Modelling and simulation of intensified absorber for post-combustion CO₂ capture using different mass transfer correlations

This paper studied mass transfer in rotating packed bed (RPB) which has the potential to significantly reduce capital and operating costs in post-combustion CO₂capture. To model intensified absorber, mass transfer correlations were implemented in visual FORTRAN and then were dynamically linked with Aspen Plus® rate-based model. Therefore, this represents a newly developed model for intensified absorber using RPB. Two sets of mass transfer correlations were studied and compared through model validations. The second set of correlations performed better at the MEA concentrations tested as compared with the first set of correlations. For insights into the design and operation of intensified absorber, process analysis was carried out, which indicates: (a) With fixed RPB equipment size and fixed Lean MEA flow rate, CO₂ capture level decreases with increase in flue gas flow rate; (b) Higher lean MEA inlet temperature leads to higher CO₂ capture level. (c) At higher flue gas temperature (from 30 °C to 80 °C), the CO₂ capture level of the intensified absorber can be maintained. Compared with conventional absorber using packed columns, the insights obtained from this study are (1) Intensified absorber using rotating packed bed (RPB) improves mass transfer significantly. (2) Cooling duty cost can be saved since higher lean MEA temperature and/or higher flue gas temperature shows little or no effect on the performance of the RPB

Process analysis of intensified absorber for post-combustion CO₂ capture through modelling and simulation

Process intensification (PI) has the potential to significantly reduce capital and operating costs in postcombustion CO₂ capture using monoethanolamine (MEA) solvent for power plants. The intensified absorber using rotating packed bed (RPB) was modelled based on Aspen Plus® rate-based model, but some build-in correlations in Aspen Plus® rate-based model were replaced with new correlations suitable for RPB. These correlations reflect centrifugal acceleration which is present in RPB. The new correlations were implemented in visual FORTRAN as sub-routines and were dynamically linked to Aspen Plus® rate based model. The model for intensified absorber was validated using experimental data and showed good agreement. Process analysis carried out indicates: (a) CO₂ capture level increases with rotating speed. (b) Higher lean MEA inlet temperature leads to higher CO₂ capture level. (c) Increase in lean MEA concentration results in increase in CO₂ capture level. (d) Temperature bulge is not present in intensified absorber. Compared with conventional absorber using packed columns, the insights obtained from this study are (1) intensified absorber using RPB improves mass transfer significantly. (2) Higher flue gas temperature or lean MEA temperature will not be detrimental to the reactive separation as such cooling duty for flue gas can be saved. (3) Inter-cooling cost will not be incurred since there is no temperature bulge. A detail comparison between conventional absorber and intensified absorber using RPB was carried out and absorber volume reduction factor of 12 times was found. These insights can be useful for design and operation of intensified absorber for CO₂ capture

Preliminary Performance Assessment of Intensified Stripper in Post-combustion Carbon Capture through Modelling and Simulation

Intensified stripper used in chemical absorption process based on rotating packed bed (RPB) technology was studied through modelling and simulation in this paper. The model was developed by dynamically linking Aspen Plus® ratebased model with visual Fortran. Suitable correlations for RPB were implemented in Fortran to replace the default correlations in Aspen Plus® rate-based model. The standalone stripper model was validated with experimental data. The paper compared standalone intensified stripper with conventional stripper using MEA solvent. The result shows 9.69 times size reduction. Therefore PI has great potential for use in carbon capture application

Process intensification for post combustion CO₂ capture with chemical absorption: a critical review

The concentration of CO₂ in the atmosphere is increasing rapidly. CO₂ emissions may have an impact on global climate change. Effective CO₂ emission abatement strategies such as carbon capture and storage (CCS) are required to combat this trend. Compared with pre-combustion carbon capture and oxy-fuel carbon capture approaches, post-combustion CO₂ capture (PCC) using solvent process is one of the most mature carbon capture technologies. There are two main barriers for the PCC process using solvent to be commercially deployed: (a) high capital cost; (b) high thermal efficiency penalty due to solvent regeneration. Applying process intensification (PI) technology into PCC with solvent process has the potential to significantly reduce capital costs compared with conventional technology using packed columns. This paper intends to evaluate different PI technologies for their suitability in PCC process. The study shows that rotating packed bed (RPB) absorber/stripper has attracted much interest due to its high mass transfer capability. Currently experimental studies on CO₂ capture using RPB are based on standalone absorber or stripper. Therefore a schematic process flow diagram of intensified PCC process is proposed so as to motivate other researches for possible optimal design, operation and control. To intensify heat transfer in reboiler, spinning disc technology is recommended. To replace cross heat exchanger in conventional PCC (with packed column) process, printed circuit heat exchanger will be preferred. Solvent selection for conventional PCC process has been studied extensively. However, it needs more studies for solvent selection in intensified PCC process. The authors also predicted research challenges in intensified PCC process and potential new breakthrough from different aspects