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: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=566477
• 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）是一种具有较高电效率的高温燃料电池，可用于热电联产。由于操作温度高，电催化剂通常为镍，镍也是一种活性重整催化剂。因此，sofc具有燃料灵活性，可以使用天然气、酒精、液化石油气、合成气（即气化或重整的产品，通常主要由CO和H2组成）等。最先进的sofc在800-1000C范围内工作。由于这种高温，材料仅限于陶瓷材料，从而使SOFC昂贵且易碎。为了降低成本，提高耐用性和坚固性，正在努力将工作温度降低到750℃以下，以便金属可以用作支撑；这种设计被称为金属支撑电池（MSC）。如果需要燃料重整，电池温度不应过低；对于MSC，温度在625-700C（中间温度）左右是理想的。如果重整不是问题（例如H2或最终合成气），那么电池温度可能会下降到500-600℃范围内（低温）。在SOFC中直接使用碳氢化合物的一个重要障碍是碳倾向于沉积在Ni电催化剂上（也称为焦化）。此外，大多数实用燃料都含有硫，这也是传统SOFC阳极的一个问题。MSC实际上提供了解决焦化和硫问题的可能性。设计抗碳和抗硫的MSC是本研究的主要目标。第一点是，在MSC中，阳极通常由Ni和一些基于铈的材料组成，例如掺杂钐的铈（SDC）。众所周知，二氧化铈可以提高焦化和抗硫性能。氧化铈对氧化反应也很活跃。第二点是，在MSC中，阳极可以设计成使金属支架的一部分成为阳极的主要电子导体；该功能通常是Ni在非金属支撑的SOFC电池中的功能。这意味着镍的含量可以大大降低。在提出的工作中，我们的目标是用高度分散和非粗化的Ni纳米粒子制作MSC阳极。我们将采用两种方法制备MSC钮扣电池：1)用YSZ电解液浸润Ni-SDC在YSZ骨架中，2)Ni-SDC与SDC电解液共烧。然后，MSC纽扣电池将在电化学试验站的各种温度和饲料成分条件下进行测试，以评估其性能、稳定性以及抗焦化和抗硫性。除了实验工作，我们还将开发基于基本反应的单细胞模拟，作为优化阳极的设计工具。这些模拟将在Comsol Multiphysics中开发，并将能够预测碳沉积。Ni-SDC上的电荷转移反应动力学在该模型中非常重要，但目前尚不清楚。此外，我们还将利用模式阳极进行深入的动力学研究，我们已经为此开发了一些专业知识。另外还将对Ni-SDC上的化学反应进行动力学研究，如水气转移和CO歧化。模拟将在广泛的操作条件下使用MSC电化学测试进行验证。经过验证的模型将用于研究操作和结构参数（如阳极厚度和孔隙度、温度或进料成分）的影响，以评估使用甲烷和合成气燃料导致稳定运行的条件。只要有可能，就用实验来检验这些条件。