The iterative feedback tuning approach is used to design decentralized PID controllers for an ideal two-product reactive distillation column. The method is compared with relay feedback tuning including TyreusÀLuyben tuning rules. A control structure where two tray temperatures are the controlled variables and the feeds are the manipulated variables is considered. It is shown that iterative feedback tuning gives superior performance, compared to standard relay feedback.
Die Trennung von Partikelkollektiven erfolgt meist anhand der stationären Sinkgeschwindigkeit als Trennmerkmal. Die Bewegungszustände der Partikel werden bisher sehr aufwendig durch die numerische Lösung des Kräftegleichgewichts ermittelt. In dieser Arbeit werden algebraische Gleichungen hergeleitet, die die zeitlichen Ä nderungen von Sinkgeschwindigkeit und -weg bei laminarer und turbulenter Partikelumströmung beschreiben und lediglich von der Partikelgröße, -dichte und -form abhängen. Unabhängig von der Anfangsgeschwindigkeit lassen sich charakteristische Werte ermitteln, mit denen der Zeitpunkt abgeschätzt werden kann, ab dem eine ausreichende Annäherung an die stationäre Sinkgeschwindigkeit erreicht ist.
Unsteady Settling of Solid Particles in Laminar and Turbulent FlowSeparation of particles is often designed based on the terminal settling velocity as separation parameter. Until now, the particle state of motion is described by solving the force balance equation numerically, which is highly complex. In this work, algebraic equations are presented, which describe the temporal changes of the setting velocity and the displacement at sinking in laminar and turbulent flows around the particle. These equations solely depend upon particle size, density and shape and are independent of the initial velocity. Using the characteristic values, the time period where a sufficient convergence to the terminal sinking velocity is reached, can be clearly identified.
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