Numerical Simulation And Optimization Of Tension Schemes Of Large LNG Storage Tank’s Outer Wall Prestressing Tendons

With the constant climatic deterioration and the declining air quality, all countries seem to think highlyof the natural gas day by day which is acted as a kind of clean energy. China’s The Twelfth FiveYears’Planning of The Natural Gas Development points out natural gas is a kind of high quality low carbonenergy that is efficient and clean. Speeding up the development of natural gas industry and improving itsproportion in primary energy consumption have important strategic significance to our adjustment ofenergy structure, the improvement of people’s living level, the promotion of energy-saving andenvironmental protection and the response of changing climate. Comparing with pipeline gas,LNG(Liquefied Natural Gas) is faster and more flexible as well as avoiding the obstruction of pipelinestrides different countries’ jurisdictions, therefore, LNG prestressing storage tank’s appearance anddevelopment has vital significance.At present, both home and abroad have not so much research on the outer tank of large-scale LNGtank and much less on outer tank’s prestressing tendons technology. Large-scale LNG storage ofprestressing tendons in china is according to abroad design company’s guidance or depends on experienceto carry out, without the analysis of systematic reasonable force and deformation. Therefore, large-scaleLNG storage of prestressing tendons technology is a worth studying problem.This article is based on Shandong liquefied natural gas project which is large-scale ground capacitivestorage tank of China Petroleum Chemical Co,utilizing finite element software ANSYS to analyse LNGconcrete tank’s prestressing tendons. The main work is as follows:1. Take advantage of finite element software ANSYS to establish finite element model of concreteouter tank. The exertion of prestressing force comes true through falling temperature method. Adopting lifeand death technology of unit element to eliminate the effect of concrete iron which is not imposedprestressing force on model analysis.2. According to symmetric interval tension principle to put forward four kinds schemes of overalltension firstly and carry out numerical simulation. The drawing of a conclusion by comparative analysis of the tensioning process of the stress and deformation of outer tank from the four schemes that at the time oftensioning of prestressing force, vertical prestressing bar shoulded be first tensioned, then thecircumferential tendons.3. When simulating the tension of vertical prestressing bar, the pulling stress in the end position ofouter tank will come into being, in view of this situation, proposing a prioritization scheme in which aftertensioning a portion of the vertical prestressing bar then to tension circumferential tendons to decrease thepulling stress of telos, through the continuous optimization and define the vertical prestressing bar schemefinally.4. Simulate and analyse two schemes of tensioning circumferential tendons that from top to bottomand from bottom to top. Through comparing the two schemes of tensioning process of the stress anddeformation of outer tank draws the conclusion that the scheme tensioning circumferential tendons frombottom to top is better then the other scheme, but the difference is very small. From the point of view ofconstruction, tensioning circumferential tendons from top to bottom is more reasonable.