Details

Autor(en) / Beteiligte

• Zhang, Wan
• Li, Yingjie
• Qian, Yuqi
• Li, Boyu
• Zhao, Jianli
• Wang, Zeyan

Titel

NO removal performance of CO in carbonation stage of calcium looping for CO2 capture

Ist Teil von

• Chinese journal of chemical engineering, 2021-09, Vol.37 (9), p.30-38

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2021

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• [Display omitted] Calcium looping realizes CO2 capture via the cyclic calcination/carbonation of CaO. The combustion of fuel supplies energy for the calciner. It is unavoidable that some unburned char in the calciner flows into the carbonator, generating CO due to the hypoxic atmosphere in the carbonator. CO can reduce NO in the flue gases from coal-fired power plants. In this work, NO removal performance of CO in the carbonation stage of calcium looping for CO2 capture was investigated in a bubbling fluidized bed reactor. The effects of carbonation temperature, CO concentration, CO2 capture, type of CaO, number of CO2 capture cycles and presence of char on NO removal by CO in carbonation stage of calcium looping were discussed. CaO possesses an efficient catalytic effect on NO removal by CO. High temperature and high CO concentration lead to high NO removal efficiency of CO in the presence of CaO. Taking account of better NO removal and CO2 capture, the optimal carbonation temperature is 650 °C. The carbonation of CaO reduces the catalytic activity of CaO for NO removal by CO due to the formation of CaCO3. Besides, the catalytic performance of CaO on NO removal by CO gradually decreases with the number of CO2 capture cycles. This is because the sintering of CaO leads to the fusion of CaO grains and blockage of pores in CaO, hindering the diffusion of NO and CO. The high CaO content and porous structure of calcium-based sorbents are beneficial for NO removal by CO. The presence of char promotes NO removal by CO in the carbonator. CO2/NO removal efficiencies can reach above 90%. The efficient simultaneous NO and CO2 removal by CO and CaO in the carbonation step of the calcium looping seems promising.