Enhancing steam methane reformer reliability and efficiency with advanced temperature profiling
Steam Methane Reformers (SMRs) also known as Primary Reformers, are critical furnaces in the oil and gas industry. They facilitate endothermic catalytic reactions within tubes with heat supplied by multiple burners. The vertical catalyst tubes, positioned adjacent to the burners, are subjected to high temperatures, making precise temperature control paramount for achieving desired yields and extending the lifespan of the tubes.
SMR units are particularly susceptible to overfiring, especially during transient conditions. Daily Thermetrics, in collaboration with various process licensors and catalyst providers, offers expertise in both in-tube and tubeskin temperature measurement specifically for Steam Methane Reformers.
IN-TUBE TEMPERATURE MEASUREMENT
Traditional methods for measuring tube temperature, such as pyrometers and reformer imagers, have limitations in providing continuous and accurate temperature readings across all points and timeframes. CatTracker technology provides continuous online temperature measurement, not only of the catalyst but also the tube wall. Providing the best-in-class multipoint system, CatTracker Technology is designed to be in direct contact with catalytic reactions and elevated temperatures, making it suitable for a harsh environment like a Primary Reformer.
Software simulations and real-world applications have proven several benefits of CatTracker:
• Continuous in-tube temperature measurement
• Accurate carbon formation prediction
• Enabling operation at low steam-to-carbon ratios through simulation
• Improved understanding of catalyst performance
• Determination of pigtail temperatures
• Calibration of pyrometers
• Avoiding the heat sink effect during transient periods
CatTracker can be integrated into existing SMRs with a minor modification of the top flange or the utilisation of a Y-piece in case the process inlet is through the top flange. This technology enables 11 sensing points within a single ¼” OD thermocouple, therefore ensuring minimum catalyst displacement. With this convenient tool, continuous start-up, normal operation and shutdown temperature monitoring is enabled.
TUBESKIN TEMPERATURE (TWT) MEASUREMENT
Measuring tubeskin temperature at SMR furnaces is one of the most difficult tasks due to the furnace type as well as elevated temperatures. Daily Thermetrics has worked with various licensors and operators around the globe to engineer tubeskin thermometry solutions that are among the highest reliability reported in the industry.
For an SMR furnace, which is a “critical” heater, the thermocouple entry location as well as routing inside is crucial for enhanced thermocouple reliability and therefore lifetime due to multiple heaters around the tubes. For this, a site survey is recommended to understand obstacles and possibilities in and around the furnace. The number of tubeskin thermocouples and their locations shall be decided utilising site guidelines as well as Daily Thermetrics recommendations from previous installations.
Another important consideration shall be thermocouple and compensation cable specifications as the severity of conditions, most importantly the elevated temperature, flame impingement and flue gas composition shall be examined carefully in order to proceed with correct specifications. Outer diameter of the thermocouple shall be aligned with tube diameters and heavy wall shall be considered for a longer lifetime of sensing points present in the furnace. Daily Thermetrics will be able to help with installations at SMR furnaces.
ACCURACY CONSIDERATIONS
Validation of Installed Measurement Accuracy is crucial to provide a qualified ∆T against as New Built Calibrated Accuracy. While CFD analysis is not practical or proven for each installation point, and pilot heater build trials are good for comparing different measuring junction types but do not provide installed measurement accuracy, Daily Thermetrics TrueTubeTemp Service offers a comprehensive solution.
TrueTubeTemp Service provides fully documented answers to the installed tubeskin thermometry accuracy, including a New Built Calibration Report for each tubeskin thermocouple and a Full Turnkey Installation Service to ensure correct installation. Furthermore, in-situ verification of the TrueTubeTemp is performed after the installation of the skin thermocouples and furnace startup by utilising its Gold Cup pyrometer to measure the true temperature at the installed measuring point.
To obtain highly accurate reference temperature measurements, it is essential to identify any errors caused by three key process variables: tube emissivity, background radiation, and sight path effects. The Gold Cup achieves this by creating near blackbody conditions against the surface of the tube. TrueTubeTemp service can also serve as a calibration reference point for any ongoing third party IR scans. In short, utilising the TrueTubeTemp service provides critical data to document the installed measurement accuracy in order to provide with highest ROI.
Most important of all is undoubtedly the installation of tubeskin thermocouples as all the efforts put in for the design and manufacturing could fizzle out with improper installation. Daily Thermetrics’ Field Services Team is highly skilled and experienced at performing turnkey installations in order to ensure minimised downtime as well as maximised thermometry performance at enhanced lifetime. Daily Thermetrics is capable of providing all required equipment to remove any existing assemblies, welding, as well as post-installation inspection and hardware connections.
By implementing advanced temperature profiling techniques, including both in-tube and tubeskin temperature measurements and validating their accuracy, operators can gain better insights into SMR performance, optimise operations and ultimately extend the lifespan of reformer tubes, leading to improved safety and efficiency.
Deniz Keleş is manager – sales & technology at Daily Thermetrics:
