Simultaneous NO/SO2 removal by coconut shell char/CaO from calcium looping in a fluidized bed reactor

Abstract

A simultaneous NOx/SO2 removal system using bio-char and CaO combined with calcium looping process for CO2 capture was proposed. The simultaneous NO/SO2 removal performance of coconut shell char/CaO experienced CO2 capture cycles was investigated in a fluidized bed reactor. The effects of reaction temperature, mass ratio of CaO to coconut shell coke, CaO particle size and number of CO2 capture cycles from calcium looping process were discussed. The NO removal efficiency of char is improved under the catalysis of CaO. The reaction temperature plays an important role in the simultaneous NO/SO2 removal. Coconut shell char/CaO achieve the highest NO and SO2 removal efficiencies at 825 oC, which are 98% and 100%, respectively. The mass ratio of CaO to coconut shell char of 60: 100 is a good choice for the simultaneous NO/SO2 removal. Smaller CaO particle size contributes to higher NO and SO2 removal efficiencies of coconut shell char/CaO. The NO and SO2 removal efficiencies of coconut shell char and cycled CaO from calcium looping declined slightly with the number of CO2 capture cycles. In addition, the Ca-based materials balance in process of simultaneous NOx/SO2 removal combined with calcium looping is given. The novel simultaneous NO/SO2 removal method using bio-char and cycled CaO from calcium looping process appears promising.