Carbon Capture and Utilization (CCU) MINE PORTAL TEAM www.MINEPORTAL.in CALL/WHATSAPP-8804777500 www.fb.com/mineportal.in

INDEX: Earth’s Carbon reserve What is the need for carbon capture ? What are Carbon sources and Carbon sinks ? Different technologies to isolate CO2 from flue gases. Methods for Capturing CO2 Transportation of CO2 Carbon storage Limitations Ways for Carbon Utilization. Case study Conclusion Reference

Earth's Carbon Resources Since last decade, average conc. of CO2 increasing by 1.5 ppm per year. The oceans holds the greatest part but is held effectively out of circulation in the form of dissolved bicarbonate. 80% of fossil fuel carbon is in the form of coal and it’s burning releases carbon directly to the air in the form of CO2 * This table showing the sizes of the various carbon reservoirs is from U.S. Global Change Research Information Office

Effects of Carbon Dioxide in Air

Emit more carbon dioxide than they absorb Carbon Sources Carbon Sink Emit more carbon dioxide than they absorb Absorb more carbon dioxide from the atmosphere than they emit Natural sources : Volcanoes Fires Decomposition Respiration Sometime Oceans and fresh water bodies. Natural sinks : Photosynthesis Forests Oceans Freshwater bodies Fossil fuels Carbonate rocks. Human Interference Deforestation and Fossil burning Reduction in size of the sink More Carbon in Atmosphere.

Carbon sources and sinks

Isolation of CO2 from other gases Carbon Capture Definition: Technique that prevents or reverses the release of Carbon dioxide to the atmosphere and diverts the carbon to a viable carbon sink. # Isolation of CO2 because of constraint of additional cost associated with transportation ,compression and additional storage space. Isolation of CO2 from other gases Compression Transportation

Sources for Capture Global CO2 emissions from fossil fuels in 10^(15) g CO2 / year => Electricity generation and some large fossil fuel burning industrial sources are good candidates for carbon capture. * Stanford university-GCEP Carbon Capture Technology Assessment – Spring 2005

Principle: CO2 in the gas phase dissolves into a solution of water and amine compounds. Procedure: Flue gas first cooled and treated to remove reactive impurities such as sulphur, nitrogen oxides, and particulate matter. The amines react with CO2 to form protonated amine (AH+) and bicarbonate (HCO3-). After CO2 loading, solution removed and heated to release high-purity CO2. Technologies that help accomplish carbon isolation. A . Using Chemical Solvents (Solvent Scrubbing Process)

Alkanolamines mainly Monoethanol amine (MEA), combinations of alcohols and ammonia, is commonly used as a solvent. Demerits: High investment costs and energy consumption. Tedious material handling procedures. High maintenance cost due to MEA’s corrosion effect

B. Using Physical Absorption Principle: Absorbents allow a gas to permeate a solid or liquid under one set of conditions, and desorb under others. The rate of absorption or desorption is temperature and pressure dependent. Physical Solvents Selexol, a liquid glycol-based solvent, to process natural gas, both for bulk CO2 removal and H2S removal Glycol effective for capturing both CO2 and H2S at higher concentration. Glycerol carbonate high selectivity for CO2 , relatively low capacity

C. Gas separation membranes Factors: Permeability: rate of flow through the membrane due to pressure difference. Selectivity: The ability of one gas to permeate faster than another. Membranes could be: polymer membranes palladium membranes, Molecular membranes. Solubility-selective polymer membrane removing CO2 from CO2/CH4 mixture. Red: methane Grey: carbon dioxide

Capturing Carbon Dioxide Methods on basis of fuel combustion : Pre-Combustion Post-Combustion Oxy-fuel Combustion

Pre Combustion Capture Involves converting fossil fuel into hydrogen and carbon dioxide by gasification. During pre-combustion, Step 1. Coal transformed into syngas .(mixture of carbon monoxide and hydrogen) Step 2. Carbon monoxide is shifted further with water to carbon dioxide and an extra amount of hydrogen. Step 3. Carbon dioxide is separated from the hydrogen through Glycol-based solvent Selexol. or Membrane separation units Step 4. The hydrogen is subsequently combusted in the gas turbine of the power plant.

Schematic diagram showing Pre-combustion capture of CO2 Source: http://www.powerplantccs.com/ccs/cap/con/pos/pos.html

Post Combustion Capture Focuses directly on power plant emissions, such as flue gases. Carbon dioxide removed from post-combustion flue gas using regenerable solvents. The solvent most frequently encountered is MEA, an amine solvent. Source: http://www.powerplantccs.com/ccs/cap/con/pos/pos.html

Oxy Fuel Combustion Method Principle: Combustion in pure oxygen produces water and pure CO2 exhaust. CO2 can be captured at relatively low-cost through cooling and compression Demerits: The main problem with this method is separating oxygen from the air. Usually completed cryogenically which requires a lot of energy and hence is very expensive.

CO2 Transportation Stage that links sources and storage sites. CO2 transported via any of three states : 1. GAS Occupies large volume, hence large facilities are needed. Compressed for transportation by pipeline. 2. LIQUID Can be carried by rail ,road tankers and dedicated pipelines. Transport costs reduced when CO2 pressurized to liquid form 3.SOLID Solidification needs much more energy compared with other options Inferior from a cost and energy viewpoint.

Saline-filled basalt formations (with highly impermeable cap rock) Captured Carbon Storage or Sequestration Option1: Utilization Option 2: Storage in : Oil and gas fields Saline formations Unmineable coal seams. Saline-filled basalt formations (with highly impermeable cap rock)

Drawbacks of Capturing and Storing Treats carbon dioxide as a waste High start-up cost with no economical advantage. High energy inputs and costs. Difficulty in finding suitable sites. Uncertainty regarding CO2 leakage into groundwater and soil

Possible ways for Carbon Utilization Accelerated mineralisation through carbonisation of rocks Reaction of minerals (mostly calcium or magnesium silicates) with CO2 into inert carbonates. Eg: Slag. These carbonates can then be used for example as construction materials. Biorenewable fuels and materials from algae Microalgae have a high biomass productivity compared to terrestrial crops and can be cultivated on non-arable land.

the cultivation of microalgae in open ponds directly captures and utilise CO2. Per tonne of algae biomass ca. 0.5 tonne carbon can be fixed and converted. Using waste CO2 as a chemical feedstock for the synthesis of other chemicals.

Study of a Carbon Capture and Storage project in Canada

Process: Post-Combustion Capture

Project Description One of the first large-scale efforts in the world to promote carbon capture. Carbon Capture and Isolation done via Post Combustion method in coal-fired electricity power plant. . Transportation Through intense pipeline network across the Canada–US border Utilization and Storage injected at the Weyburn-Midale oil fields for enhanced oil recovery. acts as a pressurizing agent Reduces viscosity of oil. later be injected for permanent sequestration in a saline aquifier.

Weyburn field and Apache’s Midale field, located in southeast Saskatchewan, Canada,

Expected Outcomes Estimated budget : $1.24 billion. Capturing up to 1 Mt per year of CO2 by 2015. Storage to hold roughly 40 million tonnes of CO2 that otherwise been vented into the atmosphere. A coal-fired power generating unit of capacity 100 MW of net clean power. A demonstration project for the development of sound regulation and policies.

Conclusion CCU has a potential to regulate Carbon dioxide emission. BUT, It still has a long way to go as: Still in the research and development phase. Has not yet been commercialized. Huge initial investment is required.

REFERENCES: Anderson S, Newell R. Prospects for Carbon Capture and Storage Technologies. January 2003. Discussion Paper 02–68. pp 23-32 & pp 47-51. Hermann W. An Assessment of Carbon Capture Technology and Research Opportunities. Spring, 2005. GCEP Energy Assessment Analysis Styring P, Jansen D. Carbon Capture and Utilisation in the green economy. July 2011.. Report no. 501. Publisher: The Centre for Low Carbon Futures 2011. pp 6-13. www.nrcan.gc.ca/eneene/pubpub/pdf/ccscsc-eng.pdf Date of Visit: 9/9/11. http://www.saskpower.com/sustainable_growth/projects/carbon_capture_storage.html Date of Visit: 9/9/11. http://www.powerplantccs.com/ccs/cap/con/pos/pos.html Date of Visit: 9/9/11. http://www.powerplantccs.com/ccs/cap/con/pre/pre.html Date of Visit: 6/9/11 http://www.ptrc.ca/weyburn_overview.php Date of Visit: 6/9/11.