火电厂超低浓度烟尘监测方法探讨

目前,对于火电厂低浓度的烟尘测试方法很多,可没有一种切实可行的且符合国家标准规范的标准测试方法,本文通过不改变烟尘等速采样的原理,通过几种改进的采样装置进行对火电厂湿式电除尘出口的烟尘进行不同种类的仪器、不同的采样装置、以及采样吸附的滤膜或滤筒的测试,对得出的烟尘浓度结果进行比较,分析产生测量误差原因,对存在问题进行思考,测量技术中需要解决的问题等进行了论述,并提出可行的火电厂超低浓度烟尘的监测方法。     

降低300MW机组锅炉烟尘排放浓度

本文针对电除尘器阴极线设计缺陷和单相电源效率低等方面的原因分析,详细阐述火电机组降低电除尘器烟尘排放浓度和提高除尘效率的改造方法,实践证明电除尘器阴极线和控制电源改造后,环保和节能效果显著,对同类型机组电除尘器改造具有借鉴意义。     

布袋除尘器

粉尘排放一直是世界各国关注的焦点,随着我国国民经济持续稳定地发展,电力工业和钢铁工业也在快速增长,每年排放的烟尘和二氧化硫的数量非常巨大,严重污染了环境。静电除尘器和布袋除尘器在我国应用比较普遍,但采用电除尘器加干法脱硫或只采用电除尘器时却很难满足排放要求。只有布袋除尘器能够将烟尘排放浓度控制在50mg／Nm^3以内,最高可以控制在10mg／Nm^3,能适应排放要求。     

燃煤电厂“超净排放”——湿式除尘器

"超低排放"是燃煤电厂当前改造的首要任务,烟囱出口含尘量实现2014年7月1日实施的《火电厂大气污染物排放标准》要求的燃气轮机排放标准。即满足烟尘排放浓度≤5mg/m3。目前已运行的燃煤机组的烟尘处理均采用静电除尘器、电袋除尘器或布袋除尘器,处理全烟气量时的烟囱出口烟尘排放浓度为20mg/m3~30mg/m3;脱硫采用石灰石-石膏湿法脱硫工艺系统或海水脱硫系统;保证在锅炉BMCR工况下脱硫效率不小于95%。如实现烟囱出口烟尘排放浓度≤5mg/m3首选湿式电尘器。     

电袋复合除尘器在电厂除尘增效改造的实际应用

目前,大气污染形势严峻,为了达到新环保标准的要求,有些老旧的电除尘器已经不能满足运行要求,必须改造才能高效除尘。该文分析了电袋复合除尘器处理烟尘排放浓度可以保证在20mg/Nm3以下的机理。针对浙江横店热电有限公司#1炉除尘升级改造项目,将电厂内原有的运行多年的电除尘器改造为电袋复合除尘器,介绍了该项目的改造目标、改造方案和改造后的效果,肯定了电袋除尘器对烟尘行业所做的巨大贡献。     

燃煤烟气中Hg迁移转化特性研究

研究了300 MW煤粉锅炉系统选择性催化还原（selective catalytic reduction,SCR）、低低温电除尘器、海水脱硫、湿式电除尘器等超低排放设施在不同工况、不同煤种情况下的Hg迁移特性和脱除能力。结果表明：各工况下总汞排放浓度为1.16~2.90 μg/m³。最终排入大气中的汞主要以单质汞存在,还有少量氧化态汞,颗粒态汞被全部脱除;汞主要是在海水法烟气脱硫中被去除的,低低温电除尘器、海水脱硫、湿式电除尘器对总汞平均脱除率分别为25%、62%、37%;Hg²⁺占比是影响烟气中汞脱除效率的关键,气相中较高的Hg²⁺份额有利于在电除尘器和海水脱硫装置中获得较高的脱除效率;在该配备SCR脱硝、低低温电除尘器、海水脱硫、湿式电除尘器等超低排放设施的300 MW煤粉锅炉电厂中,总汞平均脱除率约为83%,能够实现较大程度的汞脱除。     

哈尔滨市燃煤工业锅炉烟尘排放规律探讨

通过在不同负荷情况下对供暖及工业生产用的燃煤工业锅炉进行烟尘排放测试的结果，探讨了低负荷间歇运行燃煤工业锅炉的烟尘排放规律。     

低负荷间歇运行燃煤工业锅炉烟尘排放规律的探讨

通过对燃煤工业锅炉在不同负荷情况下的烟尘排放测试,探讨了低负荷间歇运行燃煤工业锅炉的烟尘排放规律。     

烟气连续排放监测系统相对准确度的测试评估

烟气连续排放监测系统（CEMS）测试的数据作为排污收费的法定依据，但大多数已经安装的CEMS存在数据漂移超过规定、准确度低等问题。以某火电厂安装的CEMS为对象，在不同的锅炉负荷状态下测试其SO2／NOx及烟尘排放子系统，评估其相对准确度。当SO2／NOx监测子系统相对准确度超出标准要求时，要作数据修正，使烟尘测量相对准确度符合法规。为保证测量数据的准确性，CEMS应定期进行相对准确度及校准漂移的测试。     

复合电袋除尘器原理及改造

随着国家环保要求的不断提高,对烟气污染控制要求的日趋严格,老式静电除尘器粉尘排放浓度难以达到环保要求,复合电袋除尘器结合静电除尘器及袋式除尘器的优点,目前得到广泛应用,为提高电厂除尘效率,南屯矿电厂首先将3#电除尘器改造成复合电袋除尘器,改造后除尘效率明显提高,烟尘排放浓度低于环保要求,改造效果显著。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。