半地下坐地式LNG储罐电伴热系统的设计

Design of electric tracing system for semi-buriedfloor-mounted LNG storage tanks

相较于传统架高式液化天然气(Liquefied Natural Gas, LNG)储罐,坐地式或半地下坐地式LNG储罐因采用低承台结构,本体的一部分会与周围土壤直接接触,且无空气流通空间,储罐内部的低温将通过储罐本体传导至罐外,影响储罐周围土壤温度;当土壤温度≤0℃时,土壤冻胀隆起,导致储罐受力不均。针对这一问题,首先分析了LNG储罐保冷结构,研究了不同保冷材料的导热系数,计算出储罐不同位置处的漏热量,并根据计算结果选择电伴热系统设计方案,最后采用软件建模仿真分析,进一步验证电伴热系统设计的合理性。电伴热系统可消除低温对储罐周围土壤造成的影响,且能保证储罐本体温度的一致性和连续性,有效避免罐内LNG沸腾。研究成果可为半地下坐地式LNG储罐在进行电伴热系统设计时提供借鉴。

Compared to traditional elevated LNG storage tanks,floor-mounted or semi-buried floor-mounted LNG storage tanks adopted low platform structure,with parts of the tank in direct contact with the surrounding soil and has no space for air circulation.The low temperature inside the tank is conducted through the tank body to the outside,thereby affecting the temperature of the soil around the tank.When the soil temperature is≤0℃,it can cause soil frost heave and uplift,leading to uneven stress on the tank.To address this issue,this paper first analyzes and discusses the tank s cold insulation structure,and then studies the thermal conductivity of different insulation materials for calculating the heat leakage at various locations of the tank.An electric tracing system design scheme is then selected based on these calculation results.Finally,software modeling and simulation analysis are used to further verify the rationality of the electric tracing system design.This system can eliminate the impact of low temperature on the soil around the tank and ensure the consistency and continuity of the tank s body temperature,effectively preventing the boiling of LNG inside the tank.The research findings can provide reference and guidance for the design of electric tracing systems for semi-buried floor-mounted LNG storage tanks.