Development and experimental validation of a water gas shift kinetic model for Fe-/Cr-based catalysts processing product gas from biomass steam gasification

Abstract

This paper introduces an improved kinetic model for the water gas shift reaction catalyzed by an Fe-/Cr-based catalyst. The improved model is based on a former model which was developed previously in order to consider the composition and the catalyst poisons (H2S) of product gas derived from dual fluidized bed biomass steam gasification.rφiT=117.8molgPa1.71s⋅exp−126.6kJmolR⋅T⋅pCO1.77⋅pH2O0.23⋅pCO2−0.17⋅pH2−0.121−KMALKg.\\documentclass[12pt]{minimal}\t\t\t\t\\usepackage{amsmath}\t\t\t\t\\usepackage{wasysym}\t\t\t\t\\usepackage{amsfonts}\t\t\t\t\\usepackage{amssymb}\t\t\t\t\\usepackage{amsbsy}\t\t\t\t\\usepackage{mathrsfs}\t\t\t\t\\usepackage{upgreek}\t\t\t\t\\setlength{\\oddsidemargin}{-69pt}\t\t\t\t\\begin{document}$$ \\begin{array}{c}r\\left({\\varphi}_i,T\\right)=117.8\\ \\frac{\\mathrm{mol}}{g\\ {Pa}^{1.71}\\ s}\\cdot \\mathit{\\exp}\\left(\\frac{-126.6\\ \\frac{\\mathrm{kJ}}{\\mathrm{mol}}}{R\\cdot T}\\right)\\cdot {p}_{CO}^{1.77}\\cdot {p}_{\\mathrm{H}2\\mathrm{O}}^{0.23}\\cdot {p}_{CO2}^{-0.17}\\cdot {p}_{\\mathrm{H}2}^{-0.12}\\\\ {}\\left(1-\\frac{K_{MAL}}{K_g}\\right)\\end{array}. $$\\end{document}Furthermore, this improved model has been validated with experimental data. The data was generated by a WGS reactor which employed a commercial Fe-/Cr-based catalyst and which processed real product gas from the dual fluidized bed biomass steam gasification plant in Oberwart, Austria. Basically, the validation showed good agreement of the measured and the calculated values for the gas composition (absolute errors of the volumetric fractions of up to 1.5 %) and the temperature profile (absolute errors of up to 21 °C) of the WGS reactor. Of all considered gas components, the CO concentration showed the highest error.The results qualify the improved kinetic model for basic design and engineering of a WGS reactor employing a commercial Fe-/Cr-based catalyst which processes product gas from an industrial scale biomass steam gasification plant.