Guided radar provides accurate readings in crude oil processing |
After the crude oil arrives at the Vohburg site, the water must first be removed from the emulsion in an electrostatic desalinator before further processing. Sensors of the VEGAFLEX series now deliver precise values to ensure that the process separating the water and oil layers runs effectively.
Coping with fluctuating densities
From the point of view of interface measurement, there are a number of challenges here: The composition, and thus also the DK value and density, of the crude oil-water mixture changes depending on where the oil comes from. For example, the density can vary between 820 and 940 kg/m³. This means that the running time of the previously used measuring methods also varied.
A respected partner at two locations
VEGA, a tradition-rich company based in the Black Forest town of Schiltach, is a specialist in innovative measurement technology. Its main area of expertise is pressure and level instrumentation. Products that 1.), are easy to use and 2.), ensure maximum safety and reliability, are the company's trademark. VEGA has been present with numerous pressure and level sensors at the Bayernoil locations in Vohburg and Neustadt since 2013.Bayernoil and VEGA worked together to develop a new solution for the problem of measurement in the desalinator. Two years ago, a measuring instrument based on guided radar, a VEGAFLEX 86 with a reference section, was installed parallel to the existing displacement solution. The purpose was to measure the interface between oil and water as accurately as possible, especially when the DK values of the crude oil fluctuate, making it possible to operate the system even closer to its limits.
Defying vibrations and shocks
During the development of the VEGAFLEX Series 80 sensors at that time, the focus was not only on simple instrument selection and guided setup, but also on reliability and measurement certainty. The greatest advantage of the sensor: It delivers exact values regardless of media properties such as density or dielectric constant. Besides that, its distinguishing features are a robust mechanical design and a second process seal. It can be used at temperatures from -196 to +450 °C and pressures from -1 ... +400 bar.
In interface measurement with guided radar, the radar pulses are guided along a cable or rod probe and reflected by the product surface. The measuring probe of the TDR sensor ensures that the signal travels down to the product undisturbed. The series consists of four different instrument types, each of which is tailored to a particular application. VEGAFLEX 86 is often used for high temperatures and high pressure applications, e.g. in distillation columns or in crude oil processing. It has a ceramic insulation and graphite seal in the coupling that can withstand the penetration of steam at a maximum pressure of 400 bar and temperatures up to 450 °C. The spacers in the coaxial probe are also made of ceramic and mechanically stable enough to withstand the vibrations and shocks.
Simple setup and commissioning
In order to improve the sensitivity of the sensor, a special signal processing algorithm was implemented in the development phase. It is based on false signal suppression during setup and commissioning. The sensor subtracts this false signal suppression from the visible echo curve. The result is a straight echo line. The level echo is thus the only echo within the measuring range. Thanks to this method, media with very low reflectivity (dielectric constant) can be reliably detected.
Test run with a positive outcome
It quickly became apparent that the advantages of the self-compensating VEGAFLEX sensor had a positive effect on measurement accuracy, even with constantly changing crude oil quality. To be on the safe side, the displacement measurement was left in place so that the measured values could be compared with one another. The test run was consistently positive for 1.5 years, with no malfunctions during the entire period. After this successful test run, another desalinator with a VEGAFLEX 86 with reference section was put into operation last year. No abnormalities were found in the echo curve of this measurement either. In other words: At this measuring point as well, the changing composition of the crude oil doesn’t distract VEGAFLEX 86 as it tirelessly delivers reliable measured values.Export this article
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