SIMULATION OF AN INDUSTRIAL SEMIBATCH NYLON-6 REACTOR - OPTIMAL PARAMETER-ESTIMATION

This work presents a comprehensive computer simulation study for the h ydrolytic polymerization of epsilon-caprolactam with the vaporization of both water and e-caprolactam in an industrial semibatch reactor. It incorporates various correlations for heat and mass transfer, desorpt ion from the free surface as well as bubbly desorption, and the build- up of pressure in the reactor. The solution of the mass and energy bal ance equations is carried out using Gear's algorithm. Optimal values o f five parameters are obtained using the Box complex technique with in dustrial data for a feed-water concentration of 3.45 mass%. Simulation results are then obtained for two other feed-water concentrations usi ng these curve-fitted parameter values. Excellent agreement is obtaine d with the corresponding industrial data. The activity coefficients of the monomer and water have been correlated with monomer conversion in this study. This eliminates infeasible solutions under certain condit ions. The sensitivity of the model results to changes in the values of several parameters is also studied. The model developed can be used t o optimize the performance of the reactor.