Production and Characterization of the Bio-Oil Obtained by the Fast Pyrolysis of Spent Coffee Grounds of the Soluble Coffee Industry

Abstract

Agro-industrial wastes are abundant and low-cost sources of energy and chemicals. Biomass account for 14% of the world's energy production. Industrial residues of production of soluble coffee (spent coffee grounds -SCG) have great potential due to its large-scale production and can be transformed by pyrolysis, in liquid, solid and gaseous products with applications from energy to chemicals. This work has the objective of producing bio-oil from the pyrolysis of industrial SCG, characterize it by chromatography and indicate its possible applications. As SGC contains a large amount of glycerides, they were extracted from SGC before the pyrolysis, aiming to obtain a better bio-oil from the residue. The yield in vegetable oil was 5.2% and its analyses showed that 50% are saturated acids (mainly palmitic 27.6%) and other 50% are unsaturated ones (mainly linoleic acid 35.3%). This composition qualifies this oil for biodiesel purposes. The residue (SGC after extraction) was submitted to pyrolysis, yielding 30% in liquid products, being 6% bio-oil. The bio-oil was analyzed by gas chromatography being identified free fatty acids, hydrocarbons, phenols and N-compounds. The heteroatomic compounds limit the use as biofuel but can be interesting for the pharmaceutical, agrochemical and fine chemicals industries.

Ecotoxicological Effects of Biochar Obtained from Spent Coffee Grounds

“…In this study, the yield to produce biochar from SCG was 20%. This result agrees with the literature, as the expected yield is between 20 and 25% 31 . However, it is worth noting that higher yields can be obtained.…”

Molecular, Chemical, and Sensory Attributes Fingerprinting of Self-Induced Anaerobic Fermented Coffees from Different Altitudes and Processing Methods

“…The intensity of this region increases after roasting the samples of N and PN, mainly at 1400. Another region to be considered is 3500–3200 cm −1 which corresponds to the stretching vibrations of O-H or N-H functional groups, carboxylic acids, amines, amides, and alcohols [ 26 ]. In the N process, the intensity of this region was different for each altitude.…”

Thermal Contaminants in Coffee Induced by Roasting: A Review

“…In drying, the extract can be subjected to two processes: spraying (sprinkler) or freezing (freeze drying). This type of coffee has a longer shelf life when compared with traditional coffee, but lower caffeine concentration (about 20% less) [ 72 , 73 , 74 , 75 ].…”