Effect of preparation method of active component on the cycling performance of sorbents for hot coal gas clean‐up

High temperature gas desulphurization is an efficient environmentally friendly process for high efficiency technologies with syngas clean-up. The present study investigated the impact of preparation methods on the behaviours of ZnO/red clay sorbent. The sorbents were prepared by the homogeneous precipitation method and solid-state method, respectively. The surface and structural properties of the sorbents were characterized by thermogravimetric, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope-elemental mapping, and N-2 adsorption analysis. Successive desulphurization-regeneration cycles were conducted to investigate the reusability of the sorbents. After four cycles of desulphurization-regeneration experiments, the breakthrough times of the two kinds of regenerated sorbents plunged 18.17% and 23.26%, respectively. Attritions of sorbents have not been observed, meaning the regenerated sorbents still maintain a high mechanical strength. The sorbents prepared through the homogeneous precipitation method were found to exhibit a longer breakthrough time much greater than those prepared by the solid-state method. The characterization data indicate that the homogeneous precipitation method results in more uniform distribution of active component sorbent with smaller particle size and better pore structure, which favours the chemical reaction and mass transfer processes.