固定化脂肪酶催化制备生物柴油条件优化

本文探讨了以固定化脂肪酶为催化剂催化制备生物柴油中醇油比、水含量、游离脂肪酸酸值和催化剂使用寿命对菜子油酯交换反应的影响,并与以NaOH、固体碱纳米水滑石为催化剂生物柴油的制备条件相比较.研究表明:固定化脂肪酶为催化剂所需最佳醇油比最低,仅为4:1,游离脂肪酸含量对酯交换反应影响甚微,且有较强的抗水性,固定化脂肪酶催化剂可可重复使用6次;NaOH为催化剂酯交换反应抗水性最强,随游离脂肪酸的增加,酯交换转化率显著降低;纳米水滑石为催化剂可重复使用5次,酯交换产物易分离,所得产品完全符合德国生物柴油标准.     

脂肪酶催化合成生物柴油的研究

生物柴油是用动植物油脂或长链脂肪酸与甲醇等低碳醇合成的脂肪酸甲酯,是一种替代能源。这里探讨了生物法制备生物柴油的过程,采用脂肪酶酯化和酯交换两条工艺路线进行催化合成。深入研究制备过程中,不同脂肪酶、酶的用量和纯度、有机溶剂、低碳醇的抑制作用、吸水剂的作用、反应时间和进程、底物的特异性和底物摩尔比等参数对酯化过程的影响。试验结果表明,采用最佳酯化反应参数和分批加入甲醇并用硅胶作脱水剂的工艺过程,酯化率可以达到92％,经分离纯化后的产品GC分析的纯度可达98％以上,固定化酶的使用半衰期可达到360h。同时对酯交换制备生物柴油过程中,甲醇的用量和甲醇的加入方式对脂肪酶催化过程的影响作了初步研究,优化后的酯交换率可达到83％。     

荧光假单胞菌脂肪酶固定化及催化制备生物柴油的工艺研究

研究了不同因素对制备固定化荧光假单胞菌脂肪酶的影响及固定化酶的酶学性质,并初步探讨了利用该固定化酶制备生物柴油的工艺。以海藻酸钠明胶为复合载体,采用包埋法制备固定化荧光假单胞菌脂肪酶,考察了载酶量、颗粒直径等因子对固定化效果的影响,并用制备的固定化酶进行了酶促酯交换合成生物柴油的工艺研究,考察了反应条件如酶量、反应温度、甲醇流加方式、醇油比等因素对甲酯得率的影响。试验结果表明,制备固定化荧光假单胞菌脂肪酶的最优条件为:每克载体给酶量为300 IU,选用6号注射器针头(内径为0.5 mm);通过酯交换,催化大豆油合成生物柴油的最佳反应工艺参数为:固定化酶25%,醇油比4:1,含水量6%,反应温度40℃;此条件下反应35 h后,甲酯的最高得率可达82%。     

海滨锦葵油制备生物柴油工艺条件优化

以海滨锦葵油为原料制备生物柴油。通过单因素试验及正交试验研究了反应温度、催化剂用量、醇油摩尔比、反应时间、搅拌强度等因素对酯交换率的影响。结果表明,在试验范围内各影响因素对酯交换率作用的大小依次为：搅拌强度＞催化剂用量＞醇油摩尔比＞反应时间＞反应温度。海滨锦葵油制备生物柴油的最佳工艺参数为：搅拌强度为1800r.min-1,催化剂KOH用量为海滨锦葵油质量的1%,醇油摩尔比6/1,反应时间60min,反应温度65℃,在该工艺条件下,酯交换反应三次,酯交换率达到97.8%。     

最新专利文摘

CN101608131 一种无副产甘油的生物柴油制备方法 本发明公开了一种无副产甘油的生物柴油制备方法,将酯交换试剂与动植物油脂混合,在催化剂存在下,30～450℃反应2～18h,其中酯交换试剂与动植物油脂的质量比为1：1～30：1,催化剂添加量为动植物油脂质量的1％～30％,反应器内压力为0．05～30MPa;过滤除去催化剂并蒸馏除去过量的酯交换试剂,产品即为生物柴油;反应产物无副产物甘油。     

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CN101108975:耦合制备蓖麻油生物柴油的方法本发明公开了一种“浸出+反应”耦合法制备蓖麻油生物柴油的方法。以蓖麻籽为原料,在超声条件下或无物理场作用条件下,蓖麻油浸出与酯交换反应耦合制备生物柴油。浸出与酯交换反应一步完成,极大地简化工艺流程,节约生产成本;甲醇既为浸出溶剂又为酯交换剂,有利于循环和节约原料,也有利于后期物料的分离。解决了现有的生物柴油制备方法对油脂的质量要求较高,工艺路线较长,各种原料、试剂及设备消耗较大,试剂污染也比较严重,生产成本比较高的问题。CN101108976:一种生物柴油及其制备方法本发明涉及一种生物柴油及其制备方法。生物柴油在制备过程中,将原料油和预处理剂按一定比例在预处理装置中,加热搅拌反应后,过滤,进入预脂化装置中再添加酸性催化剂和粗甘油,加热、搅拌,循环后进入脂化装置中,加甲醇和碱性催化剂或酸性催化剂,加热,加速循环反应后,回收甲醇,放出甘油和分离出皂化物,得到的生物柴油水洗后蒸馏即可完成。所得的生物柴油产品满足现行德国、美国和我国新实行的《GB/T20802~2007》标准。不仅节约了能源,且甲醇、催化剂等消耗量少,能耗低,适用于各种原料油,经济性价比高,工艺简单...     

碱性离子液体1-甲基-3-丁基咪唑氢氧化物催化地沟油制备生物柴油的研究

本研究合成了碱性离子液体1-甲基-3-丁基咪唑氢氧化物,通过红外光谱和核磁共振检测与文献报道一致,以此离子液体为制备生物柴油的催化剂,发现具有很高的催化活性.在生物柴油的合成过程中,考察了离子液体的用量、醇与油物质的量比、反应温度和反应时间对酯交换反应的影响.结果显示,以地沟油制备生物柴油的最佳工艺条件为:醇油摩尔比8:1、反应温度70 ℃、反应时间110 min、催化剂用量为原料油质量的3.0 %.在此条件下, 脂肪酸甲酯转化率为95.7 %.由地沟油制备的生物柴油,其低温流动性能好,闪点高,除碘值较高外,其他主要性能符合0# 柴油标准,并且可以和0# 柴油进行调和使用.     

超临界甲醇酯交换法制备生物柴油研究进展

超临界甲醇法制备生物柴油是动、植物油脂与超临界甲醇发生酯交换反应生成脂肪酸甲酯的工艺。与传统的酸、碱催化法以及酶催化法等技术相比,超临界酯交换反应具有不需要催化剂、反应速度快、产物分离简单等突出特点。缺点在于反应温度和压力条件不够温和,对设备要求较高,操作费用可观。如何从系统工程的角度发挥其优点、克服缺点,则是未来该项技术能否实现工业化应用的关键。回顾了该技术的研究进展,重点对过程的影响因素进行了分析讨论。     

最新专利文摘

CN1775913:高酸值潲水油制备生物柴油的新工艺本发明涉及一种将废弃的植物油转化为生物柴油的新工艺。此工艺采用酯交换法,以浓硫酸、浓磷酸为催化剂、高酸值潲水油为原料,制备出的生物柴油已达国外现有的生物柴油的质量标准,并且与矿物柴油的性能指标接近。本工艺具有以下特点:(1)采用酯交换法制备生物柴油,以均匀设计的实验方法,优化出以浓硫酸、浓磷酸为催化剂、高酸值潲水油为原料,制备生物柴油的最佳条件,生物柴油的转化率高达98·5%。(2)针对制备柴油酸值高、颜色深、甲醇浪费等一系列问题,采用一种独特的后处理方法,使制备出的生物…     

乌桕油脂成分作为生物柴油原料的研究进展

生物柴油本质上是长链脂肪酸甲酯,工业上多通过酯交换反应进行生产.乌桕是广泛分布于中国的油料树种,其种子油脂含量高达40%左右,是生物柴油的优质原料.本文在介绍能源植物的种类及生物柴油生产概况的同时综述了乌桕皮油和梓油的提取工艺、用于催化乌桕油生产生物柴油的催化剂以及乌桕油及种子中脂肪酸组成等方面的研究进展.规范乌桕种质资源的标准化与分子标记辅助遗传育种、油脂代谢途径机理的揭示及转基因技术创制高含油新品种、新型纳米催化剂及新型高效固定化抗逆脂肪酶的研制对推动乌桕生物柴油的发展具有重要作用.     

Physicochemical characteristics and toxicity of nickel oxide particles calcined at different temperatures

The physicochemical characteristics and cytotoxicity of two types of commercial nickel oxide particles (black and green nickel oxide) and five types of nickel oxide particles prepared by calcination of the black nickel oxide at 600–1000°C were studied. Thermal analysis with mass spectroscopy showed that the black nickel oxide particles contained approximately 1.4% impurity, which seemed to be basic nickel carbonate. The calcination treatment at 600°C increased the nickel content and decreased the oxygen content, but these remained constant in the particles treated at higher temperatures (700–1000°C) and in the green nickel oxide particles. The water solubility of black nickel oxide particles was markedly greater than that of the other particles, especially in the first 24 h after mixing with water. The solubility of the calcined particles decreased with increasing calcination temperature. The cytotoxicity of these particles was evaluated by the viability of rat alveolar macrophages and by the inhibition of cell proliferation in Chinese hamster ovary cells. The black nickel oxide was the most cytotoxic of the particles examined, and this may be attributable, at least in part, to a rapid dissolution of nickel from the contained impurity. The toxicity of the calcined particles decreased with increasing calcination temperature. These results indicate that water solubility, which depends on calcination temperature, modulates the acute cytotoxicity of nickel oxide particles.     

The effect of cosolvents on the formulation of nanoparticles from low-molecular-weight poly(I)lactide

The aim of this study was to formulate nanoparticles from poly(I)lactide by a modified nanoprecipitation method. The main focus was to study the effect of cosolvent selection on the shape, size, formation efficiency, degree of crystallinity, x-ray diffraction (XRD) reflection pattern, and zeta potential value of the particles. Low-molecular-weight (2000 g/mol) poly(I)lactide was used as a polymer, and sodium cromoglycate was used as a drug. Acetone, ethanol, and methanol were selected as cosolvents. Optimal nanoparticles were achieved with ethanol as a cosolvent, and the formation efficiency of the particles was also higher with ethanol as compared with acetone or methanol. The particles formulated by ethanol and acetone appeared round and smooth, while with methanol they were slightly angular. When the volume of the inner phase was decreased during the nanoprecipitation process, the mean particle size was also decreased with all the solvents, but the particles were more prone to aggregate. The XRD reflection pattern and the degree of crystallinity were more dependent were more prone to aggregate. The XRD reflection pattern and the degree of crystallinity were more dependent on the amount of the solvents in the inner phase than on the properties of the individual cosolvents. The zeta potential values of all the particle batches were slightly negative, which partially explains the increased tendency toward particle aggregation.     

The effect of cosolvents on the formulation of nanoparticles from low-molecular-weight poly(l)lactide

The aim of this study was to formulate nanoparticles from poly(l)lactide by a modified nanoprecipitation method. The main focus was to study the effect of cosolvent selection on the shape, size, formation efficiency, degree of crystallinity, x-ray diffraction (XRD) reflection pattern, and zeta potential value of the particles. Low-molecular-weight (2000 g/mol) poly(l)lactide was used as a polymer, and sodium cromoglycate was used as a drug. Acetone, ethanol, and methanol were selected as cosolvents. Optimal nanoparticles were achieved with ethanol as a cosolvent, and the formation efficiency of the particles was also higher with ethanol as compared with acetone or methanol. The particles formulated by ethanol and acetone appeared round and smooth, while with methanol they were slightly angular. When the volume of the inner phase was decreased during the nanoprecipitation process, the mean particle size was also decreased with all the solvents, but the particles were more prone to aggregate. The XRD reflection pattern and the degree of crystallinity were more dependent on the amount of the solvents in the inner phase than on the properties of the individual cosolvents. The zeta potential values of all the particle batches were slightly negative, which partially explains the increased tendency toward particle aggregation.     

Phosphate supplying power of rock phosphates in an oxisol

Summary The P-supplying power of triple superphosphate, three apatitic rock phospates and a calcined aluminum rock phosphate were tested by measuring the quantities of fertilizer P recovered in soybean and in four chemical extractants, after 3-day and 75-day periods of contact between soil and fertilizer.The triple superphosphate supplied the highest amounts of P, but it lost efficiency during the longer incubation period. The rock phosphates maintained their original efficiencies, probably as a result of a balance between P released from the fertilizer and P converted into non-labile forms.The following coefficients of correlation between P uptake by soybean from an acid oxisol and P extracted by chemical extractants, after the two incubation periods, were found: 0.902^** for 0.01M CaCl₂; 0.823^** for anion-exchange resin; 0.720^** for 0.03N NH₄F+0.025N HCl; –0.037 (n.s.) for 0.025N H₂SO₄+0.050N HCl.The acid NH₄F solubilized residual calcined aluminum phosphate particles, and double acid extracted P from residual apatite particles, thus accounting for their poorer performances in predicting availability of fertilizer P.The relative efficiencies of the rock phosphates could largely be predicted after an incubation period of only three days. This finding attests to the presence in these rock phosphates of an easily soluble fraction of P which is not indicative of the degree of reactiveness of the phosphate as a whole.on leave at the Agricultural University during 1977.     

Luminescence study of monodispersed ZnS nanoparticles

Monodispersed ZnS nanoparticles have been successfully synthesized by a chemical precipitation method in an air atmosphere using polyvinylpyrrolidone (PVP) and sodium hexametaphosphate (SHMP) as surfactants. The synthesized nanoparticles were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectrometer (FT‐IR), UV–Vis optical absorption and photoluminescence (PL) spectra. Prepared surfactants capped ZnS nanoparticles are highly homogeneous and well dispersed. Optical absorption spectra showed a strong blue shift from the uncapped particles due to the quantum confinement effect. The capped ZnS emission intensity is enhanced than more the uncapped particles. The size of the synthesized particles is around 4–6.5 nm range. Copyright © 2012 John Wiley & Sons, Ltd.     

Preparation,characterization and luminescence properties of BiPO4:Eu nanophosphors

A facile chemical method was employed to prepare fine BiPO₄:Eu³⁺ phosphor particles calcined at the same temperature. Introducing lithium greatly affected the morphology of the samples and further affected the luminescence intensity. The samples were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy. The XRD patterns of BiPO₄:Eu³⁺ indicated a monoclinic phase. From the fluorescence spectra, the emission transition ⁵D₀ → ⁷F₁ is more prominent than the normal red emission transition ⁵D₀ → ⁷F₂. Based on the intensity ratios of ⁵D₀ → ⁷F₂ to ⁵D₀ → ⁷F₁ in the emission spectra, it can be concluded that introducing Li⁺ can improve the symmetry of the crystal lattice and modify the emission intensity. Sharp lines at 395 nm are the strongest of the f–f transitions and match well with near‐UV LED chips. Copyright © 2012 John Wiley & Sons, Ltd.     

Application of calcined waste fish (Labeo rohita) scale as low-cost heterogeneous catalyst for biodiesel synthesis

This paper explores the feasibility of converting waste Rohu fish (Labeo rohita) scale into a high-performance, reusable, low-cost heterogeneous catalyst for synthesis of biodiesel from soybean oil. The thermo-gravimetric analysis (TGA) and X-ray diffraction (XRD) analysis revealed that a significant portion of the main component of fish scale i.e. HAP (hydroxyapatite) could be transformed into β-tri-calcium phosphate when calcined above 900°C for 2 h. Scanning Electron Microscopy (SEM) morphology studies of the calcined scale depicted a fibrous layer of porous structure; while a BET surface area of 39 m(2)/g was measured. Response surface methodology (RSM) was employed to determine the optimal parametric conditions viz. methanol/oil molar ratio, 6.27:1, calcination temperature, 997.42°C and catalyst concentration, 1.01 wt.% of oil corresponding to a maximum FAME yield of 97.73%. Reusability results confirmed that the prepared catalyst could be reemployed up to six times, procreating a potentially applicable avenue in biodiesel synthesis.     

Effects of gasifying conditions and bed materials on fluidized bed steam gasification of wood biomass

The effect of steam gasification conditions on products properties was investigated in a bubbling fluidized bed reactor, using larch wood as the starting material. For bed material effect, calcined limestone and calcined waste concrete gave high content of H(2) and CO(2), while silica sand provided the high content of CO. At 650 degrees C, calcined limestone proved to be most effective for tar adsorption and showed high ability to adsorb CO(2) in bed. At 750 degrees C it could not capture CO(2) but still gave the highest cold gas efficiency (% LHV) of 79.61%. Steam gasification gave higher amount of gas product and higher H(2)/CO ratio than those obtained with N(2) pyrolysis. The combined use of calcined limestone and calcined waste concrete with equal proportion contributed relatively the same gas composition, gas yield and cold gas efficiency as those of calcined limestone, but showed less attrition, sintering, and agglomeration propensities similar to the use of calcined waste concrete alone.     

Mycocrystallization of gold ions by the fungus Cylindrocladium floridanum

The size and morphology determines the thermodynamic, physical and electronic properties of metal nanoparticles. The extracellular synthesis of gold nanoparticles by fungus, Cylindrocladium floridanum, which acts as a source of reducing and stabilizing agent has been described. The synthesized nanoparticles were characterized using techniques such as UV–Vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray analysis (EDAX), and high-resolution transmission electron microscopy (HR-TEM). Based on the evidence of HR-TEM, the synthesized particles were found to be spherical with an average size of 19.05 nm. Powder XRD pattern proved the formation of (111)-oriented face-centered cubic crystals of metallic gold. This microbial approach by fungus for the green synthesis of spherical gold nanoparticles has many advantages such as economic viability, scaling up and environment friendliness.     

表面活性剂对嗜盐嗜碱硫碱弧菌D301生成及利用硫颗粒的影响

【背景】微生物脱硫是脱除气体中硫化氢的一种有效方法,其中,硫颗粒的生成与代谢是控制生物脱硫效率的关键,但目前相应的控制方法很少。【目的】研究不同种类表面活性剂对硫碱弧菌D301生成及利用硫颗粒的影响。【方法】通过摇床培养,利用X射线衍射、冷场发射扫描电镜、能谱分析及傅里叶红外光谱对硫颗粒进行表征。【结果】单质硫主要以S₈形式存在,吐温-80和十二烷基磺酸钠(Sodium Dodecyl Sulfate,SDS)的添加对硫颗粒的形态及生成量影响明显。对照组中生成的硫颗粒呈规则球形,光滑完整,其表面附着蛋白质等生物大分子;加入0.01 g/L吐温-80后,硫颗粒呈长杆状、颗粒增大、利用速率减慢;加入0.3g/L的SDS后,硫颗粒呈短棒状、生成量减少、利用速率加快,同时延缓了硫碱弧菌D301的衰亡。【结论】添加表面活性剂可以改变硫颗粒形态并且影响其利用,是一种调控硫颗粒生成和代谢的有效手段。