Hydrogen Production from Purge Gas Recovery of Ammonia Plant as a Feed of Solid Oxide Fuel Cell and Reduction of Greenhouse Gas Emissions

Increasing concentrations of greenhouse gases in the atmosphere and global warming is one of the most important problems that humanity is facing in recent years. One of the promising strategies for reducing the number of greenhouse gases in the atmosphere is preventing the emission of these gases by gas flaring. In this paper, the possibility of using flare gas of ammonia production unit as a feed of solid oxide fuel cell is investigated. This gas which contains a
high percentage of hydrogen should be sent into ammonia separation unit before entering the Solid Oxide Fuel Cell (SOFC). After separation of ammonia from the flue gas, the gas is fed to the SOFC directly. About 10 percent of the gas stream composed of meTEMPthane. So the meTEMPthane steam reforming reaction, water-gas shift reaction and electrochemical reaction simultaneously occur within the cell. The modeling results indicate that at the first, the power generation increases with enhancing the current density, but increasing the current density more TEMPthan 1.8 A/cm2 will decreases the generated power because the decreasing effect of voltage drop on power generation is more severe TEMPthan the increasing effect of higher current densities. Regarding this fact that carbon monoxide participates in electrochemical reactions, the output stream of SOFC contains a high percentage of water vapor and a small amount of carbon dioxide. The investigations in this paper indicate that the use of SOFC in which meTEMPthane is fully converted to hydrogen is a safe way to reduce greenhouse gas emission