Limestone surfaces in built-up environment as indicators of atmospheric pollution

The concentration of sulphate on limestone surfaces of the external walls of churches in Malta is shown to be related to their position and distance from a power station, the main local point source of sulphur dioxide pollution. Limestone powder collected from these surfaces was examined for the presence of particles which, under low-power optical microscopy, appear as shiny black amorphous bodies which were interpreted as soot particles; the abundance of these bodies was expressed as a black particle count (BPC). The degree of sulphation and BPC were shown to be correlated with each other and both appeared to be strongly dependent on the prevailing wind. The BPC contour map indicated an important contribution to the parameter from vehicular traffic. It is suggested that the degree of sulphation and BPC of limestone surfaces from the built environment should function as environmental indicators of the relative air quality with respect to SO₂ and soot pollution. This data is possibly more accurately representative of the relative long-term air-quality status of different areas of habitation than that deduced from single or episodic measurements of atmospheric pollutant levels.     

采暖锅炉房烟道噪声治理

本文分析了采暖锅炉房烟道噪声的来源并介绍了实用的控制方法。     

再生浆造纸污水处理与闭路循环实践

分析了不同品种的再生浆造纸工艺及给排水流程 ;采用锅炉烟气处理脱墨黑液 ,漂白废水用于废水脱色 ;采用絮凝沉淀、过滤与化学处理相结合的方法处理综合污水。实现废水多级回用 ,循环水率达 80 %～ 90 % ,少量废水达标排放 ,投资和运行费用可节省近 5 0 %。     

手动加煤燃煤机在倒焰窑烟尘治理中的应用

燃煤型倒焰窑排放的烟法浓度高，处理难度大，已成为大气治理中的新热点。采用实用新型燃煤机，改变煤的燃烧方式使其完全燃烧，从而使燃煤烟气污染得到有效的控制达标排放并节约能源。     

水蒸气对层流甲烷/空气扩散火焰中烟黑生成的影响

空气中水的存在会严重影响烷烃类扩散火焰中烟黑的生成,研究氧化剂流中水对烷烃类火焰的影响,对污染物控制及火灾扑救具有重要意义。模拟采用24步简化机理的有限速率化学反应模型、Moss-Brookes烟黑模型及Discrete Ordinates(DO)辐射模型,研究在空气中加入水对甲烷/空气层流伴流扩散火焰的影响,其中烟黑模型包括烟黑的成核、表面增长和氧化。结果表明,伴流空气中的水蒸气会降低火焰的温度、抑制烟黑的生成。这是因为:一方面,水蒸气降低了甲烷燃烧的温度,火焰温度的降低导致化学反应速率减慢,烟黑成核和表面生长速率随之降低,火焰中烟黑质量分数便减少;另一方面,由于水蒸气的加入使化学反应OH+H_2 H+H_2O(R(15))逆向反应加速,继而导致OH生成量增加。但由于氧气浓度降低使火焰体积增大,OH的浓度降低。从而导致烟黑的氧化速率降低,烟黑生成量增加。由于水蒸气的化学效应小于其温度效应,总体上烟黑质量分数降低。最后对比了模拟结果和试验结果。     

Procedure for assessing hardware safety integrity in legacy systems

Functional safety is related to the safety functions of a safety-related system that uses electrical/electronic/programmable (E/E/PE) devices such as sensors, logic solvers, and final elements. A legacy system is a safety-related system which offers safety functions but which was not designed to comply with the IEC 61508 standard. This paper presents a procedure for assessing the hardware safety integrity of a legacy system so as to confirm its functional safety. The procedure defines the systematic relationship between the safety function and hardware system using a function-structure map (FSM) and assesses the hardware safety integrity centered on the safety function. The proposed procedure is applied to a boiler control system of a fossil-fuel power plant.     

武钢自备电厂2#锅炉前屏过热器爆管原因分析

从运行管理上对武钢自备电厂WGZ670/13.78型锅炉前屏过热器爆管原因进行了分析,并提出了预防的对策.     

浅谈油烟的危害以及相关标准的修订

伴随着经济的繁荣和人民物质生活质量的提高,餐饮业日益繁荣起来,再结合中国素来"民以食为天",传统饮食文化的特殊性及复杂性,导致烹饪过程复杂,同时也带来了各种各样的油烟污染问题。油烟已经成为继噪声、尾气、沙尘之后的又一大污染问题,并且成为百姓环保投诉的热点问题之一。《饮食业油烟排放标准》(GB18483-2001)是目前我国环保行业监测饮食业油烟的唯一标准方法,在实际工作中存在一定的局限性和不完备性,对现行标准进行修订势在必行。     

Catalytic combustion of soot over ceria-zinc mixed oxides catalysts supported onto cordierite

Modified substrates as outer heterogeneous catalysts was employed to reduce the soot generated from incomplete combustion of diesel or diesel/biodiesel blends, a process that harms the environment and public health. The unique storage properties of ceria(CeO2) makes it one of the most efficient catalysts available to date. Here, we proposed that ceria-based catalysts can lower the temperature at which soot combustion occurs; more specifically, from 610℃ to values included in the diesel exhausts operation range(300–450℃). The sol-gel method was used to synthesize mixed oxide-based catalysts(CeO2:ZnO); the resulting catalysts were deposited onto cordierite substrates. In addition, the morphological and structural properties of the material were evaluated by XRD, BET, TPR-H2, and SEM. Thermogravimetric(TG/DTA) analysis revealed that the presence of the catalyst decreased the soot combustion temperature by 200℃ on average, indicating that the oxygen species arise at low temperatures in this situation, promoting highly reactive oxidation reactions. Comparative analysis of soot emission by diffuse reflectance spectroscopy(DRS) showed that catalyst-impregnated cordierite samples efficiently oxidized soot in a diesel/biodiesel stationary motor: soot emission decreased by more than 70%.     

锅炉烟尘、烟气监测质量控制探讨

针对锅炉烟尘、烟气监测质量控制问题,结合实际情况进行分析。