Dual-piston pressure swing adsorption system: Instrumentation and characterisation with pure gas experiments

Abstract

Dual Piston-Pressure Swing Adsorption systems offer the potential for rapid testing of novel adsorbent materials under a wide range of operating conditions. This characterisation of the properties of adsorbents is crucial for the development of efficient adsorption based separation processes. Here the instrumentation and characterisation of a semi-automated DP-PSA system as well as a mathematical model for the analysis of the experiments are presented. In this system each piston is independently controlled by a real-time computer which allows the autonomous running of a series of experiment with different cycle times, compression ratios and flow conditions. The real-time computer also handles the data acquisition from the pressure transducers (absolute and differential) and thermocouples which are placed inside the column. The entire system is enclosed in an oven to control the surrounding temperature and to enable experiments at different temperatures (20–200 °C). The small amount of solid material (5–10 g) together with the possibility of fast cycle times (down to 1 Hz) allow the rapid testing of the material under a large number of different conditions. The DP-PSA is demonstrated with two series of experiments: first, empty column experiments showed that the system has a low leak rate and negligible flow resistance between the pistons and column; second, experiments with the column packed with zeolite 13X pellets to validate the mathematical model and to demonstrate the experimental procedure for pure components.