【摘要】 为实现低浓度二氧化硫烟气处理过程中硫的资源化,提出了一种新型二氧化硫烟气净化技术,即二氧化硫碱吸收-低温催化制备硫黄和硫酸氢钠工艺。该工艺首先采用碱液直接吸收净化二氧化硫烟气,再通过低温催化碱吸收液获得含硫产品,实现了硫的资源化。首先通过热力学计算证明了碱吸收液中亚硫酸氢钠的歧化反应在低温条件(<100℃)下发生的可行性。然后研究了反应物浓度对吸收过程和歧化反应过程的影响,结果表明,增加反应物浓度可加快歧化反应速率。此外,研究了硫黄产品的脱稳过程,结果表明,当脱稳加热时间为6 h时,硫黄产率可达到95.97%,所得硫黄产品为纯度较高的单斜硫。该催化过程为固—液—固反应,兼具了多相反应与均相反应的优点。更多还原

【Abstract】 The aim of this study is to develop a new flue gas desulfurization（FGD） process,e.g.SO₂ alkali absorption and Se-catalyzed desulfurized liquid for preparing the sulfur and sodium bisulfate at low temperatures.As is known,the emission of sulfur dioxide is an extremely important social and environmental problem because it may lead to harmful impact on the environment,human health,livestock,and plants.Therefore,it is critical to control SO₂ emission and develop novel clean and healthy gas-fuel technology.To achieve this purpose,one approach is to make efforts to absorb sulfur dioxide first of all by using the alkali liquid to remove SO₂ from the flue gas and desulfurize the liquid containing NaHSO₃.And,then,it is necessary to enact the disproportionation reaction of NaHSO₃ and produce S and NaHSO₄ under low temperatures with the effect of selenium as a catalyst.The aforementioned process can help to realize the resource utilization of sulfur.The results of thermodynamic calculation confirms that there exists a problem of the so-called disproportionation reaction of NaHSO₃,which can be expected to take place at low temperatures（<100℃）.However,the study results suggest that it is possible to use selenium as a catalys’ t to decrease the reaction temperature from 180℃ to 80℃.The optimal pH value to realize this process is 3.5.What is more,we have also made an exploration of the effect of NaOH concentration on the reaction rate and the removal efficiency of SO₂.The results of our exploration suggest that the reaction rate tends to increase with the increase of NaOH concentration with the removal efficiency given no obvious difference.Besides,in order to destabilize the colloidal sulfur in.the solution and get sulfur particles with fast sedimentation,the colloidal sulfur solution can be promoted by heating.Further study on the effect of heating time on the stability of colloidal sulfur shows that a longer heating time is beneficial for the sedimentation and deposition of the sulfur particles.Furthermore,the results of scanning electron microscope（SEM） and X-ray diffraction（XRD） indicate that the product of the sulfur particles is endowed with a high purity and crystallinity in large size after destabilization by heating.What is more,the Se-catalyzed NaHSO₃disproportionation reaction turns to be a solid-liquid-solid phase transformation process,which is characteristic with the advantages of homogeneous and heterogeneous reaction.更多还原