CO_2 Capture from Flue Gas Using Potassium-based Dry Regenerable Sorbents

摘要

Dry regenerable sorbent technology is one of the emerging technologies as a cost-effective and energy-efficient technology for CO_2 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 CO_2 capture process. Each sorbents contained 35 wt% of K_2CO_3. 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. CO_2 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.