The Reinforcement Of CO₂ Capture In Non-aqueous Absorbent With Solid Materials

CO₂ from the fossil fuels is the main contributor to the greenhouse effect,which has triggered a variety of environmental problems in recent years,and thus the CO₂ capture,utilization,and storage?CCUS?have attracted enormous attention around the world.There are lots of CO₂ capture technologies,such as physical absorption,chemical absorption,adsorption,membrane separation and so on.In CO₂ capture,post-combustion CO₂ capture using chemical absorption methods,particularly aqueous alkanolamine solutions,is considered as a rather mature and feasible technology in the application of industry due to its high CO₂ loading,fast reaction kinetics,and good cyclic performance.Among them,N-ethylethanolamine?EMEA?and N,N-diethylethanolamine?DEEA?have advantages such as fast regeneration rate,low regeneration energy consumption,and good thermal stability among non-aqueous absorbents.The paper mainly focused on improving the CO₂ capture.The research was designed due to the good mass and thermal transfer of nanofluids and the excellent catalytic properties of transition metal oxides.Therefore,the effects of non-metallic porous materials and transition metal oxides on 30 wt%EMEA+70 wt%DEEA were investigated in CO₂ capture.The CO₂ absorption/desorption performance and the stabilities of non-aqueous absorbents and porous materials were studied in non-aqueous absorbent with non-metallic porous materials.Its results show that,although the addition of non-metallic porous materials slightly reduced the CO₂ absorption loading,it had no effect on the CO₂ absorption rate,and it also increased the CO₂ desorption loading and desorption rate.Moreover,the types?multi-walled carbon nanotubes/MWCNTs,silica gel/SG and MCM-41?and loadings?0.025,0.050,0.100 and 0.200?g had different influences on the CO₂ absorption and desorption processes.The desorption enhancement factor results show that all the desorption enhancement factors reached the maximum value at 0.050 g,among which,the enhancement of 0.050 g MWCNTs was best.The results from the absorption-desorption cyclic experiments,XRD,FT-IR,N₂ physical adsorption and SEM characterizations show that 30 wt%EMEA+70 wt%DEEA+0.050 g MWCNTs and MWCNTs had good stability.The paper also researched the effects of transition metal oxides on the CO₂ absorption and desorption performance,the stability of absorbents and the possible desorption mechanism.The addition of transition metal oxides had little effect on the CO₂ absorption process,while promoting CO₂desorption process.The desorption enhancement factor results find that the desorption temperatures?363,373,and 383?K and the types of transition metal oxides?TiO₂,MoO₃,and Nb₂O₅?had different effects on the CO₂ desorption process,and MoO₃ at 373 K was the optimal desorption choice.The study of 30 wt%EMEA+70 wt%DEEA+Mo O₃ demonstrates that MoO₃ at?0.050,0.200,0.500,1.000 and 2.000?g increased CO₂ desorption loading and rate at the desorption temperature of 373 K.And absorption-desorption experiments show the good stability of 30 wt%EMEA+70 wt%DEEA+0.020 g MoO₃.The ¹HNMR and FT-IR characterizations show that EMEA and DEEA reacted with MoO₃.The protons provided by MoO₃ and its strong electronegativity promoted the carbamate breakdown and reduced the bond energy of C-N,which improved the CO₂ desorption process.