(296c) Hydrogen Production Via Water Gas Shift (WGS) Over Iron and Copper Based Catalysts in Coal Derived Syngas

Water gas shift system serves as a bridging link between coal gasification and fuel cell applications in an integrated coal gasification combined cycle (IGCC) by providing hydrogen production from synthesis gas. Water-gas shift is carried out in two stages and the existing technology suffers from drawbacks such as toxicity of Cr used in the high-temperature water-gas-shift (HTS) catalyst formulation, inactivity of the HTS catalyst at lower temperatures, and metal sintering, especially for the low-temperature water-gas shift (LTS), and the low-sulfur tolerance and the need for high steam for both stages. Therefore, it is essential to develop highly active, stable and environmentally acceptable catalytic systems for WGS. In the present study, Fe-Al-Cu based catalysts have been synthesized via a simple `one-pot` sol-gel technique using different gelation agents, namely, propylene oxide and citric acid. The catalysts were tested for water-gas-shift activity in simulated coal gas containing 10% CO, 10% H2O, 7.5% H2, 5% CO2 and diluted with 67.5% N2. Samples prepared using propylene oxide has exhibited significantly higher and stable activity for hydrogen production from coal gas. The sulfur tolerance of the samples was tested after exposure to 50 ppm of H2S at 400°C for 2.5 hours. Fe-Al-Cu formulation prepared using polypropylene oxide as the gelation agent delivered 57% CO conversion at 400°C and demonstrated better sulfur tolerance than the commercial Fe-Cr catalyst. The effect of copper loading and CO/H2O ratio on the catalyst activity and sulfur tolerance were also investigated. Along with steady-state activity testing in simulated coal gas, presented results also include X-ray photoelectron spectroscopy (XPS), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), transmission electron spectroscopy (TEM) and temperature programmed experiments.