高变质无烟煤催化气化动力学及补偿效应

以碳酸钠为催化剂,利用热天平研究了福建建欣高变质无烟煤常压下水蒸气气化反应动力学,在800～950℃测定了碳酸钠加载量从0～18%时该无烟煤气化反应特性,确定了实验条件下碳酸钠催化剂加载饱和浓度,结果表明,加载催化剂后建欣无烟煤气化反应活化能大幅降低.得到了建欣无烟煤与水蒸气气化反应动力学缩芯模型,并给出相应的动力学参数.分析表明,该催化气化反应体系活化能E与频率因子A0之间存在动力学补偿效应,得出其补偿效应方程为ln,A0=8.66×10-5E-0.2827,等动力学温度为1 389 K.     

有机钠催化剂对无烟煤的催化气化动力学

以十二烷基苯磺酸钠和柠檬酸三钠为催化剂,利用常压热分析仪对福建省创宏无烟煤进行了水蒸气气化动力学实验.在850～950,℃下测定了催化剂加载量为0～15%时,转化率随气化时间的变化;并采用缩核模型对实验数据进行拟合,给出相应的动力学参数.结果表明,十二烷基苯磺酸钠和柠檬酸三钠均能明显提高反应的气化速率,降低气化反应活化能;表面活性剂十二烷基苯磺酸钠的催化效果优于络合剂柠檬酸三钠,且与碳酸钠催化效果相当,是一种良好的煤催化气化催化剂.     

中国典型无烟煤焦水蒸气汽化活性及动力学研究

以水蒸气为汽化剂,采用热重方法,在920～1050℃条件下,研究了6种典型中国无烟煤焦的水蒸气汽化特性．结果表明,6种无烟煤焦水蒸气汽化反应的活性与无烟煤的煤化程度相对应,即煤化程度越大,无烟煤与水蒸气反应的活性越小．无烟煤焦汽化结果用缩核反应模型描述较为理想,其活化能值在213～250kJ／mol范围;活化能与指前因子存在着动力学补偿效应．     

纸浆黑液为催化剂的高变质无烟煤水蒸气催化气化的热重与在线质谱研究

以纸浆黑液为催化剂,用热天平的等温法研究高变质无烟煤常压纯水蒸气催化气化反应。通过热重曲线和在线质谱分析解释纸浆黑液催化气化机理;为扣除纸浆黑液中固形物对气化过程的影响,对纸浆黑液和以纸浆黑液为催化剂的无烟煤进行等温实验,通过在线质谱确定了升温段热解与恒温段气化的产物,并得出了消除纸浆黑液影响的煤转化率的计算公式。     

典型农业生物质催化气化反应动力学特性研究

以CaO、MgO和Fe2O3为催化剂,用程序升温热重法对典型农业生物质催化气化特性及反应动力学进行了研究.利用均相反应模型和缩核反应模型对转化率与温度的关系进行了拟和计算,得到了谷壳样在4种不同二氧化碳气化条件下热解阶段及焦炭气化阶段的活化能和指数前因子.结果表明,在820～1000℃区间内,添加CaO的谷壳样表观活化能比谷壳的大;而添加MgO和Fe2O3的谷壳样表观活化能与谷壳的相比,分别下降了32.6%和17.9%以上,可以看出3种催化剂催化活性大小顺序为MgOFe2O3CaO,活化能区间范围为15.25～123.74kJ/mol.研究表明在低温区间(热解阶段),反应机理更趋向于均相反应模型,而在高温区间(气化阶段),反应机理更趋向于缩核反应模型.最后给出了谷壳在热解阶段及焦炭气化阶段的反应动力学方程.     

准东煤气化动力学模型研究

混合准东煤原煤与催化剂K_2CO_3、Ca(OH)_2并制成煤样,在化学反应动力学控制条件下研究其气化反应特性,分析了煤样质量、CO_2体积流量和颗粒直径对气化过程中内、外扩散阻力的影响,获得不同反应温度下均相模型、未反应芯收缩核模型和修正体积模型的拟合曲线,利用等转化率法计算气化反应活化能,并通过催化活性指数验证了该方法计算活化能的准确性.结果表明:在转化率为0.2、0.4、0.6和0.8时对应的活化能为100.1~130.2kJ/mol,3种模型计算所得活化能分别为128.97kJ/mol、140.33kJ/mol和139.43kJ/mol;均相模型为较合适的气化反应动力学模型.     

CaO和Fe(NO_3)_3催化锦界煤焦-CO_2气化反应的实验研究

分别以分析纯CaO和Fe(NO_3)_3·9H_2O为催化剂前驱物,在自建的固定床实验台上研究了常压下碱金属Ca、过渡金属Fe对锦界烟煤煤焦-CO_2等温气化的催化效果。实验结果表明:锦界煤焦的气化活性随Ca和Fe添加量的增大而提高,Ca和Fe的负载饱和度均为3%,在900℃气化温度下Ca金属的催化活性与Fe金属相当;Ca和Fe分别使气化温度降低120℃和90℃;在化学反应控制区域内,采用均相模型计算得到气化反应活化能、指前因子和反应速率常数等动力学参数,添加Ca和Fe金属后的煤焦气化速率常数提高近三倍,活化能基本没有变化。     

生物质催化热解气化热重分析研究

采用热重分析与气相色谱分析(TG-GC)相结合的方法,开展了以麦秸为主要研究对象的生物质催化热解气化实验研究,探讨了以NiO和CaO为催化剂,水蒸气气氛下的麦秸挥发分析出特性、半焦的气化特性、气化反应动力学特性以及催化剂对麦秸气化产物的影响.实验结果表明麦秸水蒸气气氛下的反应活性明显提高,气化反应过程中热解阶段视为一级反应,半焦气化视为缩核反应.非催化条件下麦秸的半焦气化在800℃以上才进行,添加NiO与CaO均促进了麦秸与水蒸气的气化反应,提高了气化过程的碳转化率和反应速率,但二者对半焦气化的促进机理以及气体产物的催化选择性有明显差异.添加NiO时H2产率最大,达到34mol/kg麦秸,且使气化反应温度明显降低.添加CaO不仅促进了H2和CO的生成,而且CH4产率也明显提高,表明CaO更有利于大分子碳氢化合物的裂解.     

煤灰对石油焦水蒸气气化的影响

通过热天平实验，研究了煤灰存在时石油焦的水蒸气气化反应行为．实验研究发现，煤灰对石油焦水蒸气气化反应活性具有较好的催化作用，而且催化作用的好坏受煤灰添加均匀性的影响．煤灰含量增加，石油焦气化反应速率增加；在煤灰含量较小时，煤灰含量的变化对反应速率的影响较大．但随着煤灰含量增加，煤灰含量的变化对反应速率的影响逐渐不明显．煤灰的存在降低了石油焦气化反应的反应活化能．     

松木屑水蒸气催化气化制氢及其大物料量气化动力学研究

利用松木屑在自制固定床气化系统上进行水蒸气催化气化实验研究.考察反应温度、水蒸气/生物质比(S/B)以及催化剂加入量对气体成分、产氢率和潜在产氢率的影响.结果表明:反应温度为850℃、S/B为3.27、催化剂量,木屑进料量比为2%时合成气品质较优,氢气浓度可达40.13%,产气率为0.718m3·kg-1.该文也进行大物料量松木屑催化气化等温热重实验研究,加入催化剂使木屑气化反应活化能降低,加快了反应进程.     

小型锅炉烟尘测试时锅炉出力的计算

锅炉烟尘测试时,必须对锅炉出力进行测试。但监测中,许多小型锅炉往往不具备相关的计量装置和仪表,为解决这一问题,文章提出了用烟气量和空气过剩系数来计算锅炉的出力的公式,在实际使用中,该方法简单易行,其结果和实测值具有很好的一致怀。     

Unerroric of control of mutual compliance of the efficiency of hydrogen engines of unmanned vehicles in the conditions of mass production

The issues related to the reliability of hydrogen engines of unmanned vehicles and increasing the efficiency of using hydrogen as fuel when using the method of its production during the decomposition of hydrogen-containing molecules of liquid-phase organic compounds in a plasma discharge under the action of intense ultrasonic exposure are considered. Experiments have shown that as a result of decomposition in the acoustoplasma discharge of liquid hydrocarbons, solid-phase carbon-containing products are formed, chemical transformations occur in the liquid phase and hydrogen-containing combustible gas is formed. Hydrogen-containing gas can be used as fuel immediately after synthesis, i.e. it does not require separation, since in addition to hydrogen it contains only impurities of CO₂ and water vapor. The purpose of the study is to formalize the basic conditions for tightening the control of mutual compliance with the efficiency of hydrogen engines of the same series in the conditions of their mass production. Methods of mathematical statistics and hardware-software modeling were used in the study. The term “unerroric of quality mutual compliance control” is introduced to describe a set of hardware and software tools for such control. The principle of in-depth testing of the technical condition of such engines of one series is described in a multidimensional formulation of the quality control problem for three of their operating parameters at once. The conditions for increasing the mutual correspondence of the measured values of such parameters in the conditions of serial production of hydrogen engines are formalized.     

中国煤炭地下气化技术的发展

本文综述了煤炭地下汽化技术的国内外发展现状,对我国“长通道、大断面”煤炭地下气化新工艺给予了技术经济评述,并提出了发展煤炭地下汽化技术的政策建议。     

Review of theory of distortion and disintegration of liquid streams

Linear and nonlinear analyses of the instabilities and distortion of liquid streams injected into a gaseous media are discussed. The various fundamental mechanisms and the predictive capabilities for the distortions are emphasized. Round jets, planar sheets, annular sheets, and conical sheets are discussed in detail. The balance between capillary and inertial forces is primarily examined. The method for simplifying the analyses in the case of thin liquid sheets is discussed. The capabilities for representing the droplet size distribution that follows the stream disintegration are outlined.     

MgO膨胀剂细度对MgO水化和水泥浆体膨胀的影响

基于《水工混凝土掺用氧化镁技术规范》中的Ⅰ型氧化镁（MgO）,研究了该型MgO膨胀剂（MEA）细度对掺粉煤灰水泥浆体膨胀性能的影响。即采用X射线衍射分析(XRD)及同步热分析（TG DSC）分析了掺MEA水泥浆体中MgO的水化性。结果表明,养护温度相同时,MEA的细度对水泥浆体内MEA中MgO的水化和水泥浆体的膨胀无显著影响,产生的膨胀均能补偿水泥浆体的收缩;MEA的细度可从试验设计采用的45 μm筛筛余15%左右增加到30%左右,这将有利于MEA生产企业的节能降耗。     

机车车轮多轴疲劳强度安全评定的研究

使用ANSYS8.0软件对高速列车车轮进行了三维有限元分析,计算出车轮在直线、曲线和道岔条件下牵引、制动共6种工况时孔边薄弱部位的应力,分别通过Mises等效平均应力方法、Sines平均主应力方法和应力分量中考虑平均应力方法计算出应力在极值位置时的等效应力幅、等效平均应力,从而进一步算出车轮的安全系数,对其疲劳强度进行评定,并对3种方法进行了比较研究。     

Constructal optimization of the geometry of an array of micro-channels

This paper documents the geometric optimization of an array of circular and non-circular ducts. The optimization was carried out numerically using finite volume method. As optimal dimensions were independent of the array configuration, the numerical simulation was performed on a unit cell. Numerical optimization for circular, square and isosceles right triangle cross-sections of channels was performed. Based on the results of this investigation, some correlations were proposed to predict the optimal hydraulic diameter and dimensionless heat transfer per unit volume. In addition to examining the effect of pressure drop on these parameters, it was showed that among the different geometries of this study, square cross-section has the most efficiency for a given volume. The numerical results of the present study were compared with approximate results reported in the literature which a good agreement was observed.     

固体热辐射Yong性能分析

本文对漫灰均温物体在常物性条件下对外辐射传热的Ｙｏｎｇ值计算建立了数学模型。通过与物体内能Ｙｏｎｇ公式的数值计算比较,得出了辐射能量的Ｙｏｎｇ值不大于内能Ｙｏｎｇ值的结论。从初步的热射Ｙｏｎｇ值计算公式发现。Ｙｏｎｇ与物体表面辐射率有关。     

Measurements of concentration distribution of hydrogen jet using deflection of center of the laser spot

The main purpose of this work is to propose a new method to evaluate the concentration distribution of the hydrogen jet by using a He–Ne laser through the jet. This research attempts to apply the expression of concentration Gaussian distribution, the refraction formula of inhomogeneous refractive index medium, and the concentration inversion function to disclose the displacement of the center of the laser spot at different heights in the gas jet. The spot images of the laser beam passing through the gas jet at three vertical heights z = 10d, 20d, 30d, and different radial positions are obtained. The radial spatial asymmetry of the gas jet is also found in the experiment. Finally, the calculated concentration distribution curve and the fluent simulation curve, it is found that the two results are very similar. Our findings show that the error between the concentration distribution of this method and the simulated concentration distribution reaches 2.43%.     

Heat of vaporization of mixtures

General expressions for the heat of vaporization of mixtures at constant pressure; at constant temperature; and at constant pressure, temperature, and composition are proposed. The last one is related to the liquid-vapor interface where steady vaporization or condensation is taking place. Numerical examples by the proposed expressions are shown for binary mixtures of HCFC22(R22) and (HCFC123(R123) © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(1): 12–24, 1996