Layout Optimization Of FPSO Gas Detectors Based On Leakage Risk

Oil and gas leakage accidents often occur to the operation of FPSO(floating production,storage and offloading unit).The topside modules of FPSO are closely arranged,and the processing facilities are mostly high temperature and high pressure.As a result,when oil and gas leakage accident occurs,it is easy to escalate into fire and explosion accident,which poses great threat to personnel and equipment safety.Gas detector is the first step of FPSO fire and gas detection system to identify the leakage accident.Improving the detection performance of gas detector is of great significance to control the leakage risk.Relying on the project "Research and Development of FPSO Failure Database and Risk Assessment System" of the Ministry of Industry and Information Technology,a certain FPSO in the South China Sea is taken as the analysis object to identify and evaluate the equipment leakage risk.The paper explores the law of leakage gas diffusion,and provides support for risk control and safe production by optimizing the arrangement of FPSO gas detectorsThis paper aims to improve the detection rate of leakage scenarios and reduce the cumulative risk value.This paper studies the theory of overall layout optimization of gas detectors and optimizes the layout of detectors in typical FPSO regions.The main content of this thesis is as follows:(1)Based on the analysis of material composition,production environment and other characteristics of each process module of FPSO,the advantages and disadvantages of different types of gas detectors and their applicable scope are compared,and the selection suggestions for topside module detectors are provided.(2)The topside modules of FPSO are hierarchically divided according to the process flow,and a fuzzy comprehensive evaluation method based on hierarchical analysis is introduced to evaluate the leakage risk of the upper modules.The risk weighting factor of each subsystem is evaluated,and the oil treatment system with the highest risk weighting value is selected for detector layout optimization.Combined with the production equipment table and process flow chart,the type of leaking equipment and potential leaking gas are summarized.OREDA database and related leak statistics are used to calculate the probability density distribution and cumulative probability density distribution of leak source variables and environment variables.(3)A typical gas leakage diffusion model is established based on star-ccm+software to analyze the methane diffusion law and the change law of the detector's farthest alarm distance;The typical FPSO leakage condition was simulated,the influence of different leakage parameters on the leakage consequence was analyzed,and the action mechanism of each factor on the leakage diffusion consequence was summarized.(4)Based on the probability density distribution by Latin hypercube sampling build potential leakage scenario set.The detector detection alarm time is selected as the effective detection time.The effective detection range of leaking gas was selected as the evaluation standard for the leakage consequences.The minimum sum of the product of effective detection time and effective detection range of all scenarios is selected as the risk optimization goal,the placement position and number of detectors are taken as decision variables,and the greedy dropping heuristic algorithm is adopted to solve the optimization mathematical model.(5)Taking the layout of gas detectors in the area of FPSO crude oil processing module as an example,the layout scheme for candidate detectors is determined.According to the simulation of computational fluid dynamics(CFD)software,the effective detection time and effective detection area of each leakage scenario are record.The mathematical optimization model is solved on Lingo mathematical programming software,and the layout schemes are evaluated from the perspective of risk reduction and economy.When the number of detectors is the same,the leakage scenario detection rate of the optimized layout scheme is increased by 10%and the cumulative risk value is reduced by 42.7%.The comparison between the optimized layout scheme and the field layout scheme indicates that the optimized layout scheme has a better detection effect on the leakage scenario set.