Multi-tower alternating type zeolite carbon dioxide capturing system suitable for LNG transport ship

Abstract

The invention provides a multi-tower alternate zeolite carbon dioxide trapping system suitable for an LNG transport ship, which comprises a multi-tower zeolite adsorption-desorption unit, the multi-tower zeolite adsorption-desorption unit comprises at least four vertical adsorption towers with uniform specifications, and each tower is filled with a zeolite material for carbon dioxide adsorption; the multi-tower zeolite adsorption-desorption unit operates in a'multi-adsorption + less desorption + less cooling 'dynamic alternating mode to ensure that ship tail gas continuously passes through multiple towers to realize efficient carbon dioxide capture without interruption of direct discharge; the multiple towers are arranged in a compact matrix, round or square mode matched with the space of a ship deck and integrated on the same bearing base, and the multiple towers are matched with the limited installation space of a ship. The invention provides a special multi-tower alternate CO2 capturing system which is adaptive in space, balanced in period, tolerant in working condition, low in consumption and long in acting, and the individual requirements of LNG transport ships of different specifications are met.

Description

Technical Field

[0001] This invention belongs to the field of LNG storage technology, specifically relating to a multi-tower rotating zeolite carbon dioxide capture system suitable for LNG carriers. Background Technology

[0002] With increasing pressure on carbon emission reduction in the global shipping industry, CO2 capture from the exhaust gas of LNG carriers, as the mainstay of clean energy transportation, has become an essential issue for the industry. Zeolite, due to its large adsorption capacity and good thermal stability, is currently the mainstream material for CO2 capture. However, existing multi-tower zeolite CO2 capture technology has many insurmountable defects when applied to LNG carriers, and no targeted solutions have been developed: The adsorption-desorption cycle matching is lacking: zeolite adsorption of CO2 saturates in only tens of seconds, but desorption and regeneration take tens of minutes, and the existing multi-tower scheduling logic is not designed with precise timing to address this extreme cycle difference. The 4-tower scheme is prone to adsorption interruptions due to insufficient adsorption towers. Insufficient adaptability to harsh ship operating conditions: High salt spray at sea, ±20° tilting and turbulence, and exhaust gas containing seawater droplets can easily lead to problems such as valve group corrosion and leakage, zeolite particle friction pulverization, and bed airflow deviation in existing systems; existing pretreatment systems can only perform demisting or dehumidification, and cannot simultaneously solve the needs of "demisting, desalination, and dehumidification", which exacerbates zeolite failure; and lack of dedicated anti-turbulence structure, resulting in poor stability of multi-tower operation.

[0003] In summary, existing technologies lack a dedicated solution for LNG carriers that features "multi-tower adaptive configuration, precise timing, adaptability to operating conditions, energy synergy, and fault tolerance," requiring targeted innovative design. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention provides a multi-tower rotating zeolite carbon dioxide capture system suitable for LNG carriers. The system includes a multi-tower zeolite adsorption-desorption unit, comprising at least four uniformly sized vertical adsorption towers, each filled with zeolite material for carbon dioxide adsorption. The multi-tower zeolite adsorption-desorption unit operates in a dynamic rotation mode of "more adsorption + less desorption + less cooling," ensuring that ship exhaust gas continuously passes through the multiple towers for efficient carbon dioxide capture without interruption of direct emissions. The multiple towers adopt a compact matrix, circular, or square layout adapted to the ship's deck space and are integrated on the same support base, adapting to the limited installation space on the ship.

[0005] Furthermore, the multi-tower zeolite adsorption-desorption unit is configured with 5 towers, adopting a compact matrix, circular or square layout. The material of each tower is salt spray resistant stainless steel suitable for marine environments, and the tower is filled with highly wear-resistant zeolite. The total floor area of ​​the 5 towers is adapted to the load-bearing capacity of the ship's deck, and longitudinal space is reserved to accommodate crew maintenance operations.

[0006] Furthermore, when the multi-tower zeolite adsorption-desorption unit is configured with 5 towers, the "more adsorption + less desorption + less cooling" mode is specifically a "3 adsorption + 1 desorption + 1 cooling" dynamic rotation mode. The total cycle is adapted to the difference in zeolite adsorption-desorption cycle, and the tower state is switched once every preset time interval to ensure that at any time there are 3 towers in the state of zeolite adsorption of carbon dioxide, thus ensuring continuous treatment of ship exhaust gas.

[0007] Furthermore, the multi-tower zeolite adsorption-desorption unit also includes an inlet, outlet, regeneration, and cooling main pipe adapted to ship exhaust gas delivery, as well as a leak-proof pneumatic quick-cut valve assembly; a carbon dioxide concentration sensor is installed at the outlet of each adsorption tower to accurately determine the zeolite adsorption saturation state and trigger switching; the valve assembly response speed is adapted to the fluctuation characteristics of ship exhaust gas, and the switching sequence is strictly controlled to avoid ship exhaust gas leakage.

[0008] Furthermore, it also includes an intelligent scheduling unit, which has a built-in multi-tower rotation dedicated timing program. This program collects the zeolite adsorption status, tower operating status, and ship exhaust gas parameters of each tower in real time, triggering tower adsorption-desorption-cooling state switching, emergency scheduling for abnormal situations, and a single-tower failure disconnection mechanism. When any tower fails, the program can automatically disconnect the faulty tower from the system and maintain the minimum operating mode of "less adsorption + less desorption + less cooling" by reorganizing the rotation logic of the remaining towers. This ensures continuous CO2 capture of ship exhaust gas and meets the ship's environmental emission requirements. The program is compatible with multi-tower configurations and can be adapted to the exhaust gas treatment needs of ships of different tonnages.

[0009] Furthermore, it also includes a pretreatment unit that specifically removes seawater droplets, salt particles, and impurities from ship exhaust gas, providing a clean gas source for multi-tower zeolite adsorption; the ship energy reuse unit recovers waste heat from ship engines and ship-specific cold energy to power zeolite desorption and tower cooling, and the energy distribution can be dynamically adjusted according to the remaining tower operating modes; the anti-turbulence stabilization unit ensures stable operation of the system under ship tilting and vibration conditions, avoids zeolite particle pulverization and failure, and provides structural support for the isolation of faulty towers.

[0010] Furthermore, it also includes an anti-turbulence stabilization unit, which includes an integrated damping base adapted to the vibration characteristics of the ship, an internal zeolite buffer structure, and flexible pipeline connection components; the damping base can resist the tilting and high-frequency vibration during ship navigation; the internal buffer structure prevents zeolite particles from being violently pulverized due to ship turbulence; and the flexible connection components prevent pipeline breakage caused by ship turbulence.

[0011] The acquisition method of the above system includes the following steps: Exhaust gas pretreatment: After the exhaust gas from the LNG carrier is demisted, desalinated and dehumidified by the pretreatment unit, it enters the multi-tower intake manifold. Multi-tower alternating adsorption: The main inlet pipe distributes clean exhaust gas to the towers in the adsorption state in sequence, and the zeolite efficiently captures CO2, purifying the exhaust gas to meet emission standards. Saturation switching desorption: After a certain tower triggers the saturation condition, the intelligent scheduling unit starts the switching, and the tower is connected to the regeneration loop to use waste heat to heat the gas to desorb CO2 and collect it; Post-desorption cooling: After the tower body completes desorption, it switches to the cooling circuit and uses the cold energy of LNG to cool it to the appropriate adsorption temperature; Cooling replenishment and fault reorganization: After cooling, the tower body replenishes adsorption and completes the cycle; if a tower body fault is detected, the faulty tower is immediately isolated and the remaining towers are reorganized to ensure continuous capture.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention offers precise and efficient cycle matching: the 5-tower "3 adsorption + 1 desorption + 1 cooling" timing perfectly balances the differences in adsorption-desorption cycles, ensuring a stable CO2 capture efficiency of 85-95%, with no interrupted exhaust gas emissions, meeting IMO carbon emission reduction regulations; the multi-tower scheduling logic is simple and adaptable to fluctuating ship exhaust gas flow conditions. It boasts strong stability under harsh conditions: its anti-turbulence and salt spray resistant design allows the system to operate stably in ±20° tilt and high salt spray environments, with a zeolite pulverization rate ≤0.01%; the three-stage pretreatment simultaneously addresses the needs of "demisting, desalinizing, and dehumidifying," extending zeolite lifespan by more than 50%. Energy consumption is significantly reduced: by reusing the ship's inherent energy, the system's additional energy consumption is ≤5kW, a 30-40% reduction compared to existing technologies, significantly lowering operating costs. Fault tolerance and maintenance-friendly: single-tower failures are automatically isolated and reassembled without downtime, suitable for long-term ocean-going operation; the maintenance cycle for core components is extended to more than 12 months; the multi-tower specifications are standardized, spare parts are highly interchangeable, and maintenance workload is reduced by 30%. High engineering feasibility: All components use mature industrial-grade products and can be directly integrated into the existing ship exhaust system without major modifications; the multi-tower layout is flexible and adaptable to different deck space configurations. Attached Figure Description

[0013] Figure 1 This is a schematic diagram I (circular layout) of a multi-tower layout according to an embodiment of the present invention; Figure 2 This is a schematic diagram II (square layout) of a multi-tower layout according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the running time of the present invention. Detailed Implementation

[0014] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0015] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0016] This application provides a multi-tower rotating zeolite carbon dioxide capture system suitable for LNG carriers. The core of this invention is a "multi-tower adaptive rotation system + deep adaptation to ship operating conditions," with a 5-tower rotation configuration as the baseline, and is equipped with four ship-specific auxiliary units. The specific details are as follows: This unit is the core of CO2 capture, enabling adaptive multi-tower configuration, precise timing rotation, and automatic fault reconfiguration. The specific design is as follows: (1) Multi-tower basic configuration and optional layout: It adopts a standardized vertical adsorption tower with a tower body made of 316L stainless steel and is filled with highly wear-resistant zeolite to ensure no pulverization under ship turbulence conditions; it supports a core 5-tower configuration: a compact layout with optional "2×3 matrix, circular or square" layout, which is suitable for the decks of mainstream LNG carriers; the configured towers are all integrated into the same steel structure support base, which facilitates overall fixation and maintenance.

[0017] (2) Core timing rotation logic (taking a 5-tower baseline configuration as an example): The system employs a dynamic rotation mode of "3 adsorption + 1 desorption + 1 cooling," with a total cycle time of 30 minutes. The tower state is switched every 10 minutes. Adsorption saturation is precisely determined using a dual trigger condition of "CO2 concentration threshold (≥500ppm) + time threshold (10min)," ensuring continuous adsorption from all three towers at any given time and achieving uninterrupted tail gas treatment. The specific timing sequence is as follows:

[0018] (3) Automatic fault reassembly mechanism: When any tower fails (such as valve assembly failure or abnormal pressure), the intelligent scheduling unit automatically triggers the faulty tower isolation procedure (closing the inlet and outlet valve assemblies of the faulty tower and cutting off the connection with the main pipe), and reorganizes the timing of the remaining towers: If 1 out of 5 towers fails: the remaining 4 towers automatically switch to the "2 suction + 1 stripping + 1 cooling" mode, with a collection efficiency of no less than 80% of the normal operating conditions; If 2 out of 5 towers fail: the remaining 3 towers switch to the minimum mode of "1 suction + 1 stripping + 1 cooling" to ensure continuous collection and meet basic emission requirements; Auxiliary Unit (1) Precision pretreatment unit: connected in series between the exhaust gas pipeline and the multi-tower intake manifold, adopting a "three-stage purification" structure: ① First-stage baffle demister (removes seawater droplets ≥10μm); ② Second-stage wire mesh demister (removes salt particles ≥1μm); ③ Dual-tower adsorption dryer (reduces the relative humidity of the exhaust gas to 10~15%). The dryer regenerates the heat source and reuses the residual heat after desorption, requiring no additional energy consumption, and provides a clean gas source for zeolite adsorption.

[0019] (2) Ship energy reuse unit: includes two major loops: ① Waste heat recovery loop: recovers the exhaust waste heat of the engine at 200~300℃ through shell and tube heat exchanger, heats the regenerated gas to 150~160℃, and supplies it to the desorption tower; ② Cold energy recovery loop: recovers the cold energy of LNG vaporization at -162℃, cools the cooling medium to 10℃, and introduces it into the jacket of the adsorption tower to achieve cooling; the energy distribution valve group dynamically adjusts the energy supply according to the configuration of multiple towers / fault status to ensure efficient energy reuse.

[0020] (3) Anti-bump stabilization unit: ① Integrated shock-absorbing base: Multiple towers share a steel structure base, with 4 large elastic shock-absorbing brackets installed at the bottom (shock absorption efficiency ≥90%) to resist ±20° tilt and high frequency vibration; ② Buffer structure inside the tower: The top of the zeolite bed is equipped with a pressure rod type elastic fixing device, and the bottom is equipped with a ceramic ball buffer layer to avoid zeolite pulverization caused by bumps; ③ Flexible pipeline connection: The main pipe is connected to the tower body with a temperature-resistant and pressure-resistant metal flexible hose to prevent breakage due to bumps.

[0021] (4) Intelligent scheduling unit: Built-in multi-tower adaptive timing program, which collects parameters such as the status of each tower (adsorption / desorption / cooling), CO2 concentration, pressure, and temperature in real time, triggers switching, fault isolation and reorganization; equipped with a touch screen operation terminal, supports automatic / manual dual mode, and is suitable for unmanned operation of ship engine room.

[0022] Overall Workflow (1) Tail gas pretreatment: After the tail gas of the LNG carrier is demisted, desalinated and dehumidified by the pretreatment unit, it enters the multi-tower intake manifold; (2) Multi-tower rotation adsorption: The intake manifold distributes the clean tail gas to the towers in the adsorption state according to the time sequence. Zeolite efficiently captures CO2 and the purified tail gas meets the emission standards; (3) Saturation switching desorption: After a tower triggers the saturation condition, the intelligent scheduling unit starts the switching. The tower is connected to the regeneration circuit and uses the residual heat to heat the gas to desorb CO2 and collect it; (4) Cooling after desorption: After the tower completes the desorption, it switches to the cooling circuit and uses the cold energy of LNG to cool it to the appropriate adsorption temperature; (5) Cooling replacement / fault reorganization: The tower that has completed cooling replaces the adsorption and completes the cycle; If a tower fault is detected, the faulty tower is immediately isolated and the remaining towers are reorganized to ensure continuous capture.

[0023] In summary, these are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent changes and modifications made in accordance with the scope of the present invention and the contents of the specification are within the scope of the present invention.

Claims

1. A multi-tower rotating zeolite carbon dioxide capture system suitable for LNG carriers, comprising a multi-tower zeolite adsorption-desorption unit, characterized in that: The multi-tower zeolite adsorption-desorption unit includes at least four vertical adsorption towers of uniform specifications, each filled with zeolite material for carbon dioxide adsorption. The multi-tower zeolite adsorption-desorption unit operates in a dynamic rotation mode of "more adsorption + less desorption + less cooling" to ensure that the ship's exhaust gas continuously passes through the multiple towers to achieve efficient carbon dioxide capture without direct emission interruption. The multiple towers adopt a compact matrix, circular or square layout adapted to the ship's deck space and are integrated on the same support base, adapting to the limited installation space on the ship.

2. The system according to claim 1, characterized in that, The multi-tower zeolite adsorption-desorption unit is configured with 5 towers, using a compact matrix, circular or square layout. Each tower is made of salt spray resistant stainless steel suitable for marine environments, and is filled with highly wear-resistant zeolite. The total floor area of ​​the 5 towers is adapted to the load-bearing capacity of the ship's deck, and longitudinal space is reserved for crew maintenance operations.

3. The system according to claim 2, characterized in that, When the multi-tower zeolite adsorption-desorption unit is configured with 5 towers, the "more adsorption + less desorption + less cooling" mode is specifically a "3 adsorption + 1 desorption + 1 cooling" dynamic rotation mode. The total cycle is adapted to the difference in zeolite adsorption-desorption cycle. The tower state is switched once every preset time interval to ensure that at any time there are 3 towers in the state of zeolite adsorption of carbon dioxide, thus ensuring continuous treatment of ship exhaust gas.

4. The system according to claim 1, characterized in that, The multi-tower zeolite adsorption-desorption unit also includes an inlet, outlet, regeneration, and cooling main pipe adapted to ship exhaust gas delivery, as well as a leak-proof pneumatic quick-cut valve assembly; each adsorption tower outlet is equipped with a carbon dioxide concentration sensor to accurately determine the zeolite adsorption saturation state and trigger switching; the valve assembly response speed is adapted to the fluctuation characteristics of ship exhaust gas, and the switching sequence is strictly controlled to avoid ship exhaust gas leakage.

5. The system according to claim 1, characterized in that: It also includes an intelligent scheduling unit, which has a built-in multi-tower rotation dedicated timing program. This program collects the zeolite adsorption status, tower operating status, and ship exhaust gas parameters of each tower in real time, triggering tower adsorption-desorption-cooling state switching, abnormal emergency scheduling, and single-tower failure disconnection mechanisms. When any tower fails, the program can automatically disconnect the faulty tower from the system and maintain the minimum operating mode of "less adsorption + less desorption + less cooling" by reorganizing the rotation logic of the remaining towers. This ensures continuous CO2 capture of ship exhaust gas and meets the ship's environmental emission requirements. The program is compatible with multi-tower configurations and can adapt to the exhaust gas treatment needs of ships of different tonnages.

6. The system according to claim 1, characterized in that: It also includes a pretreatment unit that specifically removes seawater droplets, salt particles, and impurities from ship exhaust gas, providing a clean gas source for multi-tower zeolite adsorption; a ship energy reuse unit that recovers waste heat from ship engines and ship-specific cold energy to power zeolite desorption and tower cooling, and the energy distribution can be dynamically adjusted according to the remaining tower operating mode; and an anti-turbulence stabilization unit that ensures stable operation of the system under ship tilting and vibration conditions, preventing zeolite particle pulverization and failure, while also providing structural support for the isolation of faulty towers.

7. The system according to claim 1, characterized in that: It also includes an anti-turbulence stabilization unit, which includes an integrated damping base adapted to the vibration characteristics of the ship, an internal zeolite buffer structure, and flexible pipeline connection components. The damping base can resist the tilting and high-frequency vibration during ship navigation. The internal buffer structure prevents zeolite particles from being violently pulverized due to ship turbulence. The flexible connection components prevent pipeline breakage caused by ship turbulence.

8. A capture method for the system as described in any one of claims 1-7, characterized in that, Includes the following steps: Exhaust gas pretreatment: After the exhaust gas from the LNG carrier is demisted, desalinated and dehumidified by the pretreatment unit, it enters the multi-tower intake manifold. Multi-tower alternating adsorption: The main inlet pipe distributes clean exhaust gas to the towers in the adsorption state in sequence. Zeolite efficiently captures CO2 and purifies the exhaust gas to meet emission standards. Saturation switching desorption: After a certain tower triggers the saturation condition, the intelligent scheduling unit starts the switching, and the tower is connected to the regeneration loop to use waste heat to heat the gas to desorb CO2 and collect it; Post-desorption cooling: After the tower body completes desorption, it switches to the cooling circuit and uses the cold energy of LNG to cool it to the appropriate adsorption temperature; Cooling replenishment and fault reorganization: After cooling, the tower body replenishes adsorption and completes the cycle; if a tower body fault is detected, the faulty tower is immediately isolated and the remaining towers are reorganized to ensure continuous capture.

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