Diverse biomass sources from the Canary Islands (vineyard, tomato plant residues, Canary pine needles and Pennisetum setaceum) ) were assessed due to their local abundance, availability, and low supply cost. Based on their physico-chemical properties, various thermochemical processes were conducted to assess their thermal degradation behaviour, using simultaneous thermal analysis, and their potential for energy production. The results indicate that while tomato plant biomass is unsuitable for thermochemical processes because of its elevated ash content and limited volatile matter, the other biomass sources show promising potential for pyrolysis and gasification, characterized by high fixed carbon content and reactivity. The yearly production of residual biomass in the Canary Islands was quantified at 87,253 tonnes. This biomass could generate an estimated 88.5 GWh of electricity annually. Considering that electricity consumption in the Canary Islands reached 8750 GWh in 2023, biomass-derived electricity could contribute approximately 1.0 % to the archipelago's energy needs. These findings highlight the significant role of local biomass resources in advancing renewable energy goals and reduce dependence on non-renewable sources, promoting a greener energy landscape for the Canary Islands.
In a biodiesel production industry a quick monitorization of the reaction extent achieved in the process it is important. The usual way to determine the reaction yield is to analyze the FAME content in the biodiesel reaction product. Analytic methods used, mainly gas chromatography, require previous sample treatment or tedious calibrations. Recently, less complicated analytic methods (nuclear magnetic resonance, infrared spectrophotometry) have been developed but they require costly equipment and analysis. The aim of this paper is to develop a cheap and fast method in order to quantify the FAME content in the reaction mixture from simple dynamic viscosity measurements and then the transesterification reaction yield. Therefore, experimentally obtained correlations from biodiesel proceeding of several oil feedstocks are presented in order to estimate the biodiesel FAME content from its dynamic viscosity, a fast determination parameter.
A selection of some biomass sources from the Canary Islands, such as agricultural biomass (vineyard, VB; tomato plant, TPB), forestry biomass (Canary pine needles, CPB) and invasive species (Pennisetum setaceum, PSB) were evaluated to determine their potential as solid biofuels due to their abundant level, availability and low supply cost. In this work, the main physico-chemical properties (moisture content, ash content, volatile matter, fixed carbon, CHNOS content, mineral content, heating value, density, etc.) of the four biomasses were evaluated. From the results of this study it can be concluded that the TPB is not considered suitable due to its very high ash content and its relatively low content of volatile matter. However, VB, CPB and PSB proved to be potential candidates for energy generation through thermochemical conversion.
The Canary Islands, renowned for their tourism appeal, grapple with a pronounced energy challenge stemming from their geographic fragmentation and heavy reliance on external energy sources, particularly fossil fuels. Moreover, the region's history is marked by recurring energy crises, underscoring the imperative need for a swift and decisive transition towards renewable energy sources. This research examines the potential of waste biomass as a renewable energy source in the Canary Islands. This reliance on non-renewable energy sources leads to increased energy costs and greenhouse gas emissions, making the pursuit of a sustainable energy future a strategic priority in the region. This study proposes to assess the potential of residual biomass from the main crops of the Canary Islands, such as bananas, tomatoes, potatoes, and grapes, for bioenergy production. Statistical data were used to estimate the total availability of residues, while parameters like residue-to-product ratio, moisture content and calorific value were determined to calculate the energy potential of the residual biomass. The research findings reveal that the annual production of residual biomass from the primary crops in the Canary Islands is 234,744 tonnes (111,425 Tn/year from banana cultivation, 52,961 Tn/year from tomato cultivation, 40,102 Tn/year from potato cultivation, and 30,256 Tn/year from grape cultivation). This biomass has the potential to generate around 1.39 PJ of energy, equivalent to approximately 4.79% of the current energy consumption of the archipelago. Considering that renewable sources contribute to only around 20% of the energy production in the Canary Islands, the availability of this resource presents an exceptional opportunity for the region. By harnessing its natural resources, the Canary Islands can pursue sustainable economic growth while simultaneously mitigating negative environmental impacts. Definitely, the assessment of the potential of residual biomass plays a crucial role in evaluating sustainable energy resources and represents an important step towards a more sustainable energy future in the Canary Islands.
This work presents a study of synthesis and characterization of catalysts-based cerium and nickel supported on the pumice stone (Ce/Pumice and Ni/Pumice) to be used in the gasification process of an invasive species present in the Canary Islands, such as Pennisetum setaceum to obtain syngas. Specifically, the effect of the metal impregnated on the pumice, and the effect of catalyst on the gasification process was studied. For this purpose, the composition of the gas was determined and the results obtained were compared with those obtained in noncatalytic thermochemical processes. Gasification tests were performed using a simultaneous thermal analyzer coupled with a mass spectrometer, providing a detailed analysis of the gases released during the process. The results showed that during the catalytic gasification process of the Pennisetum setaceum, the gases produced appear at lower temperatures in the catalytic process that in the non-catalytic process. Specifically, H2 appears at 640.42 degrees C and 641.84 degrees C when Ce/pumice and Ni/pumice were used as catalyst, respectively, compared to 697.41 degrees C for the non-catalytic process. Moreover, the reactivity at 50 % of char conversion for the catalytic process (0.34 and 0.38 min-1 for Ce/pumice and Ni/pumice, respectively) was higher than for the non-catalytic process (0.28 min-1), indicating that the incorporation of Ce and Ni on the pumitic material increases the gasification rate of the char compared to the pumitic support. Catalytic biomass gasification is an innovative technology that can provide new opportunities for research and development of renewable energy technologies, as well as for the creation of green jobs.
Non-polar oil and polar short-chain alcohols, used as reactants in the transesterification reaction, are immiscible. Transesterification reactions can only occur on the phase boundary and they are therefore diffusion-limited. Several methods are employed to overcome the limitation of mass transfer by increasing miscibility and thereby accelerating the reaction. Co-solvents are additional solvents that should be soluble in the oil and alcohol phase; this could lead to an increase in the reaction rate and a reduction in the temperature and the reaction time. This work aims to provide a comprehensive literature review on the influence of co-solvents on the processes of catalysed methanolysis for the biodiesel production. Most authors have not systematically determined and justified the effects of cosolvents. So far it seems impossible to establish which cosolvents are the most suitable for which methanolysis systems. The purpose of this work is to highlight and justify the differences or similarities in co-solvent impacts among the various publications by examining the chemical structure of the respective co-solvents, including the functional groups and the resulting physicochemical properties such as the dielectric constant or the log P value. Besides biodiesel, co-solvents like THF and acetone seems to be the best choices for alkaline methanolysis systems due to successful broadly applications with different oils, catalysts and reaction conditions. Moreover, THF and n-hexane are essentially advisable for in-situ methanolysis.
A packed-bed catalytic configuration reactor using pumice granules loaded with lithium (Li/Pumice) as a heterogeneous catalyst was developed for biodiesel production in continuous. For this purpose, Jatropha curcas oil was used as an alternative feedstock to edible oils and diethyl ether was used as a cosolvent to eliminate the limitations of mass transfer between the phases. In this work, the response surface methodology was applied to optimize the fatty acid methyl esters (FAME) yield in biodiesel production. The flow rate (0.7-1.4 mL min-1), the methanol/oil molar ratio (6:1-20:1) and the cosolvent/methanol molar ratio (0.5:1-1.5:1) were the independent variables studied. The effects of these factors over the FAME yield using Li/Pumice as catalyst were evaluated according to a Box-Behnken design. The optimum conditions for the maximum FAME yield (100%) were 1.4 mL min(-1), 20.0 methanol/oil molar ratio and 0.57:1 cosolvent/methanol molar ratio.
A packed-bed catalytic configuration reactor using pumice granules loaded with lithium (Li/Pumice) as a heterogeneous catalyst was developed for the continuous biodiesel production. For this purpose, Jatropha curcas oil was used as an alternative feedstock to edible oils and diethyl ether was used as a cosolvent to improve the mass transfer between the phases present in the transesterification reaction. The solid catalyst was characterized, and its catalytic activity was evaluated for the biodiesel production. Fatty acid methyl esters (FAME) yield of 100% was achieved under the conditions of 1.4 mL min-1, 20.0 methanol/oil molar ratio, 0.57:1 cosolvent/methanol molar ratio and 40ºC. Moreover, Li/Pumice catalyst shows high stability for the continuous biodiesel production.
Due to the success of the use of energy crop oils in the production of biodiesel, the heavy cultivation of these plants in many countries is being promoted. However, it may lead to the problem with its associated waste shells, which contain low nutrient; consequently, they are not suitable for use as an agricultural fertilizer, and they are abundant in hemicellulose, cellulose, and lignin resulting in difficult to digest or degrade. Thus, a possible solution for this waste is to convert it into carbon-based adsorbents. Specifically, activated carbon is a product with a high added value, widely used material due to its adsorbent properties. These adsorbents could be used for reducing the free fatty acids content presents in oils intended for the biodiesel production. The presence of free fatty acids in the oils is undesirable for biodiesel production due to a performance reduction in the transesterification reaction. The aim of this work is to use biomass waste such as Jatropha curcas and Pongamia pinnata shells for the preparation of carbon-based materials (activated carbons, Ca(OH)2 supported on activated carbons and charcoals) and to study the possibility of using them as adsorbents for reducing the free fatty acids content of Jatropha curcas and Pongamia pinnata oils.
In this work, the anaerobic digestion of three microalgae ( Chlorella sp., Nannochloropsis sp., and Scenedesmus sp.) and their residues, resulting from the oil extraction process and the in situ transesterification reaction for biodiesel production, using two inoculums (sewage sludge and poultry manure) for biogas production was investigated. It was found that the biogas production from digestion of oil-extracted microalgae residue with sewage sludge reached values similar to those obtained with raw microalgae (around 500 NL kg −1 VS). Both the volume of biogas generated from the microalgae residue from the extraction process of its oil and the quality of the biogas produced reflect the value of this residue to be valorized by anaerobic digestion. This approach based on a biorefinery concept and focusing on the anaerobic digestion process could be a key technology for energy production from biomass.
Cu/TiO2 photocatalysts can be considered a promising low-cost alternative to the well-known Pt/TiO2 system for hydrogen production under UV-Vis irradiation.
TEACHING SUPPORT PROGRAM THROUGH INFORMATION AND COMMUNICATION TECHNOLOGY (ICT) TOOLS AT THE UNIVERSITY OF LA LAGUNA: AN OVERVIEW
OVERVIEW OF EDUCATIONAL INNOVATION THROUGH MASSIVE OPEN ONLINE COURSES AND SUPPORT OF INFORMATION AND COMMUNICATION TECHNOLOGY AT THE UNIVERSITY OF LA LAGUNA
The increasing importance of sustainability in energy production has led to a global commitment to the use of fuels derived from renewable biological sources, such as biodiesel produced from plant crops or biomass residues, that do not compete with human food for their production. For a biofuel to be considered biodiesel, it must satisfy the specifications described in the UNE 14214, with the UNE-EN 14103 referring to the determination of fatty acid methyl ester content. This standard applies gas chromatography as an analytical technique. Gas chromatography is a widely used technique in the analysis of methyl ester although it has a number of drawbacks such as: long analysis times, a high consumption of high-quality gases and internal standards, does not allow the analysis of different compounds with the same column, etc. From an industrial production point of view, is necessary to know the fatty acid methyl ester content in biodiesel samples quickly. This paper studies the development of an analytical method using Fourier transform infrared spectroscopy (FTIR) as alternative to gas chromatography (GC), since it is a simple, rapid, and precise analytical technique to quantify fatty acid methyl ester content in biofuel samples.
Expectations for better performance in terms of teaching and producing competent college graduates are increasing. The need for continuous quality improvement in higher education is clear. At the University of La Laguna, the results of the degrees related to academic performance, main indicators and satisfaction of the most significant interest groups are periodically analyzed by those responsible for the centre/title and their quality commissions, monitoring their evolution for continuous improvement. The aim of this work is to compare the different indicators and results of the degrees taught at the Higher Polytechnic School of Engineering and Technology in order to analyze the differences between them and to examine the need to propose measures for continuous improvement.
Innovation is a fundamental aspect in the development processes and improvement of the quality of any organization as it allows to correct deficiencies or weaknesses of the system, or highlight its potential, through the timely incorporation of methodological, organizational innovations, technological, etc., evaluating the effect of them and integrating them in their ordinary operation. In this paper an initiative developed at the University of La Laguna about calls for educational innovation projects to teaching is presented. The purpose of this paper is to analysis, on the one hand, the innovation project modalities and thematic areas object of the calls; on the other hand, the number and type of project requested by the teachers; as well as the evolution and/or changes observed since the call for Educational Innovation Projects from the 2013/2014 academic year to the current one.
Pumice, a natural porous silica material, exchanged with potassium is an efficient heterogeneous particulate catalytic material for triglycerides and free fatty acids transesterification reaction from sunflower oil and waste frying oil at low temperature. In this work, a packed-bed catalytic configuration reactor using this catalytic material was developed for biodiesel fuel production from sunflower oil and frying oil feedstock. Reactor operation variables as methanol/oil molar ratio, catalyst amount, reaction time, and reaction temperature were studied. Results were compared with those obtained from the same transesterification reaction proceeding in a slurry batch reactor. The packed-bed catalytic reactor configuration can be useful in order to minimize catalyst mechanical damage occurring in the slurry reactor due to continuous stirring. The possibility of using a packed-bed reactor shows some advantages because the catalyst stays confined in the reactor bed and the reaction products can be easily separated, besides the mechanical stability of the catalyst particles is achieved.
Waste oils are a promising alternative feedstock for biodiesel production due to the decrease of the industrial production costs. However, feedstock with high free fatty acids (FFA) content presents several drawbacks when alkaline-catalyzed transesterification reaction is employed in biodiesel production process. Nowadays, to develop suitable processes capable of treating oils with high free fatty acids content, a two-step process for biodiesel production is being investigated. The major problem that it presents is that two catalysts are needed to carry out the whole process: an acidic catalyst for free fatty acids esterification (first step) and a basic catalyst for pretreated product transesterification (second step). The use of a bifunctional catalyst, which allows both reactions to take place simultaneously, could minimize the production costs and time. In the present study, the behavior of pumice, a natural volcanic material used as a heterogeneous catalyst, was tested using oils with several FFA and water contents as feedstock in the transesterification reaction to produce biodiesel. Pumice as a bifunctional solid catalyst, which can catalyze simultaneously the esterification of FFA and the transesterification of fatty acid glycerides into biodiesel, was shown to be an efficient catalyst for the conversion of low-grade, nonedible oil feedstock into biodiesel product. Using this solid catalyst for the transesterification reaction, high FAME yields were achieved when feedstock oils presented a FFA content until approximately 2% wt/wt and a water content until 2% wt/wt.
Biodiesel can be produced from ecological friendly processes using edible or waste vegetable oil. Actual production processes can be improved by using heterogeneous catalysts for transesterification reaction activation at low temperature. Few structured or particulated solids with high catalytic activity for biodiesel production reaction have been studied in bibliography. In this work, a microstructured catalyst based on catalytically active pumice material has been developed. Catalytic particles have been made with the shape of an organic template used as former. A novel methodology was used to control the fabrication of pumice-based heterogeneous catalysts as an effective way to improve their efficiency in the production of biodiesel in a continuous packed-bed industrial reactor. The catalytic packed bed reactor configuration studied shows high yields in biodiesel production, obtaining advantages from the microstructural engineering of the catalytic material.
Heterogeneous catalysis is widely applied in industry due to important advantages it offers to chemical processes such as improved selectivity and easy catalyst separation from reaction mixture, reducing process stages and wastes. This is the reason why nowadays heterogeneous catalysts are being developed to produce biodiesel. Several catalytic materials have been showed in bibliography: acid solids capable to carry out free fatty acids esterification reaction, base solids which are able to carry out triglycerides transesterification reaction and bifunctional solids (acid–base character) which show ability to simultaneously catalyze esterification and transesterification reaction. This review discusses the latest advances in research and development related with heterogeneous catalysts used to produce biodiesel.