The Electrochemical and Economic Modeling of a Tubular Solid Oxide Fuel Cell Stack in an Energy Generation System

The goal of this article is to present electrochemical and economic models for a tubular solid oxide fuel cell stack. To carry out this research, first, a complete electrochemical model has been employed for a single cell of the fuel cell stack, and then its activation, ohmic and concentration losses have been obtained. The results show that with the increase of the working temperature and pressure of the fuel cell, the overall voltage loss diminishes and the cell’s performance improves. On the other hand, the rise of the cell’s working temperature leads to the increase of electrical efficiency and the reduction of thermal efficiency in the cell while the increase of the cell’s working pressure doesn’t have much effect on its electrical efficiency. In this research, for the tubular solid oxide fuel cell stack at the working temperature of 1273 K, an optimal fuel utilization coefficient of about 0.8-0.85 and an inflow air-to-fuel ratio of 8.0 have been obtained. The results of economic analyses indicate that the rise in the cell’s working temperature causes the power generation capacity of the cell to increase, which reduces the price of the generated electricity as well as the costs associated with the purchase, installation and startup of the system. At the working temperature of 1273 K, the price of the generated electricity and the cost of a power generation unit with fuel cell generator have been estimated as 14 cents per kW and 1900 dollars per kW, respectively.