Even the best laboratory tests cannot duplicate real-life conditions, and testing in active processes is sometimes inefficient and even impossible. To test measuring instruments under specific conditions and configurations, WIKA USA built its own full-size process unit – complete with a reactor and gas-fired furnace.
Passing the Test: Why WIKA Built a Full-size Process Unit
WIKA’s laboratories for testing and design are among the best in the world. In these controlled environments, we carefully and methodically test our instrumentation used for temperature, pressure, flow, level, and force measurement. In some cases, we commission third-party institutes to validate our results.
However, laboratory testing is not always good enough. For certain processes, a simulated environment cannot duplicate actual conditions.
For temperature instruments used in process plants, the ideal is to test in an active unit, but the drawbacks are time, cost, and practicality. Refineries and petrochemical plants need to keep operating to remain profitable, and shutdowns should be limited to just maintenance and repairs. Tests do take place during these scheduled shutdowns; indeed, some instrument testing begins during a turnaround (TA) and are left running until the next one. The problem is that these specific conditions are fixed for literally the long run, as TA cycles often last four or more years. That would make for a mighty lengthy test!
What’s more, a test may require actions that would be unacceptable in an actual situation. For example, peened thermocouples are hammered into small holes drilled into furnace tube walls. This process is fine in a laboratory setting, but doing so in an active process unit would weaken the tube wall and create potential failure points.
To properly test WIKA’s portfolio of thermocouples and other measurement instruments, we came up with a solution that combined the best of both worlds: an actual process unit that our engineers could start, stop, and manipulate as needed – all without having to inconvenience anyone in the process industry.
WIKA’s Design Center and Testing Facility
Before breaking ground on this world-class testing facility, our specialists spent years consulting with multiple industry experts, licensors, and end users. After getting their feedback, we embarked on a multimillion-dollar initiative to build a 6,000 sq. ft. (557 sqm) research and development campus in Pasadena, Texas – not far from the dozens of refineries in the heart of the Houston Ship Channel. The centerpiece of this campus is a full-size, active process unit that was designed and built in accordance with ASME and API guidelines.
The unit, which started operations in mid-2019, works with media ranging from liquids to vapors and mixed-phase fluids. There’s also an innovative system of furnace walls that can adapt to almost any test condition. The 9.6M BTU furnace is capable of replicating a wide range of the processes that take place in larger-scale furnaces and reactors.
This state-of-the-art unit allows our teams to obtain real-world data on WIKA’s comprehensive portfolio of measurement instruments, including the following ETM (electronic temperature measurement) products:
- Gayesco Flex-R®multipoint thermocouple assembly (model TC96-R)
- WIKA V-PAD®tubeskin thermocouple (model TC59-V)
- Gayesco XTRACTO-PAD®tubeskin thermocouple assembly (model TC59-X)
- Gayesco REFRACTO-PAD®tubeskin thermocouple assembly (model TC59-R)
The facility also allows us to develop and test the next generation of instruments for refineries and petrochemical plants.
Real-life Testing in a Real-life Process Unit
With a full-size and fully functional process unit, we can perform a variety of tests and verifications that weren’t possible before. In addition to putting our measurement instruments through actual working conditions, we now can recreate real problems that our end users’ units sometime experience – maldistribution, hot spots, and channeling, to name a few – and to see how those conditions affect ETM instruments.
To that end, our test facility has been invaluable in two applications: furnace condition monitoring and computational fluid dynamics.
Furnace Conditioning Monitoring
Furnace condition monitoring (FCM) is a process by which users collect on-site data to identify performance gaps. They can then use this information to optimize the positioning for thermocouples and tubeskin assemblies, as well as to make other operational improvements for better performance.
With FCM at the testing facility, we are able to:
- Conduct field assessments of a furnace’s thermal conditions by using advanced diagnostic tools, including infrared (IR) imaging and other instruments.
- Review preliminary findings with the customer’s furnace and inspection specialists, operation managers, and others.
- Issue a furnace performance report and our recommendations.
- Provide assistance and advice in thermocouple selection, materials, and engineering for optimal unit life.
- Provide and/or supervise the installation of tubeskin thermocouple sensors to improve temperature monitoring and enhance furnace performance.
- Set up monitoring programs for critical heaters.
What’s more, the R&D campus has become a natural place for hands-on training for customers to get the most out of our measuring instruments and their process units. These best practices are the result of FCM and include how to:
- Increase unit capacity through furnace optimization and debottlenecking.
- Improve energy efficiency with optimal furnace combustion management.
- Use reliability assessments to reduce unscheduled shutdowns.
- Reduce maintenance costs through better TA planning.
Computational Fluid Dynamics
Feedstock, catalysts, vapors, end products – all these fluids move and flow. That’s why a refinery or petrochemical plant should be concerned with computational fluid dynamics (CFD), as this process simulates, analyzes, and solves problems in fluid flow. CFD uses numerical analysis, data structures, and computer calculations to model fluid flow and its interactions with boundary conditions.
Through CFD modeling, we can understand complex phenomena with simultaneous information about mass, momentum, and heat transfer. We can then use this data to plan advanced tests, validate and fine-tune boundary conditions, and develop customized solutions.
Insights From Testing
Ever since the process unit starting running in mid-2019, we have performed a variety of tests using more than 50 sensors for benchmarking, and have analyzed multiple IR scans and images. Here are three of the most interesting insights:
1. Typical longitudinal heat flux distribution in a vertical heater for gas firing
- Heat increases and peaks toward the end of the firebox (symmetric configuration).
- The highest tubeskin temperatures are normally where high heat flux and high process temperatures occur.
2. Horizontal fired box heater with symmetry along the axis of firing
Heat flux increases along the length, does not max out at the centerline, and gets skewed toward the upper region. Understanding the equipment characteristics is key to furnace performance. This helps WIKA’s temperature specialists understand the best locations for each individual test. It also illustrates ho each of our customer’s furnaces are unique. All these variations require a high level of furnace expertise to get the most out of a temperature monitoring system.
3. Typical circumferential heat flux distribution in a single-side fired tube
- Heat increases and peaks toward the tube centerline (symmetric configuration for tubes facing the flame).
- On the tube, highest skin temperatures are normally where high heat flux and high process temperatures occur.
- Spatial as well as circumferential location is important when placing thermocouple.
Customers: The Heart of WIKA’s Business
WIKA is a global leader in instrumentation, but the company is more than just products. After all, sensors and gauges alone do not meet customers’ needs. Our goal is to apply our products to solve tough problems and provide long-lasting solutions. We are your application-focused partner.
This new testing facility in the Houston area is simply the latest step toward our goal of anticipating and meeting end users’ needs. Laboratory results have their place and are sufficient for many applications. However, real-life testing in a full-size working process unit produces the most reliable data for oil and gas applications. More importantly, we can now replicate – not just simulate – your issues, and then optimize the solutions.
With more than three decades of experience in the refining and petrochemical industries, Robert Torgerson is one of the world’s leading subject matter experts for multipoint thermocouple applications. He graduated from Vanderbilt University with a degree in industrial engineering and has been with WIKA USA since 2004. His specialty is creating innovative solutions for difficult temperature measurement challenges in refining and petrochemical applications.