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Electricity generation integrated with xylose degradation was investigated in a two-chamber mediator-less microbial fuel cell (MFC). Voltage output followed saturation kinetics as a function of xylose concentration for concentration below 9.7 mM, with a predicted maximum of 86 mV (6.3 mW m(-2) or 116 mW m(-3)) and half-saturation constant (K(s)) of 0.29 mM. Xylose concentrations from 0.5 mM to 1.5 mM resulted in coulombic efficiencies and maximum voltage ranging from 41+/-1.6% to 36+/-1.2% and 55+/-2.0 mV to 70+/-3.0 mV respectively. Xylose degradation rate increased with increasing xylose concentration up to 9.7 mM and the predicted maximum degradation rate was 0.13 mM h(-1) and K(s) of 3.0 mM. Stirring by nitrogen in the anode chamber led to 99+/-2.3 mV maximum voltage (8.4+/-0.4 mW m(-2) or 153+/-7.1 mW m(-3)) and 5.9+/-0.3% coulombic efficiency at MFC running time 180 h, which were respectively 17+/-1.2% and 37+/-1.8%, higher than those without stirring. The COD removal under stirring was 22.1+/-0.3%, which was slightly lower than that of 23.7+/-0.4% under no stirring. However, stirring resulted in 59% lower xylose degradation rate. This work demonstrates that xylose can be used in the MFC for electricity production. Comparatively higher electricity generation and coulombic efficiency can be obtained by adjusting initial xylose concentration and applying stirring in the anode chamber.

The effect of substrate changes on the performance and microbial community of two-chamber microbial fuel cells (MFCs) was investigated in this study. The MFCs enriched with a single substrate (e.g., acetate, glucose, or butyrate) had different acclimatization capability to substrate changes. The MFC enriched with glucose showed rapid and higher power generation, when glucose was switched with acetate or butyrate. However, the MFC enriched with acetate needed a longer adaptation time for utilizing glucose. Microbial community was also changed when the substrate was changed. Clostridium and Bacilli of phylum Firmicutes were detected in acetate-enriched MFCs after switching to glucose. By contrast, Firmicutes completely disappeared and Geobacter-like species were specifically enriched in glucose-enriched MFCs after feeding acetate to the reactor. This study further suggests that the type of substrate fed to MFC is a very important parameter for reactor performance and microbial community, and significantly affects power generation in MFCs.

The energy efficiency of microwave-assisted dilute sulfuric acid pretreatment of rape straw for the production of ethanol was investigated. Different microwave energy inputs and solid loadings were tested to find economic pretreatment conditions. The lowest energy consumption was observed when solid loading and energy input were fixed at 50% (w/w) and 54 kJ (900 W for 1 min), respectively, and amounted to 5.5 and 10.9 kJ to produce 1g of glucose after enzymatic hydrolysis and 1g ethanol after fermentation, respectively. In general, 1g ethanol can produce about 30 kJ of energy, and therefore, the energy input for the pretreatment was only 35% of the energy output. The approach developed in this study resulted in 92.9% higher energy savings for producing 1g ethanol when compared with the results of microwave pretreatments previously reported.

Fusarium oxysporum F3 alone or in mixed culture with Saccharomyces cerevisiae F12 were used to ferment carbohydrates of wet exploded pre-treated wheat straw (PWS) directly to ethanol. Both microorganisms were first grown aerobically to produce cell mass and thereafter fermented PWS to ethanol under anaerobic conditions. During fermentation, soluble and insoluble carbohydrates were hydrolysed by the lignocellulolytic system of F. oxysporum. Mixed substrate fermentation using PWS and corn cobs (CC) in the ratio 1:2 was used to obtain an enzyme mixture with high cellulolytic and hemicellulolytic activities. Under these conditions, activities as high as 34300, 9100, 326, 24, 169, 27 and 254 U dm(-3) of xylanase, endoglucanase, beta-glucosidase, arabinofuranosidase, avicelase, feruloyl esterase and acetyl esterase, respectively, were obtained. The replacement of the enzyme production phase of F. oxysporum by the addition of commercially available enzymes Celluclast (R) 1.5 L FG and Novozym (R) 188 in 3:1 ratio for the treatment of PWS, resulted in a 3-fold increase in the volumetric ethanol productivity without increasing the ethanol production significantly. By direct bioconversion of 110 kg m(-3) dry matter of PWS, ethanol concentration (4.9 kg m(-3)) and yield (40 g kg(-1) of PWS) were similarly obtained by F. oxysporum and the mixed culture, while productivity rates as high as 34 g m(-3) h(-1) and 108 g m(-3) h(-1) were obtained by F. oxysporum and the mixed culture, respectively.

The environmental profile of two municipal solid waste incineration (MSWI) technologies with semi-dry flue gas cleaning, namely grated firing incinerators (GFI) and fluidised bed incinerators (FBI) that are commonly used in China were evaluated and compared by life-cycle assessment (LCA) using the EASEWASTE model. All emissions of key pollutants as well as energy, resource and material inputs and outputs associated with the two MSWI technologies were determined and the corresponding environmental impact potentials were modelled. Incineration of MSW with a lower heating value (LHV) around 4.5 MJ kg—1 demands that auxiliary fuel is used, and both GFI and FBI caused environmental loads by contributing with environmental impact potentials in most categories except for some saving in global warming (GW100) and hazardous waste (HW). Coal combustion in FBI is a main contributor to the environmental impact potentials and thus should always be limited to a minimum. Auxiliary fuels can be avoided when the LHV of MSW is higher than 5—6 MJ kg— 1. For all scenarios, GFI saves more global warming potentials than FBI due to its higher net power generation from combustion of MSW itself. Leachate from the bunker could be sprayed into the furnace for evaporation under high temperature, as an alternative to waste-water treatment, without major changes in the environmental profile of the incinerator. The presented evaluations may contribute to a more balanced environmental assessment of the two incineration technologies with respect to incineration of MSW with low heating values as often found in Asia and China.

AbstractThe property of a variety of ionic liquids (ILs) as reaction media was evaluated for the production of biodiesel by enzymatic methanolysis of rapeseed oil. The IL Ammoeng 102, containing tetraaminum cation with C18 acyl and oligoethyleneglycol units, was found to be capable of forming oil/IL biphasic reaction system by mixing with substrates, which is highly effective for the production of biodiesel with more than 98% biodiesel yield and nearly 100% conversion of oil. Conductor‐like screening model for real solvent (COSMO‐RS) in silico prediction of substrate solubility and simulation of partition coefficient change vs. reaction evolution indicated that the amphiphilic property of Ammoeng 102 might be responsible for creating efficient interaction of immiscible substrates; while big difference of partition coefficients of generated biodiesel and glycerol between the two phases suggests a large chemical potential to move reaction equilibrium for maximum oil conversion and yield of target biodiesel. The reaction behavior and specificity of oil/IL biphasic system for enzymatic production of biodiesel were theoretically delineated through COSMO‐RS computation with experimental validation. © 2010 American Institute of Chemical Engineers AIChE J, 2011

This paper reports the large scale bilateral development program- the Danish-Chinese Wind Energy Development Program (WED). The paper starts with overview of electric energy production and consumption in the two counties with special focus on wind energy status. Next, the detailed objectives, organization, tasks and plan and latest progress of the WED project are described. Finally, the conclusion and future scope of the WED are presented.

This paper proposes a stochastic time-series based method to simulate the volatility of intermittent renewable generation and distributed storage devices along timeline. The proposed method can calculate the optimal timeline for different electricity markets and power systems. In practice, the proposed method is potentially useful for designing market rules and evaluating different design options. Following works is underway on application and simulation of proposed method using the realistic distribution system of Bornholm Island in Denmark.