CO₂ gasification reactivity and the apparent reaction order of chars derived from calcium-rich and calcium-poor lignites have been investigated via thermogravimetry analysis (TGA) in the temperature range from 825 to 900 °C and the CO₂ partial pressure range from 0.015 to 0.1 MPa. Chemical forms of Ca species in raw and partially-gasified chars are characterized via X-ray diffraction (XRD). Results indicate that CaO carbonation during the char-CO₂ gasification is a direct cause of Ca deactivation, which shows temperature and pressure dependence and follows the equilibrium regularity of CO₂ over CaCO₃ at different temperatures. The Ca in lignite chars plays a catalytic role at the CO₂ partial pressures below 0.1 MPa at temperatures of 875 and 900 °C, while Ca deactivation occurred when the CO₂ partial pressures are above 0.05 MPa at 825 °C and above 0.075 MPa at 850 °C. On the one hand, this fact suggests that Ca deactivation exhibits temperature and pressure dependence. On the other hand, char gasification may follow different catalytic mechanisms in the CO₂ partial pressure range from 0.015 to 0.1 MPa, from which the determination of the apparent reaction order is less reasonable. The coefficient of determination (R²) reflects the goodness of r-P_CO2 fitting, which becomes poor with the increase of CO₂ partial pressure when CaO carbonation takes place. Choosing an appropriate CO₂ pressure range for a given temperature is necessary to eliminate the effects of Ca deactivation on the determination of gasification reactivity and the apparent reaction order. The apparent reaction order of chars determined at conditions without Ca deactivation increases as the gasification temperature decreases.

CO ₂气化反应性和字符的表观反应顺序从钙丰富和钙差褐煤衍生通过热重分析（TGA）的温度范围内从825至900℃和CO已经研究₂至分压范围从0.015 0.1兆帕 通过X射线衍射（XRD）表征原始和部分气化的焦炭中钙物质的化学形式。结果表明，char-CO ₂气化过程中CaO碳化是Ca失活的直接原因，Ca失活表现出温度和压力依赖性，并且在不同温度下遵循CO _2相对于CaCO ₃的平衡规律。褐煤焦中的Ca对CO ₂起到催化作用分压在875和900°C时低于0.1 MPa，而当CO ₂分压在825°C高于0.05 MPa和在850°C高于0.075 MPa时发生Ca失活。一方面，这一事实表明Ca的失活表现出温度和压力的依赖性。另一方面，焦炭气化可在0.015至0.1MPa的CO ₂分压范围内遵循不同的催化机理，由此表观反应顺序的确定较不合理。测定系数（R ²）反映了r - P _CO2拟合的优劣，随着CO ₂的增加而变差。CaO碳化时的分压。必须选择给定温度的合适CO ₂压力范围，以消除Ca失活对气化反应性和表观反应顺序的影响。在没有Ca失活的条件下确定的炭的表观反应顺序随气化温度降低而增加。