Invariant properties of solid oxide fuel cell systems with integrated reformers

Abstract

openAccessArticle: Falsecover date: 2015-10-01pii: S0360-5442(15)00971-8Harvest Date: 2016-01-06 13:08:27issueName:Page Range: 452-452href scidir: http://www.sciencedirect.com/science/article/pii/S0360544215009718pubType

Feedforward based transient control in solid oxide fuel cells

“…, was shown to be valid for a wide range of hydrocarbon fuels and for multiple reformer types, [8]. The work showed the invariance to exist for intrinsically conserved variables.…”

“…In this mode, the fuel flow is manipulated based on a steady-state relationship between U , fuel flow, and current, [4]. In [8], a generalized analytical study of this relationship reveals its invariance with respect to operating conditions such as temperature, pressure and rates of reforming reactions. It can be derived under partial knowledge of the plant, for reformer based SOFCs operating with a class of hydrocarbon fuels.…”

Control of oxygen-to-carbon ratio and fuel utilization with regard to solid oxide fuel cell systems with anode-offgas recirculation: A review

“…Just as for the control strategies a common restriction for model-based concepts is a fuel gas supply with known composition or with pure methane such as in Das and Mukherjee [45], Das [84], Abeysiriwardena and Das [76], Dolenc et al [48] as well as others [17,41,43,83,85], which enables a simple calculation of the characteristic parameters.…”

“…Due to this limitation the concepts lack the potential to be transferred to a typical and commercial SOFC system, which is driven by natural gas with varying quality. The prerequisite of stationary operating conditions in [76,85] or a constant and known recirculation ratio is used in some studies [17,45,48,85], which is a simplification of the complexity in real SOFC-systems. The validation of the concepts is also often limited to simulations, such as in Das and Mukherjee [45] or Chen et al [22].…”

“…To overcome numerical problems such as convergence associated with the complex model and its implementation on a commercial programmable logic controller (PLC), the second approach simplifies the model from the first approach and is adapted for a simpler PLC implementation. Assuming a constant inlet temperature of the reformer, a linear correlation between the gas compositions at the reformer outlet and inlet is established Slippey et al [85] define analytical equations as data-driven soft-sensor for stack-FU and S/C-balance to ensure safe and optimum operation of a SOFC-system with AEGR. Stack-FU is defined as a function of the maximum hydrogen potential by complete reforming of the supplied fuel gas.…”