Application of sapphire thermocouples in gasification reactors

Gasification reactors, due to their harsh process conditions, place high demands on the instruments used there. Many manufacturers have reacted to the and adapted their products correspondingly. But which are the optimisation possibilities for thermocouples for use at higher process pressures?
The challenge: ?Gasification reactors?
In a gasification reactor, there’s an exceptionally aggressive process atmosphere and, with that, the chance of poisoning of the noble metal thermocouple. The procedure conditions often result in shutdowns and interruptions in operation. Profitability and safety aspects are thus two important themes in connection with the instruments used in them.
WIKA sapphire-design thermocouple TC84
Approach to resolution: Sapphire thermocouple
By using a sapphire protection tube, the high-temperature thermocouple is protected from poisoning by the aggressive process atmosphere during operation. The reason for that is its monocrystalline structure. Flirt -design thermocouple has, due to its construction, a significantly higher service life than other high-pressure thermocouples and, therefore, plays a part in a clear decrease in the process downtime.
Benefits of a sapphire thermocouple
3 times longer service life in comparison to purely ceramic thermowells due to the monocrystalline structure of the sapphire thermowell
High process safety with processes up to 1,700 �C and 65 bar
Cost saving because of the elimination of complex purge systems and valves and fittings for flow measurement
Reduced amount of unplanned downtime
Increased safety against escape of toxic media through double sealing system
Construction of the TC84 sapphire-design thermocouple
Special construction of a sapphire thermocouple
The special construction of a sapphire thermocouple provides increased safety.
The principal sealing serves as protection against the escape of toxic process gases at high pressures and also at high temperatures
The secondary sealing may be the safeguard in the event of a malfunction in the principal seal because of any unforeseeable disturbance to the primary seal
The ceramic outer thermowell serves as protection against harsh process conditions
The sapphire protection tube protects internally against contamination of the thermocouples through diffusion
Note
WIKA is rolling out the TC84 sapphire-design, high-temperature thermocouple specifically for used in gasification reactors. Further information on the TC84 are available on the WIKA website and inside our flyer.

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