利用化学反应的多定态特性筛选动力学模型

以CO在铂催化剂上发生的催化氧化反应为例,以L-H机理和E-R机理为基础,建立了该催化反应的5种动力学模型。利用化学反应网络理论,并依据该反应的多定态特性,对5种可能的动力学模型进行了筛选。筛选结果表明：根据L-H机理得到的模型对应的反应网络能够出现多定态现象,根据E-R机理得到的模型对应的反应网络则无法出现反应体系的多定态现象,因此,L-H机理更为接近CO在铂催化剂上催化氧化的真实反应机理,这与文献结论吻合,证明了利用反应的多定态特性筛选催化反应动力学模型的可行性。     

单颗粒催化剂多定态特性的理论分析

借助于奇异理论和突变理论,本文对单颗粒催化剂的多定态特性进行了分析。得到了反应为一级不可逆放热反应时系统定态模型方程解的结构以及可能具有的歧化图型式;对非一级反应系统,利用区域搜索算法得到了其系统定态模型方程突变集合在操作参数平面上的投影图,分析了反应动力学表达式及动力学参数的变化对体系多定态特性的影响。     

MSMPR连续结晶器的多定态

对混合悬浮混合排料(MSMPR)连续结晶器的定态方程组进行了剖析,应用非线性方程组的延拓求解法,求得了定态方程组的分岔图,即MSMPR连续结晶器状态参数与操作参数的依赖关系.利用分岔理论对MSMPR连续结晶过程的定态数目及相应的参数范围进行了预测,导出了连续结晶过程存在多定态或唯一定态的判据。该判据仅与过程的动力学参数和操作参数有关,而与过程的状态参数无关。最后应用Routh-Hurwitz准则,确定了连续结晶过程各定态的稳定性。     

全混流反应器的定态操作点的讨论

从全混流反应器的热稳定性的角度讨论了全混流反应器操作点的选择问题，分析了各定态操作点的稳定性。指出应选择稳定的定态点作为操作点，当条件限制了选择范围时，可通过改变传热能力，介质温度达到定态操作点条件的目的。     

在铂催化剂上-氧化碳氧化反应的多定态特性

对铂催化剂上一氧化碳氧化反应的多定态特性进行了实验研究,借助于奇异理论和突变理论,对实验结果进行了分析,找出了系统可能存在的定态数目,并预测出在定态数目不同的操作参数区域内,描述系统状态变量与操作参数的分岔图型式,最后,尝试利用系统的多定态特性识别反应的动力学模型,取得了满意的效果.     

等温CMSMPR结晶器定态及瞬态特性分析(Ⅰ)存在多定态及发生持续振荡的条件

运用分岔理论 ,对同时发生初级成核和二次成核的等温连续混合悬浮混合排料 (CMSMPR)结晶器的定态特性进行了分析 ,推导了系统存在多定态及发生持续振荡的参数条件 .以结晶过程的物性参数、动力学参数以及操作参数为基础 ,应用非线性方程组的延拓方法分别求解极限点条件方程组及Hopf分岔点条件方程组 ,确定了系统存在多定态及发生持续振荡的参数边界     

全混流反应器的定态操作点的讨论

从全混流反应器的热稳定性的角度讨论了全混流反应器操作点的选择问题，分析了各定态操作点的稳定性。指出应选择稳定的定态点作为操作点，当条件限制了选择范围时，可通过改变传热能力、介质温度达到改善定态操作点条件的目的。     

滴流床反应器的非定态操作

采用蒽醌加氢反应为探针,研究了脉冲流操作、周期性填充和周期性操作3种非定态操作方式对TBR反应器性能的影响.结果表明,在脉冲流区操作TBR的催化剂质量空时收率比滴流区操作提高50%以上,表观动力学研究证实脉冲流区操作TBR蒽醌加氢反应的表观活化能比滴流区操作更接近本征活化能;催化剂与惰性颗粒的交替填充周期性地强化了气液相间传质速率,提高催化剂质量空时收率40%以上;反应器的周期性操作,同时强化气液和液固相间传质速率,改善反应器内的流体力学状况,从而提高反应的空时收率和选择性10%以上.     

SPG聚丙烯装置反应器的定态模拟

针对中国石油辽河石化分公司的聚丙烯生产装置中测量反应器出口参数的仪表不全的缺陷,通过建立并求解定态数学模型,得到出口浆液浓度、反应物出口浓度等一些重要参数的准确值,并结合实际生产工况,对计算结果进行分析,提出一些优化生产的建议。     

化工装置反应能量系统的(火用)传递描述

对反应(能量)系统的描述,焓分析法单讲能的量的利用,火用分析法只作静态描述,只有火用传递法可作动态描述。运用火用传递理论分析,反应系统具有化学火用转换元在系统中起主导作用,各输火用元皆以反应高温火用源为公共火用源,呈放射型并联结构的特点。据此建立的反应系统通用火用传递模型——化学火用转换元与输火用元并联群相串联的串-并联复合结构模型,清楚地显示了模型的结构特点和基本特征。基于反应系统化学平衡、火用平衡方程和传递学原理建立的系统火用传递方程,揭示了系统中计量和过量反应物、生成物,以及杂质等各项火用流变化率的性质及其相互转换或传递的数量关系,由此可获得对反应系统火用传递机理的清晰描述,进而可以作反应系统的火用传递计算和火用传递分析。     

化学清洗在氢化反应系统中的应用

新装置投用前,非常有必要对其进行彻底的的清洗,这是保证整套装置能够顺利开车并生产出合格产品的一个非常重要的前提条件。本文介绍了氢化反应系统在装置改造后进行化学清洗的一个方法。     

微波在化学反应中的应用

针对微波加热在纳米材料制备、有机化学反应、高分子化学反应以及新型炭(碳)材料的制备和加工,特别是在无机纳米粒子改性、聚合物微球合成中的应用进展进行了综述。     

基于WEB的化学反应工程课件的制作

利用网页制作工具FrontPage2 0 0 0和HTML语言以及ActiveX技术制作了反应工程计算机辅助教学课件。该课件具有跨平台性、分布性和高度的互动性。课件可以部署在INTERNET或局域网的服务器上 ,也可以单机运行 ,只要通过InternetExplore就可以浏览课件内容     

反应性双射流中标量输运和化学反应特性

基于OpenFOAM中pimpleFoam求解器对具有二级非平衡基元反应(A+B\stackrel{}{\to }R)的双平行平面射流中流动-化学反应耦合过程进行数值模拟,研究了不同射流口间距下反应物、生成物浓度标量在流场中心线上的产生、消耗和输运行为。首先将反应性单射流模拟结果与前人实验研究和数值模拟结果进行对比,验证了数值算法的精确性。结果表明：(1) 两股射流在准滞止点和混合点的行为直接影响着化学反应。(2) 射流相互作用尺度x_* 可以预测不同射流口间距下反应物和产物的湍流标量统计量。(3) 在Da=0.1且Sc=0.71时,反应物和产物由对流过程主导输运。(4) 反应物和产物浓度脉动之间的联合概率密度分布(joint probability distribution function,JPDF)呈“心形”,其说明反应物A和反应物B的瞬时浓度在时均值时将有利于化学反应的发生。     

Understanding and optimization of chemical reactor performance for bimodal reaction sequences

The relative contributions of heterogeneously catalyzed and homogeneous bulk phase reactions in bimodal reaction sequences have been assessed via 1D reactor simulations. Starting from a reaction network only comprising two parallel, irreversible heterogeneously catalyzed and homogeneous bulk phase steps, complementary consecutive steps were included with the option of being reversible. The final product formed after a minimum number of homogeneous bulk phase reactions is obtained with high yields in continuous flow fixed bed reactors. The products obtained after a higher number of homogeneous bulk phase reactions generally dominate in slurry reactors. Yields of the latter may exhibit an optimum as a function of the catalyst amount in the reactor. The adsorption enthalpies of the intermediates in the reaction network critically determine the position and shape of this maximum. The reversibility of the homogeneous bulk phase steps provides specific opportunities to tune the product yields in bimodal reaction sequences. © 2016 American Institute of Chemical Engineers AIChE J, 63: 111–119, 2017     

The chemical master equation approach to nonequilibrium steady-state of open biochemical systems: linear single-molecule enzyme kinetics and nonlinear biochemical reaction networks

We develop the stochastic, chemical master equation as a unifying approach to the dynamics of biochemical reaction systems in a mesoscopic volume under a living environment. A living environment provides a continuous chemical energy input that sustains the reaction system in a nonequilibrium steady state with concentration fluctuations. We discuss the linear, unimolecular single-molecule enzyme kinetics, phosphorylation-dephosphorylation cycle (PdPC) with bistability, and network exhibiting oscillations. Emphasis is paid to the comparison between the stochastic dynamics and the prediction based on the traditional approach based on the Law of Mass Action. We introduce the difference between nonlinear bistability and stochastic bistability, the latter has no deterministic counterpart. For systems with nonlinear bistability, there are three different time scales: (a) individual biochemical reactions, (b) nonlinear network dynamics approaching to attractors, and (c) cellular evolution. For mesoscopic systems with size of a living cell, dynamics in (a) and (c) are stochastic while that with (b) is dominantly deterministic. Both (b) and (c) are emergent properties of a dynamic biochemical network; We suggest that the (c) is most relevant to major cellular biochemical processes such as epi-genetic regulation, apoptosis, and cancer immunoediting. The cellular evolution proceeds with transitions among the attractors of (b) in a "punctuated equilibrium" manner.     

膜反应过程及其工程问题

从膜的传递过程及反应过程的特点、膜的材质和结构、膜反应器和工程问题等方面介绍了当前膜反应技术的进展。     

Drying of a system of multiple solvents: Modeling by the reaction engineering approach

Drying is a very important industrial operation in society. In drying, solute may dissolve in an aqueous solvent, a nonaqueous solvent or a mixture of solvents. Many mathematical models have been published previously to model drying of solute in water. The reaction engineering approach (REA) is known to be an easy‐to‐use approach. It can describe well many drying cases of water removal. Currently, no simple lumped model has been attempted to describe drying of porous materials containing a mixture of solvents. In this study, for the first time, REA is constructively implemented to model drying in a mixture of one aqueous and one nonaqueous solvent. The REA is applied here to model the drying of polyvinyl alcohol/methanol/water under constant and time‐varying environmental conditions. Similar to the relative activation energy of water, that of methanol is generated through one accurate drying run. For modeling the time‐varying drying, the relative activation energies are the same as those for modeling convective drying under constant ambient conditions but combined with the equilibrium activation energies at the corresponding humidity, methanol concentration, and temperature for each drying period. The REA is accurate to model drying of a solute in nonaqueous solvent as well as in a mixture of noninteracting solvents. In the future, spatially distributed REA for nonaqueous or mixtures of both aqueous and nonaqueous solvent will be explored for fundamental understanding and for practical application. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2144–2153, 2016