Process simulation for electronic-grade methanethiol synthesis via H

This study proposes an integrated process for producing electronic-grade methanethiol (EMT) from H2S-rich Rectisol tail gas (RTS) through three stages: H2S purification, methanethiol (MT) synthesis, and MT refining. First, a two-stage methyl diethanolamine absorption-desorption process selectively recovers H2S from RTS, achieving 92 mol% H2S purity. Subsequently, MT is synthesized via methanol and H2S over a K2WO4/Al2O3 catalyst in a fixed-bed reactor optimized at 380°C, 10 bar, and a mass hourly space velocity (MHSV) of 2 h−1, achieving 90% methanol conversion and 92% MT selectivity. Finally, the crude product is separated via a optimized distillation sequence, with a pressure-swing distillation to break the methanol-dimethyl sulfide azeotrope, yielding EMT with 99.99 wt% purity. Rigorous Aspen Plus simulations demonstrate the process's economic viability, leveraging H2S valorization to produce high-value EMT while meeting stringent emission standards (<0.03 mg/m3 H2S).