Carbon Capture and Storage (CCS) methods

• Carbon Capture and Storage (CCS) is a technology that can capture up to 90% of CO2 emissions from fossil fuels used in electricity generation and industrial processes.
• CCS prevents carbon dioxide from entering the atmosphere.
• The CCS chain consists of:
• Capturing carbon dioxide
• Transporting carbon dioxide
• Securely storing CO2 emissions underground in:
• Depleted oil and gas
• Deep saline formations

Global CO2 Emissions (2015)

• China accounted for 28% of global carbon dioxide emissions from fuel combustion.
• The United States accounted for 15%
• India accounted for 6%
• Russia accounted for 5%
• Japan accounted for 4%

Methods of Carbon Capture

• There are three main techniques
• Pre-combustion:
• Takes place before the fuel is placed in the furnace,
• First converts coal into a clean-burning gas,
• Stripping out the carbon dioxide released by the process.
• Post-combustion process:
• Post-combustion capture (PCC) removes carbon dioxide from the flue gas after the fossil fuel has been burned.
• Oxy-fuel:
• Coal is burned in an atmosphere with a higher concentration of pure oxygen, which results in exhaust gas almost pure carbon dioxide

Transportation

• After capture, carbon dioxide needs to be transported to suitable storage sites.
• Millions of tonnes of carbon dioxide are transported annually for commercial purposes using:
• Pipelines
• Ships
• Road tankers.
• Pipelines are the cheapest transport method.
• Trucks can be used if the storage sites are near.
• Conveyor belt systems or ships can also be utilized for transporting carbon dioxide.

Carbon Dioxide Storage

• Carbon dioxide can be stored in three main forms:
• Deep geological formations
• Deep ocean water (ocean storage)
• Mineral carbonates (mineral storage)
• In deep geological formations Carbon dioxide is stored in carefully selected geological rock formations that are typically located several kilometers below the earth's surface.
• As carbon dioxide is pumped deep underground, it is compressed by the higher pressures and becomes essentially a liquid
• Carbon dioxide is converted into a high pressure liquid-like form known as 'supercritical CO2'.
• Supercritical CO2 behaves like a runny liquid.
• This supercritical carbon dioxide is injected directly into sedimentary rocks
• Rocks used may be in old oil fields, gas fields, or in saline formations.
• Unminable coal seams and saline water-filled basalt volcanic rocks have been suggested as storage sites.
• Deep ocean storage is a proposed form of carbon dioxide storage however:
• Environmental costs are generally believed to be bad
• The process not being well understood
• Large concentrations of CO2 kill ocean organisms as it acts as an asphyxiant.
• CO2 reacts with water to form carbonic acid (H2CO3), raising ocean acidity as a result.
• Mineral storage involves carbon dioxide exothermically reacted with readily available metal oxides.
• Creates stable carbonates (e.g., calcite, magnesite).
• This process occurs naturally over many years and is responsible for a great amount of surface limestone.

Major Storage Sites

• Sleipner, Norwegian North Sea
• Altmark, Germany
• Weyburn, Canada
• In Salah, Algeria
• Miranga, Brazil
• Hontomin, Spain
• Hastings, Texas, USA

Captured Carbon Utilization

• Collected carbon is used to create carbon nanotubes or a low-carbon alternative crude that can be refined for fuel.
• Methods exist to create both methanol and hydrocarbon fuels.
• Carbon Dioxide can be used in oil extraction, where it is pumped into an underground deposit to pressurize it. -Leakage is a concern in storage and sequestering methods.
• Carbon Dioxide is eventually released into the environment in some reuses such as agricultural applications
• Carbon Dioxide can also be converted into biomass, achieved through algae farming using Carbon Dioxide as a feedstock.

Carbon Dioxide Uses

• Food and fuels
• Algae
• Greenhouse gasses
• Flavors/fragrances
• Decaffeination
• Methanol
• Urea
• CO
• Methane
• Plastics
• Fire suppression
• Fire extinguishers
• Refrigeration
• Dry ice
• Miscellaneous
• Injected into metal castings
• Respiratory stimulant (added to medical O2)
• Aerosol can propellant
• Dry ice pellets used for sand blasting
• Red mud carbonation

CCUS Role in Global Climate Action

• CCUS is an key option in global efforts to reduce CO2 emissions.
• Research from the Intergovernmental Panel on Climate Change (IPCC) shows that climate action would be 138% more expensive without carbon capture and storage.
• Industries implementing less polluted environments around them with this technology.
• Implementing this technology for carbon dioxide from industry and combustion can reduce and store carbon dioxide.
• India needs this technology to reduce global warming.
• This technology is new and emerging, implementing this would be a cost but would be worth it.