Advances in Lime-Limestone CO2 capture by wbf21256

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									Attrition Free Reactivation of Lime via Hydration
1st meeting of High Temperature Solid Looping Cycles Network , Oviedo, España.
September 16, 2009


Vlatko Materic ; Robert Holt
 Lime-Limestone Cycle For CO2 Capture

                        Heat
              CaCO3

Diluted                  Concentrated
 CO2                         CO2

    Heat
              CaO               CaSO4 + other
                               solid pollutants
    The Oxy-Fuel / Lime Combination




Abanades et al, Environ. Sci. Technol. (2007), 41, 5523-5527
                   Main Process Issue – Lime Deactivation
                                           T G 2 1 C a C O 3 - 7 c y c le s
                1 2 .9                                                                                               1000
                                                                                            mg
                                                                                            T em p                   900
                1 1 .9                                                                      G a s sw it c h p o in t
                                                                                            CO2                      800
                1 0 .9                                                                      N2
                                                                                                                     700




                                                                                                                        T em p era tu re ( )
                                                                                                                                         C
                                                                                                                        o
W eigh t (m g




                 9 .9
                                                                                                                  600

                 8 .9                                                                                             500

                                                                                                                  400
                 7 .9
                                                                                                                  300
                 6 .9
                                                                                                                  200
                 5 .9
                                                                                                                  100

                 4 .9                                                                                             0
                     0 .0 0   1 0 0 .0 0      2 0 0 .0 0          3 0 0 .0 0   4 0 0 .0 0      5 0 0 .0 0
                                                           Tim e ( m in )
Is Hydration a Solution?
Hydration Weakens Particles – Not practical




   17 cycles no hydration   7 cycles with hydration
IRL’s Breakthrough -
Hydration without Attrition
• IRL has discovered a process for reactivating lime
  particles without weakening them.

• A Patent Application has been filed.

• This process is simple and is based on a phenomenon
  dubbed Superheated Dehydration
      Fluid Bed Test Reactor
                   Filter

                                     RH   MFM

           T




               T            P
MFC
                                dP
CO2
                            T
MFC      Water
 N2      Pump
    Standard Hydration Induces Attrition

                                                               Standard Hydration
                                                       Hydrated                 Hydrated
                          No Reactivation         every Calcination        every 3 Calcinations
                       (48 calcinations total)   (8 calcinations total)   (48 calcinations total)

  Average Activity             22%                      ≈60%                      34%

  Fines < 150 um               4.8%                    10.8%                      8.9%

Cycles to 100% fines           1000                       75                       537
  Superheated Dehydration
  40.0                                                                             650
  35.0
                 H2O out
                 Bed Temperature                                                   600
                                                                                         Dehydration in N2 :
  30.0
                                                                                   550
  25.0
                                                                                   500
                                                                                         Normal Dehydration
kPa




  20.0
                                                                                   450
  15.0
  10.0
                                                                                   400
                                                                                         Water Released at
      5.0                                                                          350         440 C
      0.0                                                                          300
            35              40        45        50        55        60        65




  40.0                                                                             800
                 H2O out
  35.0
                 Bed Temperature
                                                                                   750
                                                                                   700
                                                                                         Dehydration in CO2:
  30.0
                                                                                   650
  25.0                                                                             600
                                                                                         Superheat Dehydrat.
kPa




  20.0                                                                             550
  15.0                                                                             500

  10.0
                                                                                   450    Water Released at
                                                                                   400
      5.0                                                                          350         610 C
      0.0                                                                          300
            35                   45        55        65        75        85
        Superheated Dehydration Improvement
                                 Standard Hydration                             Superheated Dehydration
                             Hydrated                 Hydrated                  Hydrated                  Improved
                        Every Calcination       Every 3 Calcinations      Every 3 Calcinations      Every 3 Calcinations
                       (8 calcinations total)   (29 calcinations total)   (29 calcinations total)   (29 calcinations total)


  Average Activity           ≈60%                       36%                       42%                       61%

  Fines < 150 um             10.8%                    7.45%                      5.1%                      3.5%

Cycles to 100% fines            75                      389                       568                       829
Particle Growth in Extreme SD Annealing

                        Extreme annealing Experiment
                        -SD Hold at 540C for 100 min
                        -Material volume increased 2.5x
                        -After 24 calcinations-0.61% fines
                        - 45% particles > initial size
Reactivation Cycle – Optimal setup
                            Spent CaO


              Hydration              Heat
 H2O / Gas                      (to steam cycle)
               300°C



              Annealing             CO2
CO2
               500°C             (recycle)


              Dehydration
Air + CO2          +            Reactivated
              Carbonation         CaCO3
(Flue gas?)
                 620°C


                    H2O / Gas
             Proposed Overall Process
                                            Active
                                            CaCO3
                                                       IRL’s
                                             Spent Reactivator
                                             CaO     400C




Amended from Abanades et al., Environ. Sci. Technol. (2005) 39, 2861-2866
IRL’s Model Calculations
• IRL has developed a Heat and Mass balance model of
  the overall process

• Performance is consistent with results of Abanades
  model and includes the operation of the reactivator

• Preliminary costing results from model indicate costs
  in the $11-$18 t/CO2 for oxyfuel/lime combination
Further Plans
• Ongoing research
          – Understanding the chemistry of the SD phernomenon
          – Further improvements to resulting activity


• IRL intends to demonstrate the performance of the
  reactivator in tandem with a continuous circulating
  Carbonation/Calcination system at a small scale.

• IRL is seeking partners with experience in circulating
  lime-limestone systems to jointly demonstrate the
  overall process

								
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