Fast pyrolysis as an alternative to the valorization of olive mill wastes

Abstract

BACKGROUND The valorization of organic wastes through fast pyrolysis appears to be a highly promising option for decreasing pollutants and reducing consumption of natural resources. For this purpose, three different olive pomace samples were studied to determine how olive crop location and the extraction process could influence bio‐oil product distribution. Olive pomace was selected as the feedstock due to the importance of the olive oil industry in Spain. RESULTS In this study, the conditions of fast pyrolysis were optimized using lignin as a reference, with the optimum conditions being 500 °C, 20 °C ms−1 as the heating rate and 15 s as the vapour residence time. The olive pomace results determined that not only their chemical composition, but also their fat content had a remarkable effect on product distribution obtained after fast pyrolysis. However, whereas high lignin content enhanced phenol production, cellulose decomposed to carboxylic acids. In addition, due to current global warming, the carbon dioxide (CO2) burden of the three samples was calculated using mass spectroscopy. The OPGC sample gave off the lowest amount of greenhouse gases, followed by OPMNE and OPMN. CONCLUSIONS The higher fat content in the sample enhanced carboxylic acid production. The difference in phenol production between OPMN and OPMNE could be attributed to the presence of potassium. From an environmental point of view, the use of olive pomace wastes could reduce CO2 emissions with further research and by developing experimental processes. © 2020 Society of Chemical Industry

Sustainable Valorization of Olive Pomace Waste to Renewable Biofuels, Biomaterials and Biochemicals Via Pyrolysis Process: Experimental and Numerical Investigation

“…After this temperature, the passive zone started where the devolatilization practically finished and there is no loss of additional mass. Similar results were reported by (Dorado et al 2021) when the temperature reaches 600°C, the weight loss rate was about 0 %wt./min.…”

“…The OPW proximate parameters are summarized in Table 1. OPW presents a high VM content about 73 wt.% on dry basis which shows the promoting potential of devolatilization of the biomass (Alcazar-Ruiz et al 2021) and relatively low ash content (about 2%) compared to other olive residues reported in literature (Dorado et al 2021) (Table 1). The OPW moisture content as received is about 10.44 wt.% and it reaches 3.44 % after air-drying, which is tolerable for thermochemical conversion via pyrolysis process since moisture content is one of the main parameters in biomass pyrolysis, because it inhibits the process if it surpasses 10% by weight 1, reveals the richness of OPW with K (6.46 mg/g of sample) and Ca (4.64 mg/g of sample).…”

“…The weak peaks centered on 1436 and 1379 cm -1 correspond to the asymmetric bending of C-C in the lignin structure (Lestander et al 2018). Besides, another peak around 1245 cm -1 could be attributed to the presence of C-O-C in the cellulose biopolymer chain (Dorado et al 2021). Moreover, the intense band centered on 1058 cm -1 showed a high intensity peak which could be associated to C-O-H stretching vibrations linkages in cellulose and hemicellulose or to the presence of C-O-R in alcohols or esters (Ceylan and Goldfarb 2015).…”

“…The OPW were also reused for crude oil production (Pasqualone et al 2016). The energy recovery of OPW can be performed by alcoholic fermentation for bioethanol production (López-Linares et al 2020) or by anaerobic digestion for biogas production (Timpanaro et al 2021), or by thermochemical processes which involve combustion, gasification and pyrolysis (De la Torre Maroto et al, 2020;Dorado et al, 2021;Nunes et al, 2020). Knowing the OPW low biodegradability and the high content of organic matter, the thermochemical conversion of these residues has several advantages over conventional biochemical processes as it helps to reduce the process costs by producing economic-value products applicable in several fields: energetic as biofuels, agronomic as biofertilizers and chemical as source of bioactive molecules.…”

Catalytic effect of alkali and alkaline earth metals on fast pyrolysis pre‐treatment of agricultural waste

“…Then 1 mg ± 0.05 mg of the different biomass samples was placed in the middle of a quartz tube (2 mm diameter and 20 mm long) with a quartz wool base and then introduced into the platinum Pyroprobe autosampler. Pyrolysis took place at 500 °C, at a heating rate of 20 °C/ms for 15 s (the same conditions that were optimized in a previous study) 25 . The experiments were carried out in triplicate for each sample to ensure that the composition of the product could be validated.…”