| 摘要 |
An annular throughflow photoreactor for oxidative photopurification includes an elongate radiation source surrounded by a transparent wall in the form of a spacer tube at a radial spacing of more than 3 cm, preferably in the range of more than 3 cm to 13 cm. The irradiance, i.e. the radiant flux per irradiated area is thereby reduced in comparison to a classic annular photoreactor. At unchanged irradiation power, this results in considerably increased quantum yields or extent of photoconversion in cases in which such conversion is dependent upon the square root of the irradiance, and thus enables enormous savings in radiation energy. Under such conditions, the photoconversion may be additionally increased by using low absorber concentrations and infeeding further absorber on the inside of the outer wall of the photoreactor as well as by working in the presence of gaseous oxygen at an oxygen pressure up to 3 bar and, preferentially, at pH 3. The throughflow photoreactor may comprise an annular single chamber or dual chamber photoreactor or a tank reactor having an annular array of irradiation units including the spacer tubes. A plural number of such photoreactors may be series connected.
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