Fuzzy logic control of a reverse flow reactor for catalytic oxidation of ventilation air methane

Fuzzy logic controllers of type-1 and type-2 were implemented to deal with the high nonlinearities and uncertainties in operation of a reverse flow reactor (RFR) for catalytic oxidation of ventilation air methane (VAM). The results indicated that the fuzzy logic controller is distinctly superior to the traditional logic-based controller and works well under the conditions with high nonlinearities and uncertainties. Owing to the robustness of RFR and particular control aim of regulating bed temperature within a relatively broad range, a fuzzy logic controller of type-1 is sufficient to cope with the uncertainty brought by the extensive variation of VAM concentration.     

MATLAB GUI在表征煤层气解吸行为过程的应用

建立煤层气解吸过程的数学模型,利用MATLAB软件中图形用户界面(Graphical User Interface,GUI)功能,完成煤层气解吸过程的界面设计,编写各控件回调函数的程序代码,实现各控件相应的功能。软件界面简单、操作方便、内容丰富、交互性好,可以快速的绘制煤层气解吸过程系列曲线,直观的表征煤层气解吸过程的特征。具有在任何位置取点的功能,及可获取煤层气解吸过程三个关键压力点(转折压力、启动压力和敏感压力),并对曲线进行划分,从而指导实际生产。     

催化元件配对工艺及瓦斯检测方法优化

通过研究热催化瓦斯传感器催化传感元件的动态配对工艺,增强了传感元件和补偿元件的一致性,抑制了零点漂移。采用新的检测方法,改善了传感器的工作状态,提高了传感器的灵敏度和稳定性。传感器灵敏度自动调校的研究有利于瓦斯监测系统自动化与可靠性的提高。     

抗毒载体催化元件的实验研究

载体催化元件在含有硫化氢的环境中长期工作 ,会发生催化剂中毒 ,这严重影响着元件在这些环境中的应用。文章分析了载体催化元件中毒失活的本质 ,通过实验研究 ,探讨了铂钯催化剂系统抗硫化氢中毒的一般策略。     

均匀沉淀法制备高性能催化燃烧式甲烷传感器

为了提高催化燃烧式甲烷传感器的性能,以介孔SBA- 15作为载体,采用均匀沉淀法制备具有不同Pd担载量的敏感材料.通过XRD和氮气吸脱附表征材料的组成及结构,并以该材料构筑敏感元件,研究其气敏特性.与传统浸渍法合成的Pd/γ-Al2 O3相比,Pd/SBA-15对于甲烷具有更加出色的敏感特性,这主要源于其高比表面积、小...     

Novel photocatalyst-based colourimetric indicator for oxygen: Use of a platinum catalyst for controlling response times

The preparation and characterisation of a novel, UV-activated, solvent-based, colourimetric indicator for oxygen is described, comprising a redox dye (methylene blue, MB), semiconductor photocatalyst (Pt-TiO₂), and a sacrificial electron donor (SED = glycerol), all dispersed/dissolved in a polymer medium (sulfonated polystyrene, SPS). Upon exposure to UVA light, the Pt-TiO₂/MB/glycerol/SPS oxygen indicator is readily photobleached as the MB is converted into its oxygen-sensitive, leuco form, LMB. In contrast to its non-platinised TiO₂ counterpart (TiO₂/MB/glycerol/SPS oxygen indicator), the recovery of the original colour is faster (ca. 1.5 days cf. 5 days at 21 °C). This is due to the catalytic action of the 0.38 wt% platinum loaded onto the semiconductor photocatalyst, TiO₂, on the oxidation of the photogenerated LMB by ambient O₂. Furthermore, by increasing the level of platinum loading, recovery times can be decreased further; e.g. a Pt-TiO₂/MB/glycerol/SPS oxygen indicator with platinum level of 1.52 wt% recovers fully within 12 h. A study of the kinetics of recovery as a function of film thickness revealed the recovery step is not controlled by the diffusion of O₂ through the film, but instead dependent upon the slow rate of oxidation of LMB to MB by O₂ in the low dielectric polymer encapsulation medium. Other work showed this recovery is only moderately dependant upon temperatures above −10 °C and very sensitive to relative humidity above 30% RH. Potential uses of this UV light activated indicator are discussed briefly.     

计算机辅助催化剂组分分子设计的思想和实现

从催化科学和人工智能相结合的角度。阐述了在计算机辅助催化剂组分分子设计中面向催化反应机理和面向物种活性模型的分子设计过程，以一系列常见的催化反应活性模型作为用户交互内容，建立了初步的催化剂分子设计专家系统ＥＳＭＤＣ，说明了其工作原理和设计工程，并介绍了该系统在甲烷氧化偶联金属氧化物催化剂分子设计中的应用实例。     

催化元件变流检测矿井瓦斯

基于催化元件检测瓦斯的基本工作原理,提出了一种新的矿井瓦斯检测方法———变流检测法,设计出了相应的检测电路。通过性能试验得出,该检测系统具有检测范围大、稳定性好、响应速度快、抗激活和传感元件使用寿命长等显著优点。     

Cerium oxide/SnO2-based semiconductor gas sensors with improved sensitivity to CO

SnO₂-based semiconductor gas sensors have been successfully fabricated and tested for detecting carbon monoxide and methane. The sensitivity and selectivity of the sensors are tailored by incorporation of different additives such as platinum and cerium oxide. While platinum enhances the sensor response to CH₄, ceria suppresses its sensitivity in favor of carbon monoxide. The effect of operating temperature on the performance of sensors is reported. Addition of 10% cerium oxide in the SnO₂ sample leads to an insignificant response to methane even at an elevated temperature of 450°C, while its response to CO remains intact.     

拉曼光谱学用于监测变压器油中的甲烷气体的研究

提出了一种通过监测甲烷气体特征拉曼散射谱峰处的拉曼散射信号强度，以实现对变压器油中溶解甲烷气体浓度的在线测量新方法。     

Control of parallel dry methane and steam methane reforming processes for Fischer–Tropsch syngas

The ratio of hydrogen to carbon monoxide in the synthesis gas required for feeding to the gas-to-liquid Fischer–Tropsch (FT) process to produce liquid transportation fuel is about two. The dry methane reforming (DMR) process feeds carbon dioxide and methane and produces a syngas with a H₂/CO ratio of about unity. The steam methane reforming (SMR) process feeds water and methane and produces a syngas with a H₂/CO ratio of about four. This paper studies the plantwide control of a process with DMR and SMR units operating in parallel to produce FT syngas. The total methane fresh feed is split between the two parallel processes in the appropriate fraction so as to produce the desired H₂/CO ratio in the mixed syngas stream from the process.Both the SMR and DMR reactions are highly endothermic and the reactors are fired furnaces with combustion of fuel providing the endothermic heat of the reactions. Reactor exit temperatures are controlled by manipulating the flowrates of fuel to each furnace, with combustion air ratioed to the fuel. Dynamic reactor models assume tubular SMR and DMR reactors in which heat fluxes are determined by the heat generated in their associated fuel/air combustion reactors.The plantwide control structure effectively handles large 20% disturbances in throughput and large setpoint changes in the desired H₂/CO ratio (1.7–2.3).     

基于最小二乘支持向量机的瓦斯传感器非线性校正

依据瓦斯传感器样本,文章提出了一种采用最小二乘支持向量机辨识传感器逆模特征的校正瓦斯传感器非线性误差的方法,详细介绍了SVM回归估计校正方法和LS-SVM校正方法的原理。该方法不需逆模型函数形式的先验知识,能够保证找到的极值解就是局最优解,具有较好的泛化能力。实例应用表明,采用该方法校正后的传感器的检测精度可达到0.4%,效果令人满意。     

基于STM32和FPGA的激光甲烷检测系统设计

为了开发小型化的实用激光甲烷检测系统,设计了基于STM32单片机和FPGA的系统方案。FPGA实现系统中正交矢量锁相放大器和激光器调制驱动信号的产生。STM32负责半导体激光器温度控制,气体体积分数计算,通信接口等功能。设计的激光甲烷检测系统对4种标准甲烷气体进行了实际测试,在10%量程范围内示值误差不超过±0.2%。此方案可以作为激光气体检测系统的通用平台,实现对其他气体的测量。     

语音播报智能瓦斯报警器

介绍了一种具有语音播报及记忆存储功能的矿用瓦斯报警器及其整机工作原理,并着重阐述了其语音合成部分的软、硬件设计过程。     

锁相放大技术在光学式甲烷气体传感器中的应用

设计了一种基于近红外可调谐半导体激光吸收光谱的光学式甲烷气体传感器,传感器针对甲烷气体位于1653.722nm处的吸收谱线,应用锁相放大技术提取微弱的一次谐波幅度信号,实现对气体浓度的测量。重点分析了在光学式甲烷气体传感器中应用锁相放大的原理及关键技术。结果表明该传感器响应时间为10s,测量精度可达0.02%VOL。     

深海甲烷激光拉曼光谱原位探测器的研究

为了对深海痕量甲烷进行原位实时检测,研制出一种甲烷激光拉曼光谱探测器。介绍了拉曼散射的量子机理和拉曼光谱的特性,对合成甲烷水体进行了拉曼光谱测试,确定了水中甲烷的拉曼振动光谱范围在2 904~2 917 cm-1之间,且水分子的振动谱峰与甲烷的振动谱峰不重叠。利用这一特点可以设计甲烷激光拉曼光谱探测器,能原位、快速地分析和检测出海水中痕量甲烷组分,并通过耐压光纤将检测数据进行实时的远程传输,具有高灵敏度,适应4 000m深海高压低温环境作业的特点。     

光纤光栅调制式光纤甲烷气体传感器的研究

介绍一种检测甲烷气体的全光纤传感方法。基于甲烷气体的近红外吸收光谱，采用LED宽带光源，通过光纤光栅和压电陶瓷(PZT)对其进行波长调制，获得窄带出射光，检测二次谐波，实现甲烷气体浓度的较高灵敏度测量。     

基于无线瓦斯传感器的采煤机自动控制研究

本设计介绍一种新型无线瓦斯传感器的采煤机自动控制系统,通过在井下多分布无线瓦斯传感器系统检测周边的瓦斯浓度,一方面,可将各路采集数据处理显示出来并且超标声光报警,令一方面,可以将数据传输给主控器,通过分析各模块传来的检测数据来控制采煤机的速度,以减少瓦斯溢出量,也可以紧急预防瓦斯爆炸事件的发生,推动了井下开采系统的智能化。     

Optical fiber sensing element based on luminescence quenching of silica nanowires modified with cryptophane-A for the detection of methane

An optical fiber sensing element based on luminescence quenching of cryptophane-A/silica nanowires was successfully constructed and used to dynamically monitor methane gas at low concentration below 3.5% (v/v). The optical fiber device was designed to operate via luminescence reflection. The sensing properties of optical sensing element to methane at room temperature were characterized. The sensing element shows an intensive and stable blue luminescence when excited by UV light source at wavelength of 380 nm, and it is efficiently quenched by molecular methane. The response of the sensing element demonstrates excellent linear Stern-Volmer behavior at the fixed wavelength 439 nm within the methane concentration range between 0.1% and 3.5% (v/v). A detection limit of below 0.1% (v/v) is estimated for the methane sensing element. This newly developed methane sensing element has significant advantages over the currently available methane sensors such as fast response and recovery (within seconds), good repeatability, selectivity, and long-term stability.     

基于光谱吸收的瓦斯体积分数相关测量法探讨

提出了一种基于光谱吸收的瓦斯体积分数相关测量法,采用吸收气室作为传感头,通过调制参考气室内的纯甲烷气体压力来检测瓦斯体积分数。这种方案体积分数的检测分辨力可达1%,响应时间小于10m s,并从理论上对此方法进行分析和探讨。