Low-temperature cooling system type TG-RD for glass reaction vessels Temperature range from +100°C to -180°C measured at the internal temperature sensor

Cryogenic cooling for reaction vessels down to -180°C

In order to meet the requirements for fast cooling speeds and low temperatures, it is sometimes possible to switch from conventional thermostat cooling to liquid gas cooling. KGW-ISOTHERM has developed a new KALTGAS application for this application. Here, the reactor is cooled using cryogenic nitrogen gas, thus enabling high cooling speeds.

KALTGAS is a temperature control system based on the low temperature of liquid nitrogen as a refrigerant. The liquid nitrogen is vaporized in a cryogenic tank by means of a heater (jet). This generates a constant, cryogenic gas flow. By varying the heater (jet) on the safety controller (SC5), both the cooling capacity and the gas flow volume can be changed, and the LN2 consumption can also be reduced to a minimum by varying the jet power. The cryogenic gas flow is then fed through a vacuum-insulated, flexible metal pipe to a heat exchanger (heater). The heat exchanger has the task of heating the cold gas flow to the desired temperature. This means that a predefined gas flow with a predefined temperature is available as a coolant at the outlet of the heat exchanger. This constant gas flow is passed through a cooling coil suspended in the reaction vessel and cools the medium in the vessel. The cooling coil can be connected to the cold gas system using a quick-release fastener, making installation quick and easy. This KALTGAS system is called direct temperature control for reaction vessels.
In this KALTGAS system, the high cooling rate of the medium in the reaction vessel is achieved by the large temperature difference between the cold gas and the medium to be tempered. A KALTGAS system generates a -180°C cold gas flow within a few minutes. This extremely cold gas flow enables rapid cooling of the medium in the reaction vessel. The standard safety controller (SC5) achieves a temperature stability of the gas flow of less than +/-0.2°C in the regulated state. By using a cascade controller, not only the gas temperature but also the medium temperature in the reaction vessel can be controlled. As the actual temperature approaches the setpoint temperature, this temperature difference is continuously reduced by the temperature controller so that a temperature stability of approx. +/-0.1°C can be achieved in the controlled state.

In addition to the high cooling speed and good control stability, another major advantage of KALTGAS systems is their modular design. By replacing individual components, such as the gas line, the jet or the heater, both the cooling capacity and the cooling speed can be changed. The basic modules, such as the LN2 tank, vacuum pump or temperature control, remain unchanged. Another advantage is the reaction vessel. This can also be fitted with a drain valve in this design. As the temperature is controlled using nitrogen gas, the reaction vessel can be changed without the usual problems associated with thermostatic oil. The cleaning of the reaction vessel is limited to the reaction chamber of the vessel and no longer to the additional cleaning of the tempering jacket.

In a reaction vessel, 1.5 liters of methanol are cooled from +20°C to -95°C within approx. 50 minutes. The LN2 consumption during the cooling phase is 5 – 6 liters of LN2. To keep the methanol at -95°C, the reactor only requires approx. 1.2 liters of LN2 per hour.

Technical data for:

Type TG-RD
Jet = 500 watts
Heater = 400Watt
Reactor = 2 liter volume vacuum-insulated with a viewing strip
Lid = 3 x NS 29/32 side / center 1 x NS 29/32 ; vacuum-insulated
Aluminum frame
Pipe made of V2A, length 1.5 meters, can be evacuated with vac. Pump
Lifter for LN2 container with KF NW 50
Best. No.: TG-RD 40/50

Download cold gas info sheet

Cold gas info sheet as PDF file Download cold gas info sheet

Accessories

LN2 containers from 20 liters to 300 liters volume
Stirrer, agitator and stirrer cap
Reactors with larger volumes

Further KALTGAS system services on request
Subject to technical changes