氢对氧化铁脱硫剂脱硫行为的影响

The effects of hydrogen on the desulfurization behavior of iron oxide sorbents

以钢厂赤泥为活性组分,以聚苯乙烯(Polystyrene)微球为造孔剂,加入一定量黏土作黏合剂,经干混法制备氧化铁脱硫剂。采用压汞法、氮吸附、XRD对脱硫剂进行表征;采用热重法考察了氢以及预还原对脱硫剂性能的影响。结果表明:有氢与无氢气氛下氧化铁脱除H2S的行为不同,有氢气氛下氧化铁脱除H2S的速率小于无氢气氛下的脱硫速率,引起这种差异的原因是两种气氛下氧化铁脱硫的机理不同;脱硫剂在经H2深度预还原后,呈现出低价态,低价铁的本征硫化速率虽然高于氧化铁,但由于过度还原会引起脱硫剂的结构塌陷,反而会抑制脱硫反应的进行。

Iron oxide sorbent was prepared with the dry-mixing method using red-mud from steel factory as the activa- ting component, the synthesized polystyrene （PS） microspheres as pore-forming material and clay as binder. The sorbent was characterized by nitrogen adsorption, mercury porosimetry, and XRD. Thermogravimetric analysis was used to investigate the effects of hydrogen, as well as pre-reduction, on the behavior of the sorbent for H2 S removal. The results show that iron oxide sorbent exhibites different behaviors in the atmosphere with or without hydrogen. H2S removal from the hydrogen-containing gas mixture is slower than from mixtures without hydrogen ,which is due to the different mechanism of the reaction in different atmospheres. Iron oxide is converted to the state of low oxidation after being reduced by hydrogen. Iron with low oxidation state may react with HzS quickly in intrinsic kinetics. However ,the sulfidation is unexpectedly inhabited owing to the destruction of the sorbent structure caused by deep reduction.