The future challenges for clean coal technologies joining by nur18009

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									  The future challenges for “clean coal
technologies”: joining efficiency increase
     and pollutant emission control

     Alessandro Franco, Ana R. Diaz Vazquez
           Dipartimento di Energetica “L. Poggi”
                  Facoltà di Ingegneria
              Via Diotisalvi, 2 – 56126 PISA
               E-mail: alessandro.franco@ing.unipi.it
                                    Introduction
Worldwide energy and electricity consumption is projected to grow at an average annual
ate of 2-2.5% between now and 2025 caused by increase of population (up to 7.5 billion)
 nd increase of consumption (mainly of China and India)

 oal offers an abundant, widely spread energy resource at quite stable price, from many
nternational suppliers. It will continue to play a significant role in new generating capacity.

                               Contents of the presentation
ntroduction
   Energy demand, energy reserves, generating capacity, technology choices
   The pespective of coal

 he unclean nature of coal

Coal-fired power generation technology options
  PF technology
  fluidised bed combustion systems
  IGCC
  advanced cycles

R,D
    is Coal an opportune pathway for 21st century?
                                                                 2025 (24500 Twh)
 3% of world primary energy
                                   2004 (15000 Twh)
 6% of the world’s electricity                                       Natural Gas
                                       Natural
s produced using coal. Main                           60%               27%
                                         Gas
uel for electricity in USA,              18% Nuclear
                                                     Growth
Germany, China, India, South                    17%                                Nuclear
                                                              Coal                  12%
                                    Coal
Africa, Australia, much of          36%        Renew
                                                              32%
 entral Europe.                                 20%                          Renewables
                                           Oil
                                           9%                                   20%
 0% of the world’s steel is                                            Oil
 roduced using coal                                                    9%




 Negative Perceptions                          • Positive Perceptions
  –Dangerous and Dirty Mines                      –Abundant Supply in U.S. and EU
  –Old Technology                                 –Cheap and stable price
  –CO2, SOx, NOx, and other Pollutants            –New Clean Technologies
  –Smog and Suit                                  –Jobs in Plants and Transportation
  –Poor Working Conditions                        –Politics (R&D for Clean Air Research)
  –Politics (Relaxing Clean Air Standards)
oday problems: new plants, replacement of ageing plants and Normative

               China
 ECD North America                                                     - New power plants for 4800 GW
       OECD Europe
          Other Asia
                                                                       are expected to be built worldwide
ransition economies                                                    over the period 2006-2030.
       OECD Pacific
               Africa
                India
                                               Under construction      - Half of these new power plants
Other Latin America                            Planned                 will be in developing countries and
         Middle East
                                               Additions needed        a lot of them will be based on coal
               Brazil                          by 2030
           Indonesia

                        0   100 200 300 400 500 600 700 800 900
                                                      GW

OECD countries will need nearly                           140
                                                                    Age of Installed Capacity in Europe
2000 GW of new power plants.                              120
More than a third of this new                             100
                                                                       Oil
                                                                       Gas
capacity will be built to replace                                      Coal
                                                         GW


                                                              80       Nuclear
ageing power plants in the region.
                                                              60

More than half Europe's power                                 40
plants could be retired by 2030                               20
                                                              0
                                                          < 10 years       10 - 20     20 - 30     > 30 years
        Coal technology: an historical evolution
                                                       Great technological evolution of PCC based on
ill to the beginning of Sixties (’60)
                                                       Thermodynamic optimization

                                                       Not meaningful efficiency increase, growing
From the beginning of the Sixties
                                                       attention to SOX and NOX emissions for
                                                       Satisfaction of Normative


               Central name               State                         Steam conditions

     Philo N.6                   USA      ‘50                310 bar,    621°C/565°C/538°C
     Eddystone I                 USA      ‘50                345 bar,    649°C/566°C/566°C
     Kashira                     Russia    ‘60               306 bar,    650°C/565°C
     Typical USA coal plants     USA      ‘60                241 bar,    566°C/566°C
     Typical Italian PCC plant   Italy     ‘70               250 bar,    540°C,540°C
     Kawagoe                     Japan     ‘90               311 bar,    566°C/566°C/566°C
     Frimmesdorf                 Germany         ‘90         250 bar,    580°C/600°C
     Averdore 2                  Denmark         ‘90         300 bar,    580°C/600°C
     Torrevaldaliga Nord         Italy       ‘00             250 bar,    600°C/610°C


                                                             Efficiency level 44%
  Actual standard                                            Cost about 1000 USD/kW
                      What makes coal “unclean”?
 •     Coal is mostly carbon      C+O2→CO2
 •     Coal contains sulphur      S+O2→SO2
 •     Coal contains ash      = particulate deposition
 •     Coal contains other materials, (As, Cl, Hg, Ni, Pb)
 •     Combustion produces NOx (Acid Rain, Greenhouse gas, Health effects)

     Italian environmental limits (400/200/50 mg/nm3 for SO2, NOX, Particulates)

 European Directive 2001/80/CE (200/200/30 mg/nm3 for SO2, NOX, Particulates)

     Conventional Coal Power Plant
                                                 NOX emissions from PCC Plant
                       Sub-critical Units            Vado Ligure (ex Enel)
                   Conventional Sulfur control

ficiency                    36-40%
atus                      Established

mission      CO2            850-1000
g/MWh)       NOx             0.5-1.5
             SO2             0.5-0.7              200 mg/Nm3 ~ 0.25 kg/MWh
             PM                0.1
          What means “Clean coal technologies”?
 mission Control not modifying the PCC concept (Reduce SOX ,NOX PM & CO2)
   1. Precombustion burning: cleaning of coal

   2. Combustion-enhancing technologies (e.g. Oxyfuel combustion)

   3. Post-combustion cleaning

   4. Increase the efficiency of coal conversion


Advanced conversion technologies modifying the PCC concept
   1. Steam Parameters To Ultra Supercritical Parameters (USC)

   2. Fluidized Bed Combustion (FBC)

   3. Indirect combustion through coal gasification (IGCC)



CO2 Capture Technologies
 re-Combustion (Separation of CO2 from the fossil fuel)

 ost-Combustion (Removal of CO2 from combustion flue gases)

 xy-Fuel Combustion (Combustion with pure O2 and Recycled Flue Gas to reduce CO2
                       Pollutant emission control
Developed and technically available today! Difficulty in maintaining operating standards

                                 NOx control options
             Control Technique               NO Reduction Potential(%)
 Overfire air (OFA)                                     20-30
 Low Nox Burners (LNB)                                  35-55
 LNB + OFA                                              40-60
 Reburn                                                 50-60
 SNCR (Selective non Catalitic Reduction)               30-60
 SCR (Selective Catalitic Reduction)                    75-85
 LNB with SCR                                           50-80
 LNB with OFA and SCR                                   85-95
                                                                                SCR or DeNox

                                       SOx reduction
 Pre combustion removal        - Physical cleaning (30-50% removal inorganic sulfur)
                               - Chemical and biological cleaning (90% removal organic sulfur)
 Combustion configuration

 Post-combustion removal       - Wet Flue Gas Desulfurization (FGD) (80-98%)

 In situ sulfur capture:       - Dry Sorbent Injection (DSI) (50%)
                 PM controls (Mainly post-combustion methods)
  Electrostatic precipitator (ESP)   99% (for 0.1>d(µm)>10)         99% (for 0.1<d (µm)<10)
  Filters (or baghouse)              As high as 99.9%
  Wet scrubber                       95-99%
  Cyclone                            90-95% (d(µm)>10)

  Mercury control                       by using sorbents (is an emerging technology!)

By the available methods and the synergistic effect a good emission control is possible
                                                       360 ℃             150 ℃       125 ℃

                                              Boiler
                                                                                      Dry
                                                       SCR     AH         ESP
                                                                                     DeSOx


                                                                                               Stack




                                         Leonardo Arrighi e Nicola Bracaloni “FROM OLD OIL TO CLEAN
 Enel Torrevaldaliga Nord power plant    COAL: TRANSFORMING TORREVALDALIGA NORD"” in Modern
                Advanced technological options
New requirements to limit emissions to air, land and water impose a technological jum
Today’s technology offers coal a role in future electricity production


                                        Coal

             Combustion                                       Gasification

       Pulverised
                                   Fluid beds
          fuel

       Atm      Press.         Atmospheric           Pressurised

EFCC     USC      PCC          FBC        CFBC         P-CFBC        PFBC       IGCC



  Gas            Steam cycle                            Hybrid/combined
 cycle                                                       cycle
                  Ultra Super Critical (USC) Plants
USC technology is well known: according to Peter Luby (“SUPERCRITICAL
SYSTEMS”, in Modern Power Systems, agosto 2003, pp. 27-32) over 550 super
critical PCC are available all over the world (about 150 in USA, over 100 in Japan and
Russia, more than 30 in Germany for an amount of 300 GW.


•   Using Ultra-Supercritical steam conditions (>300 bar, >620°C), the efficiency of
    PF stations rises still further.

•   Ambitious program (THERMIE AD 700) are being developed to take steam
    temperatures up to 700°C, whence 50 – 52% efficiency is predicted

             Today                        2010-2015
       600 MW reference design              Thermie AD700
          300 bar, 600°/620°C            325 bar, 700°C/700°C
    Achievable η= 45÷47% (Net, LHV)      η= 50÷55% (Net, LHV)




                                                                Research on Advanced
                                                                Materials and Advanced
                                      Pressurized Fluidized Bed
  Fluidization means that the solid coal particles are supported and mixed with air
  which is injected into the system

                            Hot flue gas

                                               Sulphur                                 Burning occurs at 760-930°C, we

                                Carbonizer
                                 Gasifier
                                               sorbent                                 below the 1370°C needed to
                 Clean Up




nergy                                          Coal                                    generate nitrogen oxide pollutants
                   Gas




                                                         PFBC    Steam     Energy
equired                                        Air                         Output
                                                                      ST
          Ash                 Char                                                     SO2 captured by limestone
                                 Char
                                                                                       injection
                                         Air                    ash
                 Topping
                Combustor                                                              CO2 controlled by sorbents
                                                                               stack
                                                           HRSG                        Resulting flue gas can be used in
                    GT           Energy                                                turbines (hybrid cycle)
    C
                                 Output

     Air


  Atmospheric circulating fluidized bed (CFB)                                              The interest was related to the
                                                                                           perspective of using low quality
                                                                                           coal (lignite or brown coal)
  Pressurized Fluidized Bed Combustion (PFBC)
                                            “State-of-the-art” CFBC technology
                                            (data from A. Minchener - EC POWERCLEAN Thematic Network)
                               600
Gross electrical output, MWe




                                                                                                                           Sub critical
                               500                                                                Lagisza (PL)
                                                                                                                           max: 170 bar, 565°/580°
                                                                   Jacksonville (USA)
                                                                                                                           η < 40%
                               400                           AES              Seward (USA)         Sulcis (I)
                                     Gardanne (F)         Puerto Rico                                                      Supercritical
                                                                                                        Baima (China)
                                                    Turow (PL)
                               300                                                                                         260 bar, 560°/580°C
                                                                                   Turow (PL)       Gilbert (USA)
                                                                                                                           η ~ 43%
                                                                                Red Hills (USA)
                               200        Tonghae
                                          (Korea)
                                                    Tha Toom               Can (Turkey)
                               100                  (Thailand)


                                0
                                1994       1996       1998       2000    2002       2004      2006        2008      2010

                                                             Year plant commissioned


No great results with respect to USC:                                                     - the efficiency level is low
                                                                                          - the emission control of NOx and SOX is
                                                                                            similar to that obtained with available treatmen
                                                                                          - no flexibility, problems with plant stop
        Integrated Gasifier Combined Cycle (IGCC)
 ince twenty years ago Integrated
Gasifier Combined Cycles (IGCC) are
 onsidered the future of coal
 ombustion
Notwithstanding some successful
 xperiments, the low number of
 perating plants showed a lot of
 roblems, mostly concerning the
 vailability


n the meantime the renewed interest in the conventional PCC power plants made quite
ess attractive investiments on IGCC


 ut IGCC become a solution of interest for petrolchemical industry


                      IGCC vs. conventional coal plants
           An IGCC places the chemical plant in the front end of plant.
        A conventional coal plant places a chemical plant at the back end,
       attempting to capture pollutants after combustion and much dilution.
                           “Traditional” IGCC
    Coal                              Sulfur, PM
                  Syngas
                 H2 and CO                                          Central Power
   Coal                                   Gas                        Gas Turbine
  Gasifier                              Cleanup                       Combined
                                                                        Cycle
        O2
                  • More than 120 plants with more than 380 Gasifiers in operation in 2004.
                    The facilities produce mostly chemicals (37%), gas (36%) or power (19%)
     O2
    Plant         • Multiple Gasification process technologies
                     – Entrained flow (Shell, GE (Texaco), Conoco-Phillips (Dow/Destec))
                     – Fixed bed (BGL, Lurgi, EPIC)- Dakota Gasification Corp
                     – Fluidized bed (Southern Co- Staunton, KRW)

Barriers to Deployment of IGCC

 . Power Industry Culture. This is a chemical plant. Power companies does not
   like chemical units.
 . Perceived technical and financial risk.
                   Existing Coal-based IGCCs




300 MW Puertollano (Spain)               300 MW Wabash (Indiana)
Emissions (mg/Nm3 @ 6% O2)   NOx = 150
A Reference Plant            SO2 = 25
                             Dust = 8
                        Commercial IGCC Projects
                                                                                      Availability
   Project – Location             Start-Up   MW       Products - Feedstock
                                                                                        hours
Bugghenum – The Netherlands         1994     250   Power / Coal                        6000-8000
Wabash (Global/Cinergy) – USA       1995     260   Repower / Coal, Pet Coke            Max 6000
Tampa Electric Company – USA        1996     250   Power / Coal, Petroleum Coke         < 8000
Puertollano – Spain                 1998     320   Power / Coal, Coke                   > 5000
Pinon Pine - USA                    1998     107   Power / Coal                         < 1000
SUV – Czech Republic                1996     350   Cogeneration / Coal
Schwarze Pumpe – Germany            1996      40   Power & Methanol / Lignite
Shell Pernis – Netherlands          1997     120   Cogen & H2 / Visbreaker Tar
ISAB: ERG/Mission – Italy           2000     510   Power / Asphalt
Sarlux: Saras – Italy               2001     545   Power, Steam, H2/ Visbreaker Tar     > 8000
Exxon Chemical – Singapore          2001     160   Cogeneration / Ethylene Tar
API Energia – Italy                 2001     280   Power & Steam / Visbreaker Tar
Motiva LLC – Delaware, USA          2002     160   Repower / Pet Coke
Nippon Refining – Japan             2003     342   Power / Asphalt



  Efficiency levels                  η =35-42 %
                                                          Some interesting success but low
                                                                     Interest!
  Costs                      below 1400 USD/kW
                                         How clean is “Clean”?
g/m3                                                                          mg/m3
2500                                                                          700
                                                     PF                                                                     PF
                                                     PF+FGD                    600                                          PF+FGD
2000
                                                     SCPF                      500                                          SCPF
                                                     CFBC                                                                   CFBC
1500                                                 IGCC                      400
                                                                                                                            IGCC
                                                     NGCCGT                    300                                          NGCGT
1000
                                                                               200
 500
                                                                               100

     0                                                                            0
                                SO2                                                                         NOx

         gram CO2 / kWh
00                                                                                        1000   Emission factor from coal (EFc
00                                                                                        900

00                                                                                        800

00                                                                                        700

00                                                                                        600

00                                                                                        500    CR = Conversion rate of electricity
00                                                                                        400    HVc = Heating value (12-30 MJ/kg)
00                                                                                        300
                                                                                                 CCc = Carbon content of coal (60-90
          The problem of CO2 mitigation remain!                                                  CE = Combustion efficiency (0.9-0.9
00                                                                                        200
         Coal (C) emits at least the double of CH4
00                                                                                        100

 0                                                                                        0       (EFc) is 0.3-0.4 kgCO2/kWht
     conventional
         coal
                    super
                     critical
                                ultra     super pres
                                    critical
                                                     uris
                                                      ed
                                                         ed
                                               fluidis bed
                                                               integrated
                                                               gasification
                                                                              combined
                                                                              cycle gas
                                                                                                    750-1000 kgCO2/kWhel
                                                combus  tion    combined       turbine
                         CO2 mitigation technologies
echnology that could allow coal use to expand in a greenhouse gas constrained world
                       N2, H2O to atmosphere



                       CO2         CO2                Storage

          Flue
                     Separation
                                   Compression
                                                                          Post-Combustion
          gases
                                                                       Removal of CO2 from combustion flue gase
   Fossil fuel          Power
  combustion          Generation


                                                                                        CO2 or H2O


                                                                                                                    CO2
                                                                         Fossil fuel        Power
        Oxy-Fuel Combustion                                             combustion        Generation   Separation         Storag


 Combustion with pure O2 and Recycled                                          O2

   Flue Gas to reduce CO2 emissions                                    Air Separation
                                                                            Unit



 Coal                                                  CO2
        Gasifier       Shift               CO2
                                                             Storage
                      Reactor            Separation

             O2
                             N2                   H2
                                                                                Pre-Combustion
    Air Separation                                                         Separation of CO2 from the fossil fuel.
         Unit
                                          GT CC
                                                          60                               Without
  0.8
                                                                                           capture
  0.7                                                     50
                                                                                           With
  0.6                                                                                      capture
                                                          40
  0.5
  0.4                                                     30

  0.3                                                     20
  0.2
                                                          10
  0.1
   0                                                       0
                                                               Gas combined   Pulverised coal
         Natural Gas           Pulverised
                                                                   cycle
         Comb. Cycle           Coal plant

  CO2 Emissions Reduction is payed with Power Generation Efficiency reduction

              Author                  Foster            Texaco          Lozza, Chiesa
                                      Capture           Capture            Capture
                                  Without    With   Without    With    Without    With
             Efficiency             38.0 / 31.5       42.1 / 34.3        38.0 / 31.5
        Investment cost €/kW        1187 /1495        1164 /1511         1647 /2364




The CO2 capture energy requirements of different analyzed sorbents (MEA, MDEA,
Na2CO3, K2CO3, NH3(g), Ca0) range between 2 and 6 MJ/kg CO2 produced.

                       Ana R. Diaz, CO2 CAPTURE FOR POWER PLANTS: AN ANALYSIS OF THE ENERGETIC
                       REQUIREMENTS BY CHEMICAL ABSORPTION, ESDA2006 8th Biennial ASME Conference on
                                 R/D lines
New and advanced technologies for pollutant control (SOX, NOX, PM, etc)
       - more economic and ecocompatible than the actually available

Analysis on mercury formation during combustion and during the evolution
of the treatments


New materials for USC plants

Advanced diagnostics for USC plants


IGCC Plants with CO2 capture and separation

Plants “zero liquid discharge”


Evaluation of Proof of Concept of EFCC Technology
                                    IGCC in Future Gen
   Feeds            Gasification                Gas Refining                          End-products
Current IGCC power technology applications focus on producing CO rich
syngas that can be burned in turbines.
                                                                              Combustion Turbine
Future IGCC technologies maybe developed to produce hydrogen rich syngas
with maximum carbon capture (aka “zero emission” IGCC).

Oxygen                                                                                             Electricity

                                                                                         HRSG        Steam


                                                                      Syngas                        Chemicals

                                                                                                    Hydrogen
                                                   MERCURY      SULFUR /CO2

                                     Syngas        REMOVAL        REMOVAL
                                                                                                    Ammonia
                                                                                       Syngas
     Coal                                                                                            Methanol
                                                                       H S
                                                                        2


                                                                           SULFUR
                                                                           RECOVERY



                                                                                                      Sulfur


                           Solids                  Mercury       CO2 Sequestration Option
                 Further objectives of the research

•Search of STRATEGIES ot energy policy accounting the different contributions to the
energy conversion systems; the thermodynamic performance, the environmental impact
and the economic dimension

•An still open question is the definition of the technological limit and of the best compromise
between size of the plant, efficiency and pollution control limits and waste materials to be
pursued in on open sistem perspective .




                                  Sistema di                   Electric enegy
                                  conversione                      Wout
                                  energetica


        Chemical energy
                                                                      Waste enrgy and pollution
         Ein = mf Hf
                                                                          Itot = I   TH
                                                                                          +I   CH
                            Conclusions
EMISSION CONTROL STRATEGIES
 -Good success in controlling PM, NOX and SOX emission, but difficulties for th
    maintainment of standards during operating life of the plant.
 - High sensitivity to the type of coal used
 - Problems with auxiliary material (Ammonia, Urea, Limestone, Gypsum)

ADVANCED TECHNOLOGIES
. Superiority of USC solution in a mid-term scenario

. No convenience in further development of Fluidized Bed
  To much problems during operation and no great advantages

. Interest in development of IGCC solutions in long-term perspective
  - Inherently cleaner process because Coal is not combusted. Pollutants are
  removed with greater efficiency


 CO2 CAPTURE AND STORAGE

								
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