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采用微波辅助稀酸法对棉花秸秆进行水解糖化。探索了微波辐射温度、微波辐射时间、料液比及硫酸浓度对秸秆水解糖化效果的影响。结果表明,微波辅助棉花秸秆稀酸水解糖化的最佳糖化工艺条件为:微波辐射温度80℃,微波辐射时间50min,料液比1∶16g/mL,硫酸浓度3.0%。各影响因素对还原糖收率的影响顺序为:料液比微波辐射温度硫酸浓度微波辐射时间。在最佳糖化工艺条件下,还原糖收率为3.17%。 相似文献
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金属离子助催化稀酸水解纤维素工艺的研究 总被引:1,自引:0,他引:1
以小麦秸秆为原料,采用正交试验考察了硫酸浓度、Fe2+浓度、反应温度和反应时间等因素对稀酸水解纤维素的还原糖得率的影响,得到了优化的纤维素水解反应工艺组合:反应温度180℃,Fe2+浓度0.0375mol/L,硫酸质量分数1%,反应时间90min。研究了Fe2+、Ni2+、Na+、Mg2+四种金属离子对稀酸水解纤维素制备还原糖的影响,结果表明,金属离子能明显提高稀酸水解纤维素的转化率和还原糖得率,其助催化作用的大小依次为:Fe2+Na+Ni2+Mg2+,Fe2+对稀酸水解小麦秸秆制备还原糖的催化效果最佳,还原糖得率最高可达73.05%,纤维素转化率达到85.79%。 相似文献
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选择催化效率高的固体酸SO42-/Fe2O3催化剂催化水解秸秆。用不同浓度的丙酸对秸秆进行预处理,考察了反应温度、反应时间、催化剂与秸秆的质量比以及有机酸的浓度等因素对秸秆水解反应的影响。结果表明:在丙酸浓度为100g/L、温度为120℃、m(催化剂)∶m(秸秆)为2.5∶1的条件下固体酸催化水解秸秆反应1h,得到的总糖含量最高为51.77%,比未经过预处理的总糖含量高6.41%。 相似文献
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稀酸水解菊芋制乙醇技术研究 总被引:1,自引:0,他引:1
考察了固液质量比、酸浓度、反应温度和反应时间4个条件对菊芋粉稀酸水解的总糖浓度和总糖转化率的影响。结果表明,菊芋稀酸水解的最优化条件为:固液比0.3,硫酸浓度3%,反应温度80℃,反应时间90 min。在此条件下水解菊芋,水解液中的总糖浓度为24.1%,总糖转化率为80.3%;水解液经过中和后,接入酵母菌发酵产乙醇,最终乙醇浓度可达到10.4%,乙醇得率为86.4%。 相似文献
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以玉米芯纤维素酶水解残渣为原料,利用对甲酚和硫酸对其木质素进行酚化改性。采用单因素和正交试验的方法探讨了硫酸浓度、反应温度、反应时间和硫酸用量对酚化改性产物的得率、酚―羟基含量的影响。利用FTIR、1H-NMR和GPC等手段对酚化木质素的结构进行表征。研究结果表明,酚化改性可以有效地提高木质素的酚羟基含量,降低木质素大分子的分子量。正交实验结果表明,反应温度对酚化改性的影响最大,其次是硫酸浓度,酚化改性的最佳工艺条件为:温度40℃,硫酸质量分数60%,时间60 min,硫酸用量20 mL/g(残渣),此条件下木素酚得率达53.85%,酚羟基含量为1.23 mol/C9,相对分子质量(w M)为3388。 相似文献
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Corn stover was separated into four derived streams: ethanol extractives (EE), hot water extractives (HWE), extracted cellulose, and extracted hemicelluloses. They were separately treated with 0.75% dilute sulfuric acid at 180°C for 40 minutes. Over 100 degradation products were separated and identified using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography (LC). These products contained compounds from several chemical classes, including sugars, aromatics, carboxylic acids, furans, alcohols, aldehydes, and cyclenes. Itaconic acid, succinic acid, fumaric acid, azelaic acid, DL-isoborneol, and 3-methyl-2-furoic acid were detected in the dilute sulfuric acid pretreated corn stover for the first time. Potential microbial fermentation inhibitors and valuable chemical building blocks were evaluated. In an effort to identify and develop inhibitors which are useful for controlling and improving the lignocellulosic biorefinery process, how they originated from the corn stover constituents was examined. 相似文献
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Kinetic studies of xylan hydrolysis of corn stover in a dilute acid cycle spray flow-through reactor
Hongman ZHANG Qiang JIN Rui XU Lishi YAN Zengxiang LIN 《Frontiers of Chemical Science and Engineering》2011,5(2):252
Xylan of corn stover was pretreated with 1%, 2% and 3% (w/w) sulfuric acid at relatively low temperatures (90°C, 95°C and 100°C) in a dilute acid cycle spray flow-through reactor (DCF). The hydrolysis of xylan to its monomeric xylose was modeled by a series of first-order reactions. Both biphasic and Saeman hydrolysis models were applied to fit the experimental data. The results confirmed that the kinetic data of xylan hydrolysis fitted a first-order irreversible reaction model and the experimental data. The reaction rates of xylose monomer formation and degradation were sensitive to catalyst concentration and temperature. Higher catalyst concentration and lower reaction temperature result in high xylose yield. The activation energy for xylose formation and degradation were determined to be 112.9 and 101.0 kJ·mol-1, respectively. Over 90% theoretical xylose obtained from corn stover can be used to produce ethanol, xylitol and fumaric acid by fermentation. 相似文献
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Xuebin Lu Yimin Zhang Ying Liang Jing Yang Shuting Zhang Eiji Suzuki 《Korean Journal of Chemical Engineering》2008,25(2):302-307
The object of this work was to study the xylose production by hydrolysis of corn stover with diluted sulfuric acid at 100
°C. Several concentrations of H2SO4 (2%, 4% and 6% w/w) and reaction time (0–300 min) were evaluated. Kinetic parameters of mathematical models for predicting
the concentrations of xylose, glucose and furfural in the hydrolysates were found. Optimal conditions for hydrolysis were
5.5% H2SO4 at 100 °C for 60 min; under these conditions, 86.7% of xylose yield and 2.82 g/g selectivity were attained, leading to liquors
containing up to 18.73 g/l xylose, 6.64 g/l glucose and 0.63 g/l furfural. The models could be successfully used to predict the concentrations of xylose, glucose and furfural within 0–300
min under experimental acid concentrations. Furthermore, the hydrolysis process of corn stover using dilute acid could be
conceived as the first stage of an integrated strategy for corn stover utilization. 相似文献
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盐酸水解玉米秸秆木聚糖的动力学研究 总被引:1,自引:0,他引:1
对稀盐酸水解秸秆半纤维素生成木糖水解液过程进行动力学研究。分别测定了不同温度下,不同水解时间水解液中木糖质量浓度以及其降解产物糠醛的质量浓度。利用Saeman模型拟合木糖生成过程。实验表明,该模型能够较好地描述木糖生成过程以及其降解产物糠醛的产生过程。通过曲线拟和确定了不同水解温度下木糖的生成速率以及分解速率常数,同时利用Arrhenius方程确定木糖生成活化能Ea为116 kJ/mol。综合比较不同温度下水解液中的木糖以及糠醛质量浓度,确定使用质量分数为2%的稀盐酸于120℃下水解60 min为最佳水解条件。其水解液中木糖质量浓度可达20.99 g/L,糠醛质量浓度可维持在1.46 g/L以下。 相似文献
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Although many previous studies have been carried on the enzymatic hydrolysis of corn stover after pretreatment with dilute sulfuric acid, this paper emphasizes the use of different conditions to attain the highest yields of two sugars, xylose and glucose, from both stages. The pretreatment was performed at a range of sulfuric acid concentrations of 2, 4 and 6 % at 80, 100 and 120 °C. Up to 77 % xylose yield was obtained while the glucose yield was only 8.4 %. The corresponding solid phase was hydrolyzed by cellulase and the influences of five factors and their interactions on enzyme hydrolysis were evaluated by response surface methodology based on one‐factor‐at‐a‐time experiments. The optimal levels for each variable to obtain the highest reducing sugar yield were as follows: enzyme concentration of 22 FPU/g substrate, substrate concentration of 77 g/L, temperature of 49 °C, pH 4.8 and reaction time of 38 h. A reducing sugar yield of 42.11 g/100 g substrate was achieved, which was consistent with the predicted value of 42.13 g/100 g substrate. Compared with the one‐factor‐at‐a‐time experiments, there was a 9.4 % increase in reducing sugar yield when the enzyme concentration was decreased to 3 FPU/g substrate, the substrate concentration increased to 17 g/L and the reaction time dropped to 22 h. The total sugar released from the two stages was 62.81 g/100 g substrate. 相似文献
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用微波可高效对生物质烘焙预处理,考察了不同微波烘焙过程对玉米秸秆主要组分的降解作用及酸、碱、甘油催化剂对纤维素转化效率的影响,并对预处理的玉米秸秆进行酶解实验。结果表明,单纯的微波预处理对玉米秸秆中主要组分纤维素、半纤维素和木质素均有强烈的转化作用。无催化剂微波烘焙后,样品中纤维素含量降低了30%。在微波烘焙中添加酸、碱、甘油催化剂,可选择性降解玉米秸秆中的半纤维素或木质素,有效提高预处理后玉米秸秆中的纤维素含量,添加NaOH后纤维素含量增加最明显,由33%增至42%,纤维素最高转化率达65%。 相似文献
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不同预处理方式对玉米叶和玉米秆酶解率的影响 总被引:1,自引:0,他引:1
1 INTRODUCTION Enzymatic hydrolysis of the cellulose to glucose from inexpensive and abundant sources, followed by ethanol fermentation to produce alternative liquid transportation fuels is very attractive[1―4]. However, lignocellulosic biomass must first be pretreated to open up its structure, so that the high yields vital to economic success can be realized. Pretreatment is currently one of the most expensive steps in such bio- conversion routes, which account for one-third of the total… 相似文献
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提出了同时糖化发酵预处理玉米秸秆生产燃料乙醇的动力学模型,利用最小二乘法确定了在发酵过程中,乙醇浓度、玉米秸秆固形物含量与发酵时间之间的关系。 相似文献