Cooling rubber waste with liquid nitrogen

ERJ staff report (RD)

Drunen, the Netherlands - Dutch company Celsius has developed a new screw heat exchanger, which conveys rubber waste, while simultaneously cooling it with liquid nitrogen (-196 deg C), the company announced recently.

Developed for the Germany-based rubber recycling, reduction and grinding company Gothic, the screw heat exchanger, with cryogenic application, will be used for the recycling of rubber tyres, the company said.

Celsius explained that the addition of liquid nitrogen causes the rubber to go below the glass transition temperature and become hard and brittle. This makes it suitable to be ground in a pin mill into fine powder (cryogenic grinding). This powder is suitable to be re-used in new rubber and synthetic products, the company added.

The screw heat exchanger conveys the frozen rubber to the grinder over a distance of 2 500 mm with a capacity of 1.6 m³/hour, the company explained, adding that during the conveyance the liquid nitrogen is injected into the product at 4 points. “The paddles of the screw mix the rubber well with the nitrogen,” Celsius said. “The conveyor has a jacketed tube, which is vacuum for better insulation,” the company concluded.

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Press release from Celsius