Troubleshooting of an Industrial Ethane Treatment Unit: Ultradilute CO₂ Adsorption from Ethane Stream by a Temperature Swing Adsorption Process

This study introduces a model-based approach to troubleshoot an industrial ethane treatment unit (ETU) employing a two-bed temperature swing adsorption (TSA) process with zeolite 5A to reduce the CO2 impurity in the ethane stream to less than 50 ppm. Despite meeting ethylene feedstock specifications, the ETU faced challenges, such as low CO2 break time, reduced hydrocarbon recovery, and ethane productivity. The study diagnosed the entire process, including the adsorbent and original design, and experimentally measured new equilibrium data for CO2 and C2H6 on zeolite 5A. The primary factors contributing to the decreased CO2 break time and ethane productivity were identified as the omission of ethane adsorption in the original design and the prolonged heating duration. By refining the model and adjusting the feed temperature and heating duration, the study achieved significant improvements: an 111.9% increase in ethane productivity, a 12.9% higher hydrocarbon recovery, a 29.5% reduction in average CO2 impurity, and a 10.5% decrease in specific energy consumption.