Trickle tower reactor

Bipolar Trickle Tower Reactor British Technology Group Series (<60) of bipolar elements in a column Discontinuous via leaching or removal of the carbon bed No / /... 

Trickle tower reactors containing a number (typically <60) of vertically stacked, bipolar electrode layers have been studied for metal-ion removal at the University of Southampton [41-44]. Earlier studies [41-43] employed layers of hollow carbon cylinders known as Raschig rings (see figure 10a). The relatively low active cathode area per unit reactor volume together with constructional difficulties associated with these packings led to the examination of alternative materials such as felt, particles, foam and perforated plates [44]. 

Fleischmann, M. and Ibrisagic, Z. (1980) Electrochemical measurements in bipolar trickle tower reactors. Journal of Applied Electrochemistry, 10, 151. 

It is also possible to operate three-dimensional electrodes in a bipolar manner, as in the case of the bipolar trickle tower reactor (Fig. 2.26) where each electrode layer is separated from its neighbour by an insulating mesh. The potential distribution along the height of each layer is non-uniform (Fig. 2.26(b)) and the packing conditions, electrolyte composition and electrolyte flow must be controlled to minimize the bypass current flowing past each layer, within the reactor envelope. Hence, such reactors are best suited to poorly conducting electrolytes. 

Fig, 2-26 The bipolar trickle-tower reactor, (a) A schematic, (b) The potential distribution over a single bipolar layer The electrode is assumed to have a constant potential, while the solution potential, varies with distance down the layer. The driving force for reaction varies with position, being largest near the ends of each electrode... 

The bipolar trickle tower reactor has already been mentioned (Fig. 2 26). Here, the electrolyte falls, under gravity, down a packed column containing a bipolar array of electrodes. In order to maintain trickle flow (and hence, minimize bypass currents) the flow rate is restricted High flow rates cause flooding while tow values result in incomplete wetting of the electrodes. 

Electrolyte flow may trickle through the porous electrode (as in the trickle-tower reactor (Fig. 2.26(a)) or be pumped upwards through a flooded-bed electrode eg. Fig, 2.35(b)). 

A semi-regular array of elements, as in the bipolar trickle-tower reactor (Fig. 2.26). 

The overhead of the depropanizer is sent to the propylene fractionator. The methylacetylene (MA) and propadiene (PD) are usually hydrogenated before entering the tower. An MAPD converter is similar to an acetylene converter, but operates at a lower temperature and in the Hquid phase. Due to recent advances in catalysis, the hydrogenation is performed at low temperatures (50—90°C) in trickle bed reactors (69). Ordy rarely are methylacetylene and propadiene recovered. 

The calcium bisulfite acid used in the manufacture of sulfite cellulose is the product of reaction between gaseous sulfur dioxide, liquid water, and limestone. The reaction is normally carried out in trickle-bed reactors by the so-called Jenssen tower operation (E3). The use of gas-liquid fluidized beds has been suggested for this purpose (V7). The process is an example of a noncatalytic process involving three phases. 

The scale-up and design configurations of fluid-bed chemical reactors have evolved rapidly and empirically. An example is fluid catalytic cracking (FCC) [13]. The general fluid-bed concepts developed early. However, the correlations describing the various rate processes and other operational phenomena developed slowly because they could not easily be related back to already established data bases developed for other systems in the case of trickle-bed reactors, data developed for packed-bed absorption towers were utilized. 

RHDS experiments were carried out in a trickle bed reactor. The atmospheric tower bottom (ATB) of Kuwait crude oil was passed the reactor (0.5 mL/nin) at 663 K, 7582 kPa, and WHSV= 1,5, The hydrogen flow rate was 300 mL/min at STP. The details of the experiment have been reported in ref, 5,... 

The Simulation or Design of a Packed Bed Absorption Tower The Absorption of GO2 into a Monoethanolamine (MEA) Solution 14.3.2 Two-Phase Fixed Bed Gatalytic Reactors with Gocurrent Downflow. Trickle Bed Reactors and Packed Downflow Bubble Reactors... 

Attached growth processes Wastewater treatment processes in which the microorganisms and bacteria treating the wastes are attached to the media in the reactor. The wastes being treated flow over the media. Trickling filters, bio-towers, and RBCs are attached growth reactors. These reactors can be used for removal of BOD, nitrification, and denitrification. 

Leading characteristics of five main kinds of reactors are described following. Stirred tanks, fixed beds, slurries, and three-phase fluidized beds are used. Catalyst particle sizes are a compromise between pressure drop, ease of separation from the fluids, and ease of fluidization. For particles above about 0.04 mm dia, diffusion of liquid into the pores and, consequently, accessibility of the internal surface of the catalyst have a minor effect on the overall conversion rate, so that catalysts with small specific surfaces, of the order of 1 m2/g, are adequate with liquid systems. Except in trickle beds the gas phase is the discontinuous one. Except in some operations of bubble towers, the catalyst remains in the vessel, although minor amounts of catalyst entrainment may occur. 

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