The present invention provides suitable magnesia-rich sorbents for fluidizable catalysts or contact solids, methods for using such materials to reduce the emissions of sulfur compounds from industrial processes, and methods for preparing such contact solids or catalysts. The conversion, processing or burning of sulfur-containing fossil fuels can result in the emission of sulfur-containing compounds, such as H2S and SOx, to the atmosphere. To comply with increasingly stringent environmental regulations, materials are sought to reduce the emissions of sulfur compounds from industrial processes. Several methods of desulfurization are currently being used commercially. These methods include flue gas scrubbing as well as various fixed bed, ebullating bed, and fluid bed catalytic reaction processes. Some of these processes treat the flue gas just prior to the release of gas to the atmosphere.
Other processes are performed upstream of the emission release in order to prevent the undesired emission from occurring. The goal of such processes is to reduce emission of sulfur-containing compounds into the atmosphere.
Industry is lacking an economic and effective sorbent composition for economically removing sulfur oxides from emissions from a variety of industrial processes, such as fluidized bed cracking of heavy petroleum or additive contact solids for use in cold side combustion effluent treatment. Further, the industry lacks effective and economical methods for using a fluidized bed of particles to remove sulfur oxides from emissions.
A structural description of the class of “brucite” crystals is found in the work of Pinnavaia et al (U.S. Pat. No. 5,358,701, incorporated by reference). Briefly, the metal oxide layers of these crystals consist essentially of magnesium oxide (magnesia, MgO) configured structurally such that it contains octahedral hydroxy groups. A trivalent metal oxide, such as alumina (Al2O3), can be inserted into the brucite crystalline lattice in the octahedrally-coordinated metal oxide layer. Some of these brucitic materials are known as sorbents per se (see U.S. Pat. No. 5,928,496). Other brucitic materials are known as binders for sorbent contact solids.
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