Emerson Introduces Rosemount® Thermocouple with Sapphire Thermowell, Ideal for Extremes of Gasification Reactor Applications

New sensor with gas-tight thermowell extends service life threefold under severe temperature and corrosion conditions

 Emerson Process Management introduces a Rosemount® thermocouple with gas tight sapphire protective tube for use in gasification reactor applications. The new thermocouple has been specially developed to give an extended operating life in difficult process conditions, where temperatures up to 1800° C, pressures up to 110 bar, and attack from aggressive gases, lead to the premature failure of standard thermocouples.
 
The Rosemount insulated thermocouple is enclosed within a special protective tube manufactured from commercially grown sapphire, which, like the naturally occurring variety, is corrosion resistant and impermeable to gases. The improved design enables accurate and reliable measurements over a significantly extended sensor life of 6,000 to 18,000 hours (depending on the application). This is typically three times the life of a standard thermocouple. By reducing the number of unplanned shutdowns due to sensor failure, production output is increased. Life time costs are also reduced since the longer operating life reduces the number of replacement sensors that are required.
 
A feature of the Rosemount design is the hermetic sealing of the sapphire protecting tube to the supporting bushing. This enhances safety and provides the longest life time for this type of thermocouple in gasification reactors. In the event that the probe breaks, there is a redundant seal system that prevents toxic emissions from being released from the reactor. All of the seals are pressure tested with Nitrogen at 110 bar before delivery. The connection housing is made from forged steel, which avoids the leakage of hydrogen containing gases from the reactor.
 
The new high temperature thermocouple assembly can be used with the Rosemount 3144P temperature transmitter for critical control and safety applications. The predictive thermocouple degradation diagnostics contained within the transmitter can further improve plant availability by providing an alarm when the resistance of the thermocouple changes. This enables maintenance staff to plan the change out of the thermocouple prior to an unplanned shutdown, minimising cost and plant downtime.
 
The new Rosemount thermocouple with sapphire protection tube is suitable for a wide range of applications in the oil and gas, agriculture, refining and chemical industries. It joins Emerson’s existing line up of Rosemount temperature sensors and accessories for applications in industrial environments where high accuracy, durability, and long-term stability are required.