响应面法优化棉籽油超声强化合成生物柴油工艺的研究

以棉籽油为原料,KOH为催化剂,通过超声波强化制备生物柴油(FAME)。采用四因素二次正交旋转组合设计实验。结果表明:采用超声波强化与机械搅拌反应体系相比,反应时间从40min缩短至20min,节能效果明显;得出了超声强化合成FAME的最佳工艺条件为:醇油比6.5:1,超声时间20min,占空比28%,催化剂用量0.9%,FAME的得率为97.35%,所得生物柴油各项指标基本达到欧洲EN14214和0#生物柴油标准。     

响应曲面法优化固体碱催化制备生物柴油的工艺

以固体碱硅酸钠为催化剂进行酯交换反应制备生物柴油,采用响应曲面法中的Box-Behnken模式对影响生物柴油转化率的4个主要因素(温度、催化剂用量、反应时间、醇油物质的量比)进行优化.建立生物柴油转化率的二次多项回归模型方程,并对回归方程系数进行显著性检验和方差分析.试验结果表明:当反应温度为66℃、催化剂用量为大豆油质量的2.1%、反应时间为7h、醇油物质的量比为8.6:1时,生物柴油的转化率最高,最高转化率预测值为75.78%,与实测值基本相符,优化模型有效可靠.     

微波辅助组合离子液体直接制备微藻生物柴油

采用小球藻、甲醇为原料,离子液体组合物作为提取催化剂,微波辅助原位一步法催化制备微藻生物柴油.考察微波功率、离子液体类型、离子液体用量、反应温度、反应时间、醇油物质的量之比等因素对酯交换率的影响,并与传统水浴加热机械搅拌法比较.结果表明:微波和离子液体对生物柴油的制备有协同促进作用,离子液体具有催化、提取与增溶的作用,...     

生物柴油精细化学品-蔗糖酯合成技术研究

以生物柴油和蔗糖为原料,在N2保护下采用无溶剂法合成蔗糖酯,以活性炭负载的碳酸钾为催化剂,确定了蔗糖酯合成技术的各项工艺条件:生物柴油与蔗糖的物质的量比为2∶1,在N2保护下,催化剂活性炭负载碳酸钾加入量为总物料量的6%,助溶剂硬脂酸钾加入量为15%,在135℃下反应3h,采用溶剂萃取法纯化粗产物,精制后的蔗糖酯产率以蔗糖记为86.4%。     

硫酸氢钠催化生物柴油合成反应的研究

以固体酸硫酸氢钠(NaHSO4·H20)为催化剂,以菜籽油和甲醇为反应物进行酯交换反应制备脂肪酸甲酯(生物柴油).采用正交实验考察了各因素对生物柴油产率的影响,得出最佳反应条件:反应温度为90℃,反应时间为12h,醇油物质的量比为40:1,催化剂用量为菜籽油质量的6%.极差顺序为温度、反应时间、醇油物质的量比、催化剂用量.     

米糠油超临界甲醇条件下制生物柴油

以毛米糠油为原料,采用超临界酯交换法制备生物柴油,旨在对毛米糠油进行充分利用.实验考察了醇油摩尔比、反应时间和温度对反应的影响,并用响应面试验设计优化出了最佳工艺条件:醇油摩尔比25.1,反应温度295.9℃,反应时间40.5min,最优工艺条件下的收率为79.89%.所得的生物柴油产品各项技术指标符合我国GB/T 20828-2007标准.     

固体酸催化剂在生物柴油合成实验中的研究

针对生物柴油催化合成技术中，采用一般催化剂所存在的问题，自制了4种固体酸催化剂，测试了它们在以大豆酸化油为原料制备生物柴油反应中的催化活性及重复使用性，确定了合成生物柴油的工艺条件。     

催化合成生物柴油的双金属络合物固体催化剂

制备了基于亚铁氰化锌的双金属氰化物络合物(DMC),可一步同时催化酯交换和酯化反应制备生物柴油,该催化剂体系具有不受水毒性影响的特点。用3wt%的DMC催化剂在433K,醇油摩尔比为16∶1以及水和脂肪酸含量各10wt%的条件下分别同时催化甘油三酯、脂肪酸和甲醇的酯交换、酯化反应,生物柴油产率可达98%以上。对催化剂进行X射线衍射、热重红外联用分析、元素分析、比表面积和孔体积测定、扫描电镜等手段表征,结果表明:该催化剂为晶态与非晶态组分混合结构,其表面晶态决定其在高水含量、高酸值的环境下仍具有较好的催化活性,验证得出活性位点可能为锌离子。     

包衣酶催化地沟油制备生物柴油

实验考察了以地沟油为原料,三阶段包衣酶催化制备生物柴油的工艺.以中心组合设计试验,选取反应时间、反应温度、包衣酶用量、醇油摩尔比和水分添加量为影响酯化率的主要因素,通过响应面分析得优化的工艺条件为:反应时间9.4×3h,反应温度54℃,包衣酶用量18.7%,醇油摩尔比3.6:1,水分添加量17.2%,在最佳条件下的酯化率为93.68%.     

固体碱催化猪油制备生物柴油

运用实验研究和理论分析相结合的方法,阐述猪油和甲醇在CaO催化剂作用下进行酯交换反应制取生物柴油的基本原理和操作方法,分光光度法测定甘油含量,计算生物柴油转化率,得出以CaO催化猪油制取生物柴油的适宜反应条件。结果表明:CaO做催化剂时,催化剂用量为2.0%,醇油物质的量比为6∶1,反应时间为150min,温度为60℃进行磁力搅拌,反应产率最高可达93.68%。     

Production of biodiesel from Jatropha oil catalyzed by nanosized solid basic catalyst

In this work, hydrotalcite-derived particles with Mg/Al molar ratio of 3/1 were synthesized by a coprecipitation method using urea as precipitating agent, subsequently with (MHT) microwave-hydrothermal treatment, and followed by calcination at 773 K for 6 h. These particles were micro-sized mixed Mg/Al oxides as characterized by SEM and AFM. But actually they were nanosized according to the calculations from XRD data. Because of their strong basicity, the nanoparticles were further used as catalyst for biodiesel production from Jatropha oil after pretreatment. Experiments were conducted with the solid basic catalyst in an ultrasonic reactor under different conditions. At the optimized condition, biodiesel yield of 95.2% was achieved, and the biodiesel properties were close to those of the German standard. The catalyst can be reused for 8 times.     

Optimization of long-term storage stability of Jatropha curcas biodiesel using antioxidants by means of response surface methodology

The present paper reports the results of the study of the effect of metal contaminants on the storage stability of Jatropha curcas biodiesel (JCB) with and without antioxidants. Taking 1,2,3 -Trihydroxybenzene/Pyrogallol (PY) as the most effective antioxidant based on the earlier work of the authors, JCB was mixed with different transition metals – Fe, Ni, Mn, Co and Cu in different concentrations. Induction period (IP) was measured using Rancimat method (EN 14112) as the stability parameter. Based on results, several correlations were developed for assessing the storage stability in terms of IP as a function of antioxidant, metal concentration and storage time. For the purpose of design of experiment, response surface methodology (RSM) has been used. From the experiments it is found that if metal concentration is 0 then, 200 g m⁻³ of PY is sufficient to make biodiesel stable for 6 months. If metal (Fe) concentration is 2 g m⁻³ or more, then 800 g m⁻³ PY is sufficient to make biodiesel stable for 5.5 months. The value of storage time for Ni, Mn, Co and Cu contaminated JCB is found as 3.62, 3.24, 2.76 and 2.07 months respectively if metal and antioxidants concentration is same in all the cases.The models developed by RSM shall be highly useful for predicting the optimum antioxidant concentration to achieve maximum storage stability of JCB as well as biodiesel from other resources under the conditions set for 3 factors (antioxidant concentration, metal concentration and time).     

Optimization of heterogeneous biodiesel production from waste cooking palm oil via response surface methodology

Heterogeneous transesterification of waste cooking palm oil (WCPO) to biodiesel over Sr/ZrO₂ catalyst and the optimization of the process have been investigated. Response surface methodology (RSM) was employed to study the relationships of methanol to oil molar ratio, catalyst loading, reaction time, and reaction temperature on methyl ester yield and free fatty acid conversion. The experiments were designed using central composite by applying 2⁴ full factorial designs with two centre points. Transesterification of WCPO produced 79.7% maximum methyl ester yield at the optimum methanol to oil molar ratio = 29:1, catalyst loading = 2.7 wt%, reaction time = 87 min and reaction temperature = 115.5 °C.     

A review on microwave-assisted production of biodiesel

Energy is the most important necessity for human existence on the earth. Limited crude petroleum resources and increasing awareness regarding the environmental impacts of fossil fuels are driving the search for new energy sources and alternative fuels. Biodiesel is a fuel which is renewable, biodegradable, environmentally friendly, and non-toxic in nature and has attracted considerable attention during the past decades. The costs of feedstock and the production process are two major hurdles to large-scale biodiesel production in particular. Various technologies have been developed to reduce the production cost. This paper attempts to extensively review microwave-assisted technology for biodiesel production. Additionally, different types of feedstocks for biodiesel production have been summarized in this paper. It is concluded that the microwave-assisted technique reduces the reaction time significantly in comparison with conventional methods. In addition, a high quality biodiesel can be obtained from microwave-assisted transesterification of different kinds of oils. Finally, the energy payback for 1kg biodiesel produced by microwave-assisted technology is calculated in this paper and it indicated that the system is sustainable. Therefore it can be a suitable method of decreasing the cost of biodiesel and can also help the commercialization of this fuel.     

Optimization of conversion of waste rapeseed oil with high FFA to biodiesel using response surface methodology

In the present study, waste rapeseed oil with high free fatty acids (FFA) was used as feedstock for producing biodiesel. In the pretreatment step, FFA was reduced by distillation refining method. Then, biodiesel was produced by alkaline-catalyzed transesterification process, which was designed according to the 2⁴ full-factorial central composite design. The response surface methodology (RSM) was used to optimize the conditions for the maximum conversion to biodiesel and understand the significance and interaction of the factors affecting the biodiesel production. The results showed that catalyst concentration and reaction time were the limiting conditions and little variation in their value would alter the conversion. At the same time, there was a significant mutual interaction between catalyst concentration and reaction time.The biodiesel produced in the present experiment was analyzed by gas chromatography/mass spectrometry (GC/MS), which showed that it mainly contained six fatty acid methyl esters. In addition, the diesel indexes analysis showed that most of the fuel properties were in reasonable agreement with the 0# diesel standard of China (GB252-2000) and the biodiesel standard of America (ASTM D6751).     

Optimization of biodiesel production from Annona squamosa seed oil using response surface methodology and its characterization

In the present study, Annona squamosa seed oil has been evaluated as a potential feedstock for biodiesel production. The response surface methodology was used to determine the optimal conditions for the biodiesel production using a central composite design. A quadratic polynomial was developed to predict the response as a function of independent variables and their interactions and only the significant factors affecting the yield were fitted to a second-order response surface reduced 2 factor interaction (2FI) model. Four process variables were assessed at five levels. A biodiesel yield of 98.19% was obtained at optimum conditions: 7.53:1 methanol to oil molar ratio, 1.18 wt% catalyst concentration, reaction temperature of 59.55°C, and reaction time of 47.29 min.     

氨基磺酸非均相催化菜籽油及废油脂制备生物柴油

采用正交试验和单因素试验的方法研究了氨基磺酸催化菜籽油及废油脂与甲醇的酯交换过程,考察了醇油物质的量比、催化剂用量、反应温度和反应时间对反应收率的影响。结果表明:菜籽油酯交换的最佳反应条件为醇油物质的量比6∶1,氨基磺酸用量为原料油质量的1.0%,反应温度60℃,反应时间20 min,此工艺条件下,脂肪酸甲酯的收率达到95.6%;废油脂酯交换的最佳反应条件为醇油物质的量比8∶1,氨基磺酸用量为原料油质量的1.0%、反应温度65℃,反应时间30 min,此工艺条件下,脂肪酸甲酯的收率达到87.5%。利用红外光谱表征了菜籽油和生物柴油的结构,气相色谱分析了生物柴油的组成。     

Optimization of hot pressing parameters in membrane electrode assembly fabrication by response surface method

The aim of this research was to study the effect of the membrane electrode assembly fabrication factors on the performance of a passive micro direct methanol fuel cell by studying the hot pressing parameters. The MEA was prepared with a Nafion 117 membrane and porous electrodes having an active area of 1 cm² with Pt and Pt/Ru catalysts of 8 mg cm⁻² loading at the cathode side and anode side, respectively. The Design of Experiment work was performed with the Response Surface Method using the Central Composite Design. The One-factor-at-a-time method was used to select the significant level of factors for the DOE method, which are temperature in the range of 100–135 °C and pressure in the range of 6.0–16.0 kgf cm⁻². The results show that the proposed mathematical model in the Response Surface Method can be used adequately for prediction and optimization within the factor levels investigated. The combined optimum hot pressing parameters that gave the highest performance of 7.23 mW cm⁻² predicted in this study are temperature 130 °C and pressure 6 kgf cm⁻².