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Optimization of energy recovery efficiency from sweet sorghum stems by ethanol and methane fermentation processes coupling

2023; Taylor & Francis; Volume: 14; Issue: 1 Linguagem: Inglês

10.1080/21655979.2023.2234135

2165-5987

Bakari Hamadou, Djomdi Djomdi, Ruben Zieba Falama, Roger Djouldé Darnan, Fabrice Audonnet, Pierre Fontanille, Cédric Delattre, Guillaume Pierre, Pascal Dubessay, Philippe Michaud, Gwendoline Christophe,

Biofuel production and bioconversion

Taken separately, a single sweet sorghum stem bioconversion process for bioethanol and biomethane production only leads to a partial conversion of organic matter. The direct fermentation of crushed whole stem coupled with the methanization of the subsequent solid residues in a two-stage process was experimented to improve energy bioconversion yield, efficiency, and profitability. The raw stalk calorific value was 17,144.17 kJ/kg DM. Fermentation step performed using Saccharomyces cerevisiae resulted in a bioconversion yield of 261.18 g Eth/kg DM, i.e. an energy recovery efficiency of 6921.27 kJ/kg DM. The methanogenic potentials were 279 and 256 LCH4/kg DM, respectively, for raw stem and fermentation residues, i.e. energy yields of 10,013.31 and 9187.84 kJ/kg DM, respectively. Coupling processes have significantly increased yield and made it possible to reach 13,309.57 kJ/kg DM, i.e. 77.63% of raw stem energy recovery yield, compared to 40.37% and 58.40%, respectively, for single fermentation and methanization processes.Sweet sorghum stem is a viable feedstock source for efficient coproduction of ethanol and methaneSorghum stems calorific value determination revealed an energy potential of 17.15 MJ/kg DMEnergy recovery by single methanization yielded 18.03% more than ethanol fermentationCoupling processes has significantly increased energy recovery yield and profitability.