Compliance to standards in continuous emissions monitoring

The Challenge

A glass factory is required to continuously monitor emissions in compliance with the Operating Licence. The licence requires a reliable Continuous Emissions Monitoring Service (CEMS) installation for the measurement of Oxygen, NOx, Temperature and Opacity.

The exhaust gas temperature at glass manufacturing sites is particularly high due to the nature of the glassmaking process. Additionally, the acidic and corrosive particulates pose a specific challenge for most conventional monitoring systems.

Acoem was contracted to design, supply, install, commission, operate and maintain the CEMS on three stacks at the glass factory.

The Solution

The gas components, NO & NO2 are measured with open path Opsis DOAS UV analyser. The open path system means that an emitter mounted on one side of the stack shines a light beam onto a converging mirror in the receiver on the other side of the stack, from where the light signal is transmitted via optic fibre to the analyser. This means that the open path DOAS method is never in contact with the gas stream, thereby avoiding corrosion, temperature and particulate contamination problems that in site or extractive CEMS would have had to deal with.

Opacity and dust concentration is continuously measured with a double pass compliance particulate monitor in accordance with the requirements of USEPA PS-8. The dust monitor is protected by fail safe shutters and a high temperature accessory kit to reduce the effects of the high exhaust gas temperature.

The Outcome

• The Acoem open path DOAS CEMS design greatly reduced the preventative and reactive maintenance requirement that a conventional CEMS would have required.
• The reduced maintenance requirement also means that the CEMS reliably provides >98% valid data yield on a continuous basis.
• The NATA accredited process of operation, maintenance and calibration of this type of CEMS by Acoem gives greater robustness, quality and efficiency to the management of the process.