酸对过氧化氢异丙苯热稳定性的影响研究

为研究酸对过氧化氢异丙苯(CHP)热稳定性的影响,利用C600微量量热仪研究了CHP及CHP与不同含量硫酸、乙酸的混合物在空气中受热分解的反应和放热特性,利用Semenov热爆炸模型计算出了自加速分解温度(SADT)。结果表明,与酸以一定比例混合后能够使CHP的起始放热温度、最大放热温度降低,乙酸对其热稳定性的影响更加明显;计算得到25%CHP的SADT为140℃,通过对CHP与不同含量硫酸、乙酸混合物SADT进行比较,发现少量的硫酸和乙酸均能降低CHP的SADT,而CHP与乙酸混合物的SADT更小。     

水和弱酸对过氧化氢异丙苯热危险性的影响

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。     

管式搅拌反应器停留时间分布的数值模拟

对一种新型管式搅拌反应器的停留时间分布(RTD)进行了实验研究,运用商业计算流体力学(CFD)软件FLUENT进行流场模拟及RTD计算,证实管式搅拌反应器的停留时间分布受搅拌转速及入口流量等因素影响,带搅拌装置的管式反应器适当增加转速能使RTD曲线变窄,改善流型和抑制返混;转速过大会使RTD曲线变宽,导致死区的产生,不利于反应器的混合.RTD曲线的数值模拟计算结果与实验结果基本稳合.     

均相茂金属催化剂催化苯乙烯间规聚合中搅拌的作用

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。     

对二甲苯氧化反应器内置导流筒的性能研究

利用CFD技术,模拟高径比为1.5的PX氧化双层搅拌桨反应器增设导流筒的混合特性,得出:反应器内内置适当型式的开槽导流筒,可以限制气体的循环路径,延长气体的停留时间,增强气体的再循环,改善气体和传质系数分布状况。进一步实验研究表明,安装导流筒之后,气含率、传质系数可以提高10%~30%。     

苯乙烯热聚合搅拌反应器的数值模拟

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。     

Novolen聚丙烯工艺中反应器的发展历程

本文从撤热方式和结构设计两方面介绍了Novolen聚丙烯工艺中反应器的发展历程。对于撤热方式,在从淤浆法到气相法聚丙烯工艺的沿革中,其撤热方式均为利用单体作为撤热介质、不断在反应器与冷却系统之间循环。对于反应器结构设计,Novolen工艺始终采用搅拌反应器,但开发了不同型式的搅拌桨以使粉体和催化剂均匀混合,并设计了气体分布器防止死区产生。     

脲醛树脂包覆异丙苯过氧化氢微胶囊的制备及热稳定性

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。     

氢氧化钠催化过氧化氢异丙苯分解研究

捅要：为研究过氧化氢异丙苯（CHP）的热稳定性,本文利用C600微型量热仪对CHP和CHP与NaOH的混合物在空气中受热分解的反应和放热特性进行了实验研究。同时通过GC／MS分析了CHP和不同浓度NaOH混合后的产物组成,并利用气相色谱仪对各产物进行了定量分析,结果得出高浓度氢氧化钠催化CHP分解产物主要是2一苯基一2一丙醇,低浓度时的主要产物是乙酰苯。氢氧化钠催化CHP分解产物的组成与其浓度相关。     

物流分布对板翅式制氢反应器性能的影响

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。     

A Control Strategy for a Chemical Heat Pump Dryer

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.     

Enhancement of Energy Efficiency of a Chemical Heat Pump-Assisted Convective Dryer

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.     

Chemical and adsorption heat pumps: Cycle efficiency and boundary temperatures

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.     

焦炉煤气直接氧化制合成气工艺条件优化

为进一步优化焦炉煤气非预混燃烧直接制备合成气的工艺参数,对焦炉煤气在贫氧条件下发生非预混燃烧的过程进行数值模拟研究,得到了反应器内温度及产物组成分布的详细分布状况.模拟结果表明,反应在靠近氧气入口的区域内发生.从数值模拟的结果来看,反应器壁温对反应结果有非常重要的影响:提高反应器壁温有利于提高合成气的选择性,但是煤气中甲烷的转化率有所降低.因此,反应器壁温是能够控制本工艺总体反应效果的重要参数,工艺优化过程中应该特别注意.     

热变温器系统气固反应器内部的温度特性

以气固反应热变温器系统的反应器为研究对象，通过建立数学模型，计算了反应器内部在反应过程中的温度分布及其随时间的变化，讨论了一些参数对于反应器内部温度分布的影响。结果表明：TC减小、pC增大以及fg减小、ρb增大，使反应器内部温升增加、反应器对废热流体的加热功率q增大，而反应器内部的温度不均匀性亦增加。     

尼龙6聚合管内微分发热量与温度分布

<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。     

Radiative transfer in a solar chemical reactor for the co-production of hydrogen and carbon by thermal decomposition of methane

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.     

Acidic Montmorillonite/Cordierite Monolithic Catalysts for Cleavage of Cumene Hydroperoxide

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...