Viability of Coupled Steam-Carbon-Air Fuel Cell Concept for Spontaneous Co-Production of Hydrogen and Electrical Power

Abstract

A novel electrochemical conversion scheme for the spontaneous and simultaneous production of carbon-free hydrogen and electric power is proposed and modeled. The design combines a carbon fuel cell and a steam-carbon fuel cell into a steam-carbon-air fuel cell that shares a single solid carbonaceous fuel bed in the anode chamber. A model of the combined cell is developed and a new definition for overall cell efficiency, which accounts for the hydrogen product generated, is produced. Results indicate that the proposed cell can reach efficiencies above 78%, and can also realize a six-fold increase in hydrogen production rate compared to a steam-carbon fuel cell with only a doubling of the cell active area.

Modeling the performance of direct carbon solid oxide fuel cell -anode supported configuration

“…Gür et al [7] have experimentally verified the reaction mechanism of DC-SOFC by comparing its performance with SOFC running on pure CO. Alexander et al [8] have proposed a steam carbon air fuel cell and was able to achieve efficiency of 78 % for hydrogen and electricity co-generation. Sandip Das [9] has used the dusty gas model to develop the analytical expression for the concentration overpotential of DC-SOFC. In our previous work [10], the variation of concentration profiles of CO and CO 2 across the anode electrode was studied as a function of design parameters of the cathode.…”

“…represents diameter of pore D ij and M i represent effective binary diffusion coefficient and molecular weight of species i. and  corresponds to porosity and tortuosity of the medium, P is represented in atm, T in K, M i and M j are the molecular weights of species i and j respectively, V i is the sum of the diffusion volume of component i and D ij is represented in m 2 /s.The effective binary diffusion coefficient is related to the binary diffusion coefficient by the following equation[9]:…”

The thermal effect in direct carbon solid oxide fuel cells

“…In addition to power generation, new DC-SOFC systems have been proposed and demonstrated to be feasible for simultaneous power and gas cogeneration. Alexander et al [15,16] developed a steam-carbon fuel cell for simultaneous generation of H 2 and power and the efficiency was over 78%. Xie et al [1,17] verified the CO 2 shuttling mechanism of DC-SOFCs by comparing the electrochemical characteristics of a CO-fueled SOFC with a DC-SOFC.…”

Perspective—Electrochemical Gasification: Revisiting an Old Reaction in New Perspective and Turning “Black” Hydrogen to “Blue”

“…The present article introduces the novel concept of electrochemical gasification (EG) in a steam-carbon fuel cell (SCFC) that turns "black" (includes "brown") hydrogen into "blue" by allowing simultaneous and thermodynamically spontaneous co-production of carbon-free H 2 , electricity, and a highly concentrated CO 2 stream that is practically ready for CCS. [7][8][9][10] The article further expands the SCFC scheme into nested steam-carbon-air fuel cell (SCAFC) concept that totally eliminates the need for external input of heat and/or electrical power for simultaneous production of H 2 and electricity, while at the same time produces capture-ready CO 2 for CCS.…”