1. SHRI RAMDEOBABA COLLEGE OF
ENGINEERING AND MANAGEMENT
TECHNICAL SEMINAR
TOPIC: OXYGEN CARRIERS USED IN CHEMICAL LOOPING COMBUSTION.
Seminar guide: S.A. PATIL SIR
PRESENTED BY:
AVADHESH BAGDI
ROLL NO.30
2. NEED OF CO2 CAPTURE
• Emission of Greenhouse gases is the main contributor to the
Global warming.
• The life of C02 obtained from fossil fuels is estimated to be 300
years and moreover 25% lasts forever.
• Global concentration of CO2 has increased from 280 ppm to 390
ppm as of 2010.
• Change in CO2 level by 15% may increase the global temperature
by 2˚c
• The European union has committed to reduce the CO2 emission
by 20% by 2020.
3. CO2 CAPTURE TECHNOLOGIS
• For CO2 capture at fossil fuel energy plants, there are four options
available for CCS (carbon capture and storage) –
1. Post combustion capture
2. Oxy- fuel combustion
3. Pre- combustion decarbonisation.
4. Chemical looping combustion.
4. CHEMICAL LOOPING COMBUSTION (CLC)
• The first idea of chemical looping combustion was found in 1954 and
in 1980 chemical looping was introduced as technology for
combustion and CO2 capture.
• CLC is the prominent CO2 capture processes in which metal oxides are
used as oxygen carriers.
• CLC process is carried out at 600˚c to 1200˚c.
• There are two interconnected fluidized bed reactors
1. Air reactor
2. Fuel reactor
6. • The fluidized bed are generally of quartz sand.
• Gaseous fuel is fed into the fuel reactor and is oxidized with metal
oxide. The fuel is combusted resulting into elimination of CO2 and
H2O.
• Water is condensed resulting into CO2 separation. Separated CO2 is
stored in tanks.
• Reduced metal oxide is then fed back into air reactor where it is
reoxidised and again fed into fuel reactor. N2 and O2 are eliminated
from air reactor.
• Nickel, copper, cobalt, iron and manganese are good oxygen carriers
used in CLC.
• CLC does not bring any enthalpy gain.
7. Here High velocity riser and low velocity
bubbling fluidized bed are considered as air
and fuel reactor.
Particles leaving the air reactor are sent to
the fuel reactor by cyclone. The fuel reactor
particles are mainly circulated by gravity so
reactor has to be placed at a specific height.
In air reactor, the volumetric flow is 10 times
greater than the fuel reactor. So high velocity
is maintained in air reactor necessary to
provide the required driving force to
circulate particles.
8. The overall reactions can be written as:
IN FUEL REACTOR:
(2n+m)MyOx + CnH2m → (2n+m) MyOx-1 + mH2O + nCO2
IN AIR REACTOR:
MyOx-1 + ½ O2 → MyOx
9. OXYGEN CARRIERS
• The selection oxygen carriers is one of the most important aspects in
CLC.
• Oxygen carriers should posses following main properties:
a. Be stable under continuous oxidation and reduction.
b. Be fluidizable.
c. Be resistant to agglomeration.
d. Be mechanical resistant to friction.
e. Be environmental friendly and be economically feasible.
10. • Some another important aspects are:
a) Melting point of oxygen carriers.
b) Complete conversion of fuel.
c) Density, active surface area, pore volume, particle size, crushing
strength are also considered.
d) Reactivity and durability.
11. • CO3O4 offers highest amount of oxygen per mole of metal.
But NiO is considered more favorable due to its other properties.
Fe2O3 has least oxygen carrying capacity but it can convert almost all the fuel into
carbon dioxide and has highest melting point amongst all the favourable metal
oxides.
12. • There are mainly four types of oxygen carriers currently under study.
They are :
a) Ni-based oxygen carrier.
b) Fe-based oxygen carrier.
c) Cu-based oxygen carrier.
d) Mixed-oxide oxygen carrier.
