Parametric Analysis of a Moving Bed Temperature Swing Adsorption (MBTSA) Process for Postcombustion CO₂ Capture

Abstract

We simulate a moving bed temperature swing adsorption (MBTSA) process to capture CO2 in postcombustion context using zeolite 13X as adsorbent. Experimental adsorption isotherms for CO2 and N2 were performed gravimetrically to obtain the equilibrium input data for the model. The need of the flue gas drying was demonstrated by pure water and binary water/CO2 experimental adsorption isotherms, and the energy penalty of the water removal was accounted for within the energetic duty of the unit. The model consists of three sections (adsorption, regeneration, and cooling) each with its own model and integrated by a composite model that simulates the entire unit. Given the large number of variables and parameters in a MBTSA process, which can be arranged in different input data sets, a parametric study of the effect of several variables (feed gas flow rate, regeneration temperature, adsorbent residence time in the adsorption section, feed temperature, solid loading) on the key performance parameters of the process was performed. The results showed that, under the studied conditions, values up to 99% and 91% mol of CO2 recovery and purity could be achieved, respectively. The specific energy consumption, which included an energy recovery in the cooling section, was found to be competitive against reported values for commercial amine absorption separation processes suggesting that the MBTSA process might be a potential separation process candidate for large-scale postcombustion CO2 capture by adsorption.

Comparison of Designs of Hydrogen Isotope Separation Columns by Numerical Modeling

“…Thinner tubing walls could provide an efficiency advantage, but the tubing serves important safety and reliability functions. A true moving-bed arrangement, where the absorbing material moves through the tubing, has been considered to solve this problem in a different context . A configuration that minimizes the number of cycles needed to achieve a desired purity is likely to be the most energy efficient.…”

“…The valves on the bottom connect the columns, while the valves on the top are closed, so in two cycles, gas flows around the circle. The approach bears a resemblance to methods proposed for CO 2 capture. , …”

“…The approach bears a resemblance to methods proposed for CO 2 capture. 19,20 When operated as a closed system with a fixed charge of gas ("total reflux" mode), the SMB design has potential advantages over TCAP. By flowing gas in a circular path, it avoids stagnant endpoints where minimal separation can occur and avoids remixing of isotopes upon changes in the flow direction.…”

Gas-Particle Flows in a Two-Stage Integrated Bubbling-Transport Fluidized Bed for CO2 Capture

“…Postcombustion CO 2 capture refers to capturing carbon dioxide (CO 2 ) from flue gases generated after combusting carbon-based fuels. It is one of the most promising technologies for carbon capture and storage (CCS). − By comparing with other technical routes of postcombustion CO 2 capture, the chemical adsorption process using low-temperature solid sorbents (i.e., alkali-based sorbents and solid amine sorbents − ) has gained great attention owing to the advantages of the low additional energy demand, lack of corrosion, and low secondary pollution …”