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Moso bamboo vinegar was treated with extractive and separation methods. The acidic, neutral, and phenolic fractions separated from ether-extracted vinegar were analyzed by gas chromatography and gas chromatography-mass spectrometry to identify the major components in moso bamboo vinegar. The compositions of eight moso vinegar fractions collected over different temperature ranges from 100°C to 480°C were also analyzed and their effects on regulation of germination and growth were studied by bioassay with seeds of watercress and chrysanthemum. The results showed that moso bamboo vinegar fractions with collection temperatures up to 250°C promoted radicle and hypocotyl growth and this effect became larger with increasing collection temperature for chrysanthemum. Moso bamboo vinegar collected from 250°C to 400°C had a strong inhibition on germination and radicle growth for both seed types when tested at 103 dilution. 相似文献
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竹醋液的精制方法探讨 总被引:4,自引:0,他引:4
采用减压蒸馏法、活性炭吸附法、澄清剂法对竹醋液原液进行精制,并采用气相色谱一质谱联用仪(GC-MS)对竹醋液原液和3种精制竹醋液组分进行分析比较。结果表明:采用减压蒸馏法精制竹醋液效果最好,话性炭吸附法效果次之,而澄清剂法效果较差;竹醋液是一种成分较复杂的混合物,其主要成分是水,其次是有机酸,醛类,醇类等物质;竹醋液的组分含量因精制方法不同而会引起成分的变化。 相似文献
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采用MCM-41分子筛作为催化剂,在线催化提质生物质真空热解蒸气,考察催化温度、催化床层高度和体系压力对有机相产物产率的影响,采用响应面法优化工艺参数;对油菜秸秆生物油有机相进行理化特性和成分分析,并对催化剂进行耐久性分析。结果表明:精制生物油有机相产率随催化温度和催化床层高度呈先增大后减小趋势,随体系压力增大而减小;当催化温度为502℃、催化床层高度为2.7 cm、体系压力为7 k Pa时,有机相产率为15.84%,精制生物油有机相热值达31.08 MJ/kg;经催化提质后,生物油有机相中脂肪烃类和醇类物质含量明显增加,同时芳香类和羰基类物质含量降低。在对MCM-41使用耐久性的研究中发现,当MCM-41使用约100 min后,生物油理化特性指数急剧下降,表明生物油品质变差;同时,催化剂失重率明显升高,表明催化剂上沉积的焦炭逐渐增多,催化活性降低,直至完全失活。 相似文献
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纤维素热裂解左旋葡聚糖生成过程模拟研究 总被引:2,自引:0,他引:2
为优化生物质热裂解产物中左旋葡聚糖(LG)产率,在改进的B-S机理模型的基础上,以纤维素热裂解为研究对象,对其热裂解过程中活性纤维素(AC)、LG以及乙醇醛(HAA)的演变和生成情况进行了模拟。结果发现纤维素热裂解过程中,由于一次反应吸热需求得不到满足,导致物料温度长时间内处于中温状态,恰好形成了生物质热裂解制取生物油保持中温的必要条件。作为纤维素热裂解最主要的产物,LG在物料内部并未发生强烈的二次裂解,HAA则几乎完全来源于AC的分解,物料内部LG和其他竞争产物浓度(质量浓度,下同)的区别主要取决于其竞争能力的大小,HAA浓度积累速度在反应后期的提高正是其竞争消耗AC优势的体现。挥发分二次反应主要发生在气相空间,随着气相停留时间和辐射源温度的增加,LG二次分解的程度提高。因此为获取高产率LG,中等辐射源温度和短气相停留时间是必要条件,仅以生物油产率为目的时,气相停留时间可适当放宽。 相似文献
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Catalytic pyrolysis of cellulose in sulfolane (tetramethylene sulfone) with sulfuric acid or polyphosphoric acid gave levoglucosenone,
furfural, and 5-hydroxymethyl furfural (5-HMF) up to 42.2%, 26.9%, and 8.8% (as mol% yield based on the glucose unit), respectively.
Pyrolysis behaviors of the intermediates indicated the conversion pathways, and the conversion: levoglucosenone → furfural
was found to require water. The control of the water content in the pyrolysis medium was quite effective in controlling the
product selectivity between levoglucosenone and furfural: mild vacuum conditions to remove the product water dramatically
enhanced the levoglucosenone yield, while steam distillation conditions increased the furfural and 5-HMF yields. 相似文献
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YAN Zhen ZHAO Yong* CHAI Yubo LIU Yurong WANG Shu . School of Material Science Technology Beijng Forestry University Beijing P.R.China .Research Institute of Wood Industry Chinese Academy of Forestry Beijing P.R.China 《中国林业科技(英文版)》2007,6(1):14-18
This paper studies the characteristics of larch bark pyrolysis and analyzes factors that affect the pyrolysis and the liquid pyrolytic component. The results are as follows: TG curve shows that the pyrolysis can be divided into three parts: drying process, pyrolytic process, and carbonate and calcinated process. Both the size of grain and the temperature rising rate affect the shape of TG and DTG. Vinegar and sedimentary tar are main components of pyrolyzate products. GC-MS is applied to analyze vinegar. It is shown that the vinegar is a highly complex compound which is composed of phenol and its derivatives (45.620%), organic acid (13.851%), keto derivatives (9.754%), aldehydic derivatives (8.573%), alcoholic derivatives (1.794%), ester and its derivatives (0.205%). 相似文献
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热解活化法制备微孔发达椰壳活性炭及其吸附性能研究 总被引:1,自引:0,他引:1
以椰壳为原料,采用热解活化法制备微孔发达活性炭。研究了活化温度、活化时间对活性炭孔结构和吸附性能的影响。实验结果表明:活化温度为900℃,活化时间为4 h,可制得比表面积为994.42 m2/g的微孔发达活性炭,其碘吸附值为1 295 mg/g,亚甲基蓝吸附值为135 mg/g。N2吸附结果表明活性炭的平均孔径在2 nm左右,总孔容积为0.503 9 cm3/g,其中微孔容积为0.430 3 cm3/g,微孔率达85.39%。对该活性炭进行CO2动态吸附实验,CO2饱和吸附容量为56.61 mg/g,在热解活化法制备椰壳过程中,随着活化温度的升高和活化时间的延长,活性炭的得率有不同程度的降低。 相似文献
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Summary The study was carried out in order to determine the effects of CCA on the pyrolysis and the combustion toxicity of wood. The results from CCA treated wood are summarized as follows: 1. CCA accelerated the beginning of pyrolysis of wood, increased the activation energies for the weight loss by pyrolysis, and increased the char yields in both air and helium. 2. Almost all the original amounts of cromium and copper were retained in the ash while some of the arsenic evolved into the gas phase, which increased with increasing temperature and air supply. 3. The combustion toxicity of wood samples was affected more by the sample density and CO concentration than CCA. It is concluded that for minimizing gaseous toxicants from arsenic, CCA treated wood must be burned at low temperatures with a reduced air supply. 相似文献
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新鲜生物质催化热解特性的研究 总被引:4,自引:1,他引:3
采用TG/DTG/DTA技术考察了新鲜小麦秸秆(WS)和玉米秸秆(CS)以K2CO3、Na2CO3、ZnCl2和CaO为催化剂时的热解特性,分析了新鲜生物质的热解特性,催化剂种类及用量对新鲜生物质热解特性的影响。结果表明,新鲜生物质的热解特性优于存放一定时间的生物质;加入催化剂后新鲜生物质的热解挥发分在不同温度区间重新分配,主要热解区间向低温推移,生物质的热解挥发分产率增加;其中CaO对于提高热解挥发分产率最有利;K2CO3和Na2CO3对生物质热解特性的影响规律一致;随着K2CO3用量增加,热解挥发分产率增加,起始热解温度向高温推移,主要热解区间温度降低,K2CO3用量为10%~15%时对生物质的热解最为有利。 相似文献
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木质生物质快速热解生物油产率影响因素分析 总被引:14,自引:1,他引:14
木质生物质能是可再生能源的重要组成部分,快速热解技术是国内外木质生物质能源化的热点研究课题.本文在简要总结木质生物质快速热解技术的基础上,着重对快速热解过程中热解温度、升温速率、压力、气相滞留时间、木质生物质物料特性、催化剂、热解反应器等因素对生物油产率的影响进行了论述,阐明了提高生物油产率的快速热解工艺条件. 相似文献
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Woodceramics (WCS) are new porous carbon materials that have been shown to possess many excellent properties, but the chemical
mechanism during pyrolysis has not been reported yet. In order to investigate this process, pyrolysis of medium density fiberboard
(MDF) was analyzed by thermogravimetry coupled with Fourier transform infrared spectroscopy (TG-FTIR) in this study. The results
showed that the pyrolysis consisted of three stages up to 700°C. The first stage of the pyrolysis occurred below 240.0°C and
was mainly due to moisture evaporation. The second stage between 240.0° and 390.2°C accompanied the main mass loss. The maximum
pyrolysis speed (mass loss) was about 3.79% per minute at 313.2°C. This was believed to coincide with the cleavage of ether
bridges between the wood material and phenol-formaldehyde (PF) resin, and pyrolysis of carbohydrate. At higher temperature,
the pyrolysis of PF resin and lignin was the main reason for the mass loss in the third stage. The microcosmic environments
of both the MDF and PF resin in the MDF treated with PF resin were different from the untreated MDF and PF resin, so that
the temperatures at which their pyrolysis occurred and the quantities of evolved gases were different. During the process
of WCS preparation, the rate of temperature increase should be very slow before it reaches 700°C, especially at around 313.2°C,
at which point violent pyrolysis occurs. Such temperature control should allow uniform sintering of the sample and should
reduce flaws in the product. 相似文献
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金属离子催化生物质热裂解规律及其对产物的影响 总被引:8,自引:0,他引:8
在红外辐射热裂解实验装置上研究了K^ 和Ca^2 催化纤维素热裂解规律及其对热裂解产物分布的影响。结果表明,中温条件下两种金属离子的催化作用主要都发生在固相中.仅有极少量进入液态或者气态产物空间,该特性为制取环保液体燃料提供了保证条件。从总体上讲,两种金属离子对热裂解过程的催化作用比较相似,在促进焦炭和气体产物生成的同时阻碍了生物油的产生。但是,经由催化脱水过程,生物油有机成分氧含量降低,品质得到了部分提高。分析其催化机理,K^ 有利于裂变和歧化反应,促进乙醇醛、乙醛以及低相对分子质量醇基、醛基、酮基化合物的生成;Ca^2 则强烈地影响单糖碎片的重整和异构化过程,促进呋喃类和杂环衍生物的生成。这一催化选择性为热裂解采用合适的条件和工艺,有目的地选取特定金属盐来优化产物的生成提供了基础。 相似文献
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我国竹醋液发展现状和展望 总被引:6,自引:0,他引:6
竹醋液是竹材热解或干馏的过程中得到的成分复杂的混合液体,因其优良的性能而具有广泛的应用前景。本文总结了自2001年以来我国学者对竹醋液的研究状况,综述了我国在竹醋液制备、组分、应用上的研究进展。并指出今后要加强对竹醋液制备综合因素的研究,保证竹醋液质量的稳定;同时还要加强作用机理和各种功效性及副作用的研究,解决技术瓶颈,扩大应用领域。 相似文献