湿法烟气脱硫系统GGH腐蚀和结垢对策研究

湿法烟气脱硫系统GGH的运行存在着腐蚀和结垢、堵塞的现象.分析了湿法脱硫系统GGH在运行过程中腐蚀、结垢的原因,从运行、维护等方面提出来减轻GGH腐蚀、结垢的策略.     

湿法烟气脱硫GGH换热元件结垢问题探讨

针对三河发电有限责任公司一期工程配套脱硫系统GGH换热元件结垢现象,分析了GGH换热元件结垢原因,提出减缓GGH结垢的措施,为相关脱硫项目运行提供参考。     

脱硫系统GGH吹灰器高压水喷嘴改进

GGH堵塞是脱硫系统运行常见问题之一,介绍了通过扩大吹灰器高压水喷嘴口径,增加喷嘴射流流量,提高对脱硫系统GGH清洗效果的途径,并实现脱硫系统不开烟气旁路挡板进行GGH波纹板高压清洗的目的。     

600MW机组脱硫GGH技改措施及节能优化

针对山西阳城电厂2×600 MW机组脱硫系统烟气换热器（简称GGH）在运行中频繁堵塞、差压大、增压风机运行电流偏大、影响机组带负荷及脱硫系统安全稳定性下降等问题进行了分析,提出了GGH改造方案及运行优化措施,确保了机组及脱硫系统的安全、稳定运行.     

湿法脱硫系统GGH堵塞原因分析及改进措施

通过对2×300MW机组脱硫系统GGH及除雾器堵塞原因的分析,认为烟气携带浆液是造成脱硫系统堵塞的主要原因。分别从烟气流量和影响系统通流面积的角度对烟气携带浆液造成系统堵塞的问题提出了改进措施,为设置GGH的脱硫系统避免GGH堵塞、确保系统长周期运行提供了良好的借鉴。     

GGH换热元件结垢堵塞原因分析及防治措施

京隆发电公司脱硫系统运行过程中经常发生GGH换热元件结垢和堵塞现象,分析了GGH结垢和堵塞的原因,主要包括除雾器除雾效率差;脱硫系统水平衡设计不合理;除雾器冲洗水系统故障、设计不当或冲洗不足;吸收塔补充石灰石浆液量过大;GGH换热元件波形板或GGH换热面高度设计不合理;吹灰系统设计不合理;氧化风量不足;吸收塔液位长时间保持在高液位、消泡剂添加不足;燃煤硫分的变化及吸收剂品质不好等。提出了防治措施,较好地解决了GGH换热元件结垢和堵塞的问题。     

燃煤电厂脱硫系统GGH堵塞的改造治理

GGH堵塞是燃煤电厂脱硫系统最常见、影响最严重的问题,解决该问题能促进脱硫系统安全、稳定运行.研究发现,更换换热元件以及改造冲洗系统能够有效地解决这个问题.实际应用表明,这不但解决了GGH堵塞问题,还带来了良好的经济效益.     

火电厂脱硫吸收塔临时烟囱的选型设计

为了解决不设置烟气加热设备（以下简称GGH）后电厂主烟囱防腐和烟道改造施工而影响机组正常运行这一难题,在脱硫塔顶部设置临时烟囱排放烟气。以安阳电厂烟气脱硫工程为实例,从工艺、环境影响、制造和施工安装等方面具体介绍了脱硫吸收塔临时烟囱的设计,为不设GGH的脱硫技改工程提供参考。     

热管式GGH在湿法烟气脱硫中的应用

在湿法脱硫中,通常需要对脱硫后的烟气再加热.对热管式烟气再热器（GGH）的技术特点进行了介绍,并与目前普遍采用的回转式GGH进行了比较,认为热管式GGH作为湿法脱硫的烟气再热装置是可行的.     

三河电厂脱硫系统GGH堵塞及治理

分析了国华三河发电厂一期2×350MW机组配套脱硫系统GGH堵塞的原因及对脱硫系统的影响,结合三河电厂生产实践,给出了解决措施,为石灰石—石膏湿法脱硫系统的运行提供参考。     

SERIAL BATCH TESTS PERFORMED ON MUNICIPAL SOLID WASTE INCINERATION BOTTOM ASH AND ELECTRIC ARC FURNACE SLAG,IN COMBINATION WITH COMPUTER MODELLING

To predict long-term behaviour of wastes, knowledge is needed about the mechanisms controlling the leaching. The serial batch leaching test, developed in this study, is a version of an ordinary column test that allows sampling at different places in the column. In this study the results from the experiment are compared with computer simulations made with the coupled geochemical and transport program CHEM- FRONTS. The experiments showed that some elements, for example potassium, are easily leached, while the leaching of others, for example iron, is slower. The leaching of some elements is solubility controlled whereas others are controlled by dissolution kinetics. The comparison between the experiments and the computer simulations shows good agreement for most elements. A flow through system has been simulated for the steel slag based on the results from the experiments and the computer simulation thereof. The latter simulation gives an idea of the long-term leaching behaviour of the steel slag. The conclusion of the work is that a combination of serial batch leaching test and computer simulation with a geochemical transport program can give good information about the long-term leaching of waste materials.     

Utilization of municipal solid waste incineration fly ash for sulfoaluminate cement clinker production

The feasibility of partially substituting raw materials with municipal solid waste incineration (MSWI) fly ash in sulfoaluminate cement (SAC) clinker production was investigated by X-ray diffraction (XRD), compressive strength and free expansion ratio testing. Three different leaching tests were used to assess the environmental impact of the produced material. Experimental results show that the replacement of MSWI fly ash could be taken up to 30% in the raw mixes. The good quality SAC clinkers are obtained by controlling the compositional parameters at alkalinity modulus (C(m)) around 1.05, alumina-sulfur ratio (P) around 2.5, alumina-silica ratio (N) around 2.0~3.0 and firing the raw mixes at 1250 °C for 2h. The compressive strengths of SAC are high in early age while that develop slowly in later age. Results also show that the expansive properties of SAC are strongly depended on the gypsum content. Leaching studies of toxic elements in the hydrated SAC-based system reveal that all the investigated elements are well bounded in the clinker minerals or immobilized by the hydration products. Although some limited positive results indicate that the SAC prepared from MSWI fly ash would present no immediate thread to the environment, the long-term toxicity leaching behavior needs to be further studied.     

Online elemental analysis of process gases with ICP-OES: A case study on waste wood combustion

A mobile sampling and measurement system for the analysis of gaseous and liquid samples in the field was developed. An inductively coupled plasma optical emission spectrometer (ICP-OES), which is built into a van, was used as detector. The analytical system was calibrated with liquid and/or gaseous standards. It was shown that identical mass flows of either gaseous or liquid standards resulted in identical ICP-OES signal intensities. In a field measurement campaign trace and minor elements in the raw flue gas of a waste wood combustor were monitored. Sampling was performed with a highly transport efficient liquid quench system, which allowed to observe temporal variations in the elemental process gas composition. After a change in feedstock an immediate change of the element concentrations in the flue gas was detected. A comparison of the average element concentrations during the combustion of the two feedstocks showed a high reproducibility for matrix elements that are expected to be present in similar concentrations. On the other hand elements that showed strong differences in their concentration in the feedstock were also represented by a higher concentration in the flue gas. Following the temporal variations of different elements revealed strong correlations between a number of elements, such as chlorine with sodium, potassium and zinc, as well as arsenic with lead, and calcium with strontium.     

Assessment of the leaching of metallic elements in the technology of solidification in aqueous solution

Results are presented of experiments performed to optimize the solidification/stabilization system for metallic elements in aqueous solution. This system involves mixing cement and a solution of metallic elements in a conventional mixer: the paste thus obtained is transferred drop by drop into a recipient filled with an aqueous solution of NaOH at 20% by weight, in which it solidifies immediately. The separate use of chloride solutions of Li+, Cr3+, Pb2+ and Zn2+ makes it possible to obtain granules displaying various levels of compressive strength. Three different inertization matrices were used in the experiments, the first consisting solely of Portland cement, the second of Portland cement and a superplasticizer additive, and the third of Portland cement partially replaced with silica-fume and superplasticizer. The results of the tests performed showed a very low level of leaching into the alkaline solidification solution for Cr3+, the quantity leached being under 2% as against higher levels for the other metallic elements. For all the considered elements, the best results were obtained by using silica-fume in the inertization matrix.     

GHS化学品危险性分类及其公示要素(下)

概述了全球化学品统一分类和标签制度（GHS）的产生背景、推行GHS的重要意义,介绍了GHS关于化学品危险性分类和公示要素的主要内容,评估了我国现行化学品危险性分类与GHS分类的差异点,并对我国全面实施GHS提出了若干对策建议。     

GHS化学品危险性分类及其公示要素(上)

概述了全球化学品统一分类和标签制度（GHS）的产生背景、推行GHS的重要意义,介绍了GHS关于化学品危险性分类和公示要素的主要内容,评估了我国现行化学品危险性分类与GHS分类的差异点,并对我国全面实施GHS提出了若干对策建议。     

Study of Pollution of the Plitvice Lakes by Water and Sediment Analyses

The process of eutrophication in form of intense plant growth has been observed in some lakes and water streams at the Plitvice Lakes National Park in central Croatia. Here we investigate whether this phenomenon is a consequence of anthropogenic pollution or due to naturally produced organic matter in the lakes. We applied chemical analysis of water at two springs and four lakes (nutrients, dissolved organic carbon (DOC), trace elements) and measurements of surface lake sediments (mineral and organic fraction analyses, trace elements) in four different lakes/five sites. The chemical composition of water does not indicate recent anthropogenic pollution of water because the concentrations of most trace elements are below detection limits. The concentrations of DOC and nutrients are slightly higher in the area of increased eutrophication-plant growth. Also the content of organic matter in the sediment is at the highest level in areas with highest C/N ratio indicating that the organic fraction of this sediment is mainly of terrestrial origin. There is no significant difference among the trace element concentration in the upper segment of all cores, deposited approximately during last 50 years when higher anthropogenic influence is expected due to development and touristic activity, and the lower part of the cores, corresponding to the period approximately 100–200 years before present. The content of trace elements and organic matter in sediments decreases from the uppermost lake downstream. According to our results there is no indication of recent anthropogenic pollution in water and sediment. Higher concentrations of DOC in water as well as phosphorus and some other elements in the lake sediment can be a consequence of input of natural organic matter to the lake water.     

Use of Pb blast furnace slag as a partial substitute for fine aggregate in cement mortar

The technical properties of cement mortars containing natural fine aggregate that is replaced by lead blast furnace slag at 25 and 35% level were assessed at fixed water-to-cement (W/C) ratio and at fixed flow table value. The leachabilities of some toxic elements from the cement mortars were also assessed to test the environmental suitability of the slag for use in preparation of cement mortar. At fixed W/C ratio, the strength of the mortar decreased with increase of the slag content. On the other hand, at fixed consistency, strength increased with increasing slag content in the mortar composition. The concentrations of some toxic elements in the leachates collected from the mortars containing slag were slightly higher than for the control mortar, but the concentrations in the leachates remained within the regulatory limits for recycling in construction applications. For most elements, leaching from a mortar containing 35% of slag was similar to that from a mortar containing 25% of slag. Therefore, 35% of natural sand can be beneficially replaced with Pb slag to produce cement mortar without affecting the mechanical and leaching properties studied in this work.     

炼油废水体系中超滤膜表面污染物的剖析

分别采用扫描电子显微镜和能量色散谱仪对炼油废水体系中超滤膜表面污染物进行了形貌观测和元素组分含量分析,并研究了炼油废水中Fe、Si和Al含量对超滤膜表面形态和污染物组成的影响.实验结果表明:超滤膜表面的主要污染物为Ca,Fe,Si,Al,Mg的化合物形成的凝胶,元素含量大小顺序为Fe＞ Ca＞ Si＞ Mg＞ Al;随...     

Vitrification of electric arc furnace dusts

Electric arc furnace baghouse dust (EAFD), a waste by-product of the steelmaking process, contains the elements that are volatilized from the charge during the melting (Cr, Pb, Zn, Cu and Cd). The results of leaching tests show that the concentration of these elements exceeds the regulatory limits. Consequently, EAFD cannot be disposed of in ordinary landfill sites without stabilization of the heavy metals. In this work, the vitrification of EAFD, from both carbon and stainless steel productions, were studied. The vitrification process was selected as the inertizing process because it permits the immobilization of the hazardous elements in the glass network and represents an environmentally acceptable method for the stabilization of this waste. Classes of various compositions were obtained by mixing EAFD with glass cullet and sand. The EAFD and the glass products were characterized by DTA, TG, X-ray analysis and by the TCLP test. The results show that the stability of the product is influenced by the glass structure, which mainly depends on the Si/O ratio. Secondary crystallization heat-treatment were carried out on some samples. The results highlighted the formation of spinel phases, which reduced the chemical durability in acid media. The possibility to recover Zn from carbon steel production EAFD was investigated and about 60-70% of metal recovery was obtained. The resulting glass show higher chemical stability than glasses obtained without metal recovery.