Apparatus & process

In a reactor tube in which a plurality of catalyst carriers are disposed, each catalyst carrier is an annular container having a perforated inner wall defining a tube, a perforated outer wall, a top surface closing the annular container and a bottom surface closing the annular container. A surface closes the bottom of the tube and a skirt extends upwardly from the perforated outer wall of the annular container from a position at or near the bottom surface of the container. A seal is located at or near the top surface and extends outward from the container beyond an outer edge of the skirt. The reactor tube additionally includes a temperature measuring device configured to measure the temperature in two or more catalyst carriers within the reactor tube.