低温氧化处理对低变质粉煤制备型焦的影响

以低变质粉煤与煤焦油、沥青、焦煤等黏结剂为原料采用成型热解技术制备型焦,主要研究了型煤低温氧化处理对型焦产品组成结构的影响。采用TG-DTG,FT-IR,SEM等对型煤氧化过程及热解产品结构性能进行分析表征。研究表明,空气氧化过程中,型煤中的羰基、羧基等官能团会发生氧化反应生成CO和CO_2,同时脂肪烃和环烷烃的含量有所降低;重质油和沥青与氧气作用发生脱氢聚合反应,生成了芳香程度较高的稠环芳烃大分子物质。氧化处理后型煤中重质组分含量大幅减少,而沥青烯与前沥青烯含量的明显增加是型焦抗压强度提升的主要原因。低变质煤与黏结剂混合样品在空气气氛下的氧化分为两个阶段,室温~120℃主要是原料中水及少量吸附气体的逸出,120℃以后原料中的芳香类物质与氧气发生脱氢聚合反应,生成部分芳香程度较高的稠环芳烃大分子,此阶段的失重率可达到11.08%,最大失重速率峰出现在217.77℃附近。

Effect of low temperature oxidation on preparation of formed coke from low rank pulverized coal

The effect of low temperature oxidation of briquette on the composition and structure of formed coke products was studied,the coke which was prepared from low rank pulverized coal with binders such as coal tar,pitch and coking coal by using molding pyrolysis technology.The oxidation process of briquette and structure and properties of pyrolysis products were characterized by TG-DTG,FT-IR and SEM.The result shows that the carbonyl and carboxyl groups in the briquette are oxidized to produce CO and CO2 during the air oxidation process,meanwhile,the content of cycloalkane and aliphatic hydrocarbons have decreased.In the dehydrogenation polymerization of heavy oil,asphalt and oxygen,the reaction produces polycyclic aromatic hydrocarbon macromolecular substances with higher degree of aromatic.The content of heavy components in briquette after oxidative treatment is greatly reduced,and the apparent increase of content of asphaltene and preasphaltene is the main reason for the increase of compressive strength.The oxidation of mixed samples with low rank coal and binder in air atmosphere is divided into two stages.The first stage is from room temperature to 120 ℃,mainly the escape of water and a small amount of adsorbed gas in the raw material.After 120 ℃,in the dehydrogenation polymerization of the aromatic substances in the raw material and oxygen to produce the part of the aromatic with a higher degree of polycyclic aromatic hydrocarbons.And this stage of weight loss rate can reach 11.08%,the maximum weight loss rate peaks at around 217.77 ℃.