Effect of flue gas recirculation on efficiency of an indirect supercritical CO2 oxy-fuel circulating fluidized bed power plant. (15th July 2021)

• Record Type: Journal Article
• Authors: Kim, Hyung Woo; Seo, Su Been; Kang, Seo Yeong; Go, Eun Sol; Oh, Seung Seok; Lee, YongWoon; Yang, Won; Lee, See Hoon
• Is Part Of: Energy. Volume 227(2021)
• Publication Date: 2021-07-15
• Subjects: S–CO2 cycle -- Oxy-fuel combustion -- Circulating fluidized bed -- net efficiency -- Flue gas recirculation; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2021.120487
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: This paper deals with and oxy-fuel circulating fluidized bed (Oxy-CFB) power plant with air separate unit (ASU), CO2 compression and purification unit, and an indirect supercritical CO2 cycle. This novel power plant was designed and modeled by using Aspen Plus at commercial scale to investigate the possibility and the effect of recirculated flue gas conditions. The indirect S–CO2 oxy-CFB power plant had higher net efficiencies compared with oxy-CFB power plant with steam cycles because the phase of CO2 does not change during the operation. Also, the effect of the amount of water retained in flue gas stream generated at the CFB boiler on the overall net efficiency was analyzed. By decreasing the temperature of recirculated flue gas from 90 °C to 40 °C, water retained in flue gas decreased, and input O2 concentration in combustor increased from 34.7 to 38.5 vol%. When flue gas recirculation temperature was 40 °C, the boiler efficiency was 99.6%, and the overall net efficiency was 43.1%. Although approximately 20% of the total power is the power consumption of the ASU and CPU, high net efficiency was achieved in this novel power plant. Graphical abstract: Image 1 Highlights: An indirect supercritical CO2 oxy-CFB power plant was modeled and evaluated. Effects of altering the temperature of fuel gas recirculation were investigated. Energy penalty of ASU and CPU in the oxy-CFB power plant was minimized. The lowering the temperature of FGR can improve the boiler and net efficiency.