微管内环己烷氧化反应研究进展

介绍了微管反应器和微管内环己烷氧化反应的特点;详述了微管内环己烷无催化氧化的反应工艺、微管内气液流动情况、反应机理以及微管内壁负载催化剂的环己烷催化氧化反应工艺;指出无催化及内壁涂覆催化剂的微管内环己烷氧化反应在改善反应的安全性、强化气液传质效果和提高催化性能等方面具有较大优势,微管内壁负载纳米金催化剂的反应器形式在环己烷氧化反应中前景看好。     

环已烷液相氧化反应动力学研究进展

本文对环己烷液相催化或无催化氧化制KA油,环己烷均相或非均相一步氧化制己二酸的反应机理、动力学模型及传质与动力学之间的关系进行了综述。最后指出,我国应加强对环己烷液相氧化反应,尤其是反应动力学和传质过程的研究和开发,为我国尼龙66生产装置的完全国产化作必要的技术贮备。同时,对非均相氧化的研究也应引起重视。     

环己烷催化氧化反应器形式的研究

针对金属卟啉催化氧化环己烷工艺的特点,选择鼓泡式反应器、搅拌式反应器和多釜串联搅拌式反应器进行一系列实验,分析了各类反应器形式对氧化产物的影响,确定了环己烷催化氧化反应器的最佳形式。     

DNTF合成反应器的模拟与设计

对DNTF合成氧化反应器进行了模拟和放大设计.根据反应体系的动力学特性和设备的传递特性,对反应器进行基础参数计算,确定了反应器的结构参数:如反应器体积、搅拌方式及转速、传热面积和换热方式等技术参数.将反应动力学模型和反应器热量传递结合起来,计算反应器的放热速率和热负荷,考察和分析反应器的能量和热量平衡,及反应器温度的波...     

用非等温固定床反应器研究多相催化反应宏观动力学

以工业银催化剂上乙烯环氧化反应为模型反应,探讨了用非等温固定床反应器研究多相催化反应宏观动力学的方法。根据不同条件下测得的床层轴向温度分布及反应器出口转化率和收率,用广义高斯—牛顿法对常微分方程组中的动力学参数进行估值,得到了较满意的结果。     

苯酚装置氧化反应器扩能改造

分析了异丙苯液相氧化反应原理及影响因素开始,通过氧化工艺技术的对比,确定了改造工艺技术;利用ASPEN PLUS模拟计算软件,引入了溶氧因子f对氧化反应理想动力学模型进行修正,确定了合理的动力学模型参数;在此基础上,对氧化反应器改造的二塔、三塔、四塔流程进行了比较,确定了最佳的改造方案.     

环己烷液相非催化/催化氧化反应动力学特性比较

分别以不同氧浓度气体及纯氧作为氧源,利用鼓泡塔反应器在1.1 MPa、不同温度、不同气体流量条件下比较了环己烷液相非催化氧化和催化氧化反应特性。通过比较分析,讨论了环己烷液相氧化的链式反应机理。理论分析和实验数据表明,环己烷液相催化氧化反应诱导期短,其表观速率与环己烷浓度和氧气浓度都为一级;而非催化氧化反应诱导期长,是由烃直接氧化引发过程控制,只有当过氧化氢积累到一定浓度以后,过氧化物分解产生自由基速率变得显著,反应才表现出自催化反应特征。而在催化剂存在的情况下,环己基过氧化氢分解非常迅速,环己基过氧化氢浓度在整个反应过程中稳定在一个很低的水平,反应由氧化生成酮的链传递反应过程控制。     

国内外化学工程文献摘要

<正>83045 环己烷自催化饭化的反应动力学模拟——A.K·Suresb等人,AIChE J .3.[1],63(1988). 研究了环己烷自催化氧化体系的动力学及动力学与传质的相互作用     

微反应器内甲苯气固催化氧化反应动力学

微通道反应器具有优良的传热、传质性能，能有效避免催化剂床层内热点的形成，为研究强放热反应动力学提供有利条件。开展了微反应器内的V2O5/TiO2催化剂上的甲苯气相选择氧化动力学研究，在简化反应网络的基础上建立了动力学模型，并给出动力学参数。该模型能较好地反映和预测较宽的反应条件范围内的甲苯气固相催化氧化反应转化率及产物分布，为优化操作条件提供依据。     

接触氧化有机污染物降解动力学模型研究

以黑石子垃圾渗滤液强化预处理-生物接触氧化处理技术为依托,针对其处理效果的局限性,设计了预处理-生物接触氧化反应器,并进行生物接触氧化反应器试验及其有机物降解动力学模型研究,旨在优化运行参数,提高渗滤液处理效能.得出以下结论:生物接触氧化反应器系统处理效能好,出水水质较黑石子垃圾渗滤液处理工艺得到大幅度的改善;对接触氧化反应器垃圾渗滤液有机物降解生化反应过程进行量化研究,得到微生物生长动力学模型:1/θc=0.9187YOA·q-0.0025;根据生物接触氧化内基质消耗过程的物料平衡,得到生物接触氧化反应器处理垃圾渗滤液有机污染物生物降解的动力学模型为q=1.09S/(10230 S),以此指导反应器的优化控制、设计与应用.     

气固相光催化氧化反应动力学分析

对气固相光催化氧化基元反应进行了动力学分析 ,建立了简单适用的动力学模型 .理论分析表明 ,在较低的紫外光强度下 ,光催化反应速率与光强成正比 ;在较高的光强度下 ,速率与光强的平方根成正比 ;在极高光强度下 ,速率与光强无关 .因此将光催化反应简单分解为 3个速率步骤 ,即光子传递步骤、表面作用步骤、扩散步骤 .设计了新颖的气固相光催化反应器 ,采用三氯乙烯 (TCE)为模拟污染物 ,实验结果验证了气固相光催化反应存在光子传递和表面作用控制步骤     

Catalytic reduction of NOx over Cu/ZSM-5 catalyst

Catalytic decomposition of NO on Cu/ZSM-5 catalyst was carried out in tubular fixed-bed reactor at atmospheric pressure. The influence of temperature and flow rate on the reaction rate was investigated. The kinetic model of reaction was proposed and compared with the literature results. The formation of NO₂ during the catalytic decomposition of NO was also monitored. Therefore, additional experiments were performed aimed at examining the kinetics of NO oxidation under the same reaction conditions. Both kinetic models were used to develop the reactor model and to describe quantitatively the behavior of the overall reaction system. Satisfactory degree of correlation between experimental data and values predicted by reactor model has been achieved.     

THE ELUCIDATION OF THE KINETICS AND MECHANISMS OF THE CATALYTIC OXIDATION OF TRACE AMOUNTS OF DIMETHYL ETHER IN OXYGEN BY TRANSIENT PHENOMENA

Thermal desorption experiments with different heating schemes were used to study the kinetics and mechanisms of the catalytic oxidation of dimethyl ether (DME) on supported Pt catalysts. The experimental apparatuses were fully automated by using a microcomputer control system. This made possible direct evaluations of several key kinetic parameters as well as long-term evaluations of the catalysts. The oxidation of DME catalyzed by Pt/SiO₂-Al₂O₃, catalyst has been shown to involve the chemisorption of DME on the support and the chemisorption of oxygen on Pt metal sites. The surface reaction between chemisorbed DME and oxygen was found to be the rate-determining step under the experimental conditions investigated. The proposed reaction mechanism using the kinetic parameters estimated from the thermal desorption experiments predicts the experimental results very well. Acetylene was found to have a promotional effect for the reaction. It is believed that carbon from acetylene plays a key role in this reaction enhancement.     

反应条件对石蜡深度氧化制取二元酸的影响

研究了石蜡液相深度氧化过程中氧吸收量与氧化蜡组成变化的关系。结果说明,深度氧化蜡绝大部分是由多官能团酸组成,其官能团除羧基为主外,次为酯基,其量为羧基的一半,羰基较少,而羟基几无。C_4～C_（10）二元酸在氧化醋酸价为250毫克KOH/克左右时开始有明显的含量,并且随着氧化深度的增加而含量迅速增加。在适宜的催化剂和较好的气液接触情况下,石蜡能否快速定向深度氧化的关键在于恰当的选择温度和氧分压;使整个反应过程中氧化尽可能在化学动力学控制范围内进行,减少扩散因素的影响。试验结果表明,氧化蜡的酯价/酸价比值可作为反映氧扩散速度是否满足氧化动力学速度的需要,也可以估计氧化所能达到的最高酸价。氧化过程中物料收率变化的规律说明,在反应后期氧化蜡收率的显著降低,与此时CO_2和冷凝水相的生成速度迅速增加有关。氧化至酸价400以上后,C_4～C_（10）二元酸的收率最高可达40％（对原料石蜡）。从色谱分析结果得知,在C_4～C_（10）的单体二元酸分布中,一般皆以丁二酸为最多,次为戊二酸,并且C_4～C_5和C_6～C_（10）二元酸的收率相近。     

1,2-环己二醇合成己二酸的氧化动力学

以H_2O_2为氧化剂,磷酸为助剂,采用初始浓度法研究了钨酸催化过氧化氢氧化1,2-环己二醇合成己二酸的氧化动力学,建立动力学模型,得到了反应动力学方程。实验结果表明,1,2-环己二醇的反应级数为0.98,H_2O_2的反应级数为0.30,反应的活化能为46.92 k J/mol,指前因子为9.48×10~4 L~(0.28)/(mol~(0.28)·min)。通过实验验证氧化动力学方程,计算值和实验值的平均相对误差为0.2%,两者基本吻合。     

Selection of a diesel fuel surrogate for the prediction of auto-ignition under HCCI engine conditions

Homogeneous charged compression ignition (HCCI) is a promising combustion concept able to provide very low NO_x and PM diesel engine emissions while keeping good fuel economy. Since HCCI combustion is a kinetically controlled process, the availability of a kinetic reaction mechanism to simulate the oxidation (low and high temperature regimes) of a diesel fuel is necessary for the optimisation, control and design of HCCI engines. Motivated by the lack of information regarding reliable diesel fuel ignition values under real HCCI diesel engine conditions, a diesel fuel surrogate has been proposed in this work by merging n-heptane and toluene kinetic mechanisms. The surrogate composition has been selected by comparing modelled ignition delay angles with experimental ones obtained from a single cylinder DI diesel engine tests. Modelled ignition angle results are in agreement with the experimental ones, both results following the same trends when changing the engine operating conditions (engine load and speed, start of injection and EGR rate). The effect of EGR, which is one of the most promising techniques to control HCCI combustion, depends on the engine load. High EGR rates decrease the n-heptane/toluene mixture reactivity when increasing the engine load but the opposite effect has been observed for lower EGR rates. A chemical kinetic analysis has shown that the influence of toluene on the ignition time is significant only at low initial temperature. More delayed combustion processes have been found when toluene is added, the dehydrogenation of toluene by OH (termination reaction) being the main kinetic path involved during toluene oxidation.     

Kinetic and reaction mechanisms of calcium bisulfite catalytic oxidation

In this paper, the oxidation of calcium bisulfite in the presence of ferrous ions as a catalyst is studied in a laboratory scale apparatus at a fixed oxygen partial pressure (21.3 kPa) and at a temperature of 45 °C. The analysis of the experimental results, carried out by using the theory of mass transfer with chemical reaction, indicates that the slow reaction regime has been explored, and the transition from the kinetic to the diffusional subregime identified. A kinetic analysis allows to develop a reaction rate equation, assuming that the bisulfite oxidation in the presence of ferrous ions follows a parallel reaction mechanism; the resulting overall reaction rate has been found to be of first order with respect to ferrous ion concentration and of three halves with respect to bisulfite concentration. Moreover, the catalytic effect of ferrous ions has been compared with that of manganese ions previously studied, showing that ferrous is a catalyst more active than manganese.     

A multi-step kinetic model for phenol oxidation in high-pressure water

A kinetic model for the oxidation of phenol in high-pressure water has been developed and compared with experimental data taken from literature. The model assumes a chain reaction propagated by O^? and OH^?. Production of the hydroxyl radical by the reaction of atomic oxygen and water induces a chain-branching effect, which is particularly effective at low temperatures and high pressures. The proposed model gives a fair correlation of the experimental data in the whole examined temperature and pressure range and appears significantly better than a simpler, power-law kinetic model. The relibility of the model is strengthened by the consideration of values obtained for the kinetic parameters (in particular for the activation energies) which compare well with the literature.     

异丙苯液相氧化反应动力学研究

本文研究了在半间歇操作条件下,在100°—130℃的温度范围内,采用异丙苯氢过氧化物为引发剂的异丙苯液相空气氧化反应动力学.根据烃类氧化的链式自由基反应机理以及对在氧化反应中异丙苯氢过氧化物分解方式的假设,导出该氧化反应在链稳定增长阶段的反应动力学模型.根据所获得的实验结果,确定了异丙苯液相氧化反应及氢过氧化物分解副反应的速率常数、表观活化能及反应速率常数的Arrhenius关系式.由反应动力学模型计算出的异丙苯和它的氢过氧化物浓度与实验结果吻合良好.文中还讨论了在半间歇操作中存在的诱导期以及反应温度对异丙苯转化率和异丙苯氢过氧化物选择率的影响.     

Some kinetic aspects of unsteady-state partial oxidation reactions. Dynamic processes on metal oxide surfaces

It is shown that steady-state kinetic data do not allow the discrimination between the redox and associated mechanisms of the partial oxidation reactions. A discrimination between these mechanisms was performed using transient experiments. The obtained rate expressions are in agreement with experimental kinetic data for catalytic partial oxidation of o-xylene.

An influence of the conjugate oxidation of a catalyst surface on dynamics and kinetics of the heterogeneous catalytic oxidative reactions is considered. Computing simulation of methane oxidative coupling of methane reaction at lowered temperature and elevated pressure has been performed. It showed that the reaction order with respect to oxygen exceeding unity is consistent with the chain branching mechanism of the reaction in the presence of TiSi₂ and TiB₂ and showed the important role of the branching chain cycles in the low-temperature OCM reaction at elevated pressure.