排序方式: 共有79条查询结果,搜索用时 31 毫秒
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昭通褐煤的热解提质及其对气化反应性能的影响 《燃料化学学报》2016,44(8):904-910
为了对储量相对丰富的昭通褐煤进行合理有效的分级转化利用,采用固定床程序升温热解的方法研究了不同温度下煤的热解行为,借助GC-MS和拉曼光谱对所得焦油和煤焦进行了表征分析,并在850℃下对不同热解温度制得的煤焦进行了水蒸气等温气化特性评价。结果表明,热解温度为700℃时,热解气体有效组分(H_2、CO、CH_4)的累积物质的量占总释放量的70%,此温度下热解气低位热值增长速率最快(以500℃下热解气低位热值为基准计算,其值为90%);酚类化合物在500-700℃大量生成析出,而温度高于700℃时,酚类化合物的分解反应加剧。不同热解温度下所制煤焦的表观气化反应速率随热解温度的升高不断降低,气化产物中CO_2与CO的物质的量逐渐升高,700℃热解制得的煤焦在水蒸气气氛下气化所得合成气中有效组分H_2与CO的比率最高。 相似文献
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Duarte LC Carvalheiro F Lopes S Neves I Gírio FM 《Applied biochemistry and biotechnology》2008,148(1-3):119-129
Yeast single-cell protein and yeast extract, in particular, are two products which have many feed, food, pharmaceutical, and
biotechnological applications. However, many of these applications are limited by their market price. Specifically, the yeast
extract requirements for culture media are one of the major technical hurdles to be overcome for the development of low-cost
fermentation routes for several top value chemicals in a biorefinery framework. A potential biotechnical solution is the production
of yeast biomass from the hemicellulosic fraction stream. The growth of three pentose-assimilating yeast cell factories, Debaryomyces hansenii, Kluyveromyces marxianus, and Pichia stipitis was compared using non-detoxified brewery’s spent grains hemicellulosic hydrolyzate supplemented with mineral nutrients.
The yeasts exhibited different specific growth rates, biomass productivities, and yields being D. hansenii as the yeast species that presented the best performance, assimilating all sugars and noteworthy consuming most of the hydrolyzate
inhibitors. Under optimized conditions, D. hansenii displayed a maximum specific growth rate, biomass yield, and productivity of 0.34 h−1, 0.61 g g−1, and 0.56 g l−1 h−1, respectively. The nutritional profile of D. hansenii was thoroughly evaluated, and it compares favorably to others reported in literature. It contains considerable amounts of
some essential amino acids and a high ratio of unsaturated over saturated fatty acids. 相似文献
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本文在Feenstra的要素连续统模型基础上,引入普遍技术水平和配套产业发展水平因素,提出了发展中国家加工贸易产业升级的理论模型。利用1992-2007年13个发展中国家的面板数据进行计量分析之后,我们发现,FDI流入、配套产业发展水平和普遍技术水平的提高都会对发展中国家加工贸易的产业升级产生正向影响,其中,配套产业发展水平的提高起到最主要的推动作用。 相似文献
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萃取耦合化学转化法提质生物油油溶相的研究 总被引:1,自引:0,他引:1
采用萃取耦合化学转化技术对生物油油溶相进行了提质研究。将稻壳快速裂解油加入适宜水使其自然分为水溶相和油溶相。以正丁醇为萃取剂和转化剂,通过在线萃取将油溶相中的酸、醛、酮等可萃物不断萃取出来,再经酯化、缩醛化反应,转化为相应正丁醇的酯、缩醛和半缩醛等。与生物油直接酯化提质相比,萃取耦合化学转化法可以显著抑制提质过程中的结焦问题,降低了提质油相的含水量和酸值,提高了其热值和可挥发性。此外,还考察了油溶相预氧化和预还原对萃取耦合化学转化提质的影响。结果表明,预氧化后可将油溶相中的醛类转化为酸,再经酯化转化为稳定性好的酯类,提质后的油品水含量低于4%,热值高于30 MJ/kg,酸值低于2 KOH mg/g,并且结焦率为零。 相似文献
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水热裂解开采稠油技术研究的进展 总被引:20,自引:1,他引:20
从水热裂解反应、催化作用下的水热裂解反应、反应机理及水热裂解开采稠油现场应用实验等四个方面综述了国内外水热裂解开采稠油技术的研究进展。并对此技术的研究成果及未来发展进行了探讨,认为水热裂解开采稠油技术具有很高的潜在价值,是未来经济高效开采稠油的新途径。当前水热裂解开采稠油技术的主要研究方向是深入研究高温水的特性及其作用;对更多稠油中可能参与水热裂解反应的不同组分,选用合适的模型化合物进行模拟实验或其它方法,建立这些组分的反应热力学和动力学模型库;然后,根据具体稠油中所含的组分,设计水热裂解反应的路线,选择合适的催化剂,促使反应向稠油改质降粘的方向进行。其中,最关键的还是针对不同稠油研制成本低、活性和选择性高、反应条件宽的催化剂,并筛选或研制协同效果好的助剂,进而研究催化剂及其助剂在油层中与稠油作用的机理,设计合理的现场实施技术和工艺。 相似文献
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固体酸改质生物油的研究 总被引:12,自引:0,他引:12
利用乙酸和乙醇生成乙酸乙酯的酯化反应为模型反应,筛选得到催化活性最好的固体酸催化剂40%SiO2/TiO2SO42-。 在一定的反应条件下,添加固体酸催化剂和溶剂,生物油的品质得到提高,热值提高了50.7%,运动黏度降低到原来的10%,密度降低了22.6%。生物油改质前后的GC MS分析表明,固体酸可以将生物油中含有的有机羧酸转化为酯类,如甲酸酯、乙酸酯等,使生物油中的羧酸组分发生了催化酯化反应,改善了生物油的品质,生物油物理化学性能得到明显的提高。3A分子筛对生物油的脱水作用不显著,对酸性、密度、黏度等方面影响较小。 相似文献
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Dr. Senthil Subramaniam Dr. Mond F. Guo Tanmayi Bathena Michel Gray Dr. Xiao Zhang Abraham Martinez Dr. Libor Kovarik Dr. Konstantinos A. Goulas Dr. Karthikeyan K. Ramasamy 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(34):14658-14665
Ethanol can be used as a platform molecule for synthesizing valuable chemicals and fuel precursors. Direct synthesis of C5+ ketones, building blocks for lubricants and hydrocarbon fuels, from ethanol was achieved over a stable Pd-promoted ZnO-ZrO2 catalyst. The sequence of reaction steps involved in the C5+ ketone formation from ethanol was determined. The key reaction steps were found to be the in situ generation of the acetone intermediate and the cross-aldol condensation between the reaction intermediates acetaldehyde and acetone. The formation of a Pd–Zn alloy in situ was identified to be the critical factor in maintaining high yield to the C5+ ketones and the stability of the catalyst. A yield of >70 % to C5+ ketones was achieved over a 0.1 % Pd-ZnO-ZrO2 mixed oxide catalyst, and the catalyst was demonstrated to be stable beyond 2000 hours on stream without any catalyst deactivation. 相似文献
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