Recently the Formosa Petrochemical Corporation in Taiwan tested KROHNE’s Pipeline Leak Detection System on a 144 km long jet fuel pipeline. We are pleased to confirm that a leak of just 3 mm in diameter was detected and localized within minutes.
In the early days pipeline leak detection was based on applying basic statistic, such as the sequential probability ratio test (SPRT), on the difference between in- and outlet flow. Although this method works reasonably well under stationary pipeline conditions, the sensitivity to detect small leaks decreases significantly when pipeline conditions become transient, e.g. during changes in flowrate or pressure. Unfortunately spontaneous leaks are most likely to arise during transient conditions due to the pressure changes in the pipeline.
To overcome these limitations a more sophisticated method, called Real Time Transient Modelling (RTTM), was developed. This method gives a far higher sensitivity during transient pipeline operations as it continuously calculates the behavior of the pipeline, based on flowrate, pressure and temperature at inlet and outlet. The model remains operational even if there is no flow at one side of the pipeline, e.g. during buffering in a gas pipeline.
In co-operation with the University of Applied Sciences in Gelsenkirchen – Germany, KROHNE enhanced this method by adding a unique pattern recognition algorithm. The benefit of this enhanced E-RTTM (Extended Real Time Transient Modelling) system is it reduces false alarms to virtually zero false alarms. With the E-RTTM model exactly calculating the conditions inside the pipeline, it forms the backbone of KROHNE’s PipePatrol Pipeline Management software.
Looking at legal aspects, for many years Germany has had the TRFL (Technical rules for pipelines) requirements in place. The TRFL states a.o. that pipelines that carry flammable or hazardous substances must be equipped with a leak detection system that remains sensitive under transient conditions. This is not just a theoretical exercise; a pipeline can only start operation after the system has been tested and approved by TüV.
In recent years other regions start following the German example and came up with legal requirements for pipeline leak detection. Amongst others, Taiwan recently implemented requirements that are somewhat similar to the German TRFL. In order to fulfill these requirements, the Formosa Petrochemical Corporation (FPCC) in Taiwan asked three vendors to provide a leak detection system on a 144 km long DN 300 (90 miles /12”) jet fuel pipeline for test purposes.
Leak testing was done in August 2018 and included leak test of 6 mm (1/4”) and 3 mm (1/8”). Even though the instrumentation on the pipeline was suboptimal for fast leak detection, KROHNE’s PipePatrol detected and localized both leaks within minutes during pumping conditions.