High Temperature Flow Measurement for Coker Control

Like most coker plants in the world, the coker of a large refinery in the southern part of Germany also works according to the Foster Wheeler patented delayed coking method.

The residue left over from the crude oil distillation is led through a tube furnace and heated up to temperatures of 950 °F. Due to the short time the residue stays in the oven, the coke formation takes place in a “delayed” manner during devolatilisation in downstream coke drums.

Feeding of both coker furnaces at the refinery takes place via four feed lines. Optimum mass distribution within the furnace zones is crucial for efficient process control and for the service life of the furnace.
The measuring orifices plates / differential pressure meters that were permanently installed for flow measurement were subject to huge maintenance costs due to the challenging, highly viscous medium with its constant load of coke particles. The thin impulse lines of the DP meters were constantly becoming blocked and had to be rinsed out regularly. Furthermore, this also led to coke deposits in front of the orifice plate.

For this reason, process engineers looked for a modern, maintenance-free alternative. The solution was FLEXIM's non-invasive flow measurement with FLUXUS and the WaveInjector.

The clamp-on ultrasonic transducers which are attached to the outside of the pipe are not subjected to wear and tear by the medium flowing inside the pipe. In addition, the non-invasive, acoustic method is characterized by considerably higher measuring dynamics so that reliable measured values are even achieved during startup and shutdown, thereby making automatic control possible.

By emplyoing the patented WaveInjector mounting fixture, the ultrasonic transducers are thermically separated from the pipe. Thus, even extreme pipe wall temperatures up to 1100 °F are not a challenge for FLUXUS.