Vertical column reactor

Figure 10.1 Vertical column reactor for the continuous bulk polymerization of styrene. (From Winding, C.C. and Hiatt, G.D., Polymeric Materials, McGraw-Hill, New York, 1961. With permission.)...

Three-phase fluidized bed reactors are used for the treatment of heavy petroleum fractions at 350 to 600°C (662 to 1,112°F) and 200 atm (2,940 psi). A biological treatment process (Dorr-Oliver Hy-Flo) employs a vertical column filled with sand on which bacderial growth takes place while waste liquid and air are charged. A large interfacial area for reaction is provided, about 33 cmVcm (84 inVirr), so that an 85 to 90 percent BOD removal in 15 min is claimed compared with 6 to 8 h in conventional units. 

Cladding for the reactor vessel is a continuous integral surface of corrosion-resistant material, having -inch (0.56 centimeter) nominal thickness, and a f-inch minimum thickness. The reactor vessel is supported by four vertical columns located under the vessel inlet nozzles. These columns are designed to flex in the direction of horizontal thermal expansion and thus allow unrestrained heat-up and cool-down. The columns also act as a hold-down device for the vessel. The supports are designed to accept normal loads and seismic and pipe rupture accident loads. 

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 ... 

Direct bubbling with a mixture of air and C02 is used in many closed photobioreactors. The mass transfer capacity (as measured by the volumetric oxygen transfer coefficient, kLa) increases with decrease in the bubble diameters (achieved by using spargers with very small diameter pores) and with increase in the aeration rate. In vertical columns (Fig. 4), the gas transfer from the gas bubbles to the medium is high since the gas bubbles remain submerged in the broth until they exit the reactor. Thus bubble column bioreactors have been used for many biological processes. 

In its most simple form a bubble column reactor basically consists of a vertical cylinder with a gas distributor at the inlet, as sketched in Fig 8.1. Simple construction and lack of any mechanically operated parts are two characteristic aspects of the reactor. In general, the bubble column is an adaptable type of reactor which is reasonable in price and can be built in large sizes. The ratio between length and diameter may vary, but ratios between 3 and 10 are most common [28]. Units of 100 — 200 (m ) are regarded as very large in the chemical industry. 

Vapour phase aniline alkylation is carried out over ca. 0.5 g catalyst at 673 K and feed rate 12 cm h" g in a vertical flow reactor. N2 is used as carrier gas. Products are collected every hour for 4h and are analysed by a gas chromatograph using a column of Apiezon-L treated with 2% KOH on chromosorb 80/100 A.W. Alkylated anilines obtained are analysed to be mainly N-ethylaniline (NEA), NN diethylaniline (NNDEA) and traces of toluidine. 

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