Risk Assessment And Management Strategy Of Transporting LNG Mobile Tanks By Ship On The Recovery Process

The new era is an era of green development and scientific development.With the continuous deepening of the concept of environmental protection,new energy sources that are safe,scientific,green and economic are increasingly valued by the government and favored by the market.Liquefied Natural Gas(LNG),as an emerging green energy,has attracted great attention,and countries have successively purchased LNG for their own energy applications and reserves.In recent years,LNG mobile tanks,as a new mode of LNG transportation,have attracted widespread attention around the world.At present,the transportation of LNG movable tanks in my country is mainly by road and rail,and the transportation volume is small.If the Grand Canal,Yangtze River and other water systems are used to make use of the high efficiency of inland water transportation,only "one loading and one unloading" is required in the entire transportation process to achieve "door-to-door service","full sealing" and "one tank to the end".It is in this context that relevant experts have proposed the inland waterway transportation mode of LNG portable tanks.Most of the safety research on transportation focuses on the use and transportation stage,among which the water transportation and recovery stage of LNG portable tanks is an important stage of LNG portable tank transportation,and there is a certain degree of blank in the relevant safety research in this stage.This paper studies the safety of transportation in the waterway recovery stage,which is a supplement to the overall transportation safety of my country’s waterway LNG portable tanks,and can effectively promote the development of multimodal transportation of LNG portable tanks in my country.This paper conducts research in the following aspects:(1)This paper analyzes the factors that affect safety in the process of water transportation recycling,inquires about the laws,regulations and industry standards related to the manufacture and transportation of LNG portable tanks,and learns about LNG portable tanks by investigating relevant manufacturing units and transportation companies.Dangers such as LNG leakage or tank falling may occur during transportation,and various reasons that may cause dangers are analyzed and analyzed using the accident tree analysis method.The results show that attention should be paid to the isolation and control of ignition sources when LNG mobile tanks are recovered and transported.Attention should be paid to the securing and lashing of LNG mobile tanks and the safe operation of personnel to avoid tanks from falling.At the same time,attention should be paid to LNG evaporation.And the safety valve of the movable tank is in good condition to avoid the phenomenon of LNG leakage caused by the damage of the safety valve due to excessive pressure inside the tank.(2)Taking the whole system of LNG mobile tank container water transportation recycling and transportation as the research object,using the method of system dynamics to study the actual risk of recycling and transportation.This paper first divides the whole system of LNG mobile tank tank water recycling and transportation into two parts: inherent hazard system and offset system.It is further refined into 5 major subsystems,among which the inherent hazard system includes transport material hazard and ship hazard;the offset system includes: safety management offset,personnel quality offset,process and equipment offset.According to the actual hazard evaluation method based on major hazard sources,the system dynamics model of the water transport recovery process of LNG portable tanks is established,and the scoring standards for related elements are established.Realistic simulation is carried out according to the system dynamics simulation software,relevant data is obtained,and the data is analyzed to study the influence of various influencing factors on the safety of the transportation system.Know that the human factor is the determinant of the hazards of transport operations.The actual danger increases with the increase of time.At a low filling rate,the actual danger is directly related to the filling rate,and the actual danger is the greatest when the filling rate is 3%.(3)In order to further study whether the pressure and temperature changes inside the LNG movable tank will cause harm to the movable tank itself when the filling rate is 3%,according to the principle of heat transfer,the heat transfer situation is analyzed,and ANSYS Fluent professional transfer is used.Thermal software builds a model of a single LNG movable tank.Research shows that when the filling rate is 3%,the maximum pressure of the movable tank is less than the set pressure of the safety valve,and it will not break through the safety valve and leak.(4)In order to effectively ensure the safety of the recycling and transportation of LNG movable tanks,from the two aspects of avoiding the occurrence of accidents as much as possible and trying to control and reduce the adverse consequences after the occurrence of accidents,it is proposed to include entertainment for the crew’s body and mind.security measures.This paper comprehensively studies the types of hazards that may occur in the recycling of LNG mobile tanks and the reasons for the hazards.And from the whole to the part,the risk of the recovery and transportation process and the risk of a single LNG movable tank are respectively studied.Combining the pressure change in the LNG tank with the recovery and transportation process,the influence of the low filling rate of LNG on the safety of the entire system is studied from the overall point of view.A computational fluid dynamics(CFD)model for LNG portable tanks was constructed to study the impact of low filling rate on the safety of portable tanks.It plays a certain role in improving the design safety of LNG movable tank and developing inland water transportation.