| With the increasing energy demand in world, coal and oil consumption will gradually decline. Natural gas will become the world’s first energy, and natural gas is high quality and efficient clean energy, its use will be more aroused great concern to all countries. Carbonyl sulfide is an acid gas that is present in natural gas. This sulfur species is corrosive to pipelines and other processing equipment, and poison the catalyst in the production process. It is also toxic, and the removal of these components down to very low concentrations is often required. However, carbonyl sulfide is difficult to be removed because of its low solubility in aqueous solutions and slow hydrolysis to H2 S. Thus, it is practically significant to develop a better technology to remove it. SO2 in the flue gas after combustion will also cause environmental pollution and endanger human health. So find effective SO2 removal and recycling technology has become essential.In this paper, the SO2 absorption mechanism in PEG and the COS absorption mechanism in EG were studied. Gas-liquid equilibrium(GLE), physicochemical properties and spectroscopic studies were performed to study the SO2 absorption mechanism in PEG and the COS absorption mechanism in EG. All the experiments are divided into three parts:(1) The absorption amounts of COS in EG-H2 O was determined at different concentration, temperature. And GLE data of SO2 in PEG-H2 O was determined at different concentration, temperature, and pressure conditions, and Henry constants(HLC), enthalpy(–ΔΗH) and entropy(–ΔSH) values were fitted.(2) Density and viscosity were determined over the whole concentration range of PEG-H2 O at temperatures range of T =(298.15 ~ 318.15) K. The excess mole volume(Vm E) was obtained as a further study.(3) Ultraviolet(UV), fluorescence(FL), infrared(IR), and nuclear magnetic resonance(1H-NMR) spectral changes of EG-H2 O, EG-H2O+COS, PEG-H2 O, PEG + SO2, and PEG-H2 O + SO2 were studied.Conclusions can be drawn that the absorption ability of EG-H2 O arrived maximum value at the volume fraction EG of 0.50 and the temperature of 40℃. The absorption ability of PEG-H2 O decreased to a minimum and then increased with the increasing PEG concentration. Minimum value of 2.38 mol·m-3 was confirmed at the mass fraction PEG of 0.50 and maximum value of 4.23 mol·m-3 was arrived at the mass fraction PEG of 0.05 respectively. The absorption ability decreased with the increasing temperature but increased with the increasing of molar polymerization degree, while the little changes of pressure has nearly no influence. What is more, the absorption ability of PEG-H2 O can be strengthened by adding small quantity of Nd(NO3)3. The Vm E values were calculated, which presented negative for the whole concentrations suggested the interactions between PEG and H2 O, and connected most tightly when the molar concentration of PEG at 0.20. The interaction of PEG and H2 O can provide more binding sites for SO2.Spectroscopic results suggested that the absorption mechanism of SO2 in PEG is attributed to intermolecular hydrogen bonding between PEG and SO2 as the formation of-CH2-(CH2OCH2)n-CH2OH···OSO···and intermolecular S···O ineraction as the formations of-CH2CH2OCH2CH2O(H) ···(O)SO··· and-CH2-CH2-O(CH2-CH2-)···(O)SO···. And COS can interact with EG by hydrogen bonds as ···HO-CH2CH2O-H···OCS. |
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