Effects of SO2/NO on CO2 capture characteristics of K2CO3/Al2O3 in a bubbling fluidized-bed reactor

CO2 capture from flue gas with SO2 or NO using K2CO3/Al2O3 was investigated in a bubbling fluidized-bed reactor. Carbonation and regeneration temperature was 60 degrees C and 350 degrees C respectively. The products after carbonation or regeneration process were detected with XRD and barium sulfate gravimetric method. In addition, the physical properties of the sorbent such as granule morphology, S or N element distribution were measured by SEM-EDX. The five cycle test shows that when the carbonation reaction gas contains SO2, sulfur compounds were generated, which reduces the utilization ratio of K2CO3, the amount of CO2 captured in carbonation process and released in regeneration progress decreased with the circulation times. Element S distributes on the particle surface uniformly and the sulfur content of the product is approximate to the input amount of SO2. When the carbonation reaction gas contains NO, the amount of CO2 captured in carbonation process and released in regeneration progress changed little, XRD and SEM-EDX analysis confirmed that nitrogen compound or element N was not detected in the product. It can be concluded that NO does not react with the sorbent while SO2 has great effect on the sorbent (K2CO3/Al2O3). A 48 times cycle test with different concentration of SO2 and NO in the carbonation reaction gas was conducted, the failure ratio of the sorbent changed when carbonation reaction gases contains different concentration of the acid gas. After the 48 times circulation test, nitrogen compound or element N was not detected in the products.