比表面分析法研究劣质动力煤的燃烧特性

采用氮吸附法测定了六种不同煤阶的劣质煤及其在燃烧前（热重分析着火温度点前）和燃烧后（热重分析燃烬温度点后）的比表面、体积和孔径大小。发现煤样在燃前比表面、体积数据皆增大，微孔和大孔数目皆增多。燃烧过程中同时存在互相竞争的“开孔”和“闭孔”作用，导致燃后煤样的微孔和大孔数目有增有减。并应用模糊孔模型，结合热重测试结果，分析了不同煤样的着火和燃烬特性。

加氢催化剂载体工业生产中混合均匀度的测试方法

使用螺条式混合机混合制备了一种加氢催化剂载体,选择比表面积、堆密度、微量元素含量作为控制指标,建立了载体原料混合均匀度的测试方法。同时制备了另一种加氢精制催化剂载体和一种加氢裂化催化剂载体,进一步对比表面法和微量元素法在干混、湿混过程中的混合效果进行了验证。实验结果表明,比表面法测试原料干混过程中的混合均匀度具有普遍适用性,微量元素法可用于测定干混及湿混过程中含有特定元素原料的混合均匀度。EDS表征结果显示,犁刀式混捏机混合后载体中SiO2的平均含量为1.37%(w),接近于理论值,混合均匀度为98.52%;双轴式混捏机混合后载体中SiO2的平均含量为1.29%(w),混合均匀度为95.56%。

纳米镍粉的粒度分析

纳米材料的性质强烈依赖于其颗粒和晶粒的大小 ,测量纳米颗粒或晶粒尺寸无论从粉体制备还是从应用上都具有重要的意义。本文针对纳米镍粉进行了一系列粒度分析研究 ,包括SEM、TEM、激光粒度分析法、比表面分析法、X射线衍射法和X射线小角度散射法 (SAXS)。不同的研究手段得到的纳米镍粉的粒径不尽相同 ,比较各种研究手段得到的结果可以知道其准确程度 ,并且针对不同的分析要求可选择不同的方法。

动力用劣质煤燃烧特性研究（上）

用热重分析法采用不同升温速率研究了六种煤样的ＴＧ，ＤＴＧ，ＤＴＡ及Ｔ曲线，用基辛格法计算得到不同煤燃烧反应的活化能，该值的大小与挥发分及灰分含量的比值的变化趋势基本相同．研究了同生矿物和后生矿物对煤着火和燃烧的不同影响．同时发现在用比表面分析法得到的吸附等温曲线及比表面积、平均孔径和体积等数据与热重分析、矿物质分析数据间可建立合理的关联．提出评价煤燃烧反应特性时应综合考虑燃烧反应前提条件──氧气与碳充分接触，以及化学反应本质──碳反应的活化能．

Pore structure effects on the kinetics of methanol oxidation over nanocast mesoporous perovskites

Mesoporous LaMnO3 perovskite catalysts with high surface area were synthesized by using the recently developed hard templating method designated as ＂nanocasting＂.Ordered mesoporous silica designated as SBA-15 was used as the hard template.It was found that the surface area of the nanocast perovskites can be tuned（80–190 m2/g）by varying the aging temperature of the SBA-15 template.Nanocast LaMnO3 catalysts showed high conversion efficiencies for the total oxidation of methanol under steady state conditions,the one with the highest value of surface area being the best catalysts,as expected.Kinetic studies were performed for all of the synthesized catalysts.Rate constants were found to vary in accordance with the specific surface area of the nanocast catalyst which depends on the aging temperature of the parent template.From the rate constants obtained from experimental conversions at various space velocities（19500 to 78200 h〈sup〉–1）,values of activation energy and pre-exponential factor for the three nanocast LaMnO3 catalysts were determined by the linear regression of the Arrhenius plot.It is observed that the activation energy for all the catalysts remain constant irrespective of the variation in specific surface area.Further,a linear relationship was found to exist between the pre-exponential factor and specific surface areas of the catalysts indicating that the rates per unit surface area remains the same for all the catalysts.

Synthesis of Silica-Dispersed NiMo Hydrodesulfurization Catalysts

Silica-dispersed NiMo hydrodesulfurization catalysts were synthesized by the deposition-precipitation method. For comparative purposes, bulk NiMo catalysts were obtained by co-precipitation. The silica-dispersed NiMo catalyst had highly active metals content. Silica was employed to disperse active metals for full utilization of active components. The BET analysis showed that the silica-dispersed NiMo catalysts had a high surface area （147.0 m2/g） and pore volume （0.27 mL/g）, whereas the bulk NiMo catalysts exhibited a very low surface area （87.5 m2/g）. Transmission electron microscopy results proved that the active components were dispersed on the SiO2 substrate. X-ray diffraction patterns of the silicadispersed NiMo catalyst and the bulk NiMo catalyst were indexed to NiMoO4. The hydrodesulfurization activity of silicadispersed NiMo catalysts was much higher than that of reference catalysts and could be up to twice greater than those of commercial NiMo alumina-supported systems per gram of catalyst. The activity testing results also demonstrated that the silica-dispersed NiMo catalyst was an effective hydrodesulflarization catalyst.

硅溶胶粒径测定法的探讨

硅溶胶是SiO2水溶胶和硅酸水溶胶的简称，是水化SiO2微粒分散在水中的胶体溶液，通常分碱性和酸性两大类：在这两类中又可按实际应用和SiO2浓度分成若干品种。目前国内主要生产碱性钠型硅溶胶，SiO2浓度一般在20—30％。