Photochemical reactor tubular

B. 2-Phenylthio-5-heptanol. A photochemical reactor consisting of a tubular pyrex flask, a magnetic stirbar, a water-cooled high pressure mercury lamp, and an argon inlet tube (Note 9) is charged with... 

Figure 2. Diagram of a tubular photochemical reactor irradiated by a laser beam [2, 3, 7] (dimensions in mm). 

Figure 7. Falling film tubular photochemical reactor, for reactions requiring excitation of a reactive gas [2,3].

Figure 11. Relative irradiance along the diameter of a cylindrical photochemical reactor surrounded with many tubular light sources transmittance (T) of the reaction mixture through 1 cm (1) T = 0.7 (2) T = 0.65 [2, 3, 52],...

In the RI model, all incident rays intersect at the center axis of the reactor tube, and Eq. 68 produces an infinite value of irradiance as r - 0. The DI model, on the other hand, proposes parallel layers of rays which are wider than the diameter of the tubular reactor and which traverse the reactor perpendicularly to its axis from all directions with equal probability. The calculated results of both models are far from reality, as found in industrial size photochemical reactors. Matsuura and Smith [107] proposed an intermediate model (PDI model, partially diffuse model, Figure 25b) in which parallel layers of rays are assumed, and the width of each is smaller than the diameter of the tubular reactor. These two-dimensional bands form by themselves radial arrangements, the center ray of each band intersecting the... 

Within the general concept of the ESVE models, Alfano et al. conceived a model for the radiant power profile of a tubular light source located in the focal axis of a parabolic reflector in order to analyze the design of a cylindrical photochemical reactor irradiated from the bottom [118]. Differences between experimental and calculated (ESVE) results were always less than 15%. 

Figure 26.1 Examples of basic photochemical reactors (some adapted from Cassano et al., 1995). (a) tubular photoreactor inside a cylindrical reflector of elliptical cross section (b) annular photoreactor (c) film-type photoreactor (d) single-lamp multitube continuous photoreactor (e) perfectly-mixed semibatch cylindrical photoreactor irradiated from the bottom by a tubular source and a parabolic reflector...

Methane, chlorine, and recycled chloromethanes are fed to a tubular reactor at a reactor temperature of 490—530°C to yield all four chlorinated methane derivatives (14). Similarly, chlorination of ethane produces ethyl chloride and higher chlorinated ethanes. The process is employed commercially to produce l,l,l-trichloroethane. l,l,l-Trichloroethane is also produced via chlorination of 1,1-dichloroethane with l,l,2-trichloroethane as a coproduct (15). Hexachlorocyclopentadiene is formed by a complex series of chlorination, cyclization, and dechlorination reactions. First, substitutive chlorination of pentanes is carried out by either photochemical or thermal methods to give a product with 6—7 atoms of chlorine per mole of pentane. The polychloropentane product mixed with excess chlorine is then passed through a porous bed of Fuller s earth or silica at 350—500°C to give hexachlorocyclopentadiene. Cyclopentadiene is another possible feedstock for the production of hexachlorocyclopentadiene. 

The classical procedures used by the chemist or engineer to obtain polymerization rate data have usually involved dilatometry, sealed ampoules, or samples withdrawn from model reactors—batch, tubular, and CSTR s alone or in various combinations. These rate data, together with data on molecular weight can be used to obtain the chain initiation constant and certain ratios such as kp2/kt and ktr/kp. Some basic relationships are shown in Figure 5. To determine individual rate constants such as kp and kt, other techniques are needed. For example, by periodic photochemical initiation it is possible to obtain kp/kt. If the ratio kp2/kt (discussed above) is also known, kp and kt can each be calculated. Typical techniques are described by Flory (20). 

Photochemical tubular flow and stirred tank reactor O3-UV HjOj-UV Reaction simulation, reactor comparison Shimoda et al. (1997)... 

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