IL-Emitsol: Ionic Liquid Based [EMIM][Tf₂N] Solvent Process for Selective Removal of CO₂ and H₂S from Syngas

Abstract

For the first time, a practical ionic liquid (IL) based acid gas removal (AGR) process for selective removal of CO2 and H2S from syngas was designed, simulated, and optimized in this work. The popular UNIFAC property model, the parameters of which derived from experimental data, was used in the simulation. The newly developed process, named IL-Emitsol, utilizes the [EMIM][Tf2N] solvent and yields three product streams as (1) a clean syngas with 0.27 mol % CO2 and less than 100 ppb H2S, (2) a CO2 stream with 96.68% CO2 capture level (CO2CL) and 99.37 mol % purity with less than 100 ppm H2S, and (3) a H2S stream containing 63.66 mol % H2S. In comparison with the benchmark Rectisol process, the IL-Emitsol process is more efficient in terms of clean syngas production, CO2 capture and production, H2S production, solvent loss, and electricity consumption. However, it requires more than 4 times higher direct capital investment, although it is indeed a typical chemical process intensification technology.