Measurement And Modeling Of CO₂ Solubility In Dibutyl Ether And Its Complex Absorbents

Large amount of CO2 emitting from power station, steel, cement production, cement production, oil refinery and gas purification is the major contributor of global warming. There are mainly three scenarios for capturing CO2 from such industrial sourses, which are pre-combustion, post-combustion and oxy-fuel. They all in common use solvent absorption method to fix the CO2 out of gas mixtures. High-efficiency and low energy cost CO2 absorbents are in great need and being sought for by many researchers. In this paper, some study on new CO2 absorbents based on the pre-combustion syngas condition was done as follows:First, some key properties of dibutyl ether, MMEA were compared with those of industrial solvents. Both dibutyl ether and MMEA have relatively lower viscosity, smaller molecular weight and higher CO2 absorption ability.Based on isothermal synthetic method, a new apparatus for gas solubility measurement was built in our laboratory. To verify the reliability, CO2 solubilities in ethanol and NMP were measured. Experimental data derived were then compared with those of literatures, and the absolute relative deviations for both systems are around 1%.Then, CO2 solubility data in dibutyl ether were measured at the temperatures of 288.15K,298.15K,308.15K,318.15K and 328.15K. SRK equation of state was used to correlate the data. SRK ky as a function of temperature was also obtained. The average absolute deviation between experimental pressure values and SRK calculated ones is 0.040MPa, and the average absolute relative deviation (AARD) is 2.96%.At last, CO2 solubility data were measured in 15.1%,25.0% and 49.5%(mass fraction) MMEA dibutyl ether complex absorbents at 298.15K. CO2 solubility data in 25.0% MMEA dibutyl ether solution were also measured at 308.15K,318.15K and 328.15K. It shows that CO2 is more soluble in complex solvents than in dibutyl ether at every MMEA concentration. Solubility increases with MMEA concentration. At lower pressure range, chemical absorption plays a leading part. When pressure goes up physical absorption begins to take over.