Production of biodiesel from waste fryer grease using mixed methanol/ethanol system

Transesterification of waste fryer grease (WFG) containing 5–6 wt.% free fatty acid (FFA) was carried out with methanol, ethanol, and mixtures of methanol/ethanol maintaining the oil to alcohol molar ratio of 1:6, and initially with KOH as a catalyst. Mixtures of methanol and ethanol were used for transesterification in order to use the better solvent property of ethanol and rapid equilibrium using methanol. Formation of soap by reaction of FFA present in WFG with KOH instigated difficulty in the separation of glycerol from biodiesel ester. To untangle this problem, two-stage (acid and alkali catalyzed) method was used for biodiesel synthesis. More than 90% ester was obtained when two-stage method was used compared to ∼ 50% ester in single stage alkaline catalyst. In the case of mixed alcohol, a relatively smaller amount of ethyl esters was formed along with methyl esters. Acid value, viscosity, and cetane number of all the esters prepared from WFG were within the range of the ASTM standard. Esters obtained from WFG showed good performance as a lubricity additive.     

BKX-Ⅰ型并联机床的谐响应分析

应用有限元分析软件(ANSYS),对BKXⅠ型并联机床进行谐响应分析,分别得到了机床各节点沿机床的虚拟轴X、Y和Z向的位移谐响应曲线。在此基础上,还分析了该机床的谐响应规律,并明确了谐响应的特点,为改善此类机床的动态特性提供了一定的参考依据。     

LY-8602系列催化剂的失活原因及对策

通过催化剂的评价及表征，对LY-8602系列催化剂在低硫裂解汽油加氢时的失活原因进行了研究，结果表明，其活性下降主要是催化剂的活性中心相Co-Mo-s遭到破坏，使催化剂表面的具有加氢活性的Mo^4 峰减小所致。采用新研制的高活性加氢催化剂LY-9702与LY-8602构成复合床催化剂，可以使加氢产品合格。     

Parameter identification for nonlinear systems: Guaranteed confidence regions through LSCR

In this paper we consider the problem of constructing confidence regions for the parameters of nonlinear dynamical systems. The proposed method uses higher order statistics and extends the LSCR (leave-out sign-dominant correlation regions) algorithm for linear systems introduced in Campi and Weyer [2005, Guaranteed non-asymptotic confidence regions in system identification. Automatica 41(10), 1751-1764. Extended version available at 〈http://www.ing.unibs.it/∼campi〉]. The confidence regions contain the true parameter value with a guaranteed probability for any finite number of data points. Moreover, the confidence regions shrink around the true parameter value as the number of data points increases. The usefulness of the proposed approach is illustrated on some simple examples.     

虚拟环境平台上的Linux裁剪分析

分析在虚拟环境平台上（虚拟机上）,采用原有的和新的方法来裁减Linux系统,得到的效果和意义。     

TiCN基硬质合金刀具切削性能与切削机理研究

通过系统地切削试验，研究了TiCN基新型硬质合金刀具在耐磨性、抗冲击性、切削力、刀一屑摩擦系数、加工表面质量等方面的切削性能特点；并通过一定的理论分析，探讨了TiCN基硬质合金综合性能优越的切削机理。研究所得大量切削试验数据及回归经验公式等，可供TiCN基硬质合金刀具推广应用时参考。     

高分子量聚氯乙烯树脂增塑,填充体系的物理力学性能研究

本文研究聚合度及增塑剂、填充剂用量对高分子量聚氯乙烯（ＨＭＷＰＶＣ）树脂物理力学性能的影响规律，并将国内外ＨＭＷＰＶＣ树脂以及ＨＭＷＰＶＣ与通用型ＰＶＣ树脂进行了性能对比。结果表明，ＨＭＷＰＶＣ增塑、填充体系的拉什强度、撕裂强度冲击回弹性及压缩永久形变等物理力学性能均随聚合度的提高而有所增加，而且各项性能均优于通用型ＰＶＣ树脂，可有效地用作橡胶代用品。分子量相同的国内外ＨＭＷＰＶＣ树脂物理力学性能基本相同。但是，后者随着增塑剂用量的增加，弹性比前者有所提高；随着填充剂用量的增加，性能变化比前者缓慢．增加填充剂用量以降低制品的体积成本。笔者还时两者物理力学性能的差异与颗粒形态之间的关系进行了探讨。     

Hydrodenitrogenation and Hydrodesulphurization of Heavy Gas Oil Using NiMo/Al2O3 Catalyst Containing Phosphorus: Experimental and Kinetic Studies

In this work, a systematic study has been conducted to optimize the process conditions and to evaluate kinetic parameters for hydrodenitrogenation (HDN) and hydrodesulphurization (HDS) of heavy gas oil derived from Athabasca bitumen using NiMo/Al₂O₃ catalysts containing phosphorus (P). In the catalyst, the concentration of phosphorus was maintained at 2.7 wt%. Experiments were performed in a tickle‐bed reactor at the temperature, pressure and liquid hourly space velocity (LHSV) of 340‐420°C, 6.1‐10.2 MPa and 0.5‐2 h^?1, respectively. H₂ flow rate and catalyst weight were maintained constant at 50 mL/min and 4 g, respectively in all cases. Statistical analysis of all experimental data was carried out using ANOVA to optimize the process conditions for HDN and HDS reactions. Kinetic studies for HDN and HDS reactions were studied within the temperature range of 340‐400°C using the power law model as well as the Langmuir‐Hinshelhood model. The power law model showed that HDN and HDS of heavy gas oil follow first order kinetics. The activation energies for HDN and HDS reactions from the power law and Langmuir‐Hinshelwood models were 94 and 96 kJ/mol and 113 and 137 kJ/mol, respectively.     

Synthesis of Biodiesel from Canola Oil Using Heterogeneous Base Catalyst

A series of alkali metal (Li, Na, K) promoted alkali earth oxides (CaO, BaO, MgO), as well as K₂CO₃ supported on alumina (Al₂O₃), were prepared and used as catalysts for transesterification of canola oil with methanol. Four catalysts such as K₂CO₃/Al₂O₃ and alkali metal (Li, Na, K) promoted BaO were effective for transesterification with >85 wt% of methyl esters. ICP-MS analysis revealed that leaching of barium in ester phase was too high (~1,000 ppm) when BaO based catalysts were used. As barium is highly toxic, these catalysts were not used further for transesterification of canola oil. Optimization of reaction conditions such as molar ratio of alcohol to oil (6:1–12:1), reaction temperature (40–60 °C) and catalyst loading (1–3 wt%) was performed for most efficient and environmentally friendly K₂CO₃/Al₂O₃ catalyst to maximize ester yield using response surface methodology (RSM). The RSM suggested that a molar ratio of alcohol to oil 11.48:1, a reaction temperature of 60 °C, and catalyst loading 3.16 wt% were optimum for the production of ester from canola oil. The predicted value of ester yield was 96.3 wt% in 2 h, which was in agreement with the experimental results within 1.28%.     

Hydrogen Yield from Low Temperature Steam Reforming of Ethanol

Low temperature steam reforming of ethanol in the temperature range of 200–360°C was studied to maximize the production of H₂. The optimum reaction conditions in presence of a suitable catalyst can produce mainly the desired products H₂ and CO₂. Cu/Al₂O₃ catalysts with six different concentrations ranging from 0 to 10 wt.% Mn, were prepared, characterized and studied for the ethanol-steam reforming reaction. Maximum ethanol conversion of 60.7% and hydrogen yield of 3.74 (mol H₂ / mol ethanol converted) were observed at 360°C for catalyst with 2.5 wt.% Mn loading.