Study on method and mechanism for simultaneous desulfurization and denitrification of flue gas based on the TiO_2 photocatalysis

Based on the TiO2 photocatalysis mechanism, a new method of simultaneous desulfurization and denitrification from flue gas was proposed. Preparation of TiO2 photocatalyst, design of photocatalysis reactor and influencing factors for simul- taneous removal of SO2 and NO, and removal mechanism of SO2 and NO were studied. After the optimal values of concentration of O2 in flue gas, the relative humidity of flue gas and the irradiation time in the photocatalysis reactor were used, the efficiencies of removal for SO2 and NO can be achieved above 98% and about 67%, respectively. According to the results of removal products analysis, the re- moval mechanism of SO2 and NO based on TiO2 photocatlysis can be put forward, namely, SO2 was oxidized to SO3 partly, the bulk of NO was oxidized to NO2, and both were removed by resorbing finally.

Kinetics of pozzolanic reaction for preparation of flue gas desulfurizer from fly ash and Ca(OH)_(2)

A kinetic model of the pozzolanic reaction for the preparation of flue gas desulfurizers from fly ash and Ca(OH)_(2) was deduced on the basis of solid phase reaction kinetic theory.Kinetic expressions and parameters were obtained and verified by experiment.A comparison of calculated results with experimental results showed that precision in kinetic expressions was good.The apparent reaction rate constants of the pozzolanic reaction could be raised by increasing the specific surface area of fly ash and the hydration temperature,and by using a suitable additive.

NH_3选择性催化还原NO_X的实验研究

在固定床反应器中 ,对NH3 选择性催化还原NOX(SCR)进行实验研究。SCR反应在催化剂表面进行 ,催化剂的表面积和微孔特性很大程度上决定了催化活性。温度、接触时间、催化剂中V2 O5的量和NH3 投入量对SCR反应有较大影响。适宜反应温度、接触时间、V2 O5的量和n(NH3 ) /n(NOX)分别是 310℃、2 0 0ms、4 .5 %和 1.1。实验结果表明 ,在适宜反应条件下 ,NOX 脱除率可达 90 %。

选择性非催化还原法脱除NOx的实验研究

在夹带流反应器中 ,对选择性非催化还原 (SNCR)法脱除NOx 进行了实验研究。在 80 0～ 12 0 0℃下喷射尿素还原剂或几种铵盐还原剂能脱除NOx ,其中尿素还原剂脱NOx 的能力最强 ,碳酸氢铵还原剂次之。在n(N) /n(NOx) =1 5 ,90 0～ 10 0 0℃和 2s的实验条件下 ,尿素的NO和NO2 脱除率分别能达到 70 %～ 80 %和 45 %～ 5 0 % ,排放的N2 O的质量分数小于 7× 10 -6。温度和停留时间对NOx 的脱除效率和N2 O生成速率有较大影响 ,最佳温度为 90

固定化微生物两级还原耦合络合吸收工艺脱除NO_x的动力学研究

分析了固定化微生物两级还原耦合络合吸收工艺脱除NOx的动力学过程,建立了生物反应器内固定化微生物还原Fe(Ⅱ)EDTA-NO和Fe(Ⅲ)EDTA的生化反应模型以及固定化生物小球的扩散-反应模型。分析结果表明:固定化反硝化菌还原Fe(Ⅱ)EDTA-NO的最大反应速度γmax为6.97×10-6 mmol/(m3·s-1),半饱和常数Km为0.001 6mmol/m3;固定化铁还原菌还原Fe(Ⅲ)EDTA的最大反应速度γ′max为6.805×10-5 mmol/(m3·s-1),半饱和速率常数K′m为0.013 73mmol/m3;Fe(Ⅱ)EDTA-NO和Fe(Ⅲ)EDTA的微生物还原过程均由内扩散控制,后期设计运用中应着力提高小球内反应物的扩散速率。