Tubular reactors illumination

Figure 16 Tubular reactor illuminated by beam solar radiation.

Figure 19 Distribution of spectral volumetric absorbed power inside a tubular reactor illuminated by a 90° rim angle parabolic trough solar concentrator. Wavelength 325 nm and catalyst concentration 0.15 gL (Reprinted from Arancibia-Bulnes and Cuevas, 2004, with permission from Elsevier).

Extending the equipment, the authors (Beale et al., 2005) recently added energy dispersive X-ray absorption spectroscopy (XAS). Raman and UV-vis spectra are recorded by illuminating opposite sides of a catalyst bed in a vertical tubular reactor and detecting the scattered and reflected light as described above. XAS is performed in the same horizontal plane but in transmission and with the beam orthogonal to the incident radiation of the other two methods. Example spectra were recorded for samples at 823 K. A combination of UV-vis (fiber optics) and XAFS spectroscopy for investigation of solids has also been described by Jentoft et al. (2004), who reported UV-vis measurements of samples at 773 K. 

As discussed previously, several solar photoreactor geometries can be reduced to cylindrical glass tubes externally illuminated by different types of reflectors, like parabolic troughs, CPC, V-grooves, or without reflector, directly illuminated by the sun. In this section the general solution of the PI approximation for this t)q5e of photo reactors is reported. This general solution is applicable to any particular reactor if the flux distribution impinging on the wall of the tubular reaction space is known. 

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