Confirm What Can Be Retained
The first step was to inspect the existing injection, duct, measuring points and the space around the economizers. The retrofit boundary was defined from what could be safely reused.
Add the Catalyst at the Available Temperature Window
A medium-temperature catalyst module was installed between two economizer stages. The ammonia-water injection location was adjusted so that the existing SNCR and new SCR stages could operate as one route.
Recommission After Mechanical Changes
Injection settings could not simply be carried over from the pre-retrofit system. Flow, pressure loss, deposits and outlet response were checked again after installation.