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During biomass combustion in a grate-fired boiler, each particle undergoes a sequence of different reactions, and the phenomena differ from the conversion of a single, thermally thin, particle. Hence, this paper aims to deepen the understanding of biomass conversion processes and provides valuable insights for advancing biomass-based energy systems. Firstly, the weight loss characteristics of the larger particles of eucalyptus, pine, acacia, and olive samples were investigated at different isothermal temperatures in a purpose-built reactor that simulates the devolatilization process in a controllable manner. As opposed to the thermogravimetric analysis using thermally thin particles, it was concluded that all fuels show that the combustion of large particles does not exhibit separate consecutive conversion stages, due to internal diffusion resistance. Furthermore, it was verified that the devolatilization rate depends mainly on the reactor temperature, and, consequently, the mass-loss profile is independent of the biomass type. In addition to these experiments, the composition of the gases over the devolatilization period was analyzed for the main fuel used in power plants, eucalyptus. Once again, a strong correlation to the reactor temperature was observed, with CO2 and CO always being the main devolatilization products. The temperature dependence of both compounds presented an increase from 8 to 13% between 600 and 800 °C for CO, while the CO2 yield only slightly increased from 11 to 12%. These observations were essential to identify the transport phenomena effect and the gaseous products released during the biomass combustion. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biorefinery approach for the recovery of resveratrol from eucalyptus residues and cheese whey. • Techno-economic evaluation of the viability of the alternatives under assessment. • Environmental sustainability demonstrated through the development of LCA methodology. • Resveratrol production from eucalyptus residues is the most promising scenario. • Further improvement is needed to decrease the environmental loads of energy needs. Biomass is one of the renewable resources with the greatest potential, not only because of the possibility of energy recovery but also because of its content in components of interest. In this context, the regions of Galicia and Portugal have large areas of land dedicated to forestry, agriculture and livestock, and the large amount of waste generated represents a cost for the producer. The importance of these facts has aroused great interest in society to focus its interest on improving the current situation while seeking a benefit, both environmental and economic, from existing resources. That is why the integration of biotechnological processes and biorefinery for their valorization are considered key aspects in the way of producing bioproducts and bioenergy. This research article proposes a process for producing resveratrol from whey from the dairy industry and eucalyptus residues from forestry exploitation. In order to evaluate its suitability, a techno-economic analysis and an environmental assessment have been carried out using the Life Cycle Assessment (LCA) methodology. The results obtained show the potential of these scenarios both from the economic point of view, by obtaining a minimum sale price of resveratrol to ensure the viability of the process below the market average, and from the environmental point of view, being eucalyptus residues those that result in a lower contribution to the environment per unit of resveratrol produced. Future research should focus on increasing the throughput of the production process to increase its profitability and on reducing energy requirements throughout the process, as these have been the main critical points identified. In addition, following the sensitivity assessment, it has been concluded that opting for renewable energy is the most sustainable option. [ABSTRACT FROM AUTHOR]

The use of biomass as a renewable resource has gained significant attention in recent years due to concerns about climate change and the need for more sustainable energy and materi- als. Visualizing the residual forestry biomass supply chain allows for identifying opportunities and challenges related to feedstock harvesting, availability, and transportation costs. This research aims to suggest a map for the valorization of the residual forestry biomass supply chain to identify better and understand the material, financial, and informational flows and to give important insight into the economic dimension of its valorization (costs) and challenges. To attain this objective, two exploratory case studies were conducted. The findings of this re- search reveal similarities in material flow between a large and small company but a significant difference in transportation expenses. The study also found that farmers and forest owners have a small bargaining power to influence the price of the residues they sell. Therefore, this research contributes to a better understanding of the residual forestry biomass supply chain, enhancing the importance of supply chain maps in overcoming possible bottlenecks and challenges in this sector.

During biomass combustion in a grate-fired boiler, each particle undergoes a sequence of different reactions, and the phenomena differ from the conversion of a single, thermally thin, particle. Hence, this paper aims to deepen the understanding of biomass conversion processes and provides valuable insights for advancing biomass-based energy systems. Firstly, the weight loss characteristics of the larger particles of eucalyptus, pine, acacia, and olive samples were investigated at different isothermal temperatures in a purpose-built reactor that simulates the devolatilization process in a controllable manner. As opposed to the thermogravimetric analysis using thermally thin particles, it was concluded that all fuels show that the combustion of large particles does not exhibit separate consecutive conversion stages, due to internal diffusion resistance. Furthermore, it was verified that the devolatilization rate depends mainly on the reactor temperature, and, consequently, the mass-loss profile is independent of the biomass type. In addition to these experiments, the composition of the gases over the devolatilization period was analyzed for the main fuel used in power plants, eucalyptus. Once again, a strong correlation to the reactor temperature was observed, with CO2 and CO always being the main devolatilization products. The temperature dependence of both compounds presented an increase from 8 to 13% between 600 and 800 °C for CO, while the CO2 yield only slightly increased from 11 to 12%. These observations were essential to identify the transport phenomena effect and the gaseous products released during the biomass combustion.

The use of biomass as a renewable resource has gained significant attention in recent years due to concerns about climate change and the need for more sustainable energy and materials. Visualizing the residual forestry biomass supply chain allows for identifying opportunities and challenges related to feedstock harvesting, availability, and transportation costs. This research aims to suggest a map for the valorization of the residual forestry biomass supply chain to identify better and understand the material, financial, and informational flows and to give important insight into the economic dimension of its valorization (costs) and challenges. To attain this objective, two exploratory case studies were conducted. The findings of this research reveal similarities in material flow between a large and small company but a significant difference in transportation expenses. The study also found that farmers and forest owners have a small bargaining power to influence the price of the residues they sell. Therefore, this research contributes to a better understanding of the residual forestry biomass supply chain, enhancing the importance of supply chain maps in overcoming possible bottlenecks and challenges in this sector. [ABSTRACT FROM AUTHOR]

The Sustainable Development Goals deftned by the United Nations established a roadmap on the way to a sustainable society based on a circular economy in which the residual fractions of process streams emerge as raw materials for the provision of material goods and services. In this context, the approach of biorefineries as the technological scheme for processing integrally renewable resources stands out. Among the different target products, "bioactive" compounds have aroused great interest given their high added value. This work evaluates the environmental profile associated with the valorization of residual lignocellulosic waste streams: olive pruning and eucalyptus residues for the biotechnological production of nisin, an antimicrobial compound produced by Lactoccocus lactis with application in the food preservation and biomedical sectors. Process modelling in combination with Life Cycle Analysis allowed addressing the conceptual design and the environmental assessment of a full-scale production process. As a main conclusion, the technological feasibility of the valorization of waste fractions as sources of fermentable sugars in the biotechnological process has been demonstrated. Moreover, the integral use of the raw materials can allow not only the production of nisin as an economic driver, but also of other biotechnological products such as lactic acid and energy for the self-supply of the process. The main novelty of this manuscript is based on rethinking the valorization of lignocellulosic waste beyond energy recovery to obtain bioproducts with high added value in the market with applicability in the food sector. Although energy recovery is the most widely implemented end-of-life option, the use of lignocellulosic waste as fermentable sugars has been shown to improve sustainability and circularity outcomes. [ABSTRACT FROM AUTHOR]

The present work investigates the gasification of forest woodchips, which also contain needles, branches and cones, in an 85-kW open-top gasifier with 60 %–100 % load. This lower quality fuel has higher contents of ash, bark and fines compared to typical requirements of commercial small-scale gasifiers. The woodchips were utilized in unsieved and sieved (>10 mm) fraction. By using gas analysis and temperature measurements at a high local and temporal resolution, three main novel results were found: 1) The results of this work confirm that preferential paths in the fuel bed, caused by the fines content, led to a worse gas quality. The positive effects of a load reduction (i.e., increasing hydrogen and decreasing tars contents) were not found with the unsieved fuel. 2) Opposite trends for the methane concentration with the load were found with unsieved and sieved fuel. The preferential paths probably prevented the complete decomposition of longer-chain hydrocarbons and increased the intermediate product methane, while the non-methane hydrocarbon content reduced at a similar rate with both fuel fractions. 3) When using unsieved fuel, reducing the load massively decreased the fluctuations of the air mass flow and the total hydrocarbon content. With sieved fuel, however, a satisfying process stability was already achieved in all loads. Therefore, an appropriate load management was identified to enable the utilization of fuels with higher fines contents. With these new findings, forest chips in unsieved and sieved form can be successfully used in small-scale open-top gasification. • First investigation of forest woodchips at different loads in a commercial setup. • Preferential paths in the fuel bed prevent gas quality improvement in partial load. • Opposite trends for CH 4 with load with unsieved and sieved woodchips. • Reducing the load calms the gasification process when using unsieved woodchips. • New thermochemical insights path the way towards using less qualitative fuels. [ABSTRACT FROM AUTHOR]

The actual problems related with the depletion of fossil resources and the accentuated increase of global warming requires rapid shift to renewable and eco-friendly alternatives. Biomass forestry residues are valuable candidates that can be used as sustainable resources. Torrefaction is a mild thermal treatment that can convert biomass into value-added liquid and solid products. Here we performed torrefaction at 250 °C of needles, cones and bark from spruce and pine, as representative coniferous species in Romanian Carpathians. The elemental analysis of solid materials was performed and the calculated O/C and H/C atomic ratios showed that torrefaction placed the solid materials in the region of coals, close to the origin of the Van Krevelen diagram. The calorific values were improved, leading to higher energy density. The energy yield was close to the unit, indicating that torrefaction is a highly efficient process. The liquid products had complex composition, with compounds coming from the compositional and structural changes in the forestry residues. Terpenes are the dominating compounds from volatile extractives. Furans, from which furfural and 5-methylfurfural were the main compounds produced from degradation of hemicelluloses, while phenol derivatives were produced from lignin. Exploratory data analysis revealed differences between samples from spruce and pine but also between needles, cones and bark. [ABSTRACT FROM AUTHOR]

Wood and forestry residues are usually processed as wastes, but they can be recovered to produce electrical and thermal energy through processes of thermochemical conversion of gasification. This study proposes an equilibrium simulation model developed by ASPEN Plus to investigate the performance of 28 woody biomass and forestry residues’ (WB&FR) gasification in a downdraft gasifier linked with a power generation unit. The case study assesses power generation in Iceland from one ton of each feedstock. The results for the WB&FR alternatives show that the net power generated from one ton of input feedstock to the system is in intervals of 0 to 400 kW/ton, that more that 50% of the systems are located in the range of 100 to 200 kW/ton, and that, among them, the gasification system derived by tamarack bark significantly outranks all other systems by producing 363 kW/ton. Moreover, the environmental impact of these systems is assessed based on the impact categories of global warming (GWP), acidification (AP), and eutrophication (EP) potentials and normalizes the environmental impact. The results show that electricity generation from WB&FR gasification is environmentally friendly for 75% of the studied systems (confirmed by a normalized environmental impact [NEI] less than 10) and that the systems fed by tamarack bark and birch bark, with an NEI lower than 5, significantly outrank all other systems owing to the favorable results obtained in the environmental sector. [ABSTRACT FROM AUTHOR]

BackgroundThe development of affordable woody biomass feedstocks represents a significant opportunity in the development of cellulosic biofuels. Primary woodchips produced by forest mills are considered an ideal feedstock, but the prices they command on the market are currently too expensive for biorefineries. In comparison, forestry residues represent a potential low-cost input but are considered a more challenging feedstock for sugar production due to complexities in composition and potential contamination arising from soil that may be present. We compare the sugar yields, changes in composition in Douglas-fir woodchips and forestry residues after pretreatment using ionic liquids and enzymatic saccharification in order to determine if this approach can efficiently liberate fermentable sugars.ResultsThese samples were either mechanically milled through a 2 mm mesh or pretreated as received with the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate [C2mim][OAc] at 120°C and 160°C. IL pretreatment of Douglas-fir woodchips and forestry residues resulted in approximately 71-92% glucose yields after enzymatic saccharification. X-ray diffraction (XRD) showed that the pretreated cellulose was less crystalline after IL pretreatment as compared to untreated control samples. Two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR) revealed changes in lignin and hemicellulose structure and composition as a function of pretreatment. Mass balances of sugar and lignin streams for both the Douglas-fir woodchips and forestry residues throughout the pretreatment and enzymatic saccharification processes are presented.ConclusionsWhile the highest sugar yields were observed with the Douglas-fir woodchips, reasonably high sugar yields were obtained from forestry residues after ionic liquid pretreatment. Structural changes to lignin, cellulose and hemicellulose in the woodchips and forestry residues of Douglas-fir after [C2mim][OAc] pretreatment are analyzed by XRD and 2D-NMR, and indicate that significant changes occurred. Irrespective of the particle sizes used in this study, ionic liquid pretreatment successfully allowed high glucose yields after enzymatic saccharification. These results indicate that forestry residues may be a more viable feedstock than previously thought for the production of biofuels.

Biomass residues from agricultural crop and timber production may be a feasible option for energy production due to their social and environmental benefits. This paper presents an assessment of the annual biomass variation of crop and forestry residues, their availability and potential for energy production purposes. The monthly variation in the availability of primary crop residues is also evaluated. This study further shows the spatial distribution of residues and identifies the areas, where larger amounts are available by techniques of geographic information system. It is estimated that 87.94 megatons of dry matter per year (MtDM/yr) of residues are generated from agriculture crops, of which 37.54 MtDM/yr could be available for the production of energy and/or biofuels. Primary and secondary available crop residues contribute to 30.53 Mt DM/yr and 7.01 Mt DM/yr, respectively. Overall, 95.8% of the total available residues come mainly from maize (43.3%), sorghum (25.5%) and sugarcane (18.1%), followed by wheat (6.3%), barley (1.6%) and beans (1.0%). Total energy potential is estimated at 670.3 PJ/yr, of which 542.5 PJ/yr from primary residues and 127.8 PJ/yr from secondary residues. Forestry residues account for about 1.42 Mt DM/yr with an energy potential of 30.72 PJ/yr. Most of the available crop residues are located in 10 municipalities and the forest residues in another 10 different municipalities. Seasonality of agriculture residues indicates that the large availability of residues is mainly found in January, May, June, November, and December. [ABSTRACT FROM AUTHOR]

Wood and forestry residues are usually processed as wastes, but they can be recovered to produce electrical and thermal energy through processes of thermochemical conversion of gasification. This study proposes an equilibrium simulation model developed by ASPEN Plus to investigate the performance of 28 woody biomass and forestry residues’ (WB&FR) gasification in a downdraft gasifier linked with a power generation unit. The case study assesses power generation in Iceland from one ton of each feedstock. The results for the WB&FR alternatives show that the net power generated from one ton of input feedstock to the system is in intervals of 0 to 400 kW/ton, that more that 50% of the systems are located in the range of 100 to 200 kW/ton, and that, among them, the gasification system derived by tamarack bark significantly outranks all other systems by producing 363 kW/ton. Moreover, the environmental impact of these systems is assessed based on the impact categories of global warming (GWP), acidification (AP), and eutrophication (EP) potentials and normalizes the environmental impact. The results show that electricity generation from WB&FR gasification is environmentally friendly for 75% of the studied systems (confirmed by a normalized environmental impact [NEI] less than 10) and that the systems fed by tamarack bark and birch bark, with an NEI lower than 5, significantly outrank all other systems owing to the favorable results obtained in the environmental sector.

Poplar wood hemicellulose prehydrolysate was used for microbial oil production using an oleaginous microorganism Cryptococcus curvatus. Initially, the effect of substrate concentration and nitrogen content was investigated on synthetic media. Then poplar wood prehydrolysate without detoxification was used as substrate in the fermentation. The result showed that this strain is capable of consuming both hexose and pentose sugars, a challenge in fermentation of hemicellulosic streams. It was able to accumulate 36.98% of lipid and the fermentation resulted in 13.78 g/L of biomass and 5.13 g/L of lipid under optimum conditions after 164 h of fermentation. The lipid product obtained was characterized in terms of their fatty acid profiles. Overall, this study shows that it is possible to produce microbial oil from a sustainable renewable feedstock like poplar wood hemicellulose prehydrolysate. This robust strain used has the ability to grow on industrially produced hemicellulose which can help in the development of an integrated biorefinery, where all the three components of lignocellulosic biomass are utilized. [ABSTRACT FROM AUTHOR]

Abstract The present study reports on the technical, economic and environmental analysis of small-scale gasification-ICE systems integrated into sawmills in Chile. Two scenarios were considered, (i) a 100 kWe system for self-consumption in a sawmill and (ii) a 1000 kWe system for using residues from different sawmills. The gasification system was technically assessed by a comprehensive mathematical model implemented on Aspen One 10.0, while economics were studied by the Levelized cost of electricity (LCOE) and environmental impacts were quantified by a Life cycle assessment of forestry, sawmills and power plant processes. Results demonstrate that heat recovery is critical for the process economy, which exhibits an LCOE between 0.15 and 0.32 USD/kWh, and a return on investment of 6.4 years. Nevertheless, the gasification system is far for being an economically-feasible alternative for Chile, where electricity price is 0.08–0.10 USD/kWh. In contrast to economic assessment, the implementation of the gasification-ICE power plant would be a promising alternative for decarbonization of the Chilean energy matrix, showing a reduction of 93% of carbon emissions versus actual practices (viz. co-firing process). From the environmental point of view, biomass harvesting and transport are the critical stages during the whole life cycle of energy production, regardless of the scenario. Highlights • Technical, economic and environmental analysis of a biomass Gasifier-ICE is presented. • Biomass harvesting and transport are the critical stages during the whole life cycle. • Implementation of gasification into Chilean energy sector seem not economically feasible. • Gasifier-ICE brings an opportunity to diversify the Chilean energy matrix. [ABSTRACT FROM AUTHOR]

The main aim of this work was to systematically investigate the effects of time on hydrothermal carbonization of holocellulose coming from the forestry residues. Based on the results, reaction time has a significant impact on the structural, chemical, fuel characteristics and combustion behavior of hydrochars. With increasing reaction time, holocellulose is gradually converted into the amorphous hydrochars with aromatic structure and abundant oxygen-containing functional groups; the O/C and H/C decrease from 0.85 and 1.60 to 0.23 and 0.71, respectively. The HHV s of some hydrochars have reached the quality grade of medium-high quantity calorific coal. The combustion stage and characteristic parameters of holocellulose are predominantly modified after HTC, and HC-14 could be regarded as a good fuel. Additionally, the structural and chemical formation processes of holocellulose-derived hydrochar are proposed. These results revealed that HTC is an effective and simple strategy for converting holocellulose into functional, value-added, and energy-dense hydrophobic solid fuels. [ABSTRACT FROM AUTHOR]

A techno-economic analysis was conducted to assess the feasibility of using forestry residues with different bark contents for bioethanol production. A proposed cellulosic ethanol biorefinery in Sweden was simulated with Aspen Plus. The plant was assumed to convert different forestry assortments (sawdust and shavings, fuel logs, early thinnings, tops and branches, hog fuel and pulpwood) to ethanol, pellets, biogas and electricity. The intention was not to obtain absolute ethanol production costs for future facilities, but to assess and compare the future potential of utilizing different forestry residues for bioethanol production. The same plant design and operating conditions were assumed in all cases, and the effect of including bark on the whole conversion process, especially how it influenced the ethanol production cost, was studied. While the energy efficiency (not including district heating) obtained for the whole process was between 67 and 69% regardless of the raw material used, the ethanol production cost differed considerably; the minimum ethanol selling price ranging from 0.77 to 1.52 USD/L. Under the basic assumptions, all the forestry residues apart from sawdust and shavings exhibited a negative net present value at current market prices. The profitability decreased with increasing bark content of the raw material. Sensitivity analyses showed that, at current market prices, the utilization of bark-containing forestry residues will not provide significant cost improvement compared with pulpwood unless the conversion of cellulose and hemicellulose to monomeric sugars is improved. [ABSTRACT FROM AUTHOR]

Energy has an essential role in the socio-economic development of a country, therefore reliable and sustainable energy supply is a prerequisite for its prosperity. Strategies that analyze and predict energy demand in the future emphasize that local, renewable and sustainable energy sources should be in the focus of interest. Autonomous Province (AP) Vojvodina is a northern part of Republic of Serbia and an energy-deficient province. Crop residues represent the most abundant and promising biomass type for sustainable energy production in agricultural regions, including Vojvodina. Biomass is most commonly utilized through combustion for heat generation. The aim of this paper is to give an overview of total solid biomass potential (from agriculture, fruit and vine growing, forestry and wood processing) for energy generation in AP Vojvodina. Although this potential was initially estimated at 6.45 Mt per year, after considering all the influencing factors, it was concluded that only 2.45 Mt could be used for energy purposes. Solid biomass potential is equivalent to around 0.8 Mtoe per year and is sufficient to substitute completely solid and liquid fossil fuel consumption in Vojvodina, according to final energy balance of AP Vojvodina. [ABSTRACT FROM AUTHOR]

A multidisciplinary study of the implementation potential of a biorefinery, using forestry residues as feedstock, is performed by assessing techno-economic factors, system integration and feedstock supply. The process is based on biochemical conversion of logging residues to produce ethanol, biogas, pellets, heat and electricity. Nine models were designed in Aspen Plus based on the available feedstock and the required co-products. Focus was on the product ratio of pellets and heat. The net present value of the plants was calculated and thermal integration with district-heating systems in areas with regional feedstock availability was investigated. Also co-location with pulp and paper mills in Sweden was investigated to replace fossil fuels with pellets. Seven of the nine models showed a positive net present value assuming an 11% discount rate and 30% corporate tax. Five counties in Sweden were identified as potential feedstock suppliers to a biorefinery processing 200 kt dry feedstock/y. [ABSTRACT FROM AUTHOR]

Application of microorganisms with ability of using environmental wastes such as lignocellulosic materials for converting them to high-value products is important from economical point of view. Valuable products such as single cell oil (SCO) have a high potential to be used in various industrial fields including biodiesel production. Other important products are polyalcohols like xylitol, which are applicable in the food and pharmaceutical industries. In this study, Rhodotorula yeast was isolated from the leaves of Benjamin. Afterward, SCO production was evaluated in a nitrogen-limited medium, and the obtained oil was analyzed by gas chromatography-mass spectrometery. Moreover, xylitol was produced in a media containing xylose and analyzed by high-performance liquid chromatography technique. The yeast strain was identified using polymerase chain reaction method. SCO and xylitol production was also evaluated in a medium containing lignocellulosic materials and other forestry residues. This strain produced SCO and dry biomass of 9.7 and 16.14 g/L, respectively. In addition, in a medium with 140 g/L of xylose, xylitol production was found to be 49.28 g/L. Among waste materials, lipid content of 49 % on grass hydrolysate was found to be incredible. The obtained strain was identified as Rhodotorula mucilaginosa. The results of this study show that by the isolation of yeast with the potential of making use of waste materials, high-value products can be obtained. Therefore, it can be concluded that the mentioned bioprocess has not only environmental benefits but also is very important from economical view. [ABSTRACT FROM AUTHOR]

The present paper discusses the data obtained from the thermogravimetric analysis and kinetic evaluation of seven different experimental solid biomasses representative of the Euroregion Galicia-North Portugal and commonly found in Europe. The samples comprised three raw, nonwoody biomasses and four additivated batches blended with kaolin and calcium carbonate. A TG-DSC analysis was performed on each sample under an oxidative atmosphere and three heating ratios, and the additives were found to increase the duration of the oxidation of carbon, its heat release, and displaced the reaction of volatile compounds to higher temperatures, while at the same time decreasing the peak heat emission caused by the volatiles up to a 40%. Three isoconversional methods, namely, Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose and Friedman were utilized to determine the activation energy and pre-exponential factor of the fuels, both globally and at intervals during conversion, and the results were found to be similar among the three methods, with values ranging from 47.07 kJ/mol to 228.31 kJ/mol for conversion degrees between 0.1 and 0.9. Fuels mixed with the additives mentioned exhibited lower activation energy values than their raw counterparts, suggesting an enhancement of the combustion conditions. • Experimental solid biofuels were subjected to thermogravimetric analysis. • The behavior of the fuels under an oxidative atmosphere was discussed. • Isoconversional methods were used to determine kinetic parameters. • The effect of blending additives into the fuels was studied. [ABSTRACT FROM AUTHOR]

Highlights: [•] Biochar yield of agricultural residues was dependant on the ash and lignin contents. [•] Development of internal pores and surface area was different between biomass types. [•] Biochar from wood and bagasse developed pores of various sizes and large surface area. [•] The biochar became alkaline (pH 9.3–10.5), except for PKS biochar having a pH of 6.9. [•] Dominant inorganic elements in biochar widely varied between biomass types. [Copyright &y& Elsevier]

[Display omitted] • Hydrogen-rich syngas can be prepared by pyrolysis and in-line reforming of biomass. • The residue from biomass pyrolysis can be used as a catalyst. • NiO can be directly reduced by biochar and high efficiency Ni/Char catalyst can be obtained. • Optimal syngas production of 109.848 mmol/g biomass was obtained over Ni/Char catalyst in the presence of water vapor. A residual biochar-based catalyst has been studied for in-line catalytic reforming process after biomass pyrolysis. Poplar pyrolytic char and Ni/char with different Ni loading were prepared and used as catalysts for producing hydrogen-rich syngas from poplar wood. XRD, BET, SEM, and TEM analysis were used to characterize the synthesized catalysts. The results show that biochar has abundant pore structure and catalytic activity, which is in favor of bio-oil reforming. When loaded with Ni, biochar can also be used as a support, which directly reduces NiO to active Ni and protects Ni from oxidation. Ni/Char catalyst showed better catalytic activity than biochar. A series of experiments have been performed to determine the optimal operating conditions, such as catalytic temperature and water injection flow rate. The experiment results indicated that the best syngas production of 34.321 mmol per 1 g biomass can be achieved with 10 wt% Ni/Char catalyst at 650 °C. When 0.3 mL/min of water was added to the pyrolysis reactor, syngas production was significantly increased to 109.848 mmol per 1 g biomass, owing to the thorough utilization of biological carbon through reaction with water vapor. Therefore, this study points to innovative and effective approaches to make full use of biomass and biomass residues. [ABSTRACT FROM AUTHOR]

Abstract: Effective spatial planning is crucial for cost-effectively and sustainably developing biomass energy resources due to the diffuse nature of biomass and high transportation cost. Using the spatial analysis technology, economic models and scenario analysis, this paper presents a spatial planning framework to identify the appropriate developing areas of biomass energy at regional level. The methodology is applied in a case study of Fujian Province, China. Firstly, spatial distribution of two kinds of biomass resources and the technical potential, i.e. the amount of power generation from agricultural and forestry residues in each supply area, were estimated by incorporating the spatial data and the statistical data. The results indicate that total technical potential of agricultural and forestry residues is estimated at 25.13TWhy−1, equivalent to approximately 19% of total electricity consumption in Fujian in 2010. In the second step, the economic analysis assesses the cost of biomass generation for each supply area on the basis of current market conditions. Ranking of the supply areas is then performed by using the priority development index (PDI), which can measure the priority of each biomass supply area by combining several influencing indicators. Finally, the selection of supply areas for power plants can be carried out according to its order in PDI until the total planed capacity in the region is met. The priority of the subregions and the corresponding cost of biomass generation for different planning scenarios can be explicitly visualized. The methodology can be applied to a wide area and can support the local authorities to define and implement a strategy for future biomass energy development. [Copyright &y& Elsevier]

Abstract: The objective of this study was to explore the magnitude of Zimbabwe's biomass resources available for energy production using thermochemical conversion route. This involved estimation biomass from crops, forestry, livestock and Municipal Solid Residues (MSR). A model for estimating biomass energy potential was developed in Microsoft Excel. The crop and forestry production and livestock data used as a basis of calculations was obtained from FAOSTAT. The biomass residues available for energy production were calculated from residues produced considering economic and environmental concerns associated with the removal of crop residues from land and current residue uses. The energy content was obtained by multiplying the available biomass by specific biomass energy content. The total biomass energy was estimated at an annual average of 413.2 PJ but only 279.5 PJ (23.8% crops, 17.8% crop residues, 45.2% forestry resources, 12.2% livestock residue and 1.0% MSR) is sustainably available. Of this energy 189.3 PJ (26.3% from crop residue, 47.9% from woodfuel, 6.4% from forestry residue, 18.0% from livestock residue and 1.5% from MSR) can be used for energy production without competing for resources with food/feed production and other biomass applications. This can meet approximately 48% of the current energy consumption. [Copyright &y& Elsevier]

Abstract: A comprehensive three-dimensional numerical model is developed to simulate forestry residues gasification in a fluidized bed reactor using Eulerian–Lagrangian approach. The complex granular flow behaviors and chemical reaction characteristics are addressed simultaneously. The model uses an Eulerian method for fluid phase and a discrete particle method for solid phase, which takes particle contact force into account. Heterogeneous and homogenous reaction rates are solved on the Eulerian grid. The numerical model is employed to study the gasification performance in a lab-scale pine gasifier. A series of simulations have been performed with some critical parameters including temperature, equivalence ratio and steam to biomass ratio. The model predicts product gas composition and carbon conversion efficiency in good agreement with experimental data. The formation and development of flow regimes, profiles of particle species, and distributions of gas compositions inside the reactor are also discussed. [Copyright &y& Elsevier]

Abstract: The pyrolysis of several agricultural and biofuel production residues (grape residues, sugarcane residues, dried distiller''s grain, palm oil residues, apple pomace and forestry residue) has been carried out in a pilot bubbling fluidized bed pyrolyzer operating under a range of temperature from 300 to 600°C and two vapor residence times (2 and 5s), with the aim of determining their pyrolysis behavior including products yields and heat balance. The composition of the product gases was determined, from which their heating value was calculated. The liquid bio-oil was recovered with cyclonic condensers. The thermal sustainability of the pyrolysis process was estimated by considering the energy contribution of the product gases and of the liquid bio-oil in relation to the pyrolysis heat requirements. The most promising biomass feedstocks for the sustainable production of biochar were indentified. Furthermore, this study presented the char yield in relation to the excess heat that could be obtained by combusting the gas and bio-oil coproducts of biochar production, as functions of pyrolysis temperature and vapor residence time. [Copyright &y& Elsevier]

Abstract: This paper provides methodology for regional analysis of biomass energy potential and for assessing the cost of the biomass at the power plant (PP) location considering transport distance, transport costs and size of the power plants. Also, methodology for determination of an upper-level price of the biomass which energy plant can pay to the external suppliers has been proposed. The methodology was applied on the case of Croatia and energy potential of biomass in the Croatian counties was calculated, using different methodologies, for wheat straw, corn stover and forestry residues, types of biomass considered economically viable at the moment. Results indicate that the average energy potential of wheat straw is 8.5PJ, corn stover 7.2PJ and forestry residues 5.9PJ. [Copyright &y& Elsevier]

Abstract: Biomass is the major energy source in Ghana contributing about 64% of Ghana''s primary energy supply. In this paper, an assessment of biomass resources and biofuels production potential in Ghana is given. The broad areas of energy crops, agricultural crop residues, forest products residues, urban wastes and animal wastes are included. Animal wastes are limited to those produced by domesticated livestock. Agricultural residues included those generated from sugarcane, maize, rice, cocoa, oil palm, coconut, sorghum and millet processing. The urban category is subdivided into municipal solid waste, food waste, sewage sludge or bio-solids and waste grease. The availability of these types of biomass, together with a brief description of possible biomass conversion routes, sustainability measures, and current research and development activities in Ghana is given. It is concluded that a large availability of biomass in Ghana gives a great potential for biofuels production from these biomass resources. [Copyright &y& Elsevier]

Abstract: We assess the energy contents of agricultural and forestry residues in Spain, and the potential for the generation of electricity from them. The methodology employed is a hierarchical, GIS-based one, and leads through the physical, geographical and technical potential to the economic analysis. The results from the latter are crafted in the form of generation-cost curves, which provide a good indication of how the cost of the energy increases as the generation from these residues does. Geo-referenced data allow for the consideration of the opposing influences on the specific cost of the plant size and the transport costs, which are both incorporated in the model by means of a plant supply area. A representative cost is defined and used to compare costs among biomass sources and combustion technologies. The combined technical potential of agriculture and forestry residues is 118 PJ y−1 (equivalent to 11.25% of the net electric energy generated in Spain in 2008). The economic potential (defined as the potential with a cost smaller than the representative one) is 46.3 PJ y−1 (or 4.43% of net electric energy generated in Spain in 2008). [Copyright &y& Elsevier]

Abstract: The objective of this study is to assess the European (EU27+ and Ukraine) cost and supply potential for biomass resources. Three methodological steps can be distinguished (partly based on studies explained elsewhere in this volume) (i) an evaluation of the available ‘surplus’ land, (ii) a modeled productivity and (iii) an economic assessment for 13 typical bioenergy crops. Results indicate that the total available land for bioenergy crop production – following a ‘food first’ paradigm – could amount to 900 000km2 by 2030. Three scenarios were constructed that take into account different development directions and rates of change, mainly for the agricultural productivity of food production. Feedstock supply of dedicated bioenergy crop estimates varies between 1.7 and 12.8EJy−1. In addition, agricultural residues and forestry residues can potentially add to this 3.1–3.9EJy−1 and 1.4–5.4EJy−1 respectively. First generation feedstock supply is available at production costs of 5–15€GJ−1 compared to 1.5–4.5€GJ−1 for second generation feedstocks. Costs for agricultural residues are 1–7€GJ−1 and forestry residues 2–4€GJ−1. Large variation exists in biomass production potential and costs between European regions, 280 (NUTS2) regions specified. Regions that stand out with respect to high potential and low costs are large parts of Poland, the Baltic States, Romania, Bulgaria and Ukraine. In Western Europe, France, Spain and Italy are moderately attractive following the low cost high potential criterion. [Copyright &y& Elsevier]

Abstract: EU targets and regulations regarding energy production and the reduction of greenhouse gas emissions have been tightening in the 2000s. In Finland the targets are planned to be achieved mainly by increasing the use of biomass. Wood already accounts for a marked proportion of Finnish energy production, but additional reserves are still available. Energy crop production also has considerable potential. Practically all Finnish farmers are also forest owners. Therefore, private forest owners are in a decisive position regarding the supply of energy wood and crops in Finland. In this paper the future supply of biomass is examined according to their past behaviour, intentions and attitudes. Finnish forest owners have a positive attitude towards the use of wood and crops in energy production. Price is becoming more critical as a motive for the supply of energy wood. Recreation and nature conservation play a smaller role than factors related to wood production and forest management as for motives for harvesting energy wood. However, almost a half of forest owners in this study were uncertain of their willingness to supply biomass. This is partly due to limited knowledge of the issues involved in energy wood and agricultural energy crop production and the underdeveloped markets for energy biomass. In order to achieve the targets, supply should be activated by further developing market practices, information, guidance and possibly other incentives for landowners. In general, there is interest among landowners in increasing the supply of energy biomass. However, the growth of supply presumes that production is an economically attractive and competitive alternative, that the markets are better organized than at present, and that more comprehensive information is available about bioenergy and biomass markets and production techniques. [Copyright &y& Elsevier]

Abstract: There is increasing interest in Zimbabwe in the use of renewable energy sources as a means of meeting the country''s energy requirements. Biomass provides 47% of the gross energy consumption in Zimbabwe. Energy can be derived from various forms of biomass using various available conversion technologies. Crop residues constitute a large part of the biomass available from the country''s agriculture-based economy. The potential for energy production of crop residues is examined using data such as estimates of the quantities of the residues and their energy content. The major crops considered are maize, sugarcane, cotton, soyabeans, groundnuts, wheat, sorghum, fruits and forestry plantations. Quantities of residues are estimated from crop yields by using conversion coefficients for the various crops. Long-term crop yields data from 1970 to 1999 were used. Total annual residue yields for crops, fruits and forestry plantations are 7.805Mt, 378kt and 3.05Mt, respectively. The crops, fruits and forestry residues have energy potential of 81.5, 4.9 and 44.3PJ per year, respectively. This represents about 44% of the gross energy consumption in Zimbabwe. The need to balance use of crop residues for both energy purposes and other purposes such as animal feeding and soil fertility improvement is also highlighted. [Copyright &y& Elsevier]

Abstract: The operating conditions for an organosolv (ethyleneglycol) and two alkaline (soda–anthraquinone and kraft) processes for obtaining cellulose pulp and paper from holm oak (Quercus ilex) wood trimmings were optimized. A range of variation for each process variable (viz. temperature, cooking time and soda or ethyleneglycol concentration) was established and a central composite experimental design involving three independent variables at three different variation levels was applied. The results obtained with the three cooking processes used were compared and those provided by the kraft process were found to be the best. Thus, the tensile index values it provided (5.9–16.3Nm/g) were 23.7% and 41.5% better than those obtained with the soda–AQ and ethyleneglycol processes, respectively. Also, the kraft process provided the best burst index, brightness and kappa number values. Based on the optimum working ranges, the temperature and cooking time were the variables resulting in the most and least marked changes, respectively, in pulp properties. [Copyright &y& Elsevier]

China encounters heavy air pollution caused by coal consumption. China and the EU aim to decrease greenhouse gas emissions. Shifting to biogas from residues contributes to solving both problems. This study assesses China's biogas potentials and related water footprints (WFs) and compares results with potentials and WFs for the EU. Starting from a literature review on EU biogas potentials, it analyzes information resulting in a calculation methodology, its validation and application to China. Finally, it estimates WFs and makes a comparative assessment of biogas potentials of the EU and China. In the EU, biogas from agricultural, forestry and other residues might contribute 8% (5300 PJ) to primary energy consumption, in China 10% (13,275 PJ.) In the EU, agriculture contributes 41%, forestry 26%, other residues 23%, and manure 10%. The corresponding results for China are agriculture (67%), forestry (23%), manure (7%) and other residues (3%). In the EU, biogas might contribute 45% to total gas demand; in China more biogas can be produced than consumed in 2018 (185% of demand). The EU results fall in the range of residue potentials from earlier studies. Maize, wheat, barley and rapeseed contribute 78% to the EU agricultural biogas potential. In China, dominant crops are maize (49%), rice (18%), wheat (12%) and seed cotton (6%). For water, there are large differences among WFs of specific crop residues, but also between WFs for EU and Chinese crop residues. Most Chinese crop residues have larger WFs than the EU residues. Biogas from sugar beet residues has the smallest WFs, biogas from tobacco residues the largest. Although using residues for energy does not change total national WFs, it reallocates WFs over main products and residues. The comparative assessment supports better use of biogas potentials from residues with lower WFs and is also applicable for other regions and countries., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

In this study, an experimental approach was utilized to assess the viability of three biomass fuels in a small laboratory-scale combustor. Three feedstocks currently considered as residues were selected based on their widespread presence in the Euroregion Galicia-North Portugal, and some were modified to improve their behavior by removing fine particles or adding substances to increase the melting point of the ashes. The experimental facility was a highly modifiable, fixed-bed combustor with air-staging capabilities and a wide array of sensors intended to measure a large quantity of parameters. A series of tests was performed to cover the widest range of total air flows possible for the facility, with values of 0.223, 0.279 and 0.334 kg/m²s being used, while 30% of the total air flow enters from below the combustion bed and 70% over it. Results from the proximate and elemental analyses show high proportions of ash in every fuel compared to commercial wood pellets, and empirical deposition indexes suggest a high risk of fouling and slagging. Testing confirmed the analysis predictions, resulting in the kiwi- and vine-based fuels not being suitable for a facility without ash elimination systems. Some modifications of the gorse fuel showed improved behavior compared to unmodified gorse fuel, namely, the addition of a 2% mass fraction of CaCO3 and the removal of fine particles. The former prevented ash sintering, and the latter greatly decreased the fouling of the heat exchanger tubes. These results suggest that some of the vegetal species studied might be suitable for their use in small-scale biomass burners, and besides the accuracy of one of the deposition indexes used is confirmed. [ABSTRACT FROM AUTHOR]