Carbon Sequestration: Engineering, Capturing, Storage, Trapping YouTube Lecture Handouts for NET, IAS, State-SET (KSET, WBSET, MPSET, etc.), GATE, CUET, Olympiads etc.
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Carbon Sequestration - Capture, Transport & Storage
Ways to reduce atmospheric carbon
- Reduce emissions
- Store the carbon in terrestrial, oceanic and aquatic ecosystem
CO2 absorbs IR rays, as its concentration increases, average temperature of EarthΥs lower atmosphere rises (global warming)
Sink:
Process that removes GHG from atmosphere
Carbon capture was first used in Texas in 1972 as a method to enhance oil recovery.
Sequestration
Carbon capture and long-term storage of carbon and CO2 to mitigate global warming
Can be natural or anthropogenic
Natural Carbon Sink
Forest
Growth of replacement vegetation on cleared land
Land-management practices that absorb carbon
Ocean
Iron fertilization encourage phytoplankton growth, which removes carbon from the atmosphere for at least a period of time
Fertilize ocean with urea, a nitrogen rich substance, to encourage phytoplankton growth
Seaweed grows very fast and can theoretically be harvested and processed to generate biomethane, via Anaerobic Digestion to generate electricity or as a replacement for natural gas.
Geoengineering
- Carbon Capture & Storage (CCS) β 3-stage process - capture, transport and store - carbon dioxide is first separated from other gases contained in industrial emissions.
- It is then compressed (dense, fluid, supercritical state) and transported to a location that is isolated from the atmosphere for long-term storage.
Three Methods for Capturing and Separating CO2
- Precombustion capture: Before the fuel is burnt, the fuel is converted to syngas, and then the syngas to hydrogen and CO2. Hydrogen is separated from CO2 so the hydrogen can be used as fuel.
- Post-combustion: After the fuel is burnt, CO2 is separated from nitrogen using chemical sorbents such as monoethanolamine.
- Oxyfuel combustion: Burning fuel in pure oxygen so no nitrogen is present in the captured gases
Suitable Storage Locations
- Deep saline formations (sedimentary rocks whose pore spaces are saturated with water containing high concentrations of dissolved salts)
- Depleted oil and gas reservoirs or deep, un-minable coal beds - Geological Sequestration
- Deep ocean - Sub sea floor Sequestration
It can also include use of artificial trees and scrubbing towers
Geologic Sequestration Trapping Mechanisms
- Hydrodynamic Trapping: CO2 can be trapped as a gas under low-permeability cap rock (as natural gas is stored in gas reservoirs) .
- Solubility Trapping: CO2 can be dissolved into a liquid like water or oil.
- Mineral Carbonation: CO2 can react with minerals, fluids, and organic matter in a geologic formation to form stable compounds; largely calcium, iron, and magnesium carbonates.
Reuse
- Paper Filler
- House building material
- Solar Gasoline
Concern: Leakage of carbon from reservoirs but properly managed geological storage is very likely (that is, 66 β 90 percent probability) to retain 99% of its sequestered CO2 for over 1,000 years along with high financial costs.
Carbon sequestration activities have been supported through CDM (Clean Development Mechanism) under Kyoto protocol with a focus on afforestation, reforestation, improved forestry or agricultural practices, and revegetation
β Manishika