Page 64 - 2024-Vol20-Issue2

60 | Al-Najari, Hen, Paw, & Marhoon

Fig. 1. PH sensor Fig. 2. PH transmitter

regulation in cooling towers is a very important job. Control-
ling of PH in neutral region is an important process as small
change in input gives the huge change in output [6]. System
identification toolbox of MTALAB is used to find the transfer
function of PH loop [7]. The PID controller parameters are
traditionally tuned through the Zeigler-Nichols method [8]. In
this paper, design and implementation of PID controller for
the cooling tower’s pH regulation based on Particle Swarm
Optimization PSO algorithm is proposed.

II. PH LOOP DEVICES OF COOLING TOWER

The PH loop consists of the devices below:

A. PH Sensor Fig. 3. Sulfuric acid pump
The PH sensor is installed in the process. It converts the PH
of cooling water to an electric signal. It is connected to the III. PH LOOP OF COOLING TOWER
PH transmitter. Fig. 1 shows the PH sensor. MODELING

B. PH Transmitter To design the controller for PH loop, the transfer function
The PH transmitter takes the electric signal from the PH sen- of the loop must be obtained. There are two methods for
sor and displays it on its screen. The PH reading appears on system modeling physical and data-driven methods. For com-
the transmitter screen. Fig. 2 shows the PH transmitter. plex systems, the associated physical equations and dynam-
ics are sometimes difficult to be constructed using domain
C. Sulfuric Acid Pump knowledge-based derivations. On the contrary, data-driven-
The water coming from the process and entering the cooling based modeling can skip this challenge providing the asso-
tower is alkaline. That means the PH is high. The sulfuric ciated input/output data are available [9]. Meng Chen pro-
acid pump is used to pump the sulfuric acid solution to the posed a data-driven speed control method which uses the least
cooling tower to reduce the PH of the cooling water. The square method to identify the precise mathematical model of
sulfuric acid pump is operated manually and irregularly by the system based on the input and output data of the controlled
operators. Fig. 3 shows the sulfuric acid solution pump. system in real-time [10]. A data-driven approach is used to