Advanced Imaging


Advanced Imaging Magazine

Updated: July 8th, 2008 05:26 PM CDT

How to... Improve Safety Monitoring of Pressure-Vessel Shell Temperatures

Software displays real-time, color-coded images with temperatures in 32 user-defined Regions of Interest (ROI's) on the vessels.
The Mikron cameras are mounted in sealed environmental enclosures with IR transparent windows.
The largest radiometric imaging system for safety monitoring of these petrochemical processing vessels uses14 Mikron IR cameras and MikroSpec R/T Software.

Partial-oxidation vessels in the petrochemical industry operate at about 1000 psi, with internal temperatures of 2600°F and exterior temperatures ranging from 200°-500°F. A refractory lining protects the steel shells. Breakdown of the lining can lead to catastrophic failure, so monitoring shell temperatures is a critical safety issue.

The standard monitoring system uses a thermocouple-grid system fixed to the exterior. Failures of thermocouples or the cabling create holes in the grid until repair can be made, which is difficult during operation. The grid output also degrades soon after installation because it is in direct contact with the shell. And, the grid must be removed and reinstalled whenever work is done on the vessel internals.

A new non-contact system of infrared cameras and software is now allowing operators of these vessels to literally “see” thermal behavior and monitor skin temperature in real time. Known as a ThermalSpection™ 24 system, it also provides computer-generated alarms for thermal excursions, while storing trend data for analysis and process improvement. The system is applicable to any refractory-lined equipment, as well as reactors, regenerators, boilers and furnace tubes.

A turnkey ThermalSpection system utilizing 14 infrared cameras is currently monitoring two vessels in a partial oxidation system in Texas. Each camera’s 320 x 240 pixel array is the equivalent of 76,800 temperature sensors aimed at the vessel shell. The cameras have a wireless Ethernet board built in. Real-time radiometric images are transmitted to a single PC running MikroSpec™ R/T software, which controls the system.

MikroSpec software allows each camera’s field of view to be subdivided into 32 user-defined regions of interest (ROIs), each with its own alarm limits. Operators can view real-time, color-coded displays of temperature in the ROIs. The system can display multiple camera feeds on a single monitor, or individual feeds on separate monitors. Operators can choose from a range of monitoring/measurement modes, including interval time, difference between points A and B, max/min temperatures in an ROI, temperature range, and multi-spot measurement.

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