In order to investigate the full mass transfer potential of the CDC reactor as a three phase chemical reactor, model reactants were hydrogenated in the CDC operating as a packed bed and slurry reactor. Two model reactants, itaconic acid and 3-nitrobenzoic acid were chosen for study and hydrogenated using a 5% PdlC catalyst for all slurry reactions and a commercially prepared 3 w/w% PdlA1203 catalyst for all packed bed reactions. To further enhance the mass transfer capabilities of the CDC, swirlflow was fitted to the lower region of the column for both packed bed and slurry reactors. For all model hydrogenation reactions, the transport parameters were evaluated and compared for the different reactor configurations enabling evaluation of the mass transfer capabilities of the CDC reactors. Two very different reactions of commercial significance were studied in the CDC firstly, the consecutive hydrogenation of 2-butyne-l ,4-diol a possible reaction stage in the production of vitamin B 12 and the hydrogenation of soyabean oil, an essential step necessary for the production of margarine. For butynediol hydrogenation, substrate inhibition occurred, preventing the full capabilities of the CDC to be utilised. For comparison with reaction in the CDC, butynediol was hydrogenated in a small stirred reactor and comparable rates of reaction were observed. Soyabean oil was hydrogenated in both packed bed and slurry modes and showed comparable rates of reaction between the two different reaction modes. From the evaluated transport parameters and reaction kinetics, the CDC operated in both packed bed and slurry modes achieved reaction which was occurring under diffusion resistance free conditions, whereas normally soyabean oil is hydrogenated in conditions which are limited by resistances to diffusion. For both reaction modes, high linolenic selectivities were achieved. This study has shown that the CDC is suitable for use as a three phase chemical reactor providing a high degree of chemical reaction which is not limited by resistances to mass transfer. The CDC is particularly suitable for reactions were efficient mass transfer is required with chemical reaction.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:588602 |
| Date | January 1995 |
| Creators | Khan, Zaffer |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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