Research On Carbon Capture Using Nanoparticle-Organic Amine Hybrid Absorbent

Carbon dioxide（CO₂）in the flue gas after combustion can usually be captured by ethanolamine solutions such as monoethanolamine（MEA）,diethanolamine（DEA）,N-methyldiethanolamine（MDEA）and their mixed amine solutions as absorbents.Such absorbents have the advantages of large absorption capacity and fast reaction rate.However,the regeneration temperature and energy consumption are high,and the corrosion to the equipment is serious..Adding nanoparticles to the traditional alkanolamine solution to form nanofluids is an effective way to solve the current problems of carbon capture.Nanofluids are fluids produced by dispersing nanoparticles directly into a base fluid..Due to its enhanced heat transfer performance,higher thermal conductivity,and stronger convective heat transfer coefficient,nanofluids can provide new ideas for carbon capture with mixed absorbents.In this thesis,methyldiethanolamine（MDEA）was used as the main absorbent,and nanoscale TiO₂,nanoscale SiO₂ and GO were used as accelerators to construct a new compound alcoholamine system.By changing the particle size of nanoparticles and the mass fraction of nanoparticles,the absorption capacity,absorption rate and circulating desorption capacity of alkanolamine aqueous solution were investigated,and the ratio of compound alkanolamine absorption liquid with superior capture performance was determined.In addition,the viscosity,surface tension and liquid density of the absorption liquid were investigated to provide a reference for the design simulation of absorption towers and process design and simulation involving enhanced mass transfer in actual production operations.The intermediate and final products of the reaction were analyzed by Fourier transform infrared（FT-IR）and carbon-13 nuclear magnetic resonance(¹³C NMR)characterization methods,and the mechanism of CO₂ capture by the complex alkanolamine system was explored.The results showed that the absorbents composing of30wt%MDEA-0.05wt%TiO₂（40nm）and 30wt%MDEA-0.05wt%SiO₂（15nm）are effective and optimal in terms of CO₂ absorption rate and amount.Under the experimental condition of 30℃,the viscosity and surface tension of the CO₂-rich solution after absorption are smaller than those of the blank group,yet the density value is greater than that of the blank group.Under the experimental condition of 40℃,the particle size and density of nanoparticles are inversely proportional.Under the experimental condition of 50℃,the viscosity value of the CO₂-rich sample containing nanoparticles is greater than that of the blank group,and the surface tension value is inversely proportional to the mass fraction of SiO₂.The characterization by Fourier transform infrared（FT-IR）and carbon-13 nuclear magnetic resonance(¹³C NMR)showed that the addition of nanoparticles improved the gas-liquid mass transfer without generating new species.