scope of work Some sections of the HRSG tubes have ammonium sulfate scale from the operation of the ammonia injection grid part of the SCR system. Other sections of the HRSG tubes have rust scale from the formation of condensation on the tube and fin surfaces. Some tubes may have a combination for both types of scale. Clean high pressure economizer tube harps (HPEC1, 2, 3 & 4) in module box 3. The access for the cleaning will be from the Spool Duct section of the HRSG. Scaffolding will be erected from the floor to the ceiling adjacent to the tube harp. Clean high pressure economizer tube harps (HPEC5) and low-pressure evaporator tube harps (LPEV 1, 2 & 3) in module box 4. The access for the cleaning will be from the Spool Duct section of the HRSG. Scaffolding will be erected from the floor to the ceiling adjacent to the tube harp. Clean low pressure economizer tube harps (LPEC1, 2, 3 & 4) in module box 4. The access for the cleaning will be from the Stack Outlet Duct section of the HRSG. Scaffolding will be erected from the floor to the ceiling adjacent to the tube harp.
