• Energy Research

Dans ce travail, une nouvelle méthode a été proposée pour la conversion des huiles de cuisson usagées en biodiesel. Une approche en deux étapes basée sur un prétraitement avec AlCl3•6H2O pour convertir les FFA en esters méthyliques pertinents, suivie de la transestérification complète des glycérides, sous catalyse KOH dans une colonne de distillation réactive, a été envisagée. Le prétraitement avec AlCl3•6H2O a permis d'obtenir deux phases différentes : une phase huileuse, riche en FAME et en triacylglycérols et avec une teneur très limitée en eau (100 ppm), et en FFA résiduel (1 mgKOH /goil), et une phase méthanol, dans laquelle la plupart du catalyseur, de l'eau et des monoacylglycérols ont été dissous. Le flux estérifié a été caractérisé par sa composition et utilisé pour obtenir de nouveaux paramètres cinétiques à utiliser dans le réglage de la distillation réactive. La colonne de distillation réactive s'est avérée efficace pour obtenir un flux de biodiesel avec une exigence de pureté conforme aux normes EN14214. L'étape de transestérification a été caractérisée par un besoin spécifique de chauffage de 701,3 kJ par kg de biodiesel produit. En este trabajo, se propuso un método novedoso para la conversión de aceite de cocina residual en biodiesel. Se consideró un enfoque de dos pasos basado en un pretratamiento con AlCl3•6H2O para convertir FFA en los ésteres metílicos relevantes, seguido de la transesterificación completa de glicéridos, bajo catálisis de Koh en una columna de destilación reactiva. El pretratamiento con AlCl3•6H2O permitió obtener dos fases diferentes: una fase oleosa, rica en FAME y triacilgliceroles y con un contenido muy limitado de agua (100 ppm), y FFA residual (1 mgKOH /Goil), y una fase de metanol, en la que se disolvió la mayor parte del catalizador, agua y monoacilgliceroles. La corriente esterificada se caracterizó por su composición y se utilizó para obtener nuevos parámetros cinéticos que se utilizarán en el ajuste de la destilación reactiva. La columna de destilación reactiva demostró ser eficiente en la obtención de una corriente de biodiesel con un requisito de pureza conforme a las normas EN14214. La etapa de transesterificación se caracterizó por un requisito de calentamiento específico de 701,3 kJ por kg de biodiésel producido. In this work, a novel method was proposed for the conversion of waste cooking oil into biodiesel. A two-step approach based on a pretreatment with AlCl3•6H2O to convert FFA into the relevant methyl esters, followed by the complete transesterification of glycerides, under KOH catalysis in a reactive distillation column, was considered. The pretreatment with AlCl3•6H2O allowed to obtain two different phases: an oily phase, rich in FAME and triacylglycerols and with a very limited content of water (100 ppm), and residual FFA (1 mgKOH /goil), and a methanol phase, in which most of the catalyst, water and monoacylglycerols were dissolved in. The esterified stream was characterized by its composition and used to obtain new kinetic parameters to be used in the setting of the reactive distillation. The reactive distillation column was proved to be efficient in obtaining a biodiesel stream with a purity requirement conform to the EN14214 standards. The transesterification step was characterized by a specific heating requirement of 701.3 kJ per kg of biodiesel produced. في هذا العمل، تم اقتراح طريقة جديدة لتحويل نفايات زيت الطهي إلى ديزل حيوي. تم النظر في نهج من خطوتين يعتمد على المعالجة المسبقة باستخدام AlCl3 • 6H2O لتحويل FFA إلى إسترات الميثيل ذات الصلة، يليه التحويل الكامل للغليسريدات، تحت تحفيز KOH في عمود التقطير التفاعلي. سمحت المعالجة المسبقة باستخدام AlCl3 • 6H2O بالحصول على مرحلتين مختلفتين: مرحلة زيتية، غنية بالشهرة وثلاثي أسيل الجلسرين وبمحتوى محدود جدًا من الماء (100 جزء في المليون)، وبقايا FFA (1 ملغ كوه/غويل)، ومرحلة ميثانول، حيث تم إذابة معظم المحفز والماء وأحادي أسيل الجلسرين. يتميز التيار الأستري بتكوينه ويستخدم للحصول على معلمات حركية جديدة لاستخدامها في إعداد التقطير التفاعلي. ثبت أن عمود التقطير التفاعلي فعال في الحصول على تيار ديزل حيوي مع متطلبات نقاء تتوافق مع معايير EN14214. تميزت خطوة التحويل بمتطلبات تسخين محددة تبلغ 701.3 كيلو جول لكل كيلوغرام من الديزل الحيوي المنتج.

Alcohols produced by fermentation of biomass or biowastes are generally referred to as bioalcohols to clearly identify their green origin and to differentiate them from their oil-derived counterpart. Bioalcohols belong to the more general family of biofuels, and they can be employed in the transportation sector, like in the case of bioethanol and biobutanol, or used as building block chemicals like in the case of biomethane. However, different aspects of their production are still considered as a challenge. Recalcitrant structure of the feedstock used and the diluted mixtures obtained from fermentation together with complex thermodynamic behavior require efficient pretreatment methods, complex purification technologies, and suitable control strategies. These aspects are here discussed, emphasizing the achievements and the challenges. The purification of bioethanol by membrane separation and reactive distillation is considered as a case study in order to quantify the intensification procedure and analyze the process performances.

The possibility of breweŕs spent grain exploitation through a sequence of supercritical fluid extraction, acid hydrolysis, and fermentation was considered. All steps have been optimized within an interval of operative conditions, using specific designs of the experiments, and modeled through the Response Surface Methodology. The supercritical fluid extraction was optimized in the pressure range 20–40 MPa and temperature 40–100 °C. A fractional factorial design was applied considering the sulfuric (0.065–0.37 M) and nitric (0.01–0.5 M) acid concentration, and the liquid–solid ratio (8–12 w/w %) as independent factors for the hydrolysis step. The fermentation process of pre-treated BSG was also optimized using the Box-Behnken design with temperature (25–37 °C), inoculum volume (5–15 v/v %), and pH (4.5–6.5) as investigated factors. At optimal conditions, the overall process led to an ethanol yield of 82 % evaluated with respect to the theoretical one. Moreover, all the supercritical fluid extracts were richer in phenolic compounds than the ones obtained by the traditional Soxhlet method.

Abstract The prime aim of this paper is to address the relevant issues associated to the development of neural-based software sensors for monitoring the pollutant emissions coming out from combustion chambers. The objective is to prove the potential of software sensors as alternative monitoring systems to conventional analytical equipment. The preliminary results refer to a 4.8 MW power pilot plant operating at the Enel Santa Gilla Research Center in Cagliari (Italy).

This paper explores the transformation of biowastes from food industry and agriculture into high-value products through four examples. The objective is to provide insight into the principles of green transition and a circular economy. The first two case studies focus on the waste generated from the production of widely consumed food items, such as beer and coffee, while the other two examine the potential of underutilized plants, such as burdock and willow, as sources of valuable compounds. Phenolic compounds are the main target in the case of brewer’s spent grain, with p-coumaric acid and ferulic acid being the most common. Lipids are a possible target in the case of spent coffee grounds with palmitic (C16:0) and linoleic (C18:2) acid being the major fatty acids among those recovered. In the case of burdock, different targets are reported based on which part of the plant is used. Extracts rich in linoleic and oleic acids are expected from the seeds, while the roots extracts are rich in sugars, phenolic acids such as chlorogenic, caffeic, o-coumaric, syringic, cinnamic, gentisitic, etc. acids, and, interestingly, the high-value compound epicatechin gallate. Willow is well known for being rich in salicin, but picein, (+)-catechin, triandrin, glucose, and fructose are also obtained from the extracts. The study thoroughly analyzes different extraction methods, with a particular emphasis on cutting-edge green technologies. The goal is to promote the sustainable utilization of biowaste and support the green transition to a more environmentally conscious economy.

Abstract The purification of bioethanol is traditionally performed by extractive distillation using three column sequences. In the present work new arrangements composed of two columns are considered for the analysis of control properties. The control properties study was based on the controllability properties under open loop operation, followed by the dynamic behavior for common industrial operating disturbances. Simulation results were analyzed by the singular value decomposition technique. The results from the theoretical control properties indicate that the presence of a side stream in the extractive distillation sequences does not necessarily provide operational disadvantages. The results also suggest that control properties are ruled by the kind of solvent used. The best performances were obtained when glycerol is used as entrainer.