کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9635848 | 1427492 | 2005 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Automated high-pressure plant for a continuous flow through a fixed bed - investigation of hydrodynamic behaviour
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
A continuously operated and computer controlled plant for high-pressure reactions and separations, utilising pressures up to 350Â MPa, was designed and constructed. The technical characterisation of the plant is based on the flow-through behaviour. Thus, breakthrough curves were recorded at pressures of 0.8, 20, and 300Â MPa, imposing a step input signal with methylene blue as tracer substance in aqueous solution. Hydrodynamic plant parameters as mean times, variances, the number of theoretical plates, Bodenstein number, and axial dispersion coefficient were determined, utilising the tanks-in-series and the dispersion model. At first, all experiments were carried out without a fixed bed in order to get the system's flow parameters. After that, a typical fixed bed consisting of modified silica gel that adsorbed almost no dye was used. These investigations were carried out to separate pore diffusion, mass transfer, and adsorption influences from disturbance caused by the fixed bed. At last, a highly adsorbing silica gel was applied to simulate a complete adsorption process. The results show that there is nearly no pressure dependency of the system's flow parameters and the disturbance, respectively. Adsorption onto silica gel, which is strongly influenced by pore diffusion and mass transfer, shows a significant pressure dependence. Mass transfer coefficients decrease with increasing pressure and so limit any desired surface reaction. Furthermore, for the amount of dispersion at hand, the number of theoretical plates N always exceeds Bo/2; consequently some standard equations for the determination of dispersion are not applicable.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: The Journal of Supercritical Fluids - Volume 33, Issue 3, March 2005, Pages 283-291
Journal: The Journal of Supercritical Fluids - Volume 33, Issue 3, March 2005, Pages 283-291
نویسندگان
Jan Jansen, Bernd Niemeyer,