羧甲基羟丙基瓜尔胶合成新工艺及性能

为解决羧甲基羟丙基瓜尔胶(CMHPG)合成过程中副产物多,容易糊化的问题.以丙酮为反应介质,甲醇钠为催化剂代替乙醇、异丙醇为介质,氢氧化钠为催化剂.探讨了工艺条件对产品的影响,找出了较佳工艺条件.结果表明,合成较佳工艺条件为:环氧丙烷与瓜尔胶质量比为0.2∶1、氯乙酸与瓜尔胶质量比为0.4∶1,反应时间为160 min;前者催化剂与瓜尔胶质量比为0.2∶1、反应温度为45～50℃,后者催化剂与瓜尔胶质量比为0.3∶1,反应温度为65～ 70℃.乙醇、异丙醇为介质,氢氧化钠为催化剂合成产品的羧甲基取代度为0.43,羟丙基取代度为0.36,粘度为1 120mPa·s;以丙酮为反应介质,甲醇钠为催化剂合成产品羧甲基取代度为0.48,羟丙基取代度为0.37,粘度为1 030 mPa·s.     

以PCL-PEG为载体的人参皂苷Rg3纳米粒的制备及表征

以PCL-PEG为载体,采用乳化溶剂蒸发法制备人参皂苷Rg3纳米粒,以包封率和载药量为指标,通过正交实验优化制备条件。结果表明,最优制备条件为:人参皂苷Rg3浓度为3 mg/mL,PCL-PEG浓度为5 mg/mL,胆酸钠的体积为5 mL,胆酸钠浓度为0.5%。得到的纳米粒为球形,表面圆整光滑,粒径为129.1 nm,电位为-38.7 mV,包封率为90.03%,载药量为34.18%,稳定性良好,具有明显的缓释性能。     

新型起泡剂LZ的研制及评价

以ABS为起泡剂,HEC为稳泡剂,PESA为阻垢剂,咪唑啉季铵盐为缓蚀剂,制成新型起泡剂。实验结果表明,其缓蚀率为87.5%,阻垢率为98%。起泡剂受温度影响较大,温度为90℃时,泡沫的体积为370 mL,半衰期为6 min;泡沫性能受凝析油影响较小,受矿化度影响较大,当矿化度为8 000 mg/L时,泡沫体积仅为250 mL;气体流量为2.5 L/min时,携液率达28%。     

固体酸催化合成乙酸苄酯

以冰醋酸和苄醇为原料,硫酸氢钠为催化剂催化合成乙酸苄酯,其优化条件是：当酸的用量为0．1mol时,醇酸摩尔比1．9：1,催化剂为0．05g,带水剂环己烷为6mL,反应温度为95～120℃,反应时间为45min,酯化率为97．3％。     

一次风机电流与风压异常波动的分析及处理

我公司2条2 500t/d生产线回转窑规格均为Ф4.0m×60m,烧100%无烟煤。一次风机均为ZMH4-200罗茨鼓风机,排气压力为29.4kPa,流量为75.6m^3／min,转速为1450r／min,电动机为变频调速三相异步电动机,电压为380V,功率为75kW,额定电流为140A。     

课程改革中的三个“中心”的转变

通过对精细化工专业开展的课程改革研究,围绕由以教师为中心转变为以学生为中心,由以课本为中心转变为以“任务”为中心,由以专业技能为中心转变为综合职业能力为中心,进行教学组织与实施。     

氧化-酯化-MMA接枝复合变性木薯淀粉的合成与表征

以木薯淀粉为主要原料,经双氧水氧化、邻苯二甲酸酐酯化,再与甲基丙烯酸甲酯进行接枝合成出复合变性淀粉。实验得到较佳的反应条件为:氧化反应时间为2h,温度为40℃,氧化剂用量为5mL,酯化反应时间为4.5h,温度为45℃,催化剂用量为4%;接枝反应的接枝时间为4.0h,温度为40℃,投料比(MMA∶酯化淀粉)为1.75∶1,引发剂浓度为0.05mol/L。用红外光谱(FTIR)、扫描电镜(SEM)对原料和复合变性薯淀粉的结构进行了表征。     

过氧化氢漂白稻草纤维素实验条件初探

以预处理后的稻草纤维素为原料,以白度为指标,以过氧化氢为漂白剂,硅酸钠为稳定剂,分别考察了漂白次数和稳定剂用量对指标的影响,结果表明,以质量分数为3％的硅酸钠为稳定剂,两段漂白效果最佳。最佳二段漂白条件为：一段：过氧化氢浓度为3％,温度为70℃,反应时间为60 min, pH为10～11;二段：过氧化氢浓度为5％,温度为70℃,反应90 min, pH为10～11,在该条件下稻草纤维素白度最佳,为74．3。     

用褐煤活化一步法制备活性炭的研究

介绍了以褐煤为原料,磷酸为活化剂,硫酸为添加剂,采用炭活化一步法制备活性炭的实验,讨论了浸渍温度、炭活化温度、炭活化时间、磷酸的浓度、磷酸溶液与褐煤的液固比、硫酸的用量等主要因素对活性炭性能的影响。结果表明,适宜的工艺条件为:浸渍温度为80℃,炭活化温度为400℃,炭活化时间为60min,磷酸质量分数为40%,磷酸溶液与褐煤的液固比为5:1,硫酸的用量为褐煤质量6%。在该适宜的工艺条件下制备的活性炭,强度为88.2%,比表面积为1 158.6 m2/g,吸碘值为946.5 mg/g,吸亚甲基蓝值为203.4mg/g。     

纳米微乳化薄荷香精的制备及应用研究

采用纳米微乳化技术,经单因素和正交试验筛选得到了优化的制备工艺。得到优化制备条件为：在30℃恒温水浴下,薄荷油载量为12%（质量分数,下同）,乳化剂用量为12%（其中T20为10%,P1570为2%）,助乳化剂PG用量为20%,PEG-400用量为5%,去离子水为51%,剪切乳化速度为5 800r/min。产品理化指标为：外观澄清泛蓝光,水溶性良好,为O/W型微乳,粒径≤100nm,相对密度为1.0270,折光率为1.3944,薄荷油实际载量为（11.0±0.5）%,30℃时包封率为90%,在60℃条件下较稳定。     

煤炭地下气化高温井筒温度场研究

基于井筒与地层的传热情况,根据能量守恒及井筒传热原理,考虑物性参数随温度和压力变化,建立了生产井井筒的温度场预测模型,形成了求解算法和数学仿真模型,研究了温度场的影响因素。结果表明:产出气各物性沿井深分布差异较大,在分析时有必要耦合考虑;随着日产量和井底温度增加,井筒各段的温度均上升,其中日产量在30×10⁴ m³/d时,井口的产出气温度最高(686℃),井底温度在1000℃时,井口温度为588℃;井底压力对温度场影响很小,在工程应用中可忽略不计;随着井深增加,井口温度下降。     

晶须长径比对复合材料力学行为影响的模拟

在单向晶须增强树脂基复合材料的轴对称模型和已有研究成果基础上,利用有限元分析方法,研究该类复合材料中晶须长径比的变化对材料整体力学行为的影响.结果表明:1)晶须长径比对晶须应力作用明显大于对基体的影响;2)晶须的长径比h/r≤30时,随着晶须长径比的增大,发生在晶须端部处的集中应力急剧增加;但当长径比h/r≥30时,长径比的进一步增加对集中应力影响不大;3)随着晶须长径比的增大,界面剪切应力减小,分布曲线下移;但当长径比h/r≥30时,长径比的进一步增加对剪切应力影响不大;4)随着晶须长径比的增加,复合材料的拉伸强度逐渐增大.     

The service of the hearths of arc furnaces for melting stainless steels with the use of oxygen

Conclusions During the operation of arc furnaces specializing in the melting of stainless steels, chemical and phase changes occur in the magnesite hearths which lead to the formation of a single type structure in the monolith of rammed layer and upper courses of the structure.Petrographic studies showed that the monolith was formed as a result of phase inversions of the minerals of the hearth under the influence of the silicate constituents of the slag being produced, which partly settles to the bottom after discharge of the melt. These inversions greatly affect the physicochemical properties of the hearth and especially the refractoriness. The inversions which increase the refractoriness include the process of recrystallization of the periclase and chrome-spinel with the formation of strong and dense periclase-spinel growths in the upper layers of the hearth.The reduction in the refractoriness occurs owing to the formation of montichellite under the influence of calcium slag constituents and the gradual replacement of the forsterite by this silicate, and also the partial solution of periclase in the silicate melt.The thermal resistance of the hearth is favorably affected by the fact that the new silicate formations are distributed irregularly over the height of the hearth, and the nature of the distribution depends on their fluidity and temperature gradient in the hearth. In view of this consistency, the most refractory silicates, such as forsterite and mervenite, are localized in the upper strata of the hearth, and the montichellite, being the most fusible silicate, migrates to the lower layers.The result of all the processes and phase inversions taking place in the hearth is that the refractoriness of the most important layers of hearth (upper and middle) remains high during service. The reduction in refractoriness in the lower layer cannot greatly affect the life of the hearth since this layer is quite far away from the working region of the furnace and is in the low-temperature region.Large amounts of metals are detected only in the part of the hearth located in direct contact with the furnace bath; metal does not take a large part in the processes occurring in the hearth.The positive influence of the additions of chromite on the life of the hearth of electric furnaces determined during operation, can be explained by the fact that the chromite is essential for the formation of refractory chromespinel phases [2], contributes to the formation of periclase-spinel growths in the upper parts of the hearth, and accelerates the process of removing the less refractory silicates from the upper layers of the hearth to the lower [3].     

直缝式燃烧器W火焰锅炉新型二次风箱特性研究

为解决直流缝隙式燃烧器W火焰锅炉原设计的全通二次风大风箱由于锅炉炉膛宽度宽、风箱截面尺寸大等原因产生的炉膛中部缺风问题,华能上安电厂将4号锅炉原风箱改造为分隔型新型二次风箱。新型二次风箱改造完成后对其特性的试验研究表明,常规冷态通风时拱上、拱下各喷口及各风道区域之间风速偏差较小。单侧送风机运行且联络门关闭时,送风机停运侧各喷口风速明显低于送风机工作一侧,但通过拱上、拱下二次风门的调整,能有效缓解由于单侧送风机运行带来的喷口风速偏差。单侧送风机运行联络门开启的情况下,3个风道区域平均风速的偏差与正常双送风机运行时差别不大。与改造前相反,锅炉运行炉膛出口氧量已呈现中间高两头低的趋势,适当调整二次风箱风门开度后炉膛出口氧量分布趋于均衡,说明改造后的二次风箱风门能有效调节炉内二次风配风进而改变炉膛出口氧量分布。通过二次风箱风门开度的适当调整,能有效降低SCR入口NOx浓度,保证锅炉经济环保运行。     

Effect of preparation conditions on the properties of microspheres prepared using an emulsion-solvent extraction process

Methylaluminoxane microspheres were prepared using a hydrocarbon-in-perfluorocarbon-emulsion solvent extraction process. The effect of the preparation conditions on the size of the microspheres was investigated. As expected, the size of the microspheres decreased with increasing stirring speed. At low surfactant concentrations the size of the microspheres was independent of the surfactant concentration. However, the size of the microspheres decreased as the surfactant concentration was further increased. The size of the microspheres was not only affected by the surfactant concentration but also by the volume ratio of the dispersed phase to the continuous phase. At a low volume ratio of the phases the effect of the surfactant on the size of the microspheres was larger than the effect of the increased volume ratio of the phases. At high volume ratios of the phases the effect of the volume ratio of phases on the size of the microspheres became more significant than the effect of the surfactant. A slow solidification increased the formation of non-spherical microspheres.     

The role of the symmetry and the flexibility of the anion on the characteristics of the nanostructures and the viscosities of ionic liquids☆

The transport properties of ionic liquids (ILs) are crucial properties in view of their applications in electrochem-ical devices. One of the most important advantages of ILs is that their chemical–physical properties and conse-quently their bulk performances can be well tuned by optimizing the chemical structures of their ions. This will require elucidating the structural features of the ions that fundamentally determine the characteristics of the nanostructures and the viscosities of ILs. Here we showed for the first time that the“rigidity”, the order, and the compactness of the three-dimensional ionic networks generated by the anions and the cation head groups determine the formation and the sizes of the nanostructures in the apolar domains of ILs. We also found that the properties of ionic networks are governed by the conformational flexibility and the symmetry of the anion and/or the cation head group. The thermal stability of the nanostructures of ILs was shown to be con-trolled by the sensitivity of the conformational equilibrium of the anion to the change of temperature. We showed that the viscosity of ILs is strongly related to the symmetry and the flexibility of the constitute ions rather than to the size of the nanostructures of ILs. Therefore, the characteristics of the nanostructures and the viscosities of ILs, especially the thermal stability of the nanostructures, can be fine-tuned by tailoring the symmetry and the conformational flexibility of the anion.     

纳米填料/橡胶体系在贮存中的结构形态变化Ⅱ.结构变化的影响因素及其对性能的影响

综述了纳米填料／橡胶复合体系在熔融态或高弹态贮存停放过程中,影响其结构形态变化的因素,以及贮存停放对复合体系流变性能、物理机械性能和导电性能的影响,并评述了相关的理论模型。纳米填料／橡胶复合体系在熔融贮存过程中的结构变化主要受橡胶的黏度、填料特性及其用量、填料与橡胶之间的相互作用以及加工性能的影响。填料网络结构的絮凝程度强化使复合体系流变性能、动态力学性能降低,但导电性能提高。相关的填料聚集动力学和填料絮凝模型大部分是唯象模型。     

复合材料风扇叶片榫头铺层设计及加工制造

碳纤维复合材料风扇叶片榫头段是铺层数量最多、递减铺层最集中的部位,榫头的铺层质量影响叶片的低周疲劳强度。为完成叶片榫头段的铺层设计,基于铺层设计准则,建立了一种适用于航空发动机复合材料风扇叶片榫头段铺层设计的方法。根据铺层高度大小将铺层分为结构层和插入层,在结构层铺层设计中考虑了高度递减层的角度与铺放位置。在插入层铺层设计中,考虑了单组插入层铺层数量、单组插入层内部铺层顺序及铺层角度、单组插入层形成的坡度、相邻插入层之间的错开距离等五个方面的因素,确定了单组插入层的结构及其在榫头的分布。根据设计方案对榫头进行加工制造,成型的榫头试样件厚度检测质量良好,证实了该铺层设计方法的可行性。     

转炉一次除尘新OG系统高效喷淋塔喷嘴布置方式对喷淋特性的影响

采用离散相模型对新OG系统高效喷淋塔入口段及主体段喷嘴的布置方式进行数值模拟,考察了喷嘴喷射方向和喷淋层数对雾化场气流分布和降温效果的影响。结果表明,喷嘴的喷射方向和塔内的喷淋层数对雾化场的气流分布和降温效果影响较大;喷淋塔入口段采用逆流喷射时,出口截面的速度分布最均匀且降温效果最好;高效喷淋塔的主体段的喷淋层数为5时,塔内烟气的速度流场较均匀,且中心区域的气流速度为2~4 m/s,有助于延长气体与液滴的作用时间;随喷淋层数增加,塔内温度梯度变化增大,水蒸气质量分数分布与温度分布对应,塔内的平均湍动能逐渐增高。     

聚丙烯气相反应器工艺参数的计算和控制

以液相本低聚合和气相聚合组合式聚丙烯（PP）装置生产多相共聚PP产品为例，推导出了多相共聚PP生产中气相反应器工艺参数之间的关系式，并讨论了工艺参数对产品性能的影响，通过控制气相反应器的乙烯进料量与气相比，改变产品的抗冲击性能，乙烯含量越高，产品的抗冲击性能越好，刚性越差，无定形二聚物的含量越高，产品的抗冲击性能越好，但刚性相对降低。