Advanced Materials Research Vols. 512-515

Abstract: A constant temperature fermentation system was self-designed and used to study the relationships of gas production efficiency with time and temperature of digestion in anaerobic fermentation of Pineapple Leaf residue. Groups of experiments were conducted with total solids concentration (TS) being 20% and fermentation temperatures of four groups respectively being 25°C, 30°C, 35°C, and 40°C. Experiment results showed that the total gas yield of the group with 35°C was 662.8 L, which was much higher than gas yields of the other groups. The methane content of the group was 63.2%, almost the same with other groups. Multiple regression analysis was made with SAS software and the regression equation was set up. The optimum temperature, digestion time and maximum cumulative gas production of solids were 36.4°C, 55d, and 462.41mL/g respectively.

Abstract: This study examined the effects of an adenine-type cytokinin 6-benzylaminopurine (6-BA) on the growth and metabolism characteristics of Botryococcus braunii, one of the most promising oil-rich algae for biofuel production. The results showed that 6-BA of low dose (0.1-1.0 mg L^-1) would enhance the algal growth rate and biochemical synthesis, whereas too much (5.0 mg L-1) would be lethally toxic for B. braunii. Noticingly, though the maximum algal growth rate, chlorophyll and β-carotenoid content were observed in the treatment with 0.5 and/or 1.0 mg L^-1 6-BA, both the maximum algal hydrocarbon content and the highest hydrocarbon productivity were observed in the treatment with 0.1 mg L^-1 6-BA, which were respectively 2.45 and 3.48 times of the control (39.1% vs. 16.0%, 546 mg L^-1 vs. 157 mg L^-1). This finding has great implications for improving algae biofuels production by phytohormone.

Abstract: The pyrolytic characteristics and kinetics of Xanthoceras sorbifolia oil were investigated at heating rates of 10, 20 and 30 °C min^-1 in an inert atmosphere. The most probable mechanism function and activation energy pre-exponential factors were calculated by the Popescu, FWO and KAS methods. Three stages appeared during pyrolysis: moisture evaporation, primary devolatilization and residual decomposition. Significant differences in the average activation energy, thermal stability, final residuals and reaction rates of the X. sorbifolia oil at different heating rate were observed. Stage II of the X. sorbifolia oil could be described by the Mampel Power equation 22 (n=0.25). The average activation energy of X. sorbifolia oil was 346 kJ mol^-1.

Abstract: In this paper, plant straw densification technology has been studied. The corn straw was taken as raw material in the experiment. The influences of raw material moisture content, densification pressure and raw material size to the compact process have been studied. The results show that the 13%~18% moisture content of the corn straw is the best scope in compact process. When the raw materials are densified at a pressure of 60MPa, the products have smooth surface, high density. While the pressure continuously increases, the increase of density is not obvious. The raw material size 10~20mm are suitable for densification.

Abstract: As one of important technologies for briquettes production from straws, the normal-temperature wet briquetting technology of straws shows important practical significance in place of fossil fuels that are progressively reduced. According to the characteristics of the normal-temperature wet briquetting of straws having large displacement and large strain, this article provided a finite element calculation method for non-linear straw problems using the large-deformation elastic-plasticity principle. Based on description of straw status by Lagrange method, analyses were performed for deformation gradient tensor, displacement gradient tensor and rigid body movement, and then finite element equations were established for the normal-temperature wet briquetting of straws according to the Green strain, Drucker-Prager criterion and balance principle, providing references for numerical simulation for the normal-temperature wet briquetting of straws with computer software.

Abstract: Through the analysis on the relations of the three main participants of the government, the enterprise and the farmers, the thesis has established the gaming model between the enterprise and the forest farmers and found that only when the additional benefit they each obtain is larger than the construction cost for the development they paid, optimal combination of Nash equilibrium can be accepted by enterprises and forest farmers and Pareto improvement will be possibly formed， the smooth development of energy forest construction can be ensured.

Abstract: With the world’s focus on reducing our dependency on fossil fuel resources, one of the challenges will be the development of efficient catalysts for selective transformation of cellulosic biomass. Hydrolysis of cellulose to glucose is a key technology for effective use of lignocellulose because glucose can be efficiently converted into various chemicals, biofuels, foods, and medicines. Thus far, substantial efforts have been devoted to the degradation of cellulose but these processes have significant drawbacks. Some of these problems can potentially be overcome with the application of solid acid catalysts. In this paper, recent studies on heterogeneous acid-catalyzed hydrolysis of cellulose are summarized.

Abstract: The cold flow properties of rapeseed-based biodiesel (RME) were studied by gas chromatography-mass spectrometry (GC-MS), multifunctional low temperature tester and thermal analysis. Two approaches for reducing cold filter plugging point (CFPP) of RME were investigated: blending with winter petrodiesel, treating with cold flow improver (CFI) additives and the effect of CFI to combustion characteristics of RME. A good correlation model was proposed for prediction CFPP by RME blending ratio. The study shows that the RME was mainly composed of fatty acid methyl esters (FAME): C_14:0–C_24:0, C_16:1–C_22:1, C_18:2 and C_18:3. The mass fraction of saturated fatty acid methyl esters (SFAME) and unsaturated fatty acid methyl esters (UFAME) was 14.69% and 83.40%, respectively. The CFPP of RME was -7 °C. Blending with -10 petrodiesel (-10PD) decreased the CFPP to -12 °C. Treating with CFI additives (volume fraction ≤ 1.5%) decreased the CFPP of RME and RME/-10PD to -11 and -28 °C, respectively. Small amount of CFI additives hardly affected combustion characteristics of biodiesel. This study has effectively improved cold flow properties of biodiesel and provided guide for using biodiesel at low temperatures.

Abstract: In order to study the nature and function of Pyruvate decarboxylase (PDC, E.C.4.1.1.1), which is the key enzyme to produce ethanol by fermentation; full-length cDNA library was constructed with SMART technique from Monascus anka CICC 5031. The pdc gene, including a 1713-bp open reading frame, encoding a 570 amino acid protein, was obtained by screening the constructed M. anka cDNA library. The pdc gene was successfully heterologously expressed in E.coli BL21(DE3), accounting for 32.7% of total cellular proteins. Recombinant PDC was expressed in prokaryotic cells and purified by affinity chromatography, and native PDC was extracted and purified from M. anka through Sephadex G-25 and DEAE-anion exchange resin. The enzymatic characterization of both recombinant and native PDC were studied, respectively. The specific activity of recombinant and native PDC was 20.2 and 30.11U/mg respectively. Kinetic analysis indicated that recombinant and native PDC had the same optimum conditions: pH6.0, 30°C, the Km value for pyruvate of recombinant PDC was 2.6 mmol/L and native PDC was 0.56 mmol/L. The high activity and stable PDC from M. anka accounts for the new candidate resources of fuel ethanol production.

Abstract: In this article, the preparation and application of solid neutralizing agent was studied, liquid acid to purify crude biodiesel traditionally was substituted for the solid neutralizing agent and acquired satisfactory results. It was the biggest advantage to the process to apply solid neutralizing agent to purify crude biodiesel that became more simple than former and may not produce wastewater, the drawback of production biodiesel at present can be successful improved.