利用硫酸氧钒制备钒炭催化剂用于烟气脱硫(英文)

Using vanadyl sulfate to prepare carbon-supported vanadium catalyst for flue gas desulfurization

利用硫酸氧钒制备钒炭催化剂用于烟气脱硫。研究发现,负载在活性炭上的硫酸氧钒极易被氧化为五价钒硫酸盐,这些五价钒硫酸盐具有很高的氧化SO2的活性,极大地促进了SO2在活性炭上的脱除。而且,通过煅烧可以将五价钒硫酸盐分解为五价钒氧化物,最佳煅烧温度为500℃,由于煅烧后用于储存硫酸的微孔孔容增加,SO2的吸附容量得到了进一步提高,由此表明,利用硫酸氧钒可以制备传统的V2O5/AC催化剂。为了获得完全氧化的钒物种,对煅烧后的催化剂进行了空气中预氧化,但由于含氧官能团的形成、炭载体的烧蚀以及钒的还原,预氧化不利于脱硫。此外,研究中得到初步证据证明脱硫过程中V2O5/AC催化剂中五价钒氧化物转变成了五价钒硫酸盐,结合五价钒硫酸盐所表现出的氧化SO2的能力,推测SO2在V2O5/AC上的脱除遵循以下机理:五价钒氧化物先转变为五价钒硫酸盐,后者催化氧化SO2为硫酸。

Vanadyl sulfate （VWOSO4） was used to prepare carbon-supported vanadium catalyst for flue gas desulfurization. The VwOSO4 impregnated on activated carbon （AC） was easily oxidized into vanadium（V） sulfate phase （possibly V203 （SO4 ）2 ） in air, which exhibited high catalytic activity toward SO2 oxidation, thus significantly enhancing SO2 retention on AC. Furthermore, the vanadium（V） sulfate can be decomposed upon calcination in nitrogen with optimum temperature of 500 ℃ to form vanadium （V） oxide, further improving SO2 retention mainly due to increase in micorpore volume suitable for sulfate storage and showing suitability of vanadyl sulfate to prepare traditional V2O5/AC catalyst. To obtain fully oxidized vanadium oxides, preoxidation was carried out on catalyst after calcination. However, due to ablation of carbon support, reduction of vanadium and/or formation of surface oxygen groups, the preoxidation was negative for SO2 retention. Additionally, this paper provided preliminary evidence indicating transformation of vanadium （ V ） oxide in V2 O5/AC into vanadium （ V ） sulfate during desulfurization. Combined with catalytic role of vanadium（V） sulfate for SO2 oxidation, SO2 removal on V2Os/AC likely followed a mechanism that the vanadium （V） oxide firstly transformed into vanadium（V） sulfate and the latter was then responsible for subsequent SO2 oxidation into H2 SO4.