碳质颗粒添加物对渣油热反应生焦的影响

在高压反应釜中研究了三种不同碳质颗粒添加物对克拉玛依常压渣油420℃氮气气氛下热反应生焦的影响。实验结果表明，反应初期碳质颗粒在一定程度上抑制渣油的热反应生焦。碳质颗粒抑制生焦的能力与其表面对极性组分的润湿吸附能力有直接关系，表面易被极性组分润湿的颗粒吸附沥青质的能力强，其抑制渣油生焦的能力也强。碳质颗粒对沥青质的吸附能力和抑制生焦的能力与其比表面积没有直接关系。生焦量随反应时间的变化表明，碳质颗粒在生焦的初期有抑制生焦的作用，后期有促进作用。对甲苯不溶物（TI）的扫描电子显微镜（SEM）和热重（TG）分析表明，和不含添加物的TI相比，含添加物的TI中，小球状甲苯不溶物的数量少、直径小。沥青质和生焦前驱相在碳质颗粒添加物表面的吸附和铺展作用是抑制渣油生焦的主要原因，该作用可以限制生焦前驱相的融并长大，在反应的初始阶段减少生焦量。

Effect of fine carbonous particle additives on coke formation of residue oil thermal reaction

The thermal reaction of Karamay residue oil with three kinds of fine carbonous particle additives was carried out in a batch reactor under N2 atmosphere to investigate the effect of additives on coke formation. The initial N2 pressure was 2.0MPa, the reaction temperature was 420℃ and the additive content was 1w%. The results show that the fine carbonous particles restrain coke formation during thermal cracking of residue oil. The coke restrainability of additives related to their surface properties directly. The additive easily wetted by polar component absorbs asphaltene from asphaltene toluene solution easily, and it also has the stronger ability of restraining coke formation. The abilities of being wetted by polar component, asphaltene absorption and restraining coke among three carbonous additives have the same order: carbon black 1 > active carbon powder > carbon black 2. However, the three abilities have no direct relationship with their specific surface areas. Reactions at different time show that the additives could only restrain the coke formation at the initial period. Once the coke yield is grate enough, the additives does not work. The scanning electronic microscopy (SEM) and thermogravimetric (TG) analysis show that the TI with carbonous additive has less and smaller toluene insoluble spheres than TI without additive. It is concluded that the wetting and spreading of asphaltene and coke precursor phase on carbonous additives are the main reason of restraining coke formation. They constrict the coalescence and growth of coke precursor and coke, and thus reduce the coke yield at a certain reaction time.