Triadis Services in Étampes tests catalytic unit to neutralize nitrous oxide cylinders, 99.9% efficiency
A Séché Environnement subsidiary in Essonne runs a three-month test of a unit that decomposes N2O from partly full cylinders, avoiding incinerator explosions and venting.
Triadis Services, a hazardous-waste sorting and consolidation platform in Étampes (Essonne) and a subsidiary of Séché Environnement, has started neutralizing nitrous oxide cylinders that still contain gas, actu.fr reports. Early this year the company bought a catalytic decomposition unit from a Swedish firm. The unit has been running since 1 October as a three-month industrial test supervised by the Essonne prefecture. actu.fr
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Triadis collects about 42,000 nitrous oxide cylinders a year. According to site director David André, the cylinders come from waste collection centres, municipal technical centres and municipal police. The company had been looking for a local way to treat and recover these abandoned cylinders.
Why partly full cylinders are a problem
André said that cylinders are sometimes thrown out with household waste. In an incinerator, heat can make them explode, which can damage the installations, injure staff and force the furnaces to stop for hours or even days.
Nitrous oxide is also a strong greenhouse gas. André cited a warming potential about 273 times that of CO₂ over 100 years and said that venting non-empty cylinders into the air is not an option. Previously, cylinders collected at Étampes were repackaged and sent to the Lyon region for treatment, he said. actu.fr
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How the unit works
The gas is heated to 300 °C and passed over catalysts that decompose N2O into nitrogen and oxygen, which are then released. André stated that the machine's efficiency is 99.9%. Once a cylinder is empty, its brass valve is separated from the steel body, and the plastic parts are recycled into packaging or pipes.
The unit can process 14,000 non-empty cylinders a year. Non-empty cylinders from current clients amount to about 6,000 a year, so there is spare capacity for local authorities that are not yet clients. Triadis already handles cylinders from Paris, Hauts-de-Seine, Essonne, Loiret, Eure-et-Loir, half of Yvelines and Seine-et-Marne. Étampes is one of four sites in France with this kind of solution.
The company positions the unit as a local alternative to incineration that can shorten the time needed to clear stocks of cylinders picked up on streets. It is not the cheapest option, which may be a constraint for municipalities with tight budgets. actu.fr
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