Process for removing sulfur oxides or nitrogen oxides from a gaseous mixture in an FCC process

摘要

A collapsed composition is described which is substantially composed of microcrystallites collectively of the formula:M2m2+Al2-pMp3+TrO7+rxswhere M2+ is a divalent metal, M3+ is a trivalent metal, and T is vanadium, tungsten, or molybdenum. The microcrystallites are so small as to be undetectable through conventional x-ray diffraction techniques, yet high resolution electron microscopy reveals that a substantial portion of the microcrystallites are composed of a solid solution having aluminum oxide molecularly dispersed in a divalent metal monoxide crystal structure. Another portion of the microcrystallites are constituted by a spinel phase. The collapsed composition is suitable as a sulfur oxide absorbent, having comparatively high capacity and comparatively fast absorption and desorption rates, and is also suitable as a nitrogen oxide reduction catalyst. The collapsed composition may be produced by heat treating a layered mixed hydroxide clay having innerlayer anions in monometalate form. A sulfur oxide separation process is presented. A nitrogen oxide reduction process is also presented.