压滤式碱性电解槽槽压影响因素研究

发布时间：2018-03-31 14:36

本文选题：压滤式电解槽　切入点：槽压　出处：《湖南大学》2015年硕士论文

【摘要】：随着化石燃料的不断消耗,人类正面临能源危机以及环境危机。氢能因其高效、清洁、环保等特点而受到广泛关注。碱性水电解水制氢是实现大规模制氢的主要方法之一,目前存在的主要问题是能耗高,因此降低电解槽的能耗具有重要的意义。压滤式电解槽具有结构紧凑、操作简单等优点,广泛应用于水电解制氢。本文从电极、隔膜以及电解槽结构的角度研究了电解槽槽压的影响因素。研究了预极化时间对电极的极化电位的影响,阳极预极化70mmin后,极化曲线趋于稳定,阴极预极化90min后,阴极极化曲线趋于稳定。应用稳态极化曲线法研究了不同电极在30%KOH溶液中的析氢和析氧行为,发现泡沫镍合金电极具有较好的电催化活性。研究了电极对小室槽压的影响,发现丝网结构的镍电极与泡沫结构的镍电极具有较大的比表面积,使得电极表面真实的电流密度降低。与丝网镍相比,泡沫镍结构与Raney结构具有更高的比表面积,使得具有泡沫镍结构与Raney镍结构的电极槽压低。研究了电极孔数对槽压的影响,泡沫镍电极平均槽压随着孔数(ppi)的增大而升高,对于丝网镍电极来说,小室的槽压随着目数的提高而降低。采用不同基体的泡沫镍制备镍钼合金与镍钴合金,通过测试小室槽压,发现泡沫镍基体对合金有重要影响,通过EDS测试发现,基体为ppi90、面密度420g/m2的泡沫镍的镍钴合金中钴含量最高,钴含量主要影响电极的析氧性能,钻含量越高,Co/Ni比越接近2,经过氧化之后Ni-Co表面越接近尖晶石结构,析氧性能越好。随着温度的升高,合金电极的反应活性升高,小室的槽压降低。通过研究石棉隔膜、聚苯硫醚隔膜以及聚烯烃隔膜对槽压的影响,发现聚苯硫醚隔膜具有较高的吸碱率以及较低的隔膜电阻,对离子的阻力较小,因而由隔膜以及溶液引起的欧姆降就小,槽压低。聚苯硫醚改性隔膜的厚度越小,小室的槽压就越低；隔膜厚度越小,电阻越小,对离子的电阻越小,槽压也越低。研究了电解液流量对槽压的影响,小室的槽压随着电解液流量的增加而降低。研究了电解槽结构对槽压的影响,发现极框的正面为小室的阴极时,小室的槽压最低。当钢圈孔径变大后,泡沫镍电极的槽压增大,而斜纹网镍电极的槽压减小。在电极与隔膜为零间隙时,当主极板作为连接件时小室的槽压较低,可以通过将丝网镍和泡沫镍焊接到平板镍上,从而取代主极板,降低制作工艺成本。通过增大阴极面积以及焊接电极可以增大电极与主极板之间的接触面积,降低接触电阻和小室的槽压。在电流密度3000A/m2,4000A/m2下,阴极面积增大后槽压分别降低了30mV和24mV。在电流密度为4000A/m2时,喷涂网焊接电极比不焊接的电极时的小室槽压低74mV,而平纹网镍电极焊接电极比不焊接电极的槽压低79mV。
[Abstract]:With the continuous consumption of fossil fuels, human beings are facing energy crisis and environmental crisis. Hydrogen energy is widely concerned because of its high efficiency, cleanliness and environmental protection. Alkaline water electrolysis is one of the main methods to produce hydrogen on a large scale. At present, the main problem is high energy consumption, so it is of great significance to reduce the energy consumption of electrolytic cell. The pressure-filter electrolyzer has the advantages of compact structure and simple operation, so it is widely used in the production of hydrogen by water electrolysis. The influence factors of cell voltage are studied from the angle of diaphragm and electrolytic cell structure. The effect of prepolarization time on the polarization potential of the electrode is studied. After anodic prepolarization 70mmin, the polarization curve tends to be stable, and after cathode prepolarization 90min, the polarization curve tends to be stable. The cathodic polarization curves tended to be stable. The hydrogen evolution and oxygen evolution behavior of different electrodes in 30%KOH solution were studied by using the steady-state polarization curve method. It was found that the foamed nickel alloy electrode had good electrocatalytic activity, and the effect of electrode on the cell cell pressure was studied. It was found that the nickel electrode with the wire mesh structure and the nickel electrode with the foam structure had a larger specific surface area, which reduced the real current density of the electrode surface. Compared with the nickel mesh structure, the nickel foam structure and the Raney structure had a higher specific surface area. The effect of the number of holes on the cell pressure is studied. The average cell pressure of nickel foam electrode increases with the increase of the number of holes. The tank pressure of the cell decreases with the increase of mesh number. Nickel molybdenum alloy and nickel cobalt alloy are prepared from different matrix nickel foam. By measuring the chamber trough pressure, it is found that the foam nickel matrix has an important influence on the alloy. The results of EDS test show that the nickel foam matrix has an important effect on the alloy. The nickel cobalt alloy with surface density 420g/m2 has the highest cobalt content, and the cobalt content mainly affects the oxygen evolution performance of the electrode. The higher the drilling content is, the closer the ratio of Co / Ni is to 2, and the closer the surface of Ni-Co is to the spinel structure after oxidation. The better the oxygen evolution is, the higher the reaction activity of the alloy electrode is and the lower the tank pressure is with the increase of temperature. By studying the influence of asbestos membrane, polyphenylene sulfide membrane and polyolefin membrane on tank pressure, it was found that the membrane had higher alkali absorption rate and lower membrane resistance, and the resistance to ions was lower. As a result, the ohmic drop caused by the diaphragm and the solution is small and the trough pressure is lower as the thickness of the modified membrane is smaller, and the thickness of the diaphragm is smaller, the resistance is smaller, the resistance to ions is smaller, and the cell pressure is lower. The effect of electrolyte flow rate on the cell pressure is studied. The cell pressure decreases with the increase of electrolyte flow rate. The effect of the cell structure on the cell pressure is studied, and it is found that the front of the pole frame is the cathode of the cell. The trough pressure of the chamber is the lowest. When the aperture of the steel ring increases, the groove pressure of the foamed nickel electrode increases, while the groove pressure of the twill net nickel electrode decreases. When the gap between the electrode and the diaphragm is zero, the trough pressure of the chamber is lower when the main pole plate is used as the connector. Wire mesh nickel and foamed nickel can be welded to plate nickel, thereby replacing the main electrode plate and reducing the process cost. By increasing the cathode area and the welding electrode, the contact area between the electrode and the main electrode can be increased. At the current density of 3000A / m ~ 2 ~ 4000A / m ~ 2, when the cathode area increases, the cell voltage decreases by 30mV and 24mV, respectively, when the current density is 4000A/m2, The welding electrode of sprayed mesh is lower than that of non-welded electrode by 74mV, while the welding electrode of flat mesh nickel electrode is lower than that of non-welded electrode by 79mV.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ116.21

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