Abstract

Fuel cells are electrochemical devices that are conventionally used to convert the chemical energy of fuels into electricity while producing heat as a byproduct. High temperature fuel cells such as molten carbonate fuel cells and solid oxide fuel cells produce significant amounts of heat that can be used for internal reforming of fuels such as natural gas to produce gas mixtures which are rich in hydrogen, while also producing electricity. This opens up the possibility of using high temperature fuel cells in systems designed for flexible coproduction of hydrogen and power at very high system efficiency. In a previous study, the flowsheet software Cycle-Tempo has been used to determine the technical feasibility of a solid oxide fuel cell system for flexible coproduction of hydrogen and power by running the system at different fuel utilization factors (between 60 and 95%). Lower utilization factors correspond to higher hydrogen production while at a higher fuel utilization, standard fuel cell operation is achieved. This study uses the same basis to investigate how a system with molten carbonate fuel cells performs in identical conditions also using Cycle-Tempo. A comparison is made with the results from the solid oxide fuel cell study.

Highlights

  • There has been an increased demand for renewable energy in recent times

  • We explore the concept of coproduction with internal reforming molten carbonate fuel cell (IR-MCFC) in an identical manner using the flowsheet software Cycle-Tempo while keeping the parameters as close as possible to those used in the internal reforming solid oxide fuel cell (IRSOFC) study with which we will compare our results (Hemmes et al, 2008)

  • Outputs as high as those for the IR-solid oxide fuel cell (SOFC) system may not be obtainable with the IRMCFC system used here, we see that the maximum total output from the IR-MCFC system can still be almost three times higher compared to conventional operation

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Summary

INTRODUCTION

There has been an increased demand for renewable energy in recent times. Population and economy still rely heavily on fossil fuels and there is an urgent need for change. Coproduction of Hydrogen With MCFC cells next to the conventional products, electric power and heat, can produce hydrogen when operated at low fuel utilization, where we emphasize that the hydrogen is not pure but in the form of a gas mixture. Since it is produced in a reforming reaction of a hydrocarbon, it contains CO and CO2 next to steam and perhaps some unreacted hydrocarbon fuel. To keep our study aligned with our previous study on a SOFC system, three main modes of operation are considered as follows (Hemmes et al, 2008): 1. High-efficiency mode: input power is kept constant to 2 MW equivalent

Constant current density mode: current density is fixed at
RESULTS AND COMPARISON
CONCLUSION
DATA AVAILABILITY STATEMENT
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