Comparative analyses of three olive mill solid residues from different countries and processes for energy recovery by gasification

Abstract

Biomass is a renewable energy source which may provide a significant contribution to the reduction of fossil fuels consumption and the associated environmental impacts. The use of agricultural or agro-industrial waste such as solid residues from olive oil production is particularly relevant since it may combine several benefits. Gasification is a promising waste-to-energy technique for this type of lignocellulosic residues. The technology however is adapted to a relatively limited panel of solid waste fuels of defined specifications, which must therefore be characterized properly to assess their adaptation. The purpose of this research was to analyze and compare three different olive mill solid residues by complementary techniques such as Fourier transform infrared spectroscopy (FTIR) and thermochemical methods, in order to characterize these residues as potential fuels for gasification. The results obtained underlined the complex nature of the residues and indicated that they were mainly organic, with very little mineral matter. In addition to the major organic components (cellulose, hemicelluloses and lignin), the presence of several minor organic constituents was shown by thermogravimetry coupled to differential scanning calorimetry and FTIR. The gas produced from pyrolysis was analyzed by gas chromatography and mass spectrometry. It was found to contain several degradation products from lignocellulosic material and olive oil, such as hydroxyacetone, furfural and methoxyphenols. The influence of the olive oil extraction process (two-phase or threephase) was also demonstrated. It was shown that the thermochemical degradation of olive mill residues followed a complex pathway but the composition of the residues met the requirements for gasification for most parameters.

Is anaerobic digestion a feasible alternative to the combustion of olive mill solid waste in terms of energy production? A critical review

“…Relation between the pre-treatment energy consumption (kJeq/kgOMSW) for all reviewed studies using pretreated OMSW against the variation in methane production (%), and net energy production (%) compared to the untreated OMSW. 1 A scale up factor of 0.90 was applied to adjust the methane yield from batch experiments to a continuous operation mode, according to the results from previous section 2 In terms of Net Energy Production 3 Negative values were used for reduction in Net Energy Production respect to OMSW combustion 4 Despite the methane yield was not increased, this pretreatment was included due to the achieved reduction of the hydraulic retention time, reducing the energy demand of…”

“…Although the three-phases system obtains a higher olive oil recovery, implies high water consumption and, hence, the generation of vast volumes of wastewater to be treated. 3 In Spain, the highest producer worldwide (30% globally) around 97% of the olive oil is obtained through the two-phase system, as well as in other countries with water shortages such as Italy, Greece or Chile. 4,5 As by-product, the two-phase system generates four tons of olive mill solid waste (OMSW) per produced ton of olive oil.…”

Caractérisation de grignons d’olives en vue d’une valorisation thermochimique par gazéification

“…Les courbes TG obtenues sous azote (non montrées dans ce papier), assimilées aux profils de pyrolyse, montrent également deux contributions principales de perte de masse dans la région 200-600°C avec des réactions endothermiques associées en ACD de faible intensité (Ducom et al, 2020).…”

Synthesis and Characterization of Greener Ceramic Materials With Lower Thermal Conductivity Using Olive Mill Solid Byproduct

“…Innovative technologies that incorporate different forms of biomass and other alternative solid products (produced from various waste treatments) into red ceramics seem to develop rapidly at a global level. Actually, biomass energy potential is addressed to be the most promising among the renewable energy sources, due to its spread and availability worldwide [1][2][3]. The interesting points in these technologies are that they: a) can act as an efficient disposal method; b) exploit the biomass energy content into clay bodies for fuel savings; c) use of materials with organic matter as pore-forming agents [4,5].…”