Advanced Materials Research Vols. 550-553

Abstract: Ethanol production from lignocellulosic materials provides an alternative energy production system. Dilute sulfuric acid pretreatment of corn straw and rice straw and enzymatic hydrolysis of cellulose were investigated in this study. The straw was pretreated at 121°C with different sulfuric acid concentrations (1, 2, 3, 4and 5%, v/v) and residence times (30, 60, and 90 min). The concentration and conversion of total reducing sugars were analyzed. Pretreatment residence time play a key role in increase glucose concentration comparing to sulfuric acid concentration. Cellulose remaining in the pretreated feedstock was highly digestible by cellulases from Trichoderma viride. The result that the saccharification yield of 72.38% and 82.84% from corn straw and rice straw by using 2% (v/v) acid pretreatment at 121°C for 60 min and saccharifying with cellulase preparations.

Abstract: This study focuses on kinetics of straw hydrolysis using sulfuric acid catalyst to produce fermentable sugars. The result shows the degradation of sugars is encountered during the hydrolysis of straw biomass. A consecutive first-order reactions kinetic model is proposed and the kinetic model well agrees with the experimental data. It turns out that rate of sugar formation and degradation is small at lower experimental temperature. The reactions rates constant k1 including the formation of sugar begins to increase rapidly when the Fe²⁺ concentration increases from 0.125 to 0.500molL-1. However, the rate constant k2 relevant with the degradation of sugar varies unsensibly below 0.375molL-1 Fe²⁺ and it is accelerated as the Fe²⁺ concentration increases to 0.500molL-1. Thus the optimum yield is obtained at 0.375molL-1 Fe²⁺ concentration.

Abstract: Malaysian limestone modified with and additions of transition metal promoters (Ni, Fe, and Co) were used for gasification of biomass. The effects of selected metal oxide loading and the addition of sodium carbonate, Na₂CO₃ as additive and its influence on limestone catalytic activity during gasification for hydrogen conversion were investigated. The catalysts were synthesized through deposition-precipitation (DP) method and characterized by using X-ray diffraction (XRD), Brunauer-Emmet-Teller (BET) surface area, thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM). Temperature programmed gasification (TPG) was conducted to investigated the gasification reaction of rice straw and the product gases were analysed using online mass spectrometer. The gasification process was carried out in partial oxygen (5% O₂/Helium) environment heating from 50 to 900 °C with mass ratio biomass to catalyst of 2:1. From the results, Ni promoter was found to give the highest H₂ conversion followed by Co and Fe. The calcined limestone had shown to act as a catalyst and CO₂ sorbent thus enhancing the production of hydrogen. Moreover, additional of Na₂CO₃ during gasification process had shown a further increment of H₂ production.

Abstract: The sulfonated poly(ether ether ketone) (SPEEK)/bisphenol S diglycidyl ether (DEBS)/POSS ternary hybrids is designed and prepared to incorporate POSS into SPEEK to form a new cross-linked proton exchange membrane (PEM). Compared with the SPEEK, the ternary hybrids possesses lower water uptake (WU) and linear expansion (LE), but higher proton conductivity. The proton conductivity of SPEEK/DEBS/POSS can reach to 1.1×10^-1 S/cm.

Abstract: To develop hydrogen storage materials is the key to hydrogen storage. Magnesium theoretically stores 7.6 wt.% hydrogen, although it requires heating to above 300°C in order to release hydrogen. This limits its use for mobile application. However, due to its low price and abundance magnesium should still be considered as a potential candidate for hydrogen storage e.g. in stationary applications. Recent advances in Al-Mg alloy powders for hydrogen storage is presented in this paper. The main focus is on preparation of Mg-Al alloy and hydrogen storage properties of Mg-Al alloys. It is pointed the microstructure and components of Nano Mg-Al alloy have a great impact on the hydrogen-storage properties. Electrochemical deposition will be used to prepare the Nano Mg-Al alloy. Research will focuse on the nucleation mechanism and the influence of microstructure and components of the alloy on the hydrogen-storage properties.

Abstract: In Xinji Coal Mine under complicated geological conditions, regional faults. Experimental zone for near coal seam group mining(6-1,7-1,7-2,8 seam), The objective conditions with protective layer . The minefield of soft broken coal seam, Soft layered coal firmness coefficient f = 0.18. In the test area of 210601,210603 6-1seam protective layer mining face during the period, there were 8 abnormal gas dynamic phenomenon, To the coal mine safety production brought hidden trouble. On the basis of dynamic phenomenon occurring phenomenon, analysis of the dynamic phenomena, combined with the test area actual situation, summed up the6-1coal power causes, for guiding the 6-1safety mining and provide a theoretical basis, has important significance.

Abstract: Huolinhe(HLH) Lignite was used for this experiment. Among the several factors that influence lignite briquetting, particle size distribution was investigated in detail. Rosin- Rammler- Bennet equation (RRB) was used to describe particle size distribution. Uniformity index n and characteristic feature size De were also calculated. Compaction curves of the lignite shows that the whole compaction process can be divided into the particle re-arrangement stage, the plastic deformation stage and the whole deformation stage. More reasonable uniformity of particle size distribution and characteristic feature size would have higher compact density. The granularity of lignite had a distinct effect on the briquette strength. In order to increase the mechanical stability of briquettes small particle size lignite should be used.

Abstract: The explosion cavity, in which nine coal dust explosion tests are made, is made of circular pipe of 0.3m diameter and square pipes of 80mm section side. The analysis of test results shows the flame spread in coal Dust explosion is fast, big change and poor stability; Neither the maximum flame speed nor the spread distance keeps direct proportional to the amount of coal dust. However, there is the optimal coal dust consistency, with which the flame speed can reach its maximum. When the coal dust consistency is bigger than the optimal consistency, the flame speed curve will overall decline. Temporarily "hypoxia" is a very important factor that led to this situation.

Abstract: A non-turbocharged, direct-injection single-cylinder 1135 diesel engine was measured to investigate the engine fuel economy and emission characteristics with emulsified fuel that contains 18% water by volume. At the same time, the mechanism of reducing diesel engine NOX formation was discussed. The results showed that the diesel engine fueled with emulsified fuel leads to significant decrease in the emissions of soot and NO_x and proper increase in fuel-efficiency without modifications in engine structures comparing with the diesel fuel. This paper analyzed that the water physical chemical role has an effect on reducing emulsified fuel thermal NO and prompt NO formation.

Abstract: Anaerobic digestion is a widely applied technology to produce biogas from organic wastewater. The biogas calorific value depends on the methane-content. For biogas flows >100 m³/h, the two-step process is usually used for production of high calorific biogas from organic wastewater: the first step, anaerobic digestion; the second step, biogas purification. However, for biogas flows 3/h, biogas purification is not economical, and one-step process according to the big gap between methane and non-methane-gas in solubility at higher pressure or lower temperature, should be condidered. New anaerobic digestion processes, such as micro-aerobic process, electrolysis enhancing methane production process, process of internal circulation anaerobic digester (ICAD) with sewage source heat pump, may all enhance biogas producton or lower biogas production cost. In addition, suitable environmental conditions, such as organic loading rate (OLR), solid retention time (SRT), hydraulic retention time (HRT) and surface area, are all beneficial to enhance methane fermentation. Furthermore, new operation modes and optimal dose of trace metals might be selected.