高温固体氧化物电解水制氢效率与经济性

电解水制氢因工艺简单、氢气纯度高等优点成为了科研及产业领域的热点问题。本文分析研究了高温固体氧化物电解池(SOEC)制氢过程的能量利用效率,并与碱性电解和质子交换膜(PEM)电解进行对比,进而以1000Nm~3/h电解水制氢装置为例,分析了当前高温SOEC电解制氢的成本,研究了电价与固定投资对成本的影响,并预测了其未来应用的经济性。结果表明:在高温SOEC电解所需能耗与水蒸气等预热均采用电能的条件下,其电解效率高于碱性和PEM电解。考虑利用火电厂电力和高温蒸汽进行电解水制氢整个过程,碱性电解能量利用效率仅为21.42%～26.04%,PEM电解为31.08%～33.18%,高温SOEC电解在三种工作模式下分别为38.22%、42.79%和48.98%,能量利用效率大幅提升。对于碱性电解和PEM电解,制氢总成本取决于电耗;对于高温SOEC电解,制氢总成本由电费和固定投资共同决定,降低固定投资是未来降低总成本的主要方向之一。从长期来说,碱性电解和PEM电解制氢成本将有望降至2.23元/Nm~3和1.78元/Nm~3。高温SOEC制氢成本可降至1.58元/Nm~3,有望成为市场主流技术之一。     

高温固体氧化物电解制氢模拟研究进展

固体氧化物电解池（solid oxide electrolysis cell, SOEC）是一种先进的电化学能量转化装置,具有高效、简单、灵活、环境友好等特点,是目前国际能源领域的研究热点。但SOEC在高温、密闭的复杂环境下运行,实验研究代价高昂,有些甚至无法完成。相对来说,数值模拟具有成本低、易操作的显著优势。近年来,有关SOEC电解制氢的模拟研究取得了较大进展。本文在简要介绍SOEC工作原理的基础上,从电化学、热力学和流体动力学等方面阐述了模拟基础理论,重点从稳态与瞬态及系统、宏观与微观的角度总结了高温电解制氢模拟技术的研究进展,进而指出当前研究存在的局限性。SOEC电解制氢模拟还需从数学模型验证、适用性分析、系统非设计工况和动态运行特性等方面加强研究工作。随着技术的不断发展与完善,数值模拟必将为SOEC技术商业化提供关键支撑。     

固体氧化物电解池共电解H_2O/CO_2概述

固体氧化物电解池(SOEC)是固体氧化物燃料电池的逆过程。H_2O和CO_2共电解是一种很有前景的清洁燃料制备技术,是减少CO_2排放和实现可再生能源转化储存的潜在有效途径之一,具有高效、洁净和环保的特点。利用高温固体氧化物电解池共电解技术,既可以获得高效制备合成碳氢燃料的原料气-合成气(CO+H_2),又可以达到CO_2减排的目的。本文介绍了共电解制备H_2/CO的工作原理以及热力学变化过程,综述了电解池的组成以及阴、阳极和电解质关键材料的国内外研究进展,阐述了目前存在的主要问题和下一步的研究方向。     

高温二氧化碳电催化还原研究取得新进展

正近日,中国科学院大连化学物理研究所催化基础国家重点实验室包信和与汪国雄团队在高温二氧化碳电催化还原研究中取得新进展。固体氧化物电解池(SOEC)可以将CO_2和水转化为合成气、烃类燃料并联产高纯度O_2。该电解池具有全固态和模块化结构,以及能量效率高、成本低等优点,在CO_2转化和可再生清洁     

可逆固体氧化物电池电极材料研究进展

可逆固体氧化物电池(RSOC)是一种全固态电化学能量转换装置,可以实现化学能和电能的高效洁净可逆转换,有望应用于智能电网领域实现削峰填谷以及规模化可再生能源的转化存储。由于RSOC需要分别在固体氧化物燃料电池(SOFC)及固体氧化物电解池(SOEC)模式下进行可逆、循环切换工作(存在放电/供电及氧化/还原气氛变化),对电极材料性能和物理化学稳定性要求高,迫切需要提高电极催化活性和氧化还原稳定性。介绍了RSOC的工作原理,综述了目前RSOC电极材料的研究成果及研究现状,分析了可逆对称电极材料在RSOC中的应用前景并展望了其未来的发展方向。     

甲烷直接氧化催化剂的研究进展

甲烷通过间接转化生成化学品方式已应用于工业化大生产,而直接转化方式正在攻关,以期尽快实现规模化生产。本文简要介绍了国内外甲烷直接氧化催化剂的研究背景,主要分析了甲烷直接氧化成醇、醛的催化剂研究现状,介绍了新型纳米结构催化剂、微波辅助下的催化转化,以离子液体为介质的反应系统等新领域催化剂的研究进展,并对甲烷直接氧化催化剂的应用前景进行了展望。     

高温电解水蒸汽制氢关键材料研究进展

高温电解水蒸汽制氢技术是高温固体氧化物燃料电池发电的逆过程.实现这种技术的关键是电解池材料.本文综述了高温电解水蒸汽制氢技术的优点,及国内外该项技术的研究现状和发展趋势,并简要介绍了在美国用此技术进行二氧化碳、水蒸汽共电解制备合成气体(一氧化碳+氢气)的进展情况.对高温电解水蒸汽制氢技术所涉及关键材料存在的问题进行了归...     

微生物电解池产甲烷技术研究进展

微生物电解池(microbial electrolysis cell,MEC)产甲烷技术是以微生物为催化剂,利用外界输入的电能将CO_2或有机污染物转化为甲烷的新技术。MEC在实现CO_2处置与能量转化的同时,能够处理污水、污泥、沼渣等多种污染物并生产甲烷,具有能量转化率高、生产成本低、环境友好等特点,可望成为解决能源紧缺和环境破坏问题的重要途径之一。近年来,MEC在产甲烷生物阴极结构及电子传递途径、产甲烷微生物群落等方面得到了广泛关注,同时,MEC耦合厌氧消化或其他废水处理系统形成的产甲烷新技术也逐渐研发并成为研究热点。本文综述了产甲烷生物阴极、产甲烷微生物群落等方面的研究现状,介绍了MEC耦合厌氧消化或其他系统产甲烷新技术,总结并分析了MEC产甲烷技术的研究方向和实用化过程仍需解决的技术难题。     

LSCF-GDC氧电极固体氧化物电堆高温蒸汽电解制氢性能研究

为研究基于LSCF-GDC氧电极的固体氧化物电解池堆的电解性能,自制了30单元(10 cm×10 cm)的平板式电解电堆,通过改变固体氧化物电解池堆的操作温度、水蒸气含量、气体流量等条件,记录不同条件下电解的极化曲线。分析操作条件对高温电解水蒸气极化的影响,并计算电解制氢的系统效率。结果表明较高的温度、水蒸气含量、水蒸气流量,以及氧电极空气的通入有利于降低过电位;在800℃,通入6 L×min~(-1) 90%湿度的氢气,电解电压为1.27 V时,系统效率达到最大值80.8%,此时电堆的产氢速率为4.57 L×min~(-1)。     

中科院大连化物所发布高温CO_2电解新进展

<正>中科院大连化学物理研究所汪国雄研究员和中科院院士包信和团队应邀在《先进材料》上发表了固体氧化物电解池中高温二氧化碳电解的进展报告。固体氧化物电解池可将CO_2和H_2O转化为合成气、烃类燃料并联产高纯度O_2,具有全固态和模块化结构,在CO_2转化和可再生清洁电能存储方面表现     

Conversion of Methane Facilitated by Solid Oxide Electrolysis Cells

A novel Fe-Al/SiO₂ catalyst for direct non-oxidative conversion of methane to ethylene, benzene, and naphthalene was synthesized. An Fe-Al/SiO₂ catalyst integrated solid oxide electrolysis cell (SOEC) membrane reactor design is further developed. It could be successfully demonstrated that the SOEC enabled the in situ removal of H₂, which helps to shift the chemical equilibrium of the methane conversion reaction to enhance the conversion efficiency.     

Experimental and Analytical Study of an Anode-Supported Solid Oxide Electrolysis Cell

A 1-D electrochemical model for a solid oxide electrolysis cell (SOEC) is developed and validated using published experimental data. The model combines thermodynamics, kinetic, ohmic, and concentration overpotentials to predict cell performance. For the anode-supported SOEC, good agreement is obtained between the model and experimental data, with ohmic loss being the major contributor to the cell's total overpotential. Both kinetic and concentration losses are less significant due to high-temperature operation. Due to the dominating performance loss, reducing the anode thickness is effective in diminishing the cell potential. Overall, this simple 1-D model can be employed as a design tool to evaluate component design and estimate system performance for industrial applications.     

碱性膜电解水制氢技术现状与展望

开发清洁高效的可再生能源是未来能源转型的必然趋势。氢能作为一种绿色无污染的能源载体,可通过电解水技术实现氢能与电能的高效转化,有望作为风力、光伏发电的重要调节手段。碱性膜电解水制氢能够提高电流密度,增加能量转化效率,优于碱性水溶液电解水制氢;与此同时,可采用铁、镍等非贵金属制备催化剂,克服质子交换膜电解水制氢使用贵金属催化剂带来的设备昂贵、资源受限问题。本文综述了碱性膜电解制氢技术发展现状,重点围绕自支撑催化电极、耐碱腐蚀离子膜、有序结构膜电极开展讨论,包括催化剂制备策略,耐碱离子膜发展现状,以及有序化膜电极的应用优势,阐释电化学工程中的传质与反应耦合原理。本文为进一步研究开发高性能电化学关键材料提供了指导思路,推动电解水制氢技术的发展。     

Ce掺杂La0.7Sr0.3Cr0.5Fe0.5O3-δ材料的制备及其电化学性能

近年来化石燃料大量消耗导致环境污染日益严重,固体氧化物电解池(SOEC)能够高效、环境友好地将CO₂转化为CO等高附加值化学品,因此受到广泛关注。开发高效稳定的SOEC需要采用性能优异的电极材料,La_0.7Sr_0.3Cr_0.5Fe_0.5O_3-δ(Sto-LSCrF)钙钛矿氧化物因其优异的氧化还原稳定性受到了高度重视。为进一步提高Sto-LSCrF燃料电极材料电解CO₂的能力,在Sto-LSCrF的A位掺杂Ce来调控Ce_0.08La_0.62Sr_0.3Cr_0.5Fe_0.5O_3-δ(Ce-LSCrF)中可移动氧空穴含量以便提高其对CO₂的吸附/活化能力,进而改善其电化学性能。同时对材料的相结构、氧空穴含量以及其对CO₂的吸附/脱附能力进行详细的表征和分析。此外,我们还探究了Ce-LSCrF的电化学性能,发现与Sto-LSCrF相比,Ce-LSCrF燃料电极表现出较高的电解性能,也显示出较好的恒压稳定性,电解性能的增强归因于Ce-LSCrF晶格中较多的可移动氧空位可有效吸附/活化CO₂,以上试验结果表明Ce-LSCrF是性能优异的CO₂电解材料。     

电化学耦合阴极二氧化碳还原与阳极氧化合成

电催化二氧化碳还原（CO₂RR）利用电场作用在温和的条件下将二氧化碳转化为高值化学品。将CO₂RR与热力学电势较低的阳极反应耦合,可以降低槽电压,在阳极和阴极同时生成高值化学品,提高能量效率。本文介绍了CO₂RR与氧化合成反应耦合策略,探究了电解池、离子交换膜等电解装置对CO₂RR耦合电催化性能的影响,归纳了常用于CO₂RR耦合氧化合成体系中阴阳极电催化剂的种类,重点综述了CO₂RR与氯碱过程、醇类和含氮有机物氧化等典型阳极氧化合成反应耦合的最新进展。最后,针对目前存在的阳极催化剂成本高、全电解阳极产物的分离检测困难、反应物转化率低等问题,提出开发更加高效、稳定和低成本的阳极电催化剂、升级电极结构和电解装置以及拓展新型CO₂RR耦合体系等是未来的研究方向。     

Effect of NiO/YSZ cathode support pore structure on CO2 electrolysis via solid oxide electrolysis cells

Gas diffusion within supporting cathodes of solid oxide electrolysis cells (SOECs) plays an important role in CO₂ electrolysis process. This study has investigated the effect of cathode pore structure on gas diffusion during CO₂ electrolysis. The cathode pore structure was adjusted by applying the different amounts of pore former during cathode preparation. The more pore former added produced the higher porosity of cathode and the higher limiting current density. High limiting current densities are beneficial to diminish or even eliminate gas diffusion limitation in practical applications, where the electrolysis is expected to be operated at low CO₂ concentrations to increase CO₂ conversion. An advanced impedance spectroscopy study is performed to confirm the limiting current density measured according to current-voltage curves. It was revealed that CO₂ electrolysis performance is greatly affected by gas diffusion, which is determined by the employed cathode pore structure.     

The Effects of Operating Conditions on the Performance of a Solid Oxide Steam Electrolyser: A Model‐Based Study

To support the development of hydrogen production by high temperature electrolysis using solid oxide electrolysis cells (SOECs), the effects of operating conditions on the performance of the SOECs were investigated using a one‐dimensional model of a cathode‐supported planar SOEC stack. Among all the operating parameters, temperature is the most influential factor on the performance of an SOEC, in terms of both cell voltage and operation mode (i.e. endothermic, thermoneutral and exothermic). Current density is another influential factor, in terms of both cell voltage and operation mode. For the conditions used in this study it is recommended that the SOEC be operated at 1,073 K and with an average current density of 10,000 A m^–2, as this results in the stack operating at almost constant temperature along the cell length. Both the steam molar fraction at the inlet and the steam utilisation factor have little influence on the cell voltage of the SOEC but their influence on the temperature distribution cannot be neglected. Changes in the operating parameters of the SOEC can result in a transition between endothermic and exothermic operation modes, calling for careful temperature control. The introduction of air into the anode stream appears to be a promising approach to ensure small temperature variations along the cell.     

Water electrolysis in the presence of an ultrasonic field

The energy efficiency of water electrolysis has been considerably improved in the presence of an ultrasonic field. This was demonstrated by measuring the cell voltage, efficiency and energy consumption of the generated gas from the electrolysis. These measurements were carried out in alkaline solution using linear sweep voltammetry (LSV) and galvanostatic polarization techniques. A large reduction of the cell voltage was achieved under the ultrasonic field, especially at high current density and low electrolyte concentration. With the same current density, the cell voltage difference with and without the ultrasonic field fell as the concentration of the electrolyte was increased. The efficiency of H₂ generation was improved at a range of 5-18% at high current density in the ultrasonic field but the efficiency of O₂ generation fell a little due to the difference in the behavior of the gas bubbles. The energy saving for H₂ production by using the ultrasonic field was about 10-25% for a certain concentration of the electrolyte when a high current density was used. On the other hand, the energy consumption for O₂ production with and without the ultrasonic field was almost the same.