Design Advancements in USC Pulverized Coal Boilers. Dr Bin Xu Doosan Babcock Energy America LLC

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1 Design Advancements in USC Pulverized Coal Boilers Dr Bin Xu Doosan Babcock Energy America LLC

2 Presentation Summary The Drive for High Efficiency PC Power Plant European Status Evolution of POSIFLOW TM Furnace Design Boiler Design Improvements Conclusion Remarks

3 The Drive for High Cycle Coal Fired Power Plant Coal is the most abundant and cheapest fossil fuel source Higher market stability than oil and natural gas, guarantees to stable COE Significant growth in emerging markets (China, India) along with modest growth in mature market (USA, EU) Addition of 3 billion tons of CO 2 emissions annually More stringent regulations on emissions and carbon footprints

4 Efficiency Improvements for Emissions Reduction Today s best available USC boiler technologies offers ~18% reduction in all emissions per MW compared to traditional sub-critical boiler Cycle Efficiency (%HHV) RATCLIFFE FERRYBRIDGE HEMWEG WANGQU MERI PORI CASTLE PEAK DRAX THERMIE 700 TARGET COST 522 TARGET DBE BAT % Reduction in CO 2 emissions 0% -10% -20% -30% HEMWEG DBE BAT COST 522 TARGET Traditional Natural Circulation Boiler Advanced Supercritical Boilers THERMIE 700 TARGET

5 Benefits of Higher Steam Conditions SUBCRITICAL SUPERCRITICAL SUPERCRITICAL ULTRASUPERCRITICAL Pressure psi Main steam / reheat temp 1005F / 1005F 1060F / 1060F 1075F / 1075F 1110F / 1130 F Typical Net Plant efficiency(gross) 38% 42% 43% 45% CAPITAL COSTS Boiler island Base 1% 1.50% 2% AQCS Base -3% -4% -5% CONSUMABLES Coal Base -10% -13% -18% Limestone Base -10% -13% -18% Ammonia Base -10% -13% -18% Cooling Water Base -10% -13% -18% Auxiliary Power Base -10% -13% -18% -13% -18% EMISSIONS CO2 Base -10% -13% -18% NOx Base -10% -13% -18% SOx Base -10% -13% -18% Mercury Base -10% -13% -18% -13% -18%

6 European Status High boiler efficiency boiler plant >91.0% (HHV) with steam conditions of around 4130 psi, 1115 F / 1150 F (current state of art) Carbon capture ready POSIFLOW furnace design Single stream air and gas system, no spare mills Single cooling tower incorporating stack. Modularization to minimize construction schedule Typical European Unit

7 Evolution of Furnace Wall Technology POSIFLOW TM vertical tube low-mass-flux and spiral furnace arrangements

8 Evolution of Furnace Wall Technology Main differences between furnace arrangements for once-through boilers Mass flux at full load (lb/ft 2.s) Flow characteristic Universal Pressure High Mass Flux Design ~370 Negative Spiral Furnace High Mass Flux Design ~450 Negative POSIFLOW TM Low Mass Flux Design ~205 Positive Adjustable flow orifices Yes No No Feed-pump power High High Low Tube-to-tube temperature differences at furnace wall exit High Moderate Low Load following Bad Good Very Good Minimum load in oncethrough operation 30% 30-35% 20-25% Circulating pumps No 1 1

9 Vertical Tube POSIFLOW Furnace Significant advantages over spiral furnace boilers vertical panels and horizontal welds require less temporary support and are more accessible 4,000 fewer welds 50,000 fewer construction hours Lower steel weight by 850,000 lbs (800 MW e unit). Reduced Capital cost Reduced Construction risk Reduced Construction schedule

10 Vertical Tube POSIFLOW Furnace Advantages over spiral furnace boilers Reduced pressure drop by ~ 140 psi Lower feed pump power (~ 1 MW e ) Lower Benson load (25%) Less susceptible to variations in heat input Advantages over other vertical tube furnaces (high mass flux) Sliding pressure for 2 shift operation No orifices Lower feed pump power (800 MW e unit). Reduced Operational cost Through life benefits Simpler maintenance

11 The Supercritical Downshot Boiler - for low volatile coals (anthracite) The advent of the low mass flux vertical tube furnace for wall fired furnaces can also be applied to the downshot furnace: World s first downshot POSIFLOW TM units (2 x 600MW e ) Zhenxiong, China operation in 2010.

12 Design Improvements: Two-pass Boiler TOS SUSPENSION DECK SECONDARY REHEATER FINAL SUPERHEATER PRIMARY SUPERHEATER Recent design optimization exercise on boiler resulted in: SEPARATOR VESSELS PRIMARY REHEATER 30% reduction in pressure part weight PLATEN SUPERHEATER ECONOMISER 16% reduction in steelwork weight % reduction in Boiler Island cost BURNER LEVEL SCALE

13 Design Improvements 1 Eliminate Stub Pipes Current Modified Advantages Lowers top steel by 13 ft Reduced boilerhouse cost Reduction in shipping and transportation costs Reduced erection cost 50% reduction in slings 50% fewer welds Makes header unbalance work for you New DB method Flexibility in swanneck pipes Flexibility in tubes and roof Estimated Saving per unit: $1.75m

14 Design Improvements - 2 Separators, Roof & Vestibule Circuitry Current Design Improved Design Advantages Fewer separators Fewer risers No arch downcomers Reduced boiler width Reduction in shipping Reduced erection cost Reduced weight Doosan Babcock method Disadvantage Boiler steam/water volume reduced response to load change to be quantified not thought significant Estimated Saving per unit: $2.9m

15 Design Improvements 3 Current Integration of Hot and Cold Structures - 70% reduction in hot structure weight, simpler to erect Modularization - reduce site construction costs and saves schedule Reduce Airheater Leakage - Bisector Sec. AH + Tubular Pri. AH (2% leakage) Efficient Plate Gilled Economizer - Clear gas lanes each bank - Very resistant to erosion - Lower pressure loss - Fewer sootblowers Over 25,000 MW e of power plant with H-fin type of economizer have been installed. Recent H-fin Econ order for a 750 MW e PRB coal fired plant in US 4.5 inches 5.0 inches

16 PENTHOUSE ROOF SEPERATOR VESSEL ROOF TUBES REHEATER OUTLET FINAL SUPERHEATER PLATEN SUPERHEATER AFTER AIR BURNER BURNER BURNER HOPPER KNUCKLE m (GRADE) A B TO STORAGE VESSEL S/B THERMOPROBE S/B REHEATER INLET S/B S/B S/B S/B S/B S/B S/B S/B S/B S/B S/B S/B S/B S/B S/B F/B F/B SCALE OF METRES MAIN STEAM OUTLET ECONOMISER SCRAPER CHAIN CONVEYOR (SCC) REHEATER OUTLET B B B A B TOS TOF REHEATER PRIMARY SUPERHEATER ECONOMISER TOF TOF USC Reference Boiler for US ( PRB Coal) Design based on Doosan Babcock s best available Advanced Supercritical Boiler Technology for near term US market. Boiler Design Features: 800 MW e USC steam@ BSV : 5250 psi/1260 o F /1295 o F Sliding pressure, reheat control to 60% MCR, 25% MCR Benson load POSIFLOW furnace, two-pass, opposed wall firing Single stream (1x airheater, 1x FD Fan, 1x PA Fan, 1x SCR) 4 mills, 32 low NO x burners with OFA AH outlet gas temperature: 248 o F NO x emission: 0.03 lb/mm Btu Boiler Efficiency: 87.2% (HHV) Plant Efficiency: 42.7%(HHV) FURNACE WIDTH

17 Conclusion Remarks Raising plant efficiency by employing advanced steam conditions is the primary solution to reduce the overall plant emissions including CO 2 from coal fired power plants Today s best available USC power plant technology offers good improvement in cycle efficiency with low risk, can achieve up to 18% reduction of overall all plant emissions compared to traditional sub-critical power plants The POSIFLOW furnace is now accepted worldwide as a simple, self compensating and cost effective design USC power plant s CAPEX comparable to conventional plant for same MW e, with substantial reduction in OPEX due to less consumption in fuel and. AQCS feed stocks Doosan Babcock is taking steps to reduce the total cost of ownership of boiler plant and will continue to do so on a continuous basis

18 Doosan Babcock Energy remains committed to be an international leader in delivering advanced clean energy technologies, products and services Thank you for your attention