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    Anaerobic digestion of dry palms from five cultivars of Algerian date palm (Phoenix dactylifera L.) namely H?mira, Teggaza, Tinacer, Aghamou and Takarbouchet: A new comparative study
    (Pergamon-Elsevier Science Ltd, 2023) Djaafri, Mohammed; Drissi, Aicha; Mehdaoui, Sabrina; Kalloum, Slimane; Atelge, M. R.; Khelafi, Mostefa; Kaidi, Kamel
    The lignocellulosic properties of date palm waste (dry palm) differ significantly from one cultivar to another, which affects the anaerobic digestion (AD) process. This study is believed to be amongst the first to evaluate the influence of date palm cultivars on the biomethane yield in order to offer an annual, continuous and cost-effective biogas production model. In this work, 5 cultivars from date palm waste namely; H'mira (H), Teg-gaza (Tg), Tinacer (Ti), Aghamou (Ag) and Takarbouchet (Tk) were evaluated for biogas production. All experi-ments were performed for 45 days with 5 reactors in triplicate under mesophilic conditions (37 degrees C). The highest methane yield of 231.87 ml of CH4/g of Volatile Solid (VS) was obtained with the Ag cultivars with a difference that varied between 37% and 62% depending on the cultivar type. These results indicate that the date palm cultivars massively influence the biomethane yield, it may give an opportunity for researchers to select the most suitable cultivars for methane production and provide opportunities to valorize other cultivars on other bene-ficial uses, such as adsorption, thermal insulation, or charcoal production etc.
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    Effect of stirring speeds on biodiesel yield using an innovative oscillatory reactor and conventional STR (A comparative study)
    (Elsevier Sci Ltd, 2022) Khelafi, Mostefa; Djaafri, Mohammed; Kalloum, Slimane; Atelge, M. R.; Abut, Serdar; Dahbi, Abdeldjalil; Bekirogullari, Mesut
    This paper aims to study the effect of stirring speed on biodiesel yield using an innovative oscillating reactor compared to the conventional stirring tank reactor. The efficiency of the invented reactor was compared with the conventional system, employing two catalysts (a homogeneous catalyst and a heterogeneous bio-catalyst). The obtained results showed that under low agitation speed of 50 rpm, the invented oscillating reactor is more efficient than the conventional system with a biodiesel yield of 93% compared to 90.13% using the heterogeneous catalyst and 93.53% compared to 92.7% using the homogeneous catalyst respectively. As for the higher stirring speeds, the conventional system was found to be slightly more efficient than the oscillating reactor when using the heterogeneous biocatalyst (96.03% against 94.42%) while the contrary was observed when using the homogeneous catalyst (94.43% against 95%). However, this slight increase in the biodiesel yield at higher speeds results in increasing production costs. This indicates that biodiesel production using the innovative oscillating reactor at low speeds is more economically viable. The characteristics of the produced biodiesel using the invented reactor were in agreement with the ASTM D6751 biodiesel standards. Moreover, a two-way ANOVA analysis was conducted to compare between groups that have been split on two independent variables as reactor type and stirring speed. The statistical analysis proved that the invented oscillating reactor performs better when using heterogeneous catalysts at low stirring speed levels. This study suggests that the biodiesel yield of the innovative reactor can be further enhanced by introducing a baffle system which provides a relatively larger contact surface area. Similarly, synthesis of other heterogeneous bio-catalysts derived from the date seed of another date palm cultivar can be tested to further improve the biodiesel yield.
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    Öğe
    Semi-continuous mesophilic anaerobic digestion of date palm (Phoenix dactelifyra L.) leaflets of the H'mira cultivar from the Adrar region of Southern Algeria using an alkaline pre-treatment
    (Elsevier, 2024) Salem, Fethya; Djaafri, Mohammed; Kaidi, Kamel; Atelge, M. R.; Khelafi, Mostefa; Tahri, Ahmed; Soumia, Balla
    This research paper aim to investigate the enhancement potential of mesophilic Anaerobic Digestion (AD) of Algerian date palm (Phoenix dactylifera L.) leaflets from H'mira cultivars using an alkaline pretreatment approach. The experiment was conducted for the first time in semi-continuous digesters. NaOH was applied at various percentages (6 %, 12 % and 18 %) to chemically pretreat the substrate for 5 days at 37 degrees C. The chemical pretreatment results were interpreted for the first time with in-depth FTIR spectroscopic analyses. The Hydraulic Retention Time (HRT) was fixed at 15 days, and the Organic Loading Rate (OLR) at 2 g MO/L/day. The results showed that the methane (CH4) production values were stabilized with a clear distinction at averages of 211.85, 177.26, 143.36 and 123.07 ml of CH4/day, i.e. a CH4 yield of 105.92, 88.63, 71.68 and 61.53 ml of CH4/gVS/day for the reactors containing substrates pre-treated with 12 %, 6 %, 18 % NaOH and the substrate without pretreatment respectively. Compared to the substrate without pre-treatment, the CH4 production rates were improved 1.72, 1.44 and 1.16 times for the reactors containing 12 %, 6 % and 18 % NaOH respectively. These findings were perfectly in accordance with FTIR spectroscopy results. These findings demonstrate that the semicontinuous AD process can be an attractive energy recovery solution from such waste compared to batch digesters, (on one day, it produce 77-105 % of the CH4 produced during 21-55 days in batch digesters), as well as the importance of adequate pre-treatment prior to the AD. FTIR Spectroscopic analysis technology can also be widely used to analyze pre-treatment data for lignocellulosic biomass, as it gives very encouraging results.