Energetic evaluation of high pressure PEM electrolyzer systems for intermediate storage of renewable energies
Energetic evaluation of high pressure PEM electrolyzer systems for intermediate storage of renewable energies
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DOI：
10.1016/j.electacta.2013.05.102
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发表时间：
2013-11
影响因子：
6.6
通讯作者：
B. Bensmann;R. Hanke‐Rauschenbach;I. Arias;K. Sundmacher
中科院分区：
文献类型：
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作者：
B. Bensmann;R. Hanke‐Rauschenbach;I. Arias;K. Sundmacher
从能量的角度比较了水电解法生产高压氢气的三种途径。除了两种经典的方法，包括产品气体的增压(路径I)或给水的机械增压(路径II)外，还讨论了第三种方法。它涉及到电解过程中的电化学共压缩。能量评估是基于对不同产氢途径的统一模型描述。它由能量、熵和质量的整体稳态平衡以及现代状态方程组成。由此可逆的能量需求被用来确定路径的内在热力学缺陷。对不可逆性的额外考虑允许确定由于设备特定特性造成的效率损失。对于高达40巴的氢气输送压力，经典路径的表现优于路径III。由于氢气已经在高压下生产，这就消除了耗能的机械氢气压缩的需要，并节省了由于氧气加压而产生的额外能量需求。然而，随着压力差的增加，氢的反向扩散强烈地降低了非对称电解槽的法拉第效率，这必须通过额外的能量供应来补偿。
Three pathways for high pressure hydrogen production by means of water electrolysis are energetically compared. Besides the two classic paths, comprising either the pressurization of the product gas (path I) or the mechanical pressurization of the feed water (path II), a third path is discussed. It involves the electrochemical co-compression during the electrolysis.The energetic evaluation is based on a uniform model description of the different hydrogen production pathways. It consists of integral, steady-state balances for energy, entropy and mass as well as a modern equation of state. From this the reversible energy demand is used to identify the inherent thermodynamic drawbacks of the pathways. The additional consideration of irreversibilities allows for the determination of efficiency losses due to device specific characteristics.For hydrogen delivery pressures of up to 40 bar the classical pathways are out-performed by path III. Since the hydrogen is already produced at elevated pressure this eliminates the need for an energy consuming mechanical hydrogen compression and spares the additional energy demand due to the oxygen pressurization. However, with increasing pressure differences the hydrogen back-diffusion strongly decreases the Faradaic efficiency of the asymmetric electrolyzer that has to be compensated by an additional energy supply.