Advanced Materials Research Vols. 805-806

Abstract: With the conversion efficiency of tung oil methyl esterification as judgement index, univariate analysis for three main influencing factors, dosage of KOH and methanol, reaction time, were studied and optimized with response surface method to build a model in the one step methyl esterification of tung oil. Test and verify of this model were completed. The result showed that when dosage of KOH and methanol, time corresponded to 0.80g, 54.80g and 60min, the efficiency of tung oil methyl esterification was 94.52%. This result was only 4.72% lower than the predicted value from the model, which meant that the model was reliable to predict actual process. The efficiency of tung oil methyl esterification under two step process was 95.12%. There was little difference with one step process. But the total material cost of the optimized one step process was 1.76% less than that of the optimized two step process, and the reaction time was only need 1/4 that of two process. At the same time, operating process of one step was more simple and convenient. So, one step process for tung oil methyl esterification may be more cost-effective in industrial production.

Abstract: Clostridium acetobutylicum parent strain was treated by ultraviolet irradiation at different minutes. The UV treated strains were cultivated in cornmeal medium with butanol added to the medium prior to cultivation. By increasing butanol content gradually in the medium, high butanol tolerance mutants were screened. Results show that mutants by UV treated for 4 minutes display best butanol tolerance and high butanol productivity. With 12g/L butanol added in the medium, the mutants still grow rapidly and accumulated 18.0g/L butanol at the end of 69 hr cultivation. Using sweet corn stalk juice as raw material, the maximum butanol produced by fermentation with the mutants reached 15.3g/L and 18.3g/L in batch and fed-batch fermentation respectively.

Abstract: This research presents a study of the design and construction of a fertilizer rotary dryer in a pig farm which used waste heat at 400 degree Celsius from an electrical generator. The designed rotary dryer consisted of two pipes with lengths of 10 meters. These pipes consisted of a drying and a cooling pipe, each with a diameter of 0.5 meter. The power was supplied by two 5 horse power motors, and 2 horse power blowers were used to suck in hot and cool air for drying. The fertilizer, with an initial moisture content of 55-60 %db, was examined. Three parameters were varied to study the optimal condition of drying. These were rotary speed, degree of tilt angle and air flow rate. The rotary speed was varied at 10, 15 and 20 RPM, the degree of tilt angle was set at 1, 3 and 5 degrees, and the air flow rate was varied at 60, 120 and 180 cubic meters per hour. From the experiment, the result revealed that the condition of 1 degree of tilt angle, 10 rpm of rotary speed and an air flow rate of 180 cubic meters per hours were the optimal conditions for drying the fertilizer. The moisture in the fertilizer was reduced from 57.84 %db to 12.45 %db. The drying rate was 56.93 kg/h, and the thermal efficiency was 79.24 %. The energy consumption was 328.64 kWh/ ton. The capacity of the designed rotary dryer was 3 tons/day which is three times more than the amount of the traditional drying method. If the cost of the rotary dryer is 450,000 Baht, the payback period will be 3.73 months.

Abstract: Optimized synthesis conditions for biodiesel from microalgae oil and methanol using a modified immobilized lipase from Candida sp. as catalyst were investigated. The methanol tolerance of the immobilized lipase modified with succinic anhydride was determined. The results showed that the modified enzyme exhibited higher stability in methanol as compared with the unmodified enzyme. Then, the modified immobilized enzyme was applied to synthesize biodiesel using methanol and microalgae oil from Chlorella sp. Cells as substrates and the synthesis conditions were optimized. Tert-butanol was the most suitable organic solvent for biodiesel synthesis. The molar ratio of the reactants was found to be an important parameter affecting the yield of biodiesel. When the molar ratio of the methanol to Chlorella oil is 5:1, the yield of biodiesel catalyzed by modified lipase reaches the maximum of 92.5%. While the native immobilized Candida sp. lipase is used as catalyst, the yield of biodiesel get the maximum of 82.4% at the methanol / Chlorella oil molar ratio of 4. The reuse stabilities of the modified enzyme and unmodified enzyme were also studied in the present work. These experimental results proved that the immobilized lipase modified with succinic anhydride was suitable for the synthesis of microalgae-derived biodiesel.

Abstract: The molten alkali was investigated on the pyrolysis of fatty acid sodium salts; furthermore, the difference of pyrolysate between saturate and un-saturate fatty acid sodium salts was also given. In the presence of molten alkali, the pyrolysis of saturated sodium stearate leaded to high content of alkanes (nearly 60%) and low content of oxygen-containing compounds (almost 3%). But for the pyrolysis of un-saturated sodium oleate, high amount of aromatics (nearly 24%) and low amount of oxygen-containing compounds (1%) were detected. Compared with the pyrolysis without molten alkali, less oxygen-containing compounds were found in liquid pyrolysates. Therefore, molten alkali not only prompted deoxygenation of fatty acid sodium salts to hydrocarbons, but also had effect on the distribution of different compounds. In the process of pyrolysis, molten alkali partly changes into sodium carbonate. And the different raw materials also affected the distributions of pyrolysate.

Abstract: Analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was employed for the fast pyrolysis of glucose, cellubiose and cellulose in this study. The pyrolytic products from the three glucose-based materials were determined and compared to reveal the distribution differences. The results indicated that fast pyrolysis of the three materials obtained similar pyrolytic products, including the anhydrosugars, furans, linear carbonyls and cyclopentanones, but the distribution of the pyrolytic products differed from each other. The cellulose formed more anhydrosugars, but less carbonyls and furans than the glucose and cellubiose. The glycosidic bond of the cellubiose and cellulose would favor the pyrolytic depolymerization reactions to form various anhydrosugars, while inhibit the pyrolytic fragmentation reactions to produce linear carbonyls.

Abstract: The study determined the biogas production potential of different concentrations of biogas slurry co-digested with cornstalk at the TS of 8%. It turned out that pure biogas slurry mixed with cornstalk had the best performance. Besides, using biogas slurry without adding any water could keep the pH of the system at 6.9-7.2, while acidification happened when using other concentrations of biogas slurry and the pH went below 6.4.

Abstract: Numerical simulation had been used to study the combustion characteristic of vinegar residue in a straw-fired boiler in this paper. Achievement of the paper was based on a kind of CFD. The results paid more attention to the following points: the influences of different loads and the flow ratio of primary air and the second air on the combustion condition, the gas phase concentration, and mean mixture fraction. The results showed vinegar residue was easy to burn out. The increase of load was helpful to the combustion of vinegar residue in the straw-fired boiler. It was reasonable when the ratio of primary air and the second air is 1:1. And the straw-fired boiler showed good combustion adaptability to vinegar residue.

Abstract: Under different conditions,combustion characteristics of the single biomass,the single coal and the mixture of biomass and coal were analyzed by using thermogravimetric analyzer. Combustion characteristic parameters of the sawdust,the rice husk,the rice straw and the Baisha coal of Leiyang were studied,including ignition temperature,the maximum rate of combustion temperature,the burnout temperature and so on. The experimental results show that the biomass burning temperature is lower than the Baisha coal and there are two obvious weight loss phases in the combustion process of the biomass. However,there is only one in the coal. The ignition temperature and time of the coal can be reduced ,the temperature range of the entire combustion can be extended,the coal can be burnout more well and the fuel combustion characteristic can be optimized by blending combustion. With the increase of biomass mixing proportion, the ignition temperature of mixing samples was decreased more obviously. Moreover,when the biomass particle size becomes R200,compared with R90 particle size under the same blending ratio,its ignition temperature is more lower.

Abstract: In order to alleviate the shortage of raw materials in rural household biogas production and promote utilization of the formidable alien invasive species-alternanthera philoxeroides, mixed fermentation by alternanthera philoxeroides and corn stalk was designed and the performance was investigated in separated and different dry matter ratios (18.33, 6.25 and 3.46) treatments, by batch model at (35±1)°C.Results indicated that, the best biogas production appeared in the treatment of dry matter ratio of 6.25 when total solid (TS) loading of raw material was 8% and inoculating amount of biogas slurry was 20%, with TS and volatile solid (VS) biogas yields, and methane content of 325.74±5.11 mL/g, 456.06±4.87 mL/g and 60.56±1.23 %, respectively. Highly significant positive correlations (p˂0.01) were found between degradation rate of VS and four indexes such as average daily biogas yield, TS biogas yield, VS biogas yield and rate of change of total organic carbon (TOC) of fermentation liquid, while positive correlation between degradation rate of VS and methane content, and negative correlation between it and rate of change of volatile fatty acid (VFA), were not significant (p>0.05). Mixed fermentation by alternanthera philoxeroides and corn stalk could improve biogas production and achieve the gas peak in advance, therefore it had good feasibility.