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The current trend of using plastic material in the manufacturing of packaging products raises serious environmental concerns due to waste disposal on land and in oceans and other environmental pollution. Natural polymers such as cellulose, starch, chitosan, and protein extracted from renewable resources are extensively explored as alternatives to plastics due to their biodegradability, biocompatibility, nontoxic properties, and abundant availability. The tensile and water vapor barrier properties and the environmental impacts of natural polymers played key roles in determining the eligibility of these materials for packaging applications. The brittle behavior and hydrophilic nature of natural polymers reduced the tensile and water vapor barrier properties. However, the addition of plasticizer, crosslinker, and reinforcement agents substantially improved the mechanical and water vapor resistance properties. The dispersion abilities and strong interfacial adhesion of nanocellulose with natural polymers improved the tensile strength and water vapor barrier properties of natural polymer-based packaging films. The maximum tensile stress of these composite films was about 38 to 200% more than that of films without reinforcement. The water vapor barrier properties of composite films also reduced up to 60% with nanocellulose reinforcement. The strong hydrogen bonding between natural polymer and nanocellulose reduced the polymer chain movement and decreased the percent elongation at break up to 100%. This review aims to present an overview of the mechanical and water vapor barrier properties of natural polymers and their composites along with the life cycle environmental impacts to elucidate their potential for packaging applications. [ABSTRACT FROM AUTHOR]

Abstract Torrefaction is a thermal pretreatment method to increase the energy density and to decrease the grinding energy of biomass. In this study, the torrefaction of two types of commercially available wood pellets was carried out in the temperature range of 230–290 °C for 30 min residence time. Torrefaction produces both the solid fuel known as torrefied pellets and the volatile stream known as torgas. The torgas was further separated into condensable liquids, known as tor-liquid and non-condensable gases. The products yield, its compositions and fuel properties at various torrefaction temperatures were also determined. The increase in temperature reduced the torrefied pellet yield from 89 to 52%, while increased the condensable liquid yield from 5 to 23% within the torrefaction study condition. The heating value (24 MJ kg−1) and the volumetric energy density (12.5 GJ m−3) of torrefied pellets at 270 °C were comparable to that of coal for biopower. The increase in torrefaction temperature improved the hydrophobicity (resistance to water uptake), but adversely reduced the pellet density, hardness, and durability of torrefied pellets causing high susceptibility to breakage and fine generation during handling, transport, and storage. Further research is required to improve the quality of torrefied pellets for safe handling and storage. The non-condensable fraction of torgas was mainly composed of carbon dioxide, carbon monoxide, and traces of methane. The condensable liquid was rich in organic acids, ketones, furfural, and levoglucosan, which could be potentially transformed into high-value chemicals and other commercially viable products. Highlights • Torrefied pellet yield reduced from 89 to 52% between 230 and 290 °C. • Torrefied pellets produced at 270 °C had similar fuel properties as coal. • TAP pathway improved the hydrophobicity of wood pellets. • Pellet hardness and durability decreased with increased torrefaction temperature. • Tor-liquid was rich in organic acids, and levoglucosan and can be a co-product. [ABSTRACT FROM AUTHOR]

The assessment of biomass at high spatial resolution is critical to manage supply risks and to identify optimal plant sites for producing sustainable biofuels and co-products. The spatial variabilities in soil type, topography, climate, and crop management practices further require vast computational time and resources to estimate the availability of sustainable biomass for a large study area. In this study, we developed a GIS-based integrated predictive modeling platform to assess the availability of sustainable crop residues at high spatial (30 m) and temporal (2010–2022) scales. A GIS-based multi-criteria inclusion-exclusion analysis and facility location-allocation models were used to identify suitable sites, and optimal siting of biogas plants respectively with biomass delivered cost. The Artificial Neural Network (ANN) based predictive models were well suited to predict sustainability indicators (soil erosion SE- R 2 = 0.96, soil conditioning index, SCI R 2 = 0.98 and organic matter factor, OMF- R 2 = 0.83) for assessing sustainable removal rates of crop residues (corn stover and wheat straw). The GIS-based integrated model was applied to the State of Ohio and found that about 4–13 dry Tg of crop residues can be sustainably available to build 1–25 regional biogas plants. A typical optimal biogas plant with a feedstock capacity of up to 500 dry Gg could be drawn from a transport radius of about 19–35 km with a delivered cost of 40–46 $ dry Mg −1 . The temporal and spatial variations in assessing the availability of biomass largely affected the supply chain decisions and its delivered costs. [ABSTRACT FROM AUTHOR]

Cellulose nanofibrils (CNFs) are typically produced via wet milling pretreatment method to facilitate efficient disintegration of cellulose fibers by pre-fibrillation and fiber size reduction. However, the use of high energy and presence of water during wet milling methods leads to the increase in overall energy consumption during CNFs production and pose challenges during storage and handling. The objective of this study is to investigate the dry grinding of cellulose fluff pulp using the shear cutting method to determine the specific energy required to produce cellulose precursors and their characteristics for manufacturing CNFs. The specific energy required to grind cellulose fluff pulp with a screen size of 0.25 mm in three cycles was measured. The ground sample received after each cycle was sampled to characterize its properties and its potential to produce CNF hydrogels. As the number of grinding cycles increased, the specific energy required per cycle decreased with an overall net energy consumption of 894 kWh/Mg for three grinding cycles. The cellulose powder from the third grinding cycle was successfully disintegrated into cellulose nanofibrils with an average diameter of 119 nm without any fiber clogging. In conclusion, the three-cycle shear cutting process was sufficient to produce dry cellulose precursors for CNFs production, while reducing the overall energy consumption and handling and storage problems. [ABSTRACT FROM AUTHOR]

Storage of agricultural residues and energy crops is essential for preserving and maintaining its economic value, and year-round continuous delivery to a biorefinery. In this study, a dynamic cost model was developed for three storage methods (Indoor, Outdoor-tarped, and Outdoor-open) with two biomass bale types (rectangular and round) to estimate the storage cost of corn stover and switchgrass. The effects of storage time and multiple-use of a storage facility on the storage cost were also evaluated to develop effective storage strategies. The cost of bale storage systems comprised of capital expenses for infrastructures, bale handling, dry matter loss ( DML) and quality loss costs. Among storage methods, the outdoor-tarped storage with rectangular bales was the least expensive options for corn stover ($14.6 dry Mg−1) and switchgrass ($16 dry Mg−1). Indoor storage of round bales was costly due to the large storage footprint requirement and high infrastructure investment. However, the indoor storage cost could be reduced, if the storage facility could be used more than once a year. The sensitivity analysis study illustrated that the DML, biomass cost, loading/unloading time and bale density were the most sensitive parameters influencing the storage cost. An example storage strategy developed for a typical biorefinery could reduce the average annual storage cost (up to $10 dry Mg−1) along with an annual cost saving ranging from 10 to 100% compared with any single storage option. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Biogas derived from anaerobic digestion of organic wastes, and lignocellulosic biomass can be used to produce drop-in diesel fuel via Fischer-Tropsch ( FT) synthesis. In this study, we developed a process-based simulation model for the biogas to liquid fuel ( BgTL) plant to conduct mass and energy balances and to evaluate techno-economic assessment of producing drop-in FT fuels. The BgTL plant operations consisted of biogas cleaning, biomethane reforming, FT synthesis of syngas and hydrocracking and final distillation to produce drop-in liquid fuels. The unconverted syngas and syncrude were utilized to generate steam and electricity to meet internal plant demand, while the excess power was sold to the grid. The base case BgTL plant (2 000 Nm3/h) produced about 4.6 million gallons per annum of total FT fuels which consisted of 62% diesel, 32% gasoline, 6% LPG with an overall biogas conversion of 54%. A discounted cash flow rate of return ( DCFOROR) approach for the Nth plant was used to estimate the capital and operating costs with the minimum selling price for the FT drop-in fuels of about $5.67/gal ($5.29/ GGE). The increase in plant feed capacity to 20 000 Nm3/h decreased the minimum selling price to $2.06/gal ($1.92/ GGE). The sensitivity analysis conducted on the base case plant demonstrated that the internal rate of return ( IRR), FT conversion rate, plant operating hours, and biogas cost were the most sensitivity parameters to the minimum selling price. Overall, the BgTL technology is deemed to be economically feasible to meet US biofuels demand. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Iron supported biochar catalysts were used to decompose toluene, a model tar compound, over a temperature range of 600–900 °C. Toluene conversion and decomposition rates increased linearly with increasing temperature and catalyst loading from 600 to 700 °C. Relative to biochar alone, the iron supported catalysts lowered the activation energy by 47% and decreased the formation of benzene, an intermediate in toluene decomposition. At 800 °C for the 13 and 18.7 wt.% iron loaded catalyst, toluene conversion approached 100% and benzene selectivity (S B ) was zero, compared to an S B of 0.025% and 0.35% for 10% iron and the biochar, respectively. Time on stream studies with the 13 wt.% iron biochar catalyst, over the course of four days, resulted in a mean toluene conversion of 91% and benzene selectivity of 0.02%. These results indicate that inexpensive iron impregnated biochar catalysts could potentially be used to catalytically decompose tar molecules in syngas generated via biomass gasification. [ABSTRACT FROM AUTHOR]

Densification of switchgrass into consistent and high-density solid feedstock will reduce the cost of transport, handling, and storage to produce fuels and chemicals. Development a novel, low-cost densification technology is critical for reducing the delivered cost of feedstock while improving the bulk flow properties of densified products. In this paper, a novel wet granulation technology was proposed to investigate the effect of lime pretreatment on the production of switchgrass granules. Granulation is a process of agglomerating fine powders by wetting powder surfaces with liquid binders and mild application of shear/vibrating forces. Switchgrass was size reduced into fine powders using a knife mill and pretreated with three lime loading rates (0.05, 0.1, 0.2 g/g of biomass) at 121 °C for 30 min and at room temperature (25 °C) for 72 h. The structural modification of pretreated samples was analyzed by scanning electron microscopy and autofluorescence microscopy. Pretreated samples were granulated using a pan granulator with pre-formulated starch binder. Granules made from 20 % (0.2 g/g of biomass) lime loading rate had significantly higher single granule density and angle of repose with lower binder requirement than that of untreated granules. Lime treatment did not significantly increase the bulk density and hardness of granules. Lime-treated granules had significantly higher ash content and lower gross calorific value than that of untreated granules. In overall, lime treatment was not attractive to produce granules for thermochemical conversion platform, but lime-treated granules could be used to produce liquid biofuels and platform chemicals in biochemical conversion platform. [ABSTRACT FROM AUTHOR]

Pine bark biochar generated by slow pyrolysis (950°C) was used as a low cost catalyst to decompose toluene (model tar compound) over a temperature range of 600–900°C. Relative to thermal cracking, fractional toluene conversion increased from 13 to 94% when increasing temperatures from 600 to 900°C (2500ppmv, SV=0.76s−1, 3.8g catalyst) and Arrhenius analysis indicated an activation energy of 91kJ/mol, comparable to that of synthetic catalysts (e.g., 80.24kJ/mol for Ni/Mayenite and 196kJ/mol for olivine) and lower than that of thermal cracking (356kJ/mol). The reaction rate for toluene decomposition increased linearly from 550 to 700°C with a concentration range of 1000–4600ppmv indicating a first order rate law with respect to toluene. Benzene was detected as a potential intermediate in the decomposition of toluene with selectivity ranging from 0 to 28% at temperatures from 600 to 900°C respectively, and its formation increased with increasing toluene conversion. Toluene conversion ranged between 40 and 95% with benzene selectivity from 0 to 20% at 800°C during catalyst longevity studies of 6days. These results indicate that biochar generated from slow pyrolysis of pine bark at high temperature can be used as a low cost catalyst for tar removal from syngas. However, the tar removal rates using the biochar catalyst were lower than that of olivine and nickel based catalysts indicating the need to increase catalytic activity. [ABSTRACT FROM AUTHOR]

In recent years, the demand for environmental sustainability has caused a great interest in finding novel polymer materials from natural resources that are both biodegradable and eco-friendly. Natural biodegradable polymers can displace the usage of petroleum-based synthetic polymers due to their renewability, low toxicity, low costs, biocompatibility, and biodegradability. The development of novel starch-based bionanocomposites with improved properties has drawn specific attention recently in many applications, including food, agriculture, packaging, environmental remediation, textile, cosmetic, pharmaceutical, and biomedical fields. This paper discusses starch-based nanocomposites, mainly with nanocellulose, chitin nanoparticles, nanoclay, and carbon-based materials, and their applications in the agriculture, packaging, biomedical, and environment fields. This paper also focused on the lifecycle analysis and degradation of various starch-based nanocomposites. [ABSTRACT FROM AUTHOR]

Abstract: Thermal pretreatment or torrefaction of biomass under anoxic condition can produce an energy dense and consistent quality solid biomass fuel for combustion and co-firing applications. This paper investigates the fuel characteristics and grindability of pine chips and logging residues torrefied at temperatures ranging from 225°C to 300°C and 30min residence time. Grinding performance of torrefied biomass evaluated by determining energy required for grinding, particle size distribution and average particle size were compared with raw biomass and coal. Specific energy required for grinding of torrefied biomass decreased significantly with increase in torrefaction temperatures. The grinding energy of torrefied biomass was reduced to as low as 24kWh/t at 300°C torrefaction temperature. The gross calorific value of torrefied chips increased with increase in torrefaction temperature. Torrefaction of biomass clearly showed the improved fuel characteristics and grinding properties closer to coal. [ABSTRACT FROM AUTHOR]

Abstract: Corn stover is a major crop residue for biomass conversion to produce chemicals and fuels. One of the problems associated with the supply of corn stover to conversion plants is the delivery of feedstock at a low cost. Corn stover has low bulk density and it is difficult to handle. In this study, chopped corn stover samples were compacted in a piston cylinder under three pressure levels (5, 10, 15MPa) and at three moisture content levels (5%, 10%, 15% (wb)) to produce briquettes. The total energy requirement to compress and extrude briquette ranged from 12 to 30MJ/t. The briquette density ranged from 650 to 950kg/m3 increasing with pressure. Moisture content had also a significant effect on briquette density, durability and stability. Low moisture stover (5–10%) resulted in denser, more stable and more durable briquettes than high moisture stover (15%). [Copyright &y& Elsevier]

Abstract: Mechanical properties of wheat straw, barley straw, corn stover and switchgrass were determined at different compressive forces, particle sizes and moisture contents. Ground biomass samples were compressed with five levels of compressive forces (1000, 2000, 3000, 4000 and 4400N) and three levels of particle sizes (3.2, 1.6 and 0.8mm) at two levels of moisture contents (12% and 15% (wet basis)) to establish compression and relaxation data. Compressed sample dimensions and mass were measured to calculate pellet density. Corn stover produced the highest pellet density at low pressure during compression. Compressive force, particle size and moisture content significantly affected the pellet density of barley straw, corn stover and switchgrass. However, different particle sizes of wheat straw did not produce any significant difference on pellet density. The relaxation data were analyzed to determine the asymptotic modulus of biomass pellets. Barley straw had the highest asymptotic modulus among all biomass indicating that pellets made from barley straw were more rigid than those of other pellets. Asymptotic modulus increased linearly with an increase in compressive pressure. A simple linear model was developed to relate asymptotic modulus and maximum compressive pressure. [Copyright &y& Elsevier]

Unprecedented opportunities for biofuel development are occurring as a result of rising fossil fuel prices, the need to reduce greenhouse gases, and growing energy security concerns. An estimated 250 million hectares (ha) of farmland could be utilized globally to develop a bioenergy industry if efficient and economical perennial biomass crops and bioenergy conversion systems are employed. In temperate zones, C 4 or warm-season grass research and development efforts have found switchgrass (Panicum virgatum) and Miscanthus capable of producing biomass yields of 10 to 20 oven dried tonnes (ODT)/ha/yr, while in tropical areas Erianthus and napier grass (Pennisetum purpureum) are producing 25 to 35 ODT/ha/yr. The potential to annually produce 100 barrels of oil energy equivalent/ha with a 25:1 energy output to input ratio appears achievable with high-yielding, N-fixing warm-season grasses grown on marginal lands in the tropics. Commercialization of densified herbaceous plant species has been slow because of the relatively high alkali and chlorine contents of the feedstocks, which leads to clinker formation and the fouling of boilers. This challenge can be overcome by improving biomass quality through advances in plant breeding and cultural management to reduce the chlorine, alkali, and silica content and through the use of new combustion technologies. Warm-season grasses can be readily densified provided suitable grinding and densification equipment and pressure are utilized. The major advantages of producing densified warm-season grasses for BIOHEAT include: it is the most efficient strategy to use marginal farmlands in most temperate and tropical climates to collect solar radiation; it has an excellent energy balance; the feedstocks can be used conveniently in a variety of energy applications; and it is relatively environmentally friendly. Densified warm-season grass biofuels are poised to become a major global fuel source because they can meet some heating requirements at less cost than all other alternatives available today. [ABSTRACT FROM AUTHOR]

Wheat and barley straws, corn stover and switchgrass at two moisture contents were ground using a hammer mill with three different screen sizes (3.2, 1.6 and 0.8 mm). Energy required for grinding these materials was measured. Among the four materials, switchgrass had the highest specific energy consumption (27.6 kW h t-1), and corn stover had the least specific energy consumption (11.0 kW h t-1) at 3.2 mm screen size. Physical properties of grinds such as moisture content, geometric mean diameter of grind particles, particle size distribution, and bulk and particle densities were determined. Second- or third-order polynomial models were developed relating bulk and particle densities of grinds to geometric mean diameter within the range of 0.18–1.43 mm. Switchgrass had the highest calorific value and the lowest ash content among the biomass species tested. [Copyright &y& Elsevier]

Anaerobic Digestion (AD) is a well-developed sustainable technology to convert organic waste streams and energy crops to produce renewable gaseous biofuels, while recycling nutrients and mitigating greenhouse gas emissions. In this study, the environmental and economic impacts of an integrated-state AD technology (i -AD) producing Compressed Natural Gas (noted as BioCNG) were investigated from dairy-manure, food-wastes, and miscanthus biomass feedstocks, and compared with that of stand-alone liquid-state (LS-AD) and solid-state (SS-AD) AD technologies. A coupled life-cycle assessment and techno-economic analysis (LCA‐TEA) approach was used to estimate the Global Warming Potential (GWP) and the Minimum Selling Price (MSP) of BioCNG ‒ a renewable alternative to fossil-CNG. The results illustrated that the Fossil Energy Ratios (FERs) for BioCNG were between 2.3 and 3.3 in the increasing order as LS‐AD < i ‐AD < SS‐AD. The life-cycle GWPs to produce BioCNG via LS‐AD, SS‐AD, and i ‐AD were −5.1, −15.1, and −12.0 kgCO 2 eq/GGE (Gasoline-Gallon-Equivalent) respectively. The MSP of BioCNG (without incentives) via LS‐AD ($2.9/GGE) was lower than that of both SS‐AD ($4.1/GGE) and i ‐AD ($4.9/GGE). When the tipping-fee ($44/Mg), RIN(Renewable Index Number)-credit ($0.46/RIN), and carbon-credit($13.6/MgCO 2 eq) were considered, the MSP of BioCNG dropped by up to 70%, 45%, and 25% for LS‐AD, SS‐AD, and i ‐AD, respectively. Fungal-pretreatment of miscanthus had negligible impacts on the environmental and economic performances of BioCNG. Backhauling of solid-digestate for miscanthus cultivation may reduce the MSP, energy usage, and GWP by up-to 5%, 16%, and 7%, respectively. The commercial production of BioCNG from energy crops can potentially be competitive at a higher BioCNG market price or with favorable energy policies, financial support, and tax-benefits. Image 1 • BioCNG production of an integrated-state AD technology was studied. • The Global Warming Potential of BioCNG ranged from −5 to −15.0 kgCO 2 eq per GGE. • The Minimum Selling Price of BioCNG ranged from $3 to $5 per GGE without any credit. • The solid-state AD technology to produce BioCNG from miscanthus was very promising. • BioCNG through solid-state AD can be economical at a carbon price of $35/MgCO₂eq. [ABSTRACT FROM AUTHOR]

We investigated the techno-economic analysis of two integrated torrefaction and pelletization systems: (1) Torrefaction befOre Pelletization and (2) Torrefaction After Pelletization configurations to produce torrefied wood pellets. The detailed mass and energy balances and operating parameters were obtained from the process simulation model developed with the base case plant capacity of 100,000 Mg yr−1 using natural gas as an auxiliary fuel source. A discounted cash flow analysis was conducted for both configurations to estimate the capital expenditure, operating expenses, production cost, and the minimum selling price of torrefied pellets. The minimum selling price of torrefied pellets at the plant gate was $207 Mg−1 ($8.5 GJ−1) for the Torrefaction before Pelletization and $197 Mg−1 ($8.1 GJ−1) for the Torrefaction After Pelletization configurations. An increase in the plant capacity of up to 200,000 Mg yr−1 for both configurations decreased the minimum selling price by 10%. The sensitivity analysis of various operational and financial parameters demonstrated that the feedstock cost and torrefaction product yield were the most sensitive parameters influencing the minimum selling price of torrefied pellets. Future opportunities exist to reduce the minimum selling price of torrefied pellets to become competitive to conventional wood pellets and coal. [Display omitted] [ABSTRACT FROM AUTHOR]

Localized carbon reduction strategies are especially critical in states and regions that lack top-down climate leadership. This paper illustrates the use of coupled systems in assessments of subnational climate solutions with a case study of Georgia, a state located in the southeastern United States that does not have statewide climate goals or plans. The paper illustrates how robust place-specific plans for climate action could be derived from foundational global and national work and by embedding that research into the context of socio-ecological-technological systems. Our replicable methodology advances the traditional additive sectoral wedge analysis of carbon abatement potential by incorporating solution interdependencies and by spanning both carbon sources and sinks. We estimate that a system of 20 solutions could cut Georgia's carbon footprint by 35% in 2030 relative to a business-as-usual forecast and by 50% relative to Georgia's emissions in 2005. We also produce a carbon abatement cost curve that aligns private and social costs as well as benefits with units of avoided CO2-e. The solutions are affiliated with various social cocosts and co-benefits that highlight societal concerns extending beyond climate impacts, including public health, environmental quality, employment, and equity. [ABSTRACT FROM AUTHOR]

Abstract Storage is the critical operation within the biomass supply chain to reduce feedstock supply risks and to manage smooth year-around operations of a biorefinery or a bioenergy plant. This paper analyzed the economic and environmental impacts of four different biomass storage systems for woodchips (Outdoor-open, Outdoor-tarped, Indoor, and Silo) and two systems for pellets (Indoor and Silo). Storage cost includes the costs for handling (including ventilation in case of silo storage), infrastructure investment, and dry matter loss (DML) for each system. The estimation of total greenhouse gas (GHG) emissions includes the fugitive emissions from storage piles and emissions due to electricity and fuel consumption for each system. Among four storage systems, the outdoor-tarped ($15.0 ODMT−1, ODMT: Oven Dry Metric Ton) and silo ($5.8 ODMT−1) storage were the least-cost options for woodchips and pellets respectively. However, silo-storage could be the most promising option for storing woodchips ($5.8 ODMT−1) and pellets ($2.3 ODMT−1), if it is used for short-term (two months) and frequently (at least six times) in a year. The total GHG emissions for six-month storage were 2.8–11.8 kgCO 2 e ODMT−1 for woodchips and 8.6–42.0 kgCO 2 e ODMT−1 for pellets. During Outdoor-open storage, the lower heating value of woodchips could drop to 37% due to increased dry-matter loss (DML) and moisture content. The initial moisture content, bulk density, DML, and resource required during handling were the most sensitive parameters influenced the storage performances of both woodchips and pellets. This study has demonstrated that a combination of different storage options along the supply chain could reduce the total biomass storage cost for a biorefinery or power plant. Graphical abstract fx1 Highlights • Large-scale storage options for storing woodchips and pellets were studied. • The outdoor-open storage was the least-cost option for long-term storage of woodchips. • Bin/silo storage was the best option for short-term storage of woodchips and pellets. • The average bin storage cost ranged from 2 to 22 ODMT−1. • All storage systems had low energy use and GHG emissions. [ABSTRACT FROM AUTHOR]

Abstract Torrefaction of biomass improves the grindability of raw biomass by the transformation from a fibrous structure to a more brittle and friable, coal-like material. Torrefied biomass is a more desirable feedstock for co-firing applications, especially in existing coal-fired power plants. Therefore, measuring the grindability and the specific energy consumption are critical for understanding the comminution behavior of torrefied biomass, and thus selecting appropriate milling equipment. In this study, the effect of torrefaction temperature on the specific grinding energy consumption and the grindability of torrefied wood pellets and wood chips was investigated and compared with that of coal. The applicability of three well-known grinding equations (Kick, Rittinger and Bond) was studied for the torrefied biomass using a knife mill. The specific grinding energy of both torrefied wood chips and pellets linearly decreased with increased torrefaction temperature over a range of 250–290 °C. Rittinger's model was the best-fit for both wood chips (R2 = 0.72–0.90) and wood pellets (R2 = 0.67–0.76). When the intercepts were considered, the Rittinger's and Bond's equations fitted well with the experimental data (R2 = 0.79–0.99) for all torrefied biomass. The grindability of torrefied biomass was measured using the Hardgrove Grindability Index (HGI) and the International Organization for Standardization (ISO) grindability index. A relationship between the Bond Work Index (BWI), based on the Bond's theory and HGI was developed for wood chips and wood pellets. Contrary to HGI index, BWI decreased with an increase in torrefaction temperature. The grindability parameters developed for torrefied biomass can be used for modeling and selecting suitable milling equipment. Highlights • Specific grinding energy required for torrefied wood chips and pellets were determined • Grinding energy decreased linearly with increased torrefaction temperature (250–290 °C) • Rittinger's equation was fitted the best with grinding data for all torrefied biomass. • HGI and BWI for torrefied biomass produced at 290 °C were comparable to that of coal. [ABSTRACT FROM AUTHOR]

Woody biomass feedstock that is both high quality and low cost has become increasingly important for the bioenergy and bioproducts industries. Logging generates forest residues – low‐quality feedstock – and additional operations that also incur additional costs, such as biomass sorting and treetops processing (BSTP), micro‐chipping, and screening, which are required to improve the feedstock's quality. Considering recent developments in technologies and BSTP to generate high‐quality feedstocks, economic models were developed in this study to estimate various forest‐residue logistics operational costs and to analyze the economics of delivering feedstocks to biomass conversion technology (BCT) sites near woods or power plants located far away in the form of chips, hog fuel, and bales. The results show that the cost of BSTP can vary between $30 and $82/ODMT (oven dry metric ton) based on the biomass sorting intensity. The most economical way to deliver forest residues was transporting processed stem‐wood from landings to near‐wood BCT sites and comminuting it into woodchips there (~$20/ODMT, assuming a one‐way (32 km) road distance and no cost of BSTP at landings). Grinding slash at the landing and transporting ground‐biomass (i.e., hog fuel) to a plant (< 22 km away) was more economical than transporting bales from landings and grinding at the plant. The economic feasibility of baling and BSTP requires a substantial productivity improvement or recognition and incorporation of benefits including reduced wildfire risk and improved forest health. High bulk density and strong shape of forest residues/slash bales compared to hog fuel may provide additional cost benefits during storage, for example through lower handling costs, which can be studied in the future. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Highlights • Economic feasibility of portable systems to utilize forest residues was investigated. • Forest residues were processed into raw and torrefied briquettes and biochar. • Minimum selling price (MSP) of biochar was estimated to $1044/ODMT. • MSP of raw and torrefied-briquettes were $162 and $274/ODMT respectively. • MSPs could be reduced by at least 50% with improved portable systems. Abstract Wildfires are getting extreme and more frequent because of increased fuel loads in the forest and extended dry conditions. Prevention of wildfire by fuel treatment methods will generate forest residues in large volumes, which in addition to available logging residues, can be used to produce biofuels and bioproducts. In this study, the techno-economic assessment of three portable systems to produce woodchips briquettes (WCB), torrefied-woodchips briquettes (TWCB) and biochar from forest residues were evaluated using pilot-scale experimental data. A discounted cash flow rate of return method was used to estimate minimum selling prices (MSPs) for each product, to conduct sensitivity analyses, and to identify potential cost-reduction strategies. Using a before-finance-and-tax 16.5% nominal required return on investment, and a mean transport distance of 200 km, the estimated delivered MSPs per oven-dry metric ton (ODMT) of WCB, TWCB, and biochar were $162, $274, and $1044 respectively. The capital investment (16–30%), labor cost (23–28%), and feedstock cost (10–13%) without stumpage cost were the major factors influencing the MSP of solid biofuels and biochar. However, the MSPs of WCB, TWCB, and biochar could be reduced to $65, $145, and $470/ODMT respectively with technologically improved portable systems. In addition, the MSPs of solid biofuels and biochar could be further reduced by renewable energy and carbon credits, if the greenhouse gas (GHG) reduction potentials are quantified and remunerated. In conclusion, portable systems could be economically feasible to use forest residues and make useful products at current market prices while simultaneously reducing potential wildfires and GHG emissions. [ABSTRACT FROM AUTHOR]

Densification of thermally treated energy crops by torrefaction is required to increase the bulk density and to reduce the handling, transport, and storage cost for bioenergy applications. In this study, we investigated the densification characteristics of thermally treated energy cane and napier grass grown on marginal lands at various applied forces and binder levels. The addition of starch (0, 10, and 15%) and lignosulfonate (0, 5, and 10%) was examined to enhance the strength and durability of raw and torrefied briquettes, respectively. Although the use of starch binder relatively increased the bulk density, it did not improve the hardness and durability of untreated energy crop briquettes. The addition of 10% lignosulfonate binder increased the torrefied briquette density of up to 11% for energy cane and up to 38% for napier grass and decreased the compression energy by up to 35% for both samples. Moreover, the hardness (compressive resistance) was tripled, and the durability was relatively improved for both torrefied briquettes. The increase in applied force not only increased the bulk density but also increased the specific energy required for densification. However, there was no substantial change in hardness and durability when the compression force was increased from 15 to 20 kN for all samples. In overall, densification of thermally treated energy crops is required, and the quality of the briquettes can be improved by the use of appropriate binders for efficient handling, transport, and storage. [ABSTRACT FROM AUTHOR]

The thermal stability of cellulose nanofibrils (CNFs) can be improved by converting cellulose crystalline structure to cellulose II using an alkaline treatment method. The conventional method requires around 20 wt.% NaOH solutions and causes the cellulose interdigitation and aggregation, making CNFs production difficult. The objective of this study is to develop a new pretreatment method using a low-concentration alkaline solution to produce well-dispersed CNFs with improved thermal stability. CNFs with 90 nm diameter were successfully prepared by treating cellulose powder with 2 wt.% NaOH solution below 0 °C, followed by homogenization through a French pressure cell press. The CNFs had relatively high thermal stability with the mean onset and maximum thermal decomposition temperature of 305 °C and 343 °C, respectively, compared with the CNFs prepared without the NaOH pretreatment (283 °C and 310 °C). The increased thermal stability can create new opportunities for the development of CNF-based bio-composites and electronics. [ABSTRACT FROM AUTHOR]

We have developed a sustainable dyeing technology with nanofibrillated cellulose (NFC) fibers that would decrease the amount of water, salt and alkali used in cotton dyeing by one order of magnitude, but with comparable dyeing performance to a conventional exhaust dyeing method. [ABSTRACT FROM AUTHOR]

Torrefaction of energy sorghum and sweet sorghum bagasse was investigated at three different temperatures (250, 275 & 300 °C) for 30 min to determine product yields and its compositions. The torrefied solid yield ranged from 43% to 65% for sweet sorghum bagasse and 51–70% for energy sorghum. The energy density of both torrefied sorghums increased between 1.6 and 1.4 folds. Besides water, the acetic acid, with a maximum yield of 101.90 g L −1 was the dominant compound in the aqueous fraction of liquid products. The aqueous fraction from sweet sorghum bagasse contained furfural and furan carboxyl aldehydes, while ketones and alcohols were dominant from energy sorghum as other key compounds. Phenolic type chemicals and furan derivatives were the major compounds in the oil fraction of the liquid product, accounted up to 58 wt%. The condensable liquid products can be further upgraded into high-value platform chemicals. [ABSTRACT FROM AUTHOR]

Energy crops grown on marginal lands offer an alternative supply of renewable resources while avoiding competition with food crops and supporting feed crops. To sustainably grow energy crops, the economic and environmental impacts of various crop management practices such as the adoption of cover crops, fertilization rates, harvesting methods and its end use applications for animal feed or biofuels should be investigated. In this study, we investigated the life cycle analysis (LCA) and economic evaluation of growing two energy crops (energy cane, and napier grass) on the marginal lands with three fertilizer treatments (0, 100, and 200 kg N ha⁻¹), and with a cover crop (clover, Trifolium incarnatum L) in the southeastern United States (US). Energy crop was harvested once a year in the late fall for biofuel applications, while the Napier grass was harvested twice a year: first harvested early in spring for animal feed and later harvested in the fall for biofuel application. Experimental field data such as biomass yield, crop management practices, farm inputs, and carbon stored in the soil, were determined to assess the global warming potential and the delivered cost of each energy crop. Napier grass had lower global warming (GW) impacts and biomass delivery costs, 34–153 kg CO₂ eq. per oven-dry metric ton (ODMT) and $51–$57 perODMT, respectively than that of energy cane. However, both the energy crops provided carbon sequestrations (−17 and −232 kg CO₂ eq. ODMT⁻¹) and thus net GW impact varied between 51 and (−14) kg CO₂ eq. ODMT⁻¹ based on the treatments. When the napier grass was harvested for both biofuel and fodder applications, the overall GW impacts and the delivered costs were reduced. Therefore, energy crops can be grown in marginal lands for increased carbon sequestration while reducing the GW impacts of energy crops for biofuel production. The integrated environmental and economic analyzes further demonstrated that the energy crop delivered costs and GW impacts could be further reduced, if the energy crops can be utilized for both biofuel and feed applications. • Estimated cost and environmental impacts of producing energy crop on marginal land. • Crop management practices, including cover crop and double harvest, were evaluated. • Global warming (GW) impacts and cost of napier grass were lower than energy cane. • Among all, biomass production with cover crop had the lowest GW impacts and cost. • In napier grass, co-production of biomass and fodder reduced GW impacts and costs. [ABSTRACT FROM AUTHOR]

Mountain pine beetle (MPB) (Dendroctonus ponderosae Hopkins) has become a serious infestation problem in Western Canada. The infested lodgepole pine (Pinus concorta Douglas) becomes host to blue staining fungi and the infested trees die in 4-6 years. The dead trees gradually lose their suitability for dimension lumber and pulp chips due to excessive cracking and spoilage. Recovering the killed wood and proces- sing it to pellets for bioenergy and other applications could partially avert the economic loss, and reduce overloading of the forest floor and potential for forest fires. In this study, heating value, density, and chemical composition of pellets made from MPB-infested Pine wood were measured and compared with those measured for pellets made from uninfested pine. Chemical analysis showed minor decrease in lignin and sugar contents of pellets made from MPB wood. The mean density of pellets manufactured from MPB (about 975 kg m-3) was slightly higher than the density of pellets from uninfested wood (934 kg m-3). This difference was not statistically significant (α =0.05) due to a large variation in the measured data. The high heating value (HHV) of MBP at a mean 19.20 MJ kg-1 was not significantly different from 19.05 MJ kg-1 measured for pellets made from uninfested pine. Biologically cultured MPB pellets did not show any staining fungi growth. The overall conclusion is that MBP infested wood can be used to produce comparable pellets to non-infested wood pellets. [ABSTRACT FROM AUTHOR]

Mountain pine beetle (MPB) (Dendroctonus ponderosae Hopkins) has become a serious infestation problem in Western Canada. The infested lodgepole pine (Pinus concorta Douglas) becomes host to blue staining fungi and the infested trees die in 4-6 years. The dead trees gradually lose their suitability for dimension lumber and pulp chips due to excessive cracking and spoilage. Recovering the killed wood and processing it to pellets for bioenergy and other applications could partially avert the economic loss, and reduce overloading ofthe forest floor and potential for forest fires. In this study, heating value, density, and chemical composition ofpellets made from MPB-infested Pine wood were measured and compared with those measured for pellets made from uninfested pine. Chemical analysis showed minor decrease in lignin and sugar contents of pellets made from MPB wood. The mean density of pellets manufactured from MPB (about 975 kg m-3) was slightly higher than the density of pellets from uninfested wood (934 kg m-3).' This difference was not statistically significant (α=0.05) due to a large variation in the measured data. The high heating value (HHV) ofMBP at a mean 19.20 MJ kg-1 was not significantly different from 19.05 MJ kg-1 measured for pellets made from uninfested pine. Biologically cultured MPB pellets did not show any staining fungi growth. The overall conclusion is that MBP infested wood can be used to produce comparable pellets to noninfested wood pellets. [ABSTRACT FROM AUTHOR]

• Use of biopolymers has emerged as a new paradigm of the ecological conservation. • Biopolymers are promising sources for various applications in daily life. • Biopolymers found applications as antioxidants and antimicrobials. • Biopolymers can replace synthetics without much adverse effects. • Further understanding on their mode of action will help explore them further. Biopolymers have generated mounting interest among researchers and industrialists over the recent past. Rising consciousness on the use of eco-friendly materials as green alternatives for fossil-based biopolymers has shifted the research focus towards biopolymers. Advances in technologies have opened up new windows of opportunities to explore the potential of biopolymers. In this context, this review presents a critique on applications of biopolymers in relation to antioxidant and antimicrobial activities. Some biopolymers are reported to contain inherent antioxidant and antimicrobial properties, whereas, some biopolymers, which do not possess such inherent properties, are used as carriers for other biopolymers or additives having these properties. Modifications are often performed in order to improve the properties of biopolymers to suit them for different applications. This review aims at presenting an overview on recent advances in the use of biopolymers with special reference to their antioxidant and antimicrobial applications in various fields. [ABSTRACT FROM AUTHOR]

Climate change induced by greenhouse gas emissions from the extraction and use of fossil fuels has raised global concerns and needs to develop alternative and environmentally friendly transportation fuels from biomass and other organic carbon sources. In this study, a cradle to grave attributional life cycle assessment (LCA) was conducted to produce drop-in renewable diesel from biogas (via solid-state anaerobic digestion) derived from energy crop, i.e. miscanthus cultivated in strip-mined lands. The analysis included miscanthus cultivation, harvesting, and transportation to the biorefinery, conversion of the biomass to Fischer-Tropsch diesel, and combustion of the drop-in renewable diesel for a passenger vehicle. Results showed that the miscanthus derived drop-in renewable diesel could reduce greenhouse gas emissions by up to 73% when compared with that of the conventional fossil-derived diesel. Similarly, the proposed design consumes 4.91 MJ/GGE of fossil fuel compared to the conventional diesel with fossil fuel depletion of 18.98 MJ/GGE. Although the respiratory effects, smog formation, acidification, and eutrophication potentials of the miscanthus to drop-in renewable diesel process are relatively higher than the conventional process, the proposed technology still represents a sustainable liquid fuels pathway that is less dependent on fossil fuel, can substantially reduce greenhouse gas emissions, and help attain the renewable transportation fuels standard. Image 1 • Renewable diesel derived from miscanthus by anaerobic digestion and F-T synthesis. • GHG emissions of renewable diesel reduced by 73% when displacing fossil diesel. • Use of digestate as chemical fertilizer further reduced the GHG emissions by 24%. • Renewable diesel qualifies for the U.S. Renewable Fuel Standard credits. • Ten other environmental impacts of renewable diesel compared with fossil diesel. [ABSTRACT FROM AUTHOR]