A Study On Large Capacity Vertical Storage Tank Measurement And Software Development

Large capacity vertical storage tank(LCVST)is a type of measurement instrument which widely applies to international petrochemical products trades.For this purpose,its measurement accuracy affects national economic interests and metrology reputation directly.The conventional method of capacity measurement in LCVST is imperfect with low accuracy,high cost and dangerous operations.Additionally,Since the volume calculations execute artificially,it will take a long time to work out and introduce some errors.Therefore,how to measure capacity of LSVST more precisely become the urgent problems to be solved in petrochemical industry.Firstly the paper set to study data capture method for LCVST.According to the structure of LSVST,the measurement methods of tank walls and tank bottoms are primary studied.The paper presents applying three-dimensional laser scanner to tank walls measurement and geometric leveling method to tank bottoms measurement.Contrast to conventional measurement method the paper's gets a more precise result.And it contributes in providing more reliable data to the following capacity calculation.Nextly a study has been set to point cloud pre-processing technologies of tank walls.For the purpose of obtaining uniform point cloud model from variety of stations,the paper presents a method to merge them sequentially base on theory of three-point matching.After this,procedures of noise reduction and data simplified have been applied to the merged point cloud for the sake of denoising and reducing data redundance.These two procedures play an important part in making capacity calculations more efficiently and precisely.Then research and implement on capacity calculations with a method of tank walls slice-process are carried out.The main steps are summarized as follows:separated tank wall into a series of chips alone the vertical direction;obtain each chip's point cloud of its cross section through the section extract-process;solve the radius of cross section circle and circle center by the least-squares method;calculate capacity and effect of static water.Through the work above the arbitrary capacity in the interval of work storage capacity and total capacity are able to obtained.Lastly A software aiming to process point cloud data and calculate capacity of LCVST has been developed,which contains data pre-processing module;volume calculations module;capacity table output module.The software also introduce some features as follows:supports SQL Server Database;deal with denoising and data simplifying more efficiently;fully work storage volume calculation includes counterpart capacity of arbitrary height;capacity table file export through Excel with multiple form selection.Base on the running instance it demonstrates that the software is functional,easy-operation,stable and capable of overcoming the problems existing in present LSVST volume measurement technologies.