Selective catalytic reduction of sulfur dioxide to elemental sulfur

Abstract

Elemental sulfur recovery from SO2-containing gas streams is highly attractive as it produces a saleable product and no waste to dispose of. However, commercially available schemes are complex and involve multi-stage reactors, such as, most notably in the Resox(reduction of SO2 with coke) and Claus plants(reaction of SO2 with H2S over catalyst). This project will investigate a cerium oxide catalyst for the single-stage selective reduction of SO2 to elemental sulfur by a reductant, such as carbon monoxide. Cerium oxide has been identified in recent work at MIT as a superior catalyst for SO2 reduction by CO to elemental sulfur because of its high activi_ and high selectivity to sulfur over COS over a wide temperature range(40{3-650 "C). The detailed kinetic and parametric studies of SO2 reduction planned in this work over various CeO2-formulations will provide the necessary basis for development of a very simplified process, namely that of a single-stage elemental sulfur recovery scheme from variable concentration ,7,"as streams. The potential cost-and energy-efficiency benefits from this approach can not be overstated. A first apparent application is treatment of regenerator off-gases in power plants using regenerative flue gas desulfurization. Such a simple catalytic converter may offer the long-sought "Claus-alte:rnative" for coal-fired power plant applications.

Influence of residual K+K+ on the catalytic performance of CuO–CeO2CuO–CeO2 catalysts in preferential oxidation of CO in excess hydrogen

“…However, in the case of 5CuC-100, 5CuC-200 and 5CuC-300, peak temperatures of a peak shifted to lower temperatures from 163 to 156 C and H 2 consumptions of b peak increased from 336 to 349 mmol g À1 cat . Obviously, the lower the peak temperatures of a peak were, the higher the activity of CuO2CeO 2 catalysts in preferential oxidation of CO was [18]. But H 2 consumptions of b peak had a contrary trend with the activity of CuO2CeO 2 catalysts, indicating that b peak played a slight role on the catalytic performance of CuO2CeO 2 catalysts [19].…”

“…The PROX may be the most suitable method to reduce the amount of carbon monoxide to a level for use in electrochemical fuel cells [5]. The catalysts employed in the PROX include noble and nonnoble metal catalysts, while CuO2CeO 2 catalysts show a catalytic performance as well as, if not better than, noble metal catalysts [6][7][8][9]. Generally, preparation methods have a strong influence on the catalytic performance of CuO2CeO 2 catalysts [9,10].…”

X-ray photoelectron spectroscopy, x-ray absorption spectroscopy, and x-ray diffraction characterization of CuO–TiO2–CeO2 catalyst system

“…12 They concluded that only a small amount of copper is necessary to promote the CO oxidation. The excess of copper forms bulk CuO particles, which contributes little to the catalyst activity.…”

Gold/Ceria

“…An exponential growth of published reports on gold and the plethora of the reactions it catalyzes has taken place over the last 25 years. This system was soon followed by a detailed structural and kinetic study by Liu and Flytzani-Stephanopoulos [54]. The CO oxidation reaction was first studied on Au/CeO 2 by Hoflund and co-workers [67].…”