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在我国北方进入冬季,松花江水处于长达4~5月的低温低浊期,温度一般维持在3~6℃,浊度一般在6~13NTU之间.本文利用聚合氯化铝(PAC)、聚合氯化铝铁(PAFC),通过经验数据法和正交试验等方法确定最佳投药量,使剩余浊度基本上降到0.5NTU以下,并且进一步考察水中其他因素,如氨氮、硬度、COD、电导率和pH的去除情况,其中COD随着混凝剂的投加有明显的去除效果,剩余含量在0.8mg/L左右,而氨氮在0.5 mg/L上下浮动. 相似文献
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磷酸燃料电池(PAFC)电站技术的发展、现状和展望 总被引:2,自引:0,他引:2
近年来全世界都面临着能源问题和环境问题.燃料电池由于其燃料利用率高、对环境污染小的特点,成为理想的清洁、高效发电方式.磷酸燃料电池(PAFC)发电技术,在目前燃料电池电站中技术最成熟,发展最快.文中报道国外磷酸燃料电池(PAFC)电站技术的发展、现状和展望. 相似文献
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Sang Joon Seo 《Electrochimica acta》2006,52(4):1676-1682
Cr-modified Pt/C catalysts were prepared by the chemical vapour deposition (CVD) of Cr on Pt/C, and their performance as a cathode of phosphoric acid fuel cell (PAFC) was compared with the case of catalysts containing Cr added by impregnation (IMP).The catalyst prepared by CVD showed a higher activity for oxygen reduction reaction (ORR) than one prepared by IMP. There was an optimum amount of Cr that yielded the maximum mass activity of the catalyst because the gain in the intrinsic activity due to the promotional effect of Cr was counterbalanced by the loss of exposed Pt surface area as a result of the Cr introduction. Nevertheless, the activity increase at the optimum amount of Cr was greater for the CVD catalyst than for the IMP catalyst. Also, the optimum amount of Cr to yield the maximum activity was smaller for the former catalyst [Cr/Pt]CVD = 0.6, than for the latter, [Cr/Pt]IMP = 1.0.The enhancement of the Pt catalyst activity by Cr addition is attributed to two factors: changes in the surface Pt-Pt spacing and the electronic modification of the Pt surface. The formation of a Pt-Cr alloy, as confirmed by X-ray diffraction, decreased the lattice parameter of Pt, which was beneficial to the catalyst activity for ORR. X-ray photoelectron spectroscopy results showed that the binding energies of Pt electrons were shifted to higher energies due to Cr modification. Accordingly, the electron density of Pt was lowered and the Pt-O bond became weak on the Cr-modified catalysts, which was also beneficial to the catalyst activity for ORR.The promotion of oxygen reduction on Cr-modified catalysts was confirmed by measuring the cyclic voltammograms of the catalysts. All the above changes were made more effectively for catalysts prepared by CVD than for those prepared by IMP because the former method allowed Cr to interact more closely with the Pt surface than the latter, which was demonstrated by the characterization of catalysts in this study. 相似文献
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Two types of gas diffusion electrodes (GDE) with nanocarbon as structural component have been prepared and characterised by TEM, SEM, Raman, conductivity studies and fuel cell testing. 相似文献
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Suman Roy Choudhury Suhasini Roy Choudhury J. Rangarajan R. Rengaswamy 《Journal of power sources》2005,140(2):274-279
Transient state response analysis of phosphoric acid fuel cell (PAFC) cathode is important to understand various competitive processes like diffusion, reaction and product back diffusion occurring at various layers of the composite cathode. A two-dimensional unsteady state model for simulating PAFC cathode is developed as an extension of the previously developed steady-state model [S. Roy Choudhury, M.B. Deshmukh, R. Rengaswamy, A two-dimensional steady-state model for phosphoric acid fuel cells (PAFC), J. Power sources 112 (2002) 137–152]. The transient model is solved to study the impact of various parameters such as Tafel slope, diffusivity etc on the step response of the fuel cell. The effect of partial pressure variation in bulk gas for large sized PAFC cathode is also analysed. Trend analysis based on the model output is also experimentally verified using a small unit cell setup. The effect of various parameters on the settling time of the cathode, as revealed in this study, suggests possible development of a diagnostic tool employing such transient model. 相似文献
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G. Psofogiannakis Y. Bourgault B. E. Conway M. Ternan 《Journal of Applied Electrochemistry》2006,36(1):115-130
A mathematical model was developed and used to predict the performance of direct propane phosphoric acid (PPAFC) fuel cells,
utilizing both Pt/C state-of the-art electrodes and older Pt black electrodes. It was found that the overpotential caused
by surface processes on the platinum catalyst in the anode is much greater than the potential losses caused by either ohmic
resistance or propane diffusion in gas-filled and liquid-filled pores. In one comparison, the anode overpotential (0.5 V)
was larger than the cathode overpotential (0.3 V) at a current density of 0.4 A cm−2 for Pt loadings 4 mg Pt cm−2. The need for sufficient water concentration at the anode, where water is a reactant, was indicated by the large effect of
H3PO4 concentration. In another comparison, the model predicted that at 0.2 A cm−2, modern carbon supported Pt catalysts would produce 0.35 V compared to 0.1 V for unsupported Pt black catalysts that were
used several decades ago, when the majority of the research on direct hydrocarbon fuel cells was performed. The propane anode
and oxygen cathode catalyst layers were modeled as agglomerates of spherical catalyst particles having their interior spaces
filled with liquid electrolyte and being surrounded by gas-filled pores. The Tafel equation was used to describe the electrochemical
reactions. The model incorporated gas and liquid-phase diffusion equations for the reactants in the anode and cathode and
ionic transport in the electrolyte. Experimental data were used for propane and oxygen diffusivities, and for their solubilities
in the electrolyte. The accuracy of the predicted electrical potentials and polarization curves were normally within ±0.02 V
of values reported in experimental investigations of temperature and electrolyte concentration. Polarization curves were predicted
as a function of temperature, pressure, electrolyte concentration, and Pt loading. A performance of 0.45 V at 0.5 A cm−2 was predicted at some conditions. 相似文献
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Performance assessment of concentrated solar power plants based on carbon and hydrogen fuel cells 总被引:1,自引:0,他引:1
Elena Díaz Michael Epstein Manuel Romero José González-Aguilar 《International Journal of Hydrogen Energy》2018,43(11):5852-5862
In spite of the recent success on the implementation of Concentrating Solar Power (CSP), still this technology needs a substantial enhancement to achieve competitiveness. This paper provides thorough insight after previous analyses on an alternative concept for higher efficiency CSP systems based on the replacement of the power block by an electrochemical conversion system. Concentrating solar energy is herewith used to decompose methane into hydrogen and carbon, which are used in hydrogen and carbon fuel cells for electricity generation. This approach envisages modular, efficient and flexible generation plants. Dispatchability can be achieved by storing the solid carbon. Solar-to-electricity efficiency was calculated assuming thermodynamic equilibrium composition and experimental data available from literature, and compared with those of conventional power generation systems and commercial CSP plants. It is concluded that this new-generation CSP concept is potentially able to produce power more efficiently than the current state-of-the art solar thermal power plants. 相似文献