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81.
鼓泡浆态床费托合成(FTS)的模拟:数值分析 总被引:6,自引:2,他引:4
建立了浆态床反应器模型,该模型考虑了气相、液相的轴向分散及催化剂沿床层的非均匀分布。通过与Rheinpreusen-Koppers示范厂文献实验数据的对比,检验了模型的有效性。依据模型,计算分析了反应物、产物的浓度分布,气液两相的H2/CO变化及FTS与WGS对合成气转化的贡献。模拟结果给出了浆态床为何能够利用贫氢合成气的合理解释 相似文献
82.
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84.
Rinaldo A. M. Vieira Leticia S. V. S. Su?é Carlos A. M. Pires Antonio O. S. Silva Marcelo J. B. Souza Antonio S. Araujo 《Reaction Kinetics and Catalysis Letters》2006,88(1):119-126
Summary The catalytic oxidation of phenol over CuZSM-12 (SAR = 200) has been studied using a semi-batch slurry reactor at temperatures
of 110; 120 and 130oC, and acidic neutral and basic pH. At 130oC, the phenol undergoes total conversion to carbon dioxide and water in 1.5 h. The kinetic parameters were evaluated using
a modified homogeneous-heterogeneous model for the experimental data. Using this modified model, the activation energy for
the catalytic oxidation process was ca. 90 kJ mol-1. 相似文献
85.
The conventional analytical HPLC was successfully developed for micro‐column separation by using a simple eluate splitting system, self‐preparation of packing column and on‐capillary column detector in our laboratory. Porous inlet frit in fused silica capillary was rapidly prepared by sintering stainless steel powders under 500 meshes for about 20 s. The use of such frits or metal meshes in capillary to retain C18 particles of chromatographic packing was demonstrated to be stable and specially robust with continuous packing and long chromatographic runs. Furthermore, the chromatographic behavior was detailedly evaluated by changing the flow rate and the percentage of mobile phase using the prepared capillary column. Under the optimal experimental conditions, baseline separation of the model analytes including thiourea, benzene, toluene, ethylbenzene was obtained with a high column efficiency near 70000N (plates/m) by the developed capillary‐HPLC. 相似文献
86.
Anderson S. Ribeiro Aloísia L. Moretto Marco A. Z. Arruda Solange Cadore 《Mikrochimica acta》2003,141(3-4):149-155
A simple method for the solubilization of powdered milk and soluble coffee using tetramethylammonium hydroxide (TMAH) is
proposed. While 500 μL of the reagent was used for the solubilization of 350 mg of coffee samples, milk samples required 1000 μL
of TMAH. Solubilization at 80 °C takes place within 10, 20 and 30 min for soluble coffee, whole and skim powdered milk, respectively.
Subsequently, the volume was topped up to 25 mL with deionized water. Thereafter, the concentrations of Ca, Cu, Fe, K, Mg,
Mn, Na, P, Se, Sn and Zn were determined by inductively coupled plasma optical emission spectrometry (ICP OES). When applied
to standard reference material and to commercial samples the proposed method showed good results, and it was also compared
with two other preparation methods. Limits of detection calculated for Ca, Cu, Fe, K, Mg, Mn, Na, P, Se, Sn and Zn were 2.1,
0.065, 0.11, 103, 0.088, 0.011, 1.5, 2.1, 1.1, 0.66 and 0.11 μg g−1, respectively. The RSD values were less than 10% for the certified reference materials (IAEA A-11 and BCR 63R). Statistical
tests showed that the results for the metal concentrations do not vary significantly with the different methods or with the
certified reference values, considering a confidence limit of 95%.
Correspondence: Departamento de Química Analítica, Instituto de Química, UNICAMP, 13083-862, Campinas, Brazil. e-mail: codore@igm.unicamp.br
Received August 5, 2002; accepted October 30, 2002 相似文献
87.
浆态床反应器中甲醇合成反应的数学模拟 总被引:1,自引:1,他引:0
为了对低温液相甲醇合成反应的模试及进一步的工业应用提供一定的预测和参考,用搅拌釜中得出的低温液相甲醇合成反应的动力学方程,经过合理的反应器模型假设,对低温甲醇合成鼓泡浆态床反应器进行了数学模拟,其中的非线性常微分方程组,采用变步长四阶Runge-Kutta法进行数值计算,结果表明,模试操作条件下对CO转化率和H2转化率的模拟计算结果与实际的模模试值的误差分别为13%和4%,模拟结果与模试实验结果比较相符;对不同条件下的反应速率和转化率进行了模拟预测。 相似文献
88.
Andrey S. Yasinskiy Petr V. Polyakov Yan V. Voyshel Tatiana R. Gilmanshina Sai Krishna Padamata 《Journal of Dispersion Science and Technology》2018,39(10):1492-1501
The paper describes the sedimentation behavior of concentrated high-temperature oxide-fluoride slurries with alumina particles volume fraction range 0.24?≤?φ?≤?0.32 at ~700 °C. The behavior is of interest due to perspectives of the non-Newtonian fluids usage in the future aluminium reduction technology. To characterize sedimentation behavior several techniques were used: density analysis, X-Ray diffraction, microphotography and electron scanning microscopy. Sample with ?63?µm dispersed phase as well as smelter-grade alumina which contains particles in a range of 10–150?µm has been examined. It has been found that particle settling occurs with the initial velocity 0.97·10?5 m·s?1 at φ?=?0.24 and gradually reduces reaching zero at φ close to 0.32 which was considered as a maximum packing fraction. MS?1 sedimentation mode has been identified, the type of sedimentation was found to be changed from type 1 to type 3 in the sample with φ?=?0.24. The alumina partial density distribution in suspension as a function of time was determined. Alumina average motion velocity during sedimentation was calculated to be 154·10?3?kg·m?2·s?1 at φ?=?0.24 in the top layer of the sample within the first 150?s of sedimentation. It had been reducing drastically before it reached zero after 300?s. An alumina flow was higher in the top layers. Some of the rheological properties (such as relaxation time, which increased from 7.2·10?3 to 17.7·10?3?s after the increase of φ from 0.24 to 0.28) has been determined. 相似文献
89.
Y. K. Leong Prof. David V. Boger G. B. Christie D. E. Mainwaring 《Rheologica Acta》1993,32(3):277-285
The paper describes how the theology of low concentration brown coal suspensions can be exploited to produce high concentration, low viscosity suspensions which are attractive as a potential coal-water fuel. Brown coal suspensions with solid concentrations approaching those of bituminous black coal have been prepared. The high inherent water content ( 60 wt %) and macroporosity of the brown coal have been reduced by thermal and chemical means. The hydrophobicity of the coal surface has been increased sufficiently to reduce the tendency for swelling and water uptake. This, together with densification, has allowed the solids content to be progressively improved from 30 wt % solids with raw coal to 65 wt% solids with modified coals while maintaining the viscosity of the suspension at a low level. The high solid concentration was achieved without additives. 相似文献
90.
Hiroshi Suzuki Tetsu Itotagawa Yuli Setyo Indartono Hiromoto Usui Norihide Wada 《Rheologica Acta》2006,46(2):287-295
Rheological characteristics of trimethylolethane (TME) clathrate–hydrate slurry treated with drag-reducing surfactants were investigated. Friction coefficients and apparent viscosities were measured when the concentration of TME and its hydrate fraction treated with and without drag-reducing surfactants were changed in several steps. From the results, it is found that the surfactant addition causes effective drag reduction in a pipe flow when the hydrate fraction becomes high, while effective drag reduction disappears in the cases of low hydrate fraction. The results of viscosity measurements indicate that the TME molecules disturb the formation of shear-induced structures (SIS) causing drag reduction phenomena. To investigate this interaction between TME and surfactant micelles, the effect of TME concentration on viscosity and relaxation time of solutions was discussed. From this, it was found out that there exists a critical concentration of TME on the formation of SIS and that it becomes larger as shear rate increases. Thus, we conclude that this interaction between TME and micellar structures causes less drag reduction for the cases of low hydrate fraction, while the drag reduction appears in cases of high hydrate fraction because TME concentration in liquid phase becomes small. 相似文献