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PRODUCTION OF ETHANOL FROM BIOMASS : SEPARATION PROCESS

Objective

THE AIM OF THE RESEARCH IS TO DEVELOP MEMBRANE SEPARATION PROCESSES FOR ETHANOL-WATER MIXTURES IN BOTH HIGH CONCENTRATION RANGE (ETHANOL DEHYDRATION) AND LOW CONCENTRATION RANGE (ETHANOL REMOVAL FROM FERMENTATION BROTH).

MICROPOROUS HYDROPHOBIC MEMBRANES HAVE BEEN INVESTIGATED FOR SEPARATION AT LOW ETHANOL CONTENT. ESSENTIALLY THE ROLE PLAYED BY THE MEMBRANE IS TO IMMOBILIZE A GAS-LIQUID INTERFACE AT THE PORE ENTRANCE. BOTH AIR GAP MEMBRANE DISTILLATION (AGMD) AND PERVAPORATION WITH HYDROPHOBIC MEMBRANES ARE UNDER INVESTIGATION. THE EXPERIMENTAL APPARATUS EMPLOYED IS THE SAME IN BOTH TYPES OF EXPERIMENTS, THE MAIN DIFFERENCE IS THE PRESSURE OF THE GAS PHASE WHICH IS GRATHER IN AGMD AND LOWER IN PERVAPORATION (WITH RESPECT TO THE EQUILIBRIUM VAPOR PRESSURE OF THE LIQUID PHASE). IN AGMD A TEMPERATURE DIFFERENCE IS MAINTAINED BETWEEN THE LIQUID PHASE (TB1) AND THE WALL CONFINING THE AIR GAP (TB2). AS A CONSEQUENCE WATER AND ETHANOL VAPORS DIFFUSE THROUGH A STAGNANT FILM OF AIR CONDENSATION TAKES PLACE OVER THE COLD BOTTOM OF THE SEMICELL.
IN PERVAPORATION, ON THE CONTRARY, CONVECTIVE TRANSPORT IS THE BASIC PHYSICAL MECHANISM AND CONDENSATION TAKES PLACE IN A COLD TRAP SEPARATED FROM THE CELL. THE CRUCIAL PREREQUISIT FOR BOTH PROCESSES IS THE NONWETTABILITY OF THE MEMBRANE. THE LIQUID REPULSING PROPERTIES OF PTFE AND POLYPROPILENE POROUS MEMBRANES HAVE BEEN TESTED MEASURING THE PENETRATION PRESSURE AS A FUNCTION OF THE ETHANOL CONCENTRATION IN THE LIQUID PHASE. THE FLUX AND SELECTIVITY HAS BEEN INVESTIGATED IN A WIDE RANGE OF TEMPERATURES AND COMPOSITIONS; MATHEMATICAL MODELS HAVE BEEN DEVELOPPED AND COMPARED WITH EXPERIMENTAL RESULTS.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Separem SpA
Address
Via Per Oropa 118
13051 Biella
Italy

Participants (1)

Università degli Studi di Bologna
Italy
Address
Viale Del Risorgimento 2
40136 Bologna