Energy Requirements to Capture and Liquefy Isobutane in an Electrothermal Swing Adsorption System

摘要

A bench-scale system was developed to capture, recover, and condense low concentration organic gases using activated carbon fiber cloth (ACFC) and electrothermal desorption with post-desorption liquefaction using compression and cooling. This gas recovery system (GRS) will improve the economics of industrial processes that emit low concentration organic gases that could be reused if they were captured and recovered rather than thermally oxidized. The energy required to capture and condense organic gases is of interest so that comparisons to traditional abatement techniques (e.g., thermal oxidation) can be made. Previously, the energy per mol of adsorbate captured was determined for the GRS, however examining the energy per mol of liquid adsorbate recovered is a more realistic measure of the GRS performance. To determine the energy requirements of the GRS, isobutane was used as the model adsorbate. The energy required to recover liquid isobutane was determined for several heating and compression times ranging from 3-9 min. Results showed that a minimum in the amount of energy required to recover liquid isobutane occurs at moderate heating/compression times (5-7 min). This minimum is the result of the balance between adequately desorbing the adsorbed gas and diminishing returns on the amount of isobutane desorbed at longer heating times. The results obtained by this study will be used to compare the GRS to other abatement technologies and inform decisions about operating conditions for other adsorbates and for larger scale systems.