Direct injection of CO_2 hydrate composite particles for ocean carbon storage: field experiments and plume modeling

摘要

Negatively buoyant composite particles, consisting of solid CO_2 hydrate plus unreacted liquid CO_2 and seawater, provide an attractive vehicle for direct ocean storage of CO_2. Previous field experiments have documented the settling properties of small-diameter (up to～0.7 cm) cylindrical composite particles produced from a continuous jet hydrate reactor. Here we summarize results of recent (April 2006) field experiments off Monterey CA with larger diameter (2.5 cm) particles, and describe mathematical model predictions with continuously injected particles with diameters of 0.7, 2.5 and 5.0 cm. Model results show that sinking of both individual particles and particle plumes increases with mass loading and particle diameter, but the "plume effect", or ratio of plume settling to individual particle settling, is greatest for large mass flowrate and small particle size.