Pipeline transport of biomass

The cost of transporting wood chips by truck and by pipeline as a water slurry was determined. In a practical application of field delivery by truck of biomass to a pipeline inlet, the pipeline will only be economical at large capacity (>0.5 million dry t/yr for a one-way pipeline, and >1.25 million dry t/yr for a two-way pipeline that returns the carrier fluid to the pipeline inlet), and at medium to long distances (>75 km [one-way] and >470 km [two-way] at a capacity of 2 million dry t/yr). Mixed hardwood and softwood chips in western Canada rise in moisture level from about 50% to 67% when transported in water; the loss in lower heating value (LHV) would preclude the use of water slurry pipelines for direct combustion applications. The same chips, when transported in a heavy gas oil, take up as much as 50% oil by weight and result in a fuel that is >30% oil on mass basis and is about two-thirds oil on a thermal basis. Uptake of water by straw during slurry transport is so extreme that it has effectively no LHV. Pipeline-delivered biomass could be used in processes that do not produce contained water as a vapor, such as supercritical water gasification.     

Thermal processing of algal biomass for biofuel production

Concerns over the environment and energy security have led to considerable research efforts into the development of renewable alternatives to fossil-based fuels and chemical from biomass. Algae has been identified as the biomass with great potential for utilization in this regard, due to several advantages algae has over terrestrial plants, such as a higher growth rate and photosynthetic efficiency, better CO₂ sequestration, and the ability to grow in non-arable land with low quality water. Conversion technologies, particularly thermochemical conversion, are actively being researched and developed to produce renewable chemicals and fuels. A major advance in this regard is thermal conversion of whole algal biomass, especially wet processing that can significantly reduce the cost of production. This short review looks at major developments in thermal processing of algal biomass with primary focus on the past two years.     

Canadian biomass reserves for biorefining

A lignocellulosic-based biorefining strategy may be supported by biomass reserves, created initially with residues from wood product processing or agriculture. Biomass reserves might be expanded using innovative management techniques that reduce vulnerability of feedstock in the forest products or agricultural supply chain. Forest-harvest residue removal, disturbance isolation, and precommercial thinnings might produce 20–33×10⁶ mt/yr of feedstock for Canadian biorefineries. Energy plantations on marginal Canadian farmland might produce another 9–20 mt. Biomass reserves should be used to support first-generation biorefining installations for bioethanol production, development of which will lead to the creation of future high-value coproducts. Suggestions for Canadian policy reform to support biomass reserves are provided.     

Financial and energy costs of supplying woody biomass to conversion sites

A series of short rotationPopulus plantations involving four management strategies were evaluated in tandem with alternate harvest and storage strategies to determine the least cost method for supplying biomass to conversion sites. All inputs were itemized on both a financial and energy basis to establish the unit output costs for commercial-scale systems. The control strategy had the lowest production costs, at $28.74 Mg^-1 (ovendry), and 5,455 MJ Mg^-1(OD). The addition of harvest and storage costs, based on existing and proposed technologies within the forest product industries, increased the total supply cost for biomass to $59.61 Mg^-1(OD) and 7,233.1 MJ Mg^-1(OD). On a financial basis, the proposed cost was 17% more expensive than a projected price for biomass from an ethanol plant and was also higher than the general prices for aspen from domestic markets. However, on an energy basis, the gross heat of combustion for thePopulus biomass was 2.7 times greater than its total energy costs.     

Large-scale ethanol fermentation through pipeline delivery of biomass

Issues of traffic congestion and community acceptance limit the size of biomass-processing plants based on truck delivery to about 2 million (M) dry t/yr or less. In this study, the cost of ethanol from an ethanol fermentation plant processing 2 M dry t/yr of corn stover supplied by truck is compared with that of larger plants in the range of 4–38 M dry t/yr supplied by a combination of trucks plus pipelines. For corn stover, a biomass source with a low yield per gross hectare, the cost of ethanol from larger plants is always higher. For wood chips from the boreal forest, a biomass source with a relatively high yield per gross hectare, a plant processing 14–38 M dry t/yr produces ethanol at a 13% reduction in cost compared with a plant producing 2 M dry t/yr supplied by truck. Processing of value-added products, such as chemicals from lignin, would be enabled by larger-scale plants.     

Effect of operating conditions on biomass growth during citric acid production by solid-state fermentation

The effect of aeration, agitation, and bed loading on biomass and product concentration during citric acid biosynthesis by solid-state fermentation was investigated. For this purpose, Aspergillus niger S was cultivated on sugar beet pulp in a 4.5 dm³ horizontal rotating drum bioreactor. The results suggest that the parameters examined have a remarkable effect on the quantity of biomass being formed and on the product concentration. The maximum citric acid production (about 150 g per kg of the substrate dry matter) was obtained under the following conditions: aeration rate 0.2 dm³ kg⁻¹ min⁻¹, mixing (periodical) 1 min once an hour, and bed loading 30 % of the bioreactor working volume. However, these values did not favour biomass formation. Moreover, it was found that accumulation of the product reached its maximum when the amount of biomass was minimal (approximately 252-29 g per kg of the substrate dry matter) under the conditions involved. Presented at the 34th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 21–25 May 2007.     

Thermal study of decomposition of selected biomass samples

Fears of climate change and increasing concern over the global warming have prompted a search for new, cleaner methods for electricity power generation. Technologies based on utilising biomass are attracting much attention because biomass is considered to be CO₂ neutral. Co-firing of biomass fuels with coal, for example, is presently being considered as a mean for reducing the global CO₂ emissions. Biomass is also applied in thermal conversion processes to produce fuels with higher calorific values and adsorbents. In any case, thermal decomposition is essential stage where volatiles and tars are evolved followed by consequent heats of reactions. In this work sawdust biomass samples were selected in order to study their thermal conversion behaviour. Heats of decomposition for each sample were measured during continuous heating at a prescribed heating rate under inert atmospheric conditions. The decomposition generally commenced in all samples at 150°C and was completed at 460°C in a series of endo and exothermic reactions influenced by its lignin and cellulosic content. Single biomass sample was subjected to heating rates ranging from 10 to 1000°C min^-1 and the effect of heating rate on decomposition was studied. The origin of reactions for each thermal sequence is herein discussed in detail. This revised version was published online in July 2006 with corrections to the Cover Date.     

Corn stover availability for biomass conversion: situation analysis

As biorefining conversion technologies become commercial, feedstock availability, supply system logistics, and biomass material attributes are emerging as major barriers to the availability of corn stover for biorefining. While systems do exist to supply corn stover as feedstock to biorefining facilities, stover material attributes affecting physical deconstruction, such as densification and post-harvest material stability, challenge the cost-effectiveness of present-day feedstock logistics systems. In addition, the material characteristics of corn stover create barriers with any supply system design in terms of equipment capacity/efficiency, dry matter loss, and capital use efficiency. However, analysis of a conventional large square bale corn stover feedstock supply system concludes that (1) where other agronomic factors are not limiting, corn stover can be accessed and supplied to a biorefinery using existing bale-based technologies, (2) technologies and new supply system designs are necessary to overcome biomass bulk density and moisture material property challenges, and (3) major opportunities to improve conventional bale biomass feedstock supply systems include improvements in equipment efficiency and capacity and reducing biomass losses in harvesting, collection, and storage. Finally, the backbone of an effective stover supply system design is the optimization of intended and minimization of unintended material property changes as the corn stover passes through the individual supply system processes from the field to the biorefinery conversion processes.

Macroscopic mass and energy balance of a pilot plant anaerobic bioreactor operated under thermophilic conditions

Intensive poultry production generates over 100,000 t of litter annually in West Virginia and 9×10⁶ t nationwide. Current available technological alternatives based on thermophilic anaerobic digestion for residuals treatment are diverse. A modification of the typical continuous stirred tank reactor is a promising process being relatively stable and owing to its capability to manage considerable amounts of residuals at low operational cost. A 40-m³ pilot plant digester was used for performance evaluation considering energy input and methane production. Results suggest some changes to the pilot plant configuration are necessary to reduce power consumption although maximizing biodigester performance.     

Upconversion Luminescence in Mononuclear Yb/Sm Co-crystal Assemblies at Room Temperature

Metal-based upconversion luminescence transforming high-energy photons into low-energy photons is an attractive anti-Stokes shift process for fundamental research and promising applications. In this work, we developed the upconversion luminescence in co-crystal assemblies consisting of discrete mononuclear Yb and Sm complexes. The characteristic visible emissions of Sm³⁺ were observed under the excitation of absorption band of Yb³⁺ at 980 nm. A series of co-crystal assemblies were investigated based on mononuclear Yb and Sm complexes, and the strongest luminescence was obtained when the molar concentration between Yb³⁺ and Sm³⁺ is equivalent. The crystal structure was fully characterized by the single crystal X-ray diffraction and upconverting energy transfer mechanisms were verified as cooperative sensitization upconversion and energy transfer upconversion. This is the first example of Sm³⁺-based upconverting luminescence in discrete lanthanide complexes which present as co-crystal assemblies at room temperature.     

Cd(II) and Pb(II) extraction and transport modeling in SLM and PIM systems using Kelex 100 as carrier

The extraction and transport of Cd(II) and Pb(II) in two different membrane systems (SLM and PIM) using Kelex 100 as carrier was studied, proposing the corresponding chemical models of transport. A two-species transport model is proposed for Cd(II), according to solvent extraction (SX) data. Experimental SLM permeabilities are 9.7×10⁻⁵ m s⁻¹, while measured PIM permeabilities are 5×10⁻⁵ m s⁻¹. Values for the aqueous boundary layer thickness and for the diffusion coefficient of the metal cation-carrier complexes in the membrane phase were calculated from numerical fitting of experimental data using the proposed transport models. A highly selective Pb(II) separation was achieved in PIM systems based on the nature of the chemical equilibria involved in Cd(II) and Pb(II) membrane transport.     

Estimating emissions of HCFC-22 and CFC-11 in China by atmospheric observations and inverse modeling

This paper presents the estimation of Chinese emissions of HCFC-22 and CFC-11 in 2009 by an inverse modeling method based on in-situ measurement data from the Shangdianzi Global Atmosphere Watch (GAW) Regional Station (SDZ) and atmospheric transport simulations. After inversion (a-posteriori) estimates of the Chinese emissions in 2009 increased by 6.6% for HCFC-22 from 91.7 (± 83.6) to 98.3 (± 47.4) kt/yr and by 22.5% for CFC-11 from 13 (±12.6) to 15.8 (±7.2) kt/yr compared to an a-priori emission. While the model simulation with a-priori emissions already captured the main features of the observed variability at the measurement site, the model performance (in terms of correlation and mean-square-error) improved using a-posteriori emissions. The inversion reduced the root-mean-square (RMS) error by 4% and 10% for HCFC-22 and CFC-11, respectively.     

细胞工厂与生物炼制

生物炼制是以可再生生物质资源为原料,生产能源与化工产品的新兴工业模式.是转变经济增长模式,保障社会经济可持续发展的重大战略需求.微生物细胞工厂是生物炼制技术至关重要的核心.世界各国纷纷设立重大研究计划支持细胞工厂的研究,以期获得生物炼制技术的领先地位.本文简要概括了细胞工厂和生物炼制这一新兴工业模式,回顾了生物炼制细胞工厂的重大计划和进展,讨论了目前亟待解决的关键问题和研究对策.     

Swine Manure-Based Pilot-Scale Algal Biomass Production System for Fuel Production and Wastewater Treatment—a Case Study

Integration of wastewater treatment with algae cultivation is one of the promising ways to achieve an economically viable and environmentally sustainable algal biofuel production on a commercial scale. This study focused on pilot-scale algal biomass production system development, cultivation process optimization, and integration with swine manure wastewater treatment. The areal algal biomass productivity for the cultivation system that we developed ranged from 8.08 to 14.59 and 19.15–23.19 g/m²?×?day, based on ash-free dry weight and total suspended solid (TSS), respectively, which were higher than or comparable with those in literature. The harvested algal biomass had lipid content about 1.77–3.55 %, which was relatively low, but could be converted to bio-oil via fast microwave-assisted pyrolysis system developed in our lab. The lipids in the harvested algal biomass had a significantly higher percentage of total unsaturated fatty acids than those grown in lab conditions, which may be attributed to the observed temperature and light fluctuations. The nutrient removal rate was highly correlated to the biomass productivity. The NH₃-N, TN, COD, and PO₄-P reduction rates for the north-located photo-bioreactor (PBR-N) in July were 2.65, 3.19, 7.21, and 0.067 g/m²?×?day, respectively, which were higher than those in other studies. The cultivation system had advantages of high mixotrophic growth rate, low operating cost, as well as reduced land footprint due to the stacked-tray bioreactor design used in the study.     

Photoexcited Carrier Transfer in CuInS2 Nanocrystal Assembly by Suppressing Resonant-Energy Transfer

High-density assemblies or superlattice structures composed of colloidal semiconductor nanocrystals have attracted attention as key materials for next-generation photoelectric conversion devices such as quantum-dot solar cells. In these nanocrystal solids, unique transport and optical phenomena occur due to quantum coupling of localized energy states, charge-carrier hopping, and electromagnetic interactions among closely arranged nanocrystals. In particular, the photoexcited carrier dynamics in nanocrystal solids is important because it significantly affects various device parameters. In this study, we report the photoexcited carrier dynamics in a solid film of CuInS₂ nanocrystals, which is one of the potential nontoxic substitutes with Cd- and Pb-free compositions. Meanwhile, these subjects have been extensively studied in nanocrystal solids formed by CdSe and PbS systems. A carrier-hopping mechanism was confirmed using temperature-dependent photoluminescence spectroscopy, which yielded a typical value of the photoexcited carrier-transfer rate of (2.2±0.6)×10⁷ s⁻¹ by suppressing the influence of the excitation-energy transfer.     

High‐Performance Liquid‐Catalyst Fuel Cell for Direct Biomass‐into‐Electricity Conversion

Herein, we report high‐performance fuel cells that are catalyzed solely by polyoxometalate (POM) solution without any solid metal or metal oxide. The novel design of the liquid‐catalyst fuel cells (LCFC) changes the traditional gas–solid‐surface heterogeneous reactions to liquid‐catalysis reactions. With this design, raw biomasses, such as cellulose, starch, and even grass or wood powders can be directly converted into electricity. The power densities of the fuel cell with switchgrass (dry powder) and bush allamanda (freshly collected) are 44 mW cm^?2 and 51 mW cm^?2 respectively. For the cellulose‐based biomass fuel cell, the power density is almost 3000 times higher than that of cellulose‐based microbial fuel cells. Unlike noble‐metal catalysts, POMs are tolerant to most organic and inorganic contaminants. Therefore, almost any raw biomass can be used directly to produce electricity without prior purification.     

细胞工厂与生物炼制

生物炼制是以可再生生物质资源为原料,生产能源与化工产品的新兴工业模式。是转变经济增长模式,保障社会经济可持续发展的重大战略需求。微生物细胞工厂是生物炼制技术至关重要的核心。世界各国纷纷设立重大研究计划支持细胞工厂的研究,以期获得生物炼制技术的领先地位。本文简要概括了细胞工厂和生物炼制这一新兴工业模式,回顾了生物炼制细胞工厂的重大计划和进展,讨论了目前亟待解决的关键问题和研究对策。     

Oxidative lime pretreatment of high-lignin biomass

Lime (Ca[OH]₂) and oxygen (O₂) were used to enhance the enzymatic digestibility of two kinds of high-lignin biomass: poplar wood and newspaper. The recommended pretreatment conditions for poplar wood are 150°C, 6 h, 0.1 g of Ca(OH)₂/g of dry biomass, 9 mL of water/g of dry biomass, 14.0 bar absolute oxygen, and a particle size of −10 mesh. Under these conditions, the 3-d reducing sugar yield of poplar wood using a cellulase loading of 5 filter paper units (FPU)/g of raw dry biomass increased from 62 to 565 mg of eq. glucose/g of raw dry biomass, and the 3-d total sugar (glucose + xylose) conversion increased from 6 to 77% of raw total sugars. At high cellulase loadings (e.g., 75 FPU/g of raw dry biomass), the 3-d total sugar conversion reached 97%. In a trial run with newspaper, using conditions of 140°C, 3 h, 0.3 g of Ca(OH)₂/g of dry biomass, 16 mL of water/g of dry biomass, and 7.1 bar absolute oxygen, the 3-d reducing sugar yield using a cellulase loading of 5 FPU/g of raw dry biomass increased from 240 to 565 mg of eq. glucose/g of raw dry biomass. A material balance study on poplar wood shows that oxidative lime pretreatment solubilized 38% of total biomass, including 78% of lignin and 49% of xylan; no glucan was removed. Ash increased because calcium was incorporated into biomass during the pretreatment. After oxidative lime pretreatment, about 21% of added lime could be recovered by CO₂ carbonation.     

The N&P Co-doped Lotus Root Derived Carbon Materials for Highly Sensitive Electrochemical Analysis of Baicalein and Luteolin

The application of biomass-based carbon materials in electrochemical sensing was limited due to their few active sites. So N and P double doped biomass pyrolytic carbon materials were designed in this paper. These gained materials were characterized by a series of characterization test techniques, and used as electrode modification to construct electrochemical sensors to detect baicalein (BA) and luteolin (LU). Under the best test condition, the minimum detectability of BA and LU was (7.8±0.25)×10⁻⁹ mol/L and (7.6±0.24)×10⁻⁹ mol/L (S/N=3), respectively. And the sensor performed well in the Shuanghuanglian oral liquid and the healthy human urine samples.     

Tetrathiafulvalene‐Fused Porphyrins via Quinoxaline Linkers: Symmetric and Asymmetric Donor–Acceptor Systems

A tetrathiafulvalene (TTF) donor is annulated to porphyrins (P) via quinoxaline linkers to form novel symmetric P–TTF–P triads 1 a – c and asymmetric P–TTF dyads 2 a , b in good yields. These planar and extended π‐conjugated molecules absorb light over a wide region of the UV/Vis spectrum as a result of additional charge‐transfer excitations within the donor–acceptor assemblies. Quantum‐chemical calculations elucidate the nature of the electronically excited states. The compounds are electrochemically amphoteric and primarily exhibit low oxidation potentials. Cyclic voltammetric and spectroelectrochemical studies allow differentiation between the TTF and porphyrin sites with respect to the multiple redox processes occurring within these molecular assemblies. Transient absorption measurements give insight into the excited‐state events and deliver corresponding kinetic data. Femtosecond transient absorption spectra in benzonitrile may suggest the occurrence of fast charge separation from TTF to porphyrin in dyads 2 a , b but not in triads 1 a – c . Clear evidence for a photoinduced and relatively long lived charge‐separated state (385 ps lifetime) is obtained for a supramolecular coordination compound built from the ZnP–TTF dyad and a pyridine‐functionalized C₆₀ acceptor unit. This specific excited state results in a (ZnP–TTF)^?+ ??? (C₆₀py)^?? state. The binding constant of Zn^II ??? py is evaluated by constructing a Benesi–Hildebrand plot based on fluorescence data. This plot yields a binding constant K of 7.20×10⁴ M ^?1, which is remarkably high for bonding of pyridine to ZnP.