Biopellet Magdeburg GmbH & Co. KG operates a biomass heating plant that burns natural wood chips among other materials. The heat produced by the plant is also used to provide energy to the adjacent wood pellet mill. To transport the material from the wood chip storage yard, the facility relies on a fully automated crane system. Precise crane positioning proved to be a major challenge because the yard is often full of steam that renders the use of conventional optical sensors impossible.
To address this issue, the company equipped the crane bridge with two passive radar sensors from Symeo for centimeter-precise positioning. The maintenance-free sensors transmit signals in the 61GHz range, which are reflected by simple metal reflectors. The radar-based Symeo distance measurement works reliably and with high precision even in the case of heavy dirt and steam.
With the passive radar solution, the automated wood chip handling system now operates more efficiently. The crane positions itself on the border of the individual storage areas with centimeter-accuracy, directly in front of the perimeter wall. At the same time, active positioning prevents collisions between the gripper and the wall.
The CO2-neutral biomass heating plant was built in less than a year and generates electricity and heat from the combustion of wood chips, amongst others. With a fuel heat output of 13MW, the power plant can provide around 7.8MW of thermal output and around 1.9MW of electrical output. The electricity is fed into the public grid under the Renewable Energy Sources Act, while the heat generated is supplied to the neighboring pellet plant as well as sold to other industrial companies in the business park. In the wood chip storage yard, a fully automated crane system from Schmiedl Metall und Fördertechnik GmbH is used to transport the material, which is stored according to different stages of quality. The steam from the plant excluded the use
For this application, Symeo has just the right radar sensor in its product portfolio. The sensor is passive, which means it can operate without an active target at the other end. It can also be deployed in harsh environments where steam, vibrations or dirt are common. The passive measurement only requires two components: a passive radar sensor and a metal mirror that serves as a clearly visible radar target.
Two passive sensors were installed on the crane bridge, sending signals in the 61GHz range, which are then reflected by two metal mirrors. One mirror is mounted on the crane trolley, the other on the far end of the building. Measurement without a metal mirror on a straight, reflective surface is also possible as an option. Because the sensor features a beam angle of ± 2° and does not require precise alignment with the reflector, installation is extremely quick and easy.
„We searched a long time for a solution that would allow us to position the crane under difficult conditions such as those found in the wood chip storage area. With the passive radar system from Symeo, we can reliably detect the position of the crane down to the centimeter using only two components, despite the extensive amount of steam that surrounds the storage yard. Decreased boiler output caused by inhomogeneous fuel input and collisions between the crane gripper and perimeter walls are meanwhile a thing of the past,“ says Dirk Zober, plant manager at Biopellet Magdeburg GmbH & Co. KG.
Both the passive radar sensor and the stainless steel mirror feature a robust design with no moving parts, which means they require no maintenance and are free of wear and tear. Depending on the environment, the system has a range of up to 100 meters. Symeo offers additional products for longer distances.
The Symeo passive radar system has now been in operation at the biomass heating plant in Magdeburg for more than ten years without any outages.
Facts & Figures
Biopellet Magdeburg GmbH & Co. KG operates a biomass heating planting in Rothensee on the outskirts of Magdeburg. The heart of the system is an innovative boiler that burns natural wood chips in several stages. Apart from serving as a sustainable source of energy, the downstream ORC system also extracts heat for the state-of-the-art mill that produces industrial-scale and DIN pellets from wood chips. | www.bp-md.de