石灰石及盐类混合物在粉粒喷动床内的半干湿法脱硫

开发一种新型粉粒喷动床半干湿法脱硫过程。在这个过程中，喷动床为一个多相反应器。在喷动床中，二氧化硫与脱硫剂反应，脱除烟道气中的二氧化硫。实验采用石灰石作为脱硫剂，并考察操作条件对脱硫效率的影响。结果表明，脱硫效率受到几个因素的影响：钙硫比、饱和接近度、脱硫剂直径、粗粒子的静床层高度以及气体的表观流速。当石灰石粒径小于5μm、钙硫比大于1．5、饱和接近度为6℃时，脱硫效率可高于90％，而脱硫剂利用率超过60％。一些碱金属化合物可被用作提高脱硫效率和脱硫剂利用率的添加剂。实验结果表明：在喷动床烟道气脱硫过程中，添加氯化钠可显著提高脱硫效率。而且在脱硫浆料中，氯化钠与石灰石之比小于0．2时，脱硫效率随氯化钠浓度增加而增加。这个研究结果表明利用海水制备脱硫浆料成为可能。     

石灰石在粉粒喷动床内的半干湿法烟气脱硫

以石灰石为脱硫剂在粉粒喷动床内的半干湿法烟气脱硫是一种新的烟气脱硫过程。本文研究了操作条件对烟气脱硫效率的影响。结果表明,随着Ca/S的增加、饱和接近度及石灰石粉体直径的减小,烟气脱硫的效率提高。考虑到石灰石较之消石灰作为脱硫剂在价格和来源上的优势及本烟气脱硫过程所取得的较高效率,以石灰石为脱硫剂在粉粒喷动床的半干湿法烟气脱硫是一种可提供的烟气脱硫过程。     

Comparisons of Fly Ash and Deposition Between Air and Oxy-FuelCombustion in Bench-Scale Fluidized Bed with Limestone Addition

In Oxy-fuel circulating fluidized bed, the residual CaO particles may react with high concentration of CO₂ in flue gas to form bonded deposit on heat transfer surfaces in backpass when limestone is used as a sorbent to capture SO₂.In this paper, experiments were designed on ash deposition in a bench-scale fluidized bed under oxy-fuel and air atmosphere. A novel ash deposit sampling probe was used to simulate the tubes of tail surfaces. The chemical composition of fly ash and ash deposit from both air-firing and oxy-fuel firing cases were analyzed by Inductively Coupled Plasma-Atomic Emission Spectrometry(ICP-AES) and Scanning Electron Microscopy(SEM), respectively. The degrees of carbonation reaction of ash deposits were measured by Thermo Gravimetric Analysis. The results showed that there are distinct differences in fly ash deposition rate between oxy-fuel and air firing cases, and oxy-fuel combustion with limestone addition can affect chemical composition of fly ash and ash deposit, especially for elements of Ca, Na, K, and S. However, the carbonation reaction degree of ash deposits is found weak, which is due to the relatively low CaO content in ash deposit or not long enough of the sampling time.[JP]     

Properties and mechanism of CFBC fly ash-cement based stabilizers for lake sludge

Circulating fluidized bed combustion(CFBC) fly ash was mixed with cement or lime at a different ratio as a stabilizer to stabilize lake sludge.In order to understand the influences of stabilizers on the lake sludge properties,tests unconfined compressive strength,water stability and SEM observation were performed.The experimental results show that with the increase of the curing time,the strength of all the stabilized specimens increase,especially the samples containing cement.The strength of the specimens is decreased with the increasing of the CFBC fly ash/cement ratio,the optimum ratio between CFBC fly ash and cement is 2:3.The water stability of CFBC fly ash-cement based stabilizers is higher than those of cement and lime.Moreover,the lake sludge stabilization mechanism of CFBC fly ash-cement based stabilizers includes gelation and filling of the hydration products,i e,C-S-H gel and the AFt crystal,which act as benders to solidify those particles together and fill in the packing void of the aggregates.     

粉煤灰脱除烟道气SO2实验

以粉煤灰作为脱硫剂，采用固定床反应器，以模拟烟道气对粉煤灰的脱硫性能进行了研究，结果表明，在粉煤灰加入量为120g、含水率20％左右，对烟气流量为4L／min、SO2浓度为0．2％(体积浓度)的模拟烟道气脱硫效率可达最佳水平，脱硫率维持98％的时间可达到6min．粉煤灰对低浓度的二氧化硫脱硫效果较好，即比较适合用于锅炉烟道气脱硫．     

脱硫石膏－粉煤灰活性掺合料设计及水化特性

针对电厂两大工业废渣--烟气脱硫石膏及粉煤灰,通过试验研发用于混凝土的活性复合矿物掺合料.以适当比例复合后的脱硫石膏及粉煤灰等量取代水泥掺入到水泥砂浆中,通过活性激发措施,以胶砂流动度、早期强度以及强度发展规律等作为控制指标探索脱硫石膏及粉煤灰的最优配比,同时通过微细观结构的SEM观测评价脱硫石膏-粉煤灰活性矿物掺合料在水泥基材料中的作用效应.结果表明,脱硫石膏及粉煤灰以1:2的比例复合等量取代水泥30%掺入水泥砂浆中,可获得较为优异的胶砂流动度、早期强度,而后期强度能赶上甚至超过基准水泥胶砂;SEM表明由于脱硫石膏及其它外加组分的活性激发效应,粉煤灰的活性得到有效激发,早期有明显的钙矾石生成.脱硫石膏-粉煤灰复合矿物掺合料的研发可大量消纳燃煤电厂的工业废渣,且在水泥基材料体系中具有优异的水化及低成本特性,具有显著的"绿色"效应,符合中国"可持续发展"的战略要求.     

粉煤灰性质比较研究及综合利用途径探讨

目的为更有效利用不同性质的粉煤灰．方法采用水泥性质实验、化学分析、XRD分析及SEM分析．结果化学成分差异不大的PF灰和AFBC灰，PF灰的细度大、晶相含量小、活性大、强度贡献大、需水性小；PF灰颗粒细小，球形颗粒相对较多，颗粒表面相对较光滑；AFBC灰颗粒相对较粗大，不规则颗粒较多，表面较粗糙，且孔洞较多．提出了一种新粉煤灰的分类方法和高效利用途径．结论将粉煤灰按发电方式及含钙量分为高钙PF灰、低钙PF灰、高钙AF—BC灰和低钙AFBC灰，更有利于粉煤灰在建筑工程和生产建筑材料方面的分类利用．     

燃水煤浆飞灰的电除尘特性分析

为了提供水煤浆燃后烟气电除尘净化的设计依据，评述了水煤浆的燃烧方式及特点；对普通水煤浆飞灰的形态、化学成分、粒度分布、比电阻及驱进速度等电除尘特性做了定性和定量分析，并与燃煤飞灰的分析结果做了对比，结果表明，水煤浆飞灰不是高比电阻粉尘；燃水煤浆飞灰粒度分布、比电阻、驱进速度等电除尘特性优于燃煤飞灰。     

我国燃煤污染控制技术与对策的研究

煤的燃烧是造成我国大气污染的最大污染源，烟气脱硫是使S02减排量最大和最有效的措施，但是代价昂贵。为使环保投入能够产生明显的社会效益和经济效益，中日合作研究与开发了适合发展中国家的新型的烟气脱硫技术，这是我国SO2污染防治基础研究及技术发展的主要方向。本文介绍了几种烟气脱硫新技术和我国自行开发的低NOx煤粉燃烧技术、减少可吸入颗粒物排放的技术、利用烟气脱硫副产物的技术。     

Influence of fly ash fineness and shape on the porosity and permeability of blended cement pastes

The effects of the fineness and shape of fly ash on the porosity and air permeability of cement pastes were investigated. Pulverized coal combustion (PCC) fly ash and fluidized bed coal combustion (FBC) fly ash classified into three different finenesses were used. River sand with particle size distribution similar to that of fly ash was also used for comparison. Portland cement was replaced with fly ash and ground sand at the dosages of 0, 20wt%, and 40wt%. A water-to-binder ratio (w/b) of 0.35 was used thr...     

THE INFLUENCE OF TEMPERATURE AND ADMIX- TURES ON ACTIVATION OF LOW CALCIUM FLY ASH

According to composition and structure properties of low calcium fly ash, the activation and reaction degree of fly ash—lime and fly ash—lime—gypsum system were studied in different alkali surroundings and temperatures by thermal-gravity analysis. The degree of reaction and pore structure analysis test results show that composite alkali play an important role in the activation and degree of reaction of fly ash at room temperature. But when increasing curing temperature, gypsum would play an important role in activation and hydration of fly ash.     

Utilization of thermally treated flue gas desulfurization (FGD) gypsum and class-C Fly Ash (CFA) to prepare CFA-based geopolymer

The feasibility of utilization of flue gas desulfurization (FGD) gypsum and Class-C fly ash (CFA) to prepare CFA-based geopolymer were studied. The results showed that geopolymer made from 90% CFA and 10% FGD gypsum (FGDG) which was thermally treated at 800 ℃ for 1 h obtained the better compressive strength of 37.0 MPa. The micro characteristics and structures of the geopolymer samples of CFA and CFA-FGDG were tested by XRD, FT-IR, and SEM-EDXA after these samples cured at 75 ℃ for 8 h followed by 23 ℃ for 28 d. Both the geopolymer samples of CFA and CFA-FGDG have significant asymmetric stretching of Al-O/Si-O bonds and Si-O-Si / Si-O-Al bending band. In geopolymer sample of CFA-FGDG, a small quantity of lathy products probably being the ettringite wrapped over the spherical fly ash particle, and the concentration of sulfur is much more than that in geopolymer sample of CFA. It is indicated that FGD gypsum may react during alkali-activated and geopolymeric process.     

100MW燃煤电站汞排放及其形态分布

采用安大略法、汞连续测量仪和汞吸附法测量了多种烟气中的汞含量,分析了FGD,锅炉负荷和烟气特性对汞排放和形态分布的影响,计算了汞在燃烧产物中的分布及质量平衡.结果表明,这3种汞测试法的测量结果具有很好的一致性,其相对偏差小于20%,总汞的排放量随着锅炉负荷和煤中汞含量的变化而变化.     

不同改良剂对不同含砂率粉土改良性质研究

通过人工室内配制不同含砂率(10%、20%、40%)粉土,对其进行改良试验,研究在不同改良剂(石灰+水玻璃、石灰+粉煤灰)、不同配比作用下3种含砂率粉土的改良效果,研究结果表明:随着含砂率的增加,无论是素土还是改良土,其最大干密度均增大;对于石灰+水玻璃改良土,其最大干密度较素土有明显的降低,而石灰+粉煤灰改良土与之相反;石灰+水玻璃改良土最优含水率与素土略有差别,而石灰+粉煤灰改良土与素土最优含水率基本一致;在同一含砂率下,对于不同配比的石灰+水玻璃改良土,其最大压实度和最优含水率并未发生较大变化,10%石灰+20%粉煤灰的压实度高于其他配比情况;在恒定压实度(95%)下,改良土的无侧限抗压强度明显高于素土的无侧限抗压强度,改良剂对粉土起到一定的"维稳"效果,改良剂掺量才是决定无侧限抗压强度的关键因素。     

新型燃煤烟气汞吸附剂的评价研究

利用汞蒸气发生器产生的单质汞,与压缩空气组成模拟烟气,在吸附剂评价实验台上进行吸附剂脱汞实验,研究不同吸附剂对单质汞的脱除效率．实验结果表明,活性炭对汞的吸附效率在60％左右,未改性的燃煤飞灰吸附效率在10％～20％,改性后的燃煤飞灰比表面积有很大程度的提高,吸附效率可以达到25％,与活性炭吸附效率相比仍有不小的差距．     

循环流化床粉煤灰加气混凝土制备研究

利用X射线荧光光谱仪、XRD等检测手段对循环流化床粉煤灰进行化学成分定性和定量分析,然后确定配合比:粉煤灰65%,水泥12%,石灰20%,石膏3%。主要研究了在蒸压养护条件下,不同水料比、不同铝粉添加量、不同无机外加剂硫酸钠、氯化钙添加量对加气混凝土砌块容重和强度的影响,研究发现最佳水料比为0.65,最佳铝粉掺量为0.1%,无机外加剂硫酸钠对加气混凝土砌块的容重和强度影响不大,而添加0.25%的氯化钙比无外加剂条件下强度提高了40%,达到4.55MPa,且容重为910kg/m3,随着氯化钙量的增加,强度反而下降。     

石灰、粉煤灰改性对盐渍土吸附石油污染物行为的影响

有效调控污染物的运移是实现污染土工程再利用的前提。考虑石油污染盐渍土的特殊性及工程利用的力学需求,优选石灰和粉煤灰为改性材料,结合静态动态试验,研究石灰和粉煤灰对滨海盐渍土中石油污染物的吸附解吸行为的影响。结果表明：单独的石灰和粉煤灰,对石油污染物的吸附率分别为26%和14%,两者联合作用时,吸附率提高到39%,在盐渍土中加入石灰和粉煤灰可有效提高对石油污染物的吸附量,加快吸附稳定速率;盐渍土、石灰+盐渍土、粉煤灰+盐渍土、石灰+粉煤灰+盐渍土对石油的吸附动力学均符合Lagergren二级动力学非线性方程,联合作用可使吸附平衡时间由400 min缩短至60 min;石灰、粉煤灰有利于吸附赋存于土颗粒孔隙中未被盐渍土颗粒吸附的呈自由态的石油;盐渍土、石灰+盐渍土、粉煤灰+盐渍土、石灰+粉煤灰+盐渍土对石油污染物的吸附等温线均为非线性Freundlich模式;石油被解吸的能力依次为盐渍土 > 粉煤灰+盐渍土 > 石灰+盐渍土 > 石灰+粉煤灰+盐渍土,石灰+粉煤灰对石油污染物的吸附以化学吸附为主,具有不可逆性,有助于缓解环境温度的影响,增强稳定性。     

增钙灰的粉煤灰效应分析

本文从定性、定量两方面分析了增钙灰的“粉煤灰效应”．研究表明,品质好的增钙灰具有明显的“粉煤灰效应”,可用做掺合料配制较高强度的混凝土,“粉煤灰效应”包含形态效应、活性效应、微集料效应三方面的综合作周,定量分析便于把握材料的性质,指导材料的应用。     

工业重金属污泥的稳定化试验

以危险废物工业重金属污泥为研究对象,进行了水泥、石灰和石灰 粉煤灰3种稳定化工艺对重金属铅、镉、铬、铜、锌、镍浸出毒性的影响试验,结果表明,水泥稳定化工艺水泥添加量8%、石灰稳定化工艺石灰添加量2%、石灰 粉煤灰稳定化工艺添加量为10%石灰 10%粉煤灰时,均可满足《危险废物填埋污染控制标准》(GB 18598-2001)中关于"危险废物允许进入填埋区的控制限值"的要求.石灰稳定化工艺要求稳定剂的添加量相对较小,是该类工业污泥稳定化处理的理想稳定剂.     

Stabilization of Expansive Soil by Lime and Fly Ash

An experimental program was undertaken to sudy the individual and admixed efects of lime and fly ash on the getechnical charateristics of expansive soil .Lime and fly ash were added to the expansive soil at 4%-6% and 40%-50% by dry weight of soil respectively ,Testing specimens were detemined and examat 4%-65 and 40%-50％ by dry weight of soil ,respectively ,Testing specimens were detemined and examined in chemical composition .grain size distrbution ,consistency limits,compaction ,CBR,free suell and suell capacity ,The effect of lime and fly ash addition on reducing the swelling potenial of an expansive soil is presented.It is revealed that a change of expansive soil texture takes place when lime and fly ash are mixed with expanive soil .Plastic limit increases by mixing lime and liquid limit decreases by mixing fly ash ,which deceases plasticity index,As the amount of lime and fly ash is increased ,there are an apparent reduction in maximum dry density ,free swell and swelling capacity under 50 kPa pressure ,and a corresponding increase in the percethage of coarse particles,optimum moisture content and CBR value.Based on the results,it can be conculded that the expansive soil can be successfully stabilized by lime and fly ash.