Study on the desulfurization performance of hydramine/ionic liquid solutions at room temperature and atmospheric pressure

- A new green process for gas desulfurization has been developed.
- The desulfurizers were prepared by dissolving hydramine into ionic liquids.
- The H2S removal efficiency could reach nearly 100% for 2 h.
- The ethanolamine/ethanolamine lactate solution can be recycled perfectly.
- Compared with aqueous solution, the operation of desulfurizer is more stable.

Seven hydroxyl ammonium ionic liquids were synthesized by neutralization reaction and characterized by Fourier transform infrared spectroscopy, elemental analysis, 1H Nuclear Magnetic Resonance and Electrospray ionization mass spectrometry. To enhance the desulfurization performance of the pure ionic liquids which showed weak physical and chemical absorption for H2S, seven hydramine/ionic liquid solutions were prepared by dissolving hydramine in ionic liquids with corresponding cations: ethanolamine/ethanolamine acetate, ethanolamine/ethanolamine formate, ethanolamine/ethanolamine propionate, ethanolamine/ethanolamine lactate, diethanolamine/diethanolamine acetate, triethanolamine/triethanolamine acetate and N-methyl diethanolamine/N-methyl diethanolamine acetate. And their desulfurization performances were investigated through dynamic H2S absorption experiment. The solution of ethanolamine/ethanolamine lactate shows the best desulfurization capacity, and the H2S removal efficiency can reach nearly 100% for 2 h. The results show that lower temperature and H2S concentration were beneficial to the H2S absorption reaction. The absorbent recovery experiment shows that ethanolamine/ethanolamine lactate solution can be recycled perfectly. The saturated sulfur capacity and reaction characteristics of absorption were discussed by mathematical calculation. The mass loss and foaming rates of IL solution and aqueous solution were compared, and the results showed that the operation of hydramine/ionic liquid solution was more stable. These results indicate that hydramine/ionic liquid solutions have a potential utilization value for H2S removal.

The hydramine/ionic liquid solutions were prepared by dissolving hydramine in hydroxyl ammonium ionic liquids with corresponding cations. The solution of ethanolamine/ethanolamine lactate shows a best desulfurization capacity with a H2S removal efficiency of nearly 100% for 2 h.86