超临界状态下吸热碳氢燃料正十二烷的催化裂解研究

Study on the Catalytic Cracking of Endothermic Hydrocarbon Fuel n-Dodecane Under Supercritical Condition

在超临界状态下，采用HZSM-5型分子筛催化剂对正十二烷的催化裂解反应进行了研究，考察了裂解温度、压力与正十二烷转化率、气液相产物的关系，以及积炭量与反应压力、温度的关系。实验结果表明，超临界状态下，在400℃-500℃之间进行反应时，转化率随温度升高而增加，气体产率随裂解温度的升高而增加，以400℃～450℃之间尤为明显。转化率、气体产率随压力的升高而降低。450℃是较适合的反应温度。在超临界条件下，反应物流正十二烷成为超临界流体，可以将反应过程中生成结焦或积炭等难溶物的前驱体溶解，随反应物流流出催化荆孔道，减少催化剂上的积炭量。

Under supercritical condition and using HZSM-5 as catalyst, catalytic cracking of n-dodecane was performed to investigate the effects of reaction conditions. The results indicate that the conversion of n-dodecane to products increases with the rising of reaction temperature. The higher reaction temperature leads to the higher yield of cracking gases, especially from 450℃ to 500℃, while the conversion of n-dodecane and gases yield decrease under higher reaction pressure. The 450℃ is the reasonable reaction temperature.Coke precursors can be dissolved in the supercritical fluid and flow out of the catalyst pore, so the coke deposit on the catalyst decreases under supercritical condition.