The case study is on the control loops that are found in conventional drinking water treatment facilities.
engineering
Description
Study on Process Identification and Controller Tuning
Loop 1: Post-Lime Dosing
The case study is on the control loops that are found in conventional drinking water treatment facilities. The main objective is to propose a systematic approach to tune the PID controller settings, especially to enable quality-based control. The SCADA system has been used to log some of significant data for this case study such as time, pH, flow rate and etc.
Figure 1
Fig. 1 shows the location where lime is added to the water post treatment. The water parameter such as pH must be regulated in range of 6.5 to 8.0. This is done by dosing lime slurry at the overflow weir between CC and CW. The water flow in the tank will help the lime particle to disperse and dissolve water. The exact dosage flow depends strongly on the nature of the source water and typically it is provided in the dataset (129 views/downloads).
In this project, empirical model relations must be established from open-loop data and it must be fitted to a first order with dead time transfer function. This step is typical in process system engineering where most process has correlation between input and output of certain control system. The dead time is either an approximation of large time constant of processes or a result of transport lag in the measurement.
In controller design for empirical tuning relations, such as Cohen and Coon is most favourable for disturbance cases where it able to achieve a one quarter of decay ratio. However, it tend to be very oscillatory and underdamped for servo problem.
Project Deliverable
- Each group must submit an infographic media (A1 size).
- Only ONE submission is allowed per group with limited number of words (MAX: 30 words).
- An illustration and content must include: objective, proposal methodology, result, discussion and conclusion.
