The subject of this research was the investigation into hydrodynamics of a trickle-bed reactor operating at the periodic liquid feed. The liquid-induced pulsing flow (LIPF) was obtained by means of the base-impulse method (the changes in the liquid flow rate between low, but not equal zero, and high value of this parameter). The main hydrodynamic parameters (boundaries of the hydrodynamic regime changes, gas pressure drop, liquid hold-up) as well as the effect of physicochemical properties of the liquid phase on the measured parameters values were determined.
The holdup and axial dispersion of aqueous phase has been measured in trickle bed reactors as a function of liquid and gas flow rates using radioisotope tracer technique. Experiments were carried out in a glass column of inner diameter 15.2´10-2 m column for air-water system using three different types of packings i.e. non-porous glass beads, porous catalysts of tablet and extrudate shape. The range of liquid and gas flow rates used were 8.3´10-5-3.3´10-4 m3/s and 0-6.67´10-4 m3/s, respectively. Residence time distributions of liquid phase were measured and mean residence times were determined. The values of liquid holdup were calculated from the measured mean residence times. It was observed that liquid holdup increased with increase in liquid flow rates and was independent of increase in gas flow rates used in the study. Two-parameter axial dispersion model was used to simulate measured residence time distribution data and values of mean residence time and Peclet number were obtained. It was observed that values of Peclet number increases with increase in liquid flow rate for glass beads and tablets and remains almost constant for extrudates. The values of mean residence time obtained from model simulation were found to be in good agreement with the values measured experimentally.
The subject of this research was the investigation into hydrodynamics of a trickle-bed reactor operating in natural pulsing flow and at the periodic liquid feed. The measurements were performed by means of the base-impulse method for fast changes of the liquid velocity (fast mode). The effect of the reactor operation and liquid physicochemical properties on a position of the transition line between hydrodynamic regimes and values of basic hy-drodynamic parameters was analyzed.
Zjawiska fizyczne występujące podczas przepływów w reaktorach trójfazowych są złożone i trudne do analizy. Mimo że badania w tym zakresie są prowadzone od wielu lat, to dotychczas nie udało się rozwiązać wszystkich problemów pojawiających się podczas tego rodzaju procesów. Dotąd, do badania reaktorów trójfazowych wykorzystywane były czujniki lokalne, a także metody kolorymetryczne i tomograficzne. Techniki tomograficzne promieni Rentgena, promieniowania gamma czy rezonans magnetyczny są jednak bardzo kosztowne i oferują niską rozdzielczość czasową. Z kolei elektryczna tomografia impedancyjna i rezystancyjna wymagają fizycznego kontaktu z badanym medium i nie nadają się do badania substancji nieprzewodzących. Na tym tle tomografia pojemnościowa wydaje się bardzo atrakcyjną metodą. W niniejszym artykule zostały przedstawione wyniki doświadczeń przeprowadzonych z zastosowaniem elektrycznej tomografii pojemnościowej i czujnika pomiarowego z wewnętrznymi elektrodami, do badania przepływów cieczy przez złoże w postaci ciała stałego, w doświadczalnym modelu reaktora trójfazowego.
EN
Trickle bed reactors are widely used for a number of different applications in industry. Investigations are very difficult to perform due to the opaque nature of such systems. The researches on trickle bed reactors hydrodynamics are conducted for a long time. Since now some attempt to use local probes, colorimetric and tomographic techniques were performed. However, MRJ, X-ray and gamma ray transmission tomography suffer from low temporal resolution and are cost-intensive. On the other hand, Electrical Impedance or Resistance Tomography need to be in contact with investigated substance and cannot be used for non-conducting materials. At this background Electrical Capacitance Tomography seems to be very attractive technique. In this paper, the results of performed investigations on trickle bed reactor experimental setup, with a use of Electrical Capacitance Tomography combined with a sensors comprised of internal electrodes, are presented.
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