Blow-Thru Control

For efficient paper drying in the dryer section, condensate must be removed from dryers at the same rate of condensate formation. A fundamental challenge in dryer drainage systems is establishing the “right” independent variable to control for efficient dryer drainage and ability to respond to changing conditions. Deublin Blow-Thru Control solves this problem by controlling to a setpoint variable which establishes the ratio of blow-through to condensate to an engineered and optimized value. The amount of differential pressure across the steam and condensate headers (DP) will automatically and continuously adjust as operating conditions are adjusted. As dryer pressure increases, the DP will automatically rise; as dryer pressure decreases, or on a sheet break, the DP will drop. But the ratio of blow-through to condensate will remain the same. At high condensing loads, or pressure increases, the dryers will not flood. On a sheet break, the system will not vent or waste excess blow-through. The Deublin Blow-Thru Control system achieves this without special logic or secondary software. The controlled variable for the drainage control loop is simply changed from the traditional header-to-header DP, to controlling to the blow-through measurement. Deublin achieves this using Deublin Process Simulation, in which the efficient design and sizing of all equipment and piping are analyzed and optimized for every dryer section. The proof of performance lies in hundreds of installations worldwide with dramatic and immediate improvements in dryer drainage performance.