Reduction of high content of free fatty acid in sludge palm oil via acid catalyst for biodiesel production

In this study, sulphuric acid (H₂SO₄) was used in the pretreatment of sludge palm oil for biodiesel production by an esterification process, followed by the basic catalyzed transesterification process. The purpose of the pretreatment process was to reduce the free fatty acids (FFA) content from high content FFA (> 23%) of sludge palm oil (SPO) to a minimum level for biodiesel production (> 2%). An acid catalyzed esterification process was carried out to evaluate the low content of FFA in the treated SPO with the effects of other parameters such as molar ratio of methanol to SPO (6:1-14:1), temperature (40-80 °C), reaction time (30-120 min) and stirrer speed (200-800 rpm). The results showed that the FFA of SPO was reduced from 23.2% to less than 2% FFA using 0.75% wt/wt of sulphuric acid with the molar ratio of methanol to oil of 8:1 for 60 min reaction time at 60 °C. The results on the transesterification with esterified SPO showed that the yield (ester) of biodiesel was 83.72% with the process conditions of molar ratio of methanol to SPO 10:1, reaction temperature 60 °C, reaction time 60 min, stirrer speed 400 rpm and KOH 1% (wt/wt). The biodiesel produced from the SPO was favorable as compared to the EN 14214 and ASTM D 6751 standard.     

Influence of different reactor types on Nannochloropsis oculata microalgae culture for lipids and fatty acid production

Greenhouse gases emitted into the atmosphere by burning of fossil fuels cause global warming. One option is obtaining biodiesel. Nannochloropsis oculata was cultured under different light intensities and reactors at 25°C for 21 days with f/2 medium to assess their effects on cell density, lipid, and fatty acids (FAs). N. oculata improved cell density on fed-batch glass tubular reactor (7 L) at 200 μmol E m⁻² s⁻¹, yielding 3.5 × 10⁸ cells ml⁻¹, followed by fed-batch Erlenmeyer flask (1 L) at 650 μmol E m⁻² s⁻¹ with 1.7 × 10⁸ cells ml⁻¹. The highest total lipid contents (% g lipid × g dry biomass⁻¹) were 44.4 ± 0.8% for the reactor (1 L) at 650 μmol E m⁻² s⁻¹ and 35.2 ± 0.2% for the tubular reactor (7 L) at 200 μmol E m⁻² s⁻¹, until twice as high compared with the control culture (Erlenmeyer flask 1 L, 80 μmol E m⁻² s⁻¹) with 21.2 ± 1%. Comparing the total lipid content at 200 μmol E m⁻² s⁻¹, tubular reactor (7 L) and reactor 1 L achieved 35.2 ± 0.2% and 28.3 ± 1%, respectively, indicating the effect of shape reactor. The FAs were affected by high light intensity, decreasing SFAs to 2.5%, and increased monounsaturated fatty acids + polyunsaturated fatty acids to 2.5%. PUFAs (20:5n-3) and (20:4n-3) were affected by reactor shape, decreasing by half in the tubular reactor. In the best culture, fed-batch tubular reactor (7 L) at 200 μmol E m⁻² s⁻¹ contains major FAs (16:0; 38.06 ± 0.16%), (16:1n-7; 30.74 ± 0.58%), and (18:1n-9; 17.15 ± 0.91%).     

Study on the glycerolysis reaction of high free fatty acid oils for use as biodiesel feedstock

Biodiesel is the main alternative to fossil diesel and it may be produced from different feedstocks such as semi-refined vegetable oils, waste frying oils or animal fats. However, these feedstocks usually contain significant amounts of free fatty acids (FFA) that make them inadequate for the direct base catalyzed transesterification reaction (where the FFA content should be lower than 4%). The present work describes a possible method for the pre-treatment of oils with a high content of FFA (20 to 50%) by esterification with glycerol. In order to reduce the FFA content, the reaction between these FFA and an esterification agent is carried out before the transesterification reaction. The reaction kinetics was studied in terms of its main factors such as temperature, % of glycerin excess, % of catalyst used, stirring velocity and type of catalyst used. The results showed that glycerolysis is a promising pre-treatment to acidic oils or fats (> 20%) as they led to the production of an intermediary material with a low content of FFA that can be used directly in the transesterification reaction for the production of biodiesel.     

Partition coefficients for fatty acid esters in supercritical fluid CO2 with and without ethanol

The complex nature of fish oils was exploited to study the dependence of structural factors upon fatty acid ester solubility in supercritical fluid carbon dioxide (SCF-CO₂). Partition coefficients were determined for a number of components present in two mixtures of fatty cid ethyl esters derived from menhaden oil in SCF-CO₂ at 60°C and 125 bar. Analogous data also were obtained for SCF-CO₂ with 5% (w/w) ethanol added. The addition of ethanol was found to increase partition coefficients for all species, but resulted in a decrease of fluid selectivity. Aside from the chain length of a component, both the degree and position of unsaturation were found to be structural factors that affect the value of the partition coefficient.     

The effect of temperature on lipid classes and their fatty acid profiles inLipomyces starkeyi

The effect of environmental temperature on fatty acid contents of major lipid classes was determined inLipomyces starkeyi at 30, 20, and 10°C. When the temperature was reduced from 30 to 20°C, the linolenic acid content increased in phosphatidylcholine but fell with further reduction to 10°C. The relative contribution of phosphatidylcholine and phosphatidylethanolamine that contained the next lowest-melting fatty acids, palmitoleic and linoleic acids, increased on lowering the temperature from 20 to 10°C and, concomitantly, the combined phosphatidylinositol and phosphatidylserine fraction decreased, and triacylglycerols were accumulated.     

油酸异丁酯的合成及其对生物柴油降凝效果研究

油酸与异丁醇在离子液体催化剂的作用下发生酯化反应制备油酸异丁酯。研究了催化剂用量、醇酸配比、反应时间、反应温度等对酯化反应转化率的影响,并通过测定凝固点、冷滤点、粘度来考察脂肪酸异丁酯对生物柴油的降凝效果。结果表明,当催化剂用量为2%,醇酸体积比2∶1(摩尔比6.8∶1),反应温度100℃,反应时间3 h,转化率达到95.6%。降凝实验结果表明,把一定量的脂肪酸异丁酯添加到生物柴油中可有效地降低生物柴油的凝固点、冷滤点,改善其低温流动性能。     

溶胶-凝胶法制备Cu-ZnO-ZrO2催化剂：柠檬酸用量对催化剂性能的影响

采用溶胶-凝胶法以铜、锌、锆硝酸盐和柠檬酸为原料,改变柠檬酸用量,制备出一系列Cu-ZnO-ZrO₂催化剂。通过X射线衍射仪（XRD）、热重分析仪（TG-DTG-DTA）、H₂程序升温还原（H₂-TPR）、CO₂程序升温脱附（CO₂-TPD）、红外光谱仪（FTIR）及BET比表面积等表征手段对干凝胶及催化剂理化性能进行测试,并在催化反应活性评价装置上对催化剂的CO₂加氢合成甲醇反应活性进行评价,研究凝胶过程中Cu²⁺、Zn²⁺、Zr⁴⁺与柠檬酸结合方式对催化剂性能的影响。结果表明：改变柠檬酸用量可调控Cu²⁺、Zn²⁺、Zr⁴⁺与羧酸的配位方式,配位能力较强的Cu²⁺、Zn²⁺在凝胶制备过程中参与三维网络的构筑,而配位能力相对较弱的Zr⁴⁺游离于三维网络之外,从而差异化地调控催化剂中活性组分CuO、ZnO、ZrO₂晶粒尺寸大小。当柠檬酸的摩尔量为金属离子摩尔量的1.5倍时,催化剂中的活性成分CuO、ZnO、ZrO₂晶粒尺寸相互匹配,表现出较好的CO₂加氢合成甲醇催化性能。     

CO2碳酸化石灰岩酸解产物回收乙酸及副产沉淀碳酸钙

乙酸酸解石灰石造腔是一种建造地下储库同时环保地开采石灰岩制备沉淀碳酸钙的新方法。通过耦合乙酸酸解石灰石及酸解产物乙酸钙CO₂碳酸化的工艺过程,研究了乙酸酸解石灰岩的表面反应动力学和乙酸钙CO₂碳酸化的工艺技术条件。采用正交实验分析法,研究了CO₂碳酸化反应中乙酸钙浓度、反应温度、CO₂压力、反应时间对乙酸钙碳酸化反应制沉淀碳酸钙的影响,并通过正交实验确定了最优化操作条件。实验结果表明,乙酸酸解反应速率主要受乙酸浓度控制。CO₂碳酸化反应在当乙酸钙溶液浓度为0.631 mol·L^-1,CO₂压力为5.0 MPa,温度为80℃,反应时间为50 min时CO₂碳酸化效率达到最高（23.13%）,生成的沉淀碳酸钙产品各项指标均符合中国国标优级要求。     

Cu2O/PANI/不锈钢电极光电催化还原CO2

利用电化学氧化还原法在不锈钢基底上制备聚苯胺纳米管(PANI NTs),将Cu2O沉积到PANI NTs,得到Cu2O/PANI/不锈钢电极,通过循环伏安法（CV）研究Cu2O/PANI/不锈钢电极的电化学行为。采用X-射线衍射（XRD）、透射电子显微镜（TEM）对Cu2O/PANI NTs进行结构表征,借助乙酰丙酮分光光度法和气相色谱法对CO2还原产物进行检测。结果表明：PANI在不锈钢基底上以直立的中空纳米管的形式横向生长,内经约为100nm,外径约为200nm;Cu2O/PANI NTs具有优良的光电催化还原性能,对 /CO2具有催化活性;Cu2O/PANI/不锈钢电极光电催化还原CO215h 后溶液中甲醛的浓度为29.5μmol/L。     

Aspen Plus模拟高浓度H2S/CO2酸性气的选择性分离

以煤制氢尾气中的高浓度酸性气体H₂S和CO₂为对象,以聚乙二醇二甲醚（NHD）为吸收剂,使用PC-SAFT状态方程拟合了酸性气体CO₂和H₂S在聚乙二醇二甲醚（NHD）溶剂中溶解参数,运用Aspen Plus流程模拟软件,构建两级吸收分离工艺,实现H₂S和CO₂的高效分离,H₂S浓度由30%提升至98.7%,CO₂含量由55%提升至99.4%。由此,可以通过高效分离酸性气H₂S和CO₂,并以提浓后再资源化利用的方式实现酸性气的污染控制。     

变压吸附分离提纯CO_2技术的应用

本文叙述了变压吸附提纯ＣＯ２技术的基本原理和工艺过程，介绍了我国ＰＳＡ－ＣＯ２的开发过程及发展前景，对已开发的ＰＳＡ－ＣＯ２工业装置的生产成本和经济性进行了分析     

中国挤出聚苯乙烯（XPS）泡沫行业CO2混合发泡技术安全生产规范

简单介绍了二氧化碳（CO₂）混合发泡技术制备挤出聚苯乙烯泡沫塑料（XPS）的生产工艺,通过生产安全性分析,详细阐述了发泡剂储存区和高压泵房的安全隐患,分析了XPS泡沫生产过程中易燃发泡剂的可能释放部位和释放几率,并给出了发泡剂储存区、高压泵房和生产车间的安全保障措施,主要涉及到可燃气体探测系统、通排风系统、消防系统、防静电系统的安装要求。     

用于CO_2吸收的离子液体的合成、表征及吸收性能

以N-甲基咪唑和3-溴丙胺氢溴酸盐为起始原料,合成了一种含氨基的离子液体(ionic liquid,IL)——1-(1-氨基丙基)-3-甲基咪唑溴盐(简写为[NH2p-mim]Br),总产率为90.1%,溴含量为0.980 mol Br/mol IL,胺含量为0.948 mol NH2/mol IL。探讨了合成工艺,并通过1HNMR、13CNMR、IR和MS对产物结构进行了表征。吸收实验结果表明,该离子液体能够有效地吸收CO2,在40℃和106 kPa下,质量分数为45%的离子液体水溶液吸收CO2至饱和时,溶液中CO2的摩尔分数可达0.444 mol CO2/mol IL,接近理论吸收量0.5 mol CO2/mol IL;在90℃的真空状态下,吸收的CO2能够完全解吸,重复吸收实验表明,该离子液体吸收CO2的能力无明显下降。     

Novel amino acid ionic liquids prepared via one-step lactam hydrolysis for the highly efficient capture of CO2

This article proposes for the first time the preparation of a series of amino acid ionic liquids (AAILs) via one-step hydrolysis of cheap lactams for the capture of CO₂. The structures of the prepared AAILs are confirmed using NMR, FTIR, and ESI-MS, and their physical properties are also determined. It is found that these AAILs are reversible CO₂ absorbents with very high absorption capacities (0.15 to 0.18 g·g⁻¹ at 313.2 K and 1.0 bar), better than almost all task-specific ionic liquids reported in literatures. The absorption mechanism is also elucidated to be a combination of 1:1 and 2:1 stoichiometric reaction of AAILs with CO₂ from NMR, FTIR, reaction equilibrium thermodynamical modeling and quantum calculations. The AAILs have the advantages of simple synthesis, high yield, and using available cheap raw materials. It is believed that this kind of AAILs have great potentials to be used as efficient CO₂ absorbents.     

Influence of supercritical CO2 on the interactions between maleated polypropylene and alkyl‐ammonium organoclay

Supercritical carbon dioxide (scCO₂) has been proposed as an effective exfoliating agent for the preparation of polymer‐layered silicate nanocomposites, though there is limited fundamental understanding of this mechanism. This study looks at the interactions of this unique green solvent with three maleated polypropylenes of varying anhydride content and molecular size with an alkyl‐ammonium organoclay. Mixtures of compatibilizers and organoclay were melt‐annealed in a high pressure batch vessel at 200°C and subjected to either a blanket of nitrogen or scCO₂ at a pressure of 9.7 MPa. The structures and properties of these melt‐annealed mixtures were characterized by X‐ray diffraction, transmission electron microscopy, Fourier Transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, differential scanning calorimetry, and contact angle measurement. The results indicate that the plasticizing influence of scCO₂ aided intercalation and exfoliation for intercalants of moderate molecular size and anhydride content which would otherwise have limited diffusion into the clay galleries. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

CeO2的形貌对CuO/CeO2催化剂CO2加氢制甲醇性能的影响

采用水热法制备CeO₂纳米颗粒（W-CeO₂）、CeO₂纳米片（S-CeO₂）、CeO₂纳米棒（B-CeO₂）及CeO₂纳米八面体（O-CeO₂）,用浸渍法负载相同质量分数的铜形成CuO/CeO₂催化剂。通过扫描电镜（SEM）、高分辨透射电子显微镜（TEM）、X射线衍射（XRD）、拉曼光谱（Raman）、自动吸附分析仪（BET）、H₂程序升温还原（H₂-TPR）、N₂O滴定等表征技术对催化剂进行表征,并在可控温控压的固定床石英管反应器中对催化剂的催化性能进行评价。研究了不同形貌CuO/CeO₂催化剂对CO₂加氢制备甲醇的影响;结果表明,CuO/CeO₂催化剂的催化活性存在明显的形貌依赖性,催化剂的暴露晶面、比表面积、表面碱性位点、表面氧缺陷的差异均会对CO₂转化率、甲醇选择性和产率产生影响。其中,不同形貌CeO₂优先暴露晶面的活性顺序为S-CeO₂（{100}+{110}）>W-CeO₂{100}>B-CeO₂{111}≈O-CeO₂{111},暴露晶面活性越高,催化剂表面氧缺陷越多,CuO-CeO₂间相互作用越强,则催化活性越好。当为CuO/S-CeO₂时,催化剂表面中碱性位点最多,催化剂比表面积为88.8m²/g,铜分散度为19.2%,CO₂转化率为6.56%,甲醇选择性和收率为96.3%和0.063g/(g_cat·h),催化活性最好,由活性评价试验得转化率由高到低依次为S-CeO₂>B-CeO₂>W-CeO₂>O-CeO₂,可知CeO₂形貌差异会决定CuO/CeO₂催化剂的物化性能和催化活性,从而提升对不同形貌CuO/CeO₂催化剂催化CO₂加氢制甲醇的基础认识。     

Extra-framework charge and impurities effect,Grand Canonical Monte Carlo and volumetric measurements of CO2/CH4/N2 uptake on NaX molecular sieve

In this work, Monte Carlo simulation of CO₂, N₂, and CH₄ adsorption on zeolite 13X is carried out in grand canonical ensemble. FAU framework was used to reproduce the structure of zeolite 13X. Universal force field was used to calculate the interactions between adsorbates and 13X. Metropolis method was used for calculating adsorption isotherm. Volumetric measurements were carried out to confirm the simulation results. The simulation results using Universal force field showed good agreement with experimental results. Highest CO₂ uptake for this zeolite was found as 5.67 mol/kg from GCMC. Isosteric heat of adsorption was investigated to find the heat released during adsorption of each gas. The simulation result of isosteric heat of adsorption for CO₂, N₂, and CH₄ was utmost 17.00, 4.37, and 6.14 kcal/mole, respectively. Radial distribution graphs were used to find affinity of constituents of zeolite for CO₂. Henry’s constant evaluation was also performed at low pressure to find the selectivity of the structure. Henry’s constant of CO₂ in an equimolar mixture of N₂ and CH₄ was calculated 3.49 and 1.49 mol/kg.kPa, respectively. Finally, simulation results were fitted to Toth and dual-site Langmuir isotherms to find the best fit that belongs to dual-site Langmuir.     

燃煤净烟气中共存杂质对膜法捕集CO2影响现状

膜法捕集CO₂是现役燃煤电厂碳减排的重要手段之一，在实际应用中膜法捕集系统通常适合安装在湿法脱硫系统下游，鉴于脱硫净烟气中的颗粒物及气态污染物难以完全脱除，同时水汽接近饱和状态，气相中的共存杂质以及吸收液组分与膜及膜材料相互作用，会对膜法捕集CO₂性能造成严重影响。本文综述了烟气中共存气态、颗粒物组分及液相吸收剂对膜分离、膜吸收宏观性能、膜微结构及材质的影响，以及燃煤脱硫净烟气环境下膜法捕集CO₂长期运行性能及变化规律的研究现状，指出了抑制膜失效的技术方法，以期为突破膜法捕集CO₂技术发展的瓶颈，实现膜的稳定高效运行提供参考。     

饱水竹木漆器的超临界CO2脱水干燥研究

用超临界CO2对战国时代的饱水竹木漆器(含水率大于200%)进行脱水干燥。结果表明,超临界CO2脱水干燥的最优工艺条件为:干燥温度50℃,压力25 MPa,CO2流量为20 kg/h,脱水干燥5h。在该条件下,脱水干燥的竹木漆器,其含水率下降到了15%以下,漆皮完好如初,色泽鲜亮,样品形状完好、无收缩开裂损坏等现象,符合文物脱水保存的要求。     

Si掺杂对Cu/ZrO2催化CO2加氢制甲醇性能的影响

为了提高Cu/ZrO₂催化剂在二氧化碳加氢制甲醇中的催化活性,制备了一系列不同Si/Zr的Si-ZrO₂载体并负载5%（质量分数）Cu得到了Cu/Si-ZrO₂催化剂。对所制备的催化剂进行了X射线衍射（XRD）、N₂物理吸脱附（BET）、X射线光电子能谱（XPS）、氢气程序升温还原（H₂-TPR）、二氧化碳程序升温脱附（CO₂-TPD）及高分辨透射电子显微镜 （HRTEM） 的表征。结果表明,Si的掺杂使得Cu/ZrO₂体系获得了稳定的晶相,大的比表面积和更多的碱性位点,尤其是中强碱性位点,同时产生了更多的氧空位,促进了CO₂的吸附和转化,因此得到了更高活性的催化剂。当Si与Zr的摩尔比为0.2时,在质量空速为6000 ml·g^-1·h^-1,温度为220℃、压力为3.0 MPa,V（H₂）∶V（CO₂）=3∶1（体积比）条件下,催化剂的CO₂转化率为4.6%,CH₃OH选择性为85%。