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Impulse Line Blocking Diagnosis

Impulse Line Blocking Diagnosis

Introduction

Impulse Line Blocking Diagnosis in DP Transmitters

Figure1. Connected to impulse lines
Figure 1 Connected to
impulse lines

Differential pressure (DP) flowmeters composed of an orifice plate, a DP transmitter, and other components are widely used in many applications because they are reliable and require no wet calibration. The simple design of orifice plates and modern DP transmitters make them extremely reliable. However, the impulse lines which transmit process pressure to the DP transmitter are vulnerable to blockages caused by fluid condensation, freezing, or corrosion. Impulse line blocking is a problem that must be addressed to ensure efficient operation and maintenance.

Yokogawa's EJX series DP transmitter is equipped with a silicon resonant sensor that can rapidly detect both static pressure and differential pressure. These features enable the development of a diagnostic technique which detects fluctuations in static and differential pressures. By using a digital communications network such as fieldbus, operators can determine whether an impulse line at a specific installation site has been blocked. Such information can significantly reduce maintenance workload and cost.

Expected Benefits

  • Informs operators/maintenance engineers that a blockage is forming in an impulse line before the process is disrupted.
  • Predicts when the impulse line will be blocked and suggests a corrective action, based on blockage thresholds.
  • Blockage thresholds are determined based on blocking substance, flowrate variation, and the time required for taking corrective action.

Impulse-line-blocking Diagnostic Technique

(1) Fluctuation of differential, static pressures

Table 1. Fluctuating component values in impulse lines

Table 1 Fluctuating component values in impulse lines

Fluctuating components of differential, static pressures generally decrease when an impulse line is blocked.

Fluctuating components are calculated as the square summation of the difference of differential and static pressures that are sampled at very short time intervals. The amplitudes of fluctuating components are derived from the root of the square summation. Since these components are affected by flowrate changes, they are provided as fluctuation components through flowrate compensation.

Table1 shows the value of the fluctuating components when blocking occurs on the Hi-side, Lo-side, and both sides. The values for when no blocking occurs are also shown. When both sides of impulse lines are blocked, all fluctuating components decrease. When one side of an impulse line is blocked, the corresponding fluctuating component decreases. In this case the fluctuating component of differential pressure is larger than when no blockage occurs.

(2) Blocking diagnosis using water flow test rig

Figure 2. Blocking factor F with H and L side blocking

Figure 2 Blocking factor F with H and L side blocking

Blocking factor F is determined as the correlation function between the amplitudes of fluctuating components. It approaches +1 for high side blocking and -1 for low side blocking. Figure2 shows the Blocking factor F for each blocking type.

Conclusion

Operators must receive diagnostic information before a line block leads to a malfunction. Yokogawa provides predictive diagnostics based on trend analysis of the blocking factor, which improves maintenance efficiency and reduces maintenance costs.

Note:

This diagnostic function is currently available for low viscous liquids only.

Gerelateerde Industrieën

  • Olie & gas

    Yokogawa heeft diepgaande ervaring in elk deel van de olie- en gasindustrie. Van offshore- en onshore-installaties tot pijpleidingen, terminals en diepwateractiviteiten. Wij leveren oplossingen die de veiligheid verhogen, een nauwkeurige en betrouwbare werking garanderen en de efficiëntie van de installatie verhogen.

  • Chemicals

    Chemical products are indispensable to modern life and industry. Chemical plants, where these products are manufactured, are required to maintain stable operations 24 hours a day, 365 days a year while achieving high levels of safety, productivity, and sustainability. Leveraging more than 100 years of expertise in measurement and control, together with digital technologies such as AI, Yokogawa helps chemical industry customers achieve sustainable growth. Together with Yokogawa, shape the future of your manufacturing operations.

  • Refining

    In de steeds veranderende markt worden raffinaderijen niet alleen gezien als installaties voor de verwerking van ruwe olie, maar moeten ze ook rendement opleveren. Tegelijkertijd is men zich bewust van de noodzaak van veiligheid in dergelijke installaties. Een totale productieoplossing die planning, beheer en controle omvat, is vereist om de lange termijn doelstellingen inzake rentabiliteit, efficiëntie en milieubescherming te bereiken. Met jarenlange expertise op het gebied van automatisering kan Yokogawa u betaalbare totaaloplossingen bieden voor efficiëntere productie en een schonere wereld.

  • Offshore (FPSO FLNG & FSRU)

    Offshore exploratie en productie vereist maximale uptime onder zware omstandigheden. Bemande en onbemande installaties hebben behoefte aan betrouwbare geïntegreerde controle- en veiligheidssystemen (ICSS) met geavanceerde mogelijkheden voor bewaking op afstand. Yokogawa beschikt over ultramoderne technologie en uitgebreide ervaring in de uitvoering van offshore projecten van elke omvang en complexiteit van de automatisering.

  • Upstream olie & gas

    De upstream-industrie omvat offshore- en onshore-activiteiten, waaronder automatisering van boorputten, raffinage, voltooiing en scheiding om ondergronds of onder water ruwe olie en aardgas te winnen en te bewerken.

    Wanneer aardolie naar de oppervlakte wordt gebracht, moet het worden gescheiden voordat het wordt vervoerd. Primaire en secundaire scheidingsfasen verdelen gewoonlijk de gasstroom, waterstroom en oliestroom in een driefasen scheiding. Voor het vervoer van gas is een pijpleiding nodig en kan een raffinageproces in de upstream fase voorafgaand aan het vervoer plaatsvinden. Vloeistoffen kunnen via tanks of pijpleidingen voor verwerking worden verzonden, waarbij nauwkeurige niveaumetingen vereist zijn.

Gerelateerde producten & oplossingen

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  • EJX210A

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  • EJX630A

    In-Line Mount High Performance Gauge Pressure Transmitter based on the EJX-A Series.

  • EJX910A

    This transmitter precisely measures differential pressure, static pressure, and process temperature; then uses these values in a high-performance on-board flow computer to deliver fully compensated Mass Flow.

  • EJX930A

    Designed specifically for high static pressure applications, this transmitter precisely measures differential pressure, static pressure, and process temperature; then uses these values in a high-performance on-board flow computer to deliver fully compensated Mass Flow.

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