共查询到19条相似文献,搜索用时 125 毫秒
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文章分析了利用循环流化床锅炉燃烧技术处理制浆所产生的黑液污染问题的可行性及其应用情况,对国内造纸行业的治污技术具有一定的推广应用价值。 相似文献
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介绍了生物质燃料及生物质循环流化床锅炉特点,以及生物质燃烧过程中NOX生成机理.综述了当前国内应用较广的生物质脱硝技术,结合生物质循环流化床锅炉及烟气特性,提出低氮燃烧+SNCR脱硝工艺、SNCR+低尘布置SCR工艺较为适合生物质循环流化床锅炉NOX减排. 相似文献
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定量分析了高硫石油焦燃烧中SO2排放浓度以及必需的脱硫深度,指出石油焦与煤在循环流化床锅炉中混烧是适合我国国情的方案。 相似文献
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循环流化床锅炉添加石灰石脱硫是其特出优点之一,它具有脱硫效率高,脱硫成本低,操作简单、无水污染等特点.本文通过实例分析总结了循环流化床锅炉添加石灰石脱硫后排放与灰平衡计算方法. 相似文献
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本文阐述了煤燃烧污染中SO2的危害、控制方法和流化床燃烧中的脱硫机理。介绍了循环流化床锅炉石灰石脱硫系统设计中的问题,并提出了设计中的一些措施。 相似文献
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通过对影响循环流化床(CFB)锅炉脱硫效率的因素进行分析,根据近年有关单位的研究和国内CFB电厂的生产实践,提出循环流化床锅炉通过采取合理控制燃烧温度、循环物料量和床层物料量的优化设计、气相停留时间及固相停留时间的优化设计、采用合理的石灰石粒度、采用带有外置床的CFB锅炉等措施,可在较低的钙硫比情况下使脱硫效率达到94%以上。 相似文献
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《Resources, Conservation and Recycling》2011,55(12):1060-1066
Solid waste management is gaining significant importance with the ever-increasing quantities of industrial by-products and wastes. With the environmental awareness and scarcity of space for landfilling, wastes/by-product utilization has become an attractive alternative to disposal. Several industrial by-products are produced from manufacturing processes, service industries and municipal solid wastes. Some of these industrial by-products/waste materials could possibility be used in cement-based materials.Coal combustion by-products (CCBs) represent incombustible materials left after combustion of coal in conventional and/or advanced clean-coal technology combustors. These include fly ash, bottom ash, boiler slag, and flue gas desulfurization (FGD) by-products from advanced clean-coal technology combustors. This paper briefly describes various coal combustion products produced, as well as current best recycling use options for these materials. Materials, productions, properties, potential applications in manufacture of emerging materials for sustainable construction, as well as environmental impact are also briefly discussed. 相似文献
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Günter Scheffknecht Leema Al-Makhadmeh Uwe Schnell Jörg Maier 《International Journal of Greenhouse Gas Control》2011
Carbon dioxide emissions will continue being a major environmental concern due to the fact that coal will remain a major fossil-fuel energy resource for the next few decades. To meet future targets for the reduction of greenhouse gas (GHG) emissions, capture and storage of CO2 is required. Carbon capture and storage technologies that are currently the focus of research centres and industry include: pre-combustion capture, post-combustion capture, and oxy-fuel combustion. This review deals with the oxy-fuel coal combustion process, primarily focusing on pulverised coal (PC) combustion, and its related research and development topics. In addition, research results related to oxy-fuel combustion in a circulating fluidised bed (CFB) will be briefly dealt with.During oxy-fuel combustion, a combination of oxygen, with a purity of more than 95 vol.%, and recycled flue gas (RFG) referred to as oxidant is used for combusting the fuel producing a gas consisting of mainly CO2 and water vapour, which after purification and compression, is ready for storage. The high oxygen demand is supplied by a cryogenic air separation process, which is the only commercially available mature technology. The separation of oxygen from air as well as the purification and liquefaction of the CO2-enriched flue gas consumes significant auxiliary power. Therefore, the overall net efficiency is expected to be decreased by 8–12% points, corresponding to a 21–35% increase in fuel consumption. Alternatively, ion transport membranes (ITMs) are proposed for oxygen separation, which might be more energy efficient. However, since ITMs are far away from becoming a mature technology, it is widely expected that cryogenic air separation will be the selected technology in the near future. Oxygen combustion is associated with higher temperatures compared with conventional air combustion. Both fuel properties as well as limitations of steam and metal temperatures of the various heat exchanger sections of the boiler require a moderation of the temperatures in the combustion zone and in the heat-transfer sections. This moderation in temperature is accomplished by means of recycled flue gas. The interdependencies between the fuel properties, the amount and temperature of the recycled flue gas, and the resulting oxygen concentration in the combustion atmosphere are reviewed.The different gas atmosphere resulting from oxy-fuel combustion gives rise to various questions related to firing, in particular, with respect to the combustion mechanism, pollutant reduction, the risk of corrosion, and the properties of the fly ash or its resulting deposits. In this review, detailed nitrogen and sulphur chemistry was investigated in a laboratory-scale facility under oxy-fuel combustion conditions. Oxidant staging succeeded in reducing NO formation with effectiveness comparable to that typically observed in conventional air combustion. With regard to sulphur, a considerable increase in the SO2 concentration was measured, as expected. However, the H2S concentration in the combustion atmosphere in the near-flame zone increased as well. Further results were obtained in a pilot-scale test facility, whereby acid dew points were measured and deposition probes were exposed to the combustion environment. Slagging, fouling and corrosion issues have so far been addressed via short-term exposure and require further investigation.Modelling of PC combustion processes by computational fluid dynamics (CFD) has become state-of-the-art for conventional air combustion. Nevertheless, the application of these models for oxy-fuel combustion conditions needs adaptation since the combustion chemistry and radiative heat transfer is altered due to the different combustion gas atmosphere.CFB technology can be considered mature for conventional air combustion. In addition to its inherent advantages like good environmental performance and fuel flexibility, it offers the possibility of additional heat exchanger arrangements in the solid recirculation system, i.e. the ability to control combustion temperatures despite relatively low flue gas recycle ratios even when combusting in the presence of high oxygen concentrations. 相似文献
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Erik Jerndal Tobias Mattisson Ivo Thijs Frans Snijkers Anders Lyngfelt 《International Journal of Greenhouse Gas Control》2010,4(1):23-35
Chemical-looping combustion is a novel combustion technology with inherent separation of the greenhouse gas CO2. The technology uses circulating oxygen carriers to transfer oxygen from the combustion air to the fuel. In this paper, oxygen carriers based on commercially available NiO and α-Al2O3 were prepared using the industrial spray-drying method, and compared with particles prepared by freeze-granulation. The materials were investigated under alternating oxidizing and reducing conditions in a laboratory fluidized bed, thus simulating the cyclic conditions of a chemical-looping combustion system. The particles produced by spray-drying displayed a remarkable similarity to the freeze-granulated oxygen carriers, with high reactivity when the bed was fluidized and similar physical properties when sintered at the same temperature. This is an important result as it shows that the scaling-up from a laboratory production method, i.e. freeze-granulation, to a commercial method suitable for large-scale production, i.e. spray-drying, did not involve any unexpected difficulties. A difference noticed between the spray-dried and freeze-granulated particles was the sphericity. Whereas the freeze-granulated particles showed near perfect sphericity, a large portion of the spray-dried particles had hollow interiors. Defluidization was most likely to occur for highly reduced particles, at low gas velocities. The apparent density and crushing strength of the oxygen carriers could be increased either by increasing the sintering temperature or by increasing the sintering time. However, the fuel conversion was fairly unchanged when the sintering temperature was increased but was clearly improved when the sintering time was increased. 相似文献
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降低采油污水处理中污泥产生量技术研究——室内试验研究—— 总被引:6,自引:2,他引:4
为了降低采油污水处理过程中产生的污泥量,对“降低采油污水处理中污泥产生量技术”进行了研究,并在采油一厂文一污水站进行了为期66天的现场实验。结果表明,降低采油污水处理污泥产生量技术通过化学反应将污水中的部分离子转变为对污水净化有用的组分,并通过控制污水中的氧含量、pH及离子平衡,达到去除水中悬浮物、控制腐蚀、维持水中离子平衡的目的。当复合碱按600 mg/L加入并使系统的pH值控制在7.0~7.3且絮凝剂、助凝剂加入浓度分别为150 mg/L、100 mg/L时,污水的pH、含油量、总铁、悬浮物由处理前的6.0、109 mg/L、13.5 mg/L、78 mg/L下降为7.0、0、0~0.42、1~2,滤膜系数为35;污水腐蚀速率为0.0691 mm/a;处理后水中SRB、TGB含量分别为0、101个/mL;经中国科学院渗流流体力学研究所等单位监测和技术评价证实,处理后污水与地层水配伍性良好,对地层不伤害,所产生污泥可初步用做建筑材料。 相似文献
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Deqing Mei Shan Yue Xiaodong Zhao Klaus Hielscher Roland Baar 《International Journal of Green Energy》2016,13(11):1120-1128
Experiments were performed in a single cylinder common-rail diesel engine that adopts a low temperature premixed charge compression ignition (PCCI) mode. Combustion features of dimethyl carbonate (DMC)-diesel blends under various centers of heat release (COHRs) were revealed in details. With retarding of COHR, all the peaks of pressure and pressure rise rate and bulk gas temperature are postponed and declined in sequence. Normally, the crank angle of peak pressure is quite close to the COHR, while the peak of bulk gas temperature appears about 7°CA after COHR as a rule. The prolongation can be demonstrated at every stage of combustion such as q10 and q90 with the COHR being put backward. In addition, the heat release of diesel is completely slower than that of D10 fuel at various stages. Unfortunately, retarding of COHR implies a declining thermal efficiency of engines as well as a higher cyclic variation in general. Nevertheless, D10 blend has higher thermal efficiency than diesel thanks to high oxygen content of DMC and low boiling point that prompts better fuel atomization and complete combustion. Meanwhile, the cyclical variation of D10 is greater than diesel fuel owing to the low heat value, high latent heat of vaporization, and poor flammability of DMC. As a total, a comprehensive understanding of PCCI combustion features under different COHRs can be conducive to conducting effective management of combustion process and manipulating the subsequent emission performance to a favorable level. 相似文献
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Zhongyi Deng Rui Xiao Baosheng Jin Qilei Song 《International Journal of Greenhouse Gas Control》2009,3(4):368-375
Chemical-looping combustion (CLC) is a promising technology for the combustion of gas or solid fuel with efficient use of energy and inherent separation of CO2. The technique involves the use of an oxygen carrier which transfers oxygen from combustion air to the fuel, and hence a direct contact between air and fuel is avoided. A chemical-looping combustion system consists of a fuel reactor and an air reactor. A metal oxide is used as oxygen carrier that circulates between the two reactors. The air reactor is a high velocity fluidized bed where the oxygen carrier particles are transported together with the air stream to the top of the air reactor, where they are then transferred to the fuel reactor using a cyclone. The fuel reactor is a bubbling fluidized bed reactor where oxygen carrier particles react with hydrocarbon fuel and get reduced. The reduced oxygen carrier particles are transported back to the air reactor where they react with oxygen in the air and are oxidized back to metal oxide. The exhaust from the fuel reactor mainly consists of CO2 and water vapor. After condensation of the water in the exit gas from the fuel reactor, the remaining CO2 gas is compressed and cooled to yield liquid CO2, which can be disposed of in various ways.With the improvement of numerical methods and more advanced hardware technology, the time needed to run CFD (Computational fluid dynamics) codes is decreasing. Hence multiphase CFD-based models for dealing with complex gas-solid hydrodynamics and chemical reactions are becoming more accessible. Until now there were a few literatures about mathematical modeling of chemical-looping combustion using CFD approach. In this work, the reaction kinetics model of the fuel reactor (CaSO4 + H2) was developed by means of the commercial code FLUENT. The bubble formation and the relation between bubble formation and molar fraction of products in gas phase were well captured by CFD simulation. Computational results from the simulation also showed low fuel conversion rate. The conversion of H2 was about 34% partially due to fast, large bubbles rising through the reactor, low bed temperature and large particles diameter. 相似文献
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三效蒸发器在高含盐废水处理中的应用 总被引:1,自引:0,他引:1
在分析各种高含盐废水处理技术的基础上,介绍了三效蒸发器脱盐法,它具有技术成熟、可处理废水范围广、占地面积小、处理速度快、节能等优点,在国内具有较大的发展前景。该技术在实际工程应用中,还存在一些难点,如处理成本高、设备使用寿命短、需要蒸气量大等,亟待解决。 相似文献