2VALVE PASSINGRefers to flow through a valve which is set in the “off” state (closed).FACTORSIMPACTSeat alignmentInsufficient actuator travelPoor maintenanceCorrosive and/or erosive process mediaValve seat is prevented from fully closed due to dirt/rust.SafetyEnvironmentProductionAsset IntegrityAmserve Engineering Sdn. Bhd.
3NON-INTRUSIVE ACOUSTIC VALVE INSPECTION (NAVI) Technology from FranceUsed widely in Nuclear Power Plant to detect passing valves and steam trapsExperience more than 20 yearsEurope, North America, AfricaNo permanent installation requiredInspection is fast and reliableEstimation of leak rate based on actual data collectedAmserve Engineering Sdn. Bhd.
4WORKING PRINCIPLESBased on passive measurement of ultrasonic acoustic emission. These sounds are generated by the flow of fluids through leaking valves under pressure.The NAVI hardware takes the sound measurement signals, processes and displays them as a signature most suitable to identify and quantify the leaks.Test requirementsValve to be tested must be in closed positionThere is a differential pressure across the valve, at least 1 barg.Amserve Engineering Sdn. Bhd.
5THEORY OF APPLICATIONAcoustic emission is a structure borne noise and it is generated by the process medium flow. NAVI detects leak noise caused by turbulent flow, which is measured in decibels (dB).If a valve is in open position, there will be laminar flow that generates little or no noise.A tight valve makes a very little or no noise.A passing valve creates turbulent flow and acoustic noise. The AE is transmitted into the valve body.Amserve Engineering Sdn. Bhd.
6INSPECTION TOOL Hardware Panasonic Toughbook Model CF-19/Getac Touch-sensitive screenAcquisition card up to 2400 kHzIntrinsically safe (Zone II)Software & AccessoriesDigital NAVI AnalyzerContains database, current and previous.Piezoelectric accelerometer and heat sink compoundSensor Cable/SensorHeat Sink CompoundAmserve Engineering Sdn. Bhd.
7AE MEASUREMENT2. Place sensor on the upstream piping, take background noise.1. Place sensor on the valve body, take pressure noise.3. Place sensor on the downstream piping, take background noise.Amserve Engineering Sdn. Bhd.
9ANALYSIS Differential Signature VALVE PASSING Analysis Background Noise (Up)Pressure Noise (Body)Background Noise (Dwn)Differential SignatureVALVE PASSINGAnalysisIf Pressure Noise is greater than Background Noise, then the valve leaks.If Pressure Noise is equal to Background Noise, then the valve is tight.Amserve Engineering Sdn. Bhd.
10ANALYSIS Differential Signature VALVE TIGHT Analysis Background Noise (Up)Pressure Noise (Body)Background Noise (Dwn)Differential SignatureVALVE TIGHTAnalysisIf Pressure Noise is greater than Background Noise, then the valve leaks.If Pressure Noise is equal to Background Noise, then the valve is tight.Amserve Engineering Sdn. Bhd.
11Continue Monitoring 6-Monthly Estimation of Leak Rate ANALYSISPASSINGNO PASSINGContinue Monitoring 6-MonthlySmallMediumLargeLarge Leak – 24 dB and aboveValve recommended to be replacedSmall Leak – 1 to 9 dBContinue Monitoring 6-MonthlyMedium Leak – 10 to 23 dBValve Need RepairingEstimation of Leak RateTolerable Leak Threshold for Various Type of Valves (Shell IMP 3.02 Table 1)Amserve Engineering Sdn. Bhd.
12CASE STUDY 1: LAUNCHER PRESSURE BUILT UP RECTIFICATION (EXTRACT FROM CLIENT REPORT) JANUARY 2013Amserve Engineering Sdn. Bhd.
13CASE STUDY 1: LAUNCHER PRESSURE BUILT UP RECTIFICATION Trunkline RY (Launcher L-2900) and Trunkline RZ (Launcher L-2910) found high pressure build-up in launcher barrel (up to 80 barg/day) after pigging activities.After lubrication & sealing, RY launcher pressure build up controlled at 1 – 2 barg/day. RZ launcher pressure build up higher at 3 – 5 barg/day.Further rectifications was requested to verify root cause.Action Items:Mobilized Amserve to conduct non-intrusive acoustic valve inspection on MOVs to determine leakage rate; and check for any passing from kicker line and vent line.Mob valve maintenance vendor to conduct MOVs alignment, perform greasing and sealing.Amserve to verify passing valves and final leakage rates.Amserve Engineering Sdn. Bhd.
14CASE STUDY 1: LAUNCHER PRESSURE BUILT UP RECTIFICATION MOV290X2MOV290X1Non-Intrusive Acoustic Valve Leak Inspection was performed onMOV290X1, MOV290X2Kicker Valves (VX-2901, VX-2902)Equalizing Line Valves (VX-2904, VX2905)Vent Valves (VX-6395, VX6396)Amserve Engineering Sdn. Bhd.
15CASE STUDY 1: LAUNCHER PRESSURE BUILT UP RECTIFICATION NAVI Result for RY (L-2900)No serious passing detected from kicker valves, equalizing line valves and vent valves. Pressure build up not likely contributed from these valves.MOV290X2 (riser side/tee) passing rate still within allowable limit, but the high dB ratio indicate ACTUAL passing rate could be higher than the estimation.MOV290X1 (launcher side) passing rate exceeded allowable limit, but lower than MOV290X2.CONCLUSION: Build up of pressure in launcher is likely from MOV290X1 and MOV290X2.Amserve Engineering Sdn. Bhd.
16CASE STUDY 1: LAUNCHER PRESSURE BUILT UP RECTIFICATION TOLERABLE LEAK THRESHOLD (SHELL IMP 3.02 TABLE 1)ItemTypes of ValvesTolerable Leak ThresholdWarning Limit(% TLT)Gas service (kg/s)Oil service (kg/s)1Riser ESD Valves (1)0.1752Launcher/Receiver 1st MOV (at barrel) (1)0.01503Launcher/Receiver 2nd MOV (at barrel) (1)4Process ESD Valves (SDV, ROV) (2)5Depressurization or Blow-down valves (3)0.036Motorized Isolation Valves (MOV) (4)0.01, 0.150, 757Process Control Valves and FCV (5)8Mechanical Isolation Valves (6)9Integral DBB Valves (7)10Non Return or Check Valves (8)0.3Note:Based on consequence of 2 mm pinhole leak with 5 m jet fire as per Riser Tolerable Leak Rate Study Rev.0 Mar 2008.Rate of 0.1 kg/s is based on the worst case consequence similar to Riser ESD valves with blow-down duration of 15 min or more and 0.3 kg/s for case with depressurization less than 10 min from maximum operating pressure to 7 barg.Rate is based on flaring limit of 0.1 MMscfd of one valve or 2.0 MMscfd for total valves of the platform.Rate is based on consequence cases similar to Pig-trap valve, i.e. last barrier 0.01 kg/s and otherwise 0.1 kg/s.Only for FCV and those process control valves that serve also as shutdown valves (no other Process ESD valves) and rate shall follow the Process ESD valves.Rate is based on consequence cases similar to Motorized isolation valves.Rate is based on consequence case similar to last barrier of MOV, i.e kg/sRate is based on the consequence of blow-down valves.Amserve Engineering Sdn. Bhd.
17CASE STUDY 1: LAUNCHER PRESSURE BUILT UP RECTIFICATION Result after cleaning and re-sealingPressure built up contained to 0 barg after 2 days of monitoring (2 barg after 4 days).NAVI was conducted again, result shows MOV290X2 is still passing and confirmed by continuous passing of gas at body vent.MOV290X1 shows minimal passing, and greatly reduced passing from body vent. Most of riser pressure is being contained by MOV290X1.MOV290X2 shall be replaced as soon as possible.MOV290X1 shall also be considered for replacement. Without sealant, leakage will become worst.Amserve Engineering Sdn. Bhd.
18CASE STUDY 3: TO IDENTIFY PASSING CHECK VALVES FOR P-6250 JAN 2013Amserve Engineering Sdn. Bhd.
19CASE STUDY 2: CHECK VALVES System Area: M1 P-6250Situation: Pump suction check valves and pump discharge check valves were suspected passing, however could not be identified.Action Items:Amserve to carry out NAVI. Pump was let run until reach consistent desired discharge pressure, then stopped to create backflow.Result:Passing valves were identified. Leak severity ranged from small to medium leak, however estimated leakage rates are still within tolerable leak threshold for check valves (0.3 kg/s).Amserve Engineering Sdn. Bhd.
20CASE STUDY 3: VALVE PASSING VERIFICATION FOR A NEWLY INSTALLED VALVE AT TML PLATFORM MAY 2012Amserve Engineering Sdn. Bhd.
21CASE STUDY 3: TML NEWLY INSTALLED VALVE System Area: TML’s BR-A Pipeline Isolation ValveSituation: During recent shutdown, a new valve was installed to replace previously reported passing valve. During pressurization, pressure build-up was observed at the downstream. Client requested for verification and estimation of leak rate, as not to exceed the standard allowable leak rate* (1 kg/min for natural gas).Action Items:Amserve was notified on the situation and was mobilized to site.Result:It is found that the valve passing and the estimated leak rate is still within the allowable leak rate. OIM and maintenance team were notified on our findings.Amserve Engineering Sdn. Bhd.