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71.
George Jackson de Moraes Rocha Carlos MartinIsaias Barbosa Soares Ana Maria Souto MaiorHenrique Macedo Baudel Cesar Augusto Moraes de Abreu 《Biomass & bioenergy》2011,35(1):663-670
Integral utilisation of bagasse is a high priority for the diversification of the sugarcane industry. The application of a biorefinery philosophy to bagasse utilisation requires its fractionation into its main components: cellulose, hemicelluloses and lignin. The first stage in that process is the pretreatment, in which a considerable part of hemicelluloses is solubilised, and cellulose is activated towards enzymatic hydrolysis. In this work, a pretreatment method using a mixture of sulfuric and acetic acid is investigated. Two different solid-to-liquid ratios (1.5:10 and 1:10) were used in the pretreatment. Both conditions efficiently hydrolysed the hemicelluloses giving removals above 90%. The extractive components were also effectively solubilised, and lignin was only slightly affected. Cellulose degradation was below 15%, which corresponded to the low crystallinity fraction. The analysis of the morphology of pretreated bagasse confirmed the results obtained in the chemical characterization. 相似文献
72.
Young-Sam Oh Hyun-Seog Roh Ki-Won Jun Young-Soon Baek 《International Journal of Hydrogen Energy》2003,28(12):1387-1392
The steam treatment effect has been investigated over the doubly impregnated catalyst, Ni/Ce–ZrO2/θ-Al2O3, in steam methane reforming (SMR). The catalyst was remarkably deactivated by steam treatment but reversibly regenerated by H2-reduction. XRD results showed that the steam treatment resulted in the formation of NiAl2O4 which is inactive for SMR but it was reversibly converted to Ni by the reduction. The reversible oxidation-reduction of Ni state was also evidenced by XPS and it was observed that the formation of NiAl2O4 is more favorable at higher temperature. It is most likely that the alumina support is only partially covered with Ce–ZrO2 and most Ni directly interacts with θ-Al2O3 which would probably make easy formation of NiAl2O4 in the presence of steam alone. The results imply that, during the start-up procedure in SMR, too high concentration of steam could deactivate seriously Al2O3 supported Ni catalysts. 相似文献
73.
A chemimechanical (CM) pretreatment method was devised, wherein wood chips are acid-treated to weaken the physical structure then disc-refined to produce a fibrous substrate. CM pretreatment was directly compared with a common dilute acid (DA) pretreatment method, wherein wood is mechanically downsized to a powder or fiber substrate and then acid-treated. It was hypothesized that the CM pretreatment sequence would reduce the energy required for size reduction and increase enzymatic digestibility of the pretreated substrate. By treating wood chips in a dilute sulfuric acid liquor before the mechanical downsizing step, the net specific energy (NSE) of disc-refining was reduced by up to 95%. At the optimal acid treatment and disc-refining conditions determined within this work, CM pretreatment could produce a highly digestible lignocellulose substrate (95% cellulose conversion) while requiring less than 100 kWh/tonne od NSE for mechanical downsizing. A comparison of CM and DA pretreated hardwood revealed that CM pretreatment produced a significantly more digestible substrate than DA pretreatment. Differences in the digestibility of CM and DA pretreated substrates were attributed to differences in physical structure. CM pretreatment produced a substrate that consisted primarily of single fibers and small fiber bundles, while DA pretreatment produced larger fiber bundles. Furthermore, the CM pretreated substrate had a more accessible pore structure, and an altered distribution of surface lignin. 相似文献
74.
基于网格的动态性、虚拟性、分布性、资源共享性,传统的入侵检测系统已经很难有效解决现有的网格安全问题.结合带有超级结点P2P网格结构的特点,本文设计出一种面向网格的入侵检测系统.并提出了相应的告警信息预处理的算法思想. 相似文献
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纯棉纱卡冷堆前处理工艺 总被引:1,自引:0,他引:1
采用双氧水与烧碱分浴浸轧冷堆加常规氧漂工艺对纯棉纱卡进行前处理,解决了多年来纯棉纱卡平幅前处理中卷边、折皱等难题,提高了产品的质量,降低了能耗,开辟了纯棉纱卡冷堆练漂工艺新途径。 相似文献
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79.
这是一篇材料工程领域的论文。随着近年来新能源行业的蓬勃发展,2030年我国退役磷酸铁锂动力电池规模或达153.1万t。出于保护我国战略性矿产资源和减少环境污染的需要,研究开发出绿色、高效、可持续的废旧磷酸铁锂电池回收工艺已刻不容缓。本文以废旧磷酸铁锂电池的主要组成部分及一般回收流程为研究对象,介绍了预处理、正极材料、负极材料、电解液等多种回收工艺的原理、优缺点及研究现状。在此基础上,对废旧磷酸铁锂电池回收的未来研究方向提出了自己的观点,以期为我国废旧磷酸铁锂电池回收技术的产业化发展提供参考。 相似文献
80.
P.E. Domenic Grasso 《臭氧:科学与工程》1987,9(2):109-124
The formation of potentially carcinogenic organic halides has been shown to result from drinking water disinfection with chlorine. xidative treatment of organic halide precursors with ozone prior to chlorination has surfaced as an attractive technique for reducing the formation of these compounds. In addition to reduction of precursor levels, preozonation has been reported to effect other beneficial results in water treatment. This paper presents design methodologies to optimize the implementation of the ozonation process for water treatment applications. Pre-design considerations common to all ozonation design processes are discussed. Subsequently, design procedures for the ozone generation and contacting systems are reviewed. 相似文献