HAZOP-2危险与可操作性

1、Introduction to Hazardous Evaluation Techniques Guidelines for Hazardous Evaluation Procedures (1992 by AIChE). Second Edition with Worked Examples. Center for Chemical Process Safety (CCPS). American Institute of Chemical Engineers (AIChE).Hazard Evaluation Techniques1960 - 20011960 - 20011965 - 20

2、011970 - 20011972 - 19741974 - 2001SafetyCheck ListsRelativePHAWhat ifHAZOPReviewRankingWalkHistoricalICI MondPreliminaryBrainstormingHazardsThroughListsIndexHazardOperabilityInspectionAnalysisAnalysisYes / NoDow FEIHazardous MtlsLine by LineHazardous OpnsDeviationAnalysisThis presentation only cons

3、iders the HAZOP technique.HAZOP HAZOP was developed by Lawley (1974) of ICI. Based on early account by Elliott & Owen (1968). Hazop studies are carried out by an experienced, multidisciplanary team. Review all physical aspects of a process (lines, equipment, instrumentation) to discover potentia

4、l hazards.Basis for HAZOP The basis for a HAZOP is a critical examination of information found in a word model. It includes a flowsheet, a plant layout, equipment specification or a P&ID, (Piping and Instrument Drawing).Hazop Includes1Intention2Deviation3Causes4Consequences (a) hazards (b) opera

5、ting difficulties5Safeguards6Recommendations / ActionsHazop Guide WordsNO or NOTNegation of intentionNo Flow of AMOREQuantitative increaseFlow of A greater than design flowLESSQuantitative decreaseFlow of A less than design flowAS WELL ASQuantitative increaseTransfer of some component additional to

6、APART OFQuantitative decreaseFailure to transfer all components of AREVERSELogical opposite of intentionFlow of A in direction opposite to design directionOTHER THANComplete substitutionTransfer of some material other than AMore recent computerization techniques use a Standard Set Of Generic Deviati

7、onsFor Specific Section Types. See Devns tab for examples.Common HAZOP Analysis Process ParametersFlowTimeFrequencyMixingPressureCompositionViscosityAdditionTemperaturepHVoltageSeparationLevelSpeedToxicityReactionPrepare for the ReviewAttitudePreparationMeeting LeadershipHAZOPReview By Documentation

8、 Follow-upTeamKnowledgeInfo for studyExperienceTeams HAZOPP&Ids, LayoutExperienceTableDeviationCausesConsequences SafeguardsActionHazopFlowSheetSelect a processsection or operating stepExplain design Repeat for allintentionprocess sectionsSelect a processRepeat for allvariable or taskprocess var

9、iablesApply guide wordRepeat for allto process variableguide wordsExamineDevelop actionConsequencesitemsassociated with deviation List possible Assess acceptabilitycauses ofof risk based on deviationconsequencesIdentify existingsafeguards toprevent deviationHazop PitfallsPoor understanding by manage

10、ment of the HAZOP procedureAn Ethylene plant has 100 P&IDs, 625 equipt items. 625itemsConsider 5 variables, Pressure, Temperature, FlowComposition and Function.5variablesConsider 6 Guidewords, None, More of, Less ofPart of, More than and Other than.6guide wordsQuestions to be answered =18750ques

11、tionsConsider 5 minutes per question =5min./questionTime for ethylene plant HAZOP study =93750minutes4 hour, 240 minutes sessions per day =250minutes/dayNo. working of days =375daysDays per week =5days/weekNo. of weeks to complete HAZOP for plant =75weeksOther Pitfalls Inexperienced HAZOP team. Inad

12、equately trained or in-experienced leader.Common Hazop Mistakes Failing to establish a safe environment for team members. Consequences of events not carried to conclusion. Taking unwarranted credit for safeguards. Too little credit given for safeguards.Hazop Mistakes Contd Failure to make recommenda

13、tions as specific as possible. Poor record keeping of HAZOPS. Failure to HAZOP start-up and shut-down procedures. P&IDs not up-dated or poorly constructed.Hazop Mistakes Contd A HAZOP is performed in lieu of properly executed design reviews. Wrong technique for system being reviewed (See spreads

14、heet titled Fig 5.3).HAZOP ExampleTo Compressor InletTeams tend to quickly identify alarms, shut-downsand controls, and claim them for safeguards.An alarm not tested may not work when called uponInlet Lineto do so.Nuisance alarms are frequently bypassed and arenot effective as safeguards.Often opera

15、tors are not monitoring control panel.Valve in manualAutomatic control routines are often set in manualmode. FV 1 LAHLIC 1Standard Set of DeviationsID No.DeviationColumnVesselLineExchangerPumpCompressor1High FlowX2High LevelXX3High InterfaceX4High PressureXXXX5High TemperatureXXXX6High Concentration

16、XXX7Low / No FlowXX8Low LevelXX9Low InterfaceX10Low PressureXXXX11Low TemperatureXXXX12Low ConcentrationXXX13Reverse / Misdirected FlowXX14Tube LeakX15Tube RuptureX16LeakXXXXXX17RuptureXXXXXXTypical Hazop WorksheetCompany NovaRevision0Date02-Jun-97LocationCorunnaDwg No.Cor -123-4567Page1LeaderRAHPro

17、c DesJBResearchOp TechScribeGFRInstrtsGHElectricalHHOtherProdnPMMechFDSafetyMNOtherNode No.1DescribeTransfer Ethane from Deethanizer to C2 KO PotIntentionThe intent is to transfer 150,000 lb/hr of C2/C2= mix at 300 psig and at -30 F for the startup period.Guide WrdHighParamFlowDevn High FlowPossible

18、 Causes1FV-1 Wide open2Line break.3Consequences1High level in KO pot with liquid carry-over to compressor with serious damage to rotor. Potential hydrocarbons release.2Potential hydrocarbon release.3Safeguards1High level alarm LAH-12High - High level alarm HHLA - 1 shutdown.3Vessel inspection yearly

19、.Recommendation / ActionsRespibByDate1Consider limiting flow orifice, auto SD trip on High-High level, smart check valve.1JB01-Jan-992Determine extent of typical hydrocarbon release.2PM15-Jan-993Set-up vessel inspection yearly.3FD30-Jan-99Check List Example1 Changes In QuantityaHigh Flow1 Pump racin

20、g, delivery vessel pressure lost, suction pressurized, scale dislodged, leak in heat exchangerLoss of automatic controlbLow Flow2 Pump failure, scaling of delivery, presence of foreign body, poor suction condition, cavitation, leak in heat exchanger, drain leak, valve jammedOperator errorcNo Flow3 P

21、ump failure, delivery vessel overpressurized, gas blockage, presence of foreign body, scale, sediment, suction vessel empty.Failure of joint, pipe, valve, trap, bursting disc, relief valve.dReverse Flow4 Pump failure, pump reversed, delivery vessel over pressurized, poor isolation, gas locking, surg

22、ing, back siphoning.Check List Contd2 Changes in physical conditionaHigh or Low pressure1 Boiling, cavitation, freezing, chemical breakdown, flashing, condensation, sedimentation, scaling, foaming, gas release, priming, exploding, imploding. Changes in viscosity, density. External Fire, Weather conditions, Hammer.bHigh or Low Temperature2 s