CO2 capture and separation from flue gas by spraying hydrate method

Capturing CO2released from large point sources such as power plants is an option to reduce man-made CO2emissions. As a new gas separation and purification technology, the hydrate method is key to strengthening the formation rate and water-to-hydrate ratio. In this study, a self-developed spray hydrate reactor was used to carry out carbon capture experiments with large and small water volumes (640 and 160 ml). And the carbon capture efficiency and hydrate growth characteristics were investigated under the nozzle aperture diameters of 0.1 and 0.8 mm, and different concentrations of kinetic promoters: sodium dodecyl sulfate (SDS) and L-methionine (L-Met). The experimental results show that the 0.1 mm aperture nozzle is favorable for CO2 capture. For both L-Met and SDS systems, the final amount of CO2 gas trapped in per mole of solution is an order of magnitude higher than that in pure water, and the efficiency of the promoter is better at a lower concentration 0.1% (mass) than that at a higher concentration 1% (mass). The final gas consumption of the SDS system in the large water volume experiment is the highest at 0.0848 mol /mol H2O, 1.4 times that of the L-Met system, but the capture rate of the L-Met system is better than that of the SDS system. In the small water volume experiment, the gas capture amount and capture rate of the L-Met system are better than that of the SDS system. The growth angle of hydrate wall-climbing is 1.8 times that of 1% (mass) at 0.1% (mass) promoter. Such combination of L-Met solution with concentration 0.1% (mass), a nozzle with aperture 0.1 mm, and an injection method with small rate 3.33 ml/min, represents the best performance of promoting hydrate-based CO2 capture. The results provide reference and basic experimental data for the enhancement of CO2 capture in flue gas by hydrate method in spray reactor. © 2024 Materials China. All rights reserved.