Layout Optimization And Design Of Small Hydrogen Fuel Cell Ship Risk Analysis Of Hydrogenation Station

In recent years,due to the increasing environmental pollution caused by the excessive use of fossil fuels,it is imperative to shift energy demand to renewable energy based on solar energy,biomass energy,wind energy and hydrogen energy.Hydrogen is currently the only zero-emission fuel and is recognized as a clean energy source.It has the characteristics of environmental protection,good combustion and convenient transportation.The hydrogen energy industry represented by hydrogen fuel cells is becoming more and more closely integrated with ships.However,hydrogen is a flammable gas with low density,high leakage and diffusion tendency,and the limit concentration range of ignition is wide from 4 % to 75 %.It is easy to explode in open fire,and the destructive power is much larger than that of traditional fuel,so the risk of accident is higher.At present,there are potential safety hazards in the way of hydrogen fuel storage,which limits the development of hydrogen.Once hydrogen leakage occurs in a hydrogen fuel cell ship or a marine hydrogenation station,the leakage cloud will easily lead to serious consequences of combustion and explosion accidents when it encounters an ignition source.Therefore,as a new type of energy engineering,it is of great significance to study hydrogen leakage and diffusion and combustion explosion accidents for setting safe distance and reducing accident damage.The main work of this thesis is as follows:(1)According to the existing design scheme of lithium battery powered ship,the layout of lithium battery powered ship is optimized and upgraded to the layout of hydrogen lithium battery hybrid powered ship.A hybrid layout scheme of hydrogen lithium battery and heat dissipation ventilation system of battery cabin are designed.Hydrogen fuel cell technology is used to improve the endurance and reduce the pollution to the environment.The safe heat dissipation ventilation system in the cabin of the hydrogen fuel cell ship provides a good heat dissipation ventilation environment for the small hydrogen fuel cell ship,releases the additional calorific value of the hydrogen fuel combustion,and considers the energy saving effect to reduce the useless consumption of the ship equipment.While ensuring the normal navigation of the hydrogen fuel cell ship,the heat dissipation efficiency is increased through the whole ship circulation ventilation,and the overall operation energy consumption cost is reduced.In the event of a sudden hydrogen accident,emergency ventilation can be performed in time to dilute the hydrogen concentration in the cabin to prevent the hydrogen accident from further expanding.(2)Based on FLACS software,a simplified model of hydrogen fuel cell ship and marine water hydrogenation station is established by numerical simulation.The transient leakage process of hydrogen storage tank is simulated when the ship is docked and filled.The variation of hydrogen leakage diffusion,combustion heat radiation and explosion overpressure is analyzed.It is found that the building hinders the flame radiation.The hydrogen combustion explosion will release a lot of energy in a short time,produce high temperature and high pressure gas,and the air around the explosion object is rapidly heated and expanded to form a shock wave.This shock wave will spread outward,and the influence area reaches half of the area of marine water hydrogenation station.With the expansion of the influence range,the explosion overpressure value gradually decreases.The effective coverage of the existing hydrogen concentration detector in the hydrogenation station is simulated.In the simulation of six leakage conditions,it is found that the effective coverage of the existing detector is only 60 % lower than 80 % of the national standard.According to the CFD simulation results,the position of the existing detector is optimized.After optimization,the effective coverage is more than 90 % in line with national safety standards.(3)Based on PHAST software,the simulation of hydrogen leakage diffusion and ignition explosion accident is carried out.The quantitative risk assessment QRA method is used to obtain the numerical simulation results.Taking 2 meters as the observation height,from the analysis of leakage diffusion degree,for the lower limit of hydrogen 4 % ignition explosion concentration,the wind speed of 12 m / s has the greatest influence on the accident.The leakage distance of the 4 % concentration lower limit of the long tube hydrogen storage tank is 41.06 meters,and the 4 % concentration lower limit of the distributor is 71.90 meters.Taking the minimum thermal radiation damage value of 4k W / m2 as the lower limit,the farthest influence distance of fire accident of long tube hydrogen storage tube is 20.65 meters,and the farthest influence distance of fire risk of distributor is 35.62 meters.With the minimum overpressure damage value of 0.02 bar as the lower limit,the farthest influence distance of the explosion accident of the long tube hydrogen storage tank is 49.65 meters,and the farthest influence distance of the explosion accident of the distributor is 55.16 meters.In this thesis,the quantitative risk assessment of hydrogen storage tank and marine hydrogen refueling station of hydrogen fuel cell ship is carried out.The law and influence range of the accident are studied by means of two-dimensional and three-dimensional combination.The influence range and safety distance of hydrogen accident are obtained,which provides a reference for the location of marine hydrogen refueling station and the arrangement of hydrogen concentration detector.