Ocean Sequestration of Carbon Dioxide:  Modeling the Deep Ocean Release of a Dense Emulsion of Liquid CO₂-in-Water Stabilized by Pulverized Limestone Particles

Abstract

The release into the deep ocean of an emulsion of liquid carbon dioxide-in-seawater stabilized by fine particles of pulverized limestone (CaCO3) is modeled. The emulsion is denser than seawater, hence, it will sink deeper from the injection point, increasing the sequestration period. Also, the presence of CaCO3 will partially buffer the carbonic acid that results when the emulsion eventually disintegrates. The distance that the plume sinks depends on the density stratification of the ocean, the amount of the released emulsion, and the entrainment factor. When released into the open ocean, a plume containing the CO2 output of a 1000 MW(el) coal-fired power plant will typically sink hundreds of meters below the injection point. When released from a pipe into a valley on the continental shelf, the plume will sink about twice as far because of the limited entrainment of ambient seawater when the plume flows along the valley. A practical system is described involving a static mixer for the in situ creation of the CO2/seawater/pulverized limestone emulsion. The creation of the emulsion requires significant amounts of pulverized limestone, on the order of 0.5 tons per ton of liquid CO2. That increases the cost of ocean sequestration by about $13/ ton of CO2 sequestered. However, the additional cost may be compensated by the savings in transportation costs to greater depth, and because the release of an emulsion will not acidify the seawater around the release point.

Nanoparticle-stabilized carbon dioxide-in-water foams with fine texture

“…However, this approach has received relatively little attention for nanoparticles at the CO 2 -water interface. Golomb and coworkers report both C/W [33][34][35] and W/ C [34] emulsions depending on material used, where hydrophilic materials created C/W and hydrophobic materials created W/C. The hydrophilic materials used included sand, limestone, and flyash, indicating that interfacially active nanoparticles can manufactured from extremely low cost materials.…”

Superparamagnetic nanoclusters coated with oleic acid bilayers for stabilization of emulsions of water and oil at low concentration

“…Nanoparticles are of recent interest for subsurface applications including mobility control in oil recovery [18], and CO 2 -enhanced oil recovery and/or CO 2 sequestration [14,19]. Furthermore, we propose that aqueous magnetic nanoparticle dispersions may be used as imaging agents for the detection and visualization of interfaces of water and oil in subsurface reservoirs.…”

Ocean sequestration of carbon dioxide (CO2)

“…This would require about 2.3 tonnes of pulverized limestone per tonne of Co 2 , raising the cost of deep ocean storage of Co 2 substantially in terms of raw materials, handling and transport. Golomb et al (2007) proposed the release of a CO 2 /water emulsion stabilized by very fine limestone (CaCO 3 ) particles. As described below, this method of release will require far less than stoichiometric quantities of CaCo 3 , and may greatly alleviate the seawater acidification problem.…”

“…liquid Co 2 is barged to the platform and stored in a tank. Pulverized limestone is barged to the platform and slurried with seawater pumped from a depth of 11.5 Emulsion consisting of 33.3 % by volume liquid CO 2 , 66.7 % by volume artificial seawater (3.5 % NaCl solution) and 0.5 kg pulverized limestone per kg of liquid CO 2 (adapted from Golomb et al, 2007).…”