CaO对焦炭在CO2+20％H2O气氛下溶损动力学的影响OA

To investigate the solution-loss properties of high-reactivity cokes in a hydrogen-rich blast furnace,the solution-loss processes of basic coke(BC)and high-reactivity coke with CaO(BC+Ca)at 1 000,1 100,1 200 ℃under CO2+20％H2O(volume fraction,the same below),N2+20％H2O,and CO2 atmosphere were studied.The kinetics of Boudouard reaction(C+CO2=2CO)and water-gas reaction(C+H2O=CO+H2)were analyzed by detecting the mole percent of CO and H2 in the off-gas,to study the effect of CaO on the solution-loss kinetics of cokes in a CO2+20％H2O atmosphere.The results show that the Boudouard reaction rates of BC and BC+Ca cokes in CO2+20％H2 O atmosphere are lower than those in CO2 atmosphere,and the water-gas reaction rates of BC and BC+Ca cokes are also lower than those in N2+20％H2O atmosphere,which indicates that there is a competition between the reactions of H2O and CO2 with cokes.The Boudouard reaction rate and the water-gas reaction rate of BC+Ca coke are larger than those of BC coke,which shows that CaO has a catalytic effect on both reactions.CaO addition can decline Ea for the Boudouard reaction about 22.1～24.5 kJ/mol and Ea for the water-gas reaction about 37.8～38.9 kJ/mol.Furthermore,the ratio C(kH/kC)of the water-gas reaction rate constant to the Boudouard reaction rate constant is proposed to characterize the competitiveness of H2O to CO2.The results show that the catalytic effect of CaO on the water-gas reaction is stronger than that of the Boudouard reaction,which increases from 6.1％to 20.0％compared with the C value of coke at 1 000～1 200 ℃.The silica-aluminate existing states of Ca in cokes are calcium aluminosilicates,which effectively improve the competitiveness of H2O to CO2.