共查询到18条相似文献,搜索用时 156 毫秒
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为研究水和弱酸对过氧化氢异丙苯(CHP)热危险性的影响,利用C600微量热仪研究了CHP及CHP与不同含量水、不同含量弱酸、不同pH值弱酸的混合物在空气中受热分解的反应和放热特性,根据实验数据得出了相应的动力学和热力学参数,利用Semenov热爆炸模型计算出了自加速分解温度(SADT)。结果表明:少量的水和弱酸都能够使CHP的起始放热温度、最大放热温度、活化能降低;弱酸的pH值对CHP的热危险性也有影响,pH值越低,CHP的热危险性越大;计算得到CHP的SADT为84℃,通过对CHP及CHP与不同含量水、弱酸和不同pH值弱酸混合物SADT进行比较,发现少量的水和弱酸均能降低CHP的SADT,弱酸的pH值对SADT也有影响,pH值越低,CHP与弱酸混合物的SADT越小。 相似文献
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均相茂金属催化剂催化苯乙烯间规聚合中搅拌的作用 总被引:2,自引:0,他引:2
在不同搅拌型式的聚合反应器中使用均相茂金属催化剂(Cp^*Ti(OR)3/MAO/TIBA催化苯乙烯本体间规聚合。研究搅拌桨型式、反应器以及搅拌速度对聚合物形态以及聚合过程的影响,并分析了搅拌、结晶和聚合之间的关系。研究表明,良好的搅拌剪切对避免凝胶、促进粉状间规聚苯乙烯的生成至关重要。聚合动力学的研究表明,搅拌转速不仅能影响聚合物的颗粒形状,也能通过改变聚合物原生晶的结晶速率从而影响聚合速率。 相似文献
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《化学工程》2015,(12):67-72
为了解聚合反应过程的传热规律和反应现象,以苯乙烯热聚合搅拌反应器为研究对象,通过计算流体力学(CFD)方法对苯乙烯热聚合反应的动力学模型进行耦合,建立该反应器的三维非稳态模型。通过UDF添加组分输运方程源项和能量方程源项,研究强放热反应体系热点分布及发展历程。重点考察物料黏度、搅拌速度对聚合反应器内速度场和温度场分布的影响。结果表明:物料黏度的增加,阻碍了远离搅拌桨区域内物料的对流传热,易在反应器顶部形成局部高温;提高搅拌速度可以使反应器内温度分布更加均匀,但会加剧聚合反应,造成反应器内平均温度升高。研究结果为揭示典型化工过程系统热失控的演化机理,预防热失控反应的发生提供了理论依据。 相似文献
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针对可预涂厌氧胶贮存稳定性差的问题,从过氧化物微胶囊颗粒控制和热稳定性出发,以异丙苯过氧化氢(CHP)为芯材,脲醛树脂(PUF)为壁材,制备脲醛树脂包覆CHP微胶囊。研究了稳定剂用量、反应时间、搅拌速率和升温速率等工艺条件对微胶囊颗粒形态的影响。结果表明:稳定剂用量和反应时间需要大于一临界值后才能得到形貌规整的微胶囊;升温速率越快,颗粒越早稳定;只要反应速率合适,搅拌速率对颗粒大小的影响较小。在相同温度下,脲醛树脂包覆CHP微胶囊的热失重远低于CHP;制备的脲醛树脂包覆CHP微胶囊稳定性优于市售国外包覆CHP型微胶囊,大大提高了可预涂厌氧胶的贮存稳定性。 相似文献
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物流分布对板翅式制氢反应器性能的影响 总被引:1,自引:0,他引:1
建立了板翅式制氢反应器中的三维数学模型,并采用此模型对反应器内部的温度分布进行了数值计算,并且和实验结果相结合,对不同方式的燃烧气流分布的效果进行分析。计算和分析结果均表明:燃烧气流分布均匀与否对反应器性能的影响较大,通过改进气体分布可以有效地改善反应器内部的温度分布及反应性能。 相似文献
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Hironao Ogura Tstsuya Yamamoto Yasufumi Otsubo Hiroki Ishida Hiroyuki Kage Arun S. Mujumdar 《Drying Technology》2005,23(6):1189-1203
This article presents results of an experimental investigation on the controllability of hot air production using a pair of chemical heat pumps (CHP). The objective of this study is to determine how a CHP-assisted batch dryer can be operated effectively. The CHP uses the well-known CaO/H2O/Ca(OH)2 hydration/dehydration reaction, which is reversible. The hot air temperature can be controlled by adjusting the reactor temperature, and pressure, as well as thermal power supplied to it. It is shown that hot air can be produced in both the heat storage and heat release steps of the CHP. 相似文献
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In earlier studies we have shown by simulation and experimental studies that the proposed chemical heat pump (CHP) unit can be used to recover waste heat from dryers and reuse it by storing and releasing heat with upgrading the temperature or by dehumidification. However, the final thermal energy production efficiency of the CHP for drying was found to be low. In this paper we present experimental results to demonstrate the potential for improved heat-recovery/storage and the heat-release/production of hot dry air for batch drying applications using the heat enhancement mode of the CHP. A new laboratory scale experimental CHP dryer system was built utilizing the calcium oxide/calcium hydroxide hydration/dehydration reversible reaction. The aim of this study is to improve the efficiencies of the heat recovery from heat source in the heat-storage step and the hot dry air production in the heat-release step of the CHP for heating up the air to around 100°C. The results of this experimental study utilizing a new reactor design showed that the shallow reactor/heat exchanger could accomplish 94% chemical heat storage and produce 100°C air at better than 75% efficiency for the reaction heat by controlling the preheating condition. The reaction conversion reached 90% in these experiments. The proposed CHP-assisted convective dryer system is found to be energy-efficient over a wide temperature range of industrial interest. 相似文献
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Yu. I. Aristov 《Theoretical Foundations of Chemical Engineering》2008,42(6):873-881
The efficiency of an ideal three-temperature (3T) cycle of a chemical heat pump (CHP) is considered. For a reversible CHP
3T cycle, the maximal efficiency can be determined using the ratio of the heat of evaporation of the working fluid and the
heat of the chemical reaction or using the boundary temperatures of the cycle. The boundary temperatures of the reversible
CHP cycle are not independent variables relative to each other. As they are related by the Clausius-Clapeyron equation for
the equilibrium of the pure fluid and by the van’t Hoff equation for the chemical reaction, the choice of one of these temperatures
completely determines the two others. Comparison of the efficiencies of the CHP cycle and the cycle of an adsorption heat
pump (AHP) shows that the CHP efficiency can theoretically reach the Carnot-cycle efficiency whereas the AHP efficiency is
always less than the Carnot-cycle efficiency because of the generation of entropy due to the transfer of heat to (from) the
adsorber at a finite temperature difference. The minimal temperature of the external heat source needed for the operation
of the CHP (AHP) cycle, the minimal evaporator temperature, and the maximal condenser temperature are calculated. These temperatures
are determined for CHP (AHP) applications such as heating, air conditioning, ice production, and deep freezing in different
climatic zones.
Original Russian Text ? Yu.I. Aristov, 2008, published in Teoreticheskie Osnovy Khimicheskoi Tekhnologii, 2008, Vol. 42, No.
6, pp. 676–685. 相似文献
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尼龙6聚合管内微分发热量与温度分布 总被引:3,自引:0,他引:3
<正>1引言 尼龙6是合成聚酚胺生产中最重要的产品之一[1],目前工业上多数采用水解聚合。本文涸绕尼龙6聚合反应工程开发的一系列工作都是为这一技术路线国产化提供理论基础。近卫0年来,尼龙6聚合的各种主、副反应精确的动力学数据已有报道[2,3],目前的重点已转向工业化生产反应器中各种物理过程的模拟,诸如传热、流动、混合、停留时问分布、蒸发脱水以及过程优化控制等领域。 相似文献
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David Hirsch 《Chemical engineering science》2004,59(24):5771-5778
Radiation heat transfer in a solar chemical reactor for the co-production of hydrogen and carbon by thermal decomposition of CH4 is analyzed by the Monte Carlo ray-tracing method. The solar chemical reactor features a vortex flow of CH4 confined to a cavity and laden with carbon particles that serve simultaneously as radiant absorbers and nucleation sites for the heterogeneous decomposition reaction. The reactor is treated as a 3D non-isothermal non-gray absorbing-emitting-scattering gas/particle suspension directly exposed to concentrated solar irradiation. The analysis includes coupling to conduction/convection heat transfer and chemical kinetics. Calculated temperature distribution and chemical conversion are compared with the experimentally measured values obtained with a 5 kW prototype reactor tested in a solar furnace. 相似文献
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In this work, a series of acidic montmorillonite/cordierite monolithic catalysts were prepared by a coating method using silica sol as the binder. The morphology and structure of the acidic montmoril o... 相似文献