Chong Kul Ryu

Performance analysis of K-based KEP-CO2P1 solid sorbents in a bench-scale continuous dry-sorbent CO2 capture process

Korea Institute of Energy Research (KIER) and Korea Electric Power Corporation Research Institute (KEPCORI) have been developing a CO2 capture technology using dry sorbents. In this study, KEP-CO2P1, a potassium-based dry sorbent manufactured by a spray-drying method, was used. We employed a bench-scale dry-sorbent CO2 capture fluidized-bed process capable of capturing 0.5 ton CO2/day at most. We investigated the sorbent performance in continuous operation mode with solid circulation between a fast fluidized-bed-type carbonator and a bubbling fluidized-bed-type regenerator. We used a slip stream of a real flue gas from 2MWe coal-fired circulating fluidized-bed (CFB) power facilities installed at KIER. Throughout more than 50 hours of continuous operation, the temperature of the carbonator was maintained around 70-80 °C using a jacket-type heat exchanger, while that of the regenerator was kept above 180 °C using an electric furnace. The differential pressure of both the carbonator and regenerator was maintained at a stable level. The maximum CO2 removal was greater than 90%, and the average CO2 removal was about 83% during 50 hours of continuous operation.

A long-term test of a new CO2 sorbent (KEP-CO2P2) in a 0.5 MWe CO2 capture test bed

The performance of a new dry CO2 sorbent KEP-CO2P2 was tested for an extended period of time of 650 hours in a 0.5 MWe CO2 capture test bed at Hadong coal-fired power plant. The mass-produced CO2 dry sorbent, KEP-CO2P2 was tested for CO2 sorption and regeneration capacity. With modification of the process as well as the use of KEP-CO2P2 sorbent in a 0.5 MWe CO2 capture test bed, 85% (81–90%) CO2 removal rate was achieved in continuous operation of 650 hours. Samples were collected and analyzed using particle size analyzer (PSA), ion chromatograph (IC), inductively coupled plasma (ICP), field emission-scanning electron Microscope (FE-SEM), electron probe X-ray micro-analyzer (EPMA) and X-ray diffractometer (XRD). The analysis showed that KEP-CO2P2 was not affected by SOx, and there were no side reactions to consume K2CO3. However, the regeneration of the sorbent was not complete to need future investigation.

Distribution of NiO/Al2O3/NiAl2O4 in the Fabrication of Spray-Dry Oxygen Carrier Particles for Chemical-Looping Combustion

NiO/Al2O3, known as one of the most efficient oxygen carrier, has been fabricated by spray-drying method and calcinated at 1100 °C and 1300°C, and the structural characteristics are investigated using XRD, SEM, TEM and XPS. For the characterization of surface and bulk microstructure of the fabricated NiO/Al2O3 oxygen carrier particle, investigated were 1) as-fabricated powders, 2) internal structure of the crumbled particles, and 3) cross-sectional specimens. The results showed that the fabricated oxygen carrier formed well distributed NiAl2O4 with NiO particles of 100~500 nm via reaction keeping on the mole ratio. The oxygen carriers developed in this study showed pertinent characteristics for chemical-looping combustion, and good effect on the strength, indicating a potential for wide application in the future. The calcination at 1100 °C was good enough and as efficient as that at 1300 °C.

Cleaning of gaseous hydrogen chloride in a syngas by spray-dried potassium-based solid sorbents

There are corrosive gases such as H2S and HCl in a coal- or biomass-derived syngas. HCl can be removed by Na2CO3 or K2CO3 at hot temperatures. Hot syngas cleaning has the advantage of improving thermal efficiency. We investigated HCl removal by spray-dried potassium-based solid sorbents which were originally developed for post-combustion CO2 capture. Both fresh and spent CO2 sorbents were tested to confirm the applicability as a sorbent for HCl cleaning. Saturation chlorine sorption capacity was measured using a fixed-bed reactor at a temperatures of 300–500 °C under an ambient pressure. Both fresh and spent CO2 sorbents showed saturation chlorine sorption capacity above 15 wt%. HCl removal performance of the sorbents was investigated in a micro fluidized-bed reactor and a bench-scale bubbling fluidized-bed reactor. HCl concentration was lowered from 150–900 ppmv to less than 5 ppmv and from 130–390 ppmv to less than 1 ppmv in a micro fluidized-bed reactor and in a bench-scale bubbling fluidized-bed reactor, respectively, at 300–540 °C and 20 bar. It could be concluded that both fresh and spent spray-dried potassium-based CO2 sorbents could be utilized as a disposable HCl sorbent for hot syngas cleaning.