Carbon dioxide hydrate separation from Integrated Gasification Combined Cycle (IGCC) syngas by a novel hydrate heat-mass coupling method

Abstract

A novel hydrate heat-mass coupling separation (HHMCS) method was studied to reduce the energy consumption of CO2 hydrate separation from Integrated Gasification Combined Cycle (IGCC) syngas in this work. Tetra-n-butyl ammonium bromide (TBAB) is used as a hydrate promoter and pure TBAB hydrate is used as a phase change heat-mass coupling additive. The heat-mass coupling effect, CO2 separation characteristics and influence factors were studied by continuous separation experiments in a bubble column reactor. Compared to conventional gas hydrate separation method, the HHMCS process exhibits a higher energy-saving potential, less temperature and TBAB concentration fluctuation due to pure TBAB hydrate phase change. Increase inlet gas rate, the accumulated gas consumption decreased slightly, but the average gas consumption rate increased. Increase operating pressure and decrease gas phase volume increased the average gas consumption rate and CO2 separation efficiency. After continuous separation of simulated syngas, the average CO2 concentration in H2-rich gas decreased to 17.45 mol%, and that in CO2-rich gas increased to 86.44 mol%. The CO2 split fraction and separation factor reached 0.80 and 8.15, respectively. The work provided a new idea to integrally utilize the phase change enthalpy, improve the operating flexibility and heat transfer in large device.