4. SELECTIVE CATALYST REDUCTION (SCR)49 In order to achieve the low Nox stack emission requirements, a catalyst is to be installed in the WHRU. The catalyst life is to be 5 years. Catalyst operating50 temperature may be based on WHRU supplier recommendations from catalyst supplier and must be agreed upon by owner. The catalyst promoter shall be51 27% aqueous ammonia.5253 5. WHRU BURNER MANAGEMENT SYSTEM54 WHRU shall be designed to meet all process requirements that are specified in section 3. The supplier shall provide the calculation to confirm the actual55 temperature profile of WHRU for all operating cases. Multiple burners management with Air : Exhaust gas from GTG ratio control system may be considered56 to achieve control objective,e.g. if necessary to meet maximum film temperature requirements.