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设计了一种涡旋脉冲式反应装置,分析了气-液或气-液-固多相体系在涡旋脉冲式反应装置中的流动状态及特点。采用Ca(OH)2—H2O—CO2气-液-固反应体系考察了该涡旋脉动式反应装置的性能。实验结果表明,采用纯CO2气体或CO2气体含量为30%的混合气体均可以制备平均粒径为40-50nm的纳米CaCO3产品,比传统工艺制备的纳米CaCO3的平均粒径小,粒度分布更窄。 相似文献
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阐述了喷雾干燥条件对PVC专用树脂的黏度、挥发物、筛余物指标的影响。生产实践表明喷雾干燥塔出口温度约为55℃(当树脂含水量超过0.6%时干燥塔出口温度为55-56℃),气液比为7-9,能使树脂优级品率达到98.5%以上。 相似文献
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以氨气和硝酸锌为原料,在旋转填料床中通过气液反应制备前驱体氢氧化锌.经煅烧后可得超细氧化锌粒子,经XRD和FEM检测得到其粒径为20-80nm。重点研究旋转填料床转速、原料浓度、氨气分率、气液比等对前驱体氢氧化锌粒径的影响,选择洗涤条件及优化煅烧温度和时间.确定了旋转填料床气液反应制备超细氧化锌的最佳工艺条件。 相似文献
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对于气固相氢氟化反应制备七氟丙烷的催化剂,进行了系统的研究。采用浸渍法制备催化剂,当催化活性组分A为载体的8.5%~10%,组分C2为1.0%~2.5%、二者之和为11%时,达到了较佳的催化性能,将其应用于由六氟丙烯制备七氟丙烷时,在反应温度≥210℃时,粗品气中的F-227含量≥98.5%。 相似文献
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气升式环流反应器在不同体系下的循环液速和局部气含率 总被引:12,自引:1,他引:12
在气升式环流反应器中,分别研究了空气—水、空气-0.1%乙醇水溶液和空气-水-活性污泥体系中的循环液速以及气含率随操作条件的变化规律。实验结果表明,循环液速随着表观气速的增加而增大,不同体系中的循环液速差别不大;导流筒内、外不同高度处的局部气含率均呈自下向上增大的趋势,且导流筒内部气含率高于导流筒外部的气含率。体系的聚并特性对平均气含率和局部气含率有较大影响。 相似文献
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考察了催化剂壁载方式、涂层载体和Pd负载量对微通道内的硝基苯气-液-固三相催化加氢反应的影响以及其并行放大效应.结果表明,与溶胶-凝胶法相比,浸渍法制备的催化剂涂层性能较好,其转化率、选择性分别达到89.2%和93.8%;采用强酸性、大比表面积的载体有利于反应性能的提高;活性组分Pd负载量为2.00 mg,催化剂活性较... 相似文献
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以空气、水为工质,用双头电导探针研究了泡罩塔板上局部气液接触情况,得到了泡罩塔内距离塔板高度49mm截面上气液两相局部参数——气含率、气泡速度、比表面积及气泡尺寸的统计规律。结果表明,在泡罩塔板上,同一位置的局部气含率随气量的增加而增大,受液量的影响较小;气泡速度主要分布为0.4~o.6m/s;气液比表面积的值85%在50~200m^-1,但在截面上分布不均匀;气泡Sauter直径为0~40mm,55%分布在5~25mm。 相似文献
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目前,我国对煤系高岭土资源的整体深加工技术水平较低,导致了资源浪费和环境污染。本文分别以煅烧煤系高岭土和环氧树脂为原料和粘结剂,利用激光选区烧结工艺制备多孔煤系高岭土陶瓷,研究了环氧树脂含量对多孔煤系高岭土陶瓷性能的影响。研究表明,制备的多孔煤系高岭土陶瓷主要物相为莫来石和方石英,其孔隙分布均匀。随着环氧树脂质量分数从10%增大到25%,多孔煤系高岭土陶瓷素坯的抗弯强度由0.17 MPa增大到0.32 MPa,多孔煤系高岭土陶瓷的抗弯强度由2.81 MPa减小到0.82 MPa,其气孔率由50.37%增大到59.69%。以煤系高岭土为原料,采用激光选区烧结工艺制备多孔陶瓷对煤系高岭土资源的开发利用具有较为重要的意义。 相似文献
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Plate-like potassium magnesium titanate (KMTO) powder prepared by molten salt growth method and the KMTO porous ceramic synthesised by polymeric sponge replication method were used as sorbents to remove nickel ions from wastewater. Both powder and porous ceramic were characterised by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The maximum adsorption capacities of powder and porous ceramic were 96 and 24?mg?g??1 respectively at a pH value of 6 (25°C). However, the removal efficiencies of both could reach up to 99%. Moreover, the adsorption kinetics for the KMTO powder and the porous ceramics followed the pseudo-second-order kinetic model, and the equilibrium data for the KMTO powder fitted the Langmuir isothermal model well, while the porous ceramics fitted with the Freundlich model. The mechanism of the adsorption by the KMTO powder and the porous ceramic was ion exchange. It was also shown that the nickel saturated KMTO powder and the porous ceramics were stable in leaching tests. 相似文献
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随着洁净煤发电技术的发展及环保要求的提高,高温气固分离技术取得了重要的进展。本文阐述了在高温过滤材料方面,经过了早期的金属多孔材料、均质陶瓷多孔材料、纤维增强陶瓷复合材料、金属合金及金属间化合物多孔材料等四个阶段的探索,逐渐形成了陶瓷粉末、陶瓷纤维、金属粉末、金属纤维和金属丝网等多种高温气体过滤元件,催化与过滤复合元件近年来也逐渐得到工程应用。此外,在高温过滤元件表面粉尘层结构、脉冲反吹循环再生、高温过滤器结构设计及实时运行优化等方面都取得了重要的技术进展。目前,高温气体过滤技术及装备已在煤气化、催化裂化、冶金及垃圾焚烧处理等方面得到了广泛的应用,其适用的温度范围为260~650℃,压力范围从常压到6.0MPa,过滤效率达到了99.9%以上,可有效除净1μm以上的颗粒,净化后气体中的颗粒物含量低于5mg/m3。指出随着国家经济转型和环保排放要求的提高,高温气体过滤技术在产品质量升级、高温余热利用及颗粒物排放控制等领域具有更加广泛的应用前景。 相似文献
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本文以城市污泥和絮凝污泥为主要原料,石英和煤炭为辅料制备多孔陶瓷.通过均匀试验设计,系统研究各因素对多孔陶瓷性能的影响,找出回归方程和最佳工艺条件.多孔陶瓷制备的优化配方为:城市污泥为16.67%,石英为33.33%,絮凝污泥为25%,煤炭量为25%,煤炭颗粒为0.1 ~0.9 mm,转化时间为150min,烧成温度为1230℃.由最优配方所制备的多孔陶瓷的吸水率为57.2%,显气孔率为60.89%,体积密度为1.065 g/cm3,抗压强度为1.8 MPa,耐酸性为97.1%,耐碱性为98.3%. 相似文献
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本文成功开发了用于光固化成型的树脂基硅藻土浆料,系统探讨了分散剂种类、含量及固含量对硅藻土浆料流变特性的影响,并对其作用机理进行了分析,获得了用于光固化成型的高固含量、低黏度的硅藻土浆料,并采用3D陶瓷光固化设备制备了结构复杂的硅藻土多孔陶瓷。结果表明,BYK2009为硅藻土浆料的最佳分散剂,且当分散剂相对粉体质量为3%时,浆料黏度最低。成功制备出粉体体积分数为40%的硅藻土浆料,在剪切速率为30 s-1时,硅藻土浆料黏度为17.30 Pa·s。在900 ℃烧结时得到显气孔率为51.30%、抗弯强度为(46.28±2.63) MPa的硅藻土多孔陶瓷。本研究为光固化成型具有复杂多级孔结构的硅藻土载体提供了参考。 相似文献
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采用凝胶注模法制备了多孔羟基磷灰石陶瓷,探讨了制备工艺对陶瓷显微结构和力学性能的影响。结果表明,以柠檬酸三铵C6H17O7N3为分散剂,最佳加入量(以粉料质量计算)为2%,最佳的球磨时间为5 h,球磨时最佳的水/粉料的质量比为1.5∶1,球磨时的最佳pH值为10,在1 200℃下烧成了HA多孔陶瓷。单体浓度10%的样品在1 200℃下2 h烧成的陶瓷,开孔率为39.87%,抗压强度为83.60 MPa,抗折强度为0.059 2 MPa;单体浓度15%的样品在1 200℃下3 h烧成的陶瓷,开孔率为39.59%,抗压强度为83.92 MPa,抗折强度为0.062 6 MPa。 相似文献
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Hiroaki Katsuki Eun-Kyoung Choi Won-Jun Lee Kwang-Taek Hwang Woo-Seok Cho Sridhar Komarneni 《Journal of Porous Materials》2018,25(3):643-648
Porous ceramic plates were prepared from clay and wood charcoal powder at 900 and 1100?°C and their porous properties, water absorption and the cooling effect of porous plates were investigated to produce eco-friendly porous ceramics for cooling by the evaporation of absorbed water. Porous properties were dependent on the firing temperature, and total pore volume, average pore size and porosity, which were 0.38–0.39 cm3/g, 0.15–0.17 μm and 49–50%, respectively at 900?°C and 0.31–0.33 cm3/g, 2.47–2.59 μm and 43–44%, respectively at 1100?°C. By the addition of wood charcoal powder, the cooling rate of porous plate fired at 1100?°C was 1.7 times faster than that of the plate fired at 900?°C and the cooling temperature difference (?T) was around 2.3?°C at 22.5?°C and 52–54% of relative humidity and around 3.2?°C at 29?°C and 77–80% of relative humidity. The porous ceramic plates developed here are potential materials for cooling buildings. 相似文献
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Dechang Jia DongKyu Kim Waltraud M. Kriven 《Journal of the American Ceramic Society》2007,90(6):1760-1773
A novel kind of pore self-forming macro-/mesoporous gehlenite (2CaO·Al2 O3 ·SiO2 ) ceramic (abbreviated C2 AS) having a highest porosity of 80% corresponding to a volume expansion of 134% during sintering has been developed. The pore self-forming ability, microstructure, mechanical, and thermal physical properties of the porous ceramic are related to the sintering temperature. The gehlenite ceramic shows a very good pore self-forming ability over a very wide range of temperature from 900° to 1450°C. No vesicant is required and no hydrothermal treatment is needed, as is generally the case for other kinds of porous ceramics or glasses. The pore self-forming ability of the C2 AS porous ceramic can be attributed to the escape of the adsorbed water vapor during the sintering process, due to automatic hydration of the fine, amorphous, flakey-shaped starting C2 AS powder particles synthesized by the organic steric entrapment (PVA) method, as well as to their fine, porous microstructure. The pores of the ceramics can be either open or closed, and the average pore size ranges from 0.6 to 1.1 μm, corresponding to a porosity of 75%–80%, respectively. The porous ceramic can preserve nanometer-sized (26–50 nm) crystallites up to 1000°C. Sintered or thermally treated under different conditions, the porous ceramics exhibit relatively high flexural strengths ranging from 9.1 to 15.4 MPa, with a standard deviation of 0.3 and 4.2 MPa, respectively. Thermal properties of the porous ceramic up to 1000°C, including thermal expansion coefficient, thermal diffusivity, specific heat, and thermal conductivity, were investigated, and the stability of the porous ceramic in boiling water was also studied. 相似文献