Advanced Materials Research Vols. 236-238

Abstract: In this paper, biodiesel is successfully produced by the ester exchange reaction with solid base catalyst of K₂O/Ti-HMS based on soybean oil as raw materials. The result of which shows that K₂O/Ti-HMS has good ester exchange activity as solid base catalyst and the catalyst easily is separated from products. By single factor experiment, the influence of K₂O load, molar ratio of methanol and oil and catalyst dosage on the biodiesel conversion rate is researched and the optimal relationship between the above parameters is obtained.

Abstract: In order to explore high-efficiency utilization approach of lignite, Xianfeng lignite was extracted by toluene/methanol (3:1) mixed solvent under 300°C in an autoclave combined with high-temperature separator. Subsequently, the thermal extraction residue was oxidized by 3% hydrogen peroxide aqueous solution at room temperature. The raw coal and its residues of thermal extraction and oxidization were further extracted respectively by THF and CS₂/NMP mixed solvent, and the extracts and the extraction residues were characterized by FTIR. The results indicate that thermal extraction of lignite relaxes the network structure of coal matrix by disrupture the non-covalent bond interactions. The methylene bridge bond is easy to be oxidized into carboxyl and hydroxyl functional groups. Therefore, these results are very significant for the development of high-efficiency conversion technology.

Abstract: A combined theoretical and experimental program was carried out to study the effect of different solidification pressures on the heat transfer coefficient at the metal-mould interface during counter-gravity casting of A357 alloy. The interface heat transfer coefficient ( IHTC) at different temperatures and pressures could be calculated by substituting the dates of the experimental temperatures into the heat transfer coefficient equation, and the variable curves of the IHTC at the different temperatures had been obtained. The results showed that, the IHTC increased with raising the solidification pressure and it made a better contact between the metal and mould. IHTC is decreased with the temperature of interface of metal-mould falling. However, when the temperature of interface of metal-mould is less than a certain value, the IHTC is tend to a stable one.

Abstract: According to the poor performance about conductivity and cycle properties of conductive polyaniline (PANI) electrode material. The structure control techniques were used and the C/PANI compound electrod materials and fibrous PANI electrod materials were prepared.The electrochemical performance of PANI with different structure was examined .The examination results indicated: The structure control methods have obvious influnce on the electrochemical performance of PANI. The improvement of PANI structure may enhance the penetration of electrolyte and the intercalation of electrolyte ion. At the 2mA discharge current , the max capacitance of PANI-C and PANC-S is 435F/g and 387F/g, respectively .The capacitance retention rate of PANI-C and PANC-S after 500th cycle is 77% and 96%. The ion diffusion impedance of PANI-S material was lowest and show best capacitance and cycle performance.

Abstract: It is very important to the combustion processes of coal pyrolysis, so the catalytic effects of alkali, alkaline earth and transition metal on the brown coal (Yunnan,China) were investigated with a thermogravimetric analysis. These results show that the active pyrolysis orders are Mg>Ni,Fe>Na,K>Al₂O₃>CaO, and the maximal increment of conversion is 10.6% in brown coal.

Abstract: Scale deposition, including organic and inorganic substances, is always found in oil and gas field due to the changes of environmental factors in production. As a result, it is puzzled by the formation damage and wellbore plug. In fact, many wells face to complex scale, and even it is difficult to identify the type. In order to simplify treatment and promote efficiency, it is necessary to develop combining scale remover. A compound chemical scale remover is designed to relieve the complex scale comprised of calcium carbonate, guar gum and paraffin. Inorganic scale removing efficiency, paraffin removing rate and viscosity reduction ratio are used to determine the main agents respectively. Surfactants and lacquer solvent are added to develop an emulsion solution due to the incompatibility of water solution and organic solvent. This formula can dissolve 72.58% weight of calcium carbonate, reduce the viscosity of guar gum to 2.736mPa×s and remove the paraffin with a rate of 0.018 g/min.

Abstract: The hydrogenation of preasphaltene (PA), from Chinese Xiaolongtan lignite liquefied heavy product, was investigated with hydrogen storage materials in a batch autoclave. The effects of reaction conditions such as hydrogen storage materials and temperature on the yields of gas+oil, asphaltene, char and the conversions of preasphaltene were discussed. Preliminary studies indicate that increasing temperature not only improves hydrogen donor performance of hydrogen storage materials but also enhances conversion of feedstock PA and gas+oil yield. The conversion of PA and the yield gas+oil get to 72.02% and 41.46%, respectively, under 5% MgH₂, 5MPa initial hydrogen pressure, temperature 420°C and reaction time 30min. Meanwhile MgH₂ is stronger than NaBH₄ in hydrodeoxygenation of PA under the same conditions. Elemental and FTIR analyses were used to illustrate the structural characteristics of feedstock PA and remaining preasphaltene (RPA).

Abstract: The measurement for riser’s solids concentration is important but difficult. So, a high-efficiency and low-cost new predicted method based on the least square SVM method is proposed. The superficial operated gas velocity U_g and solids circulation rate ε_s are chosen as the effect factors of the solids concentration. Furthermore, the multiple linear regression model (Linear) and artificial neural net model (ANN) are also used to compare with the SVM model. By analyzing the training time and error, it is proved the SVM model has higher prediction accuracy and forecasting efficiency, which is a better choice for the riser’s solids concentration prediction.

Abstract: In this study, zeolite was prepared from fused fly ash with very little water treatment. The as-prepared zeolite was characterized by X-ray diffraction (XRD) and scanning electron microscope. XRD results showed that cancrinite was the major phase in the product. The influence of preparation conditions on the yield of zeolite was described. Experiments showed that the crystallization time of zeolite became shorter and the crystallinity of cancrinite became higher with the increase of NaOH dose in fusion stage. Based on the fact that the water was not enough to be as the solvent which was different from conventional method, it can be concluded that the synthesis mechanism of zeolite from fused fly ash is the Solid-state Conversion Theory.

Abstract: For investigation of wide use of drop tube furnace (DTF), the design and characterization of DTF and shaftless screw microfeeder are presented. With a developed group combustion model, a introduced non-dimensional number is to characterize the combustion zone of coal particles in DTF. Calculated relation is proposed to be operation criteria of DTF and design principle of feeder. It is found that the test results of coal feeder show good performance for micro feeding.