甲烷化工艺的热管理与反应器设计优化研究

甲烷化工艺在现代工业中具有重要的应用价值,广泛用于合成天然气、净化工业尾气以及氢气生产等领域,随着能源需求的不断增长和环境保护要求的提高,甲烷化工艺的重要性愈加凸显。甲烷化反应为强放热反应,易导致反应器内部温度不均匀,影响催化剂的活性和反应效率,因此,如何有效管理甲烷化工艺的热量和优化反应器设计,成为当前研究的重点。本文通过系统探讨甲烷化工艺中的热管理策略与反应器设计优化方法,深入分析甲烷化反应的热力学特性和催化剂活性,提出有效的热管理策略,确保反应过程的稳定性和高效性。同时,优化反应器的设计,提高催化剂的利用率和反应效率。

电子束辐照水处理反应器的CFD模拟与优化

以处理量较大的射流式电子束辐照水处理反应器为例,运用计算流体力学方法,以反应器出口水流流速分布均匀为目标,对反应器内部水流的水动力特性及反应器构型对出口水流流速分布均匀性的影响进行了研究,并据此优化反应器的构型.研究结果表明,影响反应器水动力特性的关键构型参数为反应器进口管径、反应器水平收缩段长度和反应器弯曲段构型.反应器进口管道直径越大、水平收缩段长度越大,则反应器出口水流流速分布越均匀.最终确定最优反应器的构型参数为:进口管径0.2m,水平收缩段长度0.45m,反应器弯曲段构型贴合水流运动方向.计算结果表明,最优反应器的水动力条件得到极大改善,反应器出口水流流速分布非常均匀.物理模型试验验证了最优反应器出口水流流速分布的均匀性.

基于免疫机制的多目标蚁群算法用于间歇反应器的约束动态多目标优化

含路径和终端约束的动态多目标优化是过程系统工程的一个重要研究方向,难度较高。传统蚁群算法仅适于离散问题,今采用混合正态分布描述信息素分布,并设计相应的解构造操作,使之拓宽至连续优化问题。通过对目标函数和约束矩阵的非劣排序,确定解的等级,用以克服传统约束处理方法的局限性。借鉴了免疫系统的浓度概念,将其与解的等级结合,共同确定解的适应度,有助于保持种群的多样性。在更新信息素时将利用外部优解库和种群信息,可加快收敛速度。基于拥挤度距离更新外部优解库可更均匀地逼近Pareto最优解集。由此构建了一种基于免疫机制的多目标蚁群算法(Immune Mechanism based Multi-Objective Ant Colony Algorithm,IM-MOACA),并用于间歇反应器的动态多目标优化问题,效果良好,显示出较强的全局优化性能,能以较快的速度逼近真实的Pareto最优前沿,可为用户进行合理的决策分析提供有效的支持。

计算流体力学在生物反应器模拟中的应用

该文综述了计算流体力学在生物反应器优化模拟中的应用研究进展,总结了计算流体力学模拟方法、参数选择及近年来在生物反应器优化方面的应用,并对其在生物反应器优化研究方向提出了展望。

热化学反应器放热过程模拟及参数影响规律

热化学储热因其具有储热密度高、存储过程几乎无热量损失等优点在推动可再生能源的利用、助力实现“双碳”目标中具有重要作用,其中热化学反应器的设计及性能优化是重要环节。本文对以硅胶球为储热材料的热化学反应器进行了放热实验,并建立了二维仿真模型。通过调整模型参数中硅胶球最大吸水量、亲和系数、非均质参数及指前因子和活化能等参数使数值模拟和实验的反应器出口温度结果具有良好的一致性。参数中对空气出口温度影响较大的有亲和系数、非均质参数及硅胶球最大吸水量,比热容的影响最小,指前因子对空气出口温度的影响大于活化能。其中非均质参数由1.2增大至2.8时,空气最高出口温度由140℃降低至70℃。增大硅胶球的比热容在降低反应器最高出口温度的同时,还有助于延长到达最高出口温度的时间。该研究结果结合小型反应器实验数据可以对大规模储热装置多次充放热循环后的性能进行更加准确地预测,进而优化反应器及系统设计。

赢创研制的新型反应器引发了一场小小的革命

作为欧盟“地平线2020”研究计划的一部分,赢创和来自5个国家的9个项目合作伙伴,成功开发了一种新颖的反应器,用于OXO催化反应,其能效提高了70%。ROMEO(采用膜过程强化的反应器优化)项目于2015年启动,旨在开发一种全新反应器。这种反应器可用于均相催化反应——烯烃与合成气氢甲酰化反应制备醛。

三相介质阻挡放电产生过氧化氢的条件优化

过氧化氢、臭氧和羟基自由基等是介质阻挡放电过程中产生的主要活性粒子,其中过氧化氢对水中污染物质的去除起重要作用。为考察多高压电极介质阻挡放电反应器对放电过程中过氧化氢浓度的影响,采用线筒式三相介质阻挡放电反应器,用正交实验研究了高压电极材料、数目以及高低压电极间距的改变对过氧化氢浓度的影响。结果表明:影响过氧化氢浓度的因素显著性顺序为电极种类、高低压电极间距、电极数目;当3根直径为3mm的不锈钢丝作高压电极且高低压电极间距为13 mm时,系统产生的过氧化氢浓度最高;在最佳的系统条件下,提高空气流量、峰值电压和放电频率,降低电导率都有利于过氧化氢的生成。系统产生的最高过氧化氢浓度为64.2μmol/L。

煤化学链转化技术研究进展

化学链技术为化石能源的清洁高效利用提供了新思路。本文在综述煤化学链燃烧和气化转化工艺现状及特点的基础上,对煤化学链转化的载氧体以及煤-载氧体反应和化学链反应器强化等进行了评价及展望。指出煤化学链转化的研究重点为以下3方面:①载氧体-煤-煤灰-气化剂等反应体系中氧传递过程及反应机理;②载氧体应围绕多活性组分载氧体、耦合催化-载氧-捕C/S多功能复合载氧体和具有特定储氧功能和高稳定性结构载氧体等3方面进行研究;③针对载氧体和煤反应慢的瓶颈,应揭示反应器优化和操作强化的理论基础。

新型厌氧氨氧化工艺在高含氮废水处理中的应用

厌氧氨氧化工艺是"未来概念污水厂"的重要组成部分,它具有无需曝氧、污泥产量低、工艺流程短、运行费用低、低碳环保等诸多优势,但同时也面临着启动周期长、运行条件苛刻、总氮去除率低等一系列问题。因此,本文从反应器优化、复合菌群优化和总氮去除优化三个方面介绍新型厌氧氨氧化工艺在高含氮废水处理中的应用,以期完善拓展厌氧氨氧化工艺的研究领域,并为厌氧氨氧化工艺的发展提供新思路。

废水高效水解酸化试验研究

提出了一种高效水解酸化废水处理技术。通过科学的反应器结构设计,实现水解酸化系统良好的水力条件和生化条件,从而保证高传质速率下的高净化效能,进而实现系统有机污染物去除的高效性。

故障诊断中的函数连接网络

函数连接网络通过产生一组线性独立的函数 ,将原输入模式进行一次非线性扩展后作为单层感知器的输入 ,从而克服了学习速度慢 ,易陷于局部极小点的问题 把这种网络用于故障模式分类并和BP网进行比较 。

生物净化强化技术治理VOCs的研究进展

综述了利用表面活性剂、真菌微生物和优化生物反应器的生物净化强化技术,该技术在治理疏水性、难降解VOCs中具有独特优势,重点阐述了生物净化强化技术在治理大气VOCs中的研究进展,指出表面活性剂因其具有良好的增溶性、低能耗、无二次污染等特性,在强化生物技术方面成为目前研究的重点。提出了生物净化强化技术面临的主要问题及未来的研究方向,将该技术逐渐推向工业化,并与其他治理技术根据实际情况进行联合使用,以产生最大的经济、环境效益。

Simulation and Design Optimization of Ammonia Synthesis Converter

One-dimensional pseudo-homogeneous model of an axial flow converter and one-dimensional heteroge-neous model of a horizontal converter have been presented, which describe the distribution of gaseous composition,temperature and pressure along the height in the two converters, respectively. Design optimization methods of the two converters have been proposed, by which the minimum catalyst volume can be obtained to satisfy the productive capacity of 1000 tons per day, when the operating pressure is 15.0, 10.0 and 7.5 MPa, respectively.

Modeling-based optimization of a fixed-bed industrial reactor for oxidative dehydrogenation of propane

An industrial scale propylene production via oxidative dehydrogenation of propane （ODHP） in multi-tubular re- actors was modeled. Multi-tubular fixed-bed reactor used for ODHP process, employing 10000 of small diameter tubes immersed in a shell through a proper coolant flows. Herein, a theory-based pseudo-homogeneous model to describe the operation of a fixed bed reactor for the ODHP to correspondence olefln over V2O5/γ-Al203 catalyst was presented. Steady state one dimensional model has been developed to identify the operation parameters and to describe the propane and oxygen conversions, gas process and coolant temperatures, as well as other pa- rameters affecting the reactor performance such as pressure. Furthermore, the applied model showed that a double-bed multitubular reactor with intermediate air injection scheme was superior to a single-bed design due to the increasing of propylene selectivity while operating under lower oxygen partial pressures resulting in propane conversion of about 37.3%. The optimized length of the reactor needed to reach 100% conversion of the oxygen was theoretically determined. For the single-bed reactor the optimized length of 11.96 m including 0.5 m of inert section at the entrance region and for the double-bed reactor design the optimized lengths of 5.72 m for the first and 7.32 m for the second reactor were calculated. Ultimately, the use of a distributed oxygen feed with limited number of injection points indicated a significant improvement on the reactor performance in terms of propane conversion and propylene selectivity. Besides, this concept could overcome the reactor run- away temperature problem and enabled operations at the wider range of conditions to obtain enhanced propyl- ene production in an industrial scale reactor.

Optimizing Reactors Selection and Sequencing: Minimum Cost versus Minimum Volume

The present investigation targets minimum cost of reactors in series for the case of one single chemical reaction, considering plug flow and stirred tank reactor(s) in the sequence of flow reactors. Using Guthrie's cost correlations three typical cases were considered based on the profile of the reaction rate reciprocal versus conversion. Significant differences were found compared to the classical approach targeting minimum total reactor volume.

A two-level measurement-based dynamic optimization strategy for a bioreactor in penicillin fermentation process

One measurement-based dynamic optimization scheme can achieve optimality under uncertainties by tracking the necessary condition of optimality(NCO-tracking), with a basic assumption that the solution model remains invariant in the presence of all kinds of uncertainties. This assumption is not satisfied in some cases and the standard NCO-tracking scheme is infeasible. In this paper, a novel two-level NCO-tracking scheme is proposed to deal with this problem. A heuristic criterion is given for triggering outer level compensation procedure to update the solution model once any change is detected via online measurement and estimation. The standard NCO-tracking process is carried out at the inner level based on the updated solution model. The proposed approach is illustrated via a bioreactor in penicillin fermentation process.

Optimal design for split-and-recombine-type flow distributors of microreactors based on blockage detection

In order to increase the productivity of microreactors, the parallelization of the microreactors is required. The performances of flow distributors can affect the product yield and fault detection ability when blockage happens.In this research, an optimal design method to calculate the channel diameters and to determine the flow sensor location is derived based on mass balance and pressure balance models of split-and-recombine-type flow distributors(SRFDs). The model accuracy is verified by experiment data. The proposed method is applied to optimal design of SRFDs under constant flow rate operation conditions. The maximum angle difference between normal and blockage conditions at one sensor to those at the other sensors is set to be the objective function and the uniformity of flow distribution in microreactors under normal condition is also required. The diameters of each pipe in SRFDs are selected as the design variables. Simulated annealing algorithm is used to solve the optimization problem. The effectiveness of the optimal design results is demonstrated by fluid dynamics simulations. The results show that using the optimal channel diameters of SRFDs, the pressure drop in SRFD section is lower than that of the microreactor section. Meanwhile, in the case studies, only a few sensors that are located inside the SRFDs can easily detect the blockage abnormal condition in the parallelized microreactor system.

Hydrodynamics research of wastewater treatment bioreactors

To optimize the design and improve the performance of wastewater treatment bioreactors,the review concerning the hydrodynamics explored by theoretical equations,process experiments,modeling of the hydrodynamics and flow field measurement is presented. Results of different kinds of experiments show that the hydrodynamic characteristics can affect sludge characteristics,mass transfer and reactor performance significantly. Along with the development of theoretical equations,turbulence models including large eddy simulation models and Reynolds-averaged Navier-Stokes (RANS) models are widely used at present. Standard and modified k-ε models are the most widely used eddy viscosity turbulence models for simulating flows in bioreactors. Numerical simulation of hydrodynamics is proved to be efficient for optimizing design and operation. The development of measurement techniques with high accuracy and low intrusion enables the flow filed in the bioreactors to be transparent. Integration of both numerical simulation and experimental measurement can describe the hydrodynamics very well.

Modeling of Solar Thermochemical Receiver

This work provides information for an optimal design of a thermochemical storage system, through a proposed mathematical model that predicts the behavior of a solar fluidized bed receiver finding the temperature and concentration profiles in transient state. The mathematical model is developed for a fluidized bed solar reactor, taking into account dynamics conditions of heating and reaction. The heating was simulated for radiated flux with a normal distribution over lateral walls and with distributed flow conditions of the focal stain. The contraction and expansion effects of the bed were involved with a two dimensional distribution. The mathematical model of a solar fluidized bed reactor involves a reversible chemistry reaction of thermal dissociation of the zinc sulfate （ZnSO4）, also the mathematical model is accomplished by a sensitivity study with regard to the gas inlet temperature and radiation flux.

Novel photocatalytic reactor for degradation of DDT in water and its optimization model

A novel photocatalytic reactor was developed to remove （1,1-bis（4-chlorophenyl）-2,2,2-trichloroethane） （DDT） from water. In the reactor, a cenosphere was used to support TiO2 film made by means of sol-gel. Because the cenospheres were coated with TiO2, their specific gravity was slightly increased from the original 0.6-0.8 to 0.8-0.9, so that they were able to be suspended in water. With the mixed operation of a bubbler, the water in the reactor was in a well-fluidized state. The bottom of the reactor is a sand filter bed, which can be used to prevent the photocatalyst from being lost. A mathematical model of the reactor has been developed in the two primary influential factors： ultraviolet （UV） light intensity and photocatalyst concentration. With such a model, the reactor can be designed more reasonably.