煤气发生炉智能控制系统

本文深入分析了混合煤气发生炉工作原理,仔细探讨了影响煤气质量的关键因素,提出了一种全新的混合煤气发生炉控制方法——混合煤气发生炉智能控制,文中介绍了作者研制开发的智能控制系统,并给出了系统的详细框图和有关数据。     

COREX煤气压缩系统混合模型研究

在分析COREX煤气压缩系统各组成部件的工作原理基础上,根据流体力学、能量守恒和质量守恒等物理学原理,建立COREX煤气压缩系统机理模型.将COREX煤气压缩系统机理模型的参数辨识问题转化为优化问题,采用差分进化算法辨识机理模型中的未知参数.由于COREX煤气压缩系统存在较多的影响因素,机理模型预测性能不精确.基于多最小二乘支持向量机补偿机理模型的误差,建立预测COREX煤气压缩系统性能的混合模型.将混合模型应用于实际的煤气压缩系统中,结果表明与机理模型相比混合模型有更高的精度和预测性能.为控制COREX煤气压缩系统稳定运行奠定了良好的基础.     

煤气湿度计算机在线检测系统

混合煤气湿度检测与控制一直是治金系统的一大难题,涟钢混合煤气湿度计算机在线检测系统根据计算得出的数字模型,配以功能较强的研华工控机硬件,较好地实现了对混合煤气湿度计算机在线检测．94年投运以来效果较好,目前在国内尚属首例．     

混合煤气自动控制研究与应用

本文提出了一种煤气混合加压自动控制策略,解决了热值与压力耦合问题.介绍了酒钢混合煤气加压站工艺及其计算机自动控制系统的构成及功能.实际运行效果表明,系统性能稳定,运行可靠,调节效果良好.     

模糊神经网络在混合煤气解耦控制中的应用

本论文基于包钢现有高炉煤气和焦炉煤气混合调节计算机控制系统的缺陷，提出一种新的控制方法模糊神经网络智能解锅控制，从而解决了当前冶金行业中高炉、焦炉混合煤气的压力和热值不稳定的难题。     

煤气加压站无人值守和远程监控的实现

为了实现煤气系统的在线运行,对老区混合煤气加压站工艺及控制系统进行适应性改造,实现煤气加压站的无人值守和远程监控功能.     

混合煤气压力和热值的模糊解耦控制

论针对包钢现有高炉煤气和焦炉煤气混合调节计算机控制系统的缺陷，提出一种新的控制方法：模糊智能解耦控制，从而解决了高炉、焦炉混合煤气的压力和热值不稳定的难题。在简介煤气生产工艺的基础上，叙述了模糊控制原理和解耦控制方案，仿真结果表明了该方案的合理性与先进性。     

带解耦和Smith补偿器的混合煤气热值控制

采用常规仪表对混合煤气热值进行控制，难以达到满意的控制效果，因为混合煤气热值控制是一个强耦合、大滞后控制系统。对系统的耦合和大滞后问题作了详尽分析，并采用小型DCS控制器进行控制，应用前馈补偿法对系统耦合进行了静态解耦，应用Smith补偿器对热值检测滞后进行了动态补偿。控制结果表明：混合煤气热值稳定，并且提高了系统的控制精度。     

混合煤气压力和热值的模糊解耦控制

本论文基于包钢现有高炉煤气和焦炉煤气混合调节计算机控制系统的缺陷，提出一种新的控制方法：模糊智能解耦控制，从而解决了当前冶金行业中高炉、焦炉混合煤气的压力和热值不稳定的难题。     

混合煤气热值智能PID控制

针对冶金系统的煤气混合工艺过程,根据常规PID算法,结合仿人智能控制原理,作者设计了一种简单的智能PID控制器。该控制器克服了混合煤气工艺过程工况不稳定的不定因素所带来的影响,实时控制结果表明,这种控制器的采用是有效而又合乎实际的。     

专家模糊控制在煤气加压混合系统中的应用

冶金企业中大部分煤气加压站采用先混合后加压工艺,文中介绍了一种煤气先加压后混合的工艺流程,为了解决工艺流程控制中热值和压力波动大的缺陷,提出一种基于PLC的模糊和专家控制器,并详细介绍了其实现方法。经过实际应用取得了很好的效果,热值、压力控制偏差均小于4%。     

Y沸石改善SnO2气体传感器性能的研究

为了改善气体传感器的敏感性能,分别采用SnO2外涂Y沸石的涂覆法和Y沸石与SnO2混合法,用Y沸石对SnO2气体传感器进行改性.用X-射线衍射(XRD)、电子扫描显微镜(SEM)对混合法制备的Y沸石/SnO2复合材料的结构和表面进行了表征与分析.将这两类敏感元件进行了VOC气体的气敏测试.结果表明,与纯SnO2相比,Y沸石与SnO2直接混合的复合材料提高了对丙酮的响应值,而对其他气体响应值基本不变;涂覆法制备的气敏元件不仅提高对丙酮的响应值,而且减小了对乙醇的响应值,对乙醇起到一定抑制作用.初步分析了Y沸石对SnO2气敏特性改善的机理.     

Optically monitored segmented flow for controlled ultra-fast mixing and nanoparticle precipitation

Nanoparticles of drugs or colloidal carrier systems are capable of providing substantial advantages for drug bioavailability, but manufacturing nanoparticulate drugs or drug carriers remains a challenge because traditional mechanical or chemical batch mode processes might lack precise control of nanoparticle sizes. Microfluidic approaches are believed to give advantages but often do not provide chemically inert environments and lack controllable operation. Here, segmented flow devices with symmetrical design for centered organic phase injection and for nanoparticle precipitation in transparent and chemically inert glass microchannels are presented. Femtosecond laser fabrication was used to structure borosilicate glass wafers with hydrophilic microchannels of nearly circular cross section. They allow for ultra-fast mixing of solvents with aqueous fluids and subsequent precipitation of poorly water soluble drug nanoparticles or colloidal carrier particles. The best results for mixing and controlled precipitation were obtained with flow focusing and gas segmentation occurring at the same channel intersection point. In such systems, early interdiffusion of the solvent and aqueous solution before ultra-fast convective mixing in the plug is suppressed. A novel optical analysis technique revealed that the speed of mixing can be well controlled by simply adjusting the volume flow rate of the gas phase where changes in the liquid flow rate have practically no influence. In a controlled and stable Taylor flow, smallest plug volumes of 3.8 nl can be generated, which allows complete mixing in 9 ms. The production of lipid nanoparticles down to a diameter of 74 nm could already be demonstrated.     

基于混合煤气加压站热值及压力控制的研究

混合煤气在钢铁企业中用途非常广泛,一般是两种甚至是三种热值不同的煤气经混合、加压之后送至煤气用户比如加热炉等,而加热炉对煤气的压力、热值均有较高的要求,因此如何得到压力、热值均比较稳定的混合煤气就显得尤为重要。通过对煤气混合的原理分析,详细介绍了混合加压的流程及控制方案,并对某钢厂煤气混合站的实际数据进行分析,实践证明,分步控制方案能较好地解决热值及压力控制。     

Simulation and characterization of microreactors for aerosol generation

This paper shows the application of T-shaped micromixers for the generation of aerosols with nanoscale droplets by the mixing of a hot vapor–gas mixture with a cold gas. The fast mixing within a T-shaped micromixer leads to a high supersaturation of the vapor and therefore to an instantaneous, homogeneous nucleation and particle growth. Different mixer geometries, mixing ratios, and gas temperatures have been investigated by numerical simulation to yield optimum mixing results over a wide range of operational parameters. Optimized microreactor geometries were designed and fabricated in silicon with Pyrex glass lids. Special attention was paid to thermal insulation and particle deposition at the channel walls. This concerns not only the mixing chip, but also the design of the fluidic mount with only few bends and corners. Initial experimental results for particle deposition and aerosol generation are presented. High temporal temperature gradients up to 10⁶ K/s lead to a rapid condensation and forming of nanosized particles with a mean diameter of 20–50 nm and a narrow size distribution.     

Statistical properties of controlled fluid flows with applications to control of mixing

In this paper, we study statistical properties of fluid flows that are actively controlled. Statistical properties such as Lagrangian and Eulerian time-averages are important flow quantities in fluid flows, particularly during mixing processes. Due to the assumption of incompressibility, the transformations in the state space can be described by a sequence of measure preserving transformations on a measure space. The classical Birkhoff's pointwise ergodic theorem does not necessarily apply in the context of sequences of transformations. We call B-regular a sequence for which this theorem holds. Motivated by mixing control concepts, we define three notions of asymptotic equivalence for sequences of transformations. We show an example in which Birkhoff's pointwise ergodic theorem does not hold even when a ‘strong’ asymptotic equivalence to a B-regular sequence is assumed. Under a ‘very strong’ asymptotic equivalence condition, we prove B-regularity. In the context of optimize-then-stabilize strategy for mixing control, we also prove that very strong asymptotic equivalence to a mixing sequence implies mixing. The mean ergodic theorem and the Poincare’ recurrence theorem are also proven for sequences of transformations under suitable asymptotic equivalence assumptions.     

CO余热锅炉瓦斯燃烧器改造及仿真研究

中石化某分公司催化裂化装置CO余热锅炉运行过程中,瓦斯燃烧器燃气空气混合不充分,火焰温度分布不均匀,燃烧效果差.为解决此问题,分析了瓦斯燃烧器的工作特点及结构形式,对燃烧器的配风方式、气流混合原理及稳燃机理进行了研究,并对燃气系统进行了核算,提出了燃烧器改造方案,最后运用计算流体力学(CFD)软件FLUENT,对改造前后的燃烧器内的燃烧情况进行了模拟.仿真结果表明,改造后的燃烧器火焰温度分布均匀,燃烧完全.燃烧器改造方案是合理可行的.     

Characterisation and control of bubbling behaviour in gas–solid fluidised beds

Bubbling fluidised beds are often exploited for the good mixing of phases they promote, which is required in many chemical processes. However, the bubbles cause heterogeneity in the fluidised system, and their dynamics must be understood for good process control. In this paper, the dynamic behaviour of the bubbles in a planar gas–solid fluidised bed is described analytically and experimentally validated. The bed resembles a temporary buffer of gas for which the bubble residence time in the bed is important. Subsequently, a closed-loop controller was developed using visual feedback to regulate the process.     

面向NOx脱除率优化的烟气脱硝CFD仿真研究

烟气脱硝的技术关键是还原剂与烟气混合要尽可能均匀,混合气体通过催化剂层时速度分布要尽可能均匀.以600 MW超临界燃煤火力电站烟气脱硝(DeNOx)系统为对象,对还原剂氨和烟气的混合过程进行了计算流体力学仿真,研究了关键导流板对喷氨格栅前烟气速度分布和催化剂入口处烟气速度分布的影响,并确定其尺寸及安装位置.为提高催化剂入口氨浓度分布的均匀性,根据喷氨格栅处烟道截面速度分布特点,通过仿真寻优,得到了非均匀喷氨流量设定值.