简析燃煤电厂SCR脱硝技术催化剂

目前控制氮氧化物排放的主流技术是选择性催化还原法(SCR),然而,SCR脱硝系统中催化剂又是关键,本文介绍了SCR脱硝技术中催化剂的基本概念、种类及其特性,同时阐述了国内外脱硝产业发展现状,阐明了我国脱硝产业发展的关键是催化剂的生产。     

电厂脱硝改造技术应用

为满足国家"十二五"相关环境保护的要求,进一步降低NOX排放,改善当地大气质量,需要在燃煤锅炉尾部加装脱硝装置。烟气脱硝应用较多的是选择性催化还原法(SCR)、选择性非催化还原法(SNCR)及SNCR/SCR联合技术,由于高的还原率及技术的广泛使用,选择性催化还原(SCR)已成为目前国内电厂烟气脱硝的主流技术。本文介绍了SCR的脱硝技术,分析了选择性催化还原(SCR)技术的脱硝原理、工艺流程、设备布置和系统组成。     

SCR脱硝工艺计算实例分析

NOx是世界上主要的大气污染物之一,随着火电行业的不断发展,我国NOx的排放量不断增加。对此,我国陆续出台一系列指标,严格控制NOx的排放。NOx控制技术较多,其中,SCR技术最为成熟、应用范围最广,具有处理效率高、反应温度低、运行可靠等优点。SCR工艺计算中,关键工艺计算主要包括脱硝效率、还原剂消耗量、稀释风量、催化剂体积和SCR反应器尺寸。本文简要介绍了SCR的工作原理,并以乌鲁木齐市某热电厂为例,详细介绍SCR关键工艺的计算方法。     

催化法去除氮氧化物的研究进展

综述了国内外氮氧化物的催化去除方法,着重讨论了SCR法和SCO法.在SCR法的分析中,针对传统还原剂NH3,通过改进催化剂的方法提高NO的转化.此外讨论了新型还原剂,如炭、低碳烃、CO和氢气的SCR法去除氮氧化物的研究进展.在SCO法的分析中,阐述了分子筛、活性炭、金属氧化物等不同类型催化剂催化氧化NO的特点及存在的问题.     

SCR氧化燃煤烟气中气态单质汞的研究进展

燃煤和有色金属冶炼是我国两个最大的人为汞释放源,联合选择性催化还原脱硝技术(SCR)和烟气脱硫技术(FGD)可以对烟气汞排放实施控制,是一项有潜力的燃煤电厂烟气净化技术.综述了SCR氧化燃煤烟气中气态单质汞的催化机理,总结了燃煤种类、催化剂种类和烟气组分对SCR催化氧化气态单质汞性能的影响.     

基于低温条件的烟气脱硫脱硝技术应用研究

<正>烟气脱硫脱硝技术的探索是为了我国经济的进一步的发展,为了更好的将这项技术广泛的应用到锅炉行业当中,我们在实践的过程中就要进行技术的发现和技术的不断改进。低温条件烟气脱硫脱硝新技术低温SCR技术SCR技术就是选择性催化还原技术,这项技术是控制电站锅炉氧化氮的排放的重要技术。对于低温SCR技术国内外已经展开了深层的研究,主要研究的领域就是对于低温SCR催化剂的研究,其中包括低温催化剂和催化剂载体。     

中国燃煤电厂SCR技术的应用现状和发展

对中国燃煤电厂氮氧化物污染现状进行了分析,造成大气污染的主要污染物之一是氮氧化物,而氮氧化物的排放中有70%来自煤炭的直接燃烧.介绍了选择性催化还原法(SCR)技术及其在中国燃煤电厂的应用,并指出了中国燃煤电厂SCR脱硝技术的发展方向.     

球团烟气SNCR/SCR联合脱硝喷枪位置优化设计

介绍了以氨水为还原剂，SNCR/SCR联合脱硝在某年产120万t链篦机-回转窑球团烟气上的模拟应用。利用CFD技术重点分析了链篦机PH段及SCR反应器内烟气流场，探索喷枪最佳安装位置。结果表明，在链篦机PH段B区开孔，标高为22.1 m/21.5 m是相对较好的布置方式；在SCR反应器入口烟道段，喷枪应安装至烟道中部，间隔1.2 m，效果最佳。该模拟研究为今后球团烟气的改造提供了理论基础。     

基于多孔介质模型的SCR烟气脱硝反应器流场的数值模拟

本文通过对SCR——选择性催化还原法脱硝技术原理的介绍,结合多孔介质模型的模拟计算理论,提出对于模拟蜂窝形状的SCR催化剂床层,因其蜂窝形状结构、边界条件设置及网格划分过于复杂,可以采用多孔介质模型进行数值模拟。在此基础上,利用工程仿真实例,指出了可以采用CFD模拟软件对SCR反应器导流、整流部件进行优化设计,其优化过程具有良好的快速性,优化结果具有较好的实用性,对火电厂脱硝系统导流结构装置的设计具有现实指导意义。     

SCR烟气脱硝技术在油气混烧锅炉上的应用

以油气混烧锅炉为例,从锅炉运行现状、脱硝技术路线和脱硝改造方案等方面,对SCR脱硝工艺技术进行简要介绍,讨论了SCR烟气脱硝技术在实际应用中需要注意的问题及取得的环保效益,为今后类似的工程项目建设提供参考和借鉴。     

不同种类片岩耐崩解特性试验研究*

为研究不同种类片岩耐崩解特性,以曼家寨东帮边坡3种片岩为研究对象,通过室内耐崩解性试验和薄片鉴定分析,研究3种片岩崩解物形态特征、破坏模式和耐崩解性指数的变化规律,同时探讨3种片岩崩解差异产生的机理。研究结果表明:3种片岩的崩解差异特性与其物质组成成分密切相关;在相同循环次数下,3种片岩的耐崩解性指数有如下关系,绿泥石化片岩＞云母石英片岩＞石英云母片岩;片岩的崩解模式分为表层剥落、顺节理面劈裂、次生劈裂3个类型;从崩解微观机制上分析,岩石内部孔隙度这一微观结构的损伤是引起片岩崩解的内在因素,孔隙度的高低影响着损伤因子的大小,从而导致3种片岩崩解特性呈现差异性。     

Evaluation of an integrative masters program in occupational health at the Tel Aviv University Medical School

Tel Aviv University conducts the Master's program in occupational health in Israel. The program is composed from three different disciplines: occupational physicians, industrial hygienists and psychosocial workers. The aim of the program was to train graduate academic professionals for the developing occupational health system in Israel. The program is a two year study, opens every second year and accommodates about thirty students per class. After the second class, comprehensive assessment was conducted by the Unit of Medical Education. The evaluation was done by means of personal interview of class leaders, teachers and students, using structured questionnaires. A similar evaluation was again conducted after graduation of the fourth class in 1993. Three aims of the assessment were defined: to learn about the students' and teachers' expectations of the course, the level of integration achieved between the occupational health professionals in the three disciplines; and to evaluate the employment status of the graduates upon completion of the course. Following the first evaluation, changes were implemented in the methods of student selection for the program. A new entering examination was constructed to ensure a common basic knowledge of the potential students in the three disciplines. Changes were also made in the curriculum regarding teaching hours and subjects. A major problem at that time was that most of the graduates could not find positions in the field, because of low awareness for occupational health in Israel. In the second evaluation done in 1993 a higher level of satisfaction of students and teachers from the program was noted. The average level of the accepted students was higher compared with those accepted earlier. Better and deeper integration between the three disciplines of studies was appreciated. More graduates of the program found jobs in the area of occupational health and there is a higher level of awareness of employers and high regards to the course.     

技术资源对生态足迹需求的影响

生态安全是生态承载力的“底线”,超过该临界值,生态安全就会崩溃。通过对生态足迹需求和供给的计算,得出该区域生态系统的供给量超过了/不足以该区域人们正常生活的需求量的结论。在生态足迹法中引入技术资源的生态足迹计算,全面评估在技术资源的影响下区域发展的可持续性。在地理信息系统的支持下,计算技术资源的生态足迹,结果表明2002年珠海的发展属于不可持续性;通过计算珠海2002—2020年生态足迹的时间序列值来追踪各个时点的可持续程度,弥补了生态足迹法中指标静态性的缺陷,结果表明2020年珠海发展属于不可持续性,但有了较大的缓解,其主要因为充分利用了技术资源提高劳动生产率、提高资源能源效率。技术资源是评估区域发展可持续性的不可忽视的重要因子,技术资源的生态足迹研究对于城市的生态规划和建设具有借鉴和参考价值。     

振动纤维栅除尘器中单纤维振动特性的研究

在振动纤维栅除尘器中,气流绕流纤维时旋涡脱落频率（Re＞40）与纤维的固有频率相近,发生同步效应,使振动纤维栅中的纤维产生共振响应。本根据弦的波动方程,运用振型叠加法计算纤维的振动响应,并与实验结果进行了比较。结果表明,纤维的共振幅响应与固有频率、阻尼比、旋涡脱落频率（Sr数）、流体的作用力有关,并给出了振幅表达式。     

Study of the propagation of kerosene explosions inside a partitioned vessel

The aim of this work is to present a simple modelling in order to predict the evolution of the thermodynamical characteristics of the combustion of kerosene droplets in each compartment of a closed or a vented vessel.A simple representation of the combustion phenomena based on energy transfers and the action of specific molecular species is presented.The fuel ratio of the mixture is defined by the experimental determination of the partial pressure of the kerosene vapors. The total mass rate of gaseous substances due to the difference of pressure between adjacent compartments or the surrounding atmosphere is calculated by the standard orifice equations. A calculation methodology is developed to simulate the transmission of the explosion from one compartment to another adjacent compartment in simple structures with a possible extension to complex multi-partitioned structures. The model allows the study in each compartment of the influence of various parameters such as the fuel ratio of the mixture, the size of the inner openings or the venting effects.Calculation and experimental results show that in all cases, overpressures appear in the adjoining areas to the ignition compartment.     

安全文化学核心原理研究

为进一步丰富安全文化学原理和完善安全文化学学科理论体系,进而促进安全文化学研究与发展,主要从组织层面出发,运用比较法与归纳法,对安全文化学核心原理开展系统研究。首先,根据安全文化与安全文化学的定义,给出安全文化学原理的定义,并指出安全文化学原理研究需注意的2个问题。其次,提炼并剖析安全文化学原理的7条核心原理,即累积效应、"中心-边缘"效应、过滤原理、传播原理、局部稳定原理、最小偏离角原则与牵引跨越原理。最后,构建安全文化学原理"三层"结构体系,并分析其内涵。结果表明,7条安全文化学核心原理之间彼此影响、相互促进,并可划分为3个不同层面,它们几乎涵盖安全文化学的所有研究内容,可显著促进安全文化学学科理论体系的发展和完善。     

穿层钻孔有效抽采半径的测定

钻孔的有效抽采半径是在矿井瓦斯抽采设计中的一个关键性参数。准确测定钻孔的有效抽采半径,有利于合理布置瓦斯的抽采钻孔,实现最佳设计、最小工程量和最优抽采效果。根据实际煤层的存在条件,首先采用压降法对矿井试验区内穿层抽采钻孔有效抽采半径和水力冲孔抽采钻孔有效抽采半径进行实测。然后通过Comsol Multiphysics数值模拟软件建立穿层钻孔瓦斯抽采的数值计算模型,所得模拟结果与现场实测数据基本一致。这证明了现场实测结果的正确性和方法的可靠性。该钻孔的有效抽采半径的测定结果可为金牛建业煤矿技改井二1煤层预抽煤层瓦斯的钻孔设计提供参考。     

安全激励对具从众动机的建筑工人不安全行为的干预作用

为了研究安全激励对具有从众动机的建筑工人不安全行为的干预作用，识别建筑工人不安全行为的影响及干预因素，分别对具有从众动机的建筑工人不安全行为发生机理、安全奖励和安全惩罚的干预机理进行假定。基于调研数据，采用SPSS和AMOS工具展开模型拟合。研究结果表明:安全激励对建筑工人不安全行为有一定的干预作用；奖励对从众动机建筑工人的安全动机的端正产生0.108的正向影响、对安全能力的提升产生0.121的正向影响；惩罚对从众动机的建筑工人的安全心理健康产生0.140的正向影响、对安全知识的学习产生0.250的正向影响。基于此，提出预防具有从众动机的建筑工人不安全行为的有效措施。     

Dynamics of dust explosions suppression by means of extinguishing powder in various industrial conditions

In industrial conditions, there are different kinds of installations endangered by an explosion of dust–gas mixtures. In order to prevent them from any consequences of potential explosions, active protection systems which use extinguishing powders, as the suppressing material, are more and more widely applied. It often happens that the industrial installations are additionally endangered by an action of mechanical vibrations. In the above-mentioned conditions, the extinguishing powder tends to aggregate, making the process of dispersing it in the protected areas more difficult.

The results of research into optimization of the shape, number of igniters and miniaturization of the explosive charge mass are presented. In case of occurrence of the mechanical vibrations in the installations that cause aggregation of the suppressing powder, the best solution was modification of the perforated combustion chamber located inside the extinguisher. As a result of that, a certain amount of gases generated in the course of combustion of the main charge is directed over the membrane, where the gases crash a layer of aggregated powder. Thus, the process of pushing the powder out from a container towards the dispersing head improves considerably and consequently increases the efficiency of the explosion-suppressing process.