燃煤电厂烟气脱白可行性分析

目前我国大多数燃煤电厂均采用石灰石-石膏湿法脱硫工艺进行烟气脱硫,脱硫后的饱和湿烟气直接排放后易形成"白色烟羽"。对白色烟羽形成的影响因素进行分析,并对当下主流的脱白治理技术的特点及其原理进行了阐述、对比,同时结合最新电力行业超低排放(深度治理)标准,分析烟气脱白对不同组分烟气的净化效果,对目前燃煤电厂即将实施的烟气脱白和烟气深度治理具有一定的参考价值。     

应用于湿法脱硫烟气的脱白工程技术探讨

燃煤机组的烟气经过湿法脱硫设备后直接排放容易形成白色烟羽。白色烟羽中携带了极细微颗粒物和气溶胶,对环境造成了负面影响。目前国内部分地方政府将燃煤机组烟气脱白写入地方环保标准。相关企业被要求采取技术措施消除白色烟羽。讨论了白色烟羽的形成和消除机理,通过冷凝降低烟气含湿量,提高排烟温度,可有效消除白色烟羽。结合烟气脱白工程成功案例,介绍了常用烟气脱白工程技术,为白色烟羽治理提供了思路与参考。     

燃煤电厂湿烟羽治理技术研究进展

湿法脱硫方式在我国燃煤电厂的脱硫系统中占主要地位，其中以石灰石–石膏湿法脱硫方式应用最多。湿法脱硫后的烟气通常为湿饱和烟气，若烟气在排放时环境的温度及湿度较低，则会在烟囱口产生“湿烟羽”现象。湿烟羽一般呈白色或灰色，含大量水汽及污染物，湿烟羽的出现对环境及人体健康产生危害。因此企业在采用脱白技术进行排放改造将会减少烟气中污染物的排放，使烟气更好地扩散。为了更好地了解湿烟羽现象，帮助待改造企业选用适合自身的技术路线，本工作对湿法脱硫工艺及湿烟羽形成原因进行了简单介绍，对国内部分地区出台的有关政策进行了汇总，并综述了湿烟羽特性的研究现状(包括湿烟羽的长度、抬升高度及消除特性)。湿烟羽的控制技术较多，主流技术可分为烟气冷凝技术、烟气加热技术及烟气冷凝再热技术，应用温湿图对各控制技术的原理进行解释，根据控制技术的分类对各类别下的应用进行了综述，提出控制技术复合使用的可能，在节能及经济性允许的前提下，各企业应尝试更多技术路线，为湿烟羽的治理拓宽道路。     

超低排放背景下烟气消白技术路线研究

超低排放背景下燃煤电厂大多采用湿法脱硫装置,装置出口饱和湿烟气排放后一般会在烟囱出口形成湿烟羽,对生态环境及人体健康造成不利影响。本文基于切线法对烟气及环境空气状态进行计算,确定湿烟羽消除的临界温度及混合空气当量比,比较不同烟气消白技术路线的适用环境条件及技术参数。研究结果表明,环境温度越低、相对湿度越高,湿烟羽消除难度越大。环境相对湿度为60%,脱硫塔出口烟气温度为50℃时,不采用任何措施的前提下可实现无湿烟羽排放的临界环境温度为37. 3℃,可见在常见环境条件下,调整湿法脱硫装置出口烟气状态参数以消除湿烟羽是有必要的。假设可适用的烟气最大降温幅度为30℃,最大升温幅度为30℃,仅采用烟气加热技术可消除湿烟羽的临界环境温度为12. 9℃;仅采用烟气冷凝技术可消除湿烟羽的临界环境温度为8. 7℃;采用烟气冷凝再热技术可消除湿烟羽的临界环境温度为-12. 9℃。对于空气加热混合技术,基于切线法对空气烟气混合过程进行热平衡计算,确定可消除湿烟羽的临界空气当量比。将烟气加热、烟气冷凝及空气加热技术组合使用可拓宽烟气消白适用的环境条件。     

燃煤电厂白色烟羽控制研究进展

部分地方政府出台政策要求燃煤电厂进行白色烟羽的控制，引发广泛关注。为深化白色烟羽控制研究，本文介绍了白色烟羽形成及消除机理，概述了白色烟羽控制技术，包括烟气加热、烟气除水及烟气除水再热，其中水媒式GGH、冷凝器、浆液冷却技术应用最多。进一步，对控制技术进行总结，指出现有控制技术具有一定的局限性，只能在特定环境条件下完全消除白色烟羽。以满足政策要求和环境条件为基础，兼顾技术局限性、工程实际及经济性，提出了技术选择的路线。此外，对环境影响进行了分析，指出白色烟羽控制的环境效益不明显。最后，对白色烟羽控制进行了预测，指出白色烟羽控制需灵活化、差异化、区域化，避免强制化、一致化、全面化。     

燃煤电厂湿法脱硫消除白色烟羽的主要技术路线分析

近两年来,燃煤电厂的烟羽消白突然出现在公众视野,主要针对湿法烟气脱硫的尾气进行处理,使烟囱出口的"白色烟气"减少或消失。目前市面上应用的主流技术冷凝方案有两种,一种是浆液冷凝,另一种烟道冷凝,如果想要达到更好的效果,需要在后续烟道中增加再热装置,进一步提高消白效果。本文主要针对市面上主流冷凝法消白进行分析介绍。     

水泥工业窑尾烟气脱白技术分析

目前,我国有一部分水泥厂采用石灰石-石膏湿法脱硫工艺进行烟气脱硫,脱硫后的饱和湿烟气排入大气后,水蒸气冷凝形成白色烟羽对环境造成了一定的污染。该文结合水泥工业窑炉湿法脱硫的特点,对白色烟羽的治理机理和工艺路线进行了阐述,对目前水泥厂烟气脱白和治理二次污染具有一定的参考价值。     

冶炼烟气新型喷淋除湿脱白工艺探索

冶炼烟气经湿法脱硫后通过烟囱排放,会产生湿烟羽。技术人员对湿烟羽的形成机理进行研究,并提出一种新型喷淋除湿脱白技术。该技术工艺流程为喷淋冷凝—换热—气液分离—烟气再热。该技术通过直接喷淋冷凝的方式,将脱硫后的排烟温度降至40℃以下,使烟气中的水蒸气冷凝排出;再将气体加热升温至80℃排放,保证良好的脱白效果。     

湿法脱硫烟气水回收技术研究进展

湿式石灰石石膏法是目前应用最为广泛的烟气脱硫方法,但其涉及的水问题不可忽略,雾霾、白色烟羽、石膏雨等环保问题均与水问题有关。同时烟气中水资源含量大,实现烟气水回收对于电厂节水意义重大。笔者论述了现有烟气中水分来源以及烟气水回收技术,分析了烟气水回收技术的原理、优缺点和研究应用情况等。实现水回收的方法有冷凝法、膜法以及吸收法。冷凝法水回收技术回收的水质较差,具有一定腐蚀性,但水回收量较大;吸收法水回收技术系统较为简单,回收水质也较好,但有吸收溶液随烟气带出的风险;而膜法水回收技术的回收水质好,不涉及污染物排放,但其回收水量仍有提升空间,清理、减小甚至防止污堵是限制该技术发展的关键。电厂须根据实际情况选择具体的冷凝技术,在电除雾器运行状况稳定、除雾效果好的电厂可优先考虑膜法水回收技术;有余热回收需求的电厂,可优先考虑冷凝法。最后指出从根本上解决水问题的方法是转变烟气脱硫方式。干法脱硫由于不涉及废水问题,也不会增加烟气中水蒸气含量,同时避免了腐蚀等问题,是烟气脱硫技术中最有潜力的方法之一。     

蓝天工程实施重点燃煤电厂烟气脱硫

据悉，天津市在重点实施燃煤电厂锅炉烟气脱硫工程的同时，从今年起至2010年，将重点实施燃煤电厂烟气脱硫项目及20t/h及以上燃煤锅炉高效脱硫除尘技术改造．按照蓝天工程分年度计划完成全市455台10t／h以上燃煤锅炉烟气高效脱硫工程．以确保二氧化硫排放达到天津市《锅炉大气污染排放标准》Ⅱ时段标准要求。     

Application of a high-temporal resolution method to estimate ammonia emissions from farmland

A viable method—open-path tunable diode laser absorption spectroscopy (OPTDL) in conjunction with a backward Lagrangian stochastic (bLS) dispersion model—has been used for micrometeorological monitoring of ammonia fluxes. In this technique, the gas concentration measured with the OPTDL sensor is used to infer the surface emission rate with the aid of dispersion model calculations. On the basis of numerous assessment experiments and field trials, several beneficial strategies for using the OPTDL technique properly to monitor atmospheric NH₃ concentrations in the field have been summarized. Theoretically, the location of the concentration measurement can be anywhere in the emission plume, but in practice, the concentration measurement position must be carefully selected to avoid making measurements which are on the periphery of the downwind plume or are affected by obstructions. To obtain accurate estimates, periods with low friction velocity or extreme atmospheric stability, where Monin–Obukhov similarity theory-based relationships are invalid, or unrepresentative estimates due to unsuitable wind direction, should be excluded. A validation experiment showed that there was no significant difference between the ammonia emission rates obtained by the micrometeorological mass balance method and those obtained by the bLS model combined with the OPTDL technique. This study also indicated the potential of the bLS and OPTDL technique for investigation of diurnal emission patterns and environmental influences.     

玻纤企业环保工作杂谈

天津市玻璃纤维总厂20多年来,消除了三大公害：一是玻纤废丝28 500 t回收制球,节约创效1 731万元;二是用氧化铈取代剧毒的白砒作澄清剂,累计取代360 t;三是增塑剂回收800 t,节约560万元。这些工作达到了兴利除害,变废为宝,综合利用,惠及民生的目的。     

Impact of agitation and aeration on hydraulics and oxygen transfer in an aeration ditch: Local and global measurements

In urban waste water treatment plants one of the most developed processes to treat pollutants is the activated sludge basin. The aim of this paper is to present results on the hydraulics and aeration performance of an aerated basin at pilot plant scale. Local gas retention, gas velocity and bubble size have been measured and linked to the classical global measurements of oxygen transfer coefficient and of horizontal liquid velocity. Different operating conditions have been tested to show the impact of each parameter on hydraulics and aeration performance.The increase of air flow rate induces an increase of the local gas retention, of the gas velocity as well as of the Sauter diameter. Changes in these local parameters do exhibit a strong impact on the oxygen transfer coefficient. Hence these local measurements are used to discuss and gain a deeper understanding of the oxygen transfer phenomena.An augmentation of the horizontal liquid velocity results in higher values for the global oxygen transfer coefficient. This is confirmed by observation and local measurements, which show a stronger inclination of the air plume with increasing velocity. This translates to a larger course for the bubbles to cover before reaching the surface.With respect to global oxygen transfer measurements, the optimal position of the agitator was found to be near the bottom of the reactor for the type of pilot plant studied. In addition it can be stated that the horizontal position of the impeller has a large impact on the liquid horizontal velocity. Improved understanding is gained through local investigations, which reveal the increased inclination of the air plume as one major cause.     

Adhesive technology and sustainability

After considering problems associated with reconciling sustainability with a commitment to growth, the major environmental impacts of adhesive technology are discussed.Most adhesives come from fossil fuel sources, but many adhesive types can be produced from renewable resources either by traditional or newly developed routes. Significant energy usage in production and processing make energy conservation and renewable energy generation relevant to adhesive technology. Considerable improvements have been made by the replacement of volatile organic compounds in pretreatments and as solvents by aqueous systems, and more remains to be done.It is important to consider the total environmental impact of the engineering context in which the adhesive is to be used: adhesive technology may give improved engineering efficiency in the traditional sense of the term, and also lower environmental impact.     

工业烟气脱硫工艺进展

随着中国对环保的日益重视,SO2的排放浓度也受到严格限制。在中国一些地区,SO2排放浓度限值已要求≤20 mg/m3。因此,电厂、水泥厂等污染型企业必须采取有效措施以控制SO2的排放浓度。目前,脱硫技术主要分为干法脱硫、半干法脱硫以及湿法脱硫等。每种脱硫方法又包括多种工艺。此外,中海油天津化工研究设计院有限公司开发的组合式脱硫技术在水泥厂烟气脱硫方面有着良好的应用。该脱硫工艺具有使用条件宽、建设和运行费用低、脱硫率高的特点,可以实现二氧化硫的超低排放。且该脱硫工艺不会引入钾、钠、氯、硫、磷等有害元素,因而不会影响水泥熟料的生产过程。     

房地产建设项目环境影响评价中的污染防治措施

在房地产建设项目的环境影响评价工作中,往往对于污染防治措施的分析环节显得比较薄弱,或者不够重视。根据《环境影响评价技术导则》(HJ/T2.1-93)中的有关规定,环保措施建议一般包括污染消减措施建议和环境管理措施建议两部分,其中消减措施建议应尽量做到具体、可行,以便对建设项目的环境工程设计起指导作用。因此,在房地产建设项目环境影响评价中应该加强分析和论述污染防治措施,更好地为环境保护做好指导作用。     

Dynamics of the wet-end section in paper mills

A model representing the wet-end section of a paper mill has been developed to characterize its dynamic behavior during the grade change. The model is based on the mass balance relationships written for the simplified wetend white water network. From the linearization of the dynamic model, higher-order Laplace transfer functions were obtained followed by the reduction procedure to give simple lower-order models in the form of 1^st-order or 2^nd-order plus dead times. The dynamic response of the wet-end is influenced both by the white water volume and by the level of wire retention. Effects of key manipulated variables such as the thick stock flow rate, the ash flow rate and the retention aid flow rate on the major controlled variables were analyzed by numerical simulations. The simple dynamic model developed in the present study can be effectively used in the operation and control. This paper is dedicated to Professor Se Ki Moon on the occasion of his retirement from Hanyang University.     

乌鲁木齐市塑料垃圾年产量预测及影响因素分析

基于2008-2019年来乌鲁木齐市塑料垃圾在生活垃圾中的占比、生活垃圾清运量以及社会经济发展的相关数据,运用线性回归方程模型、ARIMA模型和灰色预测模型对乌鲁木齐市的塑料垃圾年产量进行预测,再用灰色关联度模型确定出主要的影响因素。结果表明,乌鲁木齐市塑料垃圾年产量呈线性增长趋势,由2008年的4.75×10⁴ t增长到2018年的35.14×10⁴ t;从单因素来看人均可支配收入对塑料垃圾产量的影响最大,总体来看城市人口对塑料垃圾产量影响最大,而环境建设水平则最小;通过对比,ARIMA模型是预测乌鲁木齐市塑料垃圾年产量的最优模型;预测结果表明预计到2025年、2035年和2050年乌鲁木齐市塑料垃圾年产量将分别达到54.4×10⁴、82.63×10⁴、124.91×10⁴ t。