Boiler and modifying method thereof

A modifying method of an existing boiler having a water wall portion and an above the water wall portion, the boiler comprising a superheater system with at least one first superheater at least partially directly in the above the waterwall portion of the boiler and subjected to a first temperature heat flux, the method comprising:

• mounting an additional superheater added to the existing boiler on the waterwall portion subjected to higher temperature heat flux, in the boiler having a furnace, wherein the additional superheater is at least one of a different construction and a different material than the first superheater of the superheater system;
• connecting an output of the superheater system to an inlet of the additional superheater;
• and
• connecting an outlet of the additional superheater to a turbine for producing power.

An additional superheater for mounting on a water wall of an existing boiler subjected to a high heat flux, comprising:

• a plurality of passages arranged side by side having a first end and a second end formed as a radiant panel;
• an inlet header connected with the first end of the passages, the inlet header configured to receive superheated steam from an existing superheater system mounted at least partially in an above the waterwall portion of the boiler, the superheater system comprising a superheater formed of a plurality of individually spaced tubes for superheating steam subjected to a heat flux, wherein the additional superheater is located in the furnace to receive higher furnace heat flux than the superheater system;
• and
• an outlet header connected with the second end of the passages;
• wherein the heat flux exhibits a maximum temperature of about 540° C., and the higher furnace heat flux exhibits a temperature of about 600° C.