Vertical concentric reactor system

Bubble fractionation is similar to foam fractionation except that there is no foam produced in the system thus, it is applied to dilute surface-active solutions that do not foam while foam fractionation is applied to surface-active solutes at high concentration (76,77). Technically speaking, bubble fractionation represents an operation in which gas is bubbled up through a vertical bubble reactor containing the surface-active solute(s)... 

A mixture of ethylene, high purity oxygen, and recycle gas is reacted in a vertical multitubular reactor filled with silver oxide catalyst. The exothermic heat of reaction is removed by the generation of steam in the reactor shell. The ethylene oxide product is absorbed from the reactor effluent gas with water. It is then recovered from the water stream by steam stripping, partial condensation, and adsorption to form a concentrated aqueous solution. The aqueous solution is further concentrated in a two-stage distillation system. The first-stage separates water and the second removes light ends. 

Fig. 2. Bifurcation diagrams describing the behavior of the CO/O2 system as CO pressure is varied, (a) CO2 effluent concentration (which is proportional to the reaction rate) as a function of CO inlet concentration at four different temperatures in an atmospheric reactor over a pulverized Pt/silica/alumina catalyst. Oscillation existence regions are indicated by vertical hatching (from Ref. 98). (b) Work function maxima and minima plotted as a function of CO pressure at 540 K on Pt(l 10). The periodicity of the oscillations (as indicated above the curve) is seen to increase as CO pressure is decreased. (From Ref. 231.)...

Some researchers use plug-flow reactors (PFRs), also known as packed bed reactors or column reactors (if run vertically) to model natural systems. In an ideal plug-flow or column reactor, fluid is pumped or drained through a packed bed of mineral grains and every fluid packet is assumed to have the same residence or contact time (Hill, 1977). The residence time equals the ratio of the pore volume of the reactor (Vo) divided by flow rate Q. With no volume change in the reaction, radial flow, or pooling of fluid in the reactor (Laidler, 1987), the outlet concentration varies from the inlet concentration according to ... 

The catalytic activity of the prepared catalysts for methane combustion was tested in a flow reactor unit. Bottled methane (99.995 % purity from AGA, Sweden) and air were fed to the system using mass flow controllers, giving a methane concentration of 2 vol%. The space velocity in all experiments was 50,000 h". The catalysts were placed in a vertical tubular Inconel reactor situated in a tubular furnace. The exiting gases were analyzed by gas chromatography using a Packard model 427 GC, equiped with a Poraplot Q fused silica capillary column and a thermal conductivity detector. The temperature in the furnace was controlled to give a linear temperature ramp of 2 °C/min in all experiments. Hence, the conversion of methane to carbon dioxide and water was determined as a function of the gas inlet temperature. 

Of course the spectrum of quantities, which need to be measured in a fluidized bed, is much wider. These include, for example, local solids volume concentrations, solids velocities and solids mass flows, the vertical and the horizontal distribution of solids inside the system or the lateral distribution of the fluidizing gas. In response to these needs a number of more sophisticated measurement techniques were proposed. For example, suction probes were developed to measure local solids and mass flow, heat transfer probes were proposed for detection of de-fluidized zones and solids flow inside fluidized-bed reactors. Other techniques include capacitance probes, optical probes, or y-ray densitometry - a detailed review was given recently by Werther [1]. Cody et al. 2 reported the use of an acoustic probe to measure particle velocity at the wall of fluidized beds. 

---