Modeling quenching distance and flame propagation speed through an iron dust cloud with spatially random distribution of particles

In this research combustion of iron dust particles in a medium with spatially discrete sources distributed in a random way has been studied using a numerical approach. A new thermal model is generated to estimate flame propagation speed and quenching distance in a quiescent reaction medium. The flame propagation speed is studied as a function of iron dust concentration and particle diameter. The predicted propagation speeds as a function of these parameters are shown to agree well with experimental measurements. In addition, the minimum ignition energy has also been investigated as a function of equivalence ratio and particle diameter. The quenching distance has been studied as a function of particle diameter and validated by the experiment. Considering random distribution of particles, the obtained results provide more realistic and reasonable predictions of the combustion physics compared to the results of the uniform distribution of particles.     

低温等离子体协同催化降解含硫恶臭污染物

采用共沉淀—喷涂法制备了（Cu5Mn7Zr1O22）0.08/（γ-Al2O3）0.1/堇青石蜂窝陶瓷催化剂。表征结果显示：催化剂孔隙率较高,表面均匀分散着粒径介于20~100 nm的晶体颗粒。以硫化氢和乙硫醇为典型含硫恶臭污染物进行了低温等离子体协同催化降解实验,结果表明：污染物的降解率随着输入功率的增加而提高;与单纯低温等离子体相比,低温等离子体协同催化能获得更好的降解效果。降解机理可能为：在高能电子和活性粒子作用下,H2S或C2H5SH分子中键能较弱的H—S、C—S和C—C键断裂形成·SH、·C2H5、·CH2SH、·CH3等小碎片基团,这些小碎片基团进一步发生聚合、氧化或自由基链式反应,最终降解为CO2、SO2、SO3、H2O等无毒小分子。     

Simultaneous removal of gaseous CO and elemental mercury over Cu-Co modified activated coke at low temperature

Cu-Co multiple-oxides modified on HNO₃-pretreated activated coke (AC_N) were optimized for the simultaneous removal of gaseous CO and elemental mercury (Hg⁰) at low temperature (< 200 °C). It was found that 2%CuOx-10%CoOx/AC_N catalyst calcined at 400°C resulted in the coexistence of complex oxides including CuO, Cu₂O, Co₃O₄, Co₂O₃ and CoO phases, which might be good for the simultaneous catalytic oxidation of CO by Co-species and removal of Hg⁰ by Cu-species, benefiting from the synergistic catalysis during the electro-interaction between Co and Cu cations (CoO ? Co₃O₄ and Cu₂O ? CuO). The catalysis removal of CO oxidation was obviously depended on the reaction temperature obtaining 94.7% at 200 °C, while no obvious promoting effect on the Hg⁰ removal (68.3%-78.7%). These materials were very substitute for the removal of CO and Hg° from the flue gas with the conditions of 8–20 vol.% O₂ and flue-gas temperature below 200 °C. The removal of Hg° followed the combination processes of adsorption and catalytic oxidation reaction via Langmuir-Hinshelwood mechanism, while the catalysis of CO abided by the Mars-van Krevelen mechanism with lattice oxygen species.     

常温催化抗菌研究现状及展望

病原微生物所引发的传染性疾病严重威胁人类健康和生命。传统抗菌技术通常需要外加光、热等能量,如紫外线、光催化、微波等,实际应用受限。常温催化作为一种新型抗菌技术,能够在常温条件下发生催化氧化反应,产生强氧化性的活性氧物种而起杀菌作用。因此,常温催化技术在抗菌领域具有应用优势,综述其抗菌研究现状对于系统性认知常温催化抗菌具有指导意义。本文阐述了常温催化抗菌材料及其活性氧物种产生过程,介绍了常温催化抗菌性能的评价方法,讨论了常温催化抗菌的作用机制,重点分析了常温催化抗菌性能的影响因素。此外,基于国内外常温催化的抗菌研究现状,指出了常温催化抗菌研究存在的问题及未来发展趋势。     

催化超临界水氧化偏二甲肼动力学研究

采用CuO/γ-Al2O3和MnO2/γ-Al2O3为催化剂、H2O2为氧化剂,在一连续流固定床反应器中进行了催化超临界水氧化偏二甲肼实验,得到了COD去除宏观动力学方程.在24 MPa、400～450℃和H2O2过量的情况下,反应对COD分别为1.11级(CuO)和1.26级(MnO2),对氧气分别为0.10级(CuO)和0.12级(MnO2).反应的活化能分别为35.75 kJ/mol(CuO)和37.79 kJ/mol(MnO2),前置因子A分别为9.35×102(CuO)和3.45 ×103(MnO2).     

催化还原脱除地下水中硝酸盐的研究

采用浸渍法制备催化剂Pd-Cu/γ-Al2O3,用BET、ICP、XRD、TEM和EDX对该催化剂进行了表征.以甲酸钠作为还原剂,对催化还原硝酸盐进行了试验研究.结果表明,100 mg·L-1硝酸盐完全反应时总氮的脱除率可以达到87%.催化反应的活性和选择性受pH值、催化剂投加量、甲酸钠浓度和硝酸盐初始浓度等反应条件影响.甲酸钠作为还原剂时只需控制溶液初始pH值,初始pH值过高或过低都会降低催化剂活性;控制初始pH值为4.5,适当降低催化剂投加量和增加甲酸钠的浓度有利于提高催化活性,但选择性会显著降低.初始pH值为4.5时,不同初始浓度硝酸盐的催化还原反应为一级反应.     

An aerosol flow tube study of the interaction of N2O5 with calcite, Arizona dust and quartz

The interaction of N₂O₅ with dispersed samples of Arizona Test Dust (ATD), Calcite (CaCO₃) and quartz (SiO₂) was investigated at varying relative humidity using an aerosol flow reactor. Reactive uptake coefficients, γ, obtained at close to zero relative humidity were (4.8 ± 0.7) × 10⁻³ for CaCO₃, (8.6 ± 0.6) × 10⁻³ for Quartz and (9.8 ± 1.0) × 10⁻³ for ATD. In the case of calcite, evidence was obtained for an enhanced rate of uptake at relative humidities above ≈ 50%. The results are compared to literature values obtained using bulk substrates and to previous aerosol uptake data on Saharan dust.     

低温等离子体协同催化降解VOCs的研究进展

低温等离子体协同催化降解VOCs技术因其具备操作条件简单、去除效率高、CO2选择性好、能量利用率高及产生二次污染物量少等特点,近年来受到国内外研究者的普遍关注。文章在研究大量文献的基础上,概括和分析了低温等离子体协同催化降解VOCs的影响因素和作用机理,并对其在挥发性有机化合物治理中的发展进行了展望。     

高炉粉尘基臭氧催化微电解填料对垃圾渗滤液的处理：与不同填料对比研究

制备了高炉粉尘基微电解(BFD-IE)填料,在臭氧催化的条件下降解垃圾渗滤液,并与商业臭氧催化填料和TEMPO-Cu分子筛填料的处理效果进行对比.采用扫描电镜(SEM)、能谱分析(EDS)和X射线衍射(XRD)等技术对BFD-IE填料和另外两种不同填料进行表征,并对比了三者对垃圾渗滤液中COD和NH₄⁺-N的去除效果.结果表明,在相同的臭氧浓度(20 mg·L^-1)和反应时间下,BFD-IE填料对COD的去除效果(61.3%)要优于商业臭氧催化填料(50.9%)和TEMPO-Cu分子筛填料(39.1%);但对NH₄⁺-N的去除效果存在差异,TEMPO-Cu分子筛填料在20 mg·L^-1臭氧浓度下反应10 min即可实现74.9%的去除率,高于BFD-IE填料(32.7%).此外,经臭氧催化BFD-IE填料处理后的垃圾渗滤液,可生化性显著提升(从0.07提升至0.63),明显优于其他两种填料(0.29和0.39).最后,借助电化学技术和ESR技术,证明了臭氧...     

生油岩与火成岩的相互作用研究初探—有机酸对火成岩的蚀变及过渡金属对有机质演化的催化作用

在发育火成岩的生油层中 ,微生物和热解作用导致生油岩有机质形成有机酸 ,这些有机酸对火山矿物中的金属元素是一种有效的溶剂和迁移介质 ,特别是能促使其中的过渡金属活化和溶解。这样造成与火成岩共存的生油岩内过渡金属含量显著增加 ,一些过渡金属是有机质成烃演化良好的催化剂。同时火山和热液活动还能向生油层提供过渡金属元素 ,从而使与火成岩共生的生油岩油气生成量大大提高。