COMPARATIVE EVALUATION OF PROCESS CONTROL PERFORMANCE OF HOT OIL HEATING PROCESS USING TWO SERIAL OR PARALLEL HEAT EXCHANGERS

• Main Author: Khairunnisa Rustam M, Fikra
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/67365
• Institution: Institut Teknologi Bandung

Heat exchanger, a common system used in the industry to transfer heat from two or more fluids, a fluid play role as process fluid to undergoes cooling or heating and another fluid known as utilities utilized for cooling and heating. Some process in chemical plants requires big load and some have its pressure limits, high process heat duty requires more than one heat exchanger due to the unavailability of heat exchanger dimension that can attain such load. There have been various studies for control configurations for single heat exchanger but insufficient studies for double heat exchangers that uses hot oil as its heating medium as well. Therefore, there is a need to perform research on evaluation of process control performance on double heat exchangers. The study was done by performing a dynamic simulation using Aspen HYSYS v11 software on double heat exchangers with serial and parallel arrangement. Variations include control configuration, type of disturbance and tuning parameters. The performance of each variation is evaluated using process control performance criteria such as Ziegler-Nichols, Cohen-Coon, IAE, ISE, and ITAE. In this experiment, synthetic organic (Dowtherm-Q) is used as hot oil heating medium, and unstablized naphtha (hydrocarbon fluid) at temperature and pressure of 65.56?C and 758.5 kPa, respectively. The result of this comparative study shows that serial arrangement of double heat exchangers has higher heat transfer efficiency compared to parallel. Additionally, parallel configuration requires more control systems with an additional flow control for the split flows. Control configuration with valve on heating medium inlet with Cohen-Coon tuning method shows more stable and faster temperature control for both serial and parallel compared to control valve on heating medium outlet. Serial arrangement results in lower integral of error criteria and lower overshoot, at 0.157 and 3.5% respectively, compared to parallel arrangement. However, parallel arrangement results is a little faster settling time but with higher overshoot up to more than 11%.