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通过直流等离子体电弧熔融技术对危废焚烧灰渣熔融固化的处理效果的实验室研究,着重研究了其添加剂用量和熔融温度对灰渣中重金属固化效果和重金属的毒性浸出特性的影响,并对飞灰、底渣和熔渣的化学组成、物相组成、重金属毒性浸出特性和微观结构等进行了深入分析。结果表明,随着添加剂用量增加,熔渣中重金属固化率提高,重金属浸出质量浓度显著降低。熔融温度从1 250℃升高到1 450℃,重金属Cr、Ni、Cu、Zn的固化率显著提高,Pb、As的固化率逐渐降低。等离子体熔融产出的熔渣重金属浸出质量浓度都远低于毒性标准限值。本试验对于灰渣等离子熔融机理进行了深入研究,试验出最佳运行工况,对灰渣等离子技术装备的工业化开发具有重要意义。 相似文献
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为等离子技术装备开发提供具有工程应用价值的数据,采用中试规模的直流等离子体炉对危废焚烧灰渣进行高温熔融处理,考察了开弧、埋弧等对熔融特性的影响,研究了熔渣的组成、微观结构、重金属浸出特性及二次飞灰的特性和产生机理,并测算了熔融处理单位质量灰渣的能耗。结果表明,埋弧和开弧操作对熔渣的成分和晶体结构影响不大。但是,与开弧相比,埋弧操作利用了电阻、电弧加热熔渣,提高热效率,熔融单位质量灰渣的能耗为0.709 k W·h/kg。熔渣中的重金属浸出质量浓度远低于国家标准限值;二次飞灰的产率为7.5%,其主要成分为NaCl。 相似文献
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电力工业的迅速发展,使电厂灰渣排放量剧增,灰渣即时的综合利用仅一小部分,大部分灰渣贮存亟待解决。以调剂综合利用量,改善贮灰场对环境的污染,节约土地及水资源,降低基建投资的新的贮灰方式──干灰调湿碾压贮灰技术正得到发展。本文即对干灰碾压贮灰场设计与运行管理中部分关键问题进行探讨。 相似文献
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稠油污水处理场的初沉池中,通常产生大量的高含水污泥,其主要是由原油、泥砂颗粒、水及少量化学药剂和部分工业杂质形成的混合物.稠油油泥成分复杂、处理难度大.对稠油油泥进行脱水并掺混一定比例的煤作为燃料,是一种有效的稠油油泥资源化利用和无害化处理方式.利用自制实验装置进行实验,考察了油泥、原煤掺混比例对燃烧烟气污染物和灰分中重金属含量的影响.结果表明:油泥与原煤按1∶3的掺混比例燃烧时的效果最佳,烟气中主要的污染物NOx、SO2以及CxHy平均含量为147 μL/L 、420μ L/L以及106μL/L,均符合国家排放标准;重金属Pb、Hg、Cr和非金属污染物As在稠油油泥燃烧后的灰分中的平均含量分别为2.75mg/kg、0.05mg/kg、91.5mg/kg和0.68mg/kg,也都符合国家排放标准. 相似文献
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This study examined the effects of variations in alkali and alkaline earth metal content, bed material diameter, static bed height and gas velocity in a fluidized-bed combustion process to understand the distribution of heavy metals in bottom ash after agglomeration/defluidization. A smaller diameter bed material increased the relative abundance of small particle sizes in the bottom ash due to attrition and thermal impact at high temperature. The addition of Na led to an increase in the large particle abundance of the bottom ash, likely due to the formation of a eutectic with a low melting point, causing agglomeration. The addition of Ca inhibited the agglomeration/defluidization and increased the abundance of large particles in the bottom ash.In general, heavy metal concentrations increased when the bottom ash size was smaller than 0.59 mm and larger than 0.84 mm. Regarding the different fluidization parameters, the bottom ash had the lowest concentration of heavy metals at 1.5 Umf, an H/D of 2.1 and a bed material (silica) particle size of 0.645 mm. The concentrations of heavy metals in the bottom ash after Ca addition were higher than of those without Na or with Na only. Addition of Ca prolonged the operation time of fluidization and increased the feed quantity of heavy metal, helping the bed material adsorb more heavy metal. Therefore, the addition of Ca not only prolonged the fluidization time, reducing agglomeration/defluidization, but also resulted in a higher adsorption of heavy metals by the bed material, reducing their emission. 相似文献
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Effect of wood fly ash and compost on nitrification and denitrification in agricultural soil 总被引:1,自引:0,他引:1
Wood ash from biofuel combustion plants and compost from source-separated household waste are commonly spread on forest, agricultural and horticultural soils as a valuable source of plant nutrients. However, due to anthropogenic activities, wood ash may contain high concentrations of heavy metals. Heavy metals are toxic to microorganisms and therefore, soil microbial response to wood ash should be considered when soil is amended with ash. Compost is known to improve soil structure and may also act as a bioremediating agent, mitigating any toxic effects of wood ash on soil microorganisms. In the present study, the aim was to investigate whether wood ash has any toxic effect on soil microbial activity and, if this is the case, whether compost could mitigate these effects. The effect of wood fly ash on potential ammonium oxidation rate (PAO) and potential denitrification rate (PDA) in arable soil was investigated in one dose–response assay and in two pot experiments with or without plants, respectively. The treatments were amendment with wood fly ash, compost or a combination of wood fly ash and compost. PAO and PDA were assessed immediately or after 7 and 90 days in the different experiments. Wood fly ash decreased PDA to 16–56% compared to the control, while PAO varied between 82% and 205%. Sole compost addition stimulated both processes. This positive effect was also observed in the combined wood fly ash–compost treatment. In conclusion, wood ash had a toxic effect on PDA, both on an immediate, short-term and long-term basis. Amendment of compost clearly mitigated this toxic effect. The observed toxicity could be an effect of the metal content of ash. 相似文献
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目前生物质工业锅炉多采用层燃方式,生物质燃料灰熔点较低,灰成分碱金属含量高,结渣、受热面积灰、腐蚀等情况比较严重,制约层燃生物质锅炉的发展。另外在工业锅炉占很大份额的燃煤层燃炉炉渣含碳量普遍高于20%,造成能源浪费。本文根据生物质燃料以及层燃炉渣的特点,提出燃用生物质与层燃炉渣混合燃料循环流化床锅炉的设计构想。通过合理的燃料配比提高生物质燃料灰熔点,稳定流化床循环物料,采取一定措施减少碱金属的升华和尾部受热面积灰、腐蚀。并对其在小型工业锅炉应用的"节能减排"效果进行了预测。 相似文献
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采用Z-8200型原子吸收分光光度计和VF-320型X射线荧光光谱仪,定量测定了1台220t/h煤粉炉中原煤、底渣、飞灰中8种痕量元素的含量。基于改进的Meij相对富集系数,从底渣和飞灰两个方面,系统分析了温度、含氧量、飞灰粒径、痕量元素自身性质以及煤种特性迁移规律的影响。研究结果表明:炉膛温度升高能加快部分痕量元素的挥发;Cr和Mn在飞灰、废渣中含量相当,但两者相对富集系数明显不同;含氧量低并非促进所有痕量元素挥发;Pb、Cd、Zn、Cr在底渣和飞灰中含量并不一定都与各自的沸点成单一的关系;飞灰粒径越小,痕量元素富集系数越大,各痕量元素随飞灰粒径减小的变化趋势并不相同等。 相似文献
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煤飞灰中砷的形态特性 总被引:3,自引:0,他引:3
对某 3 0 0MW燃煤电厂锅炉进行煤、渣、飞灰取样后 ,测定煤和燃烧产物中砷的含量 ,计算了砷在燃烧产物中的分布 ,研究了电除尘 4个电场飞灰中砷含量与粒径的关系 .结果表明 ,通过除尘装置滞留下来的砷量占总砷量的 5 1.8% .飞灰中砷的含量随着粒度的降低而升高 .使用逐级化学浸提法研究了粒度不同的飞灰中砷的形态分布 .将飞灰中的砷分为水可浸出态、可交换态、碳酸盐 表面氧化物结合态、铁锰氧化物结合态以及残渣态 .不同粒径的飞灰形态分布相似 ,即残渣态 >碳酸盐 表面氧化物结合态 >铁锰氧化物结合态 >可交换态 相似文献
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Aleksandar Popovic Jasna Djinovic 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2013,35(13):1189-1201
The content of selected trace and major elements in the river water used for transport, as well as in the subcategories of the waste waters (overflow and drainage) were analyzed in order to establish the influence of transport and dumping of coal ash and slag from the “Kostolac A” and “Kostolac B” power plants located 100 km from Belgrade (Serbia). It was found that during transport of coal ash and slag to the dump, the water used for transport becomes enriched with manganese, nickel, zinc, chromium, vanadium, titanium, cobalt, arsenic, aluminum, and silicon, while more calcium, iron, cadmium, and lead are adsorbed by the ash and slag than is released from them. There is also an equilibrium between the release and adsorption processes of copper and magnesium during transport. The vertical penetration of the water used for transport results in a release of calcium, magnesium, manganese, and cadmium to the environment, while iron, nickel, zinc, chromium, copper, lead, vanadium, titanium, cobalt, and arsenic are adsorbed by the fractions of coal ash and slag in the dump. 相似文献