| The reverse osmosis desalination pilot plant at the University of Louisville was modified in order to study the application of advanced control strategies on a hollow fiber membrane module; specifically, a B-9 PermasepRTM Permeator by Du Pont. The objective of the study is to compare the performance of standard Proportional-Integral (PI) control with the performance of a constrained model predictive control (CMPC) software called ONLINERTM. A proper control strategy, whether it be PI or CMPC, should allow for the manipulation (servo control) of the product flow rate while maintaining product quality. In doing so, a plant can adjust the production of water to meet demand.; Several PI control experiments involving set point changes in product flow rate and conductivity (a measure of quality) were conducted. It was found that PI control was unable to properly control the quality of the product by means of manipulating the pH of the feed. The PI controller over-compensated for offset in product conductivity. In contrast, ONLINE RTM displayed superior performance in the control of the pilot plant by holding the process outputs within specified bounds; especially the feed pH which prevented controller run away. Furthermore, ONLINERTM was able to maximize the product flow rate by 13.6% while improving the conductivity (quality) by 1.1%. |
