Investigation of CO2 hydrate slurry flow characteristics with particle dissociation for carbon storage and transportation

CO2 capture and storage technology is an effective method to mitigate the greenhouse effect and hydrate slurry is a high-efficiency way of CO2 transportation. In this study, in order to further reduce the cost and improve the transportability, a new CO2 hydrate slurry transport mode which allows a small part of hydrate particles to dissociate during flow process is proposed. To investigate the CO2 hydrate slurry flow characteristics and particle micro behaviors, a multiphase flow model coupled with hydrate dissociation kinetic model and population balance model is established. Experimental results are used to verify this integrated model. Furthermore, the effects of hydrate dissociation on CO2 transportability are also analyzed. The results indicate that the dissociation rate of hydrate during flow process can be divided into rapid dissociation stage and weakened dissociation rate stage. The agglomeration of hydrate particle can reduce the total surface area, further resisting the dissociation rate. The hydrate particle size experiences a process of growing to dynamic balance. The hydrate dissociation can decrease the mean viscosity of CO2 hydrate slurry flow, which can reduce the pressure drop and energy loss compared with the flow without hydrate dissociation. The generated bubbles can accelerate the CO2 hydrate slurry flow, increasing the transportability and reducing the risk of hydrate blockage in pipe induced by agglomeration.