TPR研究载Fe半焦的CO_2气化行为

A STUDY ON CO_2 GASIFICATION OF IRON-LOADED CHARS BY A TEMPERATURE-PROGRAMMED REACTION TECHNIQUE

采用溶液浸渍法，将Ｆｅ￣（３＋）离子担载到扎赉诺尔脱灰煤上，并制成８００℃半焦，使Ｆｅ￣（３＋）变成还原类Ｆｅ￣０。以扎赉诺尔脱灰煤半焦为原料，在热天平上，运用程序升温反应（ＴＰＲ）进行了ＣＯ_２气化研究。从ＤＴＧ曲线上考察Ｆｅ在煤气化过程中的催化行为，以及升温速率对催化反应历程的影响，提出了Ｆｅ在煤气化过程中的催化作用模型。结果表明：Ｆｅ对扎赉诺尔煤半焦的ＣＯ_２气化有着明显的催化作用，随Ｆｅ含量的增高，ＤＴＧ的峰顶温度下降，不受升温速率的影响；并发现，在Ｆｅ的作用下，半焦的气化过程可分为催化和非催化两个反应阶段，而且在高的升温速率下出现多个ＤＴＧ峰，氧化－还原机理可以解释这一现象；Ｆｅ的负载量影响煤焦的孔结构和反应活性。

Zalainor coal chars loaded with ferric nitrate(HTT 800 ℃)were gasified with CO_2 using a temperature-programmed reaction(TPR)technique at several heating rates.Some special features have been noticed in the catalytic gasification. The reactivity of coal chars was estimated. The relationship between the amount of iron-loaded and Twax,Rmax has been established. It was found that the peak temperature of DTG curve decreased with increasing addition of iron in the range of 1～10% by weight. Factors that affect the shape of gasification peaks in the DTG curve were investigated. Special emphasis was given to catalytic effects. Comparison of changes in porosity and reactivity of isothermal simulation with differnt amounts of iron-loaded chars indicates that surface area is a significant, but not the major controlling, parameter for reactivity. The factors influencing the reactivity of char were discussed. An oxygen-transfer mechanism was used to explain the catalytic actions of Fe during gasification in CO_2.