To reuse a catalyst on which an arsenic compound is accumulated as a denitrating catalyst by enabling that to be regenerated by a method wherein after removing by washing a catalysis accumulated material by an alkali aqueous solution of NaOH or the like in regeneration of the denitrating catalyst of which a denitrating performance is lowered, an activating treatment of the catalyst is executed by an acid aqueous solution of HCl or the like.
On regenerating a denitrating catalyst of which a catalytic performance is lowered since a calcium content contained in a dust in an exhaust gas of a coal burning boiler is stuck to a surtace of the catalyst to generate a calcium sulfate anhydride contained in the exhaust gas, and the surface of the catalyst is covered thereby, firstly the denitrating catalyst is washed by an alkali aqueous solution, and an arsenic compound is removed from the denitrating catalyst. Then, an activation treatment of the catalyst is executed by using an acid aqueous solution. As the alkali aqueous solution to be used, aqueous solution of NaOH, Na2CO3, NaHCO3 and the like are cited, and as the acid aqueous solution to be used, aqueous solutions of HCl, HNO3 and the like are exemplified. Further, after washing the denitrating catalyst thus, if necessary, a catalysis active component is impregnated into the denigrating catalyst and supported thereby.
IIDA KOZO
OBAYASHI YOSHIAKI
