A Diamine-Based Integrated Absorption-Mineralization Process for Carbon Capture and Sequestration: Energy Savings, Fast Kinetics, and High Stability.

ABSTRACT

The high energy requirement of amine regeneration and the uncertainty of safe disposal of the captured CO2 remain big challenges to the large-scale implementation of amine scrubbing process for CO2 capture. Mineral carbonation represents a safe and permanent route to capture and store CO2 with net energy production but typically proceeds at a slow reaction rate. Here, we present a new integrated absorption and mineralization (IAM) process that couples a diamine-based CO2 absorption with fly-ash-triggered amine regeneration. The technical feasibility of the IAM process using 3-diethylaminopropylamine (DEAPA) and CaO-containing materials such as CaO and coal fly ashes was verified, and the reaction mechanism involved was investigated. It was found that CaO and CaO-rich coal fly ash were effective to regenerate DEAPA via the decomposition of DEAPA carbamate species and the formation of calcium carbonate precipitates. Furthermore, the diamine-based IAM process displayed a fast kinetics and a high stability for CO2 sequestration and can reduce the leachability of some heavy metals in the fly ash. These process properties render this diamine-based IAM process a great potential for carbon capture and sequestration applications.