automatic start and stop of the clean water mixing and delivery pump group 14 and the ammonia mixing and delivery pump group 7; realizing automatic control of the ammonia mixing unit module.

[0035] Ammonia injection control module: Ammonia that meets the concentration requirements is transported to the ammonia booster pump group 16 by pipeline 111. The outlet of the ammonia booster pump group 16 and the nozzle 22 are connected by pipeline 112. A first flow meter 17 is installed on the pipeline 112. The amount of reducing agent injection at the nozzle 22 is also optimized according to the real-time flue gas analyzer 18 data to optimize the flow of the ammonia booster pump group 16. The flow of the ammonia booster pump group 16 is adjusted by variable frequency stepless adjustment to ensure accurate and efficient flow regulation. At the same time, the flow is detected in real time by the first flow meter 17, and the flow data is fed back to the ammonia booster pump group 16 to form an information closed-loop control to accurately control the injection flow. The system can automatically / manually control the function on site, and can also be remotely controlled to achieve automatic control of the injection flow according to demand.

[0036] Flushing Module: The system is equipped with a flushing module, designed to automatically activate during system maintenance or downtime to thoroughly clean residual ammonia from the pipelines, effectively preventing environmental and personnel safety risks while extending equipment life. Wash water is transported from clean water storage tank 13 via pipeline 121 to clean water flushing pump unit 21. Pipeline 122 then branches into branches 123 and 124. Pipeline 123 connects near ammonia injection nozzle 22 to flush residual ammonia back to the ammonia washing mixing tank 9. Another pipeline, 124, connects before the ammonia mixing pump unit 7 to flush residual ammonia back to the ammonia washing mixing tank 9. The clean water flushing pump unit 21 can be started and stopped remotely.

[0037] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the above preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent replacements of the technical solutions of the present invention may be made without departing from the spirit and scope of the technical solutions of the present invention. Those skilled in the art may also make other changes within the spirit of the present invention and apply them to the design of the present invention, as long as they do not deviate from the technical effects of the present invention. These changes made in accordance with the spirit of the present invention should all be included in the scope of protection claimed by the present invention.

Claims

1. An ammonia recovery and SCR device reuse system based on a marine ammonia fuel supply system, characterized in that: It includes an ammonia water recovery and storage system, an ammonia water mixing unit module, an ammonia water injection control module and a smoke exhaust pipe (19); and also includes a PLC control module; The ammonia mixing unit module comprises an ammonia mixing and delivery pump group (7), a first valve (8), an ammonia mixing tank (9), and a water delivery module; the ammonia mixing and delivery pump group (7) is connected to the ammonia collection and storage tank (4), and is connected to the ammonia mixing tank (9) through the first valve (8); the water delivery module is connected to the ammonia mixing tank (9) through a pipeline, and a second valve (15) is provided between the water delivery module and the ammonia mixing tank (9); The PLC control module controls the opening of the first valve (8) and the second valve (15) by remote control to control the concentration of the mixed ammonia water to be less than 25%, and sprays the ammonia water to the exhaust pipe (19) through the ammonia water injection control module.

2. The ammonia recovery and SCR device reuse system based on the marine ammonia fuel supply system according to claim 1 is characterized in that: The ammonia water injection control module comprises an ammonia water pressure pump group (16), a first flow meter (17) and a nozzle (22) connected through a pipeline; the nozzle (22) is connected to the smoke exhaust pipe (19).

3. The ammonia recovery and SCR device reuse system based on the marine ammonia fuel supply system according to claim 2 is characterized in that: The flow rate of the ammonia water pressure pump group is variable frequency stepless adjustment.

4. The ammonia recovery and SCR device reuse system based on the marine ammonia fuel supply system according to claim 1 is characterized in that: The ammonia water mixing unit module further comprises a second flow meter (24) electrically connected to the PLC control module, an ammonia water concentration detector (12), a first low liquid level sensor (11) and a first high liquid level sensor (10); the ammonia water collecting and storing tank (4) is provided with a second low liquid level sensor (6) and a second high liquid level sensor (5) electrically connected to the PLC control module.

5. The ammonia recovery and SCR device reuse system based on the marine ammonia fuel supply system according to claim 1 is characterized in that: The water delivery module comprises a clean water storage tank (13) and a clean water flushing pump group (21) connected in sequence through pipelines; the clean water flushing pump group (21) is connected to the ammonia mixing tank (9) through a branch pipe; and is connected to the suction port of the clean water mixing delivery pump group (14) through another branch pipe.

6. The ammonia recovery and SCR device reuse system based on the marine ammonia fuel supply system according to claim 5 is characterized in that: The invention also includes a flushing module, which includes a clean water flushing pump group (21), a first flushing pipeline, and a second flushing pipeline; one end of the first flushing pipeline is connected to the clean water flushing pump group (21), and the other end is connected to the nozzle (22); one end of the second flushing pipeline is connected to the clean water flushing pump group (21), and the other end is connected to the front of the ammonia mixing and delivery pump group (7); the clean water flushing pump group (21) is electrically connected to the PLC control module.

7. The ammonia recovery and SCR device reuse system based on the marine ammonia fuel supply system according to claim 1 is characterized in that: The ammonia water recovery and storage system comprises an ammonia gas emission collection tank (1), an ammonia discharge collection tank (2), an ammonia water collection and delivery pump group (3), and an ammonia water collection and storage tank (4) connected by pipelines; the ammonia gas emission collection tank (1) and the ammonia discharge collection tank (2) are connected in parallel and then connected in series with the ammonia water collection and delivery pump group (3) and the ammonia water collection and storage tank (4).

8. The ammonia recovery and SCR device reuse system based on the marine ammonia fuel supply system according to claim 1 is characterized in that: The smoke exhaust pipe (19) is provided with a flue gas analyzer (18), and the flue gas analyzer (18) is electrically connected to the PLC control module.

9. The ammonia recovery and SCR device reuse system based on the marine ammonia fuel supply system according to claim 1, characterized in that: The first valve (8) and the second valve (15) are both three-way valves.

10. An energy-saving ship, characterized in that: The invention comprises a hull and an ammonia recovery and SCR device reuse system based on a marine ammonia fuel supply system as claimed in any one of claims 1 to 9.

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