Hydrated lime clay composites for the removal of SOx from flue gas streams

摘要

The preparation and the use of base/clay composites materials as sorbents for the removal of SO2 and SO3 (SOx) from flue gas and other sulfur containing gas streams is described. The base is either an alkaline earth metal carbonate (e.g. CaCO3) or hydroxide (e.g. Ca(OH)2) and is incorporated onto the clay by hydrating a dry physical mixture of an alkaline earth metal oxide, a smectite clay and a second metal oxide, or metal oxide precursor to form a powdered composite material. The second metal oxide, preferably selected from transition metal ions, act as an oxidation catalyst for the conversion of sulfur dioxide to sulfur trioxide. The use of clay as dispersing agent for both the basic oxide and the catalytic oxide component decreases the particle agglomeration of base particles and increases the rate of SOx uptake compared to the bulk bases in current use.