Advanced Materials Research Vols. 860-863

Abstract: Abstract. The feature change of corn stover and sugar concentration have been studied during it being enzymatic hydrolyzed. The feature change of corn stover during enzyme hydrolysis process is analyzed by the biological microscope and scanning electron microscopy. The sugar concentration is tested by ultraviolet and visible spectrophotometer. The sugar concentration is obvious rising in enzyme hydrolysis 1h and will keep rising during the whole enzyme hydrolysis process. The reducing concentration of 15%(w/w) corn stover steam explosion is 57.5g/L. Fibrous grain size gradually decreases and its quantity also reduces in enzyme hydrolysis process. Globular solid particles significantly increase in enzyme hydrolysis 48 h. The shapes of corn stover steam explosion are mainly fibrous. But there are a lot of slivers and cracks on the fiber surface, the fiber bundles are separated, and there are some cavity structures. Fiber is gradually broken into small particles, the particles internal cavity further increase, but the splitting and crack quantity decreases in enzyme hydrolysis 12 h. However, in enzyme hydrolysis 48 h, the internal cavities of the grains increase, and the quantity of slivers and cracks also increase, which shows that that parts of the crystallization cellulose are catalyzed into soluble glucose by enzyme in later enzyme hydrolysis reaction stage.

Abstract: For biomass gasification, the high tar and carbon monoxide contents and the low heat value of fuel gas are problems to be solved, which leading to the poor operating conditions of the completed projects in China. Therefore, a new technology of biomass oxygen-enriched gasification in pressurized fluidized bed is proposed. Coupling the technologies of pressurized biomass oxygen-enriched gasification at low temperature, high-temperature gasification and melting, steam reforming and hydrocarbon synthesis, the high gasification efficiency, tar cracking and gas reforming shall be realized, and the middle/high heat value gas which meets the national standards will be produced. ASPEN PLUS simulation was carried out for biomass oxygen-enriched gasification. Both the equivalent ratio and gas yield of rice husk are lower than that of the wood sawdust, while the gas calorific values are equivalent. Considering the gas yield, the calorific value and economy, the optimum operating conditions are obtained: the gasification temperature at 1200 °C, the oxygen purity at 0.9, the equivalent ratio at about 0.25, the S/B ratio at 0.1~0.2. The gas yield could reach 1.9 m³/kg, and the gas calorific value was above 11 MJ/m³.

Abstract: Microbial fuel cells (MFCs) have been paid much attention due to its clean and renewable energy. In recent years, MFCs performed without addition of mediator were reported. In this research, the gene expression of atpI involved in ATP synthase of energy metabolism was compared at 3.7 and 37 mV applied voltage by reverse-transcription PCR. At high applied voltage, gene expression of atpI caused a 11.6-fold increase more than that at low applied voltage. Accordingly, overexpression vector harboring atpI gene was further constructed to demonstrate the effect of ATP synthase on the electricity production in MFC. The result showed that the current generated by E. coli harboring atpI gene can efficiently and rapidly be enhanced. The current production with atpI gene overexpression in E. coli was 3-fold higher than that of only pET15b vector at 106^th h. Consequently, these results verified that electricity production can be improved via introduction of energy metabolism gene without addition of mediator. Keywords: Microbial fuel cells, atpI, gene expression,electricity

Abstract: In an effort to direction convert biomass by means of pyrolysis for fine chemicals as a substitute fuel, some inorganic matters were chosen to investigate the possibility of improving the catalysis of biomass pyrolysis. Inorganic acids are catalysts to be found effective for giving high selectivity to furfural chemicals.

Abstract: Microbial fuel cell (MFC) provides a new opportunity for the sustainable production of energy from the textile wastewater. However, limited studies revealed the high electricity generation using a single-chambered MFC in treating crystal violet (CV) containing wastewater. This study isolated an exoelectrogen Aeromonas hydrophila YC 57, inoculated to a single-chambered MFC and intended to achieve a high power output. The results showed that the removal efficiency of CV and coulombic efficiency of MFC by A. hydrophila YC 57 were achieved at 82.5±0.7% and 57.2±0.5% at initial CV concentration of 100 mg/L, respectively. The maximum power generation of MFC was 240±5.6 mW/m². Results of cyclic voltammogram hinted the intermediate products of CV dye played roles of mediators. Toxicity studies revealed that metabolites of CV produced by A. hydrophila YC 57 were nontoxic. To our knowledge, this is the first time to demonstrate the electricity characteristics of a single-chambered MFC inoculated A. hydrophila YC 57.

Abstract: Thermo-chemical conversion to prepare biomass liquid fuel is one of the most promising biomass utilization technologies for biomass energy. Direct liquefaction and indirect liquefaction, two main thermo-chemical conversion technologies for liquid fuel from biomass were introduced in detail. Moreover, the latest research status of five kinds of liquid-fuel products from biomass by thermo-chemical conversion technology, such as methanol, ethanol, dimethyl ether, biodiesel and biomass pyrolytic oil were especially discussed. In addition, the problems existing in the thermo-chemical conversion technology and products are discussed and the developing trend and some proposals on thermo-chemical utilization of biomass energy in future are p resented.

Abstract: In this study, thermogravimetric analysis and kinetic analysis techniques were used to investigating the pyrolysis characteristic of the eucalyptus feedstock sourced from South China. The thermogravimetric analysis results indicate that the pyrolysis of eucalyptus sample occurred in three main stages which are the moisture vaporization stage, the volatile matter release stage and the char decomposition stage. The kinetic analysis results show that C-R kinetic method fits to the pyrolysis characterizations of eucalyptus. In addition, the effects of different constant heating rates on the pyrolysis behavior and kinetic parameters have been also studied in this paper.

Abstract: The conversion of cellulose under the hydrothermal condition was studied in an autoclave reactor. The reaction factors, such as oxygen supply and alkaline concentration was clearly investigated. A highest formic acid yield of about 27% was obtained. And also, other organic acid production was greatly produced. Besides formic acid, glycolic acid, acetic acid and lactic acid were also produced in alkaline oxidation of cellulose, with a total organic acid of up to 50%. It shows great potential for organic acid production from hydrothermal oxidation of cellulose.

Abstract: Eighty-four, 61 and 105 groundnut seeds, including high oleate genotypes and F₂ seeds of normal oleate × high oleate crosses, genotypes with high or low oil and F₂ seeds from high oil × low oil crosses, and randomly selected samples representing various origins, different seed sizes, and varied seed coat color and protein content, were used to develop the NIRS models for main fatty acids, oil and protein. For oleic, linoleic and palmitic acid, the optimized spectrum pretreatment method was first derivative plus multiplicative scattering correction; for stearic acid and the four bad fatty acids, first derivative plus vector normalization. The R_cal² and RMSECV for oleic acid were 97.20% and 2.65%; for linoleic acid, 96.90% and 2.40%; and for palmitic acid, 93.39% and 0.53%, respectively. The best spectrum pretreatment method for oil and protein was first derivative plus multiplicative scattering correction and min-max normalization. For oil and protein, the R_cal² was 89.06% and 91.45%, and RMSECV, 0.89% and 0.78%, respectively. The NIRS models can be used to develop groundnut cultivars both with high oil and with high oleate to cater the growing need for biodiesel production.

Abstract: In this paper, hydrothermal conversion of cellulose into organic acids in the presence of metal oxides was investigated. The results showed metal oxides could enhance the conversion of cellulose into organic acids. The total yields of organic acids of 41.6% with Al₂O₃ 2.0 mmol from cellulose was achieved at 300 oC for 1 min, NaOH 2.5 M and water 2 mL. The plausible mechanism for the hydrothermal conversion of cellulose into organic acids was also discussed.