Gas turbine single plant modifying method, a catalyst re-using method and a re-produced catalyst

摘要

A high temperature denitration catalyst of a gas turbine single plant contains TiO₂, at least one of WO₃ and MoO₃ and V₂O₅ of 0.5 wt % or less, preferably 0.2 wt % or less, or none of V₂O₅, and is optimized to be used in a temperature range up to a maximum 450 to 600° C. The used high temperature denitration catalyst is immersed into a V-containing water solution and dried and/or burned. An intermediate temperature denitration catalyst is produced containing a V₂O₅ component of 0.5 wt % or more, preferably 1.0 wt % or more, and is optimized for use in a temperature range of 250 to 450° C. This intermediate temperature denitration catalyst is re-used in a combined cycle plant after being modified or in other plants.