添加氢气对LPG/空气预混火焰结构的影响

针对氢气添加的LPG(液化石油气)+空气预混火焰结构进行了数值研究, 详细计算了在含氢比a为0%到45%、稀释引子D为21%到16%条件下的自由蔓延火焰, 得到了不同燃烧条件(φ=0.7-1.4)下的绝热燃烧速率变化规律. 由于LPG中的主要成分为丙烷和丁烷, 作者针对C3和C4物质提出了详细化学反应动力学系统, 并针对氢气添加的丁烷燃烧过程进行了数值计算, 得到了与实验相一致的结果, 验证了改进的详细化学机理的有效性. 此外, 进一步计算了对撞双火焰的加氢LPG火焰, 更加深入地探讨了火焰拉伸对燃烧稳定性和温度的影响, 重点研究了φ在0.5到0.7的稀薄燃烧, 验证了氢气添加可以有效提高稀薄燃烧条件下熄火拉伸率, 扩大稀薄燃烧的极限, 增加火焰的稳定性.     

微波在柴油机滤烟器催化再生中的应用：Ⅱ.滤烟器在含氧气氛中的微波加热 ？

采用柴油机台架装置及微波加热装置,考察了柴油机催化滤烟器的微波加热再生效应。结果表明,过滤体上捕集的碳烟量对催化滤烟器在氧气中的微波加热燃烧再生至关重要只有捕集的碳烟量超过某一直限值,滤烟器上的碳烟才有可能被微波加热至起燃温度;但碳量也不可超过一上限值,否则滤烟器的微波加热催化再生可能失去控制,碳烟急剧燃烧产生的热量将使过滤基质烧结。     

电动态平衡技术在研究单颗粒煤燃烧中的应用

利用电动态平衡技术，将单个带电煤颗粒悬浮在样品池中，可以实现煤颗粒燃烧过程的原位微观研究。本文简要介绍了电动态平衡技术的原理和相关的操作方法，总结了该技术应用于煤燃烧研究的进展，进一步探讨了结合时间分辨光谱技术研究煤燃烧物理化学过程细节的可行性与发展前景。目的在于向国内研究者介绍这一新技术并激发更多的研究兴趣。     

温度对共沉淀法制备LaMnAl11O19催化剂的影响

天然气燃烧具有污染物排放少、能源利用率高等特点。但是传统的燃烧方法温度较高，对系统材料要求较高，同时空气中的N2被氧化为NOx，造成严重的环境污染。采用催化燃烧技术可降低燃烧温度、减少污染物的生成。高温催化燃烧是传统燃烧的替代方法，是降低污染，提高能源利用效率的有效途径之一。实现该过程的核心问题是高活性、热稳定性好的耐高温催化剂的研制。     

柴油机尾气净化催化剂的最新研究进展

柴油机尾气排放的污染物已经引起了严重的环境污染问题,催化净化技术是柴油机尾气污染治理必不可少和最有效的处理技术之一,而高效催化剂的研制和开发是催化净化技术的核心.本文以柴油机尾气中最难处理的两种污染物NOx和碳烟颗粒(PM)的催化处理技术为主线,综述了NOx的催化还原(选择性催化还原(SCR)和贮存还原(NSR))催化剂、碳烟的催化燃烧催化剂、NOx和碳烟颗粒同时消除的催化剂及柴油机尾气四效催化剂的最新研究进展,并总结性地提出了目前该研究方向存在的主要问题和发展方向.     

稀土在汽油车尾气净化中的应用

截至2021年底，中国的汽车保有量超过3亿辆，其中汽油车占比90%以上，是中国最重要的汽车类型。为了应对汽油车尾气中的氮氧化物(NO_x)、碳氢化合物(HC)和一氧化碳(CO)等典型污染物，“三效催化剂”这一具有里程碑意义的汽油车尾气后处理技术被开发、应用并不断完善。新近流行的汽油缸内直喷(GDI)技术会导致显著的颗粒污染物(PM)排放，由此又催生了汽油车颗粒物过滤器(GPF)技术。上述技术的实施或多或少都需要依赖中国战略资源——稀土的参与。本文首先对各类汽油车尾气净化技术的发展进行了回顾，之后重点分析了(以CeO₂为主的)稀土材料在三效催化剂储氧材料、催化剂载体/贵金属稳定剂和汽油车颗粒物过滤器中的具体应用方式和效果。可以看出，随着新型稀土材料的开发和技术迭代，现代汽油车尾气净化技术正在变得越来越高效、越来越便宜。最后，本文对汽油车尾气净化用稀土材料的发展趋势进行了展望，分析了相关产业未来升级的重点和难点所在。     

国家燃烧热基准的技术改造

对国家燃烧热基准进行了全面改造?改造后的燃烧热计量基准装置一体化、仪器化、自动化程度大大提高，测量结果准确可靠，为燃烧热量值的溯源和传递提供了技术保证。     

柴油机烟碳的微波加热燃烧

本文讨论了将新颖的微波加热技术应用于柴油机烟碳燃烧的可行性。通过研究柴油机烟碳和商品碳黑的组成和结构与介电的关系，以及观察它们在微波场中的加热和燃烧行为，发现柴油机烟碳的介电性和损耗性很适宜于使用微波进行加热燃烧。实验结果表明，在含氧量为１０％的模拟排气条件下，当微波入射功率逐渐增至９００Ｗ时，可使柴油机的烧却率达５０％。文中亦考察了一次燃烧产物中ＣＯ２摩尔分离在燃烧过程中的变化 。     

柴油机烟碳的微波加热燃烧 Ⅰ．柴油机烟碳的介电性能与微波加热特征

本文讨论了将新颖的微波加热技术应用于柴油机烟碳燃烧的可行性。通过研究柴油机烟碳和商品碳黑的组成和结构与介电性能的关系，以及观察它们在微波场中的加热和燃烧行为，发现柴油机烟碳的介电性和损耗性很适宜于使用微波进行加热燃烧。实验结果表明，在含氧量为１０％的模拟排气条件下，当微波入射功率逐渐增至９００Ｗ时，可使柴油机烟碳的烧却率达５０％。文中亦考察了一次燃烧产物中ＣＯ_２摩尔分率在燃烧过程中的变化。     

Thermodynamic and Equilibrium Composition of Using Iron Oxide as an Oxygen Carrier Nonflame Combustion Technology Analysis in

本文介绍了一种新的燃烧体系--熔融盐循环热载体无烟燃烧技术。这种燃烧体系杜绝环境污染气体NOx和CO2的排放，可以实现真正零排放的目标。计算了以Fe2O3作为氧载体的无烟燃烧体系的热力学参数。用最小吉布斯自由能原则，分析了Fe2O3与CH4的平衡组成。分析表明，如果要想在产物中产生高纯度的CH4完全氧化产物CO2和H2O，Fe2O3与CH4必须达到高摩尔比，如果Fe2O3的量不足，就会产生较多的部分氧化产物如CO，H2甚至C     

载体焙烧温度对稀燃天然气汽车尾气净化Pd/Zr0.5Al0.5O1.75催化剂性能的影响

以不同温度焙烧得到的Zr0.5Al0.5O1.75复合氧化物为载体,制备了系列1.5%Pd/Zr0.5Al0.5O1.75催化剂样品.采用N2吸附-脱附、X射线衍射、H2程序升温还原、O2程序升温脱附及CO化学吸附等手段对催化剂进行了表征,并测试了催化剂在模拟稀燃天然气汽车尾气中的活性和抗H2O中毒性能.结果表明,载体...     

BaFeO_(3-x)与Cu-ZSM-5耦合催化剂的NO_x储存还原性能

为替代传统的贵金属基NOx储存还原(NSR)催化剂,本文设计并制备了不含贵金属的BaFeO3-x+CuZSM-5耦合催化剂,用于催化消除稀燃发动机尾气中的NOx.在稀燃阶段,NO在BaFeO3-x催化剂上发生了氧化和储存反应;在富燃阶段,从BaFeO3-x催化剂中脱附出来未能消除的NOx被置于其后的Cu-ZSM-5催化剂进一步催化消除.实验结果表明,BaFeO3-x+Cu-ZSM-5耦合催化剂的工作温度窗口被拓宽到250-400°C,同时NOx消除性能得到了显著提高:NOx转化率最高可达98%,N2选择性接近100%.     

The catalyst industry of Japan (2)

The trends of the catalyst industry in Japan are described based on the statistical data published by the Japanese government offices. Three topical items in the recent catalytic technology developments in Japan are described: resid FCC, methylmethacrylate, and emission control for lean-burn engines.     

金属-ZSM-5/堇青石整体式催化剂上稀燃汽车尾气的净化

 在原位合成的ZSM-5/堇青石整体式样品基础上制备了几种金属(Cu, In或Ag)改性的ZSM-5/堇青石催化剂,并将其应用于稀燃发动机尾气的净化. 结果表明, Cu-ZSM-5/堇青石催化性能最好,尾气中的三种主要污染物NOx, CO和HC可以同时得到净化. 用微量(0.02%)贵金属(Pd, Rh或Ir)对Cu-ZSM-5/堇青石进一步改性,所得催化剂对CO的净化能力大大增强,保持高NOx转化率的温度窗口也大大加宽,因而该催化剂在稀燃汽车尾气净化方面具有潜在的应用前景. 微量贵金属对Cu-ZSM-5/堇青石催化剂的改性作用也在文中进行了讨论.     

Pt/Si-MCM-41介孔结构对低温NO+H2+O2反应的影响

将Pt/Si-MCM-41用于H2选择催化还原(H2-SCR)消除NO的反应. X射线衍射分析、N2吸附/脱附、氢吸附和透射电镜等分析结果表明,介孔Si-MCM-41具有大的比表面积和孔体积有利于活性组分Pt的分散, Pt/Si-MCM-41催化剂在富氧和80000 h-1空速的条件下,其H2-SCR低温活性在100 ℃达到60.1%,优于Pt/Si-ZSM-5和Pt/SiO2催化剂,其选择性在120 可达70%. 当Si-MCM-41的介孔结构被破坏时,H2-SCR反应活性明显下降,最大活性在120 ℃仅为15%. 漫反射红外光谱(DRIFTS)测试表明, —NO3物种是Pt/Si-MCM-41催化剂在H2-SCR反应中的主要中间物种.     

BaFeO3-x与Cu-ZSM-5耦合催化剂的NOx储存还原性能

为替代传统的贵金属基NO_x储存还原（NSR）催化剂,本文设计并制备了不含贵金属的BaFeO_3-x+Cu-ZSM-5 耦合催化剂,用于催化消除稀燃发动机尾气中的NO_x. 在稀燃阶段,NO在BaFeO_3-x催化剂上发生了氧化和储存反应;在富燃阶段,从BaFeO_3-x催化剂中脱附出来未能消除的NO_x被置于其后的Cu-ZSM-5催化剂进一步催化消除. 实验结果表明,BaFeO_3-x+Cu-ZSM-5 耦合催化剂的工作温度窗口被拓宽到250-400 ℃,同时NO_x消除性能得到了显著提高：NO_x转化率最高可达98%,N₂选择性接近100%.     

Effects of Air/H<Subscript>2</Subscript>O Discharge Plasma on Propane Combustion Enhancement Using Dielectric Barrier Discharges

Combustion provides about 80% energy for our daily life and industrial production. But thermal efficiency of traditional combustion technologies is low, which causes energy waste and serious environmental pollution. In order to improve the combustion efficiency, a combined method based on non-equilibrium plasma generated by dielectric barrier discharge and OH radicals coming from water-steam additive was proposed in this work, and plasma assisted propane combustion was examined and evaluated. The results indicated that when relative humidity (RH) was 20% and applied peak voltage was fixed at 8.75 kV, the relative intensity of OH radical and the flame temperature reached the maximum value at the flame root. At the same time, propane combustion was the most complete. In addition, we found that the erosion of the inner electrode was weakened by H₂O addition, and the symmetry of discharge current was changed from symmetry to asymmetry with the increase of RH. Compared with the pure air undischarged combustion, when the relative humidity was 20% and under the discharge conditions of 8.75 kV, the lean-burn extinction limit was extended to 0.4,which is far lower than the traditional lean-burn limit (0.51).     

Influences of Mesoporous Structure on the NO+H2+O2 Low Temperature Reaction over Pt/Si-MCM-41 Catalyst

It was found that Si-MCM-41 mesoporous molecular sieves as a support of noble metal Pt could be used for the selective catalytic reduction of NO by hydrogen (H₂-SCR) under lean-burn conditions. Pt/Si-MCM-41, together with Pt/Si-ZSM-5 and Pt/SiO₂, was characterized by X-ray diffraction analysis (XRD), nitrogen adsorption/desorption, hydrogen adsorption, and transmission electron microscopy (TEM). The results indicated that Pt/Si-MCM-41 had the best H₂-SCR activity in comparison with Pt/Si-ZSM-5 and Pt/SiO₂ catalysts and that the maximum conversion of NO was up to 60.1% at 100 °C and a gas hourly space velocity (GHSV) of 80000 h_-1 under lean-burn conditions. Characterization showed that the large surface area and pore volume of MCM-41 favored the dispersion of Pt. The maximum NO conversion of Pt/Si-MCM-41 catalyst decreased obviously to 15% at 120 °C when the pore structure of Si-MCM-41 support was destroyed. The reaction mechanism over Pt/Si-MCM-41 was investigated using in situ diffuse reflectance infrared spectroscopy (DRIFTS), which revealed that the main reaction intermediates should be nitrate species during NO reduction.     

Aberration-corrected STEM imaging of Ag on gamma-Al2O3.

Ag on gamma-alumina is a promising catalyst for hydrocarbon selective catalytic reduction in lean-burn gasoline and diesel engines for transportation applications. Although much is known about the mechanism of NOx reduction and the various intermediates, little agreement exists on the nature of the active silver species. In the present work, aberration-corrected STEM has provided new information about the nature of Ag on alumina both as impregnated and following treatments at various temperatures with exposure to simulated exhaust gas. Ex situ techniques have provided new insights into the evolution of Ag on alumina following exposure to temperature and simulated exhaust gas.     

Pd catalysts supported on modified Zr0.5Al0.5O1.75 used for lean-burn natural gas vehicles exhaust purification

Composite supports Zr0.5Al0.5O1.75 modified by metal oxides,such as La2O3,ZnO,Y2O3 or BaO,were prepared by co-precipitation method,and palladium catalysts supported on the modified composite supports were prepared by impregnation method.Their properties were characterized by X-ray diffraction(XRD),NH3 temperature-programmed desorption(NH3-TPD),H2 temperature-programmed reduction(H2-TPR),N2 adsorption/desorption,and CO-chemisorption.The catalytic activity and the resistance to water poisoning of the prepared Pd catalysts were tested in a simulated exhaust gas from lean-burn natural gas vehicles with and without water vapor.The results demonstrated that the modified supports had an apparent effect on the performance of Pd catalysts,compared with the Pd catalyst supported on the unmodified ZrAl.The addition of ZnO or Y2O3 promoted the conversion of CH4.In the absence of water vapor,Pd/ZnZrAl exhibited the best activity for CH4 conversion with the light-off temperature(T50) of 275℃ and the complete conversion temperature(T90) of 314℃,respectively.However,in the presence of water vapor,Pd/YZrAl was the best one over which the light-off temperature(T50) of methane was 339℃ and the complete conversion temperature(T90) was 371℃.These results indicated that Pd catalyst supported on the modified composite ZrAl support showed excellent catalytic activity at low temperature and high resistance to H2O poisoning for the exhaust purification of lean-burn natural gas vehicles.