STUDY ON CO2 EMISSION CONTROL METHODS IN THERMAL POWER PLANT

Prepared by

T. Amarnath

V. Kannan

R. Karthikeyan

V. Manikandan

M. Palaniappan

G. Prasanthraj

S. Vignesh

S. Vigneshwaran

Guided by

Dr.M.Ravichandra Babu

Associate Professor

ABSTRACT

• Thermal Power Plants are one of the main source of Green HouseGases (GHG) emission throughout the world and 1/3rd of the World’sPower generation derived from Coal Combustion

• The increase of green house gas emission is an important and mostconcerned issue significantly CO2 which play major role in reportingof Global Warming.

• This issue to be handled very seriously by providing advancedmethods to removal of CO2 from the exhaust.

• This can be achieved by means of Carbon dioxide Capture andStorage(CCS) Techniques

GREEN HOUSE GASES & EFFECT

• The major Green House Gases(GHG) in atmosphere are

• Carbon di oxide

• Methane

• Nitrous oxide

• Chlorofluorocarbons

• Ozone

• Effects of GHG

• Absorb IR radiation

• Affects ozone layer

• Increasing CO2 content in atmosphere

SOURCES AND EFFECTS OF CO2

Sources• Fossil Fuel combustion (coal,

natural gas, and oil)

• Industry

• Residential and commercial

• Transportation

Effects

• Sea level rise

• Impacts on agriculture

• Depletion of ozone layer

• Increased extreme weather

• Ecosystem change

CO2 CAPTURE & STORAGE

• The three main components of the CCS process:

• Capture

• Transport

• Storage

Methods of CCS

• Fuel Decarbonisation

• Pre Combustion Capture

• Post Combustion Capture

• Oxy Fuel Firing

• CO2 Scrubbing

• Particle Swarm optimisation

• FireFlies Optimisation Technique

FUEL DECARBONISATION

• Decarbonisation means reducing its carbon intensity that is the emissionsper unit of electricity generated

• It comprises

Pre combustion Capture

Post Combustion Capture

PRE COMBUSTION CAPTURE

• Hydrocarbon conversion - conversion of fossil fuel to a mixture containing hydrogen, CO2 and CO

• CO conversion - shifting this mixture to a mixture with CO2 and H2

• CO2 removal - separation of CO2 and hydrogen

POST COMBUSTION CAPTURE

• Instead of flowing directly up the flue stack and into the atmosphere, a slip-stream of the flue gas is cooled and then treated to separate the CO2 at an adjoining capture plant.

• Currently, the most common way to separate the CO2 is to bring it into contact with a liquid solvent, such as an amine or ammonia.

• The CO2 binds to the solvent, thereby removing it from the other gases in the flue gas stream

OXY FUEL FIRING

There are four components of oxy fuel combustion process

• Air separation unit – Provides oxygen for Combustion

• Combustor – Either a boiler or Furnace

• Integrated Emission Controls

• Product Recovery Train(PRT) – Produces a product CO2 Stream

ADVANTAGES OF OXY FUEL FIRING

• The mass and volume of the flue gas are reduced by approximately 75%because the flue gas volume is reduced, less heat is lost in the flue gas

• The size of the flue gas treatment equipment can be reduced by 75%

• The flue gas is primarily CO2, suitable for sequestration

• The concentration of pollutants in the flue gas is higher, making separationeasier

• Most of the flue gases are condensable; this makes compression separationpossible

• Heat of condensation can be captured and reused rather than lost in the fluegas because nitrogen from air is not allowed in, nitrogen oxide production isgreatly reduced

CO2 SCRUBBING

• CO2 scrubbing system is an absorber in which a scrubbing solution takes upthe carbon dioxide from the power plant‘s flue gas at low temperatures

ADVANTAGES OF CO2 SCRUBBING

• A CO2 Scrubber can help protect the economy by diminishing the need to reduce the use of fossil fuels, which remain less expensive than renewable and alternative energy sources.

• Finding ways to reduce carbon in the atmosphere, because most consumers are not willing to reject fossil fuel use

• Using a CO2 scrubber will reduce the amount of green house gases that lead to global Warming

• It is estimated that the amount of carbon in atmosphere is ready 40% higher than between the industrial revolution. So environmentalists argue that Scrubber technique are needed regardless of advances in alternative energy sources.

CO2 SEQUESTRATION

Sequestration means that prevent CO2 from entering the atmosphere. The function of carbon sequestration is to prevent excess carbon dioxide release from the

burning of fossil fuels from entering the atmosphere.

Requirement for sequestration

• Time

• Location

• Cost

• Environmental Impact

• Storage capacity

Sequestration methods

• Mineral sequestration

• Oceanic carbon sequestration

• Terrestrial carbon sequestration

• Geologic carbon sequestration

MINERAL SEQEUSTRATION METHODS

• Mining

• Reacting

• Sequestrating of Carbonates

OCEANIC CARBON SEQUESTRATION

• It involves the storing of carbon in the ocean

• Naturally, carbon stored in ocean by 2 methods

• Solubility method – by natural circulation of water

• Biological method – through food web process by species

• But manually carbon is stored by DIRECT INJECTION in oceans

• Direct injection comprises

• Capture

• Storage

• Transportation

• Injection

INJECTION TECHNIQUES

• Droplet plume – liquid CO2 injected from a manifold below 1000 m, forminga rising plume

• Dense plume – a dense CO2 seawater mix that sinks, injected at a depthbetween 500 and 1000 m

• Dry ice – dropped off a boat and allowed to sink and diffuse

• Towed pipe – injected from a boat at a depth of 1000 m, forming a risingplume

• CO2 lake – injection at a depth of around 4000 m to form a stable ‘‘deep lake’’

CONCLUSION

• There are many carbon capture techniques under development, howevernone are yet operating at the perfect scale in electric power industry.

• From the various studies about Carbon capture, Oxy Fuel Combustion andCO2 Scrubbing are the leading combustion based techniques applied to newunits or retrofit to existing units nowadays.

• Also various sequestration methods are involved in carbon capture and longterm storage of atmospheric co2 are studied.

Thank you