Absorption of Carbon Dioxide by a Suspension of Activated by steepslope9876

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									   Absorption of Carbon Dioxide by a
   Suspension of Activated Carbon in
       Aqueous Amine Solutions

                             Yahia Alhamed

                        King Abdulaziz University
                          Faculty of engineering
             Department of Chemical and Materials Engineering,




Dr. Y. Alhamed KAU          CHEMINDIX2007 Manama
Jeddah Saudi Arabia         Bahrain 26 - 29 April 2007           1
 Introduction
                                Main features of CO2



• As a feed
   – Chemical industries (e.g. urea production)
   – Food and beverage carbonation.

• As an impurity
   – Natural gas processing
   – Ammonia synthesis

• As a pollutant

 Dr. Y. Alhamed KAU       CHEMINDIX2007 Manama
 Jeddah Saudi Arabia      Bahrain 26 - 29 April 2007   2
 CO2 Removal Using Amines
     MEA and DEA are widely used in industry.
     TEA is less used due to its lower capacity,
      higher cost, and lower reactivity.
     The capacity of 1ry amines is limited to  0.5
      mole CO2/mole amine.
     Any increase in the absorption capacities of
      these systems for CO2 will definitely improve
      the economics of these processes.


Dr. Y. Alhamed KAU    CHEMINDIX2007 Manama
Jeddah Saudi Arabia   Bahrain 26 - 29 April 2007   3
  Previous Studies (Achievements)
• Significant enhancement of CO2 absorption rate into
  water-activated carbon (AC) slurries.

• The feasibility of using immobilized 1ry amine in
  place of homogeneous additives to enhance CO2 in
  3ry amine solutions.

• Use activated carbon (AC) as a solid activator.
  – Higher rate of absorption of CO2.
  – Unknown absorption capacity in the presence of
    AC.
Dr. Y. Alhamed KAU    CHEMINDIX2007 Manama
Jeddah Saudi Arabia   Bahrain 26 - 29 April 2007    4
Objectives

• Study the effect of AC (activator) on the
  absorption capacities of CO2 in a suspension of
  AC - aq. amine solution.

• Study the effect of amine type, amine
  concentration and AC loading on the adsorption
  capacities.


Dr. Y. Alhamed KAU    CHEMINDIX2007 Manama
Jeddah Saudi Arabia   Bahrain 26 - 29 April 2007   5
Experimental


                                               To soap film meter
                               CO2 Mass flow controller
                                                                To GC for analysis
                                            F
                Dryer                                   V1

                                               F                    Bubble column
                                      N2 Mass flow controller V2

                           Dryer


                 CO2 Cylinder                                      V3 -
                                           To soap film meter

                                                     To GC for analysis

                        N2 Cylinder



Dr. Y. Alhamed KAU                    CHEMINDIX2007 Manama                           6
Jeddah Saudi Arabia                   Bahrain 26 - 29 April 2007
Breakthrough curves of CO2
250 ml of 0.05 mol/l MEA, CO2 = 0.2, at 250 ml (STP)/min,


                                                     50
                  absorption column (ml(STP)/min.)
                     flow rate of CO2 leaving the

                                                     40

                                                     30                                    Cc   = 0 g/l
                                                                                           Cc   =5 g/l
                                                     20                                    Cc   = 10 g/l
                                                                                           Cc   =30 g/l
                                                     10                                    Cc   =50 g/l
                                                                                           Cc   =100 g/l
                                                      0
                                                          0         10               20         30         40
                                                                             Time (min.)

  Dr. Y. Alhamed KAU                                          CHEMINDIX2007 Manama
  Jeddah Saudi Arabia                                         Bahrain 26 - 29 April 2007                        7
Effect of AC loading on CO2 absorption capacity


 R is defined as:
                       CO 2 absorbed by amine(aq) AC
                                                 
                         CO 2 absorbed by amine(aq)


R > 1  increase absorption capacity due to AC
        addition.


 Dr. Y. Alhamed KAU         CHEMINDIX2007 Manama
 Jeddah Saudi Arabia        Bahrain 26 - 29 April 2007   8
 Effect of AC loading on R for DEA solution
YCO2 = 0.4; total feed rate = 150 ml (STP)/min.
                                     CA = 0.0 mol/l             CA = 0.05 mol/l
                      4.5            CA = 0.1 mol/l             CA = 0.3 mol/l


                      3.5
                 R




                      2.5


                      1.5


                      0.5
                            0      10                  20         30             40
                                        AC loading (g/l)


    Dr. Y. Alhamed KAU             CHEMINDIX2007 Manama
    Jeddah Saudi Arabia            Bahrain 26 - 29 April 2007                         9
R versus AC loading for MEA concentration

                 4.5


                 3.5


                 2.5
             R




                                             CA = 0.05 mol/l

                 1.5


                 0.5
                       0   20      40      60      80          100   120
                                  AC loading (g/l)


 Dr. Y. Alhamed KAU             CHEMINDIX2007 Manama
 Jeddah Saudi Arabia            Bahrain 26 - 29 April 2007                 10
R vs AC loading at various concentrations of TEA.


                           1.4

                           1.3

                           1.2

                           1.1

                           1.0
                       R




                           0.9

                                                                 CA = 0.01 mol/l
                           0.8
                                                                 CA = 0.05 mol/l
                                                                 CA = 0.1 mol/l
                           0.7
                                                                 CA = 0.2 mol/l
                           0.6

                           0.5
                                 0   20            40             60               80   100
                                              AC loading (g/l)



 Dr. Y. Alhamed KAU                       CHEMINDIX2007 Manama
 Jeddah Saudi Arabia                      Bahrain 26 - 29 April 2007                          11
Conclusions

• Adding AC to amine solutions is beneficial.

• Addition of AC (activator) allows the use of
  lower amine concentrations while keeping the
  same absorption capacity.

• This is more beneficial in case of MEA
  (corrosive than DEA) at concentrations > 20%

Dr. Y. Alhamed KAU    CHEMINDIX2007 Manama
Jeddah Saudi Arabia   Bahrain 26 - 29 April 2007   12
Further work
    Effect of :-
    • AC particle size,
    • Temperature,
    • flow rate and composition of the gas,
     Adsorption studies of amines by AC are very
      important to explain the results obtained.




Dr. Y. Alhamed KAU    CHEMINDIX2007 Manama
Jeddah Saudi Arabia   Bahrain 26 - 29 April 2007   13
• Thank you very much for your attension




Dr. Y. Alhamed KAU    CHEMINDIX2007 Manama
Jeddah Saudi Arabia   Bahrain 26 - 29 April 2007   14

								
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