粉煤灰在水处理领域的应用进展

为了实现燃煤电厂粉煤灰资源化再利用于废水污水治理、为粉煤灰在污水治理方面的应用研究提供参考,结合粉煤灰的物理性质、化学组成及在水处理过程中的作用原理,分析了粉煤灰在处理生活污水、印染废水、重金属离子废水、含氟废水、造纸废水以及其他废水中的应用进展,结果表明:在适当条件下,粉煤灰对于废水中各种污染物的去除率均可达到57%以上,表明其用于水处理领域是可行的。提出了未来需解决的主要问题是通过改性提高粉煤灰的活性及二次污染的处理,这对于煤炭燃烧固体废物短流程资源化技术的进一步发展具有一定的指导意义。     

改性粉煤灰处理含磷废水的进展

粉煤灰是电厂发电后产生的废弃物,导致水体的富营养化重要原因之一是总磷量超标,用粉煤灰处理废水中含磷过多的问题,可达到以废治废的目的。本文对改性(热、酸、碱、盐)后粉煤灰在生活污水中吸附磷的研究成果进行总结,显示粉煤灰通过改性对磷具有较好的吸附性能,热改性粉煤灰在400℃时性价比最好,使用硫酸对粉煤灰进行改性后对磷的吸附效果最佳。通过对大量有关文献的分析,研究改性后的粉煤灰对废水中磷的吸附性能,并通过热、酸、碱、盐多种方式使粉煤灰进行改性,能够有效解决在生活废水中的含磷量过多的问题,具有广泛应用的前景。     

酸改性粉煤灰处理生活废水的研究

本研究用粉煤灰处理生活废水,得出在反应条件为:粉煤灰用量15 g,吸附时间25 min,反应温度30℃,pH为3时,废水中污染物去除效果最好。当粉煤灰用2 mol/L的硫酸改性后,废水的处理效果最理想,CODCr去除率达84%以上。用废制废,变废为宝的环保方法,是环保工作者值得采用的污染物处理手段。     

粉煤灰治理废水废气的机理及应用

介绍了粉煤灰的物理化学特性,并对利用粉煤灰处理废水废气的机理进行了分析,对粉煤灰在废水废气治理方面的应用作了介绍,并分析了粉煤灰在处理城市污水、印染废水、造纸废水中的应用工艺,以及改性粉煤灰处理废水的效果.粉煤灰处理废气的应用主要是烟气脱硫,对喷雾干燥脱硫工艺作了介绍和分析.     

粉煤灰改性方法及机理的研究进展

我国粉煤灰排放量大，严重污染环境。鉴于粉煤灰的化学吸附和物理吸附双重特性，利用粉煤灰处理氨氮废水可以达到以废治废目的。目前粉煤灰对氨氮废水的吸附量较低，因此通过粉煤灰改性提高对氨氮废水的吸附量具有重要意义。本文概述了粉煤灰的应用现状及改性粉煤灰对氨氮废水吸附性能研究进展，粉煤灰改性可以破坏粉煤灰网状结构，断裂其Si-O、Al-O键，激发活性组分Al₂O₃和SiO₂,提高粉煤灰的比表面积和孔道数量，利于对氨氮废水吸附。     

改性粉煤灰对水中硫化物吸附性能研究

用粉煤灰经氢氧化钠改性后吸附水中硫化物,研究了改性后的粉煤灰在不同温度、粒度、用量、时间下对硫化物的吸附差异性,同时用改性后粉煤灰在最佳的吸附条件下处理了生活废水,吸附效果较好。     

改性粉煤灰处理含苯胺废水的研究

文章对十六烷基三甲基溴化铵(CTAB)改性粉煤灰处理含苯胺废水进行了研究。通过实验考察了吸附时间、改性粉煤灰粒度、吸附温度、废水的pH和改性粉煤灰加入量对废水中苯胺去除率的影响。实验结果表明,改性粉煤灰处理含苯胺废水的最佳处理条件为:吸附时间为30 min、改性粉煤灰粒度为120~140目、吸附温度为25℃、废水的pH为3.0、改性粉煤灰加入量为6 g。在此条件下可使50 mL模拟含苯胺废水中苯胺的浓度由500 mg/mL降至15.03 mg/mL,苯胺的去除率达97%。利用改性粉煤灰处理含苯胺废水不仅处理效果好而且达到了以废治废的目的。     

改性粉煤灰处理印染废水的研究

主要对改性粉煤灰处理印染废水进行了研究。通过实验考察了吸附时间、吸附温度、改性粉煤灰加入、改性粉煤灰粒度和废水的pH对废水中色度去除率的影响。实验结果表明,改性粉煤灰处理印染废水的其最佳工艺条件为:吸附时间为70min、吸附温度为30℃、改性粉煤灰加入量为2.4g、改性粉煤灰粒度为100～120目、废水pH为10.0。在此条件下可使100 mL模拟印染废水中色度由600倍降到65倍,色度去除率达89.2%,达到了国家《污水综合排放标准》二级标准。     

粉煤灰对苯胺废水的吸附研究

在静态条件下研究了粉煤灰对含苯胺废水的处理。比较了不同条件下粉煤灰对苯胺废水的处理效果,确定了处理废水时间、粉煤灰用量、废水pH值、温度、废水中苯胺浓度对处理结果的影响。结果表明,粉煤灰在时间30min、用量8.0g、温度25℃、pH值2.5左右时,对100ml浓度为200mg/L的含苯胺废水的吸附效果最好,去除率高达97.7%。处理后的苯胺废水达到国家三级排放标准(5.0mg/L)。     

改性粉煤灰对活性艳红溶液脱色处理研究

粉煤灰是煤炭燃烧后的废弃物,比表面积较大,对染料大分子具有一定的吸附脱色能力。文章以活性艳红染料模拟废水为研究对象,考察酸性粉煤灰和碱性粉煤灰对染料废水的吸附脱色作用,结果表明碱性粉煤灰对活性艳红模拟废水吸附脱色效果较好。同时分别考察了氢氧化钙质量比、粉煤灰活化温度、粉煤灰的加灰量、废水pH及初始浓度对吸附活性均有影响。当粉煤灰与氢氧化钙质量比为3.0、活化温度为300℃、粉煤灰加入量为5 g/L时,pH为10.0、浓度为20 mg/L的染料溶液脱色率可达99.2%。     

粉煤灰吸附处理含铬废水的试验研究

利用经2 mol/L的硫酸改性的粉煤灰,来研究粉煤灰吸附处理实验室模拟含铬废水。实验结果表明：处理100 mL含六价铬浓度为50 mg/L的废水,调节pH值2～3,投加8 g改性粉煤灰,反应80 min后六价铬的去除率达到90%以上;吸附符合Freundlich等温吸附式。利用粉煤灰吸附处理含铬废水,具有处理效果好,操作简单,运行费用低等优点,因此,粉煤灰可以作为一种有效的吸附剂来处理含铬废水。     

粉煤灰在含氟含磷废水处理中的应用

粉煤灰是火电厂排出的固体废弃物,其作为絮凝剂和吸附剂在废水处理方面已经得到了广泛的应用。人体长期过量摄入氟元素会导致地方性氟病,磷是引起水体富营养化的限制因素。该文叙述了粉煤灰在含氟含磷废水中的应用现状,探讨其影响因素和改性方法,并进一步分析了粉煤灰除氟除磷的机理。结果表明,粉煤灰的组成,特别是其Ca/CaO含量和反应的操作条件对氟、磷的去除效果有较大的影响;酸、碱、盐、微波、负载、工艺改变和新材料转化等改性方法有利于提高粉煤灰对氟和磷的处理能力;粉煤灰对氟和磷的去除主要依赖于吸附作用和凝聚作用。     

粉煤灰的综合利用

粉煤灰是煤粉经高温燃烧后形成的一种似火山灰质混合材料。广义的粉煤灰包括飞灰和炉渣。中国1995年粉煤灰排放量达1.25亿t,2000年约为1.5亿t,2009年粉煤灰排放量约3.75亿t。如何使用好累积下来的二次能源,减少占地面积,减少环境污染,创造更高附加值,综合利用粉煤灰越来越受到人们的关注。介绍了粉煤灰的物化性质和在建筑、建材工业、农业、化学工业等方面的综合利用,对粉煤灰的发展趋势提出了建议,注重精细化、高效益的粉煤灰利用。     

间苯二酚废水处理工艺研究

对间苯二胺高温高压水解法制备间苯二酚的废水的处理方法,从有机物去除率、副产硫酸铵质量等方面,比较了不同吸附工艺的处理效果。确定了氨中和、粉煤灰吸附、树脂吸附、浓缩、结晶、分离、干燥的废水治理工艺流程。经本工艺处理后,废水中的无机盐成为农用肥料,回收水和有机物得到循环利用。     

Combustion of a fuel mixture in a high-temperature cyclone reactor

The results of an experimental study of the combustion of pulverized fuel mixtures in a high-temperature cyclone reactor, a new type of furnace device, are presented. The temperature profiles in the reactor and the composition of the ash residue are shown. Thermograms of the thermolysis of pulverized coal and sawdust, as well as mixtures thereof, are displayed. It was demonstrated that in contrast to the combustion of pulverized coal alone, the combustion of a coal-sawdust mixture yields not only fine ash, but also slag.     

Pozzolanic activity of pulverized fuel ash

The pozzolanic activity of pulverized fuel ash (p.f.a.) has been determined by measuring the rate of dissolution of silica from p.f.a. in 0.1 M hydrofluoric acid. The rate of extraction of silica follows a logarithmic law and the rate constant is an index of the pozzolanic activity of the ash.     

高效煤粉锅炉粉煤灰在熟料生产中的应用

山东东华水泥有限公司目前有两条5 000 t/d熟料生产线, 处理我市高效环保煤粉锅炉的产生的粉煤灰。通过增加高效煤粉锅炉粉煤灰的储存、计量和输送设备,实现了高效煤粉锅炉粉煤灰计量可控的掺加到生料中,并随生料一起进入回转窑煅烧的工艺途径,成功地解决了高效煤粉锅炉粉煤灰因成分波动大、烧失量高导致的水泥磨消耗量有限的处置瓶颈。     

Ash formation during pulverized coal combustion : 1: Aerodynamic influences

The elemental composition of pulverized fuel boiler deposits often differs markedly from that of the corresponding fly ash and coal ash. Evidence is given here to support the hypothesis that such chemical segregation could be induced by competition between aerodynamic drag and inertial forces on a particle in a curved streamline; this increases the probability of impacting the boiler walls for large particles of high density, leading to preferential deposition. A conventional air classifier was used to separate mono-sized samples of pulverized coal and char particles into aerodynamically different fractions, and to prepare vitrinite-char and inertinite-char concentrates. The relevance of such aerodynamic segregation is considered by comparing the enrichment (or depletion) of non-volatile elements in boiler ashes with that in ashes derived from air-classified char fractions. Common trends, particularly for iron (the major fluxing element) have been identified (i) between the highest density fractions and furnace deposits, and (ii) between the lower density fractions and cyclone ash.     

Ash behaviour in a pulverized wood fired boiler—a case study

The behaviour of the mineral matter in a fuel may crucially affect the availability of a boiler when the fuel is fired. The ash may cause severe problems in the flue gas channel in forms of fireside deposits on heat exchangers. These deposits lower the efficiency of the boiler and cause in the most severe cases an unscheduled shutdown.In this paper we report results from a study where the ash behaviour was monitored in a pulverized wood fired boiler. Short-term deposit sampling was combined with in situ fly ash and flue gas sampling as well as advanced fuel analyses.By combining these three tools we could track down a chain of events the ash went through from the point where it was introduced into the boiler with the fuel until the stage where it formed a deposit on a heat exchanger tube.Sub-micron sized ash particles found in the flue gas with a Berner-type low-pressure impactor were enriched in alkali, sulphur and chlorine. Similar particles were also found on the backside of the air-cooled deposit sampling probes, forming thin initial alkali, sulphur and chlorine-rich deposit layer. These elements were further found by advanced fuel analysis to be associated with the moisture or the organic phase of the fuel.Larger ash particles of the size of 1-10 μm found in the flue gas with the low-pressure impactor were found to deposit on the front side of the sampling probe. These particles consisted mainly of calcium, most likely oxide or carbonate. With the advanced fuel analyses we could find these particles already as mineral particles in the wood fuel.We also saw some indication that peat could act as a cleaning fuel. In general the results show that a detailed well-performed fuel analysis is a key knowledge when ash behaviour predictions are to be made.     

改性粉煤灰的制备及性能研究

在高钙粉煤灰中加入强碱液制备了改性粉煤灰,测定结果表明,改性后粉煤灰的堆积密度、比表面积、颗粒形貌等明显优于改性前。改性后粉煤灰的孔隙发达,吸附性能显著提高,对废水中Pb~(2 )的去除率达99.99%。同时对金属阳离子具有很强的吸附能力,可在吸附酸性气体及处理酸性废水等方面进一步探索。