Regenerable CuO-Based Adsorbents for Low Temperature Desulfurization Application

A series of CuO-based adsorbents for deep removal of H₂S at low temperature was prepared by a coprecipitation method. It was found that CuO-based adsorbents are able to remove H₂S from a CO₂ stream to less than 0.1 ppm at 40 °C. Among them, Fe–Cu–Al–O adsorbent exhibited the highest breakthrough capacity of 113.9 mg g^–1, which is more than 6 times that of pure CuO. The breakthrough capacity was also dependent on the adsorption temperature, space velocity, balance gas, and calcination temperature. The proper adsorption temperature should be lower than 100 °C in the presence of CO₂, and a higher space velocity and calcination temperature could decrease the breakthrough capacity significantly. In addition, the CuO-based adsorbents had a regeneration rate of 43–90% in air at a relative low temperature from 100 to 200 °C with a stable breakthrough capacity after four adsorption–regeneration cycles

Solubility and Characterization of CO₂ in 40 mass % <i>N</i>‑Ethylmonoethanolamine Solutions: Explorations for an Efficient Nonaqueous Solution

The CO₂ solubility in <i>N</i>-ethylmonoethanolamine (EMEA) solutions was investigated using the vapor–liquid equilibrium (VLE) and the absorption–desorption apparatus. A tertiary amine, <i>N</i>,<i>N</i>-diethylethanolamine (DEEA), was used as a novel solvent, and other nonaqueous solvents, diethylene glycol, triethylene glycol, benzyl alcohol, <i>n</i>-butyl alcohol and polyethylene glycol-200, were used for comparison. The EMEA + DEEA solution displayed a much higher CO₂ solubility than other nonaqueous solutions though lower than the EMEA + H₂O solution in the VLE experiment. However, the EMEA + DEEA solution exhibited a higher cyclic absorption capacity than EMEA + H₂O solution in the cyclic absorption–desorption experiment. The reaction mechanism of EMEA + DEEA + CO₂ was investigated by ¹³C NMR spectroscopy, which indicated that the nonaqueous solvent of DEEA participated in the chemical absorption of CO₂, and thus improved the CO₂ solubility. The tertiary amine DEEA used as a nonaqueous solvent shows more excellent performance than alcohols and glycols