共查询到20条相似文献,搜索用时 250 毫秒
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燃煤火力发电厂电除尘器提效改造,应回归于除尘本质,以多依奇公式及相关理论为根本,在最大限度增加收尘面积的同时,创造多依奇公式之所以成立的假设条件,为电除尘器找到一条行之有效的技术改造路线。高效电除尘器需要具备必要的收尘面积、粉尘充分荷电(正负电荷粉尘被充分吸附)、有效清灰及科学的振打制度、二次扬尘抑制4个条件有机结合缺一不可。污染废气除尘的实质是实现气固两相的分离,静电场仅是除尘机理中的一种且受粉尘特性影响较大。多场耦合除尘技术,即在原静电场除尘基础上集成了惯性、沉降、凝聚、微旋风、静电、过滤等机理实现气与尘两相分离的同时,配合适当的清灰方式和抑尘结构,从而最大限度减少二次扬尘,实现电除尘器的超低排放。 相似文献
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新钢烧结厂3#烧结机机尾、成品筛分系统的除尘由40m2电除尘器承担.该除尘器自投入运行以来,输灰系统一直存在着严重的二次扬尘问题,生产作业和周边环境十分恶劣.该厂对输灰系统几经改造,终于解决了二次扬尘问题. 相似文献
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移动电极电除尘器是常规电除尘器的一种改进技术,采用"固定电极电场+移动电极电场"的配置形式。移动电极电除尘器末电场独特旋转的清灰方式,无振打扬尘,能有效保持极板的清洁,彻底解决了二次扬尘问题和返电晕问题,能够大大提高电除尘器效率,从而为电除尘器实现较低粉尘排放提供了一条新的工艺路线。河南某135MW机组在提效改造中采用移动电极技术,最终除尘器出口粉尘排放浓度仅为26.1mg/Nm~3。该工程的实际应用,进一步验证了移动电极技术电厂提效改造工程,特别是场地条件恶劣的项目中,具有明显优势,可为其他类似项目提供参考。 相似文献
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阴极系统的绝缘性对电除尘器的运行可靠性起着至关重要的作用,而阴极吊挂起着连接高压进线和阴极电场的作用,并绝缘隔离保温箱等宏观阳极。烟气结露和积灰对绝缘系统的影响也一直困扰着电除尘器的稳定运行。从常规阴极吊挂系统展开,改进阴极绝缘系统的热风吹扫方式,以期得到最佳解决方案。 相似文献
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常规静电除尘器无论采用何种振打清灰方式,都必然引起振打二次扬尘,且难以有效克服反电晕和极板粘灰所造成的除尘效率损失。移动电极除尘器是近几年发展起来的一种除尘设备。兰州电力修造厂近年研发这种新型除尘器,进行了一系列科研性试验工作, 相似文献
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基于计算流体动力学软件FLUENT,对某电厂1 000 MW机组的电除尘器(ESP)流场、电晕电场和颗粒运动场进行三维数值模拟,其中流场的模拟采用k-ε双方程,电晕电场采用有限体积法,颗粒相运动采用拉格朗日方法,数值计算采用SIMPLE算法,在验证该数值模拟结果合理的前提下,模拟了出口压力、烟气流速、粉尘浓度及粉尘粒径对电除尘器除尘效率的影响。结果表明:粉尘脱除效率随出口压力绝对值的减小而增大,且当出口压力维持在-3 000 Pa~3 500 Pa时,电除尘器运行稳定;在较高的烟气流速下飞灰颗粒所受惯性力增大,克服电场力逃逸收尘板捕获的能力增强,使得电除尘器收尘效率降低;当烟气粉尘浓度维持在30 g/m~3时,电除尘效率最高;粉尘粒径越大,电除尘器收尘效率越高,但增长速率减缓。 相似文献
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为减小电除尘器电流密度、降低能耗,有效抑制电晕电流,提高电除尘器后级电场的除尘效率,结合不同电晕线的制作工艺和放电特性,研制开发了一种波形电晕线,并申请了专利[1],得到广泛应用。 相似文献
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陈威祥 《福建能源开发与节约》2011,(1):23-24,47
为减小电除尘器电流密度、降低能耗,有效抑制电晕电流,提高电除尘器后级电场的除尘效率,结合不同电晕线的制作工艺和放电特性,研制开发了一种波形电晕线,并申请了专利,得到广泛应用。 相似文献
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《International Journal of Hydrogen Energy》2019,44(21):11047-11056
Cost, durability, efficiency and fuel utilization are important issues that remain to be resolved for commercialization of proton exchange membrane fuel cells (PEMFC). Anode flow mode, which includes recirculation, dead-ended and exit bleeding operation, plays an important role in fuel utilization, durability, performance and the overall cost of the fuel cell system. Depending on the flow mode, water and nitrogen accumulation in the anode leads to voltage transients and local fuel starvation, which causes cell potential reversal and carbon corrosion in the cathode catalyst layers. Controlled anode exit bleeding can avoid the accumulation of nitrogen and water and improve fuel utilization. In this study, we present a method to control the bleed rate with high precision in experiments and demonstrate that hydrogen utilization as high as 0.9988 for a 25 cm2 single cell and 0.9974 for an 8.17 cm2 single cell can be achieved without significant performance loss. In the experiments, anode pressure is kept at 1 bar higher than the cathode pressure to decrease nitrogen crossover from the cathode, decreasing the crossover from the cathode. Moreover, four load cycle profiles are applied to observe the cumulative loss in the electrochemical surface area (ECSA), which are acquired from cyclic voltammetry (CV) analysis. Experiments confirm that the ECSA loss and severe voltage transients are indicative of fuel starvation induced by prolonged dead-ended or low exit-bleed operation modes whereas bleed rates that are larger than the predicted crossover rate are sufficient to operate the fuel cell without voltage transients and detrimental ECSA loss. 相似文献
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针对国内离子渗氮炉使用中常见的问题,从减少炉壁散热损失、增加底座承重能力、提高电极连接可靠性等方面提出了改进设计方案。新的设计中取消了大部分的炉壁冷却水夹层,增加了真空隔热层,升温时减少热量损失,降温时充入压缩空气强制对流冷却,配合快速冷却装置,增加导热系数,加快工件冷却速度。采用圆弧型封头底座,增大炉体承重能力,并改善气体流动的均匀性。输电阴极采用迷宫式屏蔽结构,作为绝缘体的熔铸云母全部屏蔽在钢制外罩之内,不会因放电而损坏;阴极与底座之间采用可靠的密封方式,长期使用不漏气。实际使用表明,新型离子渗氮炉可大大降低热量损失,增加承重能力,维护保养方便;输电阴极使用3年不用拆卸,工作稳定可靠,劳动生产率比常规的离子渗氮炉提高30%。 相似文献
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Shin Ae SongSeong-Cheol Jang Jonghee Han Sung Pil YoonSuk Woo Nam In-Hwan OhTae-Hoon Lim 《Journal of power sources》2011,196(23):9900-9905
To enhance cathode performance, gadolinium strontium cobaltite (Gd0.6Sr0.4CoO3, GSC) is coated onto a porous Ni plate by a vacuum suction method, for use as the cathode in molten carbonate fuel cells (MCFCs). GSC is a mixed ionic and electronic conductor (MIEC) material, and thus has high electronic conductivity and catalytic activity at low temperatures. The electrode performance of the GSC-coated cathode is examined by various methods, such as single cell operation and electrochemical impedance spectroscopy (EIS). At 600 °C, the performance of a single cell using a GSC-coated cathode is 0.813 V. This result is very surprising given that the performance of an uncoated conventional cathode is 0.69 V. Impedance analysis confirms that a dramatic decrease in the charge transfer resistance after GSC coating is primarily responsible for the cell enhancement at low temperature. The reaction orders for O2 and CO2 at uncoated and GSC-coated cathodes are also examined via a symmetric cell test, to identify the reaction mechanism of oxygen reduction. The peroxide mechanism, which is known to be a fast reaction, is predominant for the GSC-coated cathode at low temperatures, whereas the superoxide mechanism is predominant for the uncoated cathode. 相似文献
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在一台75t/h燃煤锅炉上,设计建造了双循环流化床烟气悬浮脱硫系统,在脱硫系统运行前后,对配套电除尘器入口处烟气的温度、湿度、化学成份、粉尘的粒径、表观形貌和比电阻等相关特性进行了比较分析。结果显示,在脱硫系统运行后,可使除尘器入口处烟气的湿度增加,温度降低,尘粒的比电阻下降,从而提高了系统的脱硫效率与电除尘器的除尘效率。还研究了循环流化床烟气脱硫装置对电除尘器工作稳定性和除尘效率的影响,同时提出了应对措施。 相似文献
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Huizhi WangDennis Y.C. Leung Jin Xuan 《International Journal of Hydrogen Energy》2011,36(22):14704-14718
Air-cathode microfluidic fuel cells are promising micro-scale power sources that unfortunately undergo substantial performance loss at the cathode. This study therefore develops a mathematical model to gain a better understanding of the fundamental processes and polarization characteristics associated with the MFC air cathode operation so as to find strategies to minimize the cathode polarization. The model is solved for the four regions of an MFC cathode compartment (i.e. gas channel, gas diffusion layer, catalyst layer and electrolyte microchannel), and considers microfluidic flow, species transport, charge transport and multi-step oxygen reduction reactions. Relying on the model, transport and chemical patterns inside the MFC cathode compartment are examined. Corresponding electrode polarization behaviors are analyzed over a wide operating potential range including different forms of resistance. Through a series of model-based parametric studies, it is found that the internal transfer resistance slightly decreases with increasing catalyst layer porosity but can be effectively reduced through a proper control of electrolyte hydrodynamic conditions, indicating microfluidic technology is a powerful tool for enhancing electrochemical cells. 相似文献