Research On The Modification Of Methanol As Solvet For Absobing Carbon Dioxide

In industrial production, it is often necessary to remove CO2 in synthesis gas, natural gas or fuel gas stream effectively.The physical absorption of methanol was modified to absorb CO2 by adding [OMIM][Tf2N] and ZIF-8 separately in this work. We mainly explores the gas liquid equilibrium of CO2 (1)+CH3OH (2)+[OMIM][Tf2N] (3) and CO2(1)+CH3OH (2)+ZIF-8 (3) system.The new group binary interaction parameters (amn and αnm) between CO2 and methanol/IL groups were obtained by correlating the solubility data collected from literature. We measured the gas liquid equilibrium data of CO2 +CH3OH, CO2+[OMIM][Tf2N] and CO2+CH3OH+[OMIM][Tf2N] and obtained the group binary interaction parameters between CO2 and the mixture of methanol and [OMIM][Tf>N] according the solubility data from this work. The results confirmed the strong predictive power of UNIFAC model for methanol-CO2 and methanol-IL-CO2 systems at low temperatures. It was also found that low temperature and high pressure could increase the CO2 solubility and the solubility follows the order of xw3=0.00<xw3=0.20<xw3=0.50< xw3=0.80<xw3=1.00, Henry’s constants of CO2 show the opposite order. The CO2 absorption and separation process was simulated using Aspen plus in this work and it shows that the addition of [OMIM][Tf2N] into methanol can not only reduce amount of methanol entrained but also decrease the the energy consumption and operating cost.This work mainly researched the method of bulk synthesis of ZIF-8 and carried out the bulk synthesis of ZIF-8 successfully on the basis of reference. The gas liquid equilibrium data of CO2 (1)+CH3OH (2) and CO2 (1)+ CH3OH (2)+ZIF-8 (3) (w3= 0.05,0.10,0.15) was measured and was predicted by the lever rule combining UNIFAC model and GCMC (grand canonical Monte Carlo) simulation together. The result showed that the lever rule combining UNIFAC with GCMC simulation can be applied to predict the gas dissolution equilibrium in adsorptive absorption.The experimental and predicted results showed that at low pressures the addition of ZIF-8 in methanol can increase the solubility of CO2; however, the enhancement at high pressures is not obvious. Noting that the volatile loss of methanol in gas phase can be significantly reduced using the mixed absorbent at whole pressure and temperature range. In principle, it is very easy to be implemented in practice using the methanol and ZIF mixture instead of traditional methanol.