Comparative Study of Single-Tube and Spiral Tube Heat Exchangers in a Temperature Swing Adsorption System for CO₂ Capture

Abstract

Carbon capture using temperature swing adsorption (TSA) is a promising technology for mitigating CO₂ emissions. The thermal management of the adsorbent bed is critical to the energy efficiency and overall performance of the TSA process. This study presents a computational fluid dynamics (CFD) simulation in COMSOL Multiphysics to compare the performance of two internal heat exchanger designs within a packed bed of Zeolite 13X-APG: a conventional straight-tube heat exchanger and a novel spiral tube heat exchanger. A three-step TSA cycle (adsorption, desorption, cooling) was modelled to capture CO₂ from a representative flue gas stream (15% CO₂). The performance of each design was evaluated based on four key metrics: CO₂ purity, CO₂ recovery, specific energy consumption (SEC), and the coefficient of performance of CO₂ capture (COP_CO₂). The results indicate that the spiral tube heat exchanger provides more uniform heat distribution, leading to a higher CO₂ recovery of 68.1% compared to 60.1% for the straight-tube design, and a 12% reduction in specific energy consumption. These findings highlight the significant impact of heat exchanger geometry on the efficiency of TSA systems.