METHOD FOR SOLVING PROBLEM OF SO₂ POISONING OF LOW-TEMPERATURE SCR DENITRATION CATALYST

摘要

Disclosed is a method for solving the problem of SO₂ poisoning of a low-temperature SCR denitration catalyst. The method comprises reacting an alkaline gas and a metal sulfate deposited on the surface of the catalyst to displace a metal oxide and recover the activity of the catalyst; and decomposing an ammonium salt deposited on the surface of the catalyst through NO₂ or NO and O₂ to avoid the catalyst being covered. The method can regenerate a poisoned catalyst off-line, and also can enable the generation and decomposition of a metal sulfate and an ammonium salt on the surface of the catalyst to reach a dynamic equilibrium on-line, thus the active components of the catalyst are neither lost nor covered by an ammonium salt, achieving the purpose of resisting the SO₂ poisoning of a low-temperature SCR denitration catalyst. The method can also be used for the regeneration of other catalysts poisoned by SO₂, such as a methane catalytic oxidation catalyst poisoned by SO₂. When used on-line, the method can also transform some metal oxide dust in the flue gas into effectively active components of a catalyst. The method can effectively extend the service life of a catalyst and reduce the operating cost of an SCR system.