Resumo (PT):
Abstract (EN):
This work aims to explore the production of
biodiesel from oil extracted from spent coffee grounds
(SCG) via enzymatic catalysis with the Lipozymes RM IM,
TL 100L and CALB L, in the presence of a co-solvent, and
to optimize the reaction conditions. A three factors design
of experiments was performed to evaluate the influence
on the reaction performance of ethanol/oil molar ratio,
enzyme concentration and reaction temperature. Oil was
extracted from air dried SCG with hexane in a pilot solid/
liquid extractor, resulting in 6.4% (m/m oil) in dry SCG.
The coffee oil was characterized for its kinematic viscosity (38.04 mm2
/s), density (0.903 g/cm3
), heating value
(38 MJ/kg), iodine value (63 g I2/100 g oil), water content
(0.1458%), acid value (44.78 mg KOH/g oil), flash point
(>120°C) and triglyceride content (82.8%). Based on the
design of experiments, the best conditions for the transesterification reaction are 5:1 molar ratio of ethanol/oil, 4.5%
(m/m oil) of enzyme and 45 °C of temperature, resulting in
an experimental yield of 96.7%, with 87.6% (m/m) of esters
content. Additionally, it was studied the effect of water in
the transesterification reaction, using ethanol at 92, 85 and
75% (v/v). Results show that the best reaction yield (97.2%)
and esters content (92.1%) were obtained using ethanol
92%. Although the esters content of the biodiesel obtained
from coffee oil does not accomplish the EN 14214:2009
requirements, it is promising as there is the possibility to blend the coffee oil with oil from other sources in order to
meet the standard requirements.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
14