CHE430 Process Control Midterm Notes 2014

Notes for Process Control: BIBO: bounded input, bound output Fit #1: method uses tangent o the process reaction curve at the point of max rate of change. Fit#2: used tangest line for lower value of t, but used 63.2% of process gain for upper limit t2 Fit#: no tangent line, but use 28.3 and 63.2 for t1 and t2 respectively Tau = 3/2(t2-t1) Thata = t2-tau Give the reasons for which chemical processes require a control system. Process safety Performance Product quality Making it stable Interatction Process dead time Stability is theability of a response to remain bound (remain within the limits) System is stable if all the roos of the denominator of its transfer function are either negative real numbers or complex numbers with negative real parts.