Experimental identification of design parameters for novel reactor-separator

• Published in: AIChE journal 2005-04, Vol.51 (4), p.1207-1213
• Main Authors: Shah, Parag S., Suppes, Galen J.
• Format: Article
• Language: English
• Subjects: alcoholysis; Applied sciences; biodiesel; Biodiesel fuels; Chemical engineering; Exact sciences and technology; fats; Gas separation; Methanol; oils; reactor; Reactors; separator; thermal diffusion
• ISSN: 0001-1541; 1547-5905
• DOI: 10.1002/aic.10386

The separation of methanol from glycerin and biodiesel in biodiesel manufacturing significantly adds to the cost of the biodiesel. A novel reactor–separator, based on flowing effluents through a temperature gradient, keeps the methanol in the reactor and could decrease the cost of separating methanol from glycerin and biodiesel. The reactor–separator has a lateral extension at the bottom of the reactor, which is referred as the “auto‐recycle discharge.” This discharge replaces a conventional flash separator and condenser. The ability of the auto‐recycle discharge to remove methanol from glycerin and biodiesel was experimentally evaluated at discharge temperatures ranging from 60 to 180°C and pressures from 101 to 515 kPa. Exiting compositions approached methanol's bubble point compositions under the assumption of a nonvolatile second component (either glycerin or biodiesel), and this constraint largely defined the separation that was achieved. Glycerin with less than 2% methanol was obtained using this separator. When extended for the separation of methanol from biodiesel, less than 1% methanol remained in the biodiesel effluent. © 2005 American Institute of Chemical Engineers AIChE J, 2005