Effect of promoters L-Met and MWCNT on formation of CO2 hydrate under multiple-pressurizing conditions
Since the industrial revolution,greenhouse gas emissions have been increasing along with wide fossil fuels applications,which leads to significant global climate change and then a commonly-concerned subject focused by international researchers and governments.Because the main component of greenhouse gas is CO2,some novel technologies for CO2 capture and separation from flue gas have been widely studied during recent years,among which the hydrate method is an emerging one.However,the outstanding problem during its applications is how to obtain a faster rate and higher amount of hydrate formations.Rapid CO2 hydrate formation requires high-pressure gas conditions,but along with continuous hydrate formations,gas pressure in reaction system will continue declining.The initial pressure recovery of reaction system by multi-pressurizing is therefore a general method.In this study,two typical kinetic accelerators,L-methionine(L-Met)and multi-walled carbon nanotubes(MWCNT),were selected.And the kinetic promotion effects of them on formations of carbon dioxide hydrate were then compared under repeated recoveries of initial pressure conditions.The experimental results showed that when the initial pressure was repeatedly restored,MWCNT and L-Met system both significantly reduced the induced time of hydrate nucleating processes.L-Met with 1.1g/L concentration could significantly promote formation of carbon dioxide hydrates,and the formation amount of hydrate was 5 times that in pure water system.The hydrate formation rate in L-Met system was higher than that in MWCNT system.The conversion rate of gas in 1.1g/L L-Met system was the highest 70.3%,being 6 times that in pure water system.According to the final experimental results,L-Met was more superior than MWCNT as a carbon dioxide hydrate kinetic accelerator.It could be then used as an efficient,reliable and environmentally friendly kinetic accelerator during the large-scale application of hydrate-based technologies for CO2 capture and separation from flue gas.
carbon dioxide hydratemultiple-pressurizingL-methionine(L-Met)multi-walled carbon nanotubes(MWCNT)characteristics of formation reaction
国家科技期刊平台
NSTL
万方数据
