ACHEMA: Liquid Nitrogen Cools Chemical Processes

ACHEMA 2000: Liquid Nitrogen Cools Chemical Processes

"Pharmaceutical companies are not telling us exactly what they are doing, but a lot of them are buying liquid nitrogen systems to cool chemical processes," said Christian Trgo of Linde Technische Gase GmbH (Koln, Germany) at the ACHEMA show in Frankfurt, Germany. "They're looking at pilot-sized plants that can operate at around -80°C to -100°C."


Christian Trgo explaining Linde's nitrogen-cooled chemical process at ACHEMA.

Not surprisingly, Linde has the answer: a liquid nitrogen cooling system capable of reaching –130°C and lower. There are several ways Linde could have built the unit. They could have fed liquid nitrogen (1) directly into the reaction mass, (2) directed it through a built-in cooling coil or jacket, (3) or used it to chill a heat transfer medium which then cools the reactor.

Linde recommends the third method, since it allows users to also use the heat transfer fluid to heat the react. The configuration provides several advantages:

  • Flexibility. Users can run several steps in a single reactor merely by changing temperature. Easily modified temperature profile.

  • Precision. Rapid temperature changes provide effective control over process sequences.

  • Speed. Short cooling and heating times.

  • Reliability. Precise temperature selection improves process reliability.

  • Quality. Comprehensive recording of process parameters supports high product quality.

  • Economics. Nitrogen used for cooling feeds into the inert gas network.

    According to Linde, the system supports temperatures of –130°C to +130°C with a maximum pressure in the heat transfer medium circuit of 10 bar. The unit's heating and cooling capacity is 25 kW.

    The unit uses an expansion vessel to equalize temperature-related changes in volume, yet takes up relatively little space. It comes with a programmable logic controller linked by bus with the master process control system.

    Linde provides all services for the unit, from concept definition through construction, commissioning, and ongoing nitrogen supply.

    For more information: Christian Trgo, Linde Technische Gase GmbH, Vertriebszentrum Koln Anwendungstechnik, Gruner Weg 6-12, 50999 Koln, Germany. Phone: +49-22-36-3908-83. Fax: +49-22-36-3908-88.

    By Alan S. Brown