Ship liquid ammonia fuel pipeline purging system

Abstract

A ship liquid ammonia fuel pipeline purging system is characterized in that a liquid ammonia storage tank is sequentially connected with a liquid ammonia fuel supply unit, a liquid ammonia fuel valve group and an engine through pipelines, and the engine is sequentially connected with the liquid ammonia fuel valve group and a liquid ammonia pressure stabilizing buffer tank through pipelines and then returns to the liquid ammonia fuel supply unit. The nitrogen generator is sequentially connected with the low-pressure nitrogen storage tank, the nitrogen pressurizing unit and the high-pressure nitrogen storage tank through pipelines, and the high-pressure nitrogen storage tank is respectively connected with the engine, the liquid ammonia fuel valve group, the liquid ammonia fuel supply unit and the liquid ammonia pressure-stabilizing buffer tank through pipelines. The top of the liquid ammonia fuel valve group is connected with the ammonia water dilution unit through a pipeline, and an ammonia gas concentration sensor is arranged on a passage from the liquid ammonia fuel valve group to the ammonia water dilution unit. Ammonia fuel in the fuel pipeline can be effectively recycled and reused, secondary high-temperature low-pressure nitrogen purging is more beneficial to sweeping and treatment of residual ammonia liquid or ammonia gas in the pipeline, and operation of the system is effectively guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of marine vessel design and construction, and specifically relates to a liquid ammonia fuel pipeline purging system for ships. Background Technology

[0002] Liquid ammonia fuel, as a zero-carbon, low-flash-point fuel, has gradually begun to be used in the shipping industry. To ensure the safe and stable operation of low-flash-point fuel systems, it is necessary to effectively control the diffusion area of ​​liquid ammonia or ammonia gas to reduce the risk of accidents.

[0003] When the engine switches from liquid ammonia fuel supply to conventional fuel supply or stops running, residual ammonia in the liquid ammonia fuel supply line must be drained or purged to reduce the concentration of ammonia in the fuel line and prevent secondary accidents such as fire or poisoning. When the ammonia-fueled engine stops or switches from ammonia fuel to fuel mode, the liquid ammonia fuel supply system stops operating, and the fuel supply valve is shut off to prevent leakage or explosion of residual ammonia in the line and reduce the risk of accidents. Summary of the Invention

[0004] To solve the above problems, the present invention provides a ship liquid ammonia fuel pipeline purging system, the technical solution of which is as follows:

[0005] A marine liquid ammonia fuel pipeline purging system is provided, wherein a liquid ammonia storage tank is connected in sequence to a liquid ammonia fuel supply unit, a liquid ammonia fuel valve group, and an engine via pipelines, and the engine is connected in sequence to a liquid ammonia fuel valve group and a liquid ammonia pressure stabilizing buffer tank via pipelines, and then returns to the liquid ammonia fuel supply unit.

[0006] The nitrogen generator is connected in sequence to the low-pressure nitrogen storage tank, the nitrogen booster unit, and the high-pressure nitrogen storage tank via pipelines. The high-pressure nitrogen storage tank is connected to the engine, the liquid ammonia fuel valve group, the liquid ammonia fuel supply unit, and the liquid ammonia pressure stabilizing buffer tank via pipelines. A first branch pipeline extends from the passage from the low-pressure nitrogen storage tank to the nitrogen booster unit, and the first branch pipeline is connected to the liquid ammonia fuel supply unit, the liquid ammonia fuel valve group, and the engine.

[0007] The top of the liquid ammonia fuel valve assembly is connected to the ammonia dilution unit via a pipeline, and an ammonia concentration sensor is installed on the passage from the liquid ammonia fuel valve assembly to the ammonia dilution unit.

[0008] Furthermore, in the aforementioned ship liquid ammonia fuel pipeline purging system, a liquid ammonia transfer pump is installed inside the liquid ammonia storage tank, and the discharge pressure of the liquid ammonia transfer pump is 4 bar.

[0009] Furthermore, in the aforementioned ship liquid ammonia fuel pipeline purging system, a shut-off valve is installed on the passageway from the liquid ammonia storage tank to the liquid ammonia fuel supply unit.

[0010] Furthermore, in the aforementioned ship liquid ammonia fuel pipeline purging system, a pressure regulating valve and a heater are sequentially installed on the first branch pipeline.

[0011] Furthermore, in the aforementioned marine liquid ammonia fuel pipeline purging system, the pressure of ammonia fuel entering the engine is 85 bar, and the temperature is 35-45°C.

[0012] Furthermore, in the aforementioned marine liquid ammonia fuel pipeline purging system, the heat source for the heater is either an electric heater or steam.

[0013] The beneficial effects of this invention are:

[0014] 1. Based on the design pressure of the fuel pipeline, a two-stage purging method using high-pressure nitrogen and low-pressure nitrogen is adopted. The first stage of high-pressure nitrogen purges the ammonia liquid to the buffer pressure stabilizing tank, which can effectively recover and reuse the ammonia fuel in the fuel pipeline. The second stage of high-temperature low-pressure nitrogen purging is more conducive to the cleaning and treatment of residual ammonia liquid or ammonia gas in the pipeline.

[0015] 2. Taking advantage of the volatile nature of liquid ammonia fuel, a nitrogen heating device is installed. The heated low-pressure purging nitrogen is more conducive to the volatilization of residual ammonia liquid on the pipe wall and the treatment of ammonia-containing mixed gas after purging.

[0016] 3. Taking advantage of the fact that ammonia is easily soluble in water, the ammonia-containing mixed gas after low-pressure nitrogen purging is connected to the ammonia water dilution treatment unit to treat the ammonia. An ammonia detection sensor is installed at the end of the purging pipeline to effectively ensure the operation of the system. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the system of the present invention;

[0018] Among them: 1-Nitrogen generator, 2-Low-pressure nitrogen storage tank, 3-Nitrogen pressurization unit, 4-High-pressure nitrogen storage tank, 5-Heater, 6-Liquid ammonia storage tank, 7-Liquid ammonia transfer pump, 8-Liquid ammonia pressure stabilizing buffer tank, 9-Liquid ammonia fuel supply unit, 10-Liquid ammonia fuel valve group, 11-Engine, 12-Ammonia water dilution unit, 13-Ammonia concentration sensor, 14-Pressure regulating valve, 15-Second branch, 16-First branch. Detailed Implementation

[0019] The invention will be further described with reference to the accompanying drawings.

[0020] like Figure 1 As shown, a marine liquid ammonia fuel pipeline purging system is provided, in which liquid ammonia fuel is supplied from the fuel storage tank via a liquid ammonia fuel supply unit, fuel valve assembly, and pipelines to the engine. When the engine needs to be stopped or the fuel mode needs to be switched, the liquid ammonia in the fuel supply pipeline needs to be effectively purged.

[0021] Liquid ammonia fuel is transported from the liquid ammonia storage tank to the liquid ammonia fuel supply unit via a liquid ammonia transfer pump. The discharge pressure of the liquid ammonia transfer pump is 4 bar. The liquid ammonia is pressurized and heated by the liquid ammonia fuel supply unit to meet the engine's ammonia fuel inlet pressure and temperature requirements (pressure 85 bar and temperature 35-45℃). After passing through the liquid ammonia fuel valve assembly, it enters the engine for combustion. A liquid ammonia pressure stabilizing buffer tank is installed between the liquid ammonia storage tank and the liquid ammonia fuel supply unit to stabilize the pressure in the supply system and recover liquid ammonia from the fuel pipeline.

[0022] The nitrogen generator produces low-pressure nitrogen (approximately 10 bar) to a low-pressure nitrogen storage tank. The nitrogen in the storage tank is divided into two branches. The first branch is used for low-pressure purging of the fuel pipeline. The second branch is pressurized to 30 bar by a nitrogen booster unit before entering the high-pressure nitrogen storage tank.

[0023] The purging process is as follows:

[0024] 1. When the liquid ammonia fuel supply system stops operating, the liquid ammonia in the fuel supply pipeline is first purged by high-pressure nitrogen (30 bar) from the nitrogen storage tank via a second branch. This initial high-pressure nitrogen purging is more effective in removing a large amount of liquid ammonia from the pipeline. The high-pressure nitrogen purging can be repeated twice to purge most of the liquid ammonia in the fuel pipeline back to the ammonia pressure stabilizing buffer tank. Simultaneously, the liquid ammonia in the pressure stabilizing buffer tank can be used as fuel to supply the engine.

[0025] 2. A large amount of liquid ammonia in the fuel pipeline is purged with high-pressure nitrogen, and then purged with low-pressure nitrogen from the first branch. The nitrogen from the low-pressure storage tank outlet is depressurized by a pressure regulating valve and heated by a heater before being connected to the fuel pipeline for purging. The high-temperature nitrogen flow through the pipeline helps the residual liquid ammonia on the inner wall of the pipeline to evaporate into ammonia gas, making it easier to effectively remove the gas from the pipeline. The heat source for heating the low-pressure nitrogen can be an electric heater or steam.

[0026] 3. The ammonia-containing mixed gas purged with low-pressure nitrogen is connected to the ammonia dilution unit. The ammonia in the lower-pressure ammonia-containing mixed gas is more easily treated and dissolved in water. An ammonia detection sensor is installed at the end of the pipeline connected to the dilution unit. If the concentration is detected to be too high, the low-pressure nitrogen can be purged repeatedly to ensure that the ammonia in the pipeline is effectively removed.

Claims

1. A purging system for a ship's liquid ammonia fuel pipeline, characterized in that, The liquid ammonia storage tank is connected in sequence to the liquid ammonia fuel supply unit, the liquid ammonia fuel valve group, and the engine via pipelines. The engine is connected in sequence to the liquid ammonia fuel valve group and the liquid ammonia pressure stabilizing buffer tank via pipelines, and then returns to the liquid ammonia fuel supply unit. The nitrogen generator is connected in sequence to the low-pressure nitrogen storage tank, the nitrogen booster unit, and the high-pressure nitrogen storage tank via pipelines. The high-pressure nitrogen storage tank is connected in sequence to the engine, the liquid ammonia fuel valve group, the liquid ammonia fuel supply unit, and the liquid ammonia pressure stabilizing buffer tank via pipelines. A first pipeline extends from the passage from the low-pressure nitrogen storage tank to the nitrogen booster unit, and the first pipeline is connected to the liquid ammonia fuel supply unit, the liquid ammonia fuel valve group, and the engine. The top of the liquid ammonia fuel valve assembly is connected to the ammonia dilution unit via a pipeline, and an ammonia concentration sensor is installed on the passage from the liquid ammonia fuel valve assembly to the ammonia dilution unit.

2. The ship liquid ammonia fuel pipeline purging system according to claim 1, characterized in that, The liquid ammonia storage tank is equipped with a liquid ammonia transfer pump, and the discharge pressure of the liquid ammonia transfer pump is 4 bar.

3. A shipboard liquid ammonia fuel pipeline purging system according to claim 1, characterized in that, A shut-off valve is installed on the passageway from the liquid ammonia storage tank to the liquid ammonia fuel supply unit.

4. A shipboard liquid ammonia fuel pipeline purging system according to claim 1, characterized in that, The first branch pipeline is equipped with a pressure regulating valve and a heater in sequence.

5. A shipboard liquid ammonia fuel pipeline purging system according to claim 1, characterized in that, The pressure of ammonia fuel entering the engine is 85 bar, and the temperature is 35-45°C.

6. A shipboard liquid ammonia fuel pipeline purging system according to claim 4, characterized in that, The heat source for the heater is either an electric heater or steam.

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