Biofuel Production Chain Research Articles

Applications of Machine Learning Technologies for Feedstock Yield Estimation of Ethanol Production

Biofuel has received worldwide attention as one of the most promising renewable energy sources. Particularly, in many countries such as the U.S. and Brazil, first-generation ethanol from corn and sugar cane has been used as automobile fuel after blending with gasoline. Nevertheless, in order to continuously increase the use of biofuels, efforts are needed to reduce the cost of biofuel production and increase its profitability. This can be achieved by increasing the efficiency of a sequential biofuel production process consisting of multiple operations such as feedstock supply, pretreatment, fermentation, distillation, and biofuel transportation. This study aims at investigating methodologies for predicting feedstock yields, which is the earliest step for stable and sustainable biofuel production. Particularly, this study reviews feedstock yield estimation approaches using machine learning technologies that focus on gradually improving estimation accuracy by using big data and computer algorithms from traditional statistical approaches. Given that it is becoming increasingly difficult to stably produce biofuel feedstocks as climate change worsens, research on developing predictive modeling for raw material supply using the latest ML techniques is very important. As a result, this study will help researchers and engineers predict feedstock yields using various machine learning techniques, and contribute to efficient and stable biofuel production and supply chain design based on accurate predictions of feedstocks.

Anhydrous Ethanol Pricing in Economies with an Underdeveloped Biofuels Market: The Case of Mexico

Most gasoline currently consumed in Mexico continues to be oxygenated with Methyl Tert-Butyl Ether (MTBE) despite its proven effects on the environment and human health. Hence, the existence of a regulatory framework on biofuels and various institutional efforts have not been sufficient to develop a national market for anhydrous ethanol use as biofuel. The goal of this research is twofold: one, to review and analyze the governmental actions taken to incorporate bioethanol as a gasoline oxygenate, and, two, to design a tool to estimate the bioethanol price at the Storage and Distribution Terminals of PEMEX (Mexico’s state-owned oil company). A price estimation model for bioethanol was developed through the microeconomic theory of the producer and the indifference price of a product methodology, which calculates the daily price of ethanol in the period 2015–2022; additionally, an MS Excel-based support tool was created for this analysis (namely: the Price-CEM). The analysis showed that incorporating bioethanol into the Mexican energy matrix would require policies of fiscal support for R&D, agricultural waste management and bioethanol production, as well as a new regulatory framework to both gradually eliminate MTBE and establish bioethanol/gasoline blending targets. Furthermore, institutional efforts would also be required to integrate all links in the biofuel production chain, including primary feedstock producers. The cost estimation method and tool have also shown to be valuable instruments to calculate both the prices at which a local bioethanol market would be competitive (with respect to the international market) and the most important cost contributions for local supply chains. This is the first tool to estimate the price of anhydrous ethanol at the local level, which can contribute to identifying opportunities and economic thresholds for the successful development of feasible bioethanol markets in Mexico.

An Assessment of Liquid Biofuel Value Chains from Heavy-Metal Contaminated Feedstock

The present work aims to identify alternative liquid biofuel value chain scenarios utilizing heavy metal (HM)-contaminated biomass feedstocks. The analysis is based on breaking down existing liquid biofuel value chains, focusing on the required adaptations needed for clean biofuel production. State-of-the-art and emerging liquid biofuel production options are reviewed. The potential implications caused by the HM load in the biomass feedstock are analyzed along the whole biofuel production chain, which includes pre-processing, conversion and post-processing stages. The fate of the most common HM species present in contaminated biomass is identified and graphically represented for advanced (second generation) biofuel conversion processes. This information synthesis leads to the description of alternative value chains, capable of producing HM-free biofuel. This work goes a step further than existing reviews of experiments and simulations regarding heavy metal-contaminated biomass (HMCB) valorization to biofuels since feasible value chains are described by synthesizing the findings of the several studies examined. By defining the adapted value chains, the “road is paved” toward establishing realistic process chains and determining system boundaries, which actually are essential methodological steps of various critical evaluation and optimization methodologies, such as Life Cycle Assessment, supply chain optimization and techno-economic assessment of the total value chain.

Characterization and Life Cycle Exergo-Environmental Analysis of Wood Pellet Biofuel Produced in Khyber Pakhtunkhwa, Pakistan

Major objectives of this study were to produce low-emitting wood pellet biofuel from selected agro-forest tree species, i.e., Kikar (Acacia nilotica), Oak (Quercus semicarpifolia), and Mesquite (Prosopis juliflora), grown in the southern part of the Khyber Pakhtunkhwa (KP) province of Pakistan using indigenously developed technology (pelletizer machine). Primary raw material, such as sawdust of the selected agro-forest tree species, was obtained from sawmills located in southern part of KP. Life cycle inventory (LCI) was sourced for entire production chain of the wood pellet biofuel by measuring quantities of various inputs consumed and output produced. In addition, the wood pellets were characterized to examine diameter, length, moisture content, ash content, bulk density, high heating value (HHV), low heating value (LHV), as well as nitrogen and sulphur contents. A comprehensive life cycle assessment was performed for wood pellet biofuel production chain using SimaPro v9.1 software. A functional unit of one (01) kilogram (kg) wood pellet biofuel was applied following a gate-to-gate approach. The results of the present study were in accordance with the recommended Italian standard CTI-R 04/5 except for pellet bulk density and nitrogen content. The bulk density for all wood pellets, manufactured from the saw dust of three different agro-forest tree species, were lower than the recommended Italian standard, while for nitrogen content, the results were higher than the recommended Italian standard. Among the environmental impacts, Kikar (Acacia nilotica) wood pellets were the major contributor to fossil fuel depletion, followed by ecotoxicity, mineral depletion and acidification/eutrophication. This was primarily due to lubricating oil and urea-formaldehyde (UF) resin used as inputs in the wood pellets biofuel manufacture. Likewise, human health and ecosystem quality was also affected by lubricating oil, UF resin, and saw dust, respectively. In cumulative exergy demand of 1 kg wood pellets biofuel, the highest impact was from Kikar wood pellets for non-renewable fossils, mainly due to lubricating oil used. Difference in environmental impacts, damage assessment, and exergy were examined in three different scenarios for major hotspot inputs by reducing 20% lubricating oil in case 1, 20% UF resin in case 2, and without usage of UF resin in case 3, while marked reduction was observed in ecotoxicity, fossil fuel, and mineral depletion, as well as acidification/eutrophication impact category. Moreover, a pronounced reduction was also noted in the non-renewable fossil fuel category of cumulative exergy demand of one kg of wood pellets biofuel produced.

Continuous Valorization of Glycerol into Solketal: Recent Advances on Catalysts, Processes, and Industrial Perspectives

With the global biodiesel production growing as never seen before, encouraged by government policies, fiscal incentives, and emissions laws to control air pollution, there has been the collateral effect of generating massive amounts of crude glycerol, a by-product from the biodiesel industry. The positive effect of minimizing CO2 emissions using biofuels is jeopardized by the fact that the waste generated by this industry represents an enormous environmental disadvantage. The strategy of viewing “waste as a resource” led the scientific community to propose numerous processes that use glycerol as raw material. Solketal, the product of the reaction of glycerol and acetone, stands out as a promising fuel additive capable of enhancing fuel octane number and oxidation stability, diminishing particle emissions and gum formation, and enhancing properties at low temperatures. The production of this chemical can rely on several of the Green Chemistry principles, besides fitting the Circular Economy Model, once it can be reinserted in the biofuel production chain. This paper reviews the recent advances in solketal production, focusing on continuous production processes and on Process Intensification strategies. The performance of different catalysts under various operational conditions is summarized and the proposed industrial solketal production processes are compared.

Techno-Economic Assessment and Life Cycle Assessment of CO2 to Biofuel via Micro-Algae Process

The goal of the work is to assess economic and environmental performance of microalgal biofuel production chain and identify hotspots in terms of CAPEX/OPEX, GHG emissions, energy demand and other environmental impacts. These evaluations are used to assist future R&D and business development directions. The modelled plant has a production capacity of 163 kt-biofuels/year (corresponding to 1 Mta-CO2/year treatment capacity by microalgae). Operational energy demand is around 0.17 MJ/MJ of biofuel. Techno-economic assessment shows that future biofuel production cost would be down to 1190 €/t. It is suggested to focus future R&D on cultivation, HTL and upgrading operations, as well as equipment design of cultivation. Life cycle assessment shows that a GHG emissions reduction of 72% would be reached by micro-algae biofuel, compared to conventional fuel in French electricity mix scenario. When looking into all environmental impacts, there is a trade-off when switching to microalgae-based biofuel, and trade-off seems acceptable. It is suggested to focus future R&D on heat integration of HTL/upgrading, reduction of nutrients and flocculent or research of alternative chemicals with lower environmental impact. Use of affordable blue or green hydrogen would further reduce environmental impacts as well.

Enhancement of biomass conservation and enzymatic hydrolysis of rice straw by dilute acid-assisted ensiling pretreatment

To reduce the cost of lignocellulosic pretreatment, rice straw was ensiled with dilute formic acid (FA, 0, 0.2, 0.4, and 0.6%) for 3, 6, 9, 15 and 30 days, and evaluated its effects on fermentation dynamics, lignocellulosic degradation and enzymatic hydrolysis. The results showed that the application of FA, especially at 0.6% level, reduced total fermentation losses of the resulting silages, as evidenced by low dry matter loss, ammonia nitrogen and ethanol content. Meanwhile, the 0.6% FA application promoted hemicellulose removal (232.41 vs 187.52 g/kg DM) and xylose production (0.35 vs 2.80 g/kg DM). The glucose yield and cellulose convertibility of rice straw increased after 30 days of ensiling, and further enhanced by the 0.6% FA application. In conclusion, the 0.6% FA-assisted ensiling pretreatment improved both biomass preservation, hemicellulose removal and enzymatic hydrolysis of rice straw, which is beneficial to the subsequent biofuel production chain.

Bio-treatment of poplar via amino acid for interface control in biocomposites

Advanced biocomposites reinforced by abundant biomass-derived fillers can add a revenue stream to enhance the economic viability of biofuel production chains and the energy efficiency of the composite industry. However, the low stiffness of biopolymers limits their use in structural applications. Poplar fibers (mesh size: <180 μm, Populus spp.), an abundant waste from the wood industry, were used as bio-filler to fabricate high-performance biocomposites based on polylactic acid (PLA), in which the poplar fibers were modified by an amino acid (l-lysine). As a benefit of the amino acid treatment, the tensile Young's moduli of the lysine/poplar/PLA composites increased by up to 68% with the addition of a small amount of lysine, compared with neat PLA. At the same time, the tensile strength, failure strain, and Young's modulus of the poplar/PLA composites all increased after adding only 0.1 wt % of lysine. It has been observed that the lysine content has a significant effect on the decomposition temperature, complex viscosity, storage modulus, crystallization temperature, and crystallinity of composites. The fracture surfaces of the composites with an optimum lysine content had fewer voids and were more compact compared with composites without any lysine. The pores on the surfaces of poplar fibers became more available for the penetration of PLA molecules as a result of lysine addition. Therefore, this study presents a facile method for reinforcing biocomposites with extremely low-cost and environmentally friendly biofillers.

Brassica carinata-derived biodiesel production: economics, sustainability and policies. The Italian case

Abstract The paper explores the economic feasibility and environmental sustainability of producing second-generation biofuel in Italy from Brassica carinata, a non-edible flowering plant of the Brassicaceae family, in a context of rotation with wheat (and eventually other crops). The framework considered allows to rule out issues of ILUC and is highly relevant in a country where extensive monoculture is extremely widespread and there is a high degree of dependence on foreign imports for both biofuels and biofuels-related raw materials, especially from countries such as Indonesia, where the adverse impacts of first-generation biofuel production on the environment are most felt. Using yield and cost data from 5 experimental fields in Italy and taking into account potential returns from the sale of biodiesel and its by-products, glycerine and expeller/meal, the economic sustainability of the entire biodiesel production chain (cultivation, oil extraction and oil refining) is established. Implementation of the Argonne National Laboratory's GREET life cycle model, suitably adjusted so as to apply it to the BC case, confirms also a high environmental sustainability. The range of positive economic effects and externalities that may be triggered by the development of a BC-derived biofuel production chain justifies some form of policy intervention.

Designing coordination contract for biofuel supply chain in China

To ensure the sustainable supply of agricultural feedstock for biofuel production and improve the performance of biofuel supply chain, coordination along the biofuel supply chain in a random yield environment is studied. Three types of coordination contract are examined, namely, an over-production risk-sharing contract (OPC), an under-production risk-sharing contract (UPC), and a mixed contract (MC) with an asymmetric Nash bargaining model. Though an OPC and a UPC can correct the farmers’ over-production and under-production behavior, the expected increase in profit may not be realized by the biofuel producer or the farmers. The MC is feasible because it achieves an efficient supply chain, where supply chain optimization as well as the interests of all individual actors are respected simultaneously. The proposed contracts are tested with data from the cassava-based biofuel industry in China. The findings help practitioners and policy makers understand when and how to implement coordination contracts to achieve the sustainable supply of agricultural feedstock for biofuel production and supply chain Pareto improvement as well.

Fast measurement by infrared spectroscopy as support to woody biofuels quality determination

The increase in the demand for energy supply during the past few decades has brought and will bring to a growth in the utilisation of renewable resources, in particular of solid biomasses. Considering the variability in the properties of biomass and the globalisation of the timber market, a chemical and physical characterisation is essential to determine the biomass quality. The specific international standards on solid biofuels (ISO 17225 series) describe proper specification and classification of wood chip and pellet, to ensure appropriate quality. Moreover, standard requires information about origin and source of the biomass, normally only to be declared by the producers. In order to fulfill the requirements for the biomass quality, the origin and the source should be assessed, even if currently is hard to determine, in particular on milled or densified biomass. Infrared spectroscopy can provide information on the biomass at the chemical level, directly linked also to its origin and source. This technique is fast and not destructive thus suitable also for online monitoring along the biofuel production chain. In this study, 60 samples belonging to 8 different species were collected and related spectra were acquired using a Fourier transform infrared (IR) spectrometer equipped with a module for solid analysis and analysed by principal component analysis. The results obtained show that the method is very efficient in the identification between coniferous and deciduous wood (99% confidence level) and good results were obtained in the recognition of coniferous/deciduous mixtures, too. Nevertheless, some clear differences have been also noted among intra-class grouping, but additional tests should be carried out. This technique can provide useful information to solid biofuel stakeholders about wood quality and origin, important especially for sustainability issues. Further work will be oriented to the development of IR methodologies for the fast measurement of other important biomass parameters (&lt;em&gt;e.g.&lt;/em&gt;, ash content, high calorific value, nitrogen content, &lt;em&gt;etc&lt;/em&gt;.).

Multielement crystalline and pseudocrystalline oxides as efficient catalysts for the direct transformation of glycerol into acrylic acid.

Glycerol surplus from biodiesel synthesis still represents a major problem in the biofuel production chain. Meanwhile, those in the acrylic acid market are looking for new processes that are able to offer viable alternatives to propylene-based production. Therefore, acrylic acid synthesis from glycerol could be an effective solution to both issues. Among the viable routes, one-pot synthesis theoretically represents the most efficient process, but it is also highly challenging from the catalyst design standpoint. A new class of complex W--Mo--V mixed-oxide catalysts, which are strongly related to the hexagonal tungsten bronze structure, able to directly convert glycerol into acrylic acid with yields of up to 51 % are reported.

ChemInform Abstract: Valorization of Agroindustrial Solid Residues and Residues from Biofuel Production Chains by Thermochemical Conversion: a Review, Citing Brazil as a Case Study

AbstractReview: 225 refs.

Farelo de crambe nas formas in natura ou reduzida em antinutrientes na dieta do jundiá

Este estudo avaliou os efeitos da substituição parcial de farinha de peixe e farinha de carne e ossos por farelo de crambe, sobre o crescimento, enzimas digestivas e parâmetros bioquímicos no jundiá (Rhamdia quelen). Este coproduto agroindustrial foi incluído na alimentação de jundiás na forma in natura ou reduzido em antinutrientes, obtido após a aplicação de tratamento químico ao farelo. A inclusão desses ingredientes foi comparada ao tratamento controle (proteína baseada em farinhas de origem animal) durante nove semanas. Crescimento semelhante ao controle foi observado em peixes alimentados com farelo de crambe in natura ou tratado quimicamente na dieta. A inclusão do farelo in natura reduziu a atividade de protease ácida e colesterol plasmático, mas não alterou os parâmetros bioquímicos hepáticos. Menor concentração de glicogênio e glicose no fígado e aumento na aspartato aminotransferase foi encontrada nos peixes alimentados com farelo de crambe tratado, sinalizando uma condição de carência energética. A similar resposta no crescimento, aliada às leves alterações digestivas e metabólicas com o farelo de crambe in natura em relação ao farelo tratado, pode indicar que, no nível de inclusão utilizado, este ingrediente não necessita de um processo prévio para redução de antinutrientes.

Co-marketing alliances in the Brazilian biofuel sector: An analysis based on strategic alliances

Brazil is among the world’s largest producers of biofuels. This situation stimulates agreements and strategic alliances for cooperation between countries where biofuel feedstocks are scarce and those where they are abundant. Thus, this study aims to analyze the strategic alliances for cooperation between countries for biofuel production. This research study was conducted using information from the website of the Brazilian Ministry of Foreign Affairs, and national and international journals, on strategic alliances for cooperation between Brazil and other countries for biofuel production since 2006. It is known that those involved in the strengthening of strategic alliances for cooperation, can work together through the formation of co-marketing alliances, can contribute to the global development of the biofuel industry. They can also extend this development to other agribusiness chains. Finally, co-marketing alliances lead to actions that benefit all countries and participants in the biofuel production chain, as well as society as a whole.

Valorization of agroindustrial solid residues and residues from biofuel production chains by thermochemical conversion: a review, citing Brazil as a case study

Besides high industrial development, Brazil is also an agribusiness country. Each year about 330 million metrics tons (Mg) of biomass residues are generated, requiring tremendous effort to develop biomass systems in which production, conversion and utilization of bio-based products are carried out efficiently and under environmentally sustainable conditions. For the production of biofuels, organic chemicals and materials, it is envisaged to follow a biorefinery model which includes modern and proven green chemical technologies such as bioprocessing, pyrolysis, gasification, Fischer-Tropsch synthesis and other catalytic processes in order to make more complex molecules and materials on which a future sustainable society will be based. This paper presents promising options for valorization of Brazilian agroindustrial biomass sources and residues originating from the biofuel production chains as renewable energy sources and addresses the main aspects of the thermochemical technologies which have been applied.

Coleção de microalgas de ambientes dulciaquícolas naturais da Bahia, Brasil, como potencial fonte para a produção de biocombustíveis: uma abordagem taxonômica

O presente trabalho envolveu a identificação taxonômica de espécies nativas de microalgas (isoladas de ecossistemas dulciaquícolas localizados nos arredores de Salvador, Bahia) integrantes da Coleção de Microalgas dulciaquícolas do LABIOMAR/IB/UFBA, visando estudos taxonômicos mais aprofundados (ultraestruturais e moleculares) e experimentos que possam avaliar sua capacidade para suprir cadeias produtivas de biocombustíveis. As coletas foram realizadas nos arredores de Salvador, Bahia, Brasil. A identificação das espécies foi efetuada com base em caracteres morfológicos. Foram identificados 19 táxons, 12 em nível de espécie e nove em nível de gênero, sendo 14 Chlorophyceae (Chlamydomonas sp1, Chlamydomonas sp2, Chlamydomonas sp3, Chlamydocapsa bacillus (Teiling) Fott, Chlorococcum sp1, Chlorococcum sp2), Coelastrum indicum Turn.. Coelastrum microporum Nägeli, Desmodesmus brasiliensis (Bohl.) Hegew, Scenedesmum obliquus (Turpin) Kütz, Ankistrodesmus falcatus (Corda) Ralfs, Ankistrodesmus fusiformis Corda, Kirchneriella lunaris (Kirchner.) Möbius, Pseudokirchneriella subcapitata (Korshikov) F. Hindák), três Trebouxiophyceae (Botryococcus braunii Kütz., Botryococcus terribilis Komárek et Marvan e Chlorella vulgaris Beijerinck), uma Bacillariophyceae (Nitzschia sp.) e uma Cyanobacteria (Synechocystis sp.).

A comparative study of small-scale rural energy service pathways for lighting, cooking and mechanical power

The strong international growth of biofuels in the last decade brought the interest in bioenergy back on the agenda. While many life cycle assessments for biofuels mainly focus on environmental impacts and costs, over the last decade especially the energy balance of biofuel production chains has been a major point of criticism. This study applies a specially adapted and LCA-based analytical framework for rural energy service pathways (RESPs) to compare the use of Jatropha plant oil and biogas with other small-scale RESPs for lighting, cooking and mechanical power. The aim is to analyse their technological feasibility and economical viability by comparing the energy and cost efficiency. Results show strong differences for the investigated plant oil production and processing pathways, while the comparison with a baseline and a competitive renewable energy scenario reveals a weak performance of plant oil and even biogas in the categories of lighting and cooking. The potential for mechanical power depends largely on the careful optimisation of the energy service pathway by balancing the capital, energy, labour, and transport intensity. For the present case, the village scale production of Jatropha plant oil and biogas and their simultaneous use in a dual fuel engine to locally provide power and electricity would be the service pathway with the highest potential in terms of energy and cost efficiency.

Taking into account water use impacts in the LCA of biofuels: an Argentinean case study

The assessment of biofuels has until now mainly focused on energy demand and greenhouse gas emissions. Only little attention has been given to other impacts, although the general importance of water use for the life cycle assessment (LCA) of agricultural products has been recognized in recent publications. The aim of this work is to assess in detail the water consumption along a biofuel production chain taking into account irrigation efficiencies, levels of water scarcity, and type of feedstock, and to integrate those results in a full LCA. Furthermore, we compare the results for biofuels from various feedstocks and regions with conventional petrol. We calculate the water consumption and overall life cycle assessment results in a case study for the production of methyl ester from irrigated and non-irrigated rapeseed. The results are compared with other irrigated and non-irrigated biofuels based on different feedstocks. Water consumption in biofuel production chains based on non-irrigated crops does not vary greatly and is in the same range as for fossil fuel. In contrast, as a consequence of irrigation, agricultural water consumption dominates the overall results of all irrigated crops. Consequently, the level of water scarcity plays a key role for the LCA results. In our case study, the environmental impacts of methyl ester from irrigated rapeseed in a water-scarce region, measured in aggregated Eco-Indicator 99 scores, are almost doubled by water consumption. Variations in irrigation efficiency, however, are of little influence on the results, as the assessment method used here is based on consumptive water, which depends mainly on the evapotranspiration of the crop. The focus on greenhouse gas emissions of the main regulatory schemes neglects other relevant environmental impacts and may provide the wrong incentives. Water consumption may thus become a major concern, offsetting the benefits of biofuel use with respect to climate change.

Approach for a pro-active emerging risk system on biofuel by-products in feed

Worldwide biofuel products have rapidly entered the market and consequently so did the availability of their by-products for feed production. A pro-active emerging risk system for biofuel by-products is essential in order to prevent the occurrence of emerging hazards in feed and livestock production. In the current study, two biofuel by-products were elaborated upon, namely Dried Distillers Grains with Solubles (DDGS) resulting from bioethanol production and microalgae slurry resulting from biodiesel production. A holistic approach was used in which both factors from within the feed chain as well as outside the feed chain were incorporated. A list of critical factors linking dynamics in the biofuel production chain with possible feed safety risks was established after consultation of experts in in-depth interviews. Subsequently, a workshop was organized to determine the most important critical factors. Indicators (signals that indicate a change in critical factors) and information sources were linked to these factors for the individual cases. Based on expert judgment, the most important critical factors identified for the two selected cases were: chain complexity, composition of the feed product, origin of raw materials and climate change. Ranking of the indicators showed that in both cases the number of chain stages was the most important general indicator for feed safety risks. The study showed that following this approach resulted in the selection of critical factors and indicators for emerging feed safety risks related to the use of biofuel by-products. Once critical values (upper and/or lower limits) are assigned to the indicators, the system can support decisions to take actions in an early stage in order to prevent emerging risks in feed due to the use of DDGS or microalgae slurry.