Low and intermediate temperature metal supported solid oxide fuel cell operating with practical fuels

使用实用燃料运行的低温和中温金属支撑固体氧化物燃料电池

• 批准号: RGPIN-2014-04370
• 负责人: Croiset, Eric
• 金额: $ 2.55万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=637894
• 关键词: Low; intermediate; temperature; metal; supported

Solid oxide fuel cells (SOFC) are high temperature fuel cells that can achieve high electrical efficiency and be used in combined heat and power. Because of the high operating temperatures, the electro-catalyst is usually nickel, which is also an active reforming catalyst. SOFCs are, therefore, fuel-flexible and can run with natural gas, alcohol, LPG, syngas (i.e. products from gasification or reforming, usually composed primarily of CO and H2), etc. State-of-the-art SOFCs operate in the range 800-1000C. Because of such high temperatures, materials are limited to ceramic ones, thus making SOFC expensive and brittle. In order to reduce cost and improve durability and ruggedness, efforts are being made to reduce the operating temperature below 750C so that metals could be used as support; such design is called metal-supported cell (MSC). If fuel reforming is desired, the cell temperature should not be too low; for MSC, temperatures around 625-700C (Intermediate Temperature) would be ideal. If reforming is not an issue (e.g. with H2 or eventually syngas), then the cell temperature could drop in the 500-600C range (Low Temperature). An important obstacle against the direct use of hydrocarbons in SOFC is the propensity for carbon to deposit on the Ni electro-catalyst (also referred to as coking). In addition, most of the practical fuels contain sulphur, which is also a problem in conventional SOFC anodes. MSC actually offers the possibility to tackle both the coking and sulphur issues. Design of carbon and sulphur resistant MSC is the primary objective of the proposed research.The first point is that in MSC, the anode is usually comprised of Ni and some ceria-based materials, such as samaria-doped ceria (SDC). Ceria is known to increase both coking and sulphur resistance. Ceria is also active toward oxidation reactions. The second point is that in MSC, the anode can be designed so that part of the metal support becomes the primary electronic conductor of the anode; this function is usually that of Ni in non-metal supported SOFC cells. The implication is that the Ni content can be then considerably reduced. In the proposed work we are aiming at making MSC anodes with highly dispersed and non-coarsening Ni nanoparticles. We will fabricate MSC button cells following two MSC fabrication methods: 1) Ni-SDC infiltrated in YSZ backbone with YSZ electrolyte and 2) Ni-SDC co-firing with SDC electrolyte. The MSC button cells will then be tested under various conditions of temperatures and feed compositions in an electrochemical test station to assess their performance, stability, and resistance to coking and sulphur. In addition to the experimental work, we will also develop elementary-based reaction single cell simulations to serve as a design tool to optimize the anode. These simulations will be developed in Comsol Multiphysics and will be able, among others, to predict carbon deposition. The kinetics of charge transfer reactions on Ni-SDC is very important in this model, but they are currently not known. An in-depth kinetic study using pattern anode, for which we have developed some expertise, will also be carried out. Additional kinetic studies will also be pursued for chemical reactions on Ni-SDC, such as water-gas shift and CO disproportionation. The simulation will be validated using the MSC electrochemical tests over a wide range of operating conditions. The validated model will then be used to study the effect of operating and structural parameters, such as anode thickness and porosity, temperature or feed composition, in order to evaluate conditions that lead to stable operation using methane and syngas fuels. Whenever possible, those conditions will be checked experimentally.

固体氧化物燃料电池（SOFC）是高温燃料电池，可以实现高电效率并用于热量和功率。由于工作温度很高，电催化剂通常是镍，也是一种积极的改革催化剂。因此，SOFC是燃料富含燃料的，可以与天然气，酒精，液化石油气，合成气（即来自气化或改革的产品，通常主要由CO和H2组成）等。最先进的SOFC在800-1000c范围内运行。由于如此高的温度，材料仅限于陶瓷，因此使SOFC变得昂贵且易碎。为了降低成本并提高耐用性和坚固性，正在努力将工作温度降低到750℃以下，以便将金属用作支撑；这种设计称为金属支持的细胞（MSC）。如果需要燃料改革，则细胞温度不应太低。对于MSC，理想的温度约为625-700C（中等温度）。如果改革不是问题（例如使用H2或最终合成气），则细胞温度可能在500-600C范围内下降（低温）。在SOFC中直接使用碳氢化合物的一个重要障碍是碳沉积在Ni电催化剂上的倾向（也称为coking）。此外，大多数实用燃料都含有硫，这也是常规SOFC阳极的问题。 MSC实际上提供了解决焦化和硫问题的可能性。碳和耐硫的MSC的设计是拟议研究的主要目标。第一个是，在MSC中，阳极通常由NI和一些基于二氧化碳的材料组成，例如Samaria-Doped Ceria（SDC）。众所周知，秘里会增加焦化和硫磺性。陶瓷还活跃于氧化反应。第二点是在MSC中，可以设计阳极，以便金属支撑的一部分成为阳极的主要电子导体。此功能通常是非金属支持的SOFC细胞中Ni的功能。这意味着可以大大减少NI含量。在拟议的工作中，我们旨在使MSC阳极具有高度分散和非交代的Ni纳米颗粒。我们将遵循两种MSC制造方法制造MSC按钮单元：1）用YSZ电解质浸入YSZ主链的Ni-SDC和2）Ni-SDC与SDC电解质共同开发。然后，将在电化学测试站的温度和饲料组合物的各种条件下测试MSC按钮细胞，以评估其性能，稳定性和对焦化和硫的耐药性。除了实验工作外，我们还将开发基于基本的反应单细胞模拟，以作为优化阳极的设计工具。这些仿真将在Comsol多物理学中开发，并能够预测碳沉积。在该模型中，对Ni-SDC的电荷转移反应的动力学非常重要，但目前尚不清楚。也将对我们开发一些专业知识的模式阳极的深入动力学研究也将进行。还将对Ni-SDC的化学反应进行其他动力学研究，例如水电偏移和CO不成比例。该模拟将在广泛的操作条件下使用MSC电化学测试进行验证。然后，经过验证的模型将用于研究操作和结构参数的效果，例如阳极厚度和孔隙率，温度或进料组成，以评估使用甲烷和Syngas燃料导致稳定运行的条件。只要可能，这些条件将进行实验检查。