Application of sapphire thermocouples in gasification reactors

Gasification reactors, because of their harsh process conditions, place high demands on the instruments used there. Many manufacturers have reacted to the and adapted their products correspondingly. But what are the optimisation possibilities for thermocouples for use at higher process pressures?
The challenge: ? Spell-binding ?
In a gasification reactor, there is an extremely 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 regarding the 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 behind that is its monocrystalline structure. The sapphire-design thermocouple has, as a result of 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.
Advantages of a sapphire thermocouple
three times longer service life in comparison to purely ceramic thermowells because of the monocrystalline structure of the sapphire thermowell
High process safety with processes around 1,700 �C and 65 bar
Cost saving because of the elimination of complex purge systems and valves and fittings for flow measurement
Reduction 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 primary sealing serves as protection contrary to 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 due to 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 designed for use in gasification reactors. More info on the TC84 are available on the WIKA website and inside our flyer.

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