Experimental And Mechanism Study On Simultaneous Removal Of SO₂ And NO_x Using Jet Bubble Reactor

The pollution status and removal technologies of SO₂ and NOx were consulted andreviewed in this paper.NaClO₂ were screened to be the absorbent of simultaneousdesulfurization and denitrification by experiments.Simulating coal-fired power plantconditions,experiments on removal of SO₂ and NO by NaClO₂ solution were carried outin a self-designed bubble reactor and a medium-scale CT-121 reactor.Based on theremoval products analysis and oxidation-reduction potential,the reaction and transfercharacteristic of the desulfurization and denitrification were revealed.The possibilityand limitation of the simultaneous desulfurization and denitrification using NaClO₂ acidsolution were calculated and analyzed by chemical thermodynamic methods.Reactionkinetics of the simultaneous desulfurization and denitrification using NaClO₂ solutionwere investigated by experiments.NaClO₂ was determined to be the absorbent of the simultaneous desulfurization anddenitrification by screening experiments in a self-designed bubble reactor.Thecorresponding law and the optimal conditions were determined by the investigations ofthe effect of NaClO₂ concentration,original pH value,reaction temperature,flue gasflow as wellas original concentration of SO₂ and NO on the removal efficiencies.Underthe optimal conditions,the simultaneous removal efficiencies of SO₂ and NO by NaClO₂solution reached 100% and 95%,respectively.Based on the results of the packaged experiments and the practicle conditions ofcoal-fired power plants,the scale-up experiments on the simultaneous removal of SO₂and NO by NaClO₂ solutions were carried out in a medium-scale CT-121 reactor afterthe corresponding experimental parameters and the range were determined.Theexperimental results revealed the influence law of each parameter,and the optimalconditions were determined.Under the optimal conditions,the simultaneous removalefficeincies of SO₂ and NO reached 82.0% and 92.8% above,respectively.The disproportion reactions of ClO₂ in the NaClO₂ solution were derived,and thepossibility,limitation and the predominant products of the reactions were analyzed bychemical thermodynamic methods.The conformational changes of chloride compoundsin NaClO₂ solution were studied by experiments.The experimental results indicate thatthe main ion in the NaClO₂ solution is ClO₂^- with a small amount of ClO₂.The results of products analysis of the simultaneous desulfurization anddenitrification by NaClO₂ solution show that sulfate radical ion is the predominantdesulfurization product,while nitrate radical ion is the predominant denitrification product.According to the products analysis and oxidation-reduction potential,thereaction processes of SO₂ and NO in gas phase and liquid phase were investigated,respectively.And the total reaction equations of the desulfurization and denitrificationby NaClO₂ acid solution were determined.The transfer characteristic of thedesulfurization and denitrification by NaClO₂ solutionwasexplored by two-film theory.Molar reaction enthalpy,molar formation Gibbs function,SO₂ and NO partialpressure at different reaction temperature as well as constant of reaction rate werecalculated and analyzed by chemical thermodynamic methods.The results show thatsimultaneous removal of SO₂ and NO is feasibile in thermodynamic category.The reaction kinetic process of the simultaneous desulfurization and denitrificationby NaClO₂ solution were investigated by experiments.The experimental results indicatethat the removal reaction of SO₂ and NO are divided into two stages,as fast and slowreaction zone.Based on the experimental data,reaction partial order,macroscopy rateconstant and apparent activation energy of SO₂ and NO were calculated.