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Brask J Damstrup ML Nielsen PM Holm HC Maes J De Greyt W 《Applied biochemistry and biotechnology》2011,163(7):918-927
An integrated biodiesel process that combines enzymatic esterification and alkaline transesterification is suggested. With
focus on the enzymatic step, the paper provides proof of concept and suggestions for further process development. Hence, palm
fatty acid distillate (PFAD) has been enzymatically converted to fatty acid methyl esters in a two-step process using the
immobilized lipase Novozym 435 in packed-bed columns. With only a small excess of methanol, the first reaction stage could
reduce the free fatty acid (FFA) content from 85% to 5%. After removal of water by simple phase separation, it was possible
to lower the FFA content to 2.5% in a second reaction stage. Both reaction stages are relatively fast with suggested reaction
times of 15 min in column 1 (productivity 10 kg/kg/h) and 30 min in column 2 (productivity 5 kg/kg/h), resulting in 15% FFA
after column 1 and 5% FFA after column 2. A lifetime study indicated that approximately 3,500 kg PFAD/kg Novozym 435 can be
treated in the first reaction stage before the enzyme has become fully inactivated. With further optimization, the enzymatic
process could be a real alternative to today’s sulfuric acid catalyzed process. 相似文献