Controller Design and Analysis for Automation of Chemical Water Treatment System

Authors

Anirudha Upadhyay (IV Year) Abhishek Agarwal (IV Year)

Electronics & Instrumentation, Electronics & Communication

VIT University, Vellore, Tamil Nadu, India

Abstract

An automatic chemical waste treatment system designed involves a complete modernization of an existing waste water plant; starting from the water collection points, then on to the neutralization and decanting processes, and then finally to the solid waste (mud) drying process. The paper includes design and implementation of a Titration System for sampling waste from purifiers. It includes Implementation of titration system based on microcontroller interfaced with sensors using for sampling waste. Closed loop process offers optimal efficiency by maintaining the concentration at set point by controlling the flow rate of waste feed in purifier. Concentration of the sample is compared by the set point value. PID controller analyzes error and directs it accordingly as set by the reference point in case of positive error. However if negative error occurs the action of PID controller is overwritten using microcontroller based titration system as used for initial titration. It implements feedback PID controller coupled with dead time compensator so as to the control the output concentration at required user defined set point. Feed forward controller anticipates the temperature of the reactor by measuring the input concentration. Also, a cascade controller is implemented to control the reactor core temperature by controlling the flow rate of cooling water. It measures the disturbance before it affects the main variable and takes corrective action. The power of Lab VIEW is utilized for controlling action in plant by implementation of PID and Feed Forward control along with a Cascade. This preliminary study consisted of an optimization of the neutralized and particle-free effluent water returning to the purifier towers. System involves implementing multiple sampling sensors in flow line to measure the concentration throughout the continuous treatment process in order to pinpoint the source of problem in the event of high concentration flowing into waste or leakage. The solid waste separator is implemented mechanically using piston and flapper acting together to separate solid waste and water. Whole system is monitored by programmable logic controller (PLC) which controls logicof the sensor outputs and also directs the motor used in solid waste separator. Interrupts in the form of alarm triggering and auto shut down plays vital role. The former engender an alarm in case of leakage overflow, while later becomes active in case of PID breakdown. Also reset switch acts as human interfacing operation. The system is analyzed in Lab VIEW and showed exceptional results. Design can be implemented in various industries beneficiating people in terms of chemical hazards, time, and efficiency by the complete automation of chemical plants.