Method and apparatus for measuring the temperature in reactors

A method of directly measuring the temperature in an elevated pressure reactor, comprising the steps of:

• selectively reciprocating a temperature sensor between a measurement position at the reactor interior and a fully retracted position exterior of the reactor, the measurement and retracted positions comprising opposite ends of a sealed measurement channel which includes a bore through the reactor wall;
• and
• alternately closing the measurement channel intermediate its ends when the temperature sensor is in its retracted position so as to isolate the sensor from the interior operating atmosphere of the reactor, and opening the measurement channel for at least one fully reciprocated movement of the temperature sensor along the channel for directly measuring the internal reactor operating temperature;
• said selective reciprocating movement of the temperature sensor being controlled by a process computer controlling the rate of sensor movement along the measurement channel based upon the temperature sensed by the sensor and the position of the sensor along the measurement channel.

A method of directly measuring the temperature in an elevated pressure reactor, comprising the steps of:

• selectively reciprocating a temperature sensor between a measurement position at the reactor interior and a fully retracted position exterior of the reactor, the measurement and retracted positions comprising opposite ends of a sealed measurement channel which includes a bore through the reactor wall;
• alternately closing the measurement channel intermediate its ends when the temperature sensor is in its retracted position so as to isolate the sensor from the interior operating atmosphere of the reactor, and opening the measurement channel for at least one fully reciprocated movement of the temperature sensor along the channel for directly measuring the internal reactor operating temperature;
• and
• pressurizing the measurement channel at the retracted position with the channel closed intermediate its ends and the temperature sensor disposed at the fully retracted position to a pressure at least as great as that existing in the reaction space so that when the channel is subsequently opened for reciprocated temperature measurement movement of the sensor from the retracted position, reaction byproducts in the reaction space are not drawn into the channel.

In a reactor wherein the interior temperature is indirectly measured on a continuous basis by calculating the interior temperature from selected operating characteristics of the reactor, a method of periodically verifying the accuracy and reliability of the indirect temperature measurements by direct measurement of the interior temperature utilizing an apparatus which includes a temperature sensor comprising a thermocouple enveloped in a heat-resistant protective material, drive means for reciprocally moving the sensor along a measurement channel between a measurement position within the reactor and a retracted position exterior of the reactor, closure means for closing the measurement channel intermediate its ends when the sensor is in the retracted position so as to isolate the sensor from the reaction atmosphere, and a process computer controlling the drive means for selective movement of the temperature sensor along the measurement channel, the method comprising:

• normally maintaining the temperature sensor in the retracted position with the closure means closing the measurement channel,
• periodically operating the closure means to open the measurement channel, and
• selectively reciprocating the temperature sensor from the retracted position to the measurement position under computer control while the closure means opens the channel for directly measuring the instantaneous internal reactor temperature, and then returning the sensor from the measurement position to the retracted position and operating the closure means to close the channel and isolate the sensor from the interior reaction atmosphere.