To comply with new air pollution regulations, SGL Carbon—a global leader in synthetic graphite—needed continuous monitoring of hourly dust concentrations and flows at its Passy, France plant. Following tests of two systems from different suppliers, SGL chose ENVEA’s particulate CEMS analysers for their precision, reliability, and low maintenance.
Located in the Arve Valley in the French Alps, an area particularly sensitive to air pollution due to its topography, SGL Carbon’s Passy site needs to adhere to strict emission limits imposed by atmosphere protection plans from the local government.
A 2018 mandate required continuous monitoring of hourly dust concentrations and flows for approximately twenty stacks, which the plant’s previous triboelectric probes were not equipped to do. Pollution levels are also monitored between November and March, with the plant being forced to partially shut down if limits are exceeded.
SGL Carbon recognised the need to invest in advanced emission measurement and reduction technologies to meet regulatory standards—but compliance alone wasn’t enough. They aimed to go further by implementing real-time dust emission monitoring to enhance preventive maintenance and downtime strategies, particularly during pollution alert periods.
SGL Carbon conducted a year-long evaluation of two different technologies for continuous emissions measurement. They equipped five stacks with the QAL 991 electrodynamic analysers and six with optical analysers from another supplier.
“Following the test period, we chose the particulate CEMS analysers due to their superior precision, reliability, and minimal maintenance needs. Unlike systems with mechanical components, the electrodynamic technology eliminates the need for fans, reducing maintenance complexity. This is especially valuable given that several measurement points are accessible only via an aerial platform. Finally, ENVEA’s exceptional technical support was a significant factor in our decision.”
Pierre Praicheux, Site Manager, and Sylvain Collet, HSE Manager, SGL Carbon Passy
In 2021, SGL Carbon experienced two pollution alert episodes in the Arve Valley: a level one alert from January 12-13 and a level two alert from February 24-28, which led to the shutdown of three stacks. They were able to provide detailed hourly data on avoided emissions––approximately 5 grams of particulates per stack per day––and get the stacks back up and running quickly.
SGL now deploys hourly reporting of avoided emissions during pollution alerts, minimising the risk of partial plant shutdowns while strengthening environmental protection.
Overall, SGL Carbon’s investment in ENVEA solutions has facilitated compliance with stringent environmental standards, optimised operational performance, and reinforced the company’s commitment to environmental responsibility.