Development in. Coal Fired Power Plants with CCS

Transcription

1 Development in Oxyfuel Combustion Technologies for Coal Fired Power Plants with CCS (Part 1: Boiler and Burner Development) Stanley Santos IEA Greenhouse Gas R&D Programme Cheltenham, UK Instituto de Inginieria UNAM 28 th March ac 2012

2 CO2 Capture Options EPRI

3 Oxy-Coal Combustion Power Plant Air Oxygen Air separation Recycled flue gas Vent Fuel Boiler Cooling Purification/ (+FGD) compression CO 2 Steam Steam turbine Power 3 3

4 Oxy-Combustion Technology Use of oxygen instead of air in a boiler Oxy- Combustion is a feasible option for power plant with CO2 capture. With significant R&D investment in the past decade, this technology has achieve a maturity similar to the other leading options for power generation with CCS Outline for Presentation Boiler and Burner Development Air Separation Unit Flue Gas Processing Unit CO2 Processing Unit 4 4

5 Oxyfuel Combustion Overall Schematic Diagram 5

6 Where Can You Extract the Recycled Flue Gas (RFG) (For Practical application using low S coal) 6 6

7 Oxyfuel Combustion Technology BOILER AND BURNER DEVELOPMENT 7

8 Development of Oxy-Fuel Combustion Application in Industry Adapted from slide of Sho Kobayashi, Praxair Pictures from IFRF, Air Liqiude, Asahi Glass, Linde Gas 8 8

9 Historical Perspective The Early Days 1982: Initial suggestion by Abraham et. al. (OGJ) of using Oxy-Coal Combustion to produce CO2 for EOR 1 st public document looking at capturing CO2 from flue gas using oxy-combustion. However... as early as 1970 s work has started din the development of oxy-coal combustion with recycled flue gas 1974: Japan initial conception of using oxy-coal combustion for power generation. (To reduce pollution?) 1978: Economic feasibility of oxy-coal combustion was investigated for EOR application (H. Farzan, Babcock & Wilcox / A. Wolsky, ANL) 9 9

10 Technology Development Japan s initial conception of oxyfuel combustion application for power generation (1974) Oxygen 3rd Workshop, IEAGHG International Oxy-Combustion Network, Yokohama, Japan 10

11 ANL - EERC Study World s 1st Oxy-Coal Combustion Industrial Pilot Scale Study Tower Furnace (~ 3MWth) 11

12 Convective Section of the boiler heat transfer profile ash deposition and fouling issue Burner design issue Ignition flame stability devolatilisation & char burnout Radiant Section of the Boiler heat transfer profile slagging issue firesideid corrosion issue Prior to any retrofit of carbon capture technology, it is essential to repower the plant in order to achieve the highest possible efficiency 12 12

13 Composition of Comburent (Oxidant) Gas Composition Oxy Coal Combustion Air Fired Case %v (dry) Primary RFG 2ndary RFG Nitrogen (N2) Oxygen (O2) Argon (ar) Carbon Dioxide CO2) Water (H2O) %v (wet) < 2 (depend on %RH) ** Calculation based on ~3% air ingress, 95% O2 purity and C 6.87 H 5.56 O 0.56 N 0.13 S

14 Composition of Flue Gas from Boiler Gas Composition %v (dry) AirFired Case Oxy Coal Combustion Case Nitrogen (N2) Oxygen (O2) 3 4 (~3.5) 2 5 (~3.5) Argon (ar) Carbon Dioxide CO2) Water (H2O) %v (wet) ** Calculation based on ~3% air ingress, 95% O2 purity and C 6.87 H 5.56 O 0.56 N 0.13 S

15 Recyled Flue Gas Ratio Impact to the Flame Properties R = m RFG m PFG + m RFG 15

16 Optimum Recycle Ratio (Optimum recycle ratio is defined by the amount of Recycled Flue Gas to match the heat transfer profile of conventional air fired operation) Some of the reported results for the optimum flue gas recycle ratio Burner Rating Type of Flue Gas Molar Ratio 1 (CO2 + H2O)/O2 %O2 in Comburent 2 Recycle Ratio MRFG/(MRFG + MPFG) ANL EERC 3 MWth partially dried RFG (~18%v moisture) % (wet) - wet RFG (~35% moisture) % (wet) ~ 0.68 IFRF 2.5 MWth wet RFG (~ 26% moisture) ~ % (~41% wet) ~ 0.58 IHI 1.2 MWth wet RFG - ~34% (30%wet) - CANMET 0.3 MWth wet RFG - 35% (dry) - 1 Molar ratio of the secondary comburent (oxidant) 2 % oxygen through the burner throat (volume dry basis) 3 MRFG and dmpfg are the mass flow rate of the recycled flue gas and product flue gas respectively 16

17 Recycle Rate and Oxygen Concentration Universität ität Stuttgarttt t a) b) Flue Gas with Fly Ash Oxygen y O2, mix t adiabatic Coal Heat Output Bottom Ash Source: A. Kather,

18 Factors affecting Recycle Ratio Critical factors affecting the optimum m amount of recycled flue gas Burner and boiler design (heat transfer and flame stability oxygen distribution through burner) Air ingress Purity of oxygen from the ASU Coal type Level of moisture content in comburent Comburent (oxidant) temperature 18 18

19 Flame Description Impact of Recycle Ratio (Courtesy of IFRF) Figure 3(a): normal air-fired operation Figure 3(b): O 2 -RFG flame with recycle ratio = 0.58 Figure 3(c): O 2 -RFG flame with recycle ratio = 0.76 Figure 3(d): O 2 -RFG flame with recycle ratio =

20 Coal Flame Photos: Air Fired vs Oxy-Fired (Courtesy of IHI) Air mode(o 2 :21%) Oxy mode(o 2 :21%) Oxy mode(o 2 :30%) 20 20

21 Coal Flame Photos: Impact of Recycled Flue Gas (Courtesy of IFRF) Recycle Ratio = 0.58 (~ 0.61 include the CO2 to transport coal) Recycle Ratio =

22 Effect of Different Oxygen Concentrations (and Recycle Rates) on Flame Pattern Universität ität Stuttgarttt t Air Oxyfuel Oxyfuel 28% O 2 38% O 2 Recycle rate 77% Recycle rate 66% Source: J. Smart,

23 Ratio of Convective Heat Transfer Coefficient (Courtesy of IFRF) h1 Re1 Pr = h 0 Re 0 Pr n k k Effect of Recycle Ratio on Convective heat transfer coefficient [IFRF APG1 Trials] 23 23

24 Radiative Heat Flux Measurements (Courtesy of IFRF) Ellipsoidal Radiometer Results were also obtained by: ANL-EERC CANMET Data from Narrow Angle Radiometer is necessary for radiation modelling development Radiative Flux Using Ellipsoidal Radiometer in Air (Baseline) and O 2 /RFG (Flames B with recycle ratio = 0.73 and Flame C with recycle ratio = 0.58) IFRF APG2 Trials Research in the past decade has achieved better understanding to eh Radiation Principle of oxyfuel boiler 24

25 Results: Radiative HT- South African coal Dry Recycle m 2 Radiat tive Heat Flux kw/m Furnace Heat Flux Measurements South African coal, Oxyfuel (3% O 2 ) SAcoal/Air - 3% O2 Oxyfuel RR 65% Oxyfuel RR 68% Oxyfuel RR 70% Oxyfuel RR 72% Oxyfuel RR 75% Axial Distance from Burner, mm 25

26 Normalised Convective & Radiative heat flux Russian Coal - Dry Recycle tic e ed Adiabat emperature Normalise Flame Te Dry Oxyfuel Operation Normalised to Air Operation Peak Radiation Flux, Convective heat transfer and calculated flame temperature 1.6 Russian coal Measured Convective Heat Transfer Coefficient i indicates 74% Recycle is "Air-equivalent" Normalised Flame Temperature (calculated) Peak Normalised Heat Flux (measured) Normalised Convective HTC (measured) New Build Retrofit Avoid Calculated dry oxyfuel adiabatic flame temperatures are equivalent to air at 69% recycle Measured Peak Radiative data indicates 74% Recycle is "Airequivalent" % 65% 70% 75% 80% Effective Recycle Ratio e and ux ed Radiative ctive Heat Flu Normalise Convec 26

27 Considerations in the Boiler Operation O2 Purity and Air Ingress (a.) Why not 99+% O2 Purity (b.) Air Ingress A Challenge for the Operator 27

28 Issue of Air Ingress (Air In-leakage) Air Ingress in the boiler is a fact of life!!! 1 st Large Scale Demonstration of Oxy-Coal Combustion (35MWth) What Are the Lesson Learned... 28

29 Problem with Air Ingress 1 st Large Scale Oxy-Coal Combustion Burner Test Experience - International Combustion Ltd. 30 MWth Low NOx burner Because of Air Ingress the desired CO2 composition (only ~ 28% dry basis). Air Ingress in boilers approx. 3 % of flue gas flow for a new conventional power plant up to 10 % over the years for power plants in use 29

30 CO 2 Recovery Depends On Feed Composition Recovery Feed Composition At -55 C C, 30 bar 30

31 NOx Emissions We have quite a good confidence in - We have quite a good confidence in knowing the trend of these emissions

32 NOx Emissions (Results from ANL-EERC and IFRF) 32 32

33 Results from IFRF study (APG4) 33

34 SO2 Emissions - Highly dependent on how sulphur is captured in ash... - without the removal of SO2 in the secondary RFG, it should noted that a maximum of ~30% reduction could be expected (on mass per unit energy input basis)

35 SO2 Emissions (Results from ANL-EERC and IFRF) Emissions (lb/m MMBtu) SO EERC ANL (Wet RFG) EERC ANL (Dry RFG) 0.1 Air Fired Case [CO2 + H2O]/[O2] Molar Ratio of Comburent 35 35

36 SO2 Emissions (Results from IFRF) 36

37 Sulphur in ash 37 37

38 Fundamental question in attempt to explain the reduction of SO2 Reduction of SO2 under oxy-coal combustion conditions - Could this observations due to 2 competing phenomena in the furnace and in the convective section??? High htemperature t sulfation of fthe ash h( (as proposed dby Okazaki et. al.) - which could be in agreement base on the data of IFRF (APG2 Trials). Sulfur capture in ash at convective section enhanced by higher SO3 formation, higher deposition rate and lower carbon in ash

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43 Results from IFRF study (APG2) 43 43

44 Issue of SO3 - The confirmation of the ANL results as presented from the results of IVD Stuttgart, ttgart IHI/Calide Project, Vattenfall, Chalmers University. - Nonetheless, there are still a lot of, confirmation to be done!!!

45 Oxy-Combustion: o KEY ISSUES S SO3 issue is a big missing link! (4 years ago) ANL study (1985) have indicated that SO3 formation is 3 to 5 times greater as compared to conventional air firing mode We need to know more about the potential From Chemical Engineering Progress (Vol. 70) operational issue

46 SO3 formation is increased in the presence of firon oxide in the ash Marrier and Dibbs (1974) Thermochmica Act (Vol. 8) 46 46

47 SO 2 captured along the convective part (down to 450 C) by different inlet concentrations 500 KK_Captured RH_Captured LA_Captured EN_Captured SO 2 flue-g gas path [ppm] SO 2 injection increased SO 2 measured at the end of radiative section [ppm] Oxy-fuel 27 % O 2 47

48 IHI Callide Project Results (SO2 Emissions) IFRF (APG1 Trials) Gottelborg coal 500 CoalA CoalB SO2,O xy m ode (mg/mj) CoalC ANL-EERC Trials Blk. Thunder coal SO2,A ir m o de (m g/ M J ) SO2 Emissio ons (lb/mmbtu) EERC ANL (Wet RFG) 0.1 EERC ANL (Dry RFG) Air Fired Case [CO2 + H2O]/[O2] Molar Ratio of Comburent

49 Would the capture of SO2 / SO3 in the ash enhanced by lower carbon in ash? Marrier and Dibbs (1974) Thermochmica Act (Vol. 8) E.ON UK Results at 26%O

50 Emissions SO E.ON 2012 年 3 月 29 日, E.ON UK, Page 50

51 Ash Related Issue Data from the trials taken by: MBEL (Doosan Babcock), Air Products, Ulster University and Naples University (1995) 51

52 Summary SO2/SO3 and Sulphur in Ash (1) Capture of sulphur in ash at the furnace section is primarily due to the high temperature direct sulphation mechanism as suggested by Okazaki et. al. (2001) as shown in their experimental results. This is pretty much in agreement to the in-flame SO2 measurements done by IFRF during their APG2 trials. Okazaki et. al. suggested that this is due to promotion of capture of sulphur by CaO species and the inhibition of the decomposition of CaSO4 This mechanism is further supported from the results of IVD Stuttgart (Maier et. al.) and Imperial College (Wrigley et. al.) indicating the occurrence of both carbonation and sulphation in the ash collected from oxy-coal combustion trials. This could indicate that equilibrium reactions promoting the formation of CaCO3 and CaSO4 are probably favoured (or highly enhanced) under CO2 rich environment. These results established the feasibility of using in-furnace SO2 reduction by using Ca(OH)2 or CaO injection. 52

53 Summary SO2/SO3 and Sulphur in Ash (2) Additional sulphur capture in ash could also be promoted by increased formation of SO3. It should be recognised that both results s from ANL-EERC and IVD Stuttgart confirms that SO3 formation is higher (about 4-5 times in terms of mass SO3 emissions per unit energy input) as compared to air fired case. However, it is not yet clear if level of recycled SO2 has it impact to the level of SO3 formation. Capture of sulphur by this mechanism would occur along the flue gas path (during the convective section) as shown in the results by IVD- Stuttgart. o Furthermore, IVD-Stuttgart results indicated that the higher the level of SO2 are recycled, the capture efficiency of sulphur in ash is more efficient. o Nonetheless, it should be noted that that this observation in sulphur capture efficiency is coal dependent. 53

54 Summary SO2/SO3 and Sulphur in Ash (3) Results from Marrier and Dibbs (1974) further support the observations made by IVD Sttuttgart: maximum conversion of SO2 to SO3 would occur around o C. Capture of sulphur in ash could be dependent on the concentration of CaO and MgO in the ash. (This could probably be one of the reasons why capture efficiency of sulphur becomes coal dependent) Iron oxides could enhanced the formation of SO3 therefore promoting the capture of sulphur in the ash at the convective section. (This could probably be one of the reasons why capture efficiency of sulphur becomes coal dependent). Carbon in ash could diminish the efficiency in the capture of sulphur in ash. This is supported by various studies indicating a lower carbon in ash during oxy-coal combustion trials (IHI, IFRF, ANL-EERC) showed a lower SO2 emissions (i.e. higher degree of sulphur capture in ash). A higher carbon in ash by E.ON UK experimental results indicated a nearly similar SO2 emissions to the air fired case. Higher ash deposition rate under the wet RFG trials could also promote higher sulphur capture in the convective section. This should be further validated! 54

55 SO3 Emissions (Results from ANL-EERC, IVD Stuttgart, Callide/IHI) SO3 Concentra ation (ppm m) ANL Air IVD Stuttgart Air Callide IHI Coal A Air Callide IHI Coal B Air ANL Oxy IVD Stuttgart Oxy Callide IHI Coal A Oxy Callide IHI Coal B Oxy SO2 Concentration ti (ppm) 55

56 My Background Analysis SO2 to SO3 conversion will most likely to occur at the convective section Marrier and Dibbs (1974) Thermochmica Act (Vol. 8) 56 56

57 Similar SO 3 Conversion Rate As Air Firing - Economizer Outlet Measurements in BSF Illinois Bituminous Economizer Outlet t SO 3 results North Dakota Economizer Outlet t SO 3 results SO3 ppm mv Air Oxy w/o SOx control Oxy w/sox control 3% 2% 1% Conversion SO3 ppmv Alstom 15MW th BSF Lignite SO 3 Testing - Economizer Outlet Air Oxy w/o SOx control Oxy hot FGR Oxy w/so3 spike 3% 2% 1% Conversion 0 0 5,000 10,000 15,000 SO2 ppmv ,000 1,500 2,000 2,500 3,000 3,500 SO 2 ppmv Similar SO2 to SO3 conversion rates ALSTOM All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

58 Burner Development for Oxyfuel Combustion Burners are critical to combustion, emissions, and thermal efficiency / capacity of the utility boilers Critical importance to burner development is a full scale testing This is an important exercise to establish reference data that could be used in the development and validation of different modeling tools. This is also to gain experience in operating full scale burner. (i.e. start up/shut down, flame stability, efficiency, heat transfer, fouling and slagging, etc )

59 Burner Development for Oxyfuel Combustion Development of Full Scale Burner Testing Programme could either be accomplished by: Retrofitting of Full Scale Burner Test Rigs o B&W s 30MWth CEDF Facility (Ohio, USA) o Doosan Babcock s 40MWth MBTF Facility (Renfrew, Scotland) o Alstom s 15MWth BSF Facility (Connecticut, USA) Testing in a Full Chain Oxyfuel CCS Pilot / Demo Plant o Vattenfall s Schwarze Pumpe Pilot Plant (Cottbus, Germany) o CS Energy s Callide Power Plant (Queensland, Australia) o TOTAL s Lacq Facility (Lacq, France) o CIUDEN Demo Facility (El Bierzo, Spain) 59

60 Today... There are 3 Major Full Scale PC Burner Testing Facilities Worldwide Retrofitted for Oxyfuel Babcock and Wilcox (B&W) Doosan Babcock Alstom Power Plant Lab. 30MWth CEDF Barberton, Ohio, USA Start of Operation: Oct MWth in 90MWth MBTF Renfrew, Scotland, UK Start of Operation: Jun MWth in 30MWth BSF Windsor, Connecticut, USA Start of Operation: Nov Wall Fired Burner Wall Fired Burner T-Fired Burner Development Development Development Courtesy of Alstom, B&W and Doosan Babcock 60 60

61 OxyCoal 2 Demonstration of an Oxyfuel Combustion System Officially opened on 24 th July 2009 Doosan Power Systems 40MW th OxyCoal demonstration became the world s largest demonstration of an oxyfuel combustion system September 2011 D W Sturgeon

62 OxyCoal 2 Demonstration of an Oxyfuel Combustion System Safe and smooth transitions between air and oxyfuel operation were demonstrated, with realistic CO 2 levels achieved (in excess of 75% v/v dry, and up to 85% v/v dry). Oil Air Firing i (TFGR, PA, SA) Secondary Air to Secondary Flue Gas Recycle Transition Oil Air/Oxyfuel Firing (TFGR, PA, SFGR) Oil/Coal Air/Oxyfuel Firing (TFGR, PA, SFGR) Coal Air/Oxyfuel Firing (TFGR, PA, SFGR) Primary Air to Primary Flue Gas Recycle Transition Coal Oxyfuel Firing (TFGR, PFGR, SFGR) September 2011 D W Sturgeon

63 OxyCoal 2 Demonstration of an Oxyfuel Combustion System 40MW th OxyCoal burner turndown proven from 100% load to 40% load. 40MW t 32MW t 24MW t 16MW t 20MW t Stable rooted flame maintained for all loads down to 40% with coal ignition within the burner throat/quarl. Comparable turndown to Doosan Power Systems commercially available air firing low NO X axial swirl burners. 14 September 2011 D W Sturgeon 63

64 View on Oxyfuel Pilot Plant 64 Lars Strömberg, IEAGHG OCC2 Australia

65 Results until May 2011 Operating hours Captured amount of CO t CO 2 -removal rate > 93 % CO 2 - purity > 99.7 % Stable oxyfuel operation All emission and safety values contained Interaction between all plant components and subsystems validated Over 50 tests t with Boiler, ASU, CO2 plant and all other components Plant availability very high Integration of a "cold DeNOx" 4 different burners tested New tail end concepts commissioned with good results 65 Lars Strömberg, IEAGHG OCC2 Australia

66 Boiler and Burner Till now three burners tested (Jet-/spin-, pure spin burner) Igniting burner in main burner integrates Variable spinn during operation necessary Results: Good ignition behavior High flame stability Emission values are kept for certain Alstom-Burner Typ A and Typ B 1 Oxidantquerschnitt 1 3 Oxidantquerschnitt Drall Drall Drall Oxidantquerschnitt 3 Stauring Staub- / Fördergas- Querschnitt HPE DS -T Burner 6 Kernoxidant Querschnitt Quelle: ALSTOM 66 2OCC, U.Burchhardt

67 Boiler (furnace) - Temperature Comparison (Front View) Oxy 24% Oxy 28% Oxy 32% Oxy 36% Air (21%) The gas temperatures increases with increased O2 in oxidant as expected The temperature levels for air case corresponds to OXY OCC, U.Burchhardt

68 30 MW th Oxy-Combustion Pilot Plant Burner Design Type A and B Burner Type A Burner Type B Oxy-Combustion Testing in 30MWth Pilot Plant Schwarze Pumpe - IEA-OCC2 Yeppoon, Australia - Frank Kluger - 14 Sep P 68 ALSTOM All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

69 DST Burner for indirect firing Hours installed: Oxyfuel operation: Air operation: h (19 th of April 16 th of June) h h 2nd International Oxyfuel Combustion Conference, 12th-16th September 2011, Yeppoon, Australia Hitachi Power Europe GmbH 69

70 DST burner 2nd International Oxyfuel Combustion Conference, 12th-16th September 2011, Yeppoon, Australia Hitachi Power Europe GmbH 70

71 Premixed / hybrid mode Premixed mode DST burner Hybrid mode DST burner M M M M M M Flue gas Flue gas + O 2 Flue gas M O 2 O 2 O 2 M O 2 M 2nd International Oxyfuel Combustion Conference, 12th-16th September 2011, Yeppoon, Australia Hitachi Power Europe GmbH 71

72 Oxyfuel operation - Oxyfuel flame example Heat input: 27 MW th O 2 in oxydant: 32 % by vol. (wet) NO x : 416 mg/m³ = kg/mwh 2nd International Oxyfuel Combustion Conference, 12th-16th September 2011, Yeppoon, Australia Hitachi Power Europe GmbH 72

73 CS Energy/IHI Burner Testing Programme at Callide A Power Stationti Callide A Project would be the world s 1 st oxyfuel retrofitted power station. First oxyfuel pilot plant that will actually produce electricity. Installation ti of 2 new Wall Fired Burners A unique position to provide information related to the burner burner interaction Courtesy of CS Energy, IHI 73 73

74 Thank you Website: 74