取样器的改进

改进前取分解率样子是在四级筒下料管处打一洞,焊上一节铁管,取样时用一个接有铁柄的取样桶伸进洞口,平时取样口用盖子盖好。一般情况下由于系统为负压,盖子不容易打开,且取好样子的取样桶又不易从洞中取出。如果一旦系统出现正压,高温物料有可能在取样时从洞口喷出,后果不堪设想。为了保证取样工的安全,方便取样,我们对取样器进行了改进。     

用于在线分析的烟气取样探头

取样探头是水泥生产过程在线检测分析系统的组件之一,它旨在实现对工业流体样品的取样。一个好的取样探头的设计标准是：能在不改变工业流体典型化学组分的情况下完成对样品流的物理分离。     

化工装置取样系统设计

简述化工装置取样系统设计的重要意义及样品采集方法,列举了几类常见的取样系统流程设计及取样系统管道设计。     

氯含氢分析仪取样系统的设计

分析了氯舍氢分析仪的取样系统的特性,提出了6个设计要点：负压取样、样气干燥、设备及管路避光、管径设计、材质设计、尾气处理。设计的取样系统应用到实际生产中,运行平稳可靠,满足了安全生产的要求。     

炼油装置在线分析仪取样预处理系统的设计探讨

阐述了在线分析仪取样预处理系统在国内外研究的现状,介绍了取样预处理系统的各环节。针对炼油装置中取样预处理系统的多样性,结合国内外样品处理系统技术的最新发展和应用经验,对在线分析仪取样预处理系统的设计进行总结和探讨。     

煤化工取样系统设计实例

简述化工装置取样系统的设计原则,结合具体的工程设计实例,列举了煤化工各装置中取样形式,并阐述了各种取样形式在设计过程及取样过程中需要注意的问题。     

瞬时取样器的改进

我厂改进前的瞬时取样器是在下料管处打一个长方形洞,然后在洞的左右下方焊接一“凹”形导槽,上面插一块圆孤形钢制盖板。取样时把盖板向上提起,用一个接有铁柄的取样勺伸进洞口,取好样后再用盖板盖好。一般情况下由于系统为负压,     

超稠原油大罐分层取样装置改进型设计

超稠原油大罐分层取样装置一直是国内外高粘液体生产中常用的大罐取样装置,本文结合现场实际应用,针对原有分层取样装置提手、取样尺宜断裂、取样瓶宜掉落等问题,设计出一种改进型大罐分层取样装置,该装置使用方便、易于操作、取样效果好,有效满足了油田及化工日常生产的需要。     

自动取样系统机电控制常见故障的解决办法

自动取样站与X射线荧光分析仪等大型制样及分析设备已成为水泥工业质量在线控制的标准配置而推广使用。某水泥有限公司引进的自动取样系统在使用过程中能按１∶１０６的最终缩分比例连续获取在线样品，并自动将样品通过管道传输到百米之外的分析室，替代人工取样，充分发挥了取样站取样代表性强的特点，从根本上消除人工取样可能不定时等弊端，但由于该系统是典型的机电一体化设备，自动化程度高，零部件较多，任何一个部件工作不正常都可能导致设备停机，运行初期加上部分安装及制造的缺陷，造成运行故障频繁，影响生产的正常进行，经数年…     

化工装置循环取样系统的设计

结合现场所出现的取样系统问题,通过流程设计和流量计算、管径选择,提出循环取样系统设计的解决方案。     

Anisokinetic Shrouded Nozzle System for Constant Low-Flow Rate Aerosol Sampling from Turbulent Duct Flow

An anisokinetic shrouded nozzle system was designed for sampling particles at a constant low flow rate from a ventilation duct to an aerodynamic particle sizer (APS). Shrouded anisokinetic nozzles are a means for sampling from a moving airstream with higher particle transmission than with unshrouded isokinetic nozzles. This shrouded nozzle sampling system was evaluated in an experimental ventilation duct system. Aspiration and transport efficiency measurements were made for five particle sizes in the range 1–13 μm at each of three duct air speeds in the range 2.2–8.8 m/s. Under these conditions, the shrouded nozzle system showed improved performance compared to buttonhook isokinetic nozzles, especially for larger particles and higher air speeds. Measured transmission efficiencies through the shrouded nozzle sampling system were generally higher and more reliably predictable than those through buttonhook isokinetic nozzles. Model predictions of transport and aspiration efficiencies of the shrouded nozzle system showed good agreement with measurements over the entire range of experimental conditions. The shrouded nozzle sampling system could be used to measure concentrations in ventilation ducts with an APS for particles in the diameter range 1–13 μm.

Copyright 2014 American Association for Aerosol Research     

COMPARISON AND VALIDATION OF OHM AND SCEM MEASUREMENTS FOR A FULL-SCALE COAL-FIRED POWER PLANT

Mercury emission measurements were performed at a 250 MW coal-fired power plant using the Ontario Hydro method (OHM) and semi-continuous emission monitors (SCEM). Flue gas sampling was performed at the inlet of the air preheater and at the outlet of the electrostatic precipitator. The results indicated that there is some agreement between the OHM and SCEM measurements on the total mercury species. However, the SCEM results were not always in good agreement with the OHM measurements on the elemental mercury species. These discrepancies in elemental mercury concentrations are probably the result of the differences in the location of the SCEM and OHM probes, the temperature difference between the SCEM sampling probe and the flue gas, and the nonuniformities in mercury concentration over the flue gas duct cross section. The other factor that contributed to the deviation between the SCEM and OHM measurement results is the sampling method: the SCEM measurements were performed at a single point while the OHM probe was traversed over multiple points over the duct cross section and the results were averaged. The effect of the SCEM sampling probe temperature was investigated by designing a sampling probe that could be heated to the sampled flue gas temperatures. This resulted in improvements in the accuracy of the elemental mercury measurements by the SCEM system.     

COMPARISON AND VALIDATION OF OHM AND SCEM MEASUREMENTS FOR A FULL-SCALE COAL-FIRED POWER PLANT

Mercury emission measurements were performed at a 250 MW coal-fired power plant using the Ontario Hydro method (OHM) and semi-continuous emission monitors (SCEM). Flue gas sampling was performed at the inlet of the air preheater and at the outlet of the electrostatic precipitator. The results indicated that there is some agreement between the OHM and SCEM measurements on the total mercury species. However, the SCEM results were not always in good agreement with the OHM measurements on the elemental mercury species. These discrepancies in elemental mercury concentrations are probably the result of the differences in the location of the SCEM and OHM probes, the temperature difference between the SCEM sampling probe and the flue gas, and the nonuniformities in mercury concentration over the flue gas duct cross section. The other factor that contributed to the deviation between the SCEM and OHM measurement results is the sampling method: the SCEM measurements were performed at a single point while the OHM probe was traversed over multiple points over the duct cross section and the results were averaged. The effect of the SCEM sampling probe temperature was investigated by designing a sampling probe that could be heated to the sampled flue gas temperatures. This resulted in improvements in the accuracy of the elemental mercury measurements by the SCEM system.     

密闭环保取样系统的应用与改进

密闭环保取样器适用于石油、化工装置中对管道内工艺状况下的各种介质,尤其是有毒、有害、易燃、易爆等危害性的高中低压气液介质的无泄漏采样.取样器由箱体、采样瓶、快插、压力表、阀门、密封件及法兰组成.样品真实性强、准确性高、无残液、残气排放,有效地防止有毒、有害介质对操作者的伤害,同时不会污染环境,避免了易燃、易爆介质在采样...     

全自动汽车煤炭采制样机的研究

介绍了全自动煤炭汽车采制样机的构成模块;分析了车辆信息采集、三维坐标点选取、采样方式及采样点坐标的测量、采样系统编码模块、采样系统与其他系统的接口等功能;该系统的应用实现了煤炭采制样系统真正意义上的全自动控制,引领了采样机控制技术的发展方向。     

A Source Dilution Sampling System for Characterization of Engine Emissions under Transient or Steady-State Operation

With increasingly stringent regulations being placed upon engine emissions, an in-depth understanding of engine exhaust composition will be necessary to assess environmental and health impacts and to develop better methods of reducing emission levels. Source sampling systems have commonly utilized partial sampling techniques, which may introduce the potential for particle loss, and steady-state operation, which is incapable of imitating transient engine conditions. In order to simulate atmospheric dilution and aging conditions, maintain proportional sampling throughout temperature excursions during transient operation, and minimize particle loss, while representatively taking multiple samples from the exhaust flow, a full-partial-full source dilution sampling system was developed. The system consists of a critical flow venturi-constant volume system for primary dilution, a thermophoresis-resistant secondary micro-diluter, a residence time chamber, isokinetic sampling probes, multiple sampling trains, and control systems. Further, the system was designed to prevent particle loss and secondary reactions by reducing wall effects, implementing inert materials, optimizing smooth flow transition, and minimizing electrostatic forces. An examination of the system was conducted by performing a tracer study and by determining the variations in flow rates, gaseous concentrations, and PM mass measurements. Further, a statistical analysis was performed to study the capability and performance of the sampling system. The results suggest that the system was capable of collecting similar samples among the sampling trains and displaying sufficient agreement with a certification system. Therefore, the source dilution sampling system developed in this study is suitable for collecting representative samples from an exhaust flow under transient or steady-state conditions.     

Determination of a new sampling system based on exponentially weighted moving average

In this article, a new sampling system based on an exponentially weighted moving average statistic is proposed for the inspection of normally distributed quality characteristics. The proposed sampling system can be applicable for compliance testing. The performance measures of the proposed system are derived and analyzed. Tables are also constructed for determining the optimal parameters of both known and unknown standard deviation cases. An optimization problem is formulated as a nonlinear program in order to construct the tables in which the objective function used is the minimization of the average sample number and the constraints are related to the probability of acceptance at acceptable quality level and limiting quality level under the operating characteristic curve. The efficiency and advantages of the proposed sampling system are discussed over the existing variables sampling plans. Extensive tables are provided for industrial applications. Implementation of the proposed sampling system is discussed with the help of a real-time industrial example.     

Process identification for an SOPDT model using rectangular pulse input

A new method of process identification for a second-order-plus-dead-time model is proposed and tested with two example systems. In the activation of the example processes for the identification, a rectangular pulse input is applied to open loop systems. The model parameters are estimated by minimizing sum of modeling errors with the least squares method. The estimation performance is examined by comparing the output pulse responses from the example system and the estimated model. The performance comparison of the proposed method and two existing techniques indicates that satisfactory parameter estimation is available from the proposed procedure. In addition, the role of sampling time and the shape of input pulse is evaluated and it is found that the sampling time of less than 0.01 minute gives good estimation while the shape of input pulse does not affect the estimation performance. Finally, the robustness of the estimation in noisy process is proved from the investigation of the performance in the processes having various levels of noise.     

气固两相流中局部颗粒质量流率的测量新方法

Previous works have shown that the suction probe cannot be used to accurately measure the upward and downward particle fluxes independently. A new method using a single optical probe to measure the local solid flux is presented. The measurement of upward, downward and net solid fluxes was carried out in a cold model circulating fluidized bed (CFB) unit. The result shows that the profile of the net solid flux is in good agreement with the previous experimental data measured with a suction probe. The comparison between the average solid flux determined with the optical measuring system and the external solid flux was made, and the maximum deviationturned out to be 22%, with the average error being about 6.9%. These confirm that the optical fiber system can be successfully used to measure the upward, downward and net solid fluxes simultaneously by correctly processing the sampling signals obtained from the optical measuring system.     

四氧化二氮纯度快速化验初探

为探索四氧化二氮纯度(质量分数)快速化验的可行性,比较了安瓿球取样法和移液管取样法的精确度,研究了充氮时间、反应时间对纯度的影响。结果表明:安瓿球取样法精确度良好,纯度测定值可信;移液管取样法操作简便,但偏差较大,不适用于纯度分析;充氮时间、反应时间对纯度测定值均有一定影响,其中反应时间对纯度影响更大。