The reactivity of a copper-based flue gas desulfurization absorbent

Abstract

The reactivity of silica supported copper particles, to be used as a regenerable adsorbent for flue gas desulfurization, has been measured. Temperature-programmed reactions, both sulfatation and regeneration, were used to study the reactivity of the copper phase. Quantitative measurements of the hydrogen consumption during reduction of thoroughly oxidized and sulfated samples enabled us to calculate the degree of sulfatation after each experiment. The activity of the absorbents appeared to depend strongly on the copper particle size. The poor activity of absorbents of a low copper dispersion is attributed to diffusion limitation through a copper sulfate layer on the copper oxide particles. Simultaneous oxidation and sulfatation of metallic copper particles gives rise to a large SO 2-uptake at relatively low overall temperatures (100°C). The temperature at the surface of the copper particles will probably be higher due to the exothermicity of the reactions. Sulfatation of a pre-oxidized absorbent (copper oxide) proceeds between 300 and 400°C. Additional isothermal experiments were used to investigate the deactivation of the sorbents.