Research On Alarm Management Of Diesel Hydrogenation Unit Based On Risk Mapping Method

Generally speaking,there are many problems in petrochemical plants,such as too optional DCS parameter alarm setting,too unreasonable alarm settings,and low alarm system function.They bring the problem about false alarm,missing report and alarm overflow.Too high alarm rate reduces operator's attention to the probability of important alarm,so that they can't respond effectively to key alerts,or even be competent for warning tasks.This phenomeno makes a large number of inputs and functions of the alarm function idle,which brings great hidden danger to the safety production facility of petrochemical plants.In this paper,the diesel hydrogenation unit is taken as the research object,and the research results obtained are as follows:In view of the poor operability of the current mainstream alarm priority setting method,the priority of the alarm system can not be optimized because of the lack of consideration dimension.To solve the problem,a new alarm priority setting method was established based on the risk.The calibrated risk graph method is applied to the alarm priority setting With assumpation an alarm does not exist,the frequency of dangerous situations,the severity of consequence,the available time and the possibility of avoid accident consequences are calibrated.The frequency and the available time of the dangerous situation are analyzed by matrix,and the results are applied to the risk map.The method is applied to the optimization of an alarm system of a diesel hydrogenation unit,and the result is close to the recommended proportion in EEMUA.The problem of poor operation and optimization difficulties are solved.In view of the lack of effective means to evaluate the performance level of the current diesel hydrogenation unit alarm system,a method to evaluate the alarm priority and key performance indicators is proposed.By comparing the priority distribution recommended in EEMUA-191 and ISA-18.2,4 priority sections are selected to evaluate the alarm system of diesel hydrogenation unit.By combing and analyzing the key performance indexes of the alarm system given by EEMUA-191 and ISA-18.2,with consideration of the characteristics of the diesel hydrogenation unit,the key performance indexes of the alarm system for the diesel hydrogenation unit are given.According to the statistical analysis results of a diesel hydrogenation unit alarm system for a period of time,there are two weak aspects can be seen,the lack of effective methods to screen out the high risk alarm and difficulity of determining the optimization target of the alarm system.In view of the problem,the HAZOP analysis results of the diesel hydrogenation unit are applied to the analysis of the warning deviation result,combining with alarm rainbow chart,finally the warning alarm deviates from the consequences and limits the processing of the alarm can be obtained here.And through the risk map analysis,the severity of the alarm deviation and the operation pass rate are graded,the alarm risk grade is determined effectively,the high risk alarm is divided,and the optimization target is determined.For the high risk alarm of sifting,Aspen Plus is used to model the mechanism,the SRK equation is used in the physical method,and the steady state model of the diesel hydrogenation unit is constructed.The steady-state simulation results are converted to Dynamics through the Aspen built-in interface,and fluctuation of parameters involved in the high risk alarm and the influence factors of each process index are analyzed under different working conditions.For the diesel oil hydrogenation unit in the observation period,it is recommended to check the quantity of raw oil and the flow of new hydrogenand guarantee the treatment volume of raw oil to fluctuate within 400t/h-450t/h and the flow rate of new hydrogen less than 2300 kmol/h.