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For biogas production, different renewable feedstocks, e.g., feces, manure, silage, industrial by-products, and municipal waste, can be used. Biogas production from various renewable feedstocks has positive socioeconomic and environmental impact. In Europe, biogas is mainly used for generating heat and electricity. It consists of methane (55–70% by volume), carbon dioxide (30–45% by volume), and small amounts of other compounds. In some cases, biogas is upgraded to pure biomethane and utilized as vehicle fuel, instead of fossil fuels, thus reducing the emissions of greenhouse gases. Biomethane can also serve as a platform chemical in chemical and biochemical synthesis to produce value-added products. The additional positive effects of anaerobic digestion of animal manure and slurries are organic waste degradation, reducing odors, and pathogens. Digestate, obtained as a by-product of anaerobic digestion, is rich in nutrients and therefore is applied as fertilizer in agriculture. Biogas production in Croatia is mainly based on manure and by-products from agriculture, food industry, and slaughterhouses. The obtained biogas is mostly used for electricity and heat generation. Potential for large-scale biogas production in Croatia is still insufficiently used, although various renewable feedstocks are available. More rational and focused management of lignocellulosic residues, animal excrements, food processing by-products, and biodegradable fraction of municipal waste could contribute to the development of Croatian biogas sector. Biogas production in Croatia can be affected by the changes of animal breeding capacity due to the struggle to cope with the European Union (EU) standards and prices. Concerning large unused agricultural areas, great potential lies in their rational exploitation for fast-growing biomass, e.g., for energy crops or perennial grasses. This review will discuss the potential of biogas in the industrial and farming sector, current state of biogas production, and various key drivers and barriers influencing biogas production in Croatia.

CELIKTAS, Melih Soner/0000-0003-0597-5133, WOS: 000509317900001, Pressurized Liquid Hot Water (PLHW) process is an essential and new method to remove lignin from biomass for biorefinery applications. in this study, a cascade method was investigated to obtain reducing sugars of switchgrass using optimization of PLHW and enzymatic hydrolysis. Optimization of pressurized liquid hot water and enzymatic hydrolyses were achieved by Box-Behnken design. First, pretreatments including PLHW were carried out step by step, with respect to the independent variables such as temperature (100, 140, 180 degrees C), pressure (100, 150, 200 bar) and time (20, 40, 60 min) at fixed flow rate (2 ml/min). the conditions which give the most optimized reducing sugar were 122.12 degrees C, 100 bar and 50.08 min and optimized fermentable sugar content was measured 107.49 g/l. Then, enzymatic hydrolysis was applied to solid phase with 4.8 pH citrate buffer at 50 degrees C during 24, 48 and 72 h with the help of Novozyme 188 and Celluclast enzymes. the reducing sugar amount obtained from switchgrass with enzymatic hydrolysis was measured 248.23 g/L, which means totally 355.72 g/L.

Publisher Copyright: © 2021 The Authors Biomass is a key variable for crop monitoring and for assessing carbon stocks and bioenergy potential. This study aimed to develop an allometric model for predicting the dry leaf biomass of sisal, an agave plant with crassulacean acid metabolism grown for fibre production in the tropics and subtropics and whose biomass can be utilised as a feedstock to produce biogas through anaerobic digestion. The allometric model was used to estimate leaf biomass and productivity across different stand ages in a sisal plantation in semi-arid region in south-east Kenya (annual rainfall 611 mm and temperature 24.9 °C). Based on a sample of 38 leaves, the best predictor for biomass was leaf maximum width and plant height used as a combined variable in a log-log regression model (cross-validated R2 = 0.96 and root-mean-square error = 7.69 g). The mean productivity in nine 26- to 36-month-old plots was 11.1 Mg ha−1 yr−1, which could potentially yield approximately 3000 m3 CH4 ha−1 yr−1. The leaf biomass in 55 field plots (400 m2 in area) ranged from 2.7 to 42.7 Mg ha−1, with mean at 13.5 Mg ha−1, which equals to 6.3 Mg C ha−1. The yielded allometric equations can be utilised for predicting the leaf biomass of sisal in similar agro-ecological zones. The estimates on plantation biomass can be used in assessing the role of sisal plantations as a regional carbon storage. In addition, the results provide reference on the productivity of agave and crassulacean acid metabolism in semi-arid regions of East Africa, where such reports are few.

The crescent number of scientific articles published per year shows that research on biodiesel continues to play an important role to support the growing demand for this biofuel. The second edition of Biodiesel: An Overview presents the worldwide research in the last 15 years. Microalgae biomass is the most studied raw material alternative in this period and several studies have been carried out to develop basic heterogeneous catalysts for biodiesel production. Concerning to production technologies, supercritical conditions and intensification process have been extensively investigated. The development of new antioxidants additives has focused mainly on biomass-derived formulations and there are few studies on biocide candidates. In terms of pollutant emissions, in general, the studies showed that the addition of biodiesel generates lower concentrations of polycyclic aromatic hydrocarbons (PAH), CO and n-alkanes pollutants, but carbonyl compounds, major ions and NOx are emitted in a higher concentration compared to pure diesel.

Biomass-derived 5-ethoxymethylfurfural (EMF) with excellent energy density and satisfactory combustion performance holds great promise to meet the growing demands for transportation fuels and fuel additives to a certain extent. In this review, we summarized the relative merits of the EMF preparation from different feedstocks, such as platform chemicals, biomass sugars and lignocellulosic biomass. Advances for EMF synthesis over homogeneous (i.e. inorganic acids and soluble metal salts), heterogeneous catalysts (i.e. zeolites, heteropolyacid-based hybrids, sulfonic acid-functionalized catalysts, and others) or mixed-acid catalysts were performed as well. Additionally, the emerging development for the EMF production was also evaluated in terms of the different solvents system (i.e. single-phase solvents, biphasic solvents, ionic liquids, and deep eutectic solvents). It is concluded with current challenges and prospects for advanced biofuel EMF preparation in the future.

Straipsnyje analizuojamos biomasės panaudojimo energijos gamybai iš pirminių ir antrinių žemės ūkio žaliavų likučių galimybės. Tikslas - įvertinti biomasės panaudojimo potencialą energijos gamybai iš žemės ūkio atliekų. Tyrimui atlikti taikyti įvairūs analizės metodai ir panaudoti įvairių šaltinių duomenys. Tyrimo rezultatai parodė, kad padidinti energijos gamybą galima naudojant šiaudų biomasę iš pirminių žemės ūkio žaliavų ir augalinę biomasę iš antrinių žemės ūkio žaliavų. Nustatyta, kad biomasės energijos išeiga iš pirminių žemės ūkio atliekų yra žymiai didesnė nei panaudojus antrines žemės ūkio atliekas. Tai padėjo atskleisti, kad Lietuvoje būtina skirti daugiau dėmesio ir paramos netradicinių energinių augalų tyrimų plėtrai. This study discusses biomass potential utilization for energy production from primary and secondary agriculture residue assessment. The purpose of the research – to carry out an assessment of the biomass utilization potential from agricultural residue. The methodology based on analysing statistical data of Lithuania, to estimate the biomass utilization possibilities from agriculture residue. The research methods involve the methodology for the assessment using the mathematics equations and also based on methods of analysis, synthesis and others to achieve to solve the problem of competition between the food industry and agriculture sectors for the food gap in the near future. The authors determined that the potential energy yield from primary agriculture residue is higher than secondary agriculture residue and primary residue utilization for energy production is more useful than secondary residue. The problem with these results discloses that secondary agriculture residue utilization for bioenergy production needs more support with the development of knowledge and skills in Lithuania, especially should apply to attention to researches of non-traditional bioenergy plants. The results of the paper will be useful for further research in energy and agricultural development.

The present document corresponds to the deliverable D2.1 of the ALTERNATE project, Feedstocks for Alternative Aviation Fuels. It provides information on the selected feedstocks by the EU and the Chinese partners for further examination under ALTERNATE WP2 and WP3.

The combination of wastewater treatment and biodiesel production using algal cultivation was studied in the present work. The two main goals of the work were achieved by the cultivation of freshwater microalgae such as Chlamydomonas sp., Scenedesmus ecornis, and Scenedesmus communis in two different dilutions of fertilizer plant wastewater (FWWD1 and FWWD2) collected from Yara Suomi Oy, Finland. The growth pattern of different algal species in FWWD1 and FWWD2 was observed. The effect of pH on biomass concentration, lipid content, biomass productivity, and lipid productivity by all three algal species in FWWD1 and FWWD2 were monitored. The maximum biomass concentration and productivity were observed in FWWD1 at pH7.5 for Chlamydomonas sp. and at pH 8.5 for S. ecornis and S. communis. The maximum lipid content was detected in Chlamydomonas sp at pH5.5, followed by S. ecornis and then S. communis at pH 7.5 in FWWD2 obtained after co-solvent extraction method. The most significant removal percentage of COD by all algal species were observed in FWWD1, whereas the highest removal percentage of TN and TP were detected in FWWD2, respectively. The fatty acid methyl ester (FAME) characterization of each algal species in FWWD1 and FWWD2 at their optimum pH was investigated to determine the quality of obtained biodiesel.

Biomass is among the common resources in developing countries that could alleviate fuel, energy, and environmental problems. This is due to the abundance of biomass as feedstock for energy production in this region. Though, there are some challenges and limitations to their practical use. This includes low energy densities, high volatile content, low calorific value, etc. Herein, some research works on generation of sustainable energy from agro‐residues through thermal pretreatment (TP) for developing nations are reviewed. The review is carried out using articles available on the ScienceDirect database. TP is normally carried out between the temperature range of 200 and 1300 °C – torrefaction (200–300 °C), carbonization (450–550 °C), pyrolysis (350–700 °C), and gasification (800–1300 °C). The heating rate significantly influences the TP output. The Char yield and calorific value increase with torrefaction temperature (TT), whereas the volatile yield decreases. TT does not have a significant effect on char composition. The effect of temperature on char production is more significant compared with residence time (RT). Some developmental possibilities exist in biomass utilization, especially for developing countries via TP: generation of employment, provision of a cleaner environment, economic diversification, and reduction of the poverty level, among other potential opportunities.

With the increasing attention toward renewable platform chemicals, a considerable amount of reaction pathways are being investigated for the potential of scale-up and industrialization. Heat integration, as a key feature in the field of process engineering, needs to be taken into consideration when developing preliminary reaction networks producing value-added products. In this study, we introduce an optimization-based framework for the simultaneous process synthesis and heat integration with the goal of finding the most profitable biobased platform chemical and its production pathways from a number of alternatives. A process superstructure that consists of master reaction stages and lower-level separation stages is introduced to demonstrate the theory. With a novel variable discretization approach, the problem is formulated as a mixed integer linear programming model to determine the optimal reaction pathways and separation sequences along with the heat integration cascade using simple data. The solutions to the problem reveal key information of the optimal flowsheet such as the maximum economic performance the process can achieve and the minimum cooling and heating duties required resulting from the heat integration analysis. A case study is presented to illustrate the applicability of the proposed approach.

This is the accepted manuscript of the paper "Breeding progress and preparedness for mass‐scale deployment of perennial lignocellulosic biomass crops switchgrass, miscanthus, willow and poplar", published as final paper in "Global Change Biology Bioenergy Volume 11, Issue 1, 08 February 2019, Pages 118–151 https://doi.org/10.1111/gcbb.12566”. Genetic improvement through breeding is one of the key approaches to increasing biomass supply. This paper documents the breeding progress to date for four perennial biomass crops (PBCs) that have high output–input energy ratios: namelyPanicum virgatum(switchgrass), species of the generaMiscanthus(miscanthus),Salix(willow) andPopulus(poplar). For each crop, we report on the size of germplasm collections, the efforts to date to phenotype and genotype, the diversity available for breeding and on the scale of breeding work as indicated by number of attempted crosses. We also report on the development of faster and more precise breeding using molecular breeding techniques. Poplar is the model tree for genetic studies and is furthest ahead in terms of biological knowledge and genetic resources. Linkage maps, transgenesis and genome editing methods are now being used in commercially focused poplar breeding. These are in development in switchgrass, miscanthus and willow generating large genetic and phenotypic data sets requiring concomitant efforts in informatics to create summaries that can be accessed and used by practical breeders. Cultivars of switchgrass and miscanthus can be seed‐based synthetic populations, semihybrids or clones. Willow and poplar cultivars are commercially deployed as clones. At local and regional level, the most advanced cultivars in each crop are at technology readiness levels which could be scaled to planting rates of thousands of hectares per year in about 5years with existing commercial developers. Investment in further development of better cultivars is subject to current market failure and the long breeding cycles. We conclude that sustained public investment in breeding plays a key role in delivering future mass‐scale deployment of PBCs.

The physicochemical properties of biochars derived from rice straw, eucalyptus leaves, and vetiver grass pyrolyzed at 400 °C were investigated. It was found that rice straw biochar (RSB) may possess more acidic functional groups than eucalyptus leaves biochar (ELB) and vetiver grass biochar (VGB) while the specific surface area of VGB was the largest. Cd2+ adsorption characteristics by the three biochars were established under the effects of time, initial pH and concentration of solution. Maximum adsorption capacities of RSB, ELB, and VGB calculated by Langmuir model were 57.87 mg/g, 50.21 mg/g, and 44.09 mg/g, respectively, reflecting adsorption mechanisms may be dominated by chemical reaction than physical interaction. SEM-EDS, XRD, FTIR and XPS were employed before and after adsorption to qualitatively explore possible adsorption mechanisms of the three biochar. It was found that precipitation, ion exchange, complexation and cation π interaction occurred in all the biochars. The relative contribution of the four main mechanisms to total adsorption capacity was quantitatively determined, suggesting precipitation, ion exchange, and cation π interaction were dominated for the three biochar, while complexation accounted for an insignificant part. This study clearly demonstrated mineral constituents of biochar had significant effects on Cd2+ adsorption by plant-based biochars, shedding some light on their future application.

Hydrogen is clean and has much higher energy density than most other conventional fuels in terms of power to mass. Hydrogen can be produced from various biomass, either by biological or thermochemical methods. The present study examines various key aspects like substrate selection, pretreatment processes, influencing parameters on biohydrogen production as well as purification processes, it helps to understand various bottlenecks, challenges and constraints. The efforts that required for the industrial production of hydrogen from biomass and similarly provide a perspective on eventual development in the applied area for the sustainable hydrogen economy.

The present work focuses on the study of the solar pyrolysis of beech wood pellets. The biomass degradation process was modelled in the CFD (Computational Fluid Dynamics) platform ANSYS FLUENT 14.0. The results of simulations were compared to experimental tests conducted in a lab-scale solar reactor in order to validate the CFD model. The biomass pyrolysis was carried out at temperatures ranging from 600 to 2000 °C, at two heating rates: 10 and 50 °C/s. This new 2D single particle model represents a significant improvement of previous simpler version, not only because it allows monitoring the evolution of gas speciation but also because its formulation enables to deal with different types of biomass feedstock. The model structure comprises a multi-step complex kinetic framework that involves competitive reactions –including secondary tar reaction- along with rigorous heat and mass (species) transport inside the particle. On this basis, char, tar and gas predicted yields are compared with experimental data. In addition, the gas composition (CH4, CO, CO2, H2and CxHy) is also compared. CFD results are in good agreement with the experimental values, validating this approach as a useful tool to predict the products yields and their composition when pyrolyzing biomass particles. Furthermore, the model can be used when modelling any process where pyrolysis occurs and it can even be easily coupled to any reactor scale model. Fil: Soria, Jose Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas. Universidad Nacional del Comahue. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; Argentina Fil: Zeng, Kuo. Processes, Materials and Solar Energy Laboratory; Francia Fil: Asensio, Daniela Anabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas. Universidad Nacional del Comahue. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; Argentina. Universidad Nacional del Comahue; Argentina Fil: Gauthier, Daniel. Processes, Materials and Solar Energy Laboratory; Francia Fil: Flamant, Gilles. Processes, Materials and Solar Energy Laboratory; Francia Fil: Mazza, German Delfor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas. Universidad Nacional del Comahue. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; Argentina