旋转闪蒸干燥器在碳酸钡干燥中的应用

介绍了河北诺达化工设备有限公司开发生产的旋转闪蒸干燥器代替回转圆筒干燥器在碳酸钡干燥过程中的应用.通过对投资、能耗、产品质量、环保效益的详细分析得出结论:用旋转闪蒸干燥器代替回转圆筒干燥器,具有节省投资,节约能耗,提高产品质量,减小环境污染等优势,为碳酸钡的干燥提供了一种新方法.该设备也适用于碳酸锶、硫酸钡、碳酸钙等滤饼类物料的干燥,同样对于冶金、化工、医药、食品等行业的滤饼类物料的干燥也具有极高的应用价值.     

冲击式旋转闪蒸干燥器

本文介绍了冲击式旋转闪蒸干燥器的设备结构及工艺流程，并通过对其干燥原理的分析，研究对流干燥过程的强化问题，从而探讨新型对流干燥器的开发途径。     

气流式旋转闪蒸干燥器

介绍了气流式旋转闪烁干燥器的特点,结构,流程,工作原理,主要操作参数及其应用。     

闪蒸干燥器在化工生产中的应用

介绍了闪蒸干燥器,并对它的工作原理以及设计使用作了一些探讨。     

旋转闪蒸干燥机在洗涤剂用4A沸石生产中的应用

介绍了旋转闪蒸干燥机的特点、基本结构和工作原理及其在应用中的常见故障、诊断和基本维护。与现有的强化沸腾干燥器相比,旋转闪蒸干燥机具有产能大、能耗低的优点,值得推广应用。     

旋转闪蒸干燥机在白炭黑干燥中的应用

简述了旋转闪蒸干燥机的工作原理，在白炭黑干燥中的应用和测试数据，归纳出干燥系统的设备配备对数，并与传统的干燥工艺及所获产品的主要指标相比较。     

旋转闪蒸干燥技术在漂粉精生产中的应用

研究了旋转闪蒸干燥技术在漂粉精生产中的应用、存在问题及对策。     

旋转闪蒸干燥器在糠醛渣干燥中的应用

介绍旋转闪蒸干燥器在糠醛渣干燥中的应用、干燥器的原理及其有关计算。     

载体流化床干燥器在重质碳酸钙生产中的应用

介绍了载体流化床干燥原理、特点、工艺流程及其在重质碳酸钙生产中的应用 ,并叙述了影响干燥过程的主要参数选择、装置的操作条件和干燥成品性能。     

木薯酒糟在旋转闪蒸干燥器中的干燥特性

对木薯酒糟在旋转闪蒸干燥器中的基本干燥特性进行了实验研究。结果表明该物料干燥后的含水质量分数与干燥介质温度呈直线关系 ,与干燥时间呈指数曲线关系 ,这一特性与其薄层干燥过程相似。某些研究结果还为该物料的工业化干燥提供了依据     

旋转闪蒸干燥机在碳酸钡行业的应用

对旋转闪蒸干燥机的工作原理、结构特点进行了详细介绍，并将转筒烘干机和旋转闪蒸干燥机进行了对比，提出碳酸钡行业采用旋转闪蒸干燥机可以把碳酸钡的成本降到最低限度，而产品质量可以得到很大提高。旋转闪蒸干燥机也可用于碳酸锶、硫酸钡等粘性物料的干燥。     

氧化铝干燥剂抗压破碎强度测量中的不确定度评定

根据GB3635-1983标准的要求,对某一牌号的干燥剂进行抗压破碎强度测试,并依据JJF1059-1999对该样品的抗压破碎强度测量结果的不确定度进行了评定,分析了对实验影响的各种因素。对该批样品的扩展不确定度UP=17.6 N/颗,真值为150.1~185.3 N/颗,置信概率为95%。实验证明:物性测试中应引入不确定概念,以表征被测量的真值所处量值的范围。     

氧化铝载体在草酸酯合成催化剂中的应用

介绍硝酸法制备氧化铝载体及其前驱体拟薄水铝石的影响因素,成胶温度、老化温度、老化介质、反应体系pH值等制备条件影响拟薄水铝石孔结构及比表面积。成胶温度和老化温度越高,老化时间越长,老化介质中加入碳酸氢铵等有利于提高拟薄水铝石结晶度,pH值主要影响拟薄水铝石晶形。拟薄水铝石制备过程中、成型过程中及成型后可通过添加助剂、扩孔剂、模板剂,采用水热处理和改变焙烧温度等方法调控氧化铝孔结构和比表面积。氧化铝载体的比表面积和孔结构影响草酸酯合成催化剂的活性和选择性。     

铅/氧化铝催化剂的制备研究

工业上应用最广的合成吡啶的催化剂是Pb/ZSM-5催化剂.研究了在铅/氧化铝(Pb/Al2O3)催化剂上的醛氨缩合生成吡啶的反应,考察了不同氧化铝载体、铅负载量、催化剂焙烧温度对催化剂性能的影响,并对催化剂进行了XRD表征.结果表明:在氧化铝载体比表面170～185 m2/g、孔容1.6～2.0 cm3/g、平均孔径34 nm,铅负载量在质量分数2.5%～4.0%,催化剂焙烧温度在500～550℃时,制备的催化剂性能最好,烷基吡啶的收率可达90%.     

On the catalytic effect of zirconia on flash sintering of alumina

Flash sintering of alumina is more difficult than of yttria-stabilized zirconia (YSZ). Whereas (MgO doped) alumina requires fields greater than 1 kVcm^–1 and temperatures often significantly higher than 1000°C, YSZ can be flashed sintered at ∼100 Vcm^–1 at temperatures below 800°C. Mixed powders of such bi-phasic ceramics, on the other hand, can be flashed under conditions below those for alumina. This effect is usually subscribed to the influence of YSZ on the overall electrical conductivity of the composite. However, such rationalization leaves open the mechanism by which YSZ catalyzes the flash event in alumina. Here, we present results for the onset of flash in a layered structure of YSZ and alumina where both constituents extend from one electrode to the other. We find that the flash initiates, at first, exclusively in the YSZ layer, under conditions identical to those in usual voltage-to-current experiments in single phase YSZ, and then, after a brief incubation period, spreads transversely through the thickness of the alumina layer at a speed of ∼3.3 mm s^–1, while the power supply is held at constant current. This observation opens a new question as to how flash once initiated in an “easy” phase can migrate normal to itself into a second ceramic, which is nominally more-difficult-to flash. (In the present experiments, the alumina layer sintered to full density with all the shrinkage being accommodated in the thickness direction, consistent with an earlier study that articulated that flash obviates constrained sintering.) It is noteworthy that the catalytic effect depends not only on the volume fraction of YSZ, but also on the architecture of the green state (for example a two-phase powder mixture vs. layered structure), which may affect the initiation of the flash in YSZ but, likely, not its migration behavior into the second phase.     

An excellent support of Pd catalyst for methane combustion: Thermal-stable Si-doped alumina

Thermal-stable Si-doped alumina was prepared by the reverse microemulsion method and was used as the support of Pd catalyst for the methane combustion. The physicochemical properties of Si-alumina and catalytic performance of Pd/Si-Al₂O₃ were characterized by XRD, N₂ adsorption, FT-IR, XPS and methane catalytic combustion. The results indicate that the presence of Si can increase the thermal stability of alumina and promote the coordination state of aluminum from tetrahedral to octahedral, but its content added should be controlled appropriately to 5–6 wt%. Si-doped alumina prepared by the reverse microemulsion method is an excellent support of Pd catalyst for the methane combustion, which can increase both the catalytic activity and thermal stability of the Pd catalyst. The studies also show that the calcination temperature of support affects remarkably the performance of catalyst, and the high thermal stability of support is very important to increase the performance of Pd catalyst for the methane combustion.     

氧化铝载体改性及其应用研究进展

氧化铝不仅价格低廉、易获取,且具有多孔性、大比表面积、高分散性、高热稳定性等优点,常用作催化剂载体,广泛应用于工业催化领域。氧化铝的孔结构对工业催化剂性能影响很大。为优化氧化铝载体的性能,对氧化铝的扩孔和添加助剂改性已进行了大量研究。扩孔改性可降低扩散阻力并改善传质、提高活性位点的有效利用率、增强抗结焦性能,进而提高加氢催化的产率;添加助剂改性可有效抑制氧化铝载体高温烧结和相变,防止孔结构被破坏,提高催化剂的寿命。本工作介绍了制备氧化铝的方法?拟薄水铝石脱水法和溶胶?凝胶法,综述了氧化铝的扩孔方法,总结了改性氧化铝载体的最新研究进展,包括自组装法、水热处理法、扩孔剂法;阐述了氧化铝添加助剂的改性方法,包括加入稀土金属氧化物、碱(土)金属氧化物、其它金属氧化物及非金属氧化物。最后,展望了氧化铝未来的研究和发展方向。     

A novel alumina catalyst support with high thermal stability derived from silica-modified alumina aerogel

A new alumina catalyst support with high thermal stability was synthesized. The high thermal stability was achieved through the synergetic effect of silica addition and the ultra-low bulk density (aerogel). The amount of silica was varied from 2.5 to 10 wt% and 5 wt% was found to be most effective for suppressing phase transformation; the θ phase remained even after heating at 1400°C for 1 h. The surface areas of the present alumina with 5 wt% silica were 86 and 36 m²/g after heating at 1300 and at 1400°C, respectively. This revised version was published online in November 2006 with corrections to the Cover Date.     

蒽醌加氢钯催化剂载体改性研究

针对Pd/Al2O3催化剂载体的改性进行研究,将1 000℃焙烧后的氧化铝粉末与未焙烧的活性氧化铝粉末按不同比例混合和焙烧制备载体,采用等体积浸渍法制得负载Pd的Pd/Al2O3催化剂。采用XRD、BET、NH3-TPD和HOT对载体以及催化剂进行表征,并考察催化剂的蒽醌加氢性能。结果表明,提高载体中焙烧后氧化铝粉末的比例,导致载体中γ-Al2O3减少和δ-Al2O3增多,载体酸性降低,Pd分散度变大,从而提高了催化剂氢化效率。当焙烧后氧化铝质量分数为40%时,分散度和活性表面积达到最大,晶粒度最小,氢化效率最高,催化活性最佳。