Approximately 100 AUMA Seven actuators ensure high-performance valve automation at Skærbæk CHPP near Fredericia, Denmark. Originally built for natural gas, the plant operated by Danish energy company Orsted has recently been converted to dual-fuel cogeneration. The plant provides sustainable district heating for roughly 60,000 households.
Two highly efficient 154MW wood chip boilers were installed during the refurbishment. Wood chips are the primary fuel, with natural gas as a backup. Installing the new boilers required new pipelines for water and steam to be installed and linked to the original gas-fired plant. Around 100 AUMA Seven actuators with Profibus interface were added.
The actuators, which are engineered by AUMA Group company Sipos Aktorik, incorporate frequency converters that allow their operating speeds to be adjusted during the valve travel. Variable speed offers significant advantages in a wide variety of closed-loop and open-loop control applications, since each change of valve position can be matched to its optimum operating speed.
Variable-speed operation also makes the actuators very versatile, since a single size of actuator typically covers 8 different torque settings and 7 operating speeds. This reduces the number of actuator variants required across the plant, and so simplifies inventory management. Torques and speeds can be adjusted at any time to optimise the process or accommodate process changes.