Abstract

Implementing efficient carbon capture within mine tailings on an industrial scale holds significant promise for providing permanent and impactful solutions to carbon removal from the environment. This research rigorously explores the techno-economic feasibility of carbon sequestration in mine tailings through flue gas injection. The study encompasses a broad spectrum, delving into large-scale implementation, operational feasibility in cold climates, and addressing techno-economic aspects associated with diesel exhaust injection in mine tailings for carbon sequestration.

Upon delineating the research scope, the investigation conceptualizes a design for large-scale CO₂ sequestration within dry stack mine tailings. This involves the use of embedded perforated pipes to inject the flue gas. A pivotal contribution of this study lies in the conception and validation of a novel (1+1)D Reduced Order Model (ROM). This model predicts the pressure dynamics of perforated pipes within the dry stack tailings with a precision comparable to commercial numerical solvers but with significantly reduced computational resources and time. The developed model is a valuable tool in decision-making by providing a strategy for designing energy-optimal injection scenarios.

The research also advances the development and validation of a numerical model that assesses the feasibility of harnessing thermal energy from flue gas to prevent freezing in tailings beds. This breakthrough allows the investigation of the feasibility of the year-round carbon capture operation in cold climates. By quantifying crucial parameters, such as injection rate and temperature, the study highlights the adaptability of carbon sequestration approaches in frigid environments. A comprehensive array of sensitivity analyses scrutinizes the concept's viability across diverse operational and climatic conditions.

Furthermore, the study develops a robust techno-economic cost model, incorporating factors such as piping infrastructure and energy operational expenditures. This model aids decision-making by identifying the critical balance between power costs and piping expenditures necessary for optimal operational expenses. Notably, the research underscores that carbon capture within mine tailings can be managed efficiently under reasonable operating costs, reinforcing the practicality of greenhouse gas reduction.