Ammonia SOFC

Hydrogen sulfide (H2S), hydrogen chloride (HCl) and ammonia (NH3) are impurities typically found in coal gas. Some of these substances may be harmful to the performance of SOFCs. Recent experiments (35) have used a simulated oxygen-blown coal gas containing 37.2% CO/34.1% H2/0.3% CH4 /14.4% C02/13.2% H2O/0.8% N2. These experiments have shown no... 

Direct ammonia feed to a SOEC has been demonstrated several times (Wojcik et al., 2003 Fournier et al., 2006 Ma et al., 2006). Whether hydrogen atoms are fed as H2 or as an equivalent amount of NH3 there is little or no difference in the fuel cell output (Wojcik et al., 2003). The SOFC actually benefits from... 

With a properly designed fuel processing system, SOFC can use many available fuel types. Operating at temperatures above 600°C, SOFC can reform methane (the main component of natural gas) directly on the cell anode or operate on CO-containing gas or even on ammonia. 

Modem production methods of ammonia are very efficient, even from coal, and the existing production process involves inherent CO2 separation, enabling CO2 sequestration to be employed without additional CO2 scmbbing. Hansen et al. (2010) have studied the potential well-to-power efficiency of electricity generation using an NH3-fuelled SOFC plant from various feedstocks, and fourtd the overall efficiency of an energy chain with CO2 sequestration, even from coal feedstock, could be as high as 40%. 

Hansen J B, Madsen J, Nielsen J U and Christiansen N, Ammonia as SOFC fuel -Assessment from coal or biomass to power and heat , Proc. Lucerne European SOFC Forum, 2010, 51-58. 

Farhad and Hamdullahpur (2010) propose a novel portable fuel cell plant fueled by ammonia. In this plant a solid-oxide fuel cell (SOFC) stack consisting of anode-supported planar cells with an Ni-YSZ anode, YSZ electrolyte, and YSZ-LSM cathode is used to generate electric power. An ammonia cylinder with a capacity of 0.8 L is sufficient to sustain full-load operation of the portable system for 9 hours and 34 minutes. Computer simulation of this system predicts that for a 100-W portable device operating at a voltage of 25.6 V (a single-cell voltage of 0.73 V), an energy efficiency of 41.1% and a fuel utilization ratio of 80% are attainable. 

Zheng, K.Q., Ni, M. Sun, Q. On the local thermal non-equilibrium SOFCs considering internal reforming and ammonia thermal cracking reaction. Energy Technol. 1 (2013), pp. 35 1. 

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