Ultra-large LNG Storage Tank And Storage Farm Safety Performance-based Design Technology Research

Liquefied natural gas as a kind of new energy, it is widely used in the field of chemical,living and automobile fuel with its clean, economical and efficient characteristics. With thegrowing of demand of society and development of LNG industry, the size of LNG storagetank presents the trend of large-scale and develops ultra-large storage tank, it has become aninevitable development direction. However, large-scale liquefied natural gas gathers instorage and tank farm, it will result in significant casualties and property losses in the event ofleakage fire explosion accident. Therefore, the safety design of ultra-large storage tank andtank farm is in-depth studied to prevent or mitigate the effect of fire and explosion, which hasgreat significance to promote the long-term development of LNG industry.At present, LNG standardization construction is still in the stage of development inChina, the experience of large-scale production and storage LNG is less in domestic, andthere isn’t a set of mature standard specification suitable for ultra-large storage tank and tankfarm. So the paper fully learn the design experience of LNG storage tank and tank farm athome and abroad and integrate into the performance-based design concept, which aims toform a system of safety design process for ultra-large storage tank and tank farm. Firstly, thepaper analyzes the risk of LNG and in the process of LNG storage and targets safety designfor storage tank, select storage tank type suitable for bulk storage of liquefied natural gas andthe type of material suitable for direct contact with liquefied natural gas, and design tankinstrumentation system. Secondly, the thesis comes up with performance-based risk analysisprocedure for LNG tank farm, has clear the provisions of contents about two standards forLNG storage tank fire protection distance with reference to standards of NFPA59A-2009andEN1473-2007, forms LNG storage tank farm layout design combined with theperformance-based design technology and NFPA59A-2009and EN1473-2007provisions ofdetermination of tank fire separation. Then, the thesis establishes performance-based riskanalysis program suitable for LNG tank farm and surrounding area combined with QRA riskanalysis technology and regional risk superposing principle, index of risk assessment (RAC)matrix method is used to filter greater level risk accident from LNG storage tank, works out risk acceptance criteria applicable to Chinese LNG station, analysis the calculation processand effectiveness of DNV SAFETI software. Finally, performance-based safety designtechnology for LNG storage tank is done in instance application studies, it uses NFPA59A-2009based on the means of accident consequences and EN1473-2007based on riskassessment method according to the process of performance-based design, respectivelyconsidering storage tank pool fire and discharging pipe50mm diameter hole leakage fire asaccident scenario to determine tank fire separation to guide the completion of instance LNGstorage tank farm design layout; on the basis, apply SAFETI software to calculatesuperposing risk of the accident of unloading pipeline leakage in LNG storage tank farm,draw the conclusion that the individual and social risk of LNG terminal station andsurrounding area is in the acceptable area, indicating instances LNG storage tank farm layoutplanning and design can satisfy the requirement for public safety, and put forwards furthersuggestion to improve the risk level of receiving area.