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Here, we report the optimization of scrap tire rubber (STR) pyrolysis in a fixed-bed reactor for the production of pyrolytic oil (py-oil). Special attention was focused on determining the effects of the temperature and gas residence time on the py-oil and aromatic yields, as well as the optimal range of operating conditions for their maximization. For that purpose, an experimental 4 × 3 factorial design was applied. The maximum py-oil yield obtained was 42.6 mass% at high temperatures and short gas residence times (560–600 °C and 10–18 s, respectively). In contrast, the maximum aromatic concentration (25.6 mass%) was obtained at moderate operating conditions (450–500 °C and 18–20 s). The analysis of variance revealed that the temperature is the most statistically significant variable in py-oil production while, for the nitrogen volumetric flow, only a combined effect with the temperature was observed. In contrast, in terms of the aromatic yield, both the temperature and gas volumetric flow were found to be statistically significant variables. The models provided determination coefficients (R2) close to 0.90, indicating good precision in the predictions.

This paper reviews the sector of waste-to-energy looking at the main processes and feedstock involved. Within this, incineration, gasification, pyrolysis, anaerobic digestion and hydrothermal liquefaction are named and discussed. Through the discussions and scrutiny, manure is highlighted as a significant source of ammonia, methane, and nitrogen oxides emission, estimated to be 40%, 22.5% and 28% respectively of the total UK's anthropogenic emissions. Manure, and indeed the pollution it poses, are shown to remain largely ignored. In waste to energy processing, manure is capable of providing biogas for a number of pathways including electricity generation. Anaerobic digestion is highlighted as a suitable process with the crucial capability of drastically reducing the pollution potential of manure and slurry compared to no processing, with up to 90% reduction in methane and 50% reduction in nitrogen oxide emissions. If the majority of the 90 million tonnes of manure and slurry in the UK were to be processed through biogas harvesting, this could have the potential of producing more than 1.615 TWh of electricity. As such, the economics and legislation surrounding the implementation of anaerobic digestion for manure and slurry are discussed. In the end, restraining factors that limit the implementation of anaerobic digesters on farms in the UK are discussed. These are found to be mainly capital costs, lack of grants, insufficiently high tariff systems, rather than low gas yields from manure and slurry.

International audience; This research deals with the catalytic behavior of the methane steam reforming reaction over a new Ni-exsolved Ruddlesden-Popper manganite during prolonged reaction time (up to 100 h) with special focus on the possible carbon deposition and H2S poisoning. La1.5Sr1.5Mn1.5Ni0.5O7±δ material was synthesized and reduced in diluted hydrogen to induce Ni exsolution. Its catalytic behavior in long reaction times was compared to Ni-impregnated manganite and Ni/YSZ cermet. The catalytic measurements for the steam reforming reaction were carried out at 850 °C in low steam-to-carbon conditions. All materials are susceptible to H2S poisoning (50 ppm), forming undesired sulfide compounds with damaging impact on their catalytic activity. In contrast, during tests without H2S, the activity for cermet and impregnated materials drops at relatively short reaction time due to coking formation, as evidenced by TEM and TGA/MS analysis, while the behavior of new exsolved material remains stable throughout the test. This high stability of the new exsolved catalyst over a prolonged reaction time is a noticeable advantage due to its potential use as SOFC anode fed with natural gas free of H2S.

Investigating the effect of minor components on chemical composition, thermal behavior, and morphology of biodiesel precipitate was the main objective of this study. Blends of distilled palm oil biodiesel (DPOB) spiked with the minor components were prepared and held at 20 °C for 16 h to promote the formation of precipitate. The precipitate was then isolated and analyzed using FTIR, DSC, and SEM/EDS. In contrast to monopalmitin, free steryl glucosides (FSG) were found to induce the formation of multicomponent precipitate. DSC measurements demonstrated the formation of a hydrated phase, called α-gel, when monopalmitin crystallized at high levels of moisture. The α-gel was found to have a lower crystallization temperature than the α form and to be more soluble. Precipitate possessing a flake-like morphology was observed as a result of monopalmitin crystallization whereas a layered structure resulting from extensive sticking of fibrillar aggregates was observed for the precipitate isolated from biodiesel spiked with FSG. Flakes resulting from monopalmitin crystallization were smaller as moisture content increased whereas follicle-like structures were observed for a mass ratio of moisture to FSG exceeding a critical value (>18), in addition to the fibrillar aggregates. Thus, interaction among biodiesel minor components was confirmed to result in precipitate of different sizes shapes, and properties.

A chemical reaction mechanism is proposed to describe the pyrolysis of scrap tire rubber based on the decomposition of their three main polymer compounds (natural, butadiene and styrene-butadiene rubbers). Samples of each polymer were tested separately using differential scanning calorimetry (DSC) at the same operating conditions (heating rate, temperature and atmosphere). The thermograms clearly show that the polymer decomposition takes place in two or three thermal steps. The comparison with the literature allowed associating these steps with depolymerization reactions. The DSC results also allowed determining the kinetic parameters for each reaction considered in the chemical mechanism proposed in this study. Consequently, these were included in a mathematical model developed for a fixed bed reactor (at laboratory-scale) considering mass and energy balances. The experimental conversion obtained in TGA at operating conditions of pyrolysis using scrap tire rubber as feedstock, were successful confronted with those simulated by the mathematical model obtaining a determination coefficient (R2) of 0.97. On the other hand, the mathematical model predicts correctly the influence of the temperature in the product yields, being this variable the most statistically significant in the process, being in agreement with ANOVA results ((p value

Agriculture crop residues represent one of the largest and most diversified sources for producing bio-fuel. However, these resources are highly heterogeneous in terms of the physicochemical properties, spatial distribution and logistics associated costs. These factors are the major bottlenecks hindering the success of biomass energy conversion facilities that use crop residues. The purpose of this study was to develop an integrated GIS-based Fuzzy AHP methodology. This approach combines both spatial and non-spatial factors, such as the logistics factor, transport cost indicators, and technical and geographic restrictions in the study area. The identification of these factors for the actors involved in energy planning provides at a broad-scale multidimensional analysis that allows for the identification of the best sites for a bioenergy plant. This methodology was applied in the department of Santander (Colombia) due to its intense agricultural activity, reflecting the important energy potential of biomass. For three cocoa crop residues evaluated (pruning, rejected and cocoa pod husk), it was possible to identify 12 ideal places to install a bioenergy plant using this approach. The capacity of these biomass plants varies between 52,475 and 146,791 t/year, corresponding to 171 and 479 TJ/year, respectively.

In this work, were studied the thermal and kinetic characteristics of the palm kernel shell (PKS) and empty fruit bunch (EFB) from the African oil palm. Experiments in the inert atmosphere were carried out in a thermogravimetric analyzer. In the kinetic analysis were applied the one-step reaction through iso-conversion methods, mechanism of independent parallel reactions (MIPR), and mechanism of consecutive reactions (MCR). The one-step reaction mechanism overestimated the thermal decomposition of all samples; however, the best was the EFB. The MIPR showed to be representative of the thermal decomposition of all samples, and the proposed correlations between the pre-exponential factor and the heating rate improved the accuracy of the model. The MCR analysis showed that using the same kinetic parameters applied in the MIPR does not affect reliability. Finally, as a conclusion, blending PKS with EFB increase 5% heating value and decrease 50% ash content.

[EN] An original way to perform the exsolution of Ni nanoparticles on a ceramic support was explored for the development of methane steam reforming catalyst in SOFC anode conditions. The n=2 Ruddlesden-Popper (RP) phase La1.5Sr1.5Mn1.5Ni0.5O7 +/-delta has been synthesized by the Pechini method and subsequently reduced with an H-2-N-2 mixture at different temperatures and reducing times to induce the formation of two phases: LaSrMnO4 (n=1 RP) decorated with metallic Ni nanoparticles. Preliminary measurements of catalytic behavior for the steam reforming have been carried out in a reduction-reaction process with a mixture of 82 mol %CH4, 18 mol %N-2 and low steam to carbon ratio (S/C=0.15). The catalyst exhibits a selectivity for CO production (0.97), 14.60 mol % CH4 conversion and around 24.19 mol % H-2 production. Such catalytic behavior was maintained for more than 4 h, with a constant rate of hydrogen production and CH4 conversion rate., The authors acknowledge the financial support of the Colombian Administrative Department of Science, Technology and Innovation COLCIENCIAS (Project #110265842833 "Symmetrical high temperature Fuel Cell operating with Colombian natural gas" (contract #038-2015) and S. Vecino-Mantilla's Ph.D. scholarship (call #647)) and of the Spanish National Research Council CSIC (Project #COOPA20112). The authors are also grateful to UIS' X-Ray Laboratory (Parque Tecnologico Guatiguara) for XRD measurements, UPV's Electronic Microscopy Laboratory for the FESEM analysis, and finally to Margarita Vecino-Mantilla, Carolina Cardenas-Velandia, Santiago Paez-Duque, Ivan Suarez-Acelas (UIS), Maria Fabuel (UPV) and Olivier Gardoll (UCCS) for their contribution to materials synthesis and characterization. As well as Santiago Palencia, Monica Sandoval (UIS) and Caroline Pirovano (UCCS) are warmly acknowledged for useful discussions.

The transformation of dl limonene (mixture of d- and l-form ~ 1:1) that came from the pyrolysis of scrap tires rubber was studied using four heteropolyacid catalysts (H3PW12O40, H3PMo12O40, H4SiW12O40 and H4PMo11VO40) supported on Q-10, SBA-15, MCM-41, and KIT-6. The catalyst activity was measured using a py/GC/FID under a nitrogen atmosphere. The active phase and support were characterized using various technical methods (XRD, Raman, TEM, N2 adsorption–desorption, NH3-TPD, and py-FTIR). The highest weak acidity and largest number of Lewis acid sites promoted the conversion of dl limonene. The isomerization reactions seemed to be more favored than disproportionation reactions. The p-cymene yield was favored, with a high weak acidity and high Lewis/Bronsted acid sites ratio. Moreover, the results show that the use of amorphous support with a higher pore size seems to promote the conversion of dl limonene and the production of p-cymene. HPA-based catalysts with Si are more favorable for converting dl limonene to p-cymene than those with P. For the HPA-based catalysts with P, the highest acidity favors the highest conversion, especially the Lewis acid sites. In this study, the isomerization reactions seem to be more favored than disproportionation reactions.

Implementing anaerobic digestion (AD) in energy production from crop residues requires development of decision tools to assess its feasibility and sustainability. A spatial decision support system (SDSS) was constructed to assist decision makers to select appropriate feedstock according to biomethanation potential, identify the most suitable location for biogas facilities, determine optimum plant capacity and supply chain, and evaluate associated risks and costs. SDSS involves a spatially explicit analysis, fuzzy multi-criteria analysis, and statistical and optimization models. The tool was validated on seven crop residues located in Santander, Colombia. For example, fique bagasse generates about 0.21 million m 3 CH 4 year −1 (0.329 m 3 CH 4 kg −1 volatile solids) with a minimum profitable plant of about 2000 ton year −1 and an internal rate of return of 10.5%. SDSS can be applied to evaluate other biomass resources, availability periods, and co-digestion potential.

Bio-oil is produced by biomass pyrolysis. It contains hundreds of chemical compounds including alkanes, aromatic hydrocarbons, esters, ethers, ketones, aldehydes, acids, alcohols, and phenols. Phenols are compounds of increasing interest; they can be used as feedstock in many industrial applications such as the production of fuel additives, chemical synthesis, or as food antioxidants. Therefore, the valorization of phenols stemming from bio-oil can be an appropriated alternative to reduce the dependence on petro-based phenols in the chemical industry. The most important phenols in bio-oil from agricultural wastes are phenol, guaiacol, cresols, syringol, and xylenol. These compounds were separated by silica gel column chromatography technique, using 3 different solvents: a dichloro-methane—acetone mixture, ethyl acetate, and methanol. Column elution was followed by thin-layer chromatography (TLC). Phenolic fraction was obtained and not individual phenols. This fraction was analyzed using gas chromatography—fame ionization detector (GC—FID) and gas chromatography—gas chromatography—mass spectrometry (GC—MS) with a DB-1701 column, and it was quantified using the relative response factor. Dichloromethane—acetone mixture was the best eluent to obtain this phenolic fraction, specifically during the first three elution steps.

Reactivation and reuse of Spent Bleaching Earth (SBE) to improve Palm Oil Biodiesel (POB) filterability were examined in this study. The SBE was reactivated by washing with hexane, heating treatment at 500 °C and a combination of heating and acid treatment with 0.1 M HCl solution. The resulting adsorbents, denominated as extracted bleaching earth, calcinated bleaching earth (CBE) and regenerated bleaching earth (RBE), respectively, were characterized by several techniques. Virgin Bleaching Earth (VBE) was also characterized. As a result, solvent extraction of residual oil alone was found not to be an effective method for reactivation of SBE. In contrast, the other two methods tested resulted in an adsorbent capable of achieving the needed filterability. Reactivation was found to have a negligible effect on the crystal structure of the parent clay. It was also found not to alter the layered structure of the clay. SBET of CBE (98.94 m2/g) was smaller than that of VBE (160.11 m2/g), but the amount of N2 adsorbed was not significantly different to each other, evidencing that SBE recovered its initial adsorptive properties after being reactivated. Acid treatment led to a rise in SBET of RBE compared to CBE (121.70 m2/g), but it did not significantly increase its adsorption capacity. This was consistent with EDS analyses, where the content of Al+3, Mg+2, and Fe+3, the octahedral cations susceptible of being dissolved during acid treatment, was not statistically different between RBE and CBE.

International audience; The catalytic reforming of pyrolytic oil comes from scrap tires rubber (STR) was studied using as catalyst three different heteropolyacids (HPA) supported on commercial silica (CARiACT Q-10); H3PW12O40 (HPW), H3PMo12O40 (HPMo) and H4PMo11VO40 (HPMoV). A specify attention was given to influence of acidity of catalysts (i.e. strength and acid site types i.e. Lewis and/or Brønsted) on the concentration of cymenes in the pyrolytic oil. The catalytic performance was evaluated in a fixed bed reactor at laboratory-scale equipped with two independent thermal zones; in the first, the STR pyrolysis takes place to produce volatile compounds which, consequently, were transformed in a catalytic zone. The resulting pyrolysis oil in each test was collected in two cooling traps and characterized by GC-MS and GC-FID for the identification and quantification of all aromatic compounds. The results showed a decrease on the pyrolytic oil yield when HPA based catalysts were used, which seems to be promoted by an higher number of Brønsted sites. It has reached an increase in the aromatic concentration, compared to the test without catalyst, of up to 140% for the Molybdenum-based catalysts and close to 89% for the Tungsten-based catalyst. The major compounds obtained were cymenes and its production was closely associated to the type and strength of acid sites. Thus, the highest amount of cymenes (mainly p-cymene) was obtained with the highest number of Lewis sites and the highest ratio of Lewis/Brønsted acid sites, i.e. Molybdenum-based catalysts. On the contrary, the lowest yields were obtained when the Tungsten-based catalyst was used associated to its higher number of Brønsted acid sites and its strong acidity that promote the cracking reactions.

Scrap tyres represent a severe environmental problem that must be solved by developing technologies allowing the processing of high quantities of this residue. This work presents the results of pyrolysis oil and pyrolytic char production by intermediate pyrolysis of rubber recovered from scrap tyres. The influence of process variables such as particle size, temperature and reaction time on the characteristics of the products obtained was analysed. Maximal yields of 52.56 and 39.50 wt% of pyrolysis oil and pyrolytic char, respectively, were obtained, under operational conditions that favoured the production of pyrolysis oil. The products obtained were a pyrolytic char with a maximal surface area of 85.16 m2/g and fixed carbon content of 78.55 wt%; and pyrolysis oil with a higher heating value of 42.94 MJ/kg, real density of 0.948 g/mL, viscosity 2.29×10−3 Pa s and acidity between 0.39 and 1.57 mg KOH/g. The highest total aromatics (benzene, toluene, xylenes and ethylbenzene) yield in pyrolysis oil was obtained at a temperature of 466°C and volumetric gas flow of 155 NmL/min. In addition, at these conditions, the pyrolysis oil having the maximum aromatic yield showed the lowest acidity. Nevertheless, it was observed that the highest pyrolysis oil yield does not necessarily lead to a higher yield of aromatics.

Bio-oil is a mixture of nearly 300 types of organic compounds, including phenols. Phenols are produced during oil refinement and are usually used as fuel additives, food antioxidants and in the synthesis of other chemicals. This study is mainly focused on the extraction of phenolic compounds from bio-oil produced during the pyrolysis of agroindustrial wastes. Bio-oil samples were produced by intermediated pyrolysis of oil from palm empty fruit bunch at 578 °C for 45.6 s using a fixed bed reactor. Under these conditions, the phenol fraction was 13.14 wt%. Two different extraction methodologies were used to obtain a higher phenol fraction of bio-oil: liquid–liquid extraction and reactive extraction. In the first method, an initial liquid–liquid extraction was performed to solubilize the bio-oil in a liquid phase. A second liquid–liquid extraction was subsequently performed with three different organic solvents to maximize the phenolic composition of the fraction. In contrast, the reactive extraction methodology was performed using a NaOH solution to produce phenolates, which are more soluble in water, and thus favor phenol extraction. The resulting phenol extraction yields were not higher than 30 wt% (i.e., a ratio of 1:3.5 of bio-oil and NaOH solution) for the reactive extraction; in contrast, for the liquid–liquid extraction, these yields rose above 68 wt%. The operating conditions favoring this extraction yield included a first extraction with a 5:1 dichloromethane/bio-oil mixture followed by a second extraction with a 10:1 ethyl acetate/concentrated dichloromethane bio-oil mixture.

Palm oil biodiesel (POB) is characterized by a very high precipitate content. Precipitate has caused potential customers to view POB unfavorably, thereby putting the suitability of this biofuel at risk. Therefore, precipitates isolated from POB were characterized in this study. The precipitates were fractionated by column chromatography, and then characterized using thin layer chromatography, FTIR, GC-FID, differential scanning calorimetry, and thermogravimetric analysis. Characterization revealed the preponderant presence of monopalmitin and free steryl glucosides (FSG) in the precipitates. FTIR suggested the presence of acylated steryl glucosides and fatty acid soaps, and thermal analysis revealed the presence of trace contaminants that may have coeluted with the monopalmitin and FSG during fractionation. All these findings should result in the development of techniques to prevent precipitate formation not only focused on the removal of FSG from POB.

Precipitate formation has become an issue of concern for biodiesel producers in the last few years. Precipitate induces a number of undesired consequences. Characterization of precipitate has revealed the preponderant presence of free steryl glucosides (FSG) and monoglycerides (MG). These minor components may interact with moisture, exacerbating precipitate formation. Therefore, the effect of FSG, MG, and moisture content on precipitate formation and filterability of palm oil biodiesel (POB) was investigated. Blends of distilled palm oil biodiesel spiked with the minor components were prepared following a three-factor, five-level center composite design and tested for the cold soak filtration time (CSFT) and the precipitate content. CSFT was found to be influenced only by FSG whereas the precipitate content was found to be influenced by FSG, MG, and moisture. Increasing FSG increased precipitation at low levels of moisture; in contrast, when MG increased, the precipitate content decreased. Interaction with moisture exacerbated precipitation. A model capable of explaining 80% of the CSFT variability and a model capable of explaining more than 96% of the precipitate content variability were obtained using multiple regression analysis.

This research focused primarily on the process optimization for bio-oil production in a pilot-scale batch reactor operating in a fixed bed and using two important agricultural residues from Santander Department in Colombia: sugarcane bagasse (SB) and palm empty fruit bunch (EFB). The Simplex method was applied to develop experimental tests in which three main variables were studied: temperature, gas residence time and particle size. The choice of such variables was based on literature review suggesting that they have a major influence on bio-oil yield. The ranges of the operating conditions were: temperature 460–600 °C, gas residence time 16–80 s and particle size 0.5–1.4 mm. The analysis of variance (ANOVA) shows the temperature being the most influential variable on the bio-oil yield. The other variables were not significant for bio-oil production from intermediate pyrolysis. In the case of SB, the best operating conditions (temperature 560 °C, gas residence time 77 s and particle size 0.5–0.85 mm) resulted in a bio-oil yield of 53.4 wt%, whereas in the case of EFB, the best operating conditions (temperature 540 °C, gas residence time 31 s and particle size

International audience; The metrology and the impact of various parameters and operating conditions on the bulk-to-tube heat transfer coefficients in two-phase bubble columns are investigated on a small-scale mock-up. It is shown that (1) quasi-adiabatic conditions can be reached in the column; (2) the bulk-to-tube heat transfer coefficients for each U-tube downward and upward sections may or may not differ significantly, depending on the way uncertainty of the measurements is estimated; (3) using the different measurements and uncertainty estimates for given conditions, a mean heat transfer coefficient over all tubes is estimated within +/- 5%. The consequences for bulk-to-tube heat transfer coefficient prediction in a larger column are discussed.

Corrigendum to ‘‘Influence of minor components on precipitate formation and filterability of palm oil biodiesel’’ [Fuel 144 (2015) 130–136] Vladimir Plata , Carlos Ortiz , Paola Gauthier-Maradei , Viatcheslav Kafarov a Centro de Investigacion para el Desarrollo Sostenible en Industria y Energia, Universidad Industrial de Santander, Carrera 27 calle 9, Bucaramanga, Colombia b INTERFASE, Universidad Industrial de Santander, Carrera 27 calle 9, Bucaramanga, Colombia

El objetivo de este trabajo es estudiar el proceso de deposicion de parafinas sobre la superficie interna de las tuberias de produccion de petroleo y la influencia de parametros como la velocidad de flujo y la temperatura de la pared sobre el espesor del deposito para un crudo ligero con alto contenido parafinico considerando tres condiciones de frontera sobre la pared de la tuberia; dos de las cuales suponen un perfil de temperatura en la frontera, hecho que no ha sido considerado en trabajos anteriores, y la tercera un valor constante. El analisis se realizo suponiendo condiciones seudo-estables en la fase fluida. El metodo de diferencias finitas se aplico para resolver el sistema de ecuaciones diferenciales y la solucion se llevo a cabo numericamente utilizando el lenguaje de programacion C++. El modelo fue validado a partir de los resultados experimentales reportados por Singh et al. (2000) y posteriormente utilizados para simular el crecimiento de los depositos de parafina como una funcion de la velocidad de flujo y la temperatura de la tuberia. Los resultados mostraron que el aumento de la velocidad de flujo reduce el maximo espesor del deposito, pero este se extiende sobre una distancia mas larga sobre la tuberia cuando se considera una temperatura de pared constante o cuando se considera el gradiente de temperatura axial con pendiente positiva; mientras que se observa el efecto contrario cuando se considera el gradiente de temperatura axial con pendiente negativa.