添加金属氧化物的V2O5/AC在烟气脱SO2及脱SO2后H2再生制备硫磺的活性研究

Metal oxide doped V_2O_5/AC catalysts for flue gas desulfurization and elemental sulfur production during regeneration with H_2

干法脱除烟气SO2的多种催化剂均可在H2气氛中再生,直接制备硫磺。该过程的实现不仅要求再生尾气循环,而且要求催化剂具有双重功能,即在脱硫过程中催化氧化SO2为H2SO4以及在再生过程中将催化还原释放出的SO2进一步转化为硫磺。添加有金属氧化物的V2O5/AC催化剂具备双重功能。着重考察了添加Ce、W、Fe、Co等氧化物的V2O5/AC催化剂烟气SO2脱除能力及脱除SO2后经H2再生制备硫磺的能力,并对添加Co的催化剂进行了优化。结果表明,在这类催化剂中,对烟气脱SO2起主要催化氧化作用的是V2O5,对H2再生硫磺制备起作用的是添加的金属氧化物。除Ce2O3外,WO3、Fe2O3和CoO都提高了再生中的硫磺收率,CoO的作用最为显著。较合适的催化剂组成是1%V2O5和0.5%CoO。这些金属氧化物在AC上的担载方法,对烟气脱SO2和H2再生结果的影响不明显。硫磺的生成需要CoO向CoS2的转变,再生后催化剂上残余有部分CoS2,且残余硫量还与V2O5量有关。

Many spent catalysts for the flue gas desulfurization under dry conditions can be regenerated to produce elemental sulfur with H2, which requires the tail gas recycle during the regeneration and the catalysts with dual functions for SO2 oxidation during desulfurization and released SO2 reduction during regeneration. A number of metal oxide doped V2O5/AC catalysts for flue gas SO2 removal and elemental sulfur production during H2-regeneration were studied, Results show that V2O5 plays an important role in SO2 removal, while the metal oxides play important roles in elemental sulfur production. WO3, Fe2O3 and CoO additives can improve the elemental sulfur yield （ESY） and CoO has the highest activity. A catalyst with 1% V2O5 and 0.5% CoO on AC is found to be the best one, and the catalyst preparation methods used in this paper show little effect on the performance of the catalyst. The transformation of CoO to CoS2 is necessary for elemental sulfur production. It is found that the regenerated catalysts contain some CoS2 which is associated with the vanadium amount in catalyst.