Dynamic simulation and control of a multi purpose chemical plant

Abstract

The aim of this work is to investigate the dynamicbehaviour of a typical multi-purpose chemical plant undervarious control structures.The mathematical models for the processing units of thistypical chemical plant are developed. These models includeas many as possible of the effects present in chemical plants.Therefore a continuous stirred tank reactor, a separation step(distillation), a heat exchanger, mixing tanks and recycle stream, ` ... ' ; were included in the model chemical plant. The m~thematicalmodels are focused on the control objectives and needs of eachindividual unit independently,· and then the model control structuresare integrated for the control of the compelete plant.During the integration of modal control structures overspecifications(conflicts) between the control loops are eliminated by the useofa systematic procedure.A computer program is developed to solve the differentialand ~gebraic equations resulting from the mathematical modeling,and alternative flowsheets, with their control structures, forthe model plant are simulated by this' computer program.From the simulation results it was concluded that.~hesuggested control structures for the plant fulfill the operationalobjectives of the plant. Furthemmore, it was shown that thisresults was obtained upon the use of the systematic procedureused for total plant control to avoid ov~ specifications amongthe control loops of the plant.