Читать книгу Biodiesel Technology and Applications - Группа авторов - Страница 23

In order to maximize production and benefit of product we need to perform optimized laboratory experimental procedure at a large industrial scale, so, bioreactors are used in this regard. But results should be equivalent to laboratory procedure [45]. There are some complications like production should be cost effective and in good quality. Carefully planned methodologies and objectives should be designed for effectively large-scale production. This also includes bioreactor parameters like fluid flow performance and unexpected environmental variation. In case of industrial transesterification process, the main hurdle is multiphasic nature of lipase catalyzed synthesis and hydrolysis because this does not allow the bioreactor equivalent to laboratory experiment. Many types of bioreactors such as fluid beds, recirculation membrane reactors, expanding beds, static mixers, batch stirred tank reactors (STRs), and packed bed reactors (PBRs) have been used for enzymatic biodiesel production [51, 52]. One of the leading differences between STRs and PBRs is presence of enzyme at specific location in reactor, e.g., in STRs it is dispersed in the reaction mixture but in PBRS it is fixed in a column. STRs are the simplest type of bioreactors containing just reactor and propeller that stirs reaction mixture mechanically. Batch operated STR need to be empty, clean, and again add reactants for the reaction in order to start new batch process and this is main reason of batch process to produce less yield of the product. Solution of this problem is to use STRs with continuous mode. This does not require to remove enzyme and ingredients to start another cycle. There is a filter attached at the reactor outlet that preserves enzyme in the reactor [52]. PBRs can also be used in both batch and continuous mode but later is more advantageous because of its low labor cost, stable and automated controlled operating conditions, high efficiency, protects enzyme from shearing stress, continuous glycerol removal, and ease of maintenance [53–55]. Currently, most of the bioreactors are used in batch mode with STRs but a lot of research has been done on PBRs usage and its optimization for enzymatic biodiesel production to find this PBR method is better than batch mode STR [56–59].