Research On Ballast Water Allocation Scheme Optimization Of Full-revolving Floating Crane

Floating crane is a key equipment of rescue,salvage and large-scale offshore projects.With the operation complexity and large scale of offshore engineering,the floating crane tends to be heavy-duty,deep and efficient.And higher requirements are put forward for its lifting capacity,efficiency,stability and security.Ballast system and its ballast water allocation decisions are the key issues for floating cranes' working efficiency and safety.In this paper,on the basis of analyzing the typical working conditions and operation characteristics of full-revolving floating cranes,the optimization model of ballast water allocation is established.Based on the optimization solving of a specific project case,the influences of initial ballast water loading volume and ways on optimization results are analyzed.The main contents include:Firstly,the typical working conditions and running ways of floating cranes are analyzed.Taking the typical rotating motions as the research objection,the ballast water allocation optimization model is established,which lays the foundation for the optimization of ballast water allocation scheme.In this model,the minimization of the ballast water allocation volume during working process is taken as the optimization objective.And the hull stability requirements during construction,ballast water loading restrictions and the initial stowage ways are taken as the constraint functions.Secondly,for a specific engineering case,the ballast water allocation optimization scheme is obtained by solving the optimization model.The optimization scheme is compared with the one obtained by the engineering experience.The analysis results show that the ballast water allocation volume is reduced by 21%after optimization.In addition,the influence rules of ballast water loading ways and volumes on the allocation volume are analyzed.And the results show that(1)larger ballast water loading volume can get a smaller allocation volume within a certain range when other conditions are certain;(2)under same conditions,the ballast water allocation volume is smaller when the proportion of the ballast water in the cabins of the bow and stern;(3)The allocation volume can sharply change when the ballast tanks are emptied during working.Finally,based on the ballast water allocation optimization model,the design scheme of the ballast water allocation system is proposed,which can provide theoretical supports for building automatic ballast system.In addition,for the specific floating crane,the ballast pipes and the remote control system of ballast piping valves and ballast pumps are designed and selected so as to meet the working requirements of the floating crane.This paper can provide theoretical and technical supports for selecting the optimal ballast water allocation scheme and building the automatic ballast system to improve the working efficiency and reduce the energy consumption of floating cranes.