共查询到18条相似文献,搜索用时 171 毫秒
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为开发多段绝热床生物质乙醇脱水制乙烯反应工艺,在Φ10 mm等温积分反应器中以自研发的氧化铝为催化剂研究了生物乙醇脱水制乙烯反应动力学。实验在排除内外扩散的影响的条件下,考察了反应温度、反应空速和水醇比对反应的影响,建立了生物质乙醇脱水制乙烯的半理论半经验的幂函数本征动力学模型。模型方程具有统计意义上的可靠性,并与实验结果吻合良好。 相似文献
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给出了低浓度乙烯和苯在ZSM-5型分子筛催化剂上的宏观动力学方程。建立了中试固定床反应器模型。模型值与中试结果相一致。化较了单段绝热床、等温床和多段绝热床反应器行为。结果表明:在达到乙烯95%转化率时,苯生成乙苯和乙烯生成乙苯的选择性为等温床要化单段绝热床好;四段绝热床可达到与等温床相当的指标。考虑到绝热床投资少,操作简单,可变性强,四段绝热床反应器应该是首选的反应装置。 相似文献
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介绍了采用浅床层固定床反应器,在近似工业条件下对AKZO公司开发的FPC-2LD催化剂进行了氧气法乙烯氧氯化制二氯乙烷的本征动力学研究,用多元线性回归数学模型对实验数据进行计算,建立了该催化剂的主反应动力学方程式。 相似文献
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在固定床反应器中考察了USY(超稳Y分子筛)和过渡金属改性USY催化低浓度乙醇脱水制乙烯反应,并通过BET,XRD和NH3-TPD等手段对改性前后的催化剂进行表征.结果表明,Co/USY的催化反应性能较好.当硝酸钴浸渍液质量分数为3%时,催化反应效果最好,乙醇转化率达到93.2%,乙烯选择性达到95.7%.Co/USY催化低浓度乙醇脱水制乙烯反应中乙烯的选择性对反应温度敏感,乙烯选择性由220℃的24.0%骤然提高到250℃的95.7%,在280℃时乙烯选择性达到100%.并且考察了Co/USY的初期稳定性,发现在反应102 h后催化剂仍具有良好的活性. 相似文献
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给出了低浓度乙烯和苯在ZSM-5型分子筛催化剂上的宏观动力学方程,建立了中试固定床反应器模型,模型值与中试结果相一致,比较了单段绝热床,等温床,等温床和多段绝热床反应器行为,结果表明:在达到乙烯95%转化率时,苯生成乙苯和乙烯生成乙苯的选择性为等温床要比单段绝热床好;四段绝热床可达到与等温床相当的指标,考虑到绝热床投资少,操作简单,可变性强,四段绝执档反应器应该是首选的反应装置。 相似文献
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在排除内外扩散影响的条件下,采用微型等温固定床反应器对工业化氧化铝催化剂上乙醇脱水的动力学行为进行了实验研究.建立了工业氧化铝上乙醇脱水的半经验动力学模型,采用高斯-牛顿方法对实验结果进行拟合.统计检验结果表明,所建模型很好地吻合了实验数据,是适宜和可行的. 相似文献
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乙醇脱水反应的动力学研究 总被引:2,自引:0,他引:2
在管式固定床反应器中,采用改性的分子筛催化剂,在温度195~220℃、乙醇浓度30~70 wt%、乙醇液时空速0.08~0.17 mol/g-cat./h的范围内,对乙醇脱水反应的本征动力学进行了研究。动力学研究结果表明,在实验条件范围内,乙醇脱水生成乙烯和乙醚的反应属于平行反应,符合Langmuir-Hinshelwood机理模型,表面反应为速率控制步骤。 相似文献
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Ethanol dehydration to ethylene is tested on industrial alumina, a support for hydrotreating catalyst IK-GO-1 (AOIK-GO-1), sorbents AN-2N and AOK-63-22, and catalyst AOK-78-59. Activity is measured in a plug-flow reactor in the temperature range of 375–400°C at a contact time of 0.3 s, and the effect of the process temperature on the conversion of ethanol and the selectivity toward target and secondary products is determined. A correlation between the specific activity and mass fraction of sodium is found for samples with homogeneous phase composition. It is shown that the activity of the investigated industrial catalytic systems based on alumina in the dehydration of ethanol to ethylene changes in the order AOIK-GO-1 > AN-2N > AOK-63-22 > AOK-78-59. 相似文献
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Application of heteropoly acid catalyst in an inert polymer membrane catalytic reactor in ethanol dehydration 总被引:2,自引:0,他引:2
The ethanol dehydration reaction was carried out in an inert membrane catalytic reactor. 12-Tungstophosporic acid as a catalyst and polysulfone as an inert membrane were used in this study. Ethanol conversion and ethylene selectivity were remarkably enhanced in comparison with those in a fixed-bed reactor under the same reaction condition. 相似文献
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V-P/HZSM-5催化乙醇流化床脱水制乙烯 总被引:4,自引:0,他引:4
分别采用P、V和V-P改性HZSM-5,在自行设计的流化床装置上评价其对乙醇脱水制乙烯的催化性能。采用X射线荧光光谱(XRF)、X射线粉末衍射(XRD)、吡啶吸附红外光谱(Py-IR)、比表面积分析(BET)和X射线光电子能谱(XPS)等手段对催化剂的物化性能进行表征,同时考察了不同催化剂制备条件和催化反应条件等工艺因素对催化剂性能的影响。结果表明,V-P复合改性HZSM-5比P和V单独改性的催化效果好,在P和V原子比为7.5、焙烧温度300 ℃、反应温度220 ℃、乙醇进样流速0.1 mL·min-1和催化剂用量3.0 g条件下,乙醇的转化率和乙烯的选择性分别高达96.9%和93.5%,具有稳定的初期活性。同时,该催化剂对低浓度乙醇的脱水反应表现出较佳的催化活性。 相似文献
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Ethylene production from petroleum or natural gas is an energy intensive process. Bio-ethanol catalytic dehydration to ethylene is an attractive alternative for oil based ethylene. Catalytic dehydration conversion of bio-ethanol to ethylene using HZSM-5 modified by 3 wt% rare earth metal (lanthanum) was carried out in a laboratory bioreactor. The physicochemical properties of the catalyst were characterized. The stability test showed that ethanol conversion and selectivity over this catalyst could be maintained above 98% for more than 950 h. The regenerated catalyst also displayed high reactivity and stability of up to 830 h can be obtained. The effects of temperature, liquid hourly space velocity, particle size of catalyst, and bio-ethanol partial pressure on products formation rate were investigated. The external and internal diffusion resistances were eliminated and the kinetic control range was identified. An apparent kinetics model was used to describe the dehydration reaction of ethanol over 3 wt% La-HZSM-5 catalyst, and the kinetic parameters were determined. 相似文献
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In earlier studies the behavior of single catalyst pellets of Pd on alumina has been investigated for the reaction of acetylene in an ethylene stream with hydrogen. Particle runaway, temperature over‐ and undershoots and chemically induced temperature oscillations have been observed. After that, the steady state and dynamic behavior of an adiabatic packed bed reactor has been studied experimentally. Temperature profiles of both the gas and solid phase as well as local temperature differences between the two phases were measured. Also here the temperature in the reaction zone exhibited oscillatory behavior. On addition of CO, the oscillations disappeared and the selectivity improved. For a given set of operating conditions, there existed a relatively small range of CO contents with good selectivity and satisfactory conversion. This range depends strongly on the inlet temperature. The dynamic response of the reactor to changes in the CO content showed a considerable wrong‐way behavior. This high sensitivity to fluctuations in the CO content, found for our experimental reactor, indicates a probable cause for a thermal runaway in industrial practice. Recommendations for a stable reactor operation are given. 相似文献
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以La改性氧化铝为催化剂,在模拟绝热固定床反应器中考察工艺条件对甲醇气相脱水制二甲醚反应的影响。结果表明,甲醇进料温度210℃时,甲醇脱水反应剧烈,绝热温升约130℃。催化剂床层热点温度低于380℃时,二甲醚选择性大于98%,过高温度产生大量副产物甲烷。反应压力对反应影响甚微。在甲醇进料温度240℃(热点温度370℃)、甲醇进料空速1.5 h-1和反应系统压力为50 k Pa条件下,甲醇转化率大于84%,二甲醚选择性大于98.5%,连续运转2 000 h,催化剂无明显失活迹象。 相似文献
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Very high ethylene selectivity values approaching 100% and very high ethanol conversion values approaching 85% were obtained in dehydration of ethanol over a new W-silicate-based nanocomposite catalyst having both meso and macropores and containing a W/Si atomic ratio of 0.85. Silicotungsticacid was successfully incorporated into the catalyst structure following a one-pot hydrothermal synthesis procedure. This catalyst is highly stable and does not loose activity in polar solvents and it has a sufficiently high surface area for catalytic applications. Calcination temperature of the catalyst was found to have a very significant effect on the catalyst structure and also on its catalytic performance in ethanol dehydration. Maximum selectivity of the second major reaction product diethylether was obtained as 0.7 at 200 °C, with the catalyst which was calcined at 400 °C. Very high ethylene and diethylether yield values obtained in this study at different reaction conditions are highly promising for the production of petrochemicals from ethanol. 相似文献