Ni/Al2O3催化剂上甲烷部分氧化制合成气反应CO2主要来源

负载型金属催化上甲烷催化部分氧化剂合成反应机理存在着燃烧－重整机理和直接氧化之争,如果反应按燃烧－重整机理进行,则ＣＯ２则是反应的一次产物而ＣＯ２是二次产物;如果反应按直接氧化机理进行,则ＣＯ是一次产物。本文采用同位素瞬变技术,对Ｎｉ／Ａｌ２Ｏ３催化上甲烷部分氧化制合成气反应中ＣＯ２的来源进行了研究,结果表明ＣＯ２同ＣＯ－样,主要来源于催化剂表面ＮｉＯ与甲烷分解生成的ＮｉｘＣ的反应,这就有力地证明     

化学链燃烧过程中铁基烧结返矿载氧体反应活性及结构研究

使用流化床,以95%的甲烷作为还原性气氛,以烧结过程中烧结返矿作为载氧体,研究其在化学链燃烧过程中的反应活性以及烧结返矿在氧化还原循环中的结构特征。对烧结矿原料、还原后以及氧化再生的烧结矿进行形貌结构及物性表征。结果表明,在初始氧化循环过程中,烧结返矿的载氧能力和反应活性有显著的提高;前25个循环过程中,烧结返矿的比表面积显著增大,比表面积的增大是提高烧结返矿反应活性的主要原因之一。随着循环的进行,烧结返矿表面出现裂纹并逐渐加大。Raman检测结果显示,在还原过程中有新的铁晶型,纤铁矿(γ-Fe OOH)生成,而纤铁矿(γ-Fe OOH)的生成将降低烧结返矿的载氧能力。氧化循环过程中,采用甲烷作为还原性气体,并未发现有碳沉积现象的产生。     

CO_2在Ag－Ba－Ca－K／α－Al_2O_3上的吸附及其在乙烯环氧化反应

应用ＦＴＩＲ和脉冲反应技术研究了ＣＯ_２和Ｏ_２在Ａｇ－Ｂａ－Ｃａ－Ｋ／α－Ａｌ２Ｏ３上的吸附及ＣＯ２对Ｃ２Ｈ４环氧化、完全氧化及环氧乙烷（ＥＯ）深度氧化反应的影响．研究结果表明，ＣＯ２和表面吸附氧在负载银催化剂表面存在竞争吸附，ＣＯ２对表面吸附氧有置换作用，该作用降低了银催化剂表面吸附氧的浓度，并且所形成的碳酸根物种改善了乙烯环氧化反应活住氧种的表面分布，对Ｃ_２Ｈ_４的环氧化反应有一定的抑制作用，但是对Ｃ２Ｈ４和ＥＯ的深度氧化反应的抑制作用更强，使得乙烯环氧化反应的选择性得到改善．     

CO2在Ag—Ba—Ca—K／α—Al2O3上的吸附及其在乙烯环氧化反应中的抑制作用

应用ＦＴＩＲ和脉冲反应技术研究了ＣＯ２和Ｏ２在Ａｇ－Ｂａ－Ｃａ－Ｋ／α－Ａｌ２Ｏ３上的吸附及ＣＯ２对Ｃ２Ｈ４环氧化，完全氧化及环氧乙烷（ＥＯ）深度氧化反应的影响。研究结果表明，ＣＯ２和表面吸附氧在负载银催化剂表面存在竞争吸附，ＣＯ２对表面吸附氧有置换作用，该作用降低了银催化剂表面吸附氧的浓度，并且所形成的碳酸根物种改善了乙烯环氧化反应活性氧种的表面分布，对Ｃ２Ｈ４的环氧化反应有一定的抑制作用，但是     

红外光谱研究甲烷和氧与SrO-La2O3/CaO表面的相互作用

在甲烷氧化偶联（ＯＣＭ）反应条件下，用原位红外光谱研究ＳｒＯ－Ｌａ２Ｏ３／ＣａＯ催化剂，结果表明，晶格氧使甲深度氧化，Ｌａ２Ｏ３和ＣａＯ具有活泼的晶格氧，ＳｒＯ的晶格氧比较稳定，气相氧通过催化剂表面消耗掉的晶格氧，加速甲烷了深度氧化，另一方面，催化剂表面的碳酸根物种在氧气氛下分解，在Ｌａ２Ｏ３和ＬＣ催化剂中，催化剂表面Ｌａ２Ｏ２（ＣＯ３）的分解形成配位不饱和的晶格氧Ｏ＾２－，并为气相氧吸附提供氧空     

半导体催化膜上泵氧甲烷氧化偶联反应的研究 Ⅱ.联合体系的反应

在常压及６５０℃下，以含１％Ｏ２的甲烷－氧混合气进料，考察了在ＣａＯ，ＳｒＯ，ＺｎＯ，ＴｉＯ２，ＣｅＯ２和ＭｎＯ２膜上外加电流为－９０～９０ｍＡ范围内联合体系的甲烷氧化偶联反应，结果表明，在ｐ型和ｎ型半导体催化膜上，发生ＮＥＭＣＡ效应的增强因子有一极值，联合体系中泵氧ＯＣＭ反应的Ｃ２烃选择性低于开路体系中反应的Ｃ２烃选择性，根据总反应速率求出了总传递系数及电化学影响效率，电化学影响效率随ｎ型电导率     

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催化再生

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下限值,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． 此碳烟上下限再生窗口随催化剂活性的差异而有所改变． 研究中还发现,在再生过程中,产物中ＣＯ和ＣＯ２ 的比率有较大波动．     

碳氧定向反应Fe／C系催化剂中助剂的作用

本文采用微反－色谱，穆斯堡尔谱及ＸＰＳ等分析手段，研究了碳氧定向反应生成ＣＯ的Ｆｅ／Ｃ系催化剂中助剂Ｋ，Ｃｒ的作用。结果表明，助剂能大大提高定向氧化反应活性，并能稳定主活性组分的价态和提高其分散度。复合催化剂Ｆｅ－Ｋ－Ｃｒ／Ｃ无论在催化活性，稳定性及抗烧结性能方面都优于单组分催化剂。     

铜,锰氧化物的表面过剩氧及其甲苯催化燃烧活性

研究了负载型Ｃｕ－Ｍｎ－Ｏ催化剂对烃类深度氧化的活性，并将ＸＲＤ分析、电子探针考察和表面过剩氧浓度的分布测定等结果与催化剂活性进行了关联。以甲苯催化燃烧为模型反应，除用常规的微反考察其动力学性质外，还用脉冲反应技术研究了表面过剩氧的氧化功能和甲苯的吸附等。Ｍｎ／Ｃｕ原子比为０．８８～０．９时，催化剂活性最好。这是由ＣｕＯ和ＣｕＭｎ２Ｏ４的功能匹配决定的，后者提供与催化作用有关的表面过剩氧，前者促进     

铜、锰氧化物的表面过剩氧及其甲苯催化燃烧活性

研究了负载型Ｃｕ－Ｍｎ－Ｏ催化剂对烃类深度氧化的活性，并将ＸＲＤ分析、电子探针考察和表面过剩氧浓度的分布测定等结果与催化剂活性进行了关联．以甲苯催化燃烧为模型反应，除用常规的微反考察其动力学性质外，还用脉冲反应技术研究了表面过剩氧的氧化功能和甲苯的吸附等．Ｍｎ／Ｃｕ原子比为０．８８～０．９时，催化剂活性最好．这是由ＣｕＯ和ＣｕＭｎ２Ｏ４的功能匹配决定的，后者提供与催化作用有关的表面过剩氧，前者促进甲苯的吸附．对催化剂的作用机理也进行了初步的探讨．     

直接碳固体氧化物燃料电池

碳是重要的能量载体. 直接碳固体氧化物燃料电池（DC-SOFC）是一种直接使用固体碳为燃料的能量转换装置,通过电化学反应,DC-SOFC可将碳所蕴含的化学能直接而连续地转换成电能,转换效率高,产生的CO₂浓度高,易于捕集和后续处理. 本文系统地介绍DC-SOFC的结构组成、工作原理、研究现状和发展趋势,重点介绍了作者课题组在DC-SOFC研究方面的成果和进展,包括单电池和电池组的研制、采用生物质碳和煤炭为燃料时的性能和DC-SOFC在气电联产中的应用探索.     

基于镍基修饰的铁矿石载氧体煤化学链燃烧实验

使用1 kW_th串行流化床反应器,研究了以铁矿石为载氧体以及对铁矿石进行镍基修饰情况下煤化学链燃烧特性,对两种修饰方法(机械混合和浸渍)进行了对比评价。结果表明,铁矿石载氧体具有良好的反应性能和稳定性,是实现煤化学链燃烧的一种比较理想的载氧体。向矿石中机械添加少量NiO/Al₂O₃载氧体,能够有效改善其反应活性,提高系统CO₂捕集率;采用浸渍法修饰的铁矿石载氧体煅烧后,总体微观孔隙结构变差,导致煤气化产物与载氧体间的反应无法充分进行,系统CO₂捕集率显著下降。浸渍修饰的方法和过程需要进一步的研究和改善。     

Mechanism and kinetics for the initial steps of pyrolysis and combustion of 1,6-dicyclopropane-2,4-hexyne from ReaxFF reactive dynamics

We report the kinetic analysis and mechanism for the initial steps of pyrolysis and combustion of a new fuel material, 1,6-dicyclopropane-2,4-hexyne, that has enormous heats of pyrolysis and combustion, making it a potential high-energy fuel or fuel additive. These studies employ the ReaxFF force field for reactive dynamics (RD) simulations of both pyrolysis and combustion processes for both unimolecular and multimolecular systems. We find that both pyrolysis and combustion initiate from unimolecular reactions, with entropy-driven reactions being most important in both processes. Pyrolysis initiates with extrusion of an ethylene molecule from the fuel molecule and is followed quickly by isomerization of the fuel molecule, which induces additional radicals that accelerate the pyrolysis process. In the combustion process, we find three distinct mechanisms for the O(2) attack on the fuel molecule: (1) attack on the cyclopropane, ring expanding to form the cyclic peroxide which then decomposes; (2) attack onto the central single bond of the diyne which then fissions to form two C(5)H(5)O radicals; (3) attack on the alkyne-cyclopropane moiety to form a seven-membered ring peroxide which then decomposes. Each of these unimolecular combustion processes releases energy that induces additional radicals to accelerate the combustion process. Here oxygen has major effects both as the radical acceptor and as the radical producer. We extract both the effective activation energy and the effective pre-exponential factor by kinetic analysis of pyrolysis and combustion from these ReaxFF simulations. The low value of the derived effective activation energy (26.18 kcal/mol for pyrolysis and 16.40 kcal/mol for combustion) reveals the high activity of this fuel molecule.     

Experimental study on combustion characteristics of diesel–hydrogen dual-fuel engine

As a clean and sustainable energy source, hydrogen is widely considered as an engine fuel by top researchers. In view of the fact that the uneven fuel mixture of diesel fuel deteriorated the combustion and emissions process, it is expected to adopt diesel and hydrogen dual-fuel combustion technology to optimize combustion and heat release of diesel engine. In this study, experiments are carried out on a diesel engine and the combustion characteristics of the engine with different hydrogen ratios (RH) are compared. It has been found that hydrogen addition is conducive to accelerate the heat release rate and improve the thermal efficiency. Specifically, compared with pure diesel conditions, the peak pressure increased by 7.7% and the cumulative heat release rate increased by 3.7% under the condition of RH of 20%. Moreover, although the effect on the ignition delay period is not clear, the higher RH brings about earlier heat release center and more cumulative heat release while enhancing the heat release of premixed combustion reducing the diffusion combustion and post-combustion.

     

Magnesium boride sintered as high-energy fuel

Boron was chosen as fuel owing to its excellent thermodynamic values for combustion. The difficulty of the boron in combustion is the formation of a surface oxide layer, which postpones the combustion process, reducing the performance of the rocket engine. In this paper, magnesium boride was sintered as high-energy fuel as a substitute for boron. The combustion heat and efficiency of magnesium boride and boron were determined using oxygen bomb calorimeter. The combustion characteristics of magnesium boride were investigated by thermal analysis, chemical analysis, XRD, and EDS. Results show that the combustion performance of magnesium boride are better than that of amorphous boron in oxygenated environments. The evaporation of magnesium in magnesium boride combustion process prevent the formation of a closed oxide layer, leading to higher combustion efficiency.     

纳米CeO2基固溶体催化柴油机碳颗粒物燃烧性能

采用柠檬酸溶胶鄄凝胶法制备CeO2基固溶体催化剂(Ce0.7Zr0.3O2-δ、Ce0.7Pr0.3O2-δ和Ce0.7Gd0.3O2-δ), 并考察了固溶体和三种常用载体(TiO2、SiO2和Al2O3)及其负载KNO3后的催化碳黑燃烧活性. 结果表明, CeO2基固溶体催化剂具有很高的催化燃烧活性, 其活性接近TiO2、SiO2和Al2O3负载30%KNO3催化剂的活性. 因为纳米CeO2基固溶体的形成, 提高了催化剂的抗烧结能力, 使氧更活泼, 从而提高氧化还原性能, 有利于碳颗粒燃烧. 由于CeO2基固溶体本身的高活性, 因此KNO3的添加不能明显提高CeO2基固溶体催化剂(尤其是Ce0.7Zr0.3O2-δ和Ce0.7Pr0.3O2-δ)的催化燃烧活性, 但KNO3能显著提高TiO2, SiO2和Al2O3的催化燃烧活性.     

Oxygen scavenging enhances exothermic behavior of aluminum-fueled energetic composites

The theoretical heat of combustion for aluminum (Al) and copper oxide (CuO) under ideal conditions is roughly 4,100 kJ kg^?1, but in practice only a fraction of this energy is available for application. Approaching the theoretical value requires innovative strategies for exploiting reaction kinetics. One strategy is to force Al to react CuO as opposed to oxygen from the environment and this approach was shown here to improve the measured heat of combustion significantly. This was achieved through tailoring the mixture using an additive with oxygen affinity prior to Al ignition. The additive is hafnium hydride (HfH₂) and this study examines reaction kinetics for HfH₂ 0–60 mass% concentration range using simultaneous thermal-gravimetric analysis. Results reveal that 0–10 mass% HfH₂ additive enhanced the heat of combustion of Al+CuO by 12 %. The observed enhancement is attributed to HfH₂ creating oxidation competitions that directly influence the combustion performance of Al+CuO. The transition of this equilibrium-based observation to a non-equilibrium fast heating setup is also investigated using plate deformation tests. Exploding bridge wire heads initiated by a capacitive discharge unit are used to dent plates and the deformation energies are estimated to observe the effects of varying composites in a non-equilibrium setting. The presence of HfH₂ showed improved deformation energies for Al+CuO in the 10 % mass HfH₂ range. This work introduces a novel method of using a catalyst in thermite composites to enhance combustive behaviors through oxygen scavenging. Using the same concept as getter materials, the atmosphere is scavenged of free oxygen allowing for the fuel to react exclusively with the solid oxidizer.     

分析测试新成果(230~237)2种常见燃油添加剂对汽油燃烧烟尘的影响

采用气相色谱-质谱(GC-MS)联用技术,根据汽油原样中的特征成分,对未加入和分别加入汽油燃油精、海龙燃油宝的汽油燃烧烟尘进行对比分析.结果表明,汽油燃油精的加入会使汽油燃烧烟尘中各类特征成分的百分含量有所变化,但对谱图和特征成分的影响较小;而海龙燃油宝的加入对汽油燃烧烟尘的谱图、特征成分及其个数、各类特征成分的百分含量均产生较大影响.结果为火灾物证鉴定提供一定的参考依据.     

Gas-potentiometric method with solid electrolyte oxygen sensors for the investigation of combustion

Gas-potentiometric analysis using oxide-ion-conducting solid electrolytes as stabilized zirconia is a worthwhile method for the investigation of combustion processes. In the case of gas and oil flames specific parameters like the flame contour, the degree of burn-out and mixing can be determined and information about flame turbulence and reaction density can be gained from the temporal resolution of the sensor signal. Measurements carried out with solid electrolyte oxygen sensors in a fluidized bed show that combustion processes of solid fuels are also analyzable. This analysis results in fuel specific burn-out curves finally leading to burn-out times and to parameters of a macrokinetics of the combustion process as well as to ideas about the burn-out mechanism. From the resulting constants of the effective reaction rate a reactivity relative to bituminous coal coke can be given for any solid fuel.     

F-T柴油在直喷式柴油机中燃烧与排放特性的研究

煤通过Fischer-Tropsch (F-T)合成可得到十六烷值高、硫和芳香烃质量分数极低的F-T柴油。研究分析了未作改动的单缸直喷式柴油机燃用F-T柴油时的燃烧和排放特性。结果表明,与燃用0号柴油相比,燃用F-T柴油时的滞燃期平均缩短18.7%,预混燃烧放热峰值降低26.8%,扩散燃烧放热峰值较高,燃烧持续期相当。燃用F-T柴油时的最高燃烧压力略低,最大压力升高率显著下降,机械损失和燃烧噪音较小,燃油消耗率和热效率都得到显著改善。燃用F-T柴油可同时降低CO、HC、NOx和炭烟排放,其中NOx和炭烟分别平均降低16.7%和40.3%。研究表明,F-T柴油是柴油机良好的清洁代用燃料。