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Operating charts for continuous sedimentation. III: Control of step inputs. (English) Zbl 1189.76667
Summary: [For parts I, II, IV see respectively ibid. 41, No. 2–3, 117–144 (2001; Zbl 1128.76370); ibid. 53, No. 2, 139–185 (2005; Zbl 1086.76069); ibid. 60, No. 3–4, 249–264 (2008; Zbl 1154.76047).]
The main purposes of a clarifier-thickener unit is that it should produce a high underflow concentration and a zero effluent concentration. The main difficulty in the control of the clarification-thickening process (by adjusting a volume flow) is that it is nonlinear with complex relations between concentrations and volume flows via the solution of a PDE – a conservation law with a source term and a space-discontinuous flux function. In order to approach this problem, control objectives for dynamic operation and strategies on how to meet these objectives are presented in the case when the clarifier-thickener unit initially is in steady state in optimal operation and is subjected to step input data. A complete classification of such solutions is given by means of an operating chart (concentration-flux diagram).

MSC:
76T15 Dusty-gas two-phase flows
76N25 Flow control and optimization for compressible fluids and gas dynamics
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