共查询到17条相似文献,搜索用时 93 毫秒
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通过正交试验考察了蔗渣在水与四氢萘混合溶剂中液化过程的5个因素对蔗渣转化率的影响.蔗渣在混合溶剂中的优化工艺为:反应温度270 ℃、反应时间30 min、固液比(蔗渣与溶剂质量比)1:6、碱浸预处理NaOH用量4%、四氢萘用量(占总溶剂质量分数)50%.各因素的影响次序:NaOH用量>反应温度>四氢萘用量>固液比>反应时间.在此工艺条件下,蔗渣转化率可达到97.9%.实验结果表明,四氢萘部分取代液化溶剂中的水,可以有效提高蔗渣液化效率,同时降低反应温度及压力,促进实验操作条件的改善. 相似文献
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植物纤维在供氢溶剂中的液化反应 总被引:6,自引:1,他引:6
用热化学液化方法可以将植物纤维原料液化成为烃、醇、酚、羧酸等多种有机物,这些有机物可做液体燃料和化工原料。使用供氢溶剂,可以起到类似于加氢反应的作用,即封闭液化生成的碎片自由基,防止碎片的重结合形成更难以分解的缩合产物。文章主要综述植物纤维的主要成分纤维素和木质素在供氢溶剂中的液化工艺以及反应的机理,以及催化剂在植物纤维液化中的作用和催化机理。 相似文献
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将离子液体氯化1-丁基-3-甲基咪唑([BMIM]C1)、水、固体酸催化剂组成的混合溶剂应用于微晶纤维素的预处理过程中,并尝试把经过预处理的微晶纤维素应用于随后的溶剂液化的研究中,对经过混合溶剂处理后的微晶纤维素进行表征分析。通过测定纤维素的聚合度、官能团基变化、热重分析、结晶结构和表面结构等对微晶纤维素结构进行比较分析。通过对苯酚溶剂液化的基本表征、残渣物的结晶结构以及生成物相对分子质量的变化了解了混合溶剂对微晶纤维素的处理效果。结果表明,通过混合离子液体[BMIM]C1和水并且添加固体酸催化剂形成新的混合溶剂体系对微晶纤维素进行预处理,发现溶剂在保留纤维素主要葡萄糖单元的同时能够有效地降低聚合度。聚合度从未处理时的190降到样品[B]C1(10)的165和样品[B]C1(10)+NR50的151。混合溶剂对非结晶或低结晶物质具有一定的溶解能力,并且对高结晶性纤维素部分的氢键结构起到破坏作用和造成整体结晶结构的歪曲。在随后的液化过程中,处理后的纤维素液化效率有所提高,在反应2min时,固体酸加混合溶剂处理的微晶纤维素液化残渣率为19%,而未处理的液化残渣率29%。表明使用了混合溶剂添加固体酸的溶剂体系对加速液化的效果更佳,预处理对最终液化生成物的性质影响不大。 相似文献
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为考察煤焦油作为煤油共处理溶剂的反应效果,以高温煤焦油为对象,利用1H核磁共振光谱、红外光谱等分析方法表征高温煤焦油加氢前后结构变化,计算高温煤焦油加氢前后的平均分子式和平均结构参数。通过高温煤焦油加氢前后与煤的共处理试验,研究高温煤焦油加氢后结构变化对供氢性能的影响。结果表明,高温煤焦油加氢前后平均结构变化明显,加氢使部分芳环被取代,侧链发生断裂,芳烃加氢饱和形成氢化芳烃或发生开环反应形成其他脂肪结构,芳香氢HA含量由0.743下降到0.605,Hα、Hβ和Hγ分别提高0.109、0.022和0.705,加氢后高温煤焦油PDQI指数提高0.68,供氢效果明显改善,原料转化率、油收率分别提高1.24%和3.92%,沥青烯、前沥青烯产率下降2.25%,产物组成一环至四环化合物分别增加0.79%、0.53%、2.97%和0.83%,H/C原子比由0.99提高至1.03。说明加氢后焦油用于煤油共处理反应,促进了共处理反应重质产物向轻质产物的转移。 相似文献
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在间歇式高压反应釜中,在镍基催化剂NiMoS/Al2O3催化下研究了反应温度(180~340℃)对乙醇水蒸气重整制氢的影响,并以乙醇/水为混合溶剂,玉米秸秆为原料研究了其在混合溶剂下的直接液化行为。结果表明:在添加NiMoS/Al2O3催化剂的条件下,当反应温度提高到320℃时,乙醇水蒸气重整反应发生,伴随着CO、CO2、CH4、H2和CnHm的产生,其中H2产量最高为47 mmol,进一步提高温度至340℃,H2产量增加到122 mmol。反应温度为340℃条件下,玉米秸秆液化油的收率由未添加催化剂时的21.26%增加到添加催化剂后的29.57%,热值由32.14 MJ/kg提高到33.89 MJ/kg。GC-MS分析得出生物油的主要成分为酚类、酯类和酮类,且添加催化剂后酚类的量下降了23%,有助于提高生物油稳定性。 相似文献
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Isao Mochida Kenjiro Iwamoto Tsutomu Tahara Yozo Korai Hiroshi Fujitsu Kenjiro Takeshita 《Fuel》1982,61(7):603-609
Reactivities of several coals of different ranks have been examined in degrading extractions with aromatic solvents under apparently non-hydrogenative reaction conditions. Pyrene and A240 pitch liquefied the fusible coals in high yields and the slightly-fusible coals in moderate yields, indicating the importance of fusibility in such liquefaction processes. A240-LS pitch is a powerful solvent for slightly-fusible coals. Considerable amounts of pyridine- or THF-soluble fractions were produced especially with A240-LS pitch. A240 pitch is a better solvent than pyrene for some slightly-fusible coals. However, the extent of depolymerization of liquefied coal, pyridine- or THF-solubility, was definitely inferior. Yields of such fractions are higher for lower-rank coals. The mechanism of coal liquefaction under apparently non-hydrogenative conditions is discussed with emphasis on the stabilization of thermal fragments derived from the coal. 相似文献
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The UDES-S liquefaction process treats concentrated pastes (20% of initially present solids) of finely divided (dp < 0.5 mm) lignocellulosics in organo-solvolytic media by means of thermo-mechanical action in homogenizing valves. The work described in this paper was carried out with Populus Deltoides in a process development unit capable of processing up to 4 kg of dry wood per hour. The model solvents used were creosote oil and ethylene glycol, which represent solvents that could be derived from the process or its products. Liquefaction mechanisms depend upon the solvent-substrate interaction: with creosote oil, pyrolysis mechanisms predominate and lead to integral liquefaction of the wood while with ethylene glycol only fractional liquefaction was possible, apparently as a result of a complex formation between ethylene glycol and cellulose which protects the chain polymeric from being solubilized. 相似文献
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商陆修复镉污染土壤初探 总被引:2,自引:0,他引:2
植物吸收是目前对土壤重金属污染修复最具前景的一种方法.通过盆栽实验,测定生物量、生物浓缩系数、富集浓度等一系列指标,探讨商陆对土壤镉污染的修复能力.结果表明,商陆对土壤中的镉(Cd)有很强的吸收富集能力,且富集浓度与土壤镉浓度成正相关,其富集能力符合超富集植物标准,初步确定商陆是重金属镉的超富集植物.研究结果可为土壤镉污染的植物修复技术提供重要的参考. 相似文献
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Hydrogen-donor solvents such as hydrophenanthrene are the most effective aromatic solvents for the liquefaction of brown coal. The hydrogen-donating ability of the solvent is more important for brown coals than for bituminous coals, because the thermal decomposition and subsequent recombination of the structure of the brown coals occurs rapidly. Three-ring aromatic hydrocarbons are more effective solvents than two-ring aromatics, and polar compounds are less effective solvents with brown coals than with bituminous coals. The thermal treatment of brown coal, accompanied by carbon dioxide evolution at temperatures > 300°C, in the presence of hydrogen-donating solvent did not affect the subsequent liquefaction reaction. However, thermal treatment in the absence of solvent strongly suppressed the liquefaction reaction, suggesting that the carbonization reaction occurred after the decarboxylation reaction in the absence of hydrogen donor. To study the effect of various iron compounds, brown coal and its THF-soluble fraction were hydrogenated at 450°C in the presence of ferrocene or iron oxide. The conversion of coal and the yield of degradation products are increased by the addition of the iron compounds, particularly ferrocene, and the yield of carbonaceous materials is decreased. 相似文献