GAS TREATMENT USING NOx-SPECIFIC REACTANT

摘要

A process for treating gas containing a NOx-specific reactant or NOx by contacting the gas with a solid absorbent comprises : removing the NOx-specific reactant from the gas using a solid absorbent comprising a nitroxy salt; or removing NOx from the gas using a solid absorbent comprising a basic material and intermittently regenerating the absorbent by the action of a NOx-specific reactant and stopping the action of the NOx-specific reactant while the absorbent contains nitroxy salt therby substantially preventing slip of NOx-specific reactant. The invention also comprises an exhaust system (10) for an international combustion engine including a NOx-trap (28), means (18) for injecting a NOx-specific reactant or a precursor of a NOx-specific reactant upstream of the NOx trap (28), whereby NOx stored on the NOx trap is reduced by the NH3 and the NOx trap is partially regenerated, thereby substantially preventing slip of NOx-specific reactant.