As part of the decarbonization of its syngas plant at the Stade site, Air Liquide implemented round-the-clock monitoring of a new reactor. This allows the continuous process to run without unnecessary interruptions. The combination of a thermal camera, WAGO IoT gateway and seamless integration into the process control system ensures that anomalies are detected early and condition-based maintenance can take place.
Since the introduction of CO2 emissions trading in the European Union and Germany at the latest, many companies in the basic materials industry have begun concrete planning to optimize ongoing processes in such a way that fewer expensive certificates will need to be purchased in the future. This exact response was politically intended. Nevertheless, there are companies that have long anchored sustainability in their corporate strategy and invest in climate protection —such as Air Liquide at the Stade site.
Investment in the Future
Successful negotiations for long-term supply contracts resulted in a fundamental retrofitting of the existing systems in Stade, one of the largest chemical production sites in Lower Saxony. Air Liquide, which specializes in industrial gases, invested nearly 40 million euros over the past year in this location. The project aimed to make syngas production more efficient and environmentally friendly. In addition to the modernization of two air separation systems, the focus quickly shifted to the partial oxidation system (POX). Previously, CO2 produced alongside hydrogen and carbon monoxide was released into the environment. The new system increases energy efficiency by approximately 15% and reduces CO2 emissions by about 15,000 tons annually, which equates to 80% of the site’s direct emissions.
Air Liquide is very proud of this innovation, which has positively impacted the environment. “The new, 16-meter-high reactor for our partial oxidation system is particularly impressive. It weighs 58 tons, and its delivery time is more than a year. The reactor’s protection, now and in the future, was our top priority,” said Hendrik Gollek, a project engineer in Automation for Cluster Central Europe in Düsseldorf. Gollek collaborated with Air Liquide’s northern facilities technical team to ensure the project’s success.
Reliable Assessments Required
Due to the extreme reaction conditions of around 30 bar and over 1000 °C, the interior of the reactor is lined with fireclay bricks. There are only a few technical options available to detect the inevitable degradation of this lining over time. All of them are either expensive, produce ambiguous results, or both. Air Liquide therefore sought a method that could provide a reliable assessment of the condition without having to shut down the reactor for inspections “just in case” or on a rigid schedule.
Start-up procedures after a shutdown are inefficient and costly. To avoid this, Air Liquide’s experts proposed early hazard detection using industrial thermal cameras. The system selected was Prometheus from TTS Automation, which detects temperature anomalies and is based on intelligent control technology from WAGO, such as the PFC200 from the 750 series. The system detects thermal anomalies regardless of other environmental conditions.
“The package of our cameras, the 750 series control technology, and WAGO’s edge computers is used in many chemical industry plants. There, it detects situations before they become hazardous,” explains Thomas Striegel, Managing Director of TTS Automation. This anomaly detection is also used at Air Liquide. It provides preventive maintenance indicators that operators can act upon to plan their production accordingly.
The new system warns long before the outer metal casing would burn through. In such a case, Air Liquide shuts down the process in a controlled manner. The reactor is flushed, and the inner protective lining is repaired. Thanks to WAGO technology, the process only needs to be stopped if a defect is actually present—not just for inspection purposes. The second advantage is that it is possible to intervene at an early stage, i.e. in the case of small or localized damage. It would take months to completely reline the container, whereas patching minor defects only takes a few days. If the outer shell were to become damaged, a new reactor would be needed. This would lead to a significantly longer plant shutdown, along with corresponding costs and production losses.
Seamless Integration into the Automation Landscape
A key reason the engineers at Air Liquide chose the combination of camera system and WAGO control technology was the future viability of the solution. “It was important for us not to operate the measuring system as a stand-alone solution, but integrated into our Yokogawa process control system. That minimizes manual work and its disadvantages, such as time consumption and susceptibility to errors,” says Gollek. For complete monitoring, two sets of three cameras arranged radially around the reactor, plus one camera looking down from above, are sufficient. These seven cameras, installed in the upper, hot half of the reactor, display all relevant information in the control system: maximum and minimum values, divided into sectors. Together, fixed alarm thresholds were defined that only trigger warnings when exceeded or fallen below.
The camera software runs on the WAGO IoT Box. No translator is required and no contacts need to be transferred or wiring carried out. The gateway speaks the same language as the TTS camera. A key argument for integrating with the WAGO IoT Box was its interface with the control system. “Seamless integration of such devices into process industry environments is our specialty. With our solutions, Air Liquide can utilize all camera functions and process the raw data. Moreover, managing and analyzing anomaly data at the PLC level reduces system load and enables operators to communicate directly with the camera electronics from the control system,” explains Wolfgang Laufmann, Business Developer Smart Factory at WAGO.
At the same time, interfaces are an issue in every system. “It doesn’t really matter what the user requires, whether Modbus TCP, OPC UA, MQTT, telecontrol protocol or another interface to connect to a Scada and/or cloud system. Our toolbox is large and we have been able to implement every custom solution quickly and easily so far,” says Laufmann. This aligns with another advantage: relatively low cabling effort. Cameras, gateway, and control system are not networked via standard field instrumentation with potentially additional distributors, but rather via thin fiber optic cables. At Air Liquide in Stade, no scaffolding or field distributor installation was required. “That’s a cost-efficient installation WAGO is offering us here,” confirms Gollek.
“But right now, I’m just happy that so many internal and external experts are helping save tons of CO2 in the new plant—and that with the surveillance camera and WAGO IoT Box, we’ve installed a simplification for maintenance. In the best-case scenario, we’ll run straight through until the next major overhaul in five years,” Gollek laughs.
"The great advantage of the WAGO and TTS system is that it functions like an early warning system. Damage occurs rather gradually in the reactor, so we have the opportunity to inform our customers in advance. They can then adjust their production, and we can shut down in a controlled manner, make repairs, and then quickly restart."
"Seamlessly integrating devices like industrial cameras into process industry production environments is our specialty. Managing and processing data at the PLC level reduces system load, and operators can access field devices directly from the control system."
Text taken over from original – WAGO
