生物质燃料乙醇研究进展

本文分析了燃料乙醇发展经济、能源、环境、社会效益,肯定了其能源战略地位,提出几条实现我国生物燃料规模化生产的可行性建议以资借鉴。     

燃料乙醇的研究进展

由于能源、环境的潜在危机,燃料乙醇已经成为世界各国重点研究和推广的能源课题之一,在我国以乙醇代替能源也势在必行。对燃料乙醇的国内外研究现状以及生产工艺进行归纳总结,简要说明其发展前景。     

新能源燃料乙醇开发的必然性

随着国内经济的飞速发展,我国的能源产业正在面临巨大的挑战:能源供给不足,消费需求日益增长,对优质、安全、清洁的交通燃料需求的持续增长等,这使能源供给成为全球正面临的一个重大课题,然而这一课题对于迅速崛起的中国尤为重要。在未来25年内,中国的中产阶级人数将显著增长,进而将推动对更高性能的交通燃料的需求。即使考虑到未来汽车燃料使用效率的提高,到2030年中国交通燃料的总体预期需求仍将比2010年增加90%。目前中国超过一半的原油需求依赖进口。根据中国政府的规划,为了更多地依靠本土原材料来源满足这一预期的需求增长,除了石油产品之外,还需要将更多种类的交通燃料商业化。     

竹纤维制备的预处理方式比较及纤维素酶筛选

为了实现以生物方法制备竹纤维,本文以竹粉为研究对象,分析了几种纤维素酶吸附特性以及不同预处理方法对竹粉作用效果影响.实验表明,纤维素酶与竹粉的酶解作用发生在酶吸附竹纤维之后,纤维素酶的吸附在反应开始30min内较为明显,并逐渐达到饱和;通过对竹粉有机抽提、有机抽提后高温处理和有机抽提后超声波处理三种不同预处理方法发现,在相同酶处理工艺条件下,以紫外/可见分光光度计测定还原糖产量,发现采用有机溶剂加高温处理方式效果最好;研究了经不同时间的高温处理,以15m in处理时间最为合适.     

浅谈燃料乙醇工艺的化学工程创新

目前发酵工艺的放大仍停留在经验阶段,这与燃料乙醇发展的需求极不相称,采用化学工程的成熟理论及先进技术来研究燃料乙醇工艺过程具有重要的意义,本文重点阐述生化反应工程和生化分离工程中的化学工程分析。     

玉米秸秆不同预处理方法对小克银汉霉油脂合成影响的研究

对玉米秸秆进行了理化及生物预处理方法的研究,结果表明:采用生物处理结合纤维素酶处理后的玉米秸秆基质,在不添加碳源时,刺孢小克银汉霉的油脂合成有明显的提高。但是,单一的理化及生物预处理方法对刺孢小克银汉霉油脂合成无显著的影响。     

木质纤维原料制乙醇原料预处理技术

从预处理的必要性出发,论述了木质纤维原料的预处理技术,分析了主要预处理技术的特点和处理纤维质原料的效果,并对未来预处理技术的发展方向提出了建议,供从事木质纤维素制乙醇的研究人员参考。     

自动化仪表在燃料乙醇生产中的应用

随着全球环境污染严重,石油资源日渐枯竭,燃料乙醇己成为重要的替代能源之一,也是目前进入市场替代石化燃料的大宗可再生能源.     

燃料乙醇生产中先进工艺的应用

在我国推行乙醇清洁燃料,对我国的农业、能源、环保、交通等诸方面都将起到积极的推动作用。我国的酒精工业已有近一个世纪的发展历程,在全球经济一体化的大背景下,提高燃料乙醇的使用范围和利用率急需先进的工艺作为技术支撑。以发酵法生产的燃料乙醇,具有和矿物燃料相似的燃料性能,而其生产原料为生物源,是一种可再生能源。浓醪发酵是一种可以提高酒精产量,提高设备利用率,降低能耗的酒精发酵新方法。     

A facile route to prepare PdPt alloys for ethanol electro-oxidation in alkaline electrolyte

We adopted a displacement reaction in acidic solution that enabled the spontaneous reduction of Pd and Pt cations in conjunction with corrosive dissolution of Ni. The composition for the PdPt was adjusted by varying the concentration of Pd and Pt cations. From SEM images and XRD patterns, the PdPt formed an fcc alloy uniformly deposited on the Ni substrate. Electro-oxidation of ethanol was conducted in alkaline electrolyte for samples of Pd, Pt, and PdPt alloys. In cyclic voltammetric profiles, the Pd₇₇Pt₂₃ revealed the highest electrocatalytic ability in both apparent current and mass activity, followed by Pd₈₇Pt₁₃, Pd, and Pt. Similar behaviors were observed in life time measurements in which stable performances for ethanol electro-oxidation were obtained.     

直接乙醇燃料电池阳极电催化剂的研究进展

介绍了直接乙醇燃料电池(DEFC)具有无毒,来源丰富的优点,分析了DEFC在Pt上的电催化氧化机理,讨论了DEFC的阳极电催化剂的重要作用;探讨了具有高电催化活性的新型Pt基催化剂、新型非贵金属催化剂、新型催化剂载体、新型的催化剂制备方法等的研究现状;指明了阳极催化剂将是今后DEFC研究和发展的重要方向之一。     

复合纤维素酶预处理对漂白麦草纤维结构的影响

针对纤维素微纤丝(CMF)制备所需要高能耗的问题,以漂白麦草纤维为原料,利用SEM、FT-IR、XRD等研究复合纤维素酶预处理对漂白麦草纤维结构的影响;对酶处理后纤维的微观形貌、化学结构和结晶结构进行了分析与表征。结果表明,随着酶用量的增大,酶处理后的纤维表面变得疏松多孔,细胞壁表层脱落,直至纤维被切断,纤维素结晶度发生了先增加后降低,再增加再降低的周期性变化,纤维素平均聚合度逐渐减小;酶处理后纤维素没有引入新的官能团,纤维仍具有纤维素的基本化学结构,纤维素基本保持了天然植物纤维素的晶型。     

A comprehensive study on the effect of Ru addition to Pt electrodes for direct ethanol fuel cell

The electro-oxidation of ethanol was studied over nanosized Pt and different compositions of PtRu catalysts synthesized by the borohydride reduction method. Physicochemical characterizations of the catalyst material were made by X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with EDX analysis and transmission electron microscopy (TEM). XRD patterns showed that Ru induces a contraction of the Pt lattice. EDX provided the composition of binary catalysts while TEM images indicated uniform distribution of discrete nanoparticle of the catalysts with narrow range. The electro-catalytic activities of the materials towards ethanol oxidation were investigated through electrochemical techniques, viz. cyclic voltammetry (CV), potentiodynamic polarization, chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) at room temperature. The onset potential of ethanol electro-oxidation is lowered on bimetallic PtRu catalysts compared to that on Pt alone. Of the investigated catalyst compositions the one with the highest electrocatalytic activity was found to be Pt₈₂Ru₁₈. This enhancement towards ethanol oxidation is explained on the basis of a structural effect and modified bi-functional mechanism.     

Near-infrared analysis of ground barley for use as a feedstock for fuel ethanol production

The objective of this study was to explore the potential of near-infrared spectroscopy for determining the compositional quality properties of barley as a feedstock for fuel ethanol production and to compare the prediction accuracy between calibration models obtained using a Fourier transform near-infrared system (FT-NIR) and a dispersive near-infrared system. The total sample set contained 206 samples of three types of barley, hull-less, malt, and hulled varieties, which were grown at various locations in the eastern U.S. from 2002 to 2005 years. A new hull-less barley variety, Doyce, which was specially bred for potential use in ethanol production, was included in the sample set. One hundred and thirty-eight barley samples were used for calibration and sixty-eight were used for validation. Ground barley samples were scanned on both a FTNIR spectrometer (10 000 to 4000 cm(-1) at 4 cm(-1) resolution) and a dispersive NIR spectrometer (400 to 2498 nm at 10 nm resolution), respectively. Six grain components, moisture, starch, beta-glucan, protein, oil, and ash content, were analyzed as parameters of barley quality. Principal component analysis showed that barley samples could be classified by their types: hull-less, malt, and hulled. Partial least squares regression indicated that both FT-NIR and dispersive NIR spectroscopy have the potential to determine quality properties of barley with an acceptable accuracy, except for beta-glucan content. There was no predictive advantage in using a high-resolution FT-NIR instrument over a dispersive system for most components of barley.     

A simple way to prepare precursors for zirconium carbide

A precursor for zirconium carbide was obtained by just blending zirconium butoxide Zr(OC₄H₉)₄ (ZTB) and divinylbenzene (DVB). This precursor satisfied the requirements for use in ceramic matrix composites fabrication via precursor infiltration and pyrolysis (PIP) process, that is, it was a solution, cross-linked at 150 °C for 2 h, and transformed to ZrC matrix upon heat treatment at 1,600 °C with a ceramic yield around 40%. The cross-linking behavior, pyrolysis process, and optimal molar ratio (ZTB and DVB) of the precursor were investigated by IR, DSC–TGA, and XRD analysis. ZTB and DVB decomposed into ZrO₂ and carbon, respectively, at 400–500 °C, and ZrO₂ and carbon reacted with each other via carbo-thermal reaction at higher temperature to form ZrC.     

一种用于金刚石膜沉积装置的重入式微波谐振腔

微波等离子体化学气相沉积法(MPCVD)是制备高品质金刚石膜的重要方法,而MPCVD技术的关键是其设备核心部件谐振腔的设计。本文基于目前广泛应用的圆柱式和椭球式两种MPCVD谐振腔中微波传输的特点和其各自的优点,提出了一种重入式微波谐振腔的设计构想,并利用数值模拟的方法对这一构想进行了验证。模拟的结果表明,微波在重入式微波谐振腔内外壁之间的路径传输后,可在金刚石膜沉积台处形成一最强且相对均匀的电场。在相同的输入功率下,其形成的最大电场强度高于圆柱式和椭球式两种谐振腔时的情况。由于重入式的微波谐振腔具有结构简单、频率易于调节的优点,因而这一构想可为设计制造新型的MPCVD金刚石膜沉积设备提供参考依据。     

Characteristics of diethylenetriamine-crosslinked cotton stalk/wheat stalk and their biosorption capacities for phosphate

Two polymeric biosorbents were prepared from cotton stalk (CS) and wheat straw (WS) by the epichlorohydrin-diethylenetriamine-trimethylamine method. Amine-crosslinked cotton stalk (AC-CS) and wheat stalk (AC-WS) were used for the adsorption of phosphate, and their physicochemical properties as well as biosorption properties for phosphate were discussed intensively. Results indicated that the contents of holocellulose in CS and WS corresponded to the distinct phosphate adsorption capacities between AC-CS and AC-WS. Zeta potential and Raman spectra analysis illustrated the electrostatic attraction between phosphate ions and biosorbents. The adsorption of phosphate was not strongly pH dependent when the pH was about 4.0-9.0. The Langmuir isotherm provided the better fit and the maximum adsorption capacity (Q_max) was 51.54 mg/g for AC-CS and 60.61 mg/g for AC-WS. The saturated adsorption capacities of AC-CS and AC-WS in column were 49.05 and 41.9 mg/g, which accounted for about 80.3% and 81.4% of these biosorbents’ Q_max. NaCl and HCl solutions demonstrated the excellent regeneration capacities for the biosorbents, and after three times of adsorption-desorption cycles, the column adsorption capacities of these biosorbents were still higher than 92%.