阴极冷却固定床电合成乙醛酸的连续过程模拟

联用反应动力学、电荷衡算和物料衡算建立阴极冷却固定床草酸电合成乙醛酸反应器模型方程.针对反应器连续化操作过程,用正交配置法数值求解该模型方程.结果表明,在连续化操作的反应初期,反应液中的乙醛酸能够较快地达到预定浓度,但继续增加反应器的长度,反应的效果不明显.该模型还模拟了分段温控和部分回流对反应的影响.结果表明,分段温控和部分回流均可较好地提高乙醛酸在阴极液中的浓度.计算结果与试验操作基本相符.该结果对阴极冷却固定床草酸电合成乙醛酸的连续化操作工艺和反应器的优化具有重要的参考意义.     

Method of composition heterogeneity reduction in copolymer of butadiene with isoprene in ionic coordination polymerization with supported titanium catalysts

Compositional heterogeneity of copolymers of butadiene with isoprene in copolymerization with supported titanium catalyst was investigated. The causes of compositional heterogeneity were found based on solution of an inverse problem of formation of the molecular weight distribution. It was shown that the pre-hydrodynamic effects in a turbulent reactor at the stage of the reaction mixture formation allowed the synthesis of more uniform composition of the copolymer.     

Shrinking-bed model for percolation process applied to dilute-acid pretreatment/hydrolysis of cellulosic biomass

For many lignocellulosic substrates, hemicellulose is biphasic upon dilute-acid hydrolysis, which led to a modified percolation process employing simulated two-stage reverse-flow. This process has been proven to attain substantially higher sugar yields and concentrations over the conventional single-stage percolation process. The dilute-acid pretreatment of biomass solubilizes the hemicellulose fraction in the solid biomass, leaving less solid biomass in the reactor and reducing the bed. Therefore, a bed-shrinking mathematic kinetic model was developed to describe the two-stage reverse-flow reactor operated for hydrolyzing biphasic substrates, including hemicellulose, in corn cob/stover mixture (CCSM). The simulation indicates that the shrinking-bed operation increases the sugar yield by about 5%, compared to the nonshrinking bed operation in which 1 reactor volume of liquid passes through the reactor (i.e.,t = 1.0). A simulated optimal run further reveals that the fast portion of hemicellulose is almost completely hydrolyzed in the first stage, and the slow portion of hemicellulose is hydrolyzed in the second stage. Under optimal conditions, the bed shrank 27% (a near-maximum value), and a sugar yield over 95% was attained.     

Investigation of coupling dehydrogenation and hydrogenation reactions in a fixed bed catalytic reactor with well-mixed catalyst pattern

The enhancement of ethylbenzene conversion by further displacement of the thermodynamic equilibrium via the influence of the dual-functionality of a well-mixed catalyst pattern has been investigated. A rigorous steady state mathematical model based on the dusty gas model is implemented for the simulation. The simulation results reveal that the introduction of the concept of the reaction coupling has significant effect on the displacement of the thermodynamic equilibrium and considerable enhancement of simultaneous production of styrene and cyclohexane. Almost 100% conversion of the ethylbenzene and benzene is achieved through the application of this approach. It is also found that considerable decrease in the reactor length is achieved by employing a reactor catalyst bed with different bed compositions. Effective operating regions with optimal conditions are observed. An effective reactor length criterion is used to evaluate the performance of the reactor under these optimal conditions. The effective reactor length is found to be sensitive and favored by high feed temperature and pressure. The sensitivity analysis shows that the key parameters of feed temperature, pressure, and the bed composition play an important role on the reactor performance. The results also show that almost 100% conversion of ethylbenzene and benzene at low temperature and shorter reactor length can be achieved by maintaining the reactor beds at different temperatures. This temperature switching policy may result in appreciable energy saving. Moreover, operating the reactor at low temperature protect the catalyst from the excessive temperatures which have destructive effects on the catalysts and the mechanical stability of the reactors. Also, the low temperature operation has significant contribution to the reduction of the operating cost.     

Optimal temperature conditions of carbonaceous feedstock pyrolysis

A problem of optimal control of the temperature conditions of carbonaceous feedstock pyrolysis in a plug-flow reactor was formulated, and it was shown that the optimal temperature profile depends significantly on the ratio between the activation energies of the desired and side reactions and also on the type of the main pyrolysis reactions (consecutive, parallel, or consecutive-parallel).     

Optimal control determination of MMA polymerization in non-isothermal batch reactor using bifunctional initiator

In this work, we determine the optimal control for free-radical methyl methacrylate polymerization using a bifunctional initiator in a non-isothermal batch reactor. A detailed unsteady-state model of the process is employed. Four different optimal control objectives are realized, each of which optimizes a given variable simultaneously with the specification of another. The first two objectives involve the maximization of monomer conversion in a specified operation time, and the minimization of operation time for a specified, final monomer conversion. The last two objectives involve the maximization of monomer conversion for specified, final number and weight average polymer molecular weights. The temperature of heat-exchange fluid inside reactor jacket is considered as a control function of an independent variable. To meet the specification of an optimization variable other than time, the differential model of batch process is derived in the range of specified variable. Equations are provided for Jacobian evaluations to help in the accurate solution of process model. A genetic algorithms-based optimal control method is applied to realize the four optimal control objectives. The results show that optimal control can significantly enhance the performance of the batch polymerization process.     

吸收增强式甲烷水蒸气重整制氢实验研究

利用固定床反应器对吸收增强式甲烷水蒸气重整制氢反应进行了考察，研究了温度、甲烷流量、颗粒粒径和吸收剂种类等参数对反应过程的影响。结果表明，吸收增强式制氢反应过程最佳反应温度受热力学和动力学两方面因素影响；常压下以CaO为吸收剂时，最佳反应温度为600℃~700℃；CH4流量的选取要根据反应器内吸收剂的量与吸收增强段持续时间综合比较而定； 颗粒粒径大于90 μm，分析纯CaO和新型钙基CO2吸收剂CaO/Ca12Al14O33 均能达到较好的吸收增强效果。     

草酸电解合成乙醛酸连续化工艺研究

针对传统草酸电解生产乙醛酸工艺只能间歇循环的缺陷,本文提出模拟连续化实验方案,并分别设计阴极冷却反应器和阴极冷却固定床反应器,探讨连续化实验的可行性.另外还考察了草酸饱和度和温度工艺参数对反应的影响.实验表明,保持草酸过饱和和利用变温操作可在反应停留时间(30m in)内于连续化反应过程中得到分别含有3.76%和3.66%乙醛酸的反应液,因此阴极冷却固定床反应器可望实现草酸电解还原乙醛酸的连续化生产.     

The pyrolysis of octafluorocyclobutane—Revisited

A high-pressure, high-temperature reactor unit was developed to test batch-wise inter-conversions of hydrocarbons. A major ambiguity characterizes this reactor, as it does all similar units that have been described, determination of the time-temperature profile for the reacting mixture. Here we report on a solution to this problem—use of a “chemical thermometer,” based on the kinetics of dissociation of C₄F₈. We propose a revised set of rate constants that permit calibration of the reactor operation. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet 30: 171–177, 1998.     

Removal of Phenol Dyes Using a Photocatalytic Reactor with SnO2/Fe3O4 Nanoparticles

In this study, we present kinetics of phenol dyes removal by SnO₂/Fe₃O₄ nanoparticles in a photocatalytic reactor for optimization of this process. The effect of different concentrations of SnO₂ 5, 10, 15, 20% w/w on the photocatalytic reactor during removal of phenol red was investigated. The SnO₂/Fe₃O₄ nanoparticles were synthesized by core–shell method. The results of XRD and TEM showed the successful synthesis of these nanoparticles. Several other methods were applied to synthesis of these nanoparticles but none of them succeeded. This process composed of two-stage. The first stage was absorption by iron oxide nanoparticles and second stage was photocatalytic by tin oxide nanoparticles that followed pseudo-second-order kinetic and first-order kinetic, respectively. Optimization of this process was done corresponding to the parameters affecting the process with design expert software. In order to determine the optimal values of each of the parameters and the optimal conditions of the process, parameters were introduced to response surface methodology.     

Robust stabilization of a chemical reactor

Robust static output feedback control was applied to a continuous stirred tank reactor with parametric uncertainty and multiple steady states in which exothermic reaction takes place. The problem of robust controller design was converted to a solution of linear matrix inequalities and a computationally simple non-iterative algorithm is presented. The possibility of using robust static output feedback for stabilization of reactors with uncertainty and comparison of robust P and PI controllers with an optimal controller is demonstrated by simulation results.     

低浓度甲烷流向变换催化燃烧的研究

甲烷在煤矿工业中被称作为瓦斯,在富含甲烷的矿井中甲烷的体积分数为0．1％～1．0％,在煤矿开采过程中甲烷的体积分数达到5％～15％就会造成瓦斯爆炸。如果能够将煤矿中的甲烷抽取出来利用,不但可以减少矿难事故的发生,而且能够提供更多可利用的清洁能源。因此,如何将此低品位的资源转化为可利用的能源,具有重要的研究价值。另外,甲烷的温室效应是CO2的21倍。因此,将伴随某些工业生产以及石油开采过程产生的低浓度甲烷直接排放到大气中,势必会造成严重后果。     

聚氯乙烯的热解特性和热解动力学研究

随着聚氯乙烯的大量使用,聚氯乙烯在总固体废弃物中占的比例愈来愈高,成为固体废弃物中的重要组分.如何科学、合理、有效地妥善解决聚氯乙烯问题是当前一项急待解决的重要课题.……     

Closed-loop recirculating manifold for matrix isolation in flow injection flame atomic absorption spectrometry. Analysis of silver electrolysis solutions

Two flow injection procedures have been investigated for the determination of some elements in silver electrolysis solutions, for which the problem of the formation of silver acetylide needs to be addressed. A single line manifold was found to give acceptable results for limited time periods, but for prolonged operation it was necessary to remove the silver. This was achieved with a recirculating reactor in which the silver was precipitated as the chloride and retained on a filter of nylon fibers. Good recoveries of copper, iron, nickel and zinc from solutions containing up to 100 g/l. silver were obtained with over 95% of the silver retained on the filter. The filter was regenerated rapidly by flushing with ammonia solution.     

C302铜基甲醇合成催化剂颗粒设计Ⅱ. 颗粒结构对Lurgi型合成反应器性能的影响

基于本文（I）报的研究结果，以固定床反应器二维非均相数学模型为基础，模拟考察了C302铜基甲醇合成催化剂颗粒设计对Lurgi型合成反应器性能的影响。结果表明，由于颗粒结构设计改变了粒内反应－扩散耦合行为的相互匹配关系，使得催化剂的宏观反应活性发生变化，进而对反应器的操作性能产生显著的影响（包括反应器生产能力、温度和浓度分布特性、床层压力降和热点温度等），为提高反应器的生产能力和改善反应器的操作性能，进行催化剂颗粒的适宜结构设计是非常必要和有价值的。     

Simulation and model design of pipe-shell reactor for the direct synthesis of dimethyl ether from syngas

The simulation was made based on the model of pipe-shell reactor that was established by the model of global kinetics of synthesis of dimethyl ether from syngas over a bifunctional catalyst. The results of simulation showed that the selectivity for dimethyl ether （DME） and the conversion of CO were higher but the hot spot was kept below the temperature limit of the pipe-shell reactor. The suitable diameter of the pipe was φ38×2 mm, and the length of the pipe was 5.8 m. The optimal process conditions of the reactor were that the pressure was 5 MPa, the temperature of the cooling water was 240 ℃, and the temperature of the raw gas at inlet of the reactor was 220 ℃. The production of this reactor was 102800 t/y （ton per year） under these conditions.     

外循环式耐硫甲烷化反应器分析

建立了耐硫甲烷化循环式反应器的拟均相一维模型，考察了床层直径，循环比，入口气体温度及压力和温度范围对反应器操作的影响，结果表明：循环比和温度操作范围是反应器操作的决定因素，对日产５万标准立方煤气的反应器进行了优化设计分析。     

CO偶联-再生反应合成草酸二乙酯过程的模拟(英文)

采用序贯模块法ＡＳＰＥＮ、ＰＲＯ／Ⅱ及二维拟均相气固反应器和鼓泡塔气液反应器模型的程序对ＣＯ气相偶联合成草酸二乙酯两步反应循环系统进行模拟和调优,同时考察了各种操作条件对整个系统的影响,计算出适宜的操作范围。模拟结果与模实验数据进行了显著性检验,其置信度为 ９５％。     

Characteristics of bio-diatomite dynamic membrane process for municipal wastewater treatment

The characteristics of bio-diatomite dynamic membrane (BDDM) process in municipal wastewater treatment were investigated with a laboratory-scale continuous-flow device. Experimental results indicate that the BDDM reactor was highly effective in removal of COD, NH₄-N and TN, and exhibited the advantages of good retention capacity for suspended solids (SS), short precoating time, high filtration flux, and easy backwash. In the precoating stage, a retention time of 25 min could reduce the effluent SS to non-detectable level. The filtration resistance of BDDM was composed of thickness-increase resistance and compaction resistance. At a low flux, microbial adhesion occurred on the interface between the BDDM and the stainless steel support mesh, which negatively impacted the system operation and backwash. However, microbial adhesion could be effectively minimized by increasing the filtration flux.