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Why ocean sequestration?

Effects of Vertical DIC Distribution on Storage Efficiencies of Direct Injection of CO2 into the Ocean. Baixin Chen, M. Nishio, and M. Akai National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba East, Tsukuba 305-8564, Japan. Why ocean sequestration?.

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Why ocean sequestration?

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  1. Effects of Vertical DIC Distribution on Storage Efficiencies of Direct Injection of CO2 into the Ocean Baixin Chen, M. Nishio, and M. AkaiNational Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba East, Tsukuba 305-8564, Japan

  2. Why ocean sequestration? • Large capacity (IPCC Srpt. on CCS 05) : • “Roughly 2,300 to 10,700 GtCO2 would be added to the ocean (above the natural pre-industrial background) in equilibrium with atmospheric CO2 stabilization concentrations ranging from 350 ppm to 1000 ppm, regardless of whether the CO2 is initially released to the ocean or the atmosphere.” • Actually, it is an artificially acceleration of natural oceanic uptaking of CO2 across air/sea interface. • Over the past 200 years the oceans have taken up 500 GtCO2 from the atmosphere out of 1300 GtCO2 total anthropogenic emissions. .

  3. Questions: • Assessments on CO2 Ocean Sequestrations • How long the CO2 injected could be kept in the ocean ? (efficiency) • Is it safe for marine organisms and animals? (bio-impacts in near and far fields) • The long-term impacts on global ecosystem ( ? )

  4. How to perform (IPCC Srpt. on CCS, 2005)

  5. Injection of CO2 by moving-ships

  6. CO2 Injection Nozzle & Droplet Size Distribution(Minamiura et al., GHGT-7, 2004) • Drop deformation • Hydrate layer formed at the interface Nozzle and CO2 drops from Lab. Exp.

  7. How long the CO2 injected could be kept in the ocean ? • Efficiency orretention: • OGCMs (depth, locations) • Caldeira et al. (GRL, JGR , 02) • Orr et al. (Climate Change 02 and GHGT-5-00 ) • ….. • Box models (depth, bio-chemical systems) • Herzog et al. (Climatic Change, 2003) • Sohma et al, (JGR, 20050) • …. In this study : • If the injection parameters play the role on storage efficacy?

  8. How to handle the injection parameters ? • 1. Plume dynamics (coupling the injection parameters and currents) in short-term • 2. For long-term efficiency, • By OGCMs for long-term • Using fine resolution: • 10th meters vertically (Very difficult if not impossible currently) • Nesting grids systems • Good and will be trying By Box models • OK (How about the horizontal transportation roles?) In this study : Implemented the initial vertical distribution of DIC from (1) to the existed data from (2).

  9. Effect of injection parameters on storage efficiency: : the storage efficiency with an initial vertical distribution (pdf) : the storage efficiency without initial vertical distributions (OGCM data). h : the depth of the ocean (m) t : time (year) P[x(h)] : the mass pdf of DIC initial vertical distributionas a normalized depth (x (h)).

  10. Long-term storage efficiency data interpolated from OGCMs

  11. The data can be interpolated numerically(Caldeira et al. GRL 2002) Injection site: Tokyo Injection site: Tokyo T > 100 years T = 120 - 500 yrs T < 100 years T = 20 - 100 yrs

  12. Initial Vertical Distributions of DIC produced by coupling injection parameters with ocean current from two-phase models

  13. Near-field Two-phase Model Ocean surface Towing pipe Initial DIC distribution Turbulent diffusion X3 CO2 droplet Dynamics and biological impacts X2 X1 Injection ports installed nozzles Can go to the bottom

  14. Evolution of DIC Plumes (Chen et al., JGR, 05) T=23 min T=70 min T=1.0 min Injection rate : 100 kg/sec Initial drop size: 15 mm Injection depth : 2000 m Injection port : Horizontal X=10 m X=180 m X=10 m X=10 m

  15. Vertical distributions of DIC Injection site: Tokyo at Depth of 2000 m

  16. Effect of initial DIC vertical distribution on efficiency

  17. CO2 Injection Parameters Injection type: Moving-ship Injection rate: 100kg/sec by moving-ship (0.1 Ggt C /year) Droplet sizes: 5, 10, 15, 20, 30, 40 mm Injection depth: 1000, 1500, 2000, 2500 m Injection site: Near Tokyo (T, S and current data )

  18. Effects of initial droplet size on efficiency Injection site: Tokyo

  19. Effects of injection parameters on efficiencies Injection site: Tokyo Time : 500 yrs

  20. Efficiency and (Sensitivity) * : H = 1000 m and D0 = 5 – 10 mm; ** : H = 2500 m

  21. Conclusions & discussions Within 500 years after releasing CO2 at rate of 0.1 Ggt C /year by moving-ship: • Efficiency is related with not only depths and sits but also drop size injected. • For droplets size D0 = 5 – 40 mm, the storage efficiencies could be reduced by range of 5% to 20% if release depth less than 2600m due to the rising plumes. • Implement of DIC vertical pdf into OGCM for further checking. (Nesting grids system ?) • The roles of injection parameters on biological impacts in near-field should is another challenge.

  22. Thank you !

  23. In this study: • Assessments on CO2 Ocean Sequestrations • How long it could be kept in the ocean ? (efficiency) • OGCMs (depth, locations) (Caldeira et al. in GRL, JGR 02; Orr et al. in Climate Change 02 and GHGT-5-00; …..) • Box models (depth, bio-chemical systems) (Sohma et al, JGR-05, ….) • How about the injection parameters? • Is it safe for marine bio-masses? (bio-impacts) • Lab. Exps. (Acute injury of fishes, Mortality and Injury of zooplankton by Portner; Shirayama; Ishimatsu; JO and IPCC SRPT. on CCS) for Near-field and short-terms. • Long-term impacts on bio-eco system ( ? ) Do the Injection parameters play the role ? • The impacts on global ecosystem ( ? )

  24. Methodologies: • Implement the near-filed two-phase box model to the OGCM by: • Provide the initial vertical distributions of DIC from near-filed model • Use data of long-term storage efficiency from OGCMs and Box models to estimate the effects of initial-vertical DIC distribution. because the time scales : dtOGCM (2 ~ 3 hrs) > Tdiss (1~ 1.5 hrs) • We checked the injection depths and D0s for two injection types (horizontal and vertical injection ports) at a fixed injection rate (100kg/sec).

  25. Model validation (vs field Exp data by P. Brewer et al. 2002)

  26. Ascending /Descending of CO2 droplet in the ocean

  27. Model of an Individual CO2 Droplet (dissolution and movement) • Key Parameters: • Sh : Sherwood number • Cs: The solubility • α : The effective area coefficient • Cd: Drag coefficient

  28. Sub-models of drag coefficient(Lab. data from Dr. Ozaki) ur =|ud – uw| The relative velocity

  29. Near-filed Bio-impacts for two CO2 release types Elapsed time: 180 min Horizontal release type Vertical release type

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