Effect of H₂S and HCl on solid oxide fuel cells fed with simulated biosyngas containing primary tar

Abstract

Integrated biomass gasifier solid oxide fuel cell systems are an alternative to fossil‐fuel‐based combined heat and power generators. However, biosyngas contaminants represent a bottleneck for small‐scale systems. In this work, we present the results of experiments on the effects of H2S, HCl, and acetic acid as model primary tar on Ni‐GDC SOFC. First, the effects of 17‐128 g/Nm3 dry basis acetic acid were studied. On a second cell, 0.8 and 1.3 ppm(v) H2S were added to the simulated biosyngas anode flow. After a full recovery, the cell was exposed to 42 g/Nm3 acetic acid and 0.8 ppm(v) H2S. On a third cell, 3.4, 20, and 50 ppm(v) HCl were tested and, after a recovery period, 42 g/Nm3 acetic acid and HCl were added. Even 0.8 ppm(v) H2S caused an immediate voltage drop. H2S affected CH4 reforming and water‐gas shift reaction. Differently, even 50 ppm(v) HCl appeared not to significantly affect these reactions. Acetic acid increased the cell voltage but caused carbon deposition at the cell inlet. The voltage increase seemed not to be affected by H2S or HCl, and no acetic acid was measured at the cell outlet, indicating that these contaminants do not affect the primary tar conversion.

Experimental Procedures & First Results of an Innovative Solid Oxide Fuel Cell Test Rig: Parametric Analysis and Stability Test

“…Similar results are found in literature for comparable button cell/single cell testing & characterization setups for varying H 2 content and temperature in terms of polarization curves [36,42,52,59,[62][63][64], but also in terms of Electrochemical Impedance Spectroscopy data analyzed with the Distribution of Relaxation Times or Equivalent Circuit Modeling techniques [40,[65][66][67].…”

Effect of H2S and HCl contaminants on nickel and ceria pattern anode solid oxide fuel cells

“…To the best of the authors' knowledge, pattern electrode cells have never been tested in an HCl environment, so no direct comparison can be made. Otherwise, in relevant studies conducted with cermet cells, no or insignificant effect on the cell performance has been reported for HCl concentration below 50 ppm [13][14][15]30,65,66]. Both reversible [16,17] and permanent [18] performance loss have been reported at higher concentrations.…”

“…(1) The effect of HCl on cell performance is negligible up to 50 ppm HCl [13][14][15] (2) High concentrations may result in reversible [16,17] as well as irreversible performance losses [18] (3) Increased temperature results in a decrease in HCl-related degradations [17] (4) Electrolyte-supported cells (ESC) are more sensitive to HCl than anode-supported cells (ASC) [18] Most of these studies rule out nickel chlorination (formation of NiCl 2 ) as a major cause of performance loss, but the adsorption of Cl species on the nickel surface has been implicated in almost all of the studies.…”

Green Synthetic Fuels: Renewable Routes for the Conversion of Non-Fossil Feedstocks into Gaseous Fuels and Their End Uses

“…Hydrogen sulfides and halogens are adsorbed on Ni/YSZ active surface inhibiting the catalytic reactions [688]. H 2 S and HCl are removed by adsorption in materials, such as activated carbon, metal oxides (ZnO, MnO, CuO), silica gel and zeolites [689], or chemical absorption in water [690].…”