Oxy-combustion characteristics as a function of oxygen concentration and biomass co-firing ratio in a 0.1 MWth circulating fluidized bed combustion test-rig

• Published in: Energy (Oxford) 2020-04, Vol.196, p.117020, Article 117020
• Main Authors: Nguyen, Hoang Khoi, Moon, Ji-Hong, Jo, Sung-Ho, Park, Sung Jin, Seo, Myung Won, Ra, Ho Won, Yoon, Sang-Jun, Yoon, Sung-Min, Song, Byungho, Lee, Uendo, Yang, Chang Won, Mun, Tae-Young, Lee, Jae-Goo
• Format: Article
• Language: English
• Subjects: Air pollution; Ash; Biomass; Biomass burning; Biomass co-firing; Bituminous coal; Carbon dioxide; Carbon dioxide emissions; Carbon sequestration; CO2; Combustion; Combustion efficiency; Emission analysis; Energy storage; Firing; Flue gas; Fluidized bed combustion; Fluidized beds; Hardwoods; Lignite; O2 concentration; Oxy-CFBC; Oxygen; Pollutant emissions; Pollutants; Pollution control; Residential energy; Slagging; Sulfur dioxide
• ISSN: 0360-5442; 1873-6785
• DOI: 10.1016/j.energy.2020.117020

Oxy-combustion with a circulating fluidized bed (Oxy-CFBC) can facilitate the separation of high CO2 concentration and reduce emissions by biomass co-firing. This study investigated Oxy-CFBC characteristics such as temperature, solid hold-up, flue gas concentrations including CO2, pollutant emissions (SO2, NO, and CO), combustion efficiency and ash properties (slagging, fouling index) with increasing input oxygen levels (21–29 vol%), and biomass co-firing ratios (50, 70, and 100 wt% with domestic wood pellet). The possibility of bio-energy carbon capture and storage for negative CO2 emission was also evaluated using a 0.1 MWth Oxy-CFBC test-rig. The results show that combustion stably achieved with at least 90 vol% CO2 in the flue gas. Compared to air-firing, oxy-firing (with 24 vol% oxygen) reduced pollutant emissions to 29.4% NO, 31.9% SO2 and 18.5% CO. Increasing the biomass co-firing from 50 to 100 wt% decreased the NO, SO2 and CO content from 19.2 mg/MJ to 16.1 mg/MJ, 92.8 mg/MJ to 25.0 mg/MJ, and 7.5 mg/MJ to 5.5 mg/MJ, respectively. In contrast to blends of sub-bituminous coal and lignite, negative CO2 emission (approximately −647 g/kWth) was predicted for oxy-combustion only biomass. •Oxy-combustion with a 0.1 MWth CFB was operated.•Effect on the various O2 concentrations and biomass firing ratios investigated.•Stable shift from air-to oxy-fired easily achieved above 90% (dry) CO2 flue gas.•Oxy-fired NO and SO2 emissions lower than those of air-fired.•CO2 negative emission from biomass-only oxy-firing expected (−647 g CO2/kWth).