Analysis of pilot scale packed absorption towers for hydrogen sulphide removal from syngas by model simulations and experimental data

A 1 MWth pilot plant was operated for syngas and liquid fuels production from low calorific value (2,000-2,500 kcal/kg) lignites. The coal feedstock utilised had relatively high sulphur content (approx. 2.5 %) that was mainly converted to hydrogen sulphide (H2S) by gasification process. Structured packed absorption columns were designed and utilised with main performance target of H2S outlet concentration (less than 1 ppmv) with minimum caustic utilisation. H2S removal targets were reached as 0.2-0.5 ppm(v ) range at the outlet of the second column. Recent rate-based modelling approach was preferred for columns since it was evaluated as more representative than traditional equilibrium-stage modelling method. Gas phase, liquid phase, overall mass transfer coefficients and enhancement factors were analysed for different pilot plant operation parameters. It was found that simulation results by 'Hanley's model' for mass transfer calculations suited better to our experimental data when other empirical models were considered. [Received: May 19, 2021; Accepted: December 25, 2021]