Flow Measurement of Ethylene
Polyethylene plastics are formed by polymerization of the hydrocarbon compound ethene (C2H4) commonly known as ethylene.
Soft polyethylene (LDPE), most commonly used as a packaging material, is produced in a high pressure process. During this process, ethene gas is compressed in a multiple stage compressor to a working pressure of approx. 2100 bar and sent into a tube reactor where the addition of an initiator starts the polymerization process. Exact information concerning the flow in each single line is paramount for effective process management.
Due to the high pressure levels involved, which can even peak up to 3.000 bar during the process, the conventionally used turbine flow meters showed a high failure rate and required frequent maintenance. Additional damage was created by the wax particles found in the delivery flows.
FLEXIM's non-intrusive clamp-on ultrasonic flow measurement technology, FLUXUS G, provided the ideal solution for this measuring challenge.
The transducers are simply clamped on to the pipe's outer surface, thus do not get into mechanical contact with the medium and are completely independent of the pressurization levels inside the pipe. The entrained particles do not cause any problems in terms of measurement accuracy and the system can be installed without any interruption of the production.
Thus, process interruptions due to failure of mechanical measuring equipment belong to the past.
Advantages
- Precise, non-intrusive gas flow measurement independent of pressurization levels
- Measurement is unaffected by vibrations, pressure surges and entrained particles
- No drift of measurement values caused by variations in the static pressure
- No need to stop operations for installation, inspection, servicing, or maintenance of the measuring system
