Timber processing and pelleting in one
The Siat Braun sawmill is one of the largest of its kind in northeastern France. Years ago, recycling and disposal of bark and sawdust produced during timber processing was still costly and cumbersome. New, modern heating technologies now enable making better use of these materials.
The sawdust is pressed into pellets without any additives to be used as a natural product for heating homes and rooms as well as for industrial plant usage. With the bark, enough energy is produced in a boiler to power a steam turbine. The electricity produced by a generator is fed directly into the public power grid. In addition, water is heated in a condenser with the remaining steam energy of the turbine. The process heat is also used to dry the sawdust for pellet production through a heat exchanger. Good planning paved the way for this efficient and ecologically practical solution.
Well-designed, comprehensive coordination
Very early during the planning phase, Siat Braun chose to install the 8.0 version SIMATIC PCS 7 process control system. The challenge involved drawing up a uniform concept for the various disciplines and suppliers so that all of the areas could be operated over a single system.Evias, a leading national and international process automation provider, drafted a comprehensive engineering guide that stipulated uniform engineering specifications as part of a multiproject framework. As a result, all of the disciplines were required to use the Advanced Process Library right from the start. Mutual addresses and naming conventions were also defined. Thanks to these comprehensive specifications, each discipline was able to independently carry out the programming and partial commissioning using a temporary engineering station.
Throughout the complete project, Evias supported the individual suppliers. As a result, minor problems were immediately resolved. In addition to the central coordination, Evias provided the Swiss company Swiss Combi – W. Kunz dryTec with the complete electrical engineering planning, assembly and installation for a belt dryer needed for the drying of sawdust. The project was also created as a module for the subsequent PCS 7 multiproject. Further subprojects handled by Evias included the entire raw material feed system for the boiler, the supply and installation of the SIMATIC PCS 7 network structure, including the complete operating and monitoring system, a control system for the plant’s central emergency stop circuit as well as the controller for the energy supply connection.
Throughout the project, a large number of functions and options offered by PCS 7 were used. The seamless integration of more than 50 SINAMICS G120 drives and the complete SIMATIC F emergency stop technology, built into seven S7-400 controllers and four additional S7-300 controllers, deserve special mention. Almost the entire signal exchange between the disciplines was implemented using the Plantbus ring topology, thereby significantly reducing additional cabling. Optimal operation of the plant is enabled with the help of a redundant WinCC server, to which four clients are connected. The operating staff in the control room has a total of nine new monitors at its disposal. Rounding off the extensive range of functions is the Alarm Control Center, which forwards important fault messages directly to the cell phones of the operators. In the event of a major incident, the on-call duty personnel and operating manager are automatically notified by cell phone.
Simply convincing: integrated operation
The coordination provided by Evias enabled the integration of diverse system components as well as individual subsections of different suppliers into one large multiproject. As the smooth integration of the subsections demonstrated, the thorough preliminary planning paid off. In total, six individual projects were combined, enabling the mutual use of a uniform library and operating concept while reducing inventory management.
We were able to achieve optimal integrated operability by integrating all of the subsections. In addition, all of our relevant archive data is now stored in one system, enabling us to conduct cross-process analyses and compile reports at any time without any further effort.Jérôme Sittler, Project and operations manager, Siat Braun