Experimental investigation of the separation of oxygen and nitrogen from air employing pressure swing adsorption process

• Main Author: Chng, Gordon Yu Qing
• Other Authors: Anutosh Chakraborty
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/167552
• Institution: Nanyang Technological University

Employing the pressure swing adsorption test facility, the proposed final year project (FYP) report seeks to address the gas separation phenomena employing adsorption technology. The adsorption-based gas separation technique is used for food storage, air ventilation and purification application. Therefore, the main goal of the study is to separate O2 and N2 from air and calculate the amount of oxygen purity. The O2 purity is evaluated for various operating conditions ranging from adsorption desorption cycle time to air flow rates. During experiments, several valves are connected to a PLC-CPU such as Siemens SIMATIC S7-200 via a PLC Ladder Program employing highly accurate timers to control the experimental setup. The proposed arrangement aids in automating the entire oxygen production, which makes it capable of running after the times are inputted without any more external control. To adsorb carbon dioxide, nitrogen, and water vapour, respectively, molecular sieves made of silica gel, zeolite JLOX-101, and 13X are employed in the experimental setup. The experimental set up namely pressure swing adsorption (PSA) is affected by adsorption time, the pressure of the feed gas, pressurisation time, feed flow rate, and purge flow rate. In order to achieve the highest possible oxygen purity, these variables are carefully examined and tested. The programmable ladder diagram is used to control the overall system. Secondly the needle valve controls the air flow rate. The combination of ladder control plus needle valve improves the performance of PSA in terms of oxygen purity. The experimental conditions consist of a 2 second adsorption period, a feed gas pressure of 2 bar entering the adsorption bed, a pressurisation time of 0.2s, a feed flow rate entering the adsorption bed at 45, and a purge flow rate of 5 l/min. The results show that the PSA device with two bed adsorption columns provides the oxygen purity up to 87%. However, the O2 purity can be improved by considering four bed adsorption columns.