This white paper explains how TDL O₂ sensor can minimize inerting system maintenance & to integrate them into a DCS system for fully automated oxygen verification.
Maintaining low oxygen levels in chemical operations is often vital for safety reasons. Analyzers based around paramagnetic technology require frequent maintenance for extraction/conditioning systems to ensure measurement reliability, but by their nature have slow response times: an issue in safety-critical applications. In addition, such analyzers require a supply of zero and span gases for verification purposes.
Tunable diode laser oxygen sensors, such as the GPro® 500, operate in situ, directly in the pipe, vessel or tank, without the need for sampling and conditioning equipment. Unlike other designs of TDL where the two main parts (laser source and receiver) are positioned opposite each other on the pipe, duct or vessel, the GPro 500 is one unit with an attached probe. A corner cube at the probe's end directs the outgoing laser beam back through the probe to the receiver. This simplifies installation and eliminates the possibility of laser source and receiver becoming misaligned.
The GPro 500 has no moving parts, significantly reducing maintenance requirements, and a probe design with a blow-back filter allows maintenance to be reduced further. The blow-back filter, for use in processes with a high dust load, traps particles in the gas that could interfere with oxygen measurement. Periodically, air or an oxygen-free gas can be blown through the filter to clean it and restore measurement accuracy.
This ability allows convenient, remote sensor verification. Should oxygen measurements become out of range, initiating filter cleaning from the control room via the DCS can be used to exclude the GPro 500 as the source of the error.
Highlights of this white paper
- Issues with paramagnetic measurement technology
- Advantages of TDLs in inerting and blanketing operations
- Implementing TDL verification in a DCS