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大气颗粒物浓度在线监测方法研究 总被引:1,自引:0,他引:1
大气颗粒物浓度是大气污染监测中的一项重要指标.大气中的颗粒物,特别是PM10及其以下颗粒物浓度的监测一直是国内外专家关注的问题.本文提出一种采用振动原理在线测量颗粒物质量浓度的监测方法,替代了传统的离线监测技术,提高了监测工作的实时性和正确性. 相似文献
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由于抽取式监测系统存在不少问题 ,导致直接在烟道测量源水平气体浓度在线监测系统的发展。所谓在线系统即在没有改变烟气的组成并在颗粒物存在的条件下直接测量气体浓度的系统。在线监测系统要求能经受烟道环境条件的考验 ,结构简单 ,比抽取式监测系统的子系统要少。最初设计的在线监测系统 ,只能测量燃烧源排放烟气中污染物浓度在 5 0 0PPm和以上的气体。业已证明 ,只要按适合的质量保证措施进行维护 ,在线监测系统就能够顺利地、连续地运行。由于气体控制装置的出现 ,使排气中污染物的浓度降低。一些在线监测器要满足测量低浓度的污染… 相似文献
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烟气二氧化硫在线监测系统 总被引:1,自引:0,他引:1
为实现我国在短时期内控制烟气二氧化硫排放总量的目标,基于电化学原理,研制出一套适合我国国情的烟气二氧化硫在线监测系统(CEMS).该系统由两个子系统(二氧化硫质量浓度监测子系统和二氧化硫流速及流量监测子系统)构成.文中时系统的监测原理、方案等做了较详细的论述.同时,重点研究和介绍了利用"速度场常数"测量烟气平均流速的先进方法,自行研制出一套"速度场常数"自动检测装置,解决了烟道烟气平均流速自动监测的技术难题.经运行试验及检测,该系统监测结果稳定、可靠,达到国家监测标准,通过鉴定.该系统适用于我国烟气二氧化硫的在线监测. 相似文献
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王桂荣 《仪表技术与传感器》1996,(4):10-12
一种用于状态监测和故障诊断的新型声发射传感器已经研制成功。它基于全光纤法布里—珀罗干涉仪原理。其分辨率高达埃级,频率范围为100kHz~1.4MHz。由于信号光束和参考光束在同一根光纤中通过,所以消除了温度变化、微弯效应以及电磁干扰等环境影响,并具有很高的测量稳定性。 相似文献
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汽车尾气中的挥发性有机物(VOCs)是主要的人为排放污染源之一,排放到大气环境中的VOCs具有很高的反应活性,能够参与臭氧的生成,是形成二次有机气溶胶等污染物的重要前体物质。因此,研制开发适用于现场实时、在线检测VOCs的便携式分析仪器,是现代科学仪器发展的重要方向之一。本工作利用苯系物标准气体对自行研制的便携式膜进样真空紫外灯单光子电离飞行时间质谱仪整机进行性能测试,仪器的质量分辨率优于350,质量精度优于1×10-4,对苯系物的检测限可达μg/m3级,动态范围优于3个数量级,仪器的总质量小于25 kg。将仪器放置户外对汽车尾气进行现场测试,基于该仪器高时间分辨率的特点,初步研究了汽车尾气排放VOCs的变化趋势与发动机工作状态的相关性。该仪器有望应用于环境应急事故、现场长期监测、化工园区生产工艺过程监控以及无组织排放等领域。 相似文献
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On-line mass flow measurement of particulate solids in pneumatic conveying pipeline is a technically challenging area, where mass flow measurement presents a range of problems. These problems are not normally relevant to a single phase flow, but are always involved in gas–solids two-phase flows, like inhomogeneous distribution of solids over the pipe cross section, irregular velocity profiles, variations in particle size, moisture content, and deposition of fine particles on the inner wall of the pipeline. These variables may affect the response of a solids flow meter in ill-defined ways. All of these make the design and the calibration of solids’ mass flowmeter more difficult. Based on a review of non-invasive mass flow measurements of particulate solids, this paper summarizes and highlights several key issues, which often rely on structures of sensors or measurement methods, in indirect mass flow metering of pneumatically conveyed solids. They are: (i) spatial filtering effect; (ii) averaging effect; (iii) measurement resolution and sensitivity of array structures in tomography sensors. 相似文献
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A. A. Bespal’ko A. P. Surzhikov L. V. Yavorovich P. I. Fedotov 《Russian Journal of Nondestructive Testing》2012,48(4):221-225
Field measurements of electromagnetic emission intensity were performed by picket profiling in the Tashtagol mine workings. Increased emissions from rock contacts in the mine mass were found. The possibility of detecting latent structural distortions in mine workings by the developed method of monitoring and controlling the changes in the stressed-strained state of rock masses with the characteristics of electromagnetic emission was shown. 相似文献
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Electric capacitance tomography (ECT) is advantageous for online imaging of pneumatic conveying of solids. From the ECT images, the spatial distribution of the mass of the material can be displayed at a very fast speed. However, as the mass distribution and the permittivity of the solids simultaneously affect the values of the measured capacitance arrays, they cause a coupled effect on the ECT images. In situations where the permittivity of the solids is influenced by the moisture, and this influence cannot be separated from the influence of the mass, or cannot be accounted for by an appropriate means, the measurement will be erroneous, as ECT images are usually interpreted as the distribution of the mass alone. This study aims to tackle the problem by an attempt to decouple the combined influence of the mass and the permittivity. A sensor of narrow electrodes is designed for the purpose of detecting only the variations in the permittivity. Simulation and experimental results both demonstrated that the influence of the permittivity and the mass of the solids can be decoupled under certain conditions, which provide a mechanism to correct the possible errors due to the unknown variation of the solids permittivity, or moisture. 相似文献
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The triboemission behavior of charged particles was measured under boundary lubrication of saturated hydrocarbon liquids during scratching of various solids by a diamond stylus. The solids tested were the metals Cu, Al and Fe, ceramics Si, ZrO2, Si3N4, Al2O3, soda lime glass and mica, polymers of 6, 6-nylon and PTFE. Saturated hydrocarbons of n-hexane, n-undecane and n-hexadecane were used as lubricating oils. Triboemission occurred in bursts and ceased abruptly as scratching was started and stopped. The emission intensity of the charged particles depended closely on the kinds of solids, especially on their insulating properties, with an increase of emission intensity in the order of conductor < semiconductor < insulator. The emission intensity decreased as the hardness of the solids increased. These emission characteristics under the boundary lubrication condition are principally the same as in dry friction under ambient conditions. 相似文献
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Lubricant distillates undergo different stages of refining in order to produce the quality required of base stock for lubricating oil formulations, incorporating different additives in various doses. It is essential to monitor the degree of refining at different stages and additive response in base stocks, using fast and accurate techniques. FT-NMR and FTIR techniques offer a new dimension to the monitoring and characterisation of lubricant distillates and base stocks. In the present paper, an attempt is made to demonstrate the application of these techniques to deriving some average structural parameters and to correlate them with various physico-chemical characteristics of lubricant distillates and base stocks. These correlations could be used to optimise various process parameters during the refining of lubricant distillates. If the process parameters are constant, such correlations could be used to predict the quality of the base stocks obtained from any change in the composition of the lubricant distillates. Various applications of FTIR in base oil characterisation and its processing are also reviewed. 相似文献