Measurement solution for carbon fibre process and emission monitoring - Monitoring and Testing

What needs to be measured?

The carbonisation processes produces off- gases as the PAN fibres are heated. The most critical off gas is Hydrogen Cyanide (HCN), along with Ammonia (NH3), Formaldehyde (HCHO), Methanol (CH3OH) and other organic compounds in low levels. The carbonisation process is varied by changes to the speed of passing the filament through the ovens, the oven temperature, the oxygen content and other process adjustments. This all leads to variations in the off-gas concentrations.

Measurement of the gases in the process ovens is required to ensure HCN levels are at safe levels, as HCN could potentially reach a LEV level. Knowledge of the gas mix in the ovens can help the oven production to be increased, increasing fibre production.

All the oven gases pass through abatement systems before passing to atmosphere. This can include catalytic crackers and incineration. The major product of the destruction of HCN is NOx (NO, NO2 and N2O). Emissions limits are imposed on the total NOx output, as well as insuring HCN emission levels are below expected concentrations.

atmosFTIR Solution

The design of atmosFIR FTIR gas analyser is particularly well suited to the requirements of carbon fibre plants. With built in sampling system, it is a self-contained unit, allowing measurement use on emissions vents in compliance with legislative requirements.

On multi-emission points from the carbon ovens, it is ideal as it is a transportable unit, able to be either fixed or moved to sampling locations. atmosFIR can be removed from its main location sampling emissions vents and moved on-plant. Here it is deployed as a process improvement tool, being able to measure the gas composition deep inside the carbon ovens.

Full Gas Matrix

The FTIR gas analyser is a powerful tool, with its full spectrum capability allowing for measurement of all required gases in carbon fibre production.

Simplicity of Measurement

The use and set-up of FTIR analysers has in the past been a task requiring trained users. atmosFIR is provided with a pre-loaded Application Method for every process, such as carbon fibre production. This application method is often built during the system design process, with real on-site data collected on a temporary installation. This means that the final system meets the exact requirements of the application and the user can achieve accurate data from the moment the system is commissioned.

Multi-point CEM Arrangement

Each carbon fibre production line is made up of a number of ovens. Each oven has its own abatement system which requires monitoring for emissions. The atmosFIR has been deployed in systems allowing the measurement of up to 10 separate sample points on the one instrument.

The sampling system is completed heated, up to 180˚C. Each sample point has a heated probe with integrated filter. Heated sample lines of length up to 50m are arranged into a heated valve manifold. This manifold allows automatic or manual switching of any of the streams. The complete heated sampling system is controlled and managed from a dedicated panel, including all relevant current protection and safety considerations.

On-line Software

PAS-Pro provides an easy-to-use software interface for the site engineer. At the heart of the software are the advanced chemometric routines used to model the gas matrix. These are supported and uploaded by Protea’s application support staff.

The interface allows simple control of purge, span and calibration of the system. On-line measurements are reported with analysis accuracy indications that are in-line with the requirements of FTIR analysers deployed for emissions monitoring in the UK.


PAS-Pro software allows for the programming of a sequence for the multi-stream measurements. This can be a standard fixed period per stream, say 2 hours. Or a sequence of shorter or longer periods for different streams can be programmed.

Each measurement stream has a unique name or tag. The data for each stream is saved to a separate log file, for ease of data analysis. With data outputted over OPC Server or Modbus connections, separate output tags are available for each stream.

Protea Support

Protea has a dedicated team of application specialist based in the UK to help with all aspects of deployment of FTIR analysers in monitoring scenarios.

Protea FTIR analysers can be provided with always-on 3G connection, allowing data to be fed to Protea and advice and support to be fed back. Live systems in the field can be updated remotely with software upgrades or new analytical models.

From standard compliance monitoring, to specialist process measurements, we can supply the equipment and application knowledge to make the job of making measurements as straight forward as possible.