CO2 capture from flue gas using potassium-based dry regenerable sorbents

Abstract

Dry regenerable sorbent technology is one of the emerging technologies as a cost-effective and energy-efficient technology for CO2 capture from flue gas. Six potassium-based dry regenerable sorbents were prepared by spray-drying techniques. Their physical properties and reactivities were tested to evaluate their applicability to a fluidized-bed or fast transport-bed CO2 capture process. Each sorbents contained 35 wt% of K2CO3. All sorbents were sufficient with either attrition resistance or reactivity, or both properties. Sorb KT-5 and KZ-5 sorbents satisfied most of the physical requirements for a commercial fluidized-bed reactor process along with good chemical reactivity. These sorbents had a spherical shape, an average size was 134, 121 μm, respectively. The particle size distribution of these two sorbents had the same range of 40–250 μm, and the bulk density of approximately 0.85 g/mL. The attrition index (AI) of Sorb KT-5 and Sorb KZ-5 reached below 3% compared to about 20% for commercial fluidized catalytic cracking (FCC) catalysts. CO2 sorption capacity of Sorb KT-5 and Sorb KZ-5 was range of 6–10 wt% in the simulated flue gas condition. These sorbents showed almost-complete regeneration at temperatures less than 140 °C.