Process and Tools Integration Introduction to Operability and Control of Integrated Plants 8. August 2005 Sten Bay Jørgensen CAPEC - Department of Chemical Engineering Technical University of Denmark, DK-2800 Lyngby, Denmark C APEC

8. August 2005 Process and Tools Integration Overview Motivation Generic Chemical Plant Ammonia reactor example Study of consequences of process integration –Linear analysis –Examples of Nonlinear analysis Control consequences

8. August 2005 Process and Tools Integration Generic Chemical Production Plant Process integration is mandatory for energy and rawmaterial efficiency Recycle streams destabilize plant performance - moves poles towards RHP

8. August 2005 Process and Tools Integration Ammonia Reactors Operating point: Feed temperature Feed concentration Feed flow rate Pressure No automatic control of inlet temperature 3-bed quench reactorsimple reactor

8. August 2005 Process and Tools Integration Industrial case Naess et al. (1993) –Oscillations in an industrial NH 3 reactor after decrease in pressure and flow rate. –Steady state was regained after increase in pressure Morud and Skogestad (1998) –As the heat exchanger efficiency is increased, a Hopf bifurcation occurs. Morud, J. C. and Skogestad, S. (1998). AIChE J., 44, pp Naess, L., Mjaavatten, A. and Li, J.O. (1993). Chem. Eng. 17 no. 5/6 pp bed quench reactor with energy recycle

8. August 2005 Process and Tools Integration Course aims at providing Understanding how process dynamics are affected by recycles Understanding how control is affected by recycles Some results of nonlinear analysis of integrated plants Guidelines for control design of integrated plants