Mettler Toledo Tunable Diode Laser (TDL) Gas Analyzers

Reliable Gas Measurement with Low Maintenance Costs in In-situ and Extractive Applications

Safety is a matter requiring particular precision in gas measurement, especially in industrial processes, to protect people, the environment and living organisms, and this can only be achieved with the best equipment. Since a wide variety of measurement options are encountered in operational processes, the correct technology must be carefully selected for each measurement type. With recent technological advances in tunable diode lasers, this measurement method is increasingly gaining importance in enabling efficient and reliable measurement of different types of gases. Gas analysis using tunable diode laser (TDL) analyzers continues to spread rapidly in industrial processes. These analyzers are replacing alternative technologies such as paramagnetic, NDIR, zirconia analyzers and pellistor-based sensors, and are even being excluded from procurement evaluation processes. TDL analyzers measure gases using a spectroscopic method with technology based on Beer-Lambert's law. A laser beam tuned to a specific, very narrow frequency range passes through the gas, and analysis of the incoming light determines the amount of target gas in the sample. GPro® 500 Series TDL gas measurement analyzers are designed to provide high reliability across a wide range of applications.

Advantages Provided by Mettler Toledo GPro® 500 Series

In-situ or extractive: GPro® 500 can be mounted to reactors, pipelines or ventilation ducts, measuring the target gas in flow directly at any point where measurement is required. This operational flexibility provides more accurate and instantaneous measurements. GPro® 500 can also be used with an existing extraction system (gas conditioning unit). This eliminates the need for reconfiguration and removes the need for expensive extraction systems. In addition, its compact design makes it highly durable and long-lasting.

Transmitter and receiver in a single unit:

Many TDL technologies consist of two units (cross-stack): the transmitter (laser source) and the receiver (section analyzing the received laser beam). These two units must be positioned exactly opposite each other. Over time, effects such as material expansion can cause misalignment of these two units, resulting in measurement signal loss. GPro® 500 combines the transmitter and receiver in a single unit. A probe inserted into the gas flow contains a corner cube at its far end that redirects the laser beam from the transmitter back to the receiver probe. Thanks to this feature, GPro® 500 installation is significantly easier compared to cross-stack designs, and misalignment is not an issue.

High reliability:

The SpectraID® spectroscopy technology used in GPro® 500 is highly selective for the target gas and measurements are drift-free. GPro® 500 contains no moving parts that are subject to wear or breakage.

Heat and dust tolerance:

GPro® 500 can be used in many environments where heat and/or dust would make operation of other analyzer types impossible.

Lower maintenance:

Annual verification and periodic optical cleaning are the only maintenance required. Additionally, GPro® 500's low purge gas consumption reduces operating costs.

Broad gas range:

GPro® 500 series can measure many gases including O₂, CO, CO₂, H₂O, HCl, CH₄, NH₃ and H₂S. Process adaptations for every requirement: Adapting to the widest range of application and installation point options, GPro® 500 is available in various models with special probe designs that maintain purge gas requirements on the instrument side but eliminate purge gas requirements on the process side, as well as with a process connection suitable for measurement in small-diameter pipes such as DN50 and an extractive system adaptation for use with extraction systems, easily adapting with various process connections.

Examples of suitable processes include:

• Direct chlorination and oxychlorination process control. • VCM waste gas recovery. • FCC unit combustion optimization. • Electrostatic precipitator safety control. • Chlorine scrubber dryer outlet. • Ethylene oxide production. • Ammonia synthesis. • Carbon black process. Ahmet Aykut Yavuz Business Unit Manager Process Analytics Division Mettler Toledo Turkey