电化学法同时除去SO_2/NO_X工艺过程的理论分析

提出了一条同时除去SO2 与NOX 气体的电化学新工艺 .SO2 气体用NaOH溶液吸收后形成HSO-3 ,后者再在电解槽阴极室中以Pb为电极 ,pH值在 4～ 7之间时电解还原为连二硫酸盐 .NO气体通入到含Ce4 的气 -液反应柱中被氧化为高价氮氧化合物 ,该混合物直接在电解槽阳极室中氧化 ,从而再生出Ce4 ,用二 -2 -乙基己基磷酸的煤油溶液萃取出Ce4 后 ,水溶液相中通入含氧的氨气时生成NH4 NO3 .Ce4 经反萃取后再返回到气 -液反应柱中与NO气体反应 .热力学与文献研究结果表明 ,HSO-3 电化学还原为S2 O2 -4 的过程为动力学控制 ,当溶液中含硫物质的浓度均为 0 .0 0 1mol·dm-3时 ,HSO-3 电解还原为S2 O2 -4 的热力学稳定性提高 .图 3 ,表 2 ,参 9.

A novel process chart for electrochemical removal of SO_2/NO_X and its theoretical analysis

A new electrochemical process chart for simultaneous removal of SO 2/NO X has been proposed in this paper. SO 2 is absorbed by NaOH solution to form HSO 3 - which is electrochemically reduced into dithionate at a Pb cathode and pH 4-7.NO is oxidized into high valence nitrogen-compounds in gas-liquid absorption column by redox mediator Ce 4 , then the reaction mixture is sent to anode compartment where Ce 4 is electrochemically regenerated. When Ce 4 is extracted by an organic phase (di-2ethylhexylphosphoric acid in kerosene),the aqueous phase is bubbled through aerated ammonia to produce NH 4NO 3.Thermodynamic analysis shows that electrochemical reduction of HSO - 3 into dithionite is controlled dynamically, not thermodynamically, and that concentration decrease of the sulfur-compounds will be helpful to increase thermodynamic stability of dithionite produced by electrochemical reduction of HSO - 3.3figs.,2tabs.,9refs.