管道内气固两相流颗粒浓度和风速测量方法的试验研究

根据两相流压降与颗粒浓度具有确定的依赖关系，提出了一种利用现有送粉管道，在同一管线上选择送粉特性有差异的两段管道在线测量风速和煤粉浓度的新方法，此法的优点在于不破坏原有管线及其阻力特性，特别适合于采用乏气送粉和直吹式制粉系统的火电厂现场使用，通过建立试验及相应的在线测量系统进行了试验，表明该法是可行的。     

电站锅炉一次风煤粉浓度测量方法的研究与应用

一次风煤粉浓度的准确测量对电站锅炉的安全经济运行起着重要的作用.乏气送粉锅炉一次风煤粉浓度测量一直是工程中的难题.本文研究了煤粉空气混合前后的参数变化与煤粉流量的关系,建立了通过混合前后的静压变化测量乏气送粉锅炉煤粉浓度的方法.本方法测量可靠,易于实施,在多台锅炉上取得良好的应用效果,满足了生产的需要.     

基于无线传感器网络的输粉浓度测量系统

针对燃煤电站输粉管道内煤粉浓度进行实时测量和调节的要求,介绍了一种基于无线传感器网络的输粉浓度测量系统。该系统以STC12LE5410AD和MSP430F149微控制器为核心,参照IEEE1451标准设计,主要由传感器模块、无线接口模块、智能传感器接口模块和网络适配处理器模块4部分构成,具有功耗低、测量准确等特点。实验结果表明,该系统运行稳定、能实现可靠的无线数据传输,从而较准确地测量出管道内的煤粉浓度值,对工业生产过程有重要意义。     

微波煤粉流量检测系统在长春一热的应用

一次风管道中一次风速和煤粉浓度是影响炉内燃烧工况稳定性和锅炉燃烧效率的重要原因之一。现采用基于微波能量法的煤粉浓度测量方法以及基于互相关法的一次风管道风速测量方法,对350 MW机组测量系统进行技术改造,给出了测量原理和系统构成,并应用于现场测量。现场调试及运行表明,该系统可以用于电站锅炉一次风管道风速和煤粉浓度的检测,具有较高的精度且本质防堵,为火电企业进一步实现优化燃烧提供了技术保障,具有较大的推广价值。     

用压降法测量管内颗粒浓度和风速方法的研究

根据两相流压降与颗粒浓度具有的确定的依赖关系，提出了压降法治测定管道颗粒浓度和风速的一般形式和特殊形式，通过对压降法不同形式的分析，找到了各自在测量上的特点及相互间的差别，指出在同一管线上选择送粉特性有差异的两段管道应用压降法的一般形式，可不破坏原有管线及其阻力特性，特别适合于采用乏气送粉和直吹式制粉系统的火电厂现场使用，建立了试验及在线测量系统并进行了试验，论证了压降法测量的可行性。     

压降法测弯管煤粉浓度中整流器性能数值模拟

煤粉浓度是表征输送管道运行状态的重要参数,电站锅炉输粉系统中弯头很常见。为了分析利用压降法测量弯管煤粉浓度时管道流场、整流器对弯管流速分布不均匀的改善效果及整流器的阻力系数,利用流体计算软件Fluent进行数值模拟研究。结果表明,Zanker整流器、非均匀整流器、AMCA整流器对速度不均匀分布的整流效果明显,不同整流器的整流效果不一样,从整流器后管道内速度达到充分发展管流所需直管段长度、整流器压力损失系数和磨损三方面综合考虑选择非均匀整流器。整流器压力损失系数也有差别并不和流通率呈正相关。整流器壁面形成动压高压区,形成的动压高压区压强与整流器流通率成正相关,高速的煤粉颗粒对整流器的冲击使整流器壁面磨损严重。     

用文丘里测量风粉混合物的浓度和流量

一次风煤粉浓度的可靠测量是电站锅炉燃烧优化和安全经济运行的前提条件.研究表明气固两相混合物流过文丘里时的差压与气体单独以相同流量流过文丘里时的差压存在一定的关系,这为气固两相文丘里流量计的研究提供了基础.气固两相文丘里流量计的应用与不断完善对提高锅炉参数的测量与控制水平具有重要的意义.     

1000 MW超超临界机组煤粉管道积粉堵塞原因浅析

火电机组中煤粉管道直接供应进入炉膛的燃烧介质,煤粉管道堵塞将造成着火不稳定,严重的将造成炉膛灭火甚至煤粉管道爆炸。现对煤粉管道积粉堵塞原因、检查经过、处理措施及防范措施进行浅析,可为同类机组提供借鉴。     

小型螺旋送粉器的设计

基于对目前应用较多的几种典型送粉器原理的比较分析,同时考虑实验室规模煤粉点火系统对供粉量的需求,设计了一款低送粉量、连续可调的螺旋送粉器。详细讨论了该螺旋送粉器的工作原理和结构设计,并对其性能进行了测试。     

电容式气固两相流浓度测量系统

本文介绍一种电容式气固两相流浓度测量系统,给出了具体的测量电极和测量电路。并采用所设计的电容式浓度测量系统在自行搭建的气力输粉系统上以面粉为媒质、在水平管道上对稀相气固两相流浓度进行了在线测量,获得了5×10^-5%体积百分比的面粉浓度分辨率。应用该系统对锅炉气力输粉管道中的气固两相流浓度进行实时在线检测与控制,对确保燃烧过程稳定,节能降耗和减少污染排放具有重大意义。     

Concentration measurement with thermal probe for pulverized coal in the pneumatic pipeline of power plant

The concentration measurement of pulverized coal in a pneumatic pipeline is a challenging issue in power plant. A thermal probe manufactured with abrasion-proof steel was developed for coal concentration measurement in such a situation. The probe generates 15 W of heat. This method is based on the heat transfer between the thermal probe and the gas–solid two-phase flow. Experiments were conducted in a horizontal pneumatic pipeline to assess the accuracy of the thermal probe, where the gas was air and the solid was pulverized coal with mean diameter of 65 µm. The wall temperature of the thermal probe was found to be dependent on both coal powder concentration and air velocity. A new heat transfer correlation was proposed in terms of the modified Reynolds and Nusselt numbers for the gas–solid two-phase flow across the thermal probe. In the range of coal powder concentration from 0.1 to 0.65 kg/kg, the standard deviation is 0.01 kg/kg for the thermal probe. The thermal probe has potential application for concentration measurement of pulverized coal in the pneumatic pipelines of power plants.     

Accuracy of cross correlation velocity measurements in two-phase gas–solid flows

The paper presents a detailed discussion of the errors of quantisation and sampling (conversion) caused by A/D converters and brought up for discussion on the basis of some original formulae derived. These converters are implemented in analogue–digital parts of measuring systems designed and produced to be in operation according to the cross correlation method of measurement of mean flow velocity of solid particles especially in pipelines of pneumatic transport. The discussion is based on an analysis of a real measuring system in which electrostatic flow probes were used to detect the smallest changes in charge carried by solid particles in pipes of pneumatic transport and in the air during their two-phase gas–solid flows. In the cross correlation of signals induced in electrostatic flow probes a non-intrusive electrostatic method is employed which is based on the phenomenon of electrostatic induction brought about by the time-varying charge of particulates in conveying pipes or by the so-called electrostatic flow noise. The conclusion of the discussion can be spread among other kinds of cross correlation method including the capacitive or electromagnetic methods based on the types of sensors named after the names of the methods. Certain excerpts in the paper are taken from or based in part on some passages from the author's monograph (Gajewski, 2010 [1]).     

Pulverized coal flow metering on a full-scale power plant using electrostatic sensor arrays

On-line continuous monitoring of pulverized coal in fuel injection pipes will allow power plant operators to optimize fuel conveying conditions and ultimately to achieve higher combustion efficiency and lower atmospheric emissions. This paper presents the design, implementation and trials of a prototype instrumentation system for the on-line measurement of pulverized coal on a full-scale power plant. An array of three identical arc-shaped electrostatic electrodes is housed in a sensing head to derive particle flow signals. Pulverized coal flow parameters such as velocity, mass flow rate and fuel distribution among the injection pipes from the same pulverizing mill are obtained by processing the signals and fusing the resulting measurements. On-plant demonstration trials on 560 mm bore pneumatic conveying pipes feeding a 600 MW boiler were undertaken following system evaluation tests on a 50 mm bore laboratory test rig. Experimental results demonstrate that reliable monitoring of pulverized coal flow parameters is achieved and that the system is able to track both transient and long-term fluctuations of pulverized coal flow in fuel injection pipes under real power plant conditions.     

Study and industrial evaluation of mass flow measurement of pulverized coal for iron-making production

This paper described a measurement system for mass flow measurement of pulverized coal in a blast furnace coal injection system. The system mainly consists of a volumetric concentration sensor and a velocity sensor. The concentration sensor is a capacitance sensor which has two pairs of concave electrodes placed axially on a piece of pipe of oxide of aluminum with different orientation to get being less affected by flow regime; the velocity sensor is also based on capacitance sensing principle, but uses “passing time difference method” which records the time at which each flowing cloud of coal powder passes through upstream and downstream sensor and then calculates the time difference to get the transit time for the cloud to travel between the two sensors. Both of the experiments in the laboratory and on the spot showed the measurement system has industrially acceptable performance.     

CGF法兰在平台立管维修中的应用

随着海洋石油工业的高速发展,海管的数量日益增多,其事故发生的概率也逐渐增加。由于海管类型、管径的差异、作业水深和环境条件的不同,所采取的维修方式也各不相同。本文系统地介绍了惠州油田的HZ32—3平台原油外输10in立管维修,不借助浮吊,仅利用平台有效作业空间安装的气动绞车,采用特殊的卡套式机械连接器CGF法兰,应用空气潜水实施立管泄漏段的更换维修。该方法是立管维修施工效率较高的作业模式,最大程度上达到降本增效的效果。通过对更换掉的旧立管进行分析和检测,提出在平台开发和生产中重点做好对飞溅区立管、泵护管和开排沉箱等关键设备的保护及定期检测的建议措施,可在一定程度上预防进入中后期生产的海上油田因海管泄漏造成的油田停产损失及环保风险。     

楔式单闸板阀门阀体锥度气动测头的设计

根据单闸板阀门阀体内腔的结构特点,采用气动测量方法对精加工阀体的重要配对工艺尺寸进行非接触测量。通过分析气动测头的测量原理,设计了高精度锥度气动测头及其校对规。     

高浓度粉体气力输送特性试验研究

在高浓度粉体气力输送试验台上，以压缩空气为输送介质，进行了两种粉体(黄沙、煤粉)的高浓度输送试验。试验结果表明，物料输送量和流化罐压力随着流化空气量的增加而增加；流化罐出口物料固气质量比随着流化空气量的增加而减小。试验还得到了物料输送量与流化空气量的关系式。     

步进控制在气动计量装置中的应用

为提高粒状物料计量装置气动回路的设计效率，提出了一种基于步进模块的设计方法。首先构建了一种由二位三通阀和双压阀组成的步进模块，并分析其结构原理；然后利用构建的步进模块设计出物料计量装置的气动回路，且详细阐述与计量装置每个动作相对应的步进模块的工作过程；最后利用Fluid-SIM软件对所设计的气控回路进行仿真分析。结果表明，执行元件能够按照设计要求完成物料的计量工作，验证了步进模块设计法的正确性与可靠性，为行程程序控制类气动回路的设计提供了一种快速有效的设计方法。