Crystal growth mechanism in hydrothermal synthesis of zinc-manganese based desulfurization sorbent

WU Shuaishan; SUN Yangjie; NIU Fangfang; WANG Jiancheng; MI Jie; FENG Yu

doi:10.13226/j.issn.1006-6772.24010504

Abstract：Medium and high temperature gas desulfurization is one of the key technologies to realize the clean and efficient utilization of coal.The mechanism of sulfide growth and diffusion in the kinetics of metal oxide desulfurization reaction indicates that keeping the active component of desulfurization sorbent with high dispersion and small size is beneficial to reduce the diffusive and mass transfer resistance of the desulfurization reaction and to improve the utilization of the active phase.A series of zinc-manganese composite oxide desulfurization sorbent were hydrothermally synthesized using different types of zinc salts and hexamethylenetetetramine(HMTA)on nanofiber supporter loaded with MnO2 seed layer,and the nucleation and growth mechanisms of the active-phase crystals were elucidated by exploring the interrelationships between the type of counter-ion and the grain size of zinc-manganese oxides.It was shown that the counter-ion in hydrothermal solution have a significant inhibitory behavior for the complexation and condensation reaction of Zn2+with OH.Compared with NO3-and SO42-,the average grain size of Mn3O4 crystal phase in the desulfurization sorbent decreased by 39.2％,and the particle size of the active phase decreased by 24.7％.Meanwhile,desulfurization tests showed that the overall active component utilization of the desulfurization sorbent ZN@MCNFs was 7％higher than that of ZS@MCNFs.The crystal growth mechanism of zinc-manganese-based desulfurization sorbent elucidated by the research provides theoretical support for the development of metal oxide desulfurization sorbent with excellent performance.