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  • Optimization of the oxidative fast pyrolysis process of sugarcane straw by TGA and DSC analyses
    Biomass Bioenergy (IF 3.537) Pub Date : 2020-01-16
    Rondinele Alberto dos Reis Ferreira; Carla da Silva Meireles; Rosana Maria Nascimento Assunção; Marcos Antônio S. Barrozo; Ricardo Reis Soares
  • Drought minimized nitrogen fertilization effects on bioenergy feedstock quality
    Biomass Bioenergy (IF 3.537) Pub Date : 2020-01-11
    Sarah M. Emery; Karen A. Stahlheber; Katherine L. Gross

    Switchgrass (Panicum virgatum) is one of the leading candidates for sustainable lignocellulosic biofuel production in North America. Most current management recommendations for switchgrass include applications of synthetic nitrogen (N) fertilizers to increase production, particularly when grown on marginal lands. However, this management can be costly to growers and have negative impacts on ecosystem functioning. Also, N-fertilization does not always result in higher yield in switchgrass and may have unintended effects on plant biomass quality, including cell wall composition, that can affect the efficiency of fermentation processes for biofuel production. Drought stress may reduce biomass responses to N-fertilization, further reducing the value of fertilizer application. To examine whether N-fertilization and reduced precipitation affected switchgrass productivity and cell wall composition, we conducted a two-year field experiment in mature stands of two switchgrass cultivars grown for bioenergy at the W.K. Kellogg Biological Station Long Term Ecological Research Site in Michigan, USA. Nitrogen was added at a rate of 56 kg N ha−1 (urea and ammonium nitrate), and precipitation was reduced using rainout shelters. Overall, we did not observe any effect of N-fertilization on biomass production. However, under ambient rainfall conditions, N-fertilization altered switchgrass biomass quality by reducing hemicellulose. Reduced precipitation minimized the effects of N-fertilization on switchgrass cell wall composition. Switchgrass is a relatively drought-tolerant species, and our results indicate that this crop will be a viable bioenergy feedstock even in a changing climate. However, in this study, N-fertilization had no effect on biomass quality or quantity under drought conditions.

  • Formic acid pretreatment for enhanced production of bioenergy and biochemicals from organic solid waste
    Biomass Bioenergy (IF 3.537) Pub Date : 2020-01-09
    Alessandra Cesaro; Anna Conte; Hélène Carrère; Eric Trably; Florian Paillet; Vincenzo Belgiorno

    Organic solid waste is one of the most promising feedstocks for the implementation of the circular economy principles in waste management. Its anaerobic treatment can indeed promote organic matter conversion into a number of value-added products as well as energy carriers. However, the identification of sustainable strategies to handle organic solid waste in a biorefinery framework still poses technological as well as economic challenges. The aim of this study was in enhancing the potential of the organic fraction of municipal solid waste (OFMSW) to produce bioenergy and biochemicals by combining dark fermentation with a formic acid pretreatment. Hydrogen yields up to 31.6 ml/gVS were obtained pre-treating the OFMSW with 5% formic acid, at 80 °C for 70 min. Concomitantly, a wide range of metabolites of market significance, including acetic acid, butyric acid and ethanol, accumulated. The concentration of these metabolites further enhanced after the dark fermentation of the pretreated substrates. Experimental tests highlighted the influence of the different pretreatment operating conditions on the relative production of hydrogen and main metabolites as well as the related pathways. It was found that the acid concentration plays a key role in promoting the biological conversion of OFMSW and that the adjustment of the operating temperature and treatment time can be targeted towards the production of either building blocks or energy carriers, so as to ensure the viability of the process for its scale up.

  • Analysis of the isothermal condition in drying of acai berry residues for biomass application
    Biomass Bioenergy (IF 3.537) Pub Date : 2020-01-07
    Gabriele A. Nagata; Bernardo A. Souto; Maisa T.B. Perazzini; Hugo Perazzini

    Solid waste from acai berry (Euterpe oleracea Mart.) processing plants has gained attraction as biomass with great source of thermal energy. To increase the efficiency of thermochemical conversion process and improve its economic and environmental benefits, this bio-waste has to be submitted to drying, which is seen as a highly energy-intensive process. In this work, the coupling between heat and mass transfer established in convective drying of a spherical-shape biomass was investigated in order to obtain further information regarding to the isothermal approach. The experimental work consisted of the determination of temperature and moisture content of acai berry solid waste as function of the time at particle-level in a tunnel dryer. Experimental data was treated according to analytical solutions from heat and mass transfer diffusion theories, which provided the estimation of useful transport parameters to allow discussions of heat or mass transfer limiting and the approach to the isothermal condition. To facilitate this analysis, it was proposed a parameter called dimensionless penetration time. The experimental results showed that the temperature of the solid rapidly reached a stationary value closed to that for the gas, while the equilibrium moisture content took a longer time to be attained. In accordance to these findings, it was shown that heat and mass transfer phenomena are not strongly coupled for the reason that the dimensionless penetration time was much less than unity, indicating that the drying process is limited by moisture diffusion. Analysis of heat and mass transfer efficiencies was reported to strengthen such results.

  • Fertigation of Arundo donax L. with different nitrogen rates for biomass production
    Biomass Bioenergy (IF 3.537) Pub Date : 2020-01-07
    J. Cano-Ruiz; M. Sanz; M.D. Curt; A. Plaza; M.C. Lobo; P.V. Mauri

    Arundo donax L. has been recognized as a promising biomass crop for bioenergy and biobased applications. Previous nitrogen fertilization studies of this crop were based on conventional fertilizer application (broadcast). Fertigation is considered an efficient strategy to reduce nutrient loss in irrigated crops. The objective of this study was to investigate the effect of nitrogen fertigation on A.donax grown in low fertility soil, under a continental Mediterranean climate. Three levels of nitrogen supply (N) were studied: 0 N (0 kg ha−1 year−1), 60 N (60 kg ha−1 year−1); and 120 N (120 kg ha−1 year−1). Biometric parameters, leaf chlorophyll content, leaf weight percentage, biomass production and biomass quality as well as soil macronutrient concentration were evaluated. Nitrogen use efficiency and energy yield increase due to fertilization were also determined. Compared with unfertilized plants, fertigation increased plant height, basal diameter of stem, chlorophyll content, biomass production and fiber composition. However, the increase in N rate from 60 to 120 kg ha−1 year−1did not affect biomass yield. Energy increase due to N fertigation and nitrogen use efficiency led to the recommendation of using a fertigation N rate of 60 kg ha−1 for the A.donax cultivation in these experimental conditions.

  • Optimization of an organosolv method using glycerol with iron catalysts for the pretreatment of water hyacinth
    Biomass Bioenergy (IF 3.537) Pub Date : 2020-01-07
    Joselaine Carvalho Santana; Ana Karla Souza Abud; Alberto Wisniewski Junior; Sandro Navickiene; Luciane Pimenta Cruz Romão
  • Biogas optimisation processes and effluent quality: A review
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-12-23
    Abdul-Aziz Issah; Telesphore Kabera; Francis Kemausuor

    Since the first use of anaerobic digestion technology to generate biogas in 1895 to power street lights in Britain and also as a Municipal Solid Waste Management technique in the US in 1939, significant advances have been developed to optimise the process in a sustainable manner. In practice, optimising anaerobic digesters to increase biogas production dependent on a balanced pH (neutral), tolerable volatile fatty acids and alkalinity levels by anaerobic bacteria. Others include maintaining suitable temperature regime, providing suitable organic loading rate to prevent noxious conditions, well-balanced carbon to nitrogen ratio to limit ammonia build-up and appropriate choice of substrates. In terms of biomass, lignocellulose substrates constitute the most abundant bio-resource. This resource however requires modification of the chemistry of the structure to improve its biodegradation, biogas production and effluent quality. There have been attempts by most researchers to improve lignocellulose biomass utilization in anaerobic digesters through delignification to prevent non-productive binding of bacteria as well as reduce the crystalline in cellulose with the aim of making the holocellulose fractions bioavailable. However, none of the techniques so far applied for the purpose of optimising biogas production has attained the maximum theoretical biogas yield of 120,000–650,000 L t−1. Techniques frequently applied include among others; pretreatment (chemical, biological, physical or their combinations), co-digestion, application of inoculum or bio-augmentation, and supplementing anaerobic digesters with micronutrients and nanoparticles. This review thus highlights research findings from authors in relation to factors influencing effective degradation of lignin based biomass in other to ascertain the best possible strategies to scale up the process.

  • Approaches to investigate the role of chelation in the corrosivity of biomass-derived oils
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-12-19
    Raynella M. Connatser; Matthew G. Frith; Jiheon Jun; Samuel A. Lewis; Michael P. Brady; James R. Keiser

    The need to provide the U.S. market with a renewable liquid fuel energy source from a non-food feedstock stream has gained considerable traction due to benefits such as improved energy efficiency, reduced environmental impacts, and enhanced national security. Practical achievement of these goals via biomass and bio-waste utilization involves production of liquid intermediates containing corrosive, reactive species like carboxylic acids, ketones, aldehydes, and hydroxyaldehydes. Such mixtures challenge materials of containment, processing, and transport. It is widely recognized that the smaller organic acids, such as acetic and formic, are corrosive and can remove protective surface oxides on alloys used in bio-oil processing infrastructure, and ketones can swell sealing polymers. However, literature shows, and findings herein confirm, larger carboxylic acids and bidentate alcohols are present. This highlights the potential for synergistic, detrimental effects of constituents in bio-oil corrosion, including direct reactivity of small acids compounded with the possibility of mobilization of protective metal oxide layers via chelation by larger acids and oxygenates. The question of whether species beyond small acids can significantly contribute to corrosion requires analytical approaches previously not applied to bio-oil corrosion studies and certainly not previously applied corroboratively. This work introduces a combination of optical, mass spectral, and electrochemical impedance spectroscopies with an incubation approach to study metal mobilization, to facilitate elucidating chelation's role in bio-oil corrosive pathways. To enable systematic study of these oxygenates' material compatibility individually and in combination, a model matrix of bio-oil constituents was also developed based on identification of key components of real bio-oils.

  • Methanation potential: Suitable catalyst and optimized process conditions for upgrading biogas to reach gas grid requirements
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-12-19
    Rajeev Reddy Boggula; Dennis Fischer; René Casaretto; Jens Born
  • Synthesis of Ni–Mo–N catalysts for removing oxygen from acetophenone
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-12-18
    Chao Wang; Zhengke Li; Kui Wu; Jiajun Liu; Xiaofeng Yang; Xiangjin Kong; Yanping Huang; Weiyan Wang; Yunquan Yang
  • The development of trade of biomass in Spain: A raw material equivalent approach
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-12-19
    Mercedes Rodríguez; José A. Camacho

    Biomass is a key element within the Europe's Bioeconomy Strategy. This paper aims at contributing to a better knowledge of the evolution and current state of biomass trade in Spain by adopting a raw material equivalent approach. Instead of measuring trade flows in actual physical quantities, this approach expresses international trade flows in terms of the raw material needed to produce the traded products. The results obtained show that while raw material input of biomass increased by 3560 thousand tonnes over the period 2008–2016, raw material consumption decreased by 15,086 thousand tonnes. This is explained by the different pace of growth registered by raw material equivalent of exports and of imports: while raw material equivalent of exports rose from 49,485 thousand tonnes in 2008 to 68,131 thousand tonnes in 2016 recording a double digit growth of 38%, the increase in raw material equivalent of imports was considerably lower: from 64,560 thousand tonnes to 66,106 thousand tonnes, an increase of 2%. By categories, biomass from agriculture was the main driver of overall trade of biomass. Two groupings deserve special mention: fodder crops, which accounted for one quarter of raw material equivalent of exports, and cereals, which represented almost one third of raw material equivalent of imports in 2016.

  • Biofuel production potential from wastewater in India by integrating anaerobic membrane reactor with algal photobioreactor
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-12-19
    Saroj Sundar Baral; Davide Dionisi; Dileep Maarisetty; Akash Gandhi; Ankit Kothari; Gourav Gupta; Parag Jain

    A critical analysis of the novel sewage treatment concept of anaerobic digestion followed by CO2 capture by microalgae has been carried out, with particular reference to India. The anaerobic process would convert the sewage COD into methane and CO2, the latter being converted into microalgae in a photobioreactor process, using sunlight as an energy source. The microalgae can be used to produce biofuels, co-fired with high yielding fuels (like coke) or just recycled back into the anaerobic digestion cycle as a substrate for methane production. Overall, this process would allow, at least in principle, the conversion of all the carbon in the municipal wastewaters into fuels. This study reports data on municipal wastewater generation and treatment facilities across the globe. The focus is then given to sewage generation and treatment in Indian cities, classified into metropolitan, Class-I and Class-II cities. Aerobic and anaerobic digestion processes for sewage treatment are then compared with a discussion on the advantages of the anaerobic membrane bioreactor (AnMBR). The advantages and limitations of photobioreactors for microalgae growth are discussed. Mass balances are then carried out with reference to sewage flows and concentrations in India, and the potential energy generation from the process is estimated. Overall, the complete process is envisaged to produce about 1.69 × 108 kWhd−1 of energy from biogas and microalgae. This has the potential to replace 3% of the recent total petroleum product consumption in India. The study goes towards “zero discharge” of waste to the environment, thus representing a promising sustainable development.

  • Effects of enzyme addition on biogas and methane yields in the batch anaerobic digestion of agricultural waste (silage, straw, and animal manure)
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-12-12
    Tobias Weide; Carolina Duque Baquero; Marion Schomaker; Elmar Brügging; Christof Wetter
  • Exoproteome profile reveals thermophilic fungus Crassicarpon thermophilum (strain 6GKB; syn. Corynascus thermophilus) as a rich source of cellobiose dehydrogenase for enhanced saccharification of bagasse
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-12-09
    Rohit Rai, Neha Basotra, Baljit Kaur, Macros Di Falco, Adrian Tsang, B.S. Chadha

    LC-MS/MS based profiling revealed thermophilic fungus Crassicarpon thermophilum strain 6GKB as a prolific producer of cellobiose dehydrogenase (CDH; AA8). CDH is an important component of the newly discovered oxidative system comprising CDH and lytic polysaccharide monooxygenases (LPMO), known for its ability to enhance degradation of lignocellulosics. CDH from C. thermophilum was purified using culture extract harvested after 7 days of culture on cellulose, wheat bran and rice straw (CWR) based medium by employing hydrophobic interaction chromatography in tandem with ion exchange chromatography. SDS-PAGE confirmed enzyme purity and presence of a single protein band at a molecular weight of 84 kDa. The purified CDH (ctCDH) was found to be stable under optimal temperature (50 °C) and pH (5.0) conditions with t1/2 of 360 min. The Kinetic characterization of ctCDH showed similar affinity (4.5 and 4.0 mM) and specificity (2.6 × 105 and 2.5 × 105 mM−1 s−1) of the enzyme towards cellobiose and lactose, respectively. In addition, coalescence of spectral and electron acceptor studies confirmed ctCDH to be a flavocytochrome. Through this study, we further demonstrate the potential of ctCDH alone and in combination with LPMO to enhance the efficiency of commercial cellulase Cellic CTec2 to hydrolyze alkali and acid treated bagasse by upto 1.35 folds. Conclusively, ctCDH reported in this study is a potent enzyme that could be utilized for numerous biotechnological applications involving enzymatic degradation of lignocellulosic biomass.

  • A comparison of harvesting and drying methodologies on fatty acids composition of the green microalga Scenedesmus obliquus
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-12-09
    Carlos Yure Barbosa de Oliveira, Thayna Lye Viegas, Rafael Garcia Lopes, Herculano Cella, Rafael Silva Menezes, Aline Terra Soares, Nelson Roberto Antoniosi Filho, Roberto Bianchini Derner

    Harvesting and drying processes are still obstacles in the microalgae production chain. In this study, a combination of different harvesting and drying methods for Scenedesmus obliquus was proposed. S. obliquus was cultivated in a pond raceway for 15 days until reaching stationary phase. The culture was separated by different harvesting methods (centrifugation and flocculation) and drying methods (freezing, freeze-drying and oven drying), each combination in triplicate. Flocculation did not influence FAME yield of S. obliquus, except when the biomass was dried in an oven. The biomass that was only frozen had the lowest FAME content due to the presence of reactive water in the biomass. In contrast, frozen biomass had higher content of saturated and monosaturated fatty acids; freeze-drying or oven drying caused an enrichment of the polyunsaturated fatty acids content. In conclusion, if the biomass will be used to extract polyunsaturated fatty acids, freeze-drying would be more appropriate. On the other hand, if the purpose of the biomass is to produce biodiesel, the best process would be to just freeze the biomass.

  • Advanced biofuel production and road to commercialization: An insight into bioconversion potential of Rhodosporidium sp.
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-12-09
    Rahul Saini, Krishnamoorthy Hegde, Satinder Kaur Brar, Pierre Vezina

    In recent years, Rhodosporidium sp. has received significant interest in advanced biofuel production due to its ability to accumulate more than 60% lipid of their total dry cell weight. Moreover, it can thrive on a wide variety of substrates, has high inhibitor tolerance, and faster growth rate. Despite these advantages and based on current technological advancement, the true potential of Rhodosporidium sp. as a biofuel producer and its commercialization feasibility is still questionable. Thus, this review aims to illustrate the problems that are associated with Rhodosporidium sp. in the field of biofuel production. Apart from this, information regarding factors affecting lipid accumulation, and the role of genetic and metabolic engineering is presented. Additionally, the economic outlook of microbial lipid-derived using lignocellulosic biomass has also been reviewed. Drop-in oil production and its commercialization needs are discussed to bring Rhodosporidium sp. into the limelight and, eventually, to revolutionize the entire biofuel industry.

  • Application of bio-based alkali to induce flocculation of microalgae biomass
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-12-07
    Sheriff Olalekan Ajala, Matthew L. Alexander
  • Forecasting Turkey's cattle and sheep manure based biomethane potentials till 2026
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-12-07
    Mehmet Melikoglu, Zeynep Kubra Menekse

    In this study, Turkey's cattle and sheep manure based biomethane potentials are forecasted till 2026. Novel to this study, semi-empirical models based on per capita meat consumption and milk production are used to forecast Turkey's cattle and sheep population. It is estimated that Turkey's cattle and sheep population in 2026 could reach up to 18.7 and 39.2 million, respectively. At these population levels, Turkey's cattle and sheep manure based biomethane generation could reach up to 1.99 billion m3 and 0.15 billion m3, respectively. This is equal to a total of nearly 2.14 billion m3 of biomethane in 2026. This amount of biomethane could provide nearly 6,600 GWh of electricity or supply nearly 2.9% of Turkey's natural gas demand in 2026.

  • Mutual effect of sodium and magnesium on the cultivation of microalgae Auxenochlorella protothecoides
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-12-07
    Ece Polat, Ebubekir Yüksel, Mahmut Altınbaş

    Microalgae are a sustainable energy source because of their lipid storage capacity. However, the cultivation of microalgae requires optimization to produce a high biomass and lipid content. Stressing the cell is a common approach that is applied to increase the lipid content of the algae. Within this context, sodium chloride (NaCl) stress and magnesium (Mg2+) limitations were applied individually and mutually to understand their potential effects on biomass, lipid quantity, and the fatty acid methyl esters (FAME) profile of Auxenochlorella protothecoides. Saturated fatty acid (SFA) contents as high as 43.9% were obtained at 0 mg L−1 Mg2+ with 5 g L−1 NaCl. The highest linoleic acid content (35.2%) was obtained at 0.3 mg L−1 Mg2+ with 2.5 g L−1 NaCl. However, the highest biomass was achieved at 18.5 mg L−1 Mg2+ with 5.0 g L−1 NaCl according to surface response methodology. These optimization data could be useful for producing a feasible and sustainable biodiesel production strategy with high biomass and lipid productivity.

  • Are global ethanol markets a ‘one great pool’?
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-12-05
    Anupam Dutta

    The main objective of this empirical work is to test whether the global ethanol markets move together. To serve this purpose, prices of the US and Brazilian ethanol sectors have been analyzed. Employing the asymmetric multivariate GARCH model, we document significant price and volatility spillover effects between the ethanol markets under study. Such findings indicate that world ethanol markets move together and they are not regionalized. These results have important implications. For example, given that ethanol markets are codependent, information flow across ethanol markets could guide policymaking and the formulation of hedging strategies for contagion risk prevention during ethanol market downturns. In addition, this type of information on ethanol markets is also crucial for investors to maintain well-diversified portfolios, and for opening (closing) investment positions.

  • An efficient and reliable method for determining the angle of repose of biomass by using 3D scan
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-12-03
    Y. Tan, J. Fottner, S. Kessler

    This paper proposed a novel methodology to determine the angle of repose (AoR) of various biomass materials. Because of irregular shape and varying particle size distribution, slopes of biomass materials are uneven frequently and the two traditional measurement methods of AoR are therefore less applicable and reliable. In general, only partial slopes of heap surface are selected to measure AoR, although a representable slope is barely defined in standard methods. In this case, the subjective selection of slopes may result in significant deviations. Hence, we presented an efficient and reliable measurement method of AoR. In addition to the traditional bottomless cylinder test, the new technology, 3D scan, was used to digitize the generated bulk heap. Then, two data processing methods were introduced to deal with different heap forms: direct calculation based on the linear least-squares regression with regard to the whole heap surface and the pre-selection of planes for excluding outliners caused by particle bridging. For the purpose of simplifying the process, a self-developed graphic user interface (GUI) was used to analyze four kinds of biomass fuels, namely, olive stone, almond shells, forest residues and willow chips, and verify the proposed method. Both methods significantly decreased the deviations of results without increasing operating time and cost.

  • Pyrolysis chars and physically activated carbons prepared from buckwheat husks for catalytic purification of syngas
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-11-30
    Jenny Pena, Audrey Villot, Claire Gerente

    This paper investigates the impact of the oxidizing agent used in the physical activation of pyrolysis chars on activated carbons (AC), and their efficiency in tar cracking. The materials are produced from buckwheat husk, which is a French local biomass. Slow pyrolysis was chosen to favor the production of raw chars. Activated chars were then prepared by physical activation under steam or CO2. The materials produced were physically and chemically characterized before being implemented in a fixed bed. The efficiency of materials in removing tar from syngas was studied, and ethylbenzene (EB) was chosen as the tar surrogate. The purification efficiency of the chars and AC was deduced from the EB conversion profiles in comparison with thermal cracking. The nature of the oxidizing agent impacted the porosity and mineral composition of the AC produced: CO2 activation produced ACs with more carbon and less ash content. This is because the reduction of carbon with carbon dioxide presents a kinetic between 2 and 5 times slower than that conducted in the presence of steam. CO2 activation also resulted in a higher relative microporosity (89%) than steam activation (61%), which itself gives a higher surface area. Pyrolysis char did not generate any interest for EB catalytic cracking, whereas ACs demonstrated higher performances. This is due to their higher level of porosity and higher ash content. BH–H2O, which presents higher porosity, produced a better catalytic effect and was more resistant to deactivation.

  • A review on the catalytic hydrodeoxygenation of lignin-derived phenolic compounds and the conversion of raw lignin to hydrocarbon liquid fuels
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-11-29
    Riyang Shu, Rongxuan Li, Biqin Lin, Chao Wang, Zhengdong Cheng, Ying Chen
  • Effects of operating parameters on algae Chlorella vulgaris biomass harvesting and lipid extraction using metal sulfates as flocculants
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-11-28
    Liandong Zhu, Tianyi Hu, Shuangxi Li, Yohanes K. Nugroho, Baishan Li, Jun Cao, Pau-Loke Show, Erkki Hiltunen

    Flocculation is regarded as an effective, convenient and promising means for microalgal harvesting of microalgal biomass. In this study three types of metal sulfates (aluminum sulfate, aluminum potassium sulfate and ferric sulfate) were applied as flocculants to harvest microalgae Chlorella vulgaris biomass. The optimal operating parameters such as dosage, rotation speed, flocculation time and sedimentation time during microalgal biomass harvesting were determined, and the effects of metal sulfate application as flocculants on lipid extraction were investigated. The results showed that the optimal dosage for the three flocculants to harvest microalgal biomass was identically 2.5 g L−1, and the optimal rotation speeds for coagulation and flocculation were 150 and 25 rpm, respectively, while the flocculation time of 10 min was found to be appropriate. The findings also suggested that metal residuals in flocculated biomass would affect lipid extraction, resulting in 5.9%, 4.4% and 3.3% reduction of lipid contents for aluminum sulfate, aluminum potassium sulfate and ferrous sulfate, respectively. The contribution of this study lies in the provision of the optimal operating parameters during the microalgal biomass flocculation, thus potentially offering the technical guidance for the harvesting of microalgal biomass using metal sulfates as flocculants in practice.

  • Optimization of the energy consumption in activated sludge process using deep learning selective modeling
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-11-26
    Rafik Oulebsir, Abdelouahab Lefkir, Abdelhamid Safri, Abdelmalek Bermad

    This paper presents a method using an artificial neural network for creating an optimal model of energy consumption in wastewater treatment plant (WWTP) using activated sludge process. The advantage of this method is the use data usually measured in most of WWTP to optimize the energy consumption of the biological process. This method consists of selecting the data that represent the best energy consumption using different performance criteria then use this data to train a deep neural network. The procedure of selection is divided into two parts, in the first selection we selected the data that respect the environmental standards, and in the second part we selected the data with optimal energy consumption using different pollution indicators, and this data was used to train a deep neural network, finally the best model was used to estimate the energy savings on the data not selected. The model showed good results with a coefficient of determination that varies between 90% and 92% in training period and 74%–82% in testing period, the application of the best model on the data not selected showed a gain in energy for the most of the data.

  • Optimization of slow pyrolysis process parameters using a fixed bed reactor for biochar yield from rice husk
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-11-22
    Fábio Roberto Vieira, Carlos M. Romero Luna, Gretta L.A.F. Arce, Ivonete Ávila

    A fixed bed reactor has been used to assess the influence of slow pyrolysis process parameters on biochar yield from rice husk. Taguchi's method (L9) was used for such a purpose, which four parameters varied according to three different levels: heating rate (β) of 5, 10 and 20 °C/min; temperature (T) of 300, 400, and 500 °C; residence time (t) of 3600, 5400 and 7200 s; rice husk mass (m) of 125, 250, and 500 g. ANOVA were utilized to verify the statistical significance of process parameters. Different physical-chemistry techniques have been performed to assess the energy potential of processing rice husk through thermochemical processes. The results showed that the highest biochar yield (37.71 %wt) was achieved through the following experimental conditions: 500 g of biomass, β = 20 °C/min, T = 300 °C, and t = 5400 s. However, the highest heating value (HHV = 23.41 MJ/kg) was obtained by using 125 g of biomass, β = 10 °C/min, T = 500 °C, and t = 5400 s. However, optimal conditions for higher fixed carbon content (60.10 %wt) were 500 g of biomass, β = 5 °C/min, T = 500 °C, and t = 7200 s. It was 49.05% higher than HHV found for raw rice husk. ANOVA results have revealed that temperature is the most significant parameter for the slow pyrolysis process. Furthermore, Taguchi's method was applied to define the levels of experimental conditions and optimize the process. Energy ratio assessment yielded values ranging between 0.38 and 1.77, which indicates that it is technically feasible to obtain energy gains through the slow pyrolysis of rice husk.

  • Application of response surface methodology in catalytic co-gasification of palm wastes for bioenergy conversion using mineral catalysts
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-11-20
    Muddasser Inayat, Shaharin A. Sulaiman, Muhammad Shahbaz, Bilawal A. Bhayo
  • Current advances in on-site cellulase production and application on lignocellulosic biomass conversion to biofuels: A review
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-11-19
    Joyce Gueiros Wanderley Siqueira, Cristine Rodrigues, Luciana Porto de Souza Vandenberghe, Adenise Lorenci Woiciechowski, Carlos Ricardo Soccol

    The potential of lignocellulosic feedstock has been widely studied, mainly for biofuels production, which usually requires an enzymatic step on the process. Cellulolytic enzymes have been studied as input for bioconversion and as a product from lignocellulose fermentation. The integration of these two perspectives may lead to an economically viable approach for second generation biofuels production, which is nowadays difficult due to high cost of commercial cellulase. Conversely, enzyme production by fermentation of lignocellulosic substrates is inexpensive and the hydrolytic activity of enzymes produced on these substrates, which are to be hydrolyzed, may be better than those enzymes produced on other materials, such as cellulose. Many studies have defined the ideal conditions for cellulase production and saccharification processes separately. In contrast, few reports have developed a unique and integrated process, based on the same feedstock. This review is focused on current advances and innovation in on-site cellulolytic enzymes production using plant biomass, and application of the enzymes in lignocellulose conversion to fermentable sugars for biofuel production.

  • Pretreatment with Trichoderma sp. AH enhances conversion and specificity of wheat straw in supercritical methanolysis
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-06-12
    Quan-Xi Zheng, Xian-Yong Wei, Xin Xu, Liang Xin, Li Guo, Zhi-Min Zong, Jian-Qiang Hu

    Supercritical methanolysis (SCM) of pretreated wheat straw (WS) with the white-rot fungus Trichoderma sp. AH was investigated. Structural change of pretreated WS was examined by Fourier transform infrared spectrometric analysis and chemical analysis as well as observation with a scanning electron microscope. The optimal pretreatment (PT) time of WS was 5 days of incubation, obtaining the maximum methanol-soluble portion (MSP) yield of 38.3% at 260 °C, compared with MSP yield of 24.6% of raw WS. According to the detailed compositional analysis of MSPs from SCM of raw and pretreated WS, after 5 days of incubation, PT with Trichoderma sp. AH enhanced conversion, specificity and content of esters significantly. Especially, the relative contents of methyl palmitate, methyl (9Z,12Z)-octadeca-9,12-dienoate, and methyl (E)-octadec-11-enoate in MSPs were increased dramatically. Therefore, the study brings out the potential of PT with Trichoderma sp. AH for facilitating conversion and specificity of biomass in liquefaction.

  • The effect of harvest date and the chemical characteristics of biomass from Molinia meadows on methane yield
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-11-05
    Mateusz Meserszmit, Mariusz Chrabąszcz, Monika Chylińska, Monika Szymańska-Chargot, Adriana Trojanowska-Olichwer, Zygmunt Kącki

    Molinia meadows are seminatural habitats of Natura 2000, and their continued existence is heavily dependent on human activities. The aim of the present study was to determine the effect of the harvest time of meadow biomass originating from Molinia meadows on the methane yield. After 35 days of conducting batch digestion tests, the average methane yield was found to be slightly different over the course of four biomass harvest dates: at the end of May, 221 ± 8 NL CH4 kg−1 VS; at the beginning of July, 211 ± 21 NL CH4 kg−1 VS; at the end of July, 200 ± 8 NL CH4 kg−1 VS and on September 1, 197 ± 2 NL CH4 kg−1 VS. During the initial stages of batch fermentation, a higher methane yield was obtained from the biomass harvested at the end of May. This biomass was characterised by higher contents of N, P and K, as well as a lower C:N ratio and reduced Ca and cellulose content. Relative to the content of elements and cellulose as well as the C:N ratio observed, significant correlations were found for methane yields from biomass obtained between the fourth and eighth days of batch digestion. It was determined that the average methane yield on a per hectare basis for the harvested biomass differed depending on the harvest date under investigation. The use of biomass from Molinia meadows for biogas production has the potential to become an important factor in the environmental protection of this type of habitat.

  • Microbubble-enhanced dielectric barrier discharge pretreatment of microcrystalline cellulose.
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-04-23
    Alexander Wright,Adam Marsh,Federica Ricciotti,Alex Shaw,Felipe Iza,Richard Holdich,Hemaka Bandulasena

    Cellulose recalcitrance is one of the major barriers in converting renewable biomass to biofuels or useful chemicals. A pretreatment reactor that forms a dielectric barrier discharge plasma at the gas-liquid interface of the microbubbles has been developed and tested to pretreat α-cellulose. Modulation of the plasma discharge provided control over the mixture of species generated, and the reactive oxygen species (mainly ozone) were found to be more effective in breaking-up the cellulose structure compared to that of the reactive nitrogen species. The effectiveness of pretreatment under different conditions was determined by measuring both the solubility of treated samples in sodium hydroxide and conversion of cellulose to glucose via enzymatic hydrolysis. Solutions pretreated under pH 3 buffer solutions achieved the best result raising the solubility from 17% to 70% and improving the glucose conversion from 24% to 51%. Under the best conditions, plasma-microbubble treatment caused pronounced crevices on the cellulose surface enhancing access to the reactive species for further breakdown of the structure and to enzymes for saccharification.

  • Integrating social and value dimensions into sustainability assessment of lignocellulosic biofuels.
    Biomass Bioenergy (IF 3.537) Pub Date : 2015-12-15
    Sujatha Raman,Alison Mohr,Richard Helliwell,Barbara Ribeiro,Orla Shortall,Robert Smith,Kate Millar

    The paper clarifies the social and value dimensions for integrated sustainability assessments of lignocellulosic biofuels. We develop a responsible innovation approach, looking at technology impacts and implementation challenges, assumptions and value conflicts influencing how impacts are identified and assessed, and different visions for future development. We identify three distinct value-based visions. From a techno-economic perspective, lignocellulosic biofuels can contribute to energy security with improved GHG implications and fewer sustainability problems than fossil fuels and first-generation biofuels, especially when biomass is domestically sourced. From socio-economic and cultural-economic perspectives, there are concerns about the capacity to support UK-sourced feedstocks in a global agri-economy, difficulties monitoring large-scale supply chains and their potential for distributing impacts unfairly, and tensions between domestic sourcing and established legacies of farming. To respond to these concerns, we identify the potential for moving away from a one-size-fits-all biofuel/biorefinery model to regionally-tailored bioenergy configurations that might lower large-scale uses of land for meat, reduce monocultures and fossil-energy needs of farming and diversify business models. These configurations could explore ways of reconciling some conflicts between food, fuel and feed (by mixing feed crops with lignocellulosic material for fuel, combining livestock grazing with energy crops, or using crops such as miscanthus to manage land that is no longer arable); different bioenergy applications (with on-farm use of feedstocks for heat and power and for commercial biofuel production); and climate change objectives and pressures on farming. Findings are based on stakeholder interviews, literature synthesis and discussions with an expert advisory group.

  • The changing nature of life cycle assessment.
    Biomass Bioenergy (IF 3.537) Pub Date : 2015-12-15
    Marcelle C McManus,Caroline M Taylor

    LCA has evolved from its origins in energy analysis in the 1960s and 70s into a wide ranging tool used to determine impacts of products or systems over several environmental and resource issues. The approach has become more prevalent in research, industry and policy. Its use continues to expand as it seeks to encompass impacts as diverse as resource accounting and social well being. Carbon policy for bioenergy has driven many of these changes. Enabling assessment of complex issues over a life cycle basis is beneficial, but the process is sometimes difficult. LCA's use in framing is increasingly complex and more uncertain, and in some cases, irreconcilable. The charged environment surrounding biofuels and bioenergy exacerbates all of these. Reaching its full potential to help guide difficult policy discussions and emerging research involves successfully managing LCA's transition from attributional to consequential and from retrospective to prospective. This paper examines LCA's on-going evolution and its use within bioenergy deployment. The management of methodological growth in the context of the unique challenges associated with bioenergy and biofuels is explored. Changes seen in bioenergy LCA will bleed into other LCA arenas, especially where it is important that a sustainable solution is chosen.

  • High yielding biomass genotypes of willow (Salix spp.) show differences in below ground biomass allocation.
    Biomass Bioenergy (IF 3.537) Pub Date : 2015-09-05
    Jennifer Cunniff,Sarah J Purdy,Tim J P Barraclough,March Castle,Anne L Maddison,Laurence E Jones,Ian F Shield,Andrew S Gregory,Angela Karp

    Willows (Salix spp.) grown as short rotation coppice (SRC) are viewed as a sustainable source of biomass with a positive greenhouse gas (GHG) balance due to their potential to fix and accumulate carbon (C) below ground. However, exploiting this potential has been limited by the paucity of data available on below ground biomass allocation and the extent to which it varies between genotypes. Furthermore, it is likely that allocation can be altered considerably by environment. To investigate the role of genotype and environment on allocation, four willow genotypes were grown at two replicated field sites in southeast England and west Wales, UK. Above and below ground biomass was intensively measured over two two-year rotations. Significant genotypic differences in biomass allocation were identified, with below ground allocation differing by up to 10% between genotypes. Importantly, the genotype with the highest below ground biomass also had the highest above ground yield. Furthermore, leaf area was found to be a good predictor of below ground biomass. Growth environment significantly impacted allocation; the willow genotypes grown in west Wales had up to 94% more biomass below ground by the end of the second rotation. A single investigation into fine roots showed the same pattern with double the volume of fine roots present. This greater below ground allocation may be attributed primarily to higher wind speeds, plus differences in humidity and soil characteristics. These results demonstrate that the capacity exists to breed plants with both high yields and high potential for C accumulation.

  • Development of an estimation model for the evaluation of the energy requirement of dilute acid pretreatments of biomass.
    Biomass Bioenergy (IF 3.537) Pub Date : 2015-06-26
    Oluwakemi A T Mafe,Scott M Davies,John Hancock,Chenyu Du

    This study aims to develop a mathematical model to evaluate the energy required by pretreatment processes used in the production of second generation ethanol. A dilute acid pretreatment process reported by National Renewable Energy Laboratory (NREL) was selected as an example for the model's development. The energy demand of the pretreatment process was evaluated by considering the change of internal energy of the substances, the reaction energy, the heat lost and the work done to/by the system based on a number of simplifying assumptions. Sensitivity analyses were performed on the solid loading rate, temperature, acid concentration and water evaporation rate. The results from the sensitivity analyses established that the solids loading rate had the most significant impact on the energy demand. The model was then verified with data from the NREL benchmark process. Application of this model on other dilute acid pretreatment processes reported in the literature illustrated that although similar sugar yields were reported by several studies, the energy required by the different pretreatments varied significantly.

  • Emission and Size Distribution of Particle-bound Polycyclic Aromatic Hydrocarbons from Residential Wood Combustion.
    Biomass Bioenergy (IF 3.537) Pub Date : 2015-02-14
    Guofeng Shen,Siye Wei,Yanyan Zhang,Bin Wang,Rong Wang,Huizhong Shen,Wei Li,Ye Huang,Yuanchen Chen,Han Chen,Shu Tao

    Emissions and size distributions of 28 particle-bound polycyclic aromatic hydrocarbons (PAHs) from residential combustion of 19 fuels in a domestic cooking stove in rural China were studied. Measured emission factors of total PAHs were 1.79±1.55, 12.1±9.1, and 5.36±4.46 mg/kg for fuel wood, brushwood, and bamboo, respectively. Approximate 86.7, 65.0, and 79.7% of the PAHs were associated with fine particulate matter with size less than 2.1 µm for these three types of fuels. Statistically significant difference in emission factors and size distributions of particle-bound PAHs between fuel wood and brushwood was observed, with the former had lower emission factors but more PAHs in finer PM. Mass fraction of the fine particles associated PAHs was found to be positively correlated with fuel density and moisture, and negatively correlated with combustion efficiency. Low and high molecular weight PAHs segregated into the coarse and fine PM, respectively. The high accumulation tendency of the PAHs from residential wood combustion in fine particles implies strong adverse health impact.

  • Global bioenergy potentials from agricultural land in 2050: Sensitivity to climate change, diets and yields.
    Biomass Bioenergy (IF 3.537) Pub Date : 2012-01-03
    Helmut Haberl,Karl-Heinz Erb,Fridolin Krausmann,Alberte Bondeau,Christian Lauk,Christoph Müller,Christoph Plutzar,Julia K Steinberger

    There is a growing recognition that the interrelations between agriculture, food, bioenergy, and climate change have to be better understood in order to derive more realistic estimates of future bioenergy potentials. This article estimates global bioenergy potentials in the year 2050, following a "food first" approach. It presents integrated food, livestock, agriculture, and bioenergy scenarios for the year 2050 based on a consistent representation of FAO projections of future agricultural development in a global biomass balance model. The model discerns 11 regions, 10 crop aggregates, 2 livestock aggregates, and 10 food aggregates. It incorporates detailed accounts of land use, global net primary production (NPP) and its human appropriation as well as socioeconomic biomass flow balances for the year 2000 that are modified according to a set of scenario assumptions to derive the biomass potential for 2050. We calculate the amount of biomass required to feed humans and livestock, considering losses between biomass supply and provision of final products. Based on this biomass balance as well as on global land-use data, we evaluate the potential to grow bioenergy crops and estimate the residue potentials from cropland (forestry is outside the scope of this study). We assess the sensitivity of the biomass potential to assumptions on diets, agricultural yields, cropland expansion and climate change. We use the dynamic global vegetation model LPJmL to evaluate possible impacts of changes in temperature, precipitation, and elevated CO(2) on agricultural yields. We find that the gross (primary) bioenergy potential ranges from 64 to 161 EJ y(-1), depending on climate impact, yields and diet, while the dependency on cropland expansion is weak. We conclude that food requirements for a growing world population, in particular feed required for livestock, strongly influence bioenergy potentials, and that integrated approaches are needed to optimize food and bioenergy supply.

  • Dry matter losses and quality changes during short rotation coppice willow storage in chip or rod form.
    Biomass Bioenergy (IF 3.537) Pub Date : 2018-05-05
    Carly Whittaker,Nicola E Yates,Stephen J Powers,Tom Misselbrook,Ian Shield

    This study compares dry matter losses and quality changes during the storage of SRC willow as chips and as rods. A wood chip stack consisting of approximately 74 tonnes of fresh biomass, or 31 tonnes dry matter (DM) was built after harvesting in the spring. Three weeks later, four smaller stacks of rods with an average weight of 0.8 tonnes, or 0.4 tonnes DM were built. During the course of the experiment temperature recorders placed in the stacks found that the wood chip pile reached 60 °C within 10 days of construction, but the piles of rods remained mostly at ambient temperatures. Dry matter losses were calculated by using pre-weighed independent samples within the stacks and by weighing the whole stack before and after storage. After 6 months the wood chip stack showed a DM loss of between 19.8 and 22.6%, and mean losses of 23.1% were measured from the 17 independent samples. In comparison, the rod stacks showed an average stack DM loss of between 0 and 9%, and between 1.4% and 10.6% loss from the independent samples. Analysis of the stored material suggests that storing willow in small piles of rods produces a higher quality fuel in terms of lower moisture and ash content; however, it has a higher fine content compared to storage in chip form. Therefore, according to the two storage methods tested here, there may be a compromise between maximising the net dry matter yield from SRC willow and the final fine content of the fuel.

  • Straw use and availability for second generation biofuels in England.
    Biomass Bioenergy (IF 3.537) Pub Date : 2013-08-01
    Neryssa J Glithero,Paul Wilson,Stephen J Ramsden

    Meeting EU targets for renewable transport fuels by 2020 will necessitate a large increase in bioenergy feedstocks. Although deployment of first generation biofuels has been the major response to meeting these targets they are subject to wide debate on their sustainability leading to the development of second generation technologies which use lignocellulosic feedstocks. Second generation biofuel can be subdivided into those from dedicated bioenergy crops (DESGB), e.g. miscanthus, or those from co-products (CPSGB) such as cereal straw. Potential supply of cereal straw as a feedstock for CPSGB's is uncertain in England due to the difficulty in obtaining data and the uncertainty in current estimates. An on-farm survey of 249 farms (Cereal, General Cropping and Mixed) in England was performed and linked with Farm Business Survey data to estimate current straw use and potential straw availability. No significant correlations between harvested grain and straw yields were found for wheat and oilseed rape and only a weak correlation was observed for barley. In England there is a potential cereal straw supply of 5.27 Mt from arable farm types; 3.82 Mt are currently used and 1.45 Mt currently chopped and incorporated. If currently chopped and incorporated cereal straw from arable farm types was converted into bioethanol, this could represent 1.5% of the UK petrol consumption by energy equivalence. The variations in regional straw yields (t ha-1) have a great effect on the England supply of straw and the potential amount of bioethanol that can be produced.

  • Temperature dataloggers as stove use monitors (SUMs): Field methods and signal analysis.
    Biomass Bioenergy (IF 3.537) Pub Date : 2012-12-01
    Ilse Ruiz-Mercado,Eduardo Canuz,Kirk R Smith

    We report the field methodology of a 32-month monitoring study with temperature dataloggers as Stove Use Monitors (SUMs) to quantify usage of biomass cookstoves in 80 households of rural Guatemala. The SUMs were deployed in two stoves types: a well-operating chimney cookstove and the traditional open-cookfire. We recorded a total of 31,112 days from all chimney cookstoves, with a 10% data loss rate. To count meals and determine daily use of the stoves we implemented a peak selection algorithm based on the instantaneous derivatives and the statistical long-term behavior of the stove and ambient temperature signals. Positive peaks with onset and decay slopes exceeding predefined thresholds were identified as "fueling events", the minimum unit of stove use. Adjacent fueling events detected within a fixed-time window were clustered in single "cooking events" or "meals". The observed means of the population usage were: 89.4% days in use from all cookstoves and days monitored, 2.44 meals per day and 2.98 fueling events. We found that at this study site a single temperature threshold from the annual distribution of daily ambient temperatures was sufficient to differentiate days of use with 0.97 sensitivity and 0.95 specificity compared to the peak selection algorithm. With adequate placement, standardized data collection protocols and careful data management the SUMs can provide objective stove-use data with resolution, accuracy and level of detail not possible before. The SUMs enable unobtrusive monitoring of stove-use behavior and its systematic evaluation with stove performance parameters of air pollution, fuel consumption and climate-altering emissions.

  • Quantitative metrics of stove adoption using Stove Use Monitors (SUMs).
    Biomass Bioenergy (IF 3.537) Pub Date : 2014-09-27
    Ilse Ruiz-Mercado,Eduardo Canuz,Joan L Walker,Kirk R Smith

    The sustained use of cookstoves that are introduced to reduce fuel use or air pollution needs to be objectively monitored to verify the sustainability of these benefits. Quantifying stove adoption requires affordable tools, scalable methods and validated metrics of usage. We quantified the longitudinal patterns of chimney-stove use of 80 households in rural Guatemala, monitored with Stove Use Monitors (SUMs) during 32 months. We counted daily meals and days in use at each monitoring period and defined metrics like the percent stove-days in use (the fraction of days in use from all stoves and days monitored). Using robust Poisson regressions we detected small seasonal variations in stove usage, with peaks in the warm-dry season at 92% stove-days (95%CI: 87%,97%) and 2.56 average daily meals (95%CI: 2.40,2.74). With respect to these values, the percent stove-days in use decreased by 3% and 4% during the warm-rainy and cold-dry periods respectively, and the daily meals by 5% and 12% respectively. Cookstove age and household size at baseline did not affect usage. Qualitative indicators of use from recall questionnaires were consistent with SUMs measurements, indicating stable sustained use and questionnaire accuracy. These results reflect optimum conditions for cookstove adoption and for monitoring in this project, which may not occur in disseminations undertaken elsewhere. The SUMs measurements suggests that 90% stove-days is a more realistic best-case for sustained use than the 100% often assumed. Half of sample reported continued use of open-cookfires, highlighting the critical need to verify reduction of open-fire practices in stove disseminations.

  • 'Energy landscapes': Meeting energy demands and human aspirations.
    Biomass Bioenergy (IF 3.537) Pub Date : 2013-08-01
    Thomas Blaschke,Markus Biberacher,Sabine Gadocha,Ingrid Schardinger

    Renewable energy will play a crucial role in the future society of the 21st century. The various renewable energy sources need to be balanced and their use carefully planned since they are characterized by high temporal and spatial variability that will pose challenges to maintaining a well balanced supply and to the stability of the grid. This article examines the ways that future 'energy landscapes' can be modelled in time and space. Biomass needs a great deal of space per unit of energy produced but it is an energy carrier that may be strategically useful in circumstances where other renewable energy carriers are likely to deliver less. A critical question considered in this article is whether a massive expansion in the use of biomass will allow us to construct future scenarios while repositioning the 'energy landscape' as an object of study. A second important issue is the utilization of heat from biomass energy plants. Biomass energy also has a larger spatial footprint than other carriers such as, for example, solar energy. This article seeks to provide a bridge between energy modelling and spatial planning while integrating research and techniques in energy modelling with Geographic Information Science. This encompasses GIS, remote sensing, spatial disaggregation techniques and geovisualization. Several case studies in Austria and Germany demonstrate a top-down methodology and some results while stepwise calculating potentials from theoretical to technically feasible potentials and setting the scene for the definition of economic potentials based on scenarios and assumptions.

  • Potential of genetically modified oilseed rape for biofuels in Austria: Land use patterns and coexistence constraints could decrease domestic feedstock production.
    Biomass Bioenergy (IF 3.537) Pub Date : 2013-03-01
    Dietmar Moser,Michael Eckerstorfer,Kathrin Pascher,Franz Essl,Klaus Peter Zulka

    Like other EU Member States, Austria will meet the substitution target of the EU European Renewable Energy Directive for transportation almost exclusively by first generation biofuels, primarily biodiesel from oilseed rape (OSR). Genetically modified (GM) plants have been promoted as a new option for biofuel production as they promise higher yield or higher quality feedstock. We tested implications of GM OSR application for biodiesel production in Austria by means of high resolution spatially explicit simulation of 140 different coexistence scenarios within six main OSR cropping regions in Austria (2400 km2). We identified structural land use characteristics such as field size, land use diversity, land holding patterns and the proportion of the target crop as the predominant factors which influence overall production of OSR in a coexistence scenario. Assuming isolation distances of 800 m and non-GM-OSR proportions of at least 10% resulted in a loss of area for cultivation of OSR in all study areas ranging from -4.5% to more than -25%, depending on the percentage of GM farmers and on the region. We could show that particularly the current primary OSR cropping regions are largely unsuitable for coexistence and would suffer from a net loss of OSR area even at isolation distances of 400 or 800 m. Coexistence constraints associated with application of GM OSR are likely to offset possible GM gains by substantially reducing farmland for OSR cultivation, thus contradicting the political aim to increase domestic OSR area to meet the combined demands of food, feed and biofuel production.

  • Techno-economic analysis of a liquid hot water pretreated switchgrass biorefinery: Effect of solids loading and enzyme dosage on enzymatic hydrolysis
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-10-18
    Valeria Larnaudie, Mario Daniel Ferrari, Claudia Lareo

    Material and energy results were used in a techno-economic model to analyze the effect of different parameters and configurations on the economics of the process of a liquid hot water pretreated switchgrass (Panicum virgatum L.) biorefinery. Previous experimental results for switchgrass composition and its cellulose enzymatic hydrolysis at different high solids content and enzyme dosages were used in order to obtain a more realistic analysis. The minimum ethanol selling price (MESP) obtained for a facility that produces only ethanol and electricity was within the expected price range for advanced alcohol fuels and could compete with oil prices above $100 per barrel. The MESP was lower for a biorefinery scenario that produces furfural, acetic acid, and formic acid as high-value co-products. The MESP was sensitive to plant size and to switchgrass composition. Enzyme dosage, solids content, and hydrolysis and fermentation efficiencies were the operating parameters with a higher impact on the MESP. Experimental results were combined with the techno-economic models to find correlations between the MESP, and solids content and enzyme dosage. The conditions necessary for a high efficiency of hydrolysis and glucose concentration are not necessarily those that produce an economic optimum (lower cost). The enzyme dosage that minimizes MESP is not always associated with the optimal hydrolysis efficiency (e.g., 95%). The best conditions identified through optimization were an enzyme dosage of 37 mgprotein gglucan−1 and a solids content of 21%, leading to the lowest MESP of $0.84 L-1 (for an enzyme cost of $4.5 kgprotein −1).

  • Monitoring the efficiency of biogas plants – Correlation between gross calorific value and anaerobically non-degradable organic matter of digestates
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-10-17
    Torsten Mächtig, Christian R. Moschner, Eberhard Hartung

    When evaluating the efficiency of biogas plants based on the residual energy content in the digestate, it is necessary to distinguish the anaerobically available and non-available portion of energy. Digestates from agricultural biogas plants typically contain lignin as anaerobically non-degradable matter. The aim of the present study was to examine, if the content of anaerobically non-degradable matter in digestates, as analysed by acid detergent lignin (ADL), can be predicted from gross calorific values (GCV). For that, 31 samples at different degradation states from 9 biogas plants were analysed. The results show that the VS-specific lignin fraction can be predicted from calorimetric measurements in the studied range from 0.03 to 0.36 with an accuracy of ±0.086 (±2*RMSECV). The accuracy of prediction of lignin in digestates was not significantly influenced by the passed hydraulic retention time of the material in the digester. The model equation allows distinguishing anaerobically degradable and non-degradable portions of organic matter and inherent energies in digestates, assuming lignin to be the only non-degradable component. Future efforts have to be made to extend the data set for a greater calibration range of ADL and generalise the model equation for a wider spectrum of biogas plants fed with a variety of substrates.

  • Sugar contents and oligosaccharide mass profiling of selected red seaweeds to assess the possible utilization of biomasses for third-generation biofuel production
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-10-17
    Kusum Khatri, Mangal S. Rathore, Surabhi Agrawal, Bhavanath Jha

    In the present study, we report the sugar contents and oligosaccharide mass profiles of Kappaphycus alvarezii (Doty) Doty ex Silva, Solieria robusta (Greville) Kylin, Gracilaria corticata (J. Agardh), and Gracilaria corticata v. cylindrica Børgesen. Sugar contents in the biomasses of the studied seaweeds indicated that they represent potential sources of raw material for biofuel conversion. Fractionation improved the sugar yield by loosening cell wall components. A Fourier-transform infrared spectroscopy (FTIR) analysis of different cell wall fractions revealed differences in their structural components. Fractionation exposed and released some of the functional groups, depending on the harshness of treatments. However, variable carbohydrate moieties were observed in each fraction. A MALDI TOF-TOF MS analysis of cell wall revealed a complex and dynamic network of polymers in cell walls. K. alvarezii produced the greatest number of oligosaccharide units, followed by S. robusta, G. corticata v. cylindrica and G. corticata. The cell wall of seaweeds was similar to the polymers in the cell wall of higher plants, which indicated the potential to utilize seaweed biomasses for biofuel production. To the best of our knowledge, the present study is the first to report the oligosaccharide mass profiling (OLIMPs) of red seaweeds. A further detailed analysis of the sugar composition of the cell wall and a linkage analysis of OLIMPs would provide detailed structural information. Present results confirmed the potential utilization of red seaweed biomass as an alternative for biofuel production and potential of red seaweed species to be developed as new industrial crops under blue revolution program.

  • 更新日期:2019-10-17
  • Effects of fertilization, plant species, and intra-specific diversity on soil carbon and nitrogen in biofuel cropping systems after five growing seasons
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-10-17
    Jaron Adkins, Julie D. Jastrow, Geoffrey P. Morris, Marie-Anne de Graaff

    Land-use change for bioenergy production can release greenhouse gases (GHG) through disturbance of soil carbon (C) pools, but use of native species with extensive root systems as bioenergy crops may help mitigate GHG emissions by enhancing soil C sequestration. Here, we investigated how (1) fertilization, (2) plant species and cultivars, and (3) inter- and intra-specific diversity affect soil C and N accumulation five growing seasons after conversion of an old-field dominated by C3 grasses to a grassland dominated by C4 perennial grasses managed for biofuel production. We manipulated diversity at both the species- and cultivar level, and applied nitrogen (N) at two levels (0 and 67 kg ha−1). Establishment of C4 grass treatments on soils that supported C3 pasture grasses for 36 years enabled us to use the natural abundance C isotope ratio technique to estimate the contribution of new C4 plant-derived C to soil organic matter pools. Our study yielded three main results: 1) annual fertilization did not significantly affect soil C and N concentrations after five growing seasons; 2) increasing inter- and intra-specific diversity did not significantly increase soil C and N concentrations; 3) cultivar- and species identity influenced C4-derived C and total soil C concentrations: big bluestem dominated stands exhibited greater soil C accrual relative to stands dominated by switchgrass and mixed-species treatments. Future research is needed to further assess how big bluestem can aid in the sustainable provisioning of second generation biofuel feedstocks.

  • Developing biomass estimation models for above-ground compartments in Eucalyptus dunnii and Corymbia citriodora plantations
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-10-08
    Lina Garcia_Florez, Jerome K. Vanclay, Kevin Glencross, J. Doland Nichols

    Biomass has been widely studied in terms of ecosystem ecology, timber production profitability, bioenergy (biofuels) and greenhouse gas emission reduction mechanisms. However, uncertainty in biomass estimation is still a current concern. In this study, direct and indirect methods were used to develop species-specific biomass estimation models (BEMs) for stem, bark, branch and crown compartments in 16-year old plantations of Eucalyptus dunnii and Corymbia citriodora. A total of 93 trees were destructively sampled. An analysis of covariance (ANCOVA) assessed the effect of species on biomass prediction. Our results indicated that equations developed by using parameters or predictors such as diameter at breast height (DBH), height (H), wood density (p) and branch diameter were generally significant (p < 0.05) and their regression lines fitted well the data (R2 > 0.84). After a rigorous process that included testing hypotheses, checking diagnostic statistics, assessing model coefficients and model functionality, the most suitable stem BEMs corresponded to those ones derived from the compound variable DBH2Hp. The most reliable branch and crown BEMs used DBH and branch diameter respectively as single variable (simple linear models). Bark BEMs differ between species as DBH was the best predictor for E. dunnii whilst the compound variable DBH H predicted better for C. citriodora. The BEMs with multiple predictors, and in particular polynomial models, produced wider confidence intervals, unreliable coefficients, multicollinearity and higher proportion of outliers and leverage points. In conclusion, appropriate model diagnosis can reduce pitfalls and ensure selection of valid BEMs.

  • Production of biofuel precursors and value-added chemicals from hydrolysates resulting from hydrothermal processing of biomass: A review
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-10-09
    Paulo C. Torres-Mayanga, Daniel Lachos-Perez, Ackmez Mudhoo, Sunil Kumar, Avery B. Brown, Maksim Tyufekchiev, Giuliano Dragone, Solange I. Mussatto, Mauricio A. Rostagno, Michael Timko, T. Forster-Carneiro
  • Aeration challenge in high BSG suspended fermentation: Impact of stirred-tank bioreactor scale
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-10-01
    H. Moteshafi, S.M. Mousavi, M. Hashemi
  • Understanding catalytic mechanisms of HZSM-5 in hydrothermal liquefaction of algae through model components: Glucose and glutamic acid
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-10-01
    Wenchao Yang, Zhaowei Wang, Shuang Song, Hong Chen, Xiaomeng Wang, Jiayi Cheng, Ruijun Sun, Jianbo Han

    Hydrothermal liquefaction (HTL) of algae has attracted great interest as a thermal conversion for biofuels. In an effort to understand the catalytic mechanism by which algae undergoes HTL in the presence of HZSM-5, the different roles of the major components (carbohydrates and proteins) were investigated. Glucose and glutamic acid were selected as model compounds of carbohydrates and proteins, respectively. Glucose, glutamic acid, and their binary mixtures were processed under hydrothermal conditions in the presence of HZSM-5 over a temperature range of 220–330 °C. The products were analyzed using a combination of elemental analysis (EA), thermal gravimetric analysis (TGA), gas chromatography mass spectrometry (GC-MS), and Fourier transform infrared (FT-IR) spectroscopy to characterize the physicochemical properties. The effects of HZSM-5 on the yield and quality of bio-oil were investigated. Results indicated that the addition of HZSM-5 did not significantly affect the bio-oil yield of glutamic acid but increased the bio-oil yields from glucose and their binary mixtures. The hydrogen-to-carbon (H/C) ratio and the higher heating values (HHVs) of the bio-oils were all greatly increased in the presence of HZSM-5. The addition of HZSM-5 reduced the contents of undesirable oxygenated compounds, nitrogenous compounds, and increased the hydrocarbon content. Maillard reactions between glucose and glutamic acid were also strengthened by HZSM-5.

  • Evaluation of biomass and its thermal decomposition products as fuels for direct carbon fuel cells
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-09-28
    Kai Xu, Jizhou Dong, Xian Li, Junquan Wang, Zhenzhong Hu, Aijun Li, Hong Yao

    Direct carbon fuel cell (DCFC) with biomass as fuel is a promising power generation technology due to the high efficiency of DCFC system and renewability of biomass. This study aims to find the relationship of electrochemical performance between biomass and its thermal decomposition products, and also to reveal their degradation mechanisms during durability tests in solid oxide fuel cells. The thermochemical properties of biomass and biochar, the electrochemical behaviors of biomass, biochar and biogas were characterized comprehensively, and subsequently the degradation process of biomass, biochar and biogas fueled cells were analyzed. The results showed that raw biomass fueled cells produced considerable peak power density (PPD, 0.144 W cm−2 at 1123 K) but experienced rapid discharge degradation. Torrefaction pretreatment (573K) of raw samples compromised PPDs while pyrolysis pretreatment (973K) enhanced PPDs. The electrochemical performance of raw biomass was the combined electrochemical contribution of its decomposition products (biochar and biogas). With biochar as fuel, the power was generated from CO electro-oxidation and biochar-CO2 gasification. Feeding of CO2 into the anode chamber continuously did not improve the output performance. The discharge degradation was mainly caused by the gradually decreasing gasification reactivity of biochar with CO2 and slight anode carbon deposition. With biogas as fuel, the anode reactions were electro-oxidation of active species like H2, CO, CH4, and the cell degraded due to severe carbon deposition. Biomass, biochar and biogas fueled cells all suffered from anode carbon deposits, most of which were in the form of graphitic carbon.

  • Niches for bioelectrochemical systems on the recovery of water, carbon and nitrogen in wastewater treatment plants
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-09-27
    Miguel Osset-Álvarez, Laura Rovira-Alsina, Narcis Pous, Ramiro Blasco-Gómez, Jesús Colprim, M. Dolors Balaguer, Sebastià Puig
  • Lipid production in Rhodosporidium toruloides using C-6 and C-5 wood hydrolysate: A comparative study
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-09-27
    Carlos S. Osorio-González, Krishnamoorthy Hegde, Pedro Ferreira, Satinder Kaur Brar, Azadeh Kermanshahipour, Carlos Ricardo Soccol, Antonio Avalos-Ramírez

    Rhodosporidium toruloides is an oleaginous yeast that can accumulate up to 70% of its dry biomass as lipids and can use C5 and C6 sugars as a carbon source, that are present in hydrolysates from different lignocellulosic biomass. R. toruloides can be an alternative for the valorization of forestry residues and the obtention of higher value-added products. In this study, five strains of R. toruloides were evaluated to find the most efficient yeast strain for C5 and C6 sugars utilization, using lignocellulosic hydrolysates as a culture media. Sugar consumption was similar between all strains. Nevertheless, it was different among C6 and C5 hydrolysates, with maximum sugar utilization of 98%, and 60% for C6 and C5 hydrolysate, respectively. Among the studied strains, the highest lipid production was observed in R. toruloides-1588 with 23.33 g of lipids/L in C6 hydrolysate after 112 h. Whereas, highest lipid production in C5 hydrolysate was observed in R. toruloides-7191 with 14.67 g of lipids/L after 120 h. Predominantly, fatty acids for R. toruloides-1588 was oleic, palmitic, and stearic acids and pentadecanoic, palmitic, and heptadecanoic acids for R. toruloides-7191. Moreover, both strains grew and produced lipids in the presence of inhibitor compounds, such as levulinic acid (13.88 mgL−1), 5-HMF (80.86 mgL−1), furfural (153.54 mgL−1), vanillin (17.17 mgL−1), vanillic acid (85.25 mgL−1), syringaldehyde (41.83 mgL−1), ferulic acid (1.66 mgL−1), and 4-hydroxybenzoic acid (0.85 mgL−1). The study revealed that R. toruloides-1588 and R. toruloides-7191 are promising strains for C5 and C6 sugar utilization from lignocellulosic hydrolysates for lipid production.

  • Dispersed air flotation of microalgae using venturi tube type microbubble generator
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-09-27
    Kazuhiro Itoh, Yasuhiro Kashino, Kentaro Ifuku, Maeda Kouji, Takuji Yamamoto, Shogo Taguchi

    To evaluate biodiesel production from microalgae, a flotation experiment was conducted using the living cell culture fluid of the diatom Chaetoceros gracilis using a venturi tube type microbubble generator. We compared the separation performance of three different culture periods: 1, 2, and 3 weeks from the start of cultivation. After 1 week, the cells were in the logarithmic growth phase, while after 2 and 3 weeks, cell growth had reached the stationary phase. The amounts of triacylglycerol (TAG) in the foam on the surface of the fluid tank were measured. TAG increased during the first 20 min after the start of circulation without additional coagulants and pH adjustment. The disruption of cells was achieved simultaneously. The amounts of TAG in the culture fluids at weeks 2 and 3 were higher than those at week 1. C. gracilis cells in the stationary phase accumulated large amounts of TAG and were easy to disrupt by pressure fluctuation in the venturi tube. These results provide insight into the fracture strength and buoyance of cells for efficiently separating the cells from large volumes of culture fluid.

  • Constitutive modelling of compression and stress relaxation in pine pellets
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-09-26
    Simon Klinge Nielsen, Hamid Rezaei, Matthias Mandø, Shahab Sokhansanj

    The increasing pellet production and a demand for making high quality biofuel pellets call for tools that can facilitate producers to meet these requirements and help understanding the effect feedstock and process parameters. In this study, mechanical and rheological properties of pine pellets made of different particle sizes and compression speeds were studied via pelleting tests and numerical simulations. Single pelleting tests were performed with six different particle size samples, ranging between 0.25 and 2.8 mm, and pelleted at compression speeds of 1, 5, and 10 mm min−1. The experimental results of specific compression and extrusion energy showed a positively linear correlation between particle size and energy consumption. The highest pellet durability was observed for pellets produced from small and mixed particle sizes. Eight different constitutive models were evaluated on their ability to simulate compression and stress relaxation, and their level of complexity. A non-linear Maxwell representation of the Standard Linear Solid (SLS) model was setup and fitted to the experimental compression data. The model coefficient of spring 1 composes the asymptotic stress level of the relaxed pellet, and the coefficient of spring 2 was found to be positively correlated with particle size. The viscosity of the dashpot is also found to be positively correlated with particle size, likewise it depends on the compression speed, where higher compression speed resulted in lower viscosities. The results of the study elucidate new insight into mechanical behavior of biomass particle compression, and the resultant simulations have utility for predicting the pressure requirements to produce pellets.

  • Alcoholic fermentation of thermochemical and biological hydrolysates derived from Miscanthus biomass by Clostridium acetobutylicum ATCC 824
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-09-26
    Mahendra P. Raut, Trong K. Pham, Leonardo D. Gomez, Ioanna Dimitriou, Phillip C. Wright

    This laboratory scale study aims to demonstrate the effectiveness of thermochemical and biological saccharification of Miscanthus giganteus (MG) for generation of fermentable saccharides and its subsequent fermentation into solvents i.e. acetone, ethanol and butanol (ABE) using Clostridium acetobutylicum ATCC 824. Saccharide hydrolysates were derived from MG by thermochemical (water, acid and alkali at 130 °C) and biological saccharification (Fibrobacter succinogenes S85) processes and were subjected to batch fermentation for 120 h using C. acetobutylicum ATCC 824. At the end of fermentation of thermochemically-derived hydrolysates, 742 g m−3 of saccharides from water treatment, 9572 g m−3 of saccharides from acid treatment and 4054 g m−3 of saccharides from alkali treatment were fermented and yielded 0.045, 0.0069 and 0.01 g g−1 of total solvents, respectively. Similarly, at the end of fermentation of biological hydrolysate (using F. succinogenes), 2504 g m−3 of saccharides was fermented and yielded 0.091 g g−1 of total solvents. The highest yield of total solvents was achieved by water (thermochemical) and biological saccharification of MG using C. acetobutylicum. Whereas, acid and alkali-treated hydrolysates showed lower yields of solvents presumably due to production of inhibitory compounds during saccharification. Compared to thermochemical saccharification, biological saccharification using F. succinogenes is a promising approach since it yielded the highest amount of solvents whilst being eco-friendly. Our future studies will focus on optimisation of biological saccharification (using F. succinogenes) and sequential co-culture fermentation (using C. acetobutylicum). The development of alternative consolidated bioprocessing approach using biological saccharification will contribute towards making lignocellulosic biofuels a reality.

  • The effect of temperature and moisture on the chosen parameters of briquettes made of shredded logging residues
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-09-26
    Tomasz Nurek, Arkadiusz Gendek, Kamil Roman, Magdalena Dąbrowska

    The aim of this work was to determine the effect of compaction parameters of shredded logging residues on the durability of obtained briquettes. Logging residues have a different composition than raw materials currently used in the agglomeration process, because they contain a high amounts of bark, needles and mineral contaminations. The innovation of this study results from the type of biomass used in the research – non-homogenous fraction containing significant amounts of needles and non-woody parts. Correlation between the physical properties of obtained briquette and raw material parameters and the course of briquetting process were determined. Biomass was compacted in a special designed closed die. The investigated material with moisture contents of 10, 15, 20% was compacted at temperatures of 22 and 73 °C. Single briquettes with a density from 799 to 1215 DM kg·m−3 at the compaction index values ranging from 27.73 to 35.37 (J g−1)/(g·cm−3), respectively were obtained. For both temperatures 22 and 73 °C, the highest values of durability coefficient were obtained for 10% moisture content and they were 16% and 22%, respectively which were not satisfying durability. It was also found that the temperature of material during agglomeration influences its susceptibility to compaction and durability of obtained briquettes and that it is more advantageous to carry out the compaction at a higher temperature. On the other hand, the higher temperature of the agglomeration process affects the increase in specific work of compaction which to a small extent depends on the moisture content of the material.

  • Analysis of current aviation biofuel technical production potential in EU28
    Biomass Bioenergy (IF 3.537) Pub Date : 2019-09-26
    M. Prussi, A. O'Connell, L. Lonza

    The significant growth aviation has been observing is increasing the sector's pressure on the environment; in the EU28, passengers travelling by air in 2016 increased of 5.9% compared to 2015. The aviation industry voluntarily committed to significant aspirational goals, and identified bio-based aviation fuels as a potential means to improve its environmental performance. Despite of that, the market penetration of aviation biofuels in EU28 is almost negligible. In this paper, an assessment of the likely aviation biofuels demand has been carried out, under a baseline scenario of increasing total fuel consumption of +3% for 2016–2020 and + 3.5% up to 2030; the CO2 intensity of this growth has been calculated accordingly. Europe is a World leader in biofuel technologies; the current potential aviation biofuels is based on the HVO/HEFA technology, and the upper limit of the installed capacity can be considered approximately 2.4 Mt y−1. Nevertheless, lower production volumes can be expected as production plants are today optimized for road fuel production, not aviation. By 2025 the situation may change, with a total production capacity of 3.5 Mt y−1, and with an average potential production for aviation biofuels ranging 0.5–2 Mt y−1. The paper shows that even if today's EU nominal capacity appears large enough to support the expected aviation biofuels demand, other bottlenecks may limit the real market uptake: availability of sustainable feedstocks, competition with demand for road transport sector, etc. For this reason, a comparison of the cost for CO2 saving of other potential solutions to mitigate aviation's climate impact has also been carried out.

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上海纽约大学William Glover