HRSG Overview
HRSG Overview
HRSG HR SG Sys System tems s - “A “An n Over Overvi view ew” ”
HRSG Overview
Mechanical & Design Benefits
HRSG Overview
Section 1 - HRSG Inlet Transition Duct
• • • • • • •
High velocity and highly turbulent region 30° / 60° Inlet Duct Configuration “Cold Casing” design internally insulated and lined 12/16 gauge stainless steel inner liner (2.67mm / 1.52mm) 12.7mm (1/2”) studs on 279.4mm (11”) centers 6mm carbon steel (SA-36) outer casing Shipped in flat panels limited in size by shipping clearance.
HRSG Overview
Section 2 – Superheaters/Reheaters
•
All welded header design to enhance reliability and lower life cycle costs
•
Fully drainable & ventable to improve cycling capability
•
Fully Top supported pressure parts allows for unrestrained thermal growth
HRSG Overview
Section 2 – Superheaters/Reheaters
HRSG Overview
Section 2 – Superheaters/Reheaters
• Staggered or Inline Tube Pitch • 38.1mm (1 1/2”), 44.5 mm (1 3/4") or 50.8mm (2”) O.D. Tubing • 88.9 mm x 88.9 mm (3.5”x3.5”) to 101.6 mm x 101.6 mm (4”x4”) tube spacing • Serrated or solid finning
HRSG Overview
Section 3 – Duct/Grid Burner System
• 3rd Party Engineered products, integrated into •
the HRSG system. Locations in the HRSG • Inter-staged firing or “up-front” firing
• Variety of fuels that can be fired: • • •
• natural gas, No. 2 oil, or heavy oil firing Horizontal/Vertical runner (element), side firing. Available with continuous/intermittent pilots, element isolation and a range of turndown. Burners, Fuel Skid, Cooling Air, BMS
HRSG Overview
Section 3 – Duct/Grid Burner System
HRSG Overview
Section 4 - Burner Outlet Transition Duct
• Cold casing design, internal insulation with external stiffeners.
• Internal Construction Options • Moderate firing < 730 °C • ceramic fiber insulation with stainless steel internal liner
• High firing > 730 °C • Y-Bloc ceramic insulation module rated to 1090°C without internal liner
• Shipped in flat panels limited in size by shipping clearance.
HRSG Overview
Section 5 – Emission Control Systems
• CO & SCR Systems • • •
3rd Party Engineered products, integrated into the HRSG system. Modularized construction to reduce overall field installation labor Configured in the system to permit access for maintenance and catalyst replacement without removal of HRSG piping/structures.
HRSG Overview
Section 5 – Emission Control Systems
HRSG Overview
Section 6 – Steam Drums
• Drum shell/heads material in • • • •
accordance with boiler codes (SA-516 Gr 70 or SA-299) Hold “retention” duration determined by specification requirements Hinged manway access 305mm x 406mm minimum Two-stage steam purification system with primary separators and secondary dryers. Shipped as completed assembly including: • Nozzle connections, steam purification equipment and internal piping, drum saddles
HRSG Overview
Section 6 – Steam Drums
Vortexes Used for Steam Separation and Circulation Alternative : perforated sheets
Chevrons Used for Steam Purification Alternative : mesh dryer
HRSG Overview
Section 7 – HP, IP, LP Evaporators
• All welded design • Fully top supported pressure parts • •
pipe support (drum support) for HP rod and clevis supports for IP and LP
• Staggered or Inline tube pitch • 38.1mm (1 1/2”), 44.5 mm (1 3/4") or 50.8mm • • •
(2”) O.D. Tubing 88.9 mm x 88.9 mm (3.5”x3.5”) to 101.6 mm x 101.6 mm (4”x4”) tube spacing Serrated or solid finning T-11, P-11 “safe ends” in upper bend areas in the LP evaporator to minimize flow assisted corrosion (FAC) damage
HRSG Overview
Section 8 - Economizers
• • • • • •
All welded header design Fully drainable and ventable Fully top supported pressure parts Staggered or Inline tube pitch 38.1 mm (1-1/2”) O.D. tubing 88.9 mm x 88.9 mm (3.5”x3.5”) tube spacing • Serrated or solid finning
HRSG Overview
Section 9 - Feedwater Heater
• Similar to other system Economizers in design approach except: •
Multiple tube and finning material options based on considerations of • • •
•
•
oxygen pitting on the tube inside surfaces gas side fouling on the tube outside surfaces acid dewpoint considerations due to sulfur in the fuels
Splitted bottom header for first pass utilized in area of water entry to avoid damage due to thermal shock Can be fabricated from Austinetic or Ferritic tube material depending on requirements.
HRSG Overview
Section 10 - LP Steam Drum
• Single or two-stage purification system can be provided depending on facility requirements for steam
• Sizing can be adjusted based on specific needs of the facility.
HRSG Overview
Section 11 - Integral Deaerator
• Horizontal or vertical • • •
configurations Tray type or Spray and Tray type designs Connected directly to LP steam drum with no intervening valves. Floating Pressure operation.
HRSG Overview
Section 12 - Stack Assembly
• Free standing, single wall design • Designed to prevailing site •
conditions based on civil/structural codes and ANSI STS-1. Isolation dampers and silencers can be included as necessary in the stack assembly.
• Supplied in a variety of arrangements based on shipping limitations and field construction needs.
HRSG Overview
Section 12 - Stack Dampers
• Installed in stack above breeching to reduce heat loss. • Counterweigted to open + interlocked into DCS for safety. • Shipped in match marked pieces after shop pre-assembly.
HRSG Overview
Section 13 - Ladders and Platforms
• Stair access on one side, ladder • • •
access on opposite side. Open bar type grating with supporting steel. 2 or 3 rail handrail system. Provided for access to equipment in the following areas: • • • •
main operating platform, both sides steam drum safety valve access stack access to emission ports and stack closure damper (if required) burner maintenance, flame observation
• Fabricated in sections that can be hot dip galvanized or painted
HRSG Overview
HRSG Constructability
• HRSG Packaging Options are based on evaluation of shipping access, shop location and site capability to provide the most economical package • • • •
“Modular Box” Design Approach (highest degree of shop assembly) “C-Section” Modular Design Approach “Field Modular” Design Approach “Field Platen Design Approach (lowest degree of shop assembly)
HRSG Overview
HRSG Constructability
• Systems are provided in various configurations to meet size and/or site limitations. 1 Wide Shop Modular
X
C-Section
O
2 Wide
3 Wide
O
Field Modular
X
X
Field Platen
O
O
X = standard O = optional
HRSG Overview
HRSG Constructability
• “Modular Box” Design Approach: •
• • •
Highest degree of shop modularization with tube bundles shipped with the casings and supporting structures shop installed. Due to shipping limitations this approach usually only applies to Single Wide HRSG systems. In some instances, steam drums and interconnecting piping can be shop installed. Requires a detailed and thorough review of shipping clearances to assure access to the site.
HRSG Overview
Loading of Modular Box for Transport
HRSG Overview
Setting of Modular Box at Site
HRSG Overview
HRSG Constructability
• “Field Modular” Design Approach •
Configuration based on maximizing the tube bundle size based on shipping limitations. • •
•
Heat transfer sections are prefabricated in modules (tube bundles) with interconnecting piping installed. Structural support steel and casing panels are shipped separtely from the modules which permits earlier site work and pre-assembly.
This approach can support either top loading or side loading of the tube bundles and can support any sequence of installation (left side first, right side first, front to rear, rear to front)
HRSG Overview
Field Modular Approach
Side Loading the first tube bundle in a “Double Wide” HRSG
HRSG Overview
Field Modular Approach
Close up of the showing degree of shop assembly
HRSG Overview
HRSG Constructability
• “Field Platen” Design Approach •
Configuration based on very low component weights to facilitate inland transportation. • Individual tube platens consisting of finned tubes and upper/lower headers are shipped loose. • Interconnecting piping is shipped loose. • Structural support steel and casing panels are shipped separtely from the modules which permits earlier site work and pre-assembly
•
Field assembly sequence is more restrictive due to installation hardware for the platens and would need to be determined prior to shipment of components.
HRSG Overview
Field Platen Approach
Uprighting and Installing a Platen
HRSG Overview
Experience
• Small-Size HRSG Hamakua, Hawaii 2 Pressure Level with Bypass System Main Steam • Flow: 33.4 t/h • Press: 64.5 barg • Temp: 513 ºC GT: GE LM2500 Fuel: Natural Gas
HRSG Overview
Experience
• Mid-Size HRSG New Brunswick, Canada Single Pressure with Fresh Air Firing Capability Main Steam Conditions • Flow: 115 t/h • Press: 43.8 barg • Temp: 329ºC Future LM 6000 Fuel: Natural Gas
HRSG Overview
Experience
• Large-Size HRSG Samalayuca, Mexico 3 Pressure Levels with Reheater + Supplemental Firing Main Steam Conditions • • •
Flow: Press: Temp:
HP 158.3 t/h HP 102.4 barg HP 532ºC
GT: GE Frame 7FA Fuel: Natural Gas