Response surface modelling ofCO2capture by ammonia aqueous solution in a microchannel

Post-combustion CO(2)capture is one strategy of greenhouse gases mitigation. Ammonia is a useful option as CO(2)absorbent and an alternative to conventional amine-based solutions. This study deals with CO(2)capture by ammonia aqueous solution in a co-current two-phase flow by utilizing a T-shaped microchannel. Three parameters of temperature, gas flow rate, and ammonia concentration were considered as the main parameters affecting the CO(2)capture efficiency. A response surface methodology based on central composite design (CCD) was used to model the CO(2)capture efficiency as output in terms of the aforementioned input variables. CCD suggested a quadratic model to fit the experimental data. The model validation was implemented by ANOVA. All statistic tools including correlation coefficient,P-value, and F-value of the model, andP-value of lack-of-fit confirmed that the prediction model was significant. It was deduced from F-values that the importance of the input variables followed the sequence of ammonia concentration > gas flow rate > temperature. Ammonia concentration was the most effective input variable because there was a direct correlation between ammonia concentration and the number of absorption sites in the liquid phase. Numerical optimization predicted the best output of 96.48% CO(2)capture under the following optimum conditions: temperature of 20.00 degrees C, gas flow rate of 110.59 mL/min, and ammonia concentration of 0.1382 mL/mL (13.82 vol%). The average CO(2)capture of 95.42% obtained at the input conditions indicates the accuracy of the prediction model.

Automated summary

The study focused on CO(2) capture using ammonia aqueous solution in a T-shaped microchannel, with ammonia concentration being the most influential parameter followed by gas flow rate and temperature. Numerical optimization predicted the highest CO(2) capture efficiency under optimal conditions, with ammonia concentration having the greatest impact. This suggests that optimizing ammonia concentration is crucial for achieving higher CO(2) capture efficiency.