农林废弃物制成型炭生产过程对环境的影响

作者对用农林废弃物制成型炭的生产过程对环境的影响进行了详细的研究分析,研究表明,本技术对周边环境的污染较小,开发利用本技术对充分利用农林废弃资源,提供清洁能源具有重要意义和良好的前景。     

煤催化加氢气化研究进展

煤加氢气化制天然气技术具有工艺路径短、热效率高等优点,其应用基础研究备受关注。但煤中存在部分致密的芳香碳结构,加氢反应性较差,即使在苛刻的反应条件下(~1 000℃、~7 MPa H_2),仍难以转化。通过引入催化剂,进行煤催化加氢气化可在温和的反应条件下实现煤的碳转化率和CH_4收率的同步提高。论述了碱金属(K、Na等)、碱土金属(Ca)和过渡金属(Fe、Co、Ni等)催化剂对模型碳加氢气化的催化作用原理。探讨了反应温度、氢气压力、和碳结构对C-H_2催化反应的影响规律,分析了适用于原煤催化加氢气化的最佳催化剂及工艺条件,并从CH_4和轻质液体焦油等产物生成规律、煤中碳结构随着反应进行的衍变过程等角度,讨论了催化剂分别对煤加氢热解和热解半焦加氢气化的催化作用行为。提出了煤催化加氢气化联产CH_4和轻质液体焦油技术从基础走向应用的进一步研究建议。现有研究结果表明,过渡金属与碱土金属组成的二元催化剂(Fe/Co/Ni-Ca)对煤加氢气化的活性较高。过渡金属元素在反应过程中主要提供C-H_2反应所需的活性氢,并削弱C—C键的键能;碱土金属元素Ca主要促进Fe/Co/Ni的分散,防止其发生硫中毒失活,并增强Fe/Co/Ni与碳之间的相互作用。温度升高一方面为化学键断裂过程提供了更高能量,加速C-H_2反应,另一方面促进催化剂在煤结构中扩散,提升催化剂的供氢和断键效率。升高压力促进了活性氢的供应,同时CH_4浓度得到稀释,反应向生成CH_4的方向移动。以5%Co-1%Ca为催化剂,在850℃、3 MPa H_2反应条件下,30 min内可同时达到90.0%的碳转化率和77.3%的CH_4收率。Co-Ca催化剂在煤加氢热解过程中具有催化解聚和催化加氢的作用,提高焦油和CH_4收率,同时催化剂在煤加氢热解过程中对煤结构产生催化活化作用,使得生成的半焦具有较高的气化活性。煤催化加氢气化的机理研究目前仍处于推测阶段,另外,该技术气化剂、煤种的适应性,催化剂循环利用性能有待进一步阐明。     

煤的加氢气化研究

在固定床加压反应器和加压热天平上对五种中国气化用煤进行加氢气化试验，探讨了煤在氢气中的气化特性，以及气化条件对气化结果的影响。发现在气化过程中。各类产品气体的生成速率都随温度而变化。甲烷和乙烷的生成速率在600℃左右可达到最大值．在常压到6MPa的压力范围内，气化速率，转化率，甲烷产率都随压力的提高而增加，呈朗格谬尔吸附等温线形状。当压力高于2MPa时，煤气中(不包括H2)烃类化合物的含量达到或超过90%．在850-1000℃的气化温度下．某些煤焦的加氩反应表现活化能为100kJ／mol左右．建立了动力学模型，较好地拟合了各项实验结果．     

Catalytic activities of ion-exchanged nickel and iron in low temperature hydrogasification of raw and modified birch chars

Raw, HNO₃ oxidized and carboxymethylated birch woods loaded with nickel or iron by the ion-exchange method were carbonized at 500 °C in a flow of nitrogen, and the resulting chars were hydrogasified in a thermobalance to examine their reactivities below 700 °C. The amounts of ion-exchanged metals on raw char were too small to give high gasification reactivity. However, oxidized and carboxymethylated woods with increased ion-exchange capacity produced much more reactive chars. Both nickel and iron exhibited larger catalytic activities on carboxymethylated chars than on oxidized chars, because better metal dispersion could be achieved on carboxymethylated wood with its larger cation exchangeability. It was noteworthy that only 1 wt% loading of iron, as well as nickel, on carboxymethylated char was sufficient to attain a gasification of 90 wt% at 700 °C. It was also noted that the catalytic effect, up to 600 °C, of iron on the gasification of oxidized and carboxymethylated chars was larger than that of nickel. This is ascribed to two factors; greater catalytic activity of metallic iron formed during the gasification than that of nickel metal, and low ash level in the chars. Above 600 °C, however, serious loss of activity of the iron was observed in the absence of wood ash. This showed the different influence of wood ash on the catalysis of iron in the low and high temperature regions.     

Hydrogasification of bituminous and brown coals at 1273 K: Action of a nickel catalyst

Hydrogasification of a bituminous and a brown coal was carried out at 1273 K in the presence of nickel catalyst. The action of the catalyst during gasification was investigated using a scanning electron microscope. Contrary to what is found with steam gasification, most of the catalyst particles were spherical, due to the higher temperature. Some particles made pits and disappeared into the char matrix and others agglomerated with each other increasing the diameter of the particles significantly. Although the action of the catalyst on a brown coal was essentially similar to that on a bituminous coal, the catalyst was more homogeneously distributed over the char surface from the brown coal.     

固定床煤焦加氢气化制甲烷研究与开发

采用固定床反应器,在不同的反应温度(973 K~1 123 K)、压力(3 MPa~7 MPa)和制焦温度(973 K~1 073 K)下,分别研究了煤种、温度、压力和制焦温度对大同煤焦、西班牙煤焦和平顶山煤焦的加氢气化的影响;认为煤加氢气化过程分为3个反应阶段。实验结果表明,在高温、高压条件下,有利于促进甲烷的产率和提高碳转化率。     

高校实验室废液现状及处理方法

目前高校实验室排放的废液已经成了一种不容忽视的污染源。针对国内高校实验室排污现状,对实验室废液的来源、种类进行了分类,同时对不同性质废液的处理方法进行了论述。     

对羟基苯酚不对称双酯的合成及三废处理

合成了一系列高纯度的对羟基苯酚不对称双酯类液晶化合物,这类化合物具有较高的清亮点和较宽的向列相温度范围,比较适合在STN或TN液晶混合物配方中应用。同时还探讨了制备过程中三废的处理和再利用。     

利用废弃陶瓷材料制备莫来石轻质材料

为了回收利用废弃陶瓷材料,节约资源,以废弃陶瓷材料为主要原料,加入不同量的黏土(质量分数分别为15%、25%、35%),外加锯末和结合剂,经混料、成型、烘干后,1 200、1 250、1 300、1 350、1 400℃保温3 h热处理,然后检测试样的物理性能,并进行了物相和显微结构分析。结果表明,当废弃陶瓷材料与黏土的质量比为85 15,烧成温度为1 400℃时,试样的综合性能最优;由于热处理过程中发生了莫来石化,试样中的主要物相为莫来石;1 400℃热处理后试样的孔隙直径比1 200℃的大,基质结构也更加致密,由K2O、SiO2、Al2O3组成的液相也较多,因而使材料的强度增大。     

离子液体合成研究进展

按照合成原理和合成步骤简要地介绍了离子液体的几种常用合成方法,如季铵化法、复分解法、酸碱中和法、直接合成法和两步合成法.并且根据离子液体中阴离子的不同,将离子液体分为卤素类、酸性类、碱性类、过渡金属类、稀有元素类等,对现有的离子液体合成方法做了较为全面的综述.     

Synthesis of activated charcoal from saw-dust and characterization for adsorptive separation of oil from oil-in-water emulsion

The paper represents the synthesis process of charcoal from saw dust by chemical activation with different chemical agents like phosphoric acid, zinc chloride, and ferrous sulfate heptahydrate. The synthesized charcoal samples were analyzed by scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and BET surface analyser. The adsorption capacity of different charcoal samples was tested to separate oil from the oil-in-water emulsion. Effects of different parameters like adsorbent dosage, contact time and temperature on adsorption of oil from oil-in-water emulsion by synthesized charcoals have been investigated. Under optimized condition, the oil separation efficiency is more than 98%, though it also depends on the initial concentration of oil in the emulsion. Isotherm and kinetic study on adsorption of oil from oil-in-water emulsion have also been studied. Three widely applied isotherm models viz., Langmuir, Freundlich, and Temkin were used to analyze the experimental adsorption data. Different adsorption kinetic models were considered to model the experimental data. Thermodynamics parameters were also evaluated for the adsorption of oil onto the charcoal samples.     

煤直接加氢制甲烷研究进展

天然气资源短缺、低阶煤资源利用问题突出,开发新型、高效和对环境友好的低阶煤制甲烷工艺成为研究热点。本文分析讨论了以下几方面:温度、压力、催化剂、煤种和气化剂等因素对煤直接加氢制甲烷过程的影响;煤直接加氢制甲烷的反应机理和动力学;3种典型煤直接加氢甲烷化工艺的优缺点;本文作者课题组正在研究开发的低阶煤炭化脱氧、高活性半焦直接加氢制甲烷工艺及其特点。分析认为:以低阶煤(生物质)为原料进行加氢甲烷化生产代用天然气成为新的研究重点,其中又以新型、廉价煤加氢甲烷化催化剂的研制和新型甲烷化反应器的开发最为关键。     

Treatment of industrial liquid wastes by electrocoagulation: Experimental investigations and an overall interpretation model

The paper presents the results of experimental investigations of treatment of concentrated wastes by electrocoagulation using sacrificial aluminium (Al) anodes. Tests were carried out batchwise in an electrochemical cell with recirculation for various wastes of industrial significance: the technique was shown to allow efficient abatement of the suspensions with concentrations of dissolved Al ranging from 150 to . Hydrogen evolution and Al dissolution occurred with current yields over unity. Besides, the time variation of the COD largely depended on the nature of the waste treated: whereas the treatment proceeds regularly for latex suspensions, the COD abatement with oil and silica suspensions starts only after sufficient accumulation of Al (III) species in the media. We proposed a phenomenological model for prediction of the waste abatement in term of COD by complexation of the matter suspended by Al (III), and taking into account the “latency” period observed experimentally. The values of the parameters involved are discussed in relation to the suspension treated.     

农作物秸秆炭制备速燃炭的研究

以农作物秸秆炭为主要原料制备速燃炭,研究了秸秆炭与引燃剂的比例及成型方式对速燃炭性能的影响,结果表明,农作物秸秆炭与引燃剂质量比为4:3,块状成型方式制备的速燃炭性能较好,其燃烧热为 21289.76 J/g,且 24 g 该速燃炭燃烧时火焰持续 13 min 55 s,火星持续 113 min,燃烧残渣 13.19%。并通过燃烧实验表明, 24 g 速燃炭能使 50 mL 蒸馏水持续沸腾 17 min,且水温在60~80℃ 之间保持 90 min 以上。     

普通离子液体和功能化离子液体的合成研究进展

离子液体是在室温下为液体、具有离子特性的新型绿色溶剂,作为一类环境友好型的反应介质,在诸多领域有其独特的性质.综述了普通离子液体和功能化离子液体的合成研究进展,并对其前景进行了展望.     

室温离子液体的合成

离子液体以其良好的物理、化学性质,日益引起人们越来越多的关注。离子液体的合成成为研究离子液体性质和应用首先要解决的问题。本文简要介绍了离子液体的合成方法及一些功能化离子液体的合成。     

生物质炭粉成型工艺及燃烧性能

研究了炭粉压缩成型的工艺方法。通过选择合适的粘结剂使木炭粉、竹炭粉和稻壳炭粉压缩成型,经试验分析得到在木炭粉、竹炭粉和稻壳炭粉中加入粘结剂B的质量分数为6%、5%和4%。对制得的成型炭进行了真空高温热处理,显著提高了成型炭产品的固定碳含量,3种成型炭固定碳含量平均提高5%以上。测定了成型炭的燃烧特性,3种成型炭中以固定碳含量最高的木炭成型炭热效率最高,为35.2%;竹炭粉成型炭次之,为34.1%;固定碳含量最低的稻壳炭粉成型炭热效率最低,为26.3%。结果表明:在密实度接近的情况下,成型炭的固定碳含量是影响其热效率的关键因素。     

Chemistry of methane formation in hydrogasification of aromatics. 1. Non-substituted aromatics

The chemistry of the formation of methane in hydrogasification of such unsubstituted aromatics as benzene, naphthalene, phenanthrene, anthracene and biphenyl was studied using a flow tube. Temperatures varied between 800 and 1000 °C. Gases and benzene were analysed by on-line gas chromatography, the tar products being analysed by mass spectrometry. At short residence times up to 10 s, methane yields increase with decreasing stability of the aromatics; that is from benzene to naphthalene, phenanthrene and anthracene. As decreasing thermal stability also promotes carbon formation as a competitive reaction, the methane yields from the less reactive aromatics may exceed those of the reactive aromatics if the residence time is prolonged. In addition to thermal stability the position of the primary bond rupture is important because it determines the structure of intermediate products.     

苯胺生产技术进展

介绍了苯胺生产中先进的绝热硝化技术、液相加氢技术、三废治理技术。与等温硝化相比,绝热硝化反应器体积小,成本低,采用静态混合器,避免乳化现象,操控系统先进,开停车时间大大缩短;与气相加氢相比,液相加氢转化率高,催化剂不需再生,设备少,在线系线极高;同时三废治理实现了废气NOx的再利用,碱性废水的热解技术不需添加药剂,处理有毒物彻底,且无固体废渣产生。