One of the best applications for wireless instrumentation is in older tank farms. A Tank Storage magazine article, Modernising Old Tank Farms to Meet New Requirements shares why. The article’s author opens:
When most tank farms were built, automation was costly. Therefore most storage tanks have a bare minimum of instrumentation and rely heavily on manual checks.
Minimal instrumentation is no longer sufficient from a safety, environmental and regulatory perspective. More instrumentation and automation is required to meet these demands. And, digital devices and communications have been replacing the older analog ways.
Digital signals can be transmitted perfectly, without error, for complete fidelity, and can be repeated and replicated infinitely. Digital signals also have near zero marginal cost, once the investment in the network has been made, many signals can be added at little or no cost.
One of the challenges in modernizing has been the wiring to connect the instrumentation and the controls:
Tanks usually have no spare wires available for additional instrumentation. Tank farms are usually located some distance away, they are large and are separated by roads, tracks, drains, and ponds preventing trenching to lay cable. Cable would be costly and risky since digging may damage other cable or piping.
The article describes numerous applications where additional wireless measurements can improve the overall performance of the tank farm. These applications include:
- The Smart Storage Tank
- Inventory Management
- Floating Roof Tilt and Water Pooling
- Hydrocarbon Leak and Spill
- Secondary Overfill Prevention
- Pump Vibration
- Valve Position
- Modernizing Tank Gauging System
- Modernizing Valve Automation
- Tank Farm 4.0
I’ll recap one of these applications and invite you to read the article to learn more about the rest. To address inventory management:
Tank modernisation often includes replacing existing level gauges. By using wireless communication for the inventory measurements the existing cable is now freed up and can instead be used for SIL-rated overfill protection signal to a safety system. The two signal paths work in parallel.
By wirelessly connecting the tank measurements to the control system, instead of being stranded locally at each of the tanks:
Operators now monitor all tanks from a centralized location reducing man-hours spent on operator rounds. The site planned not only for the instrumentation that was being installed on the current project, but made the gateway easily accessible to instruments installed in the future. The wireless network can easily accommodate new measurements. Several points which had not been monitored in the past are now measured.