烃类催化裂解和氧化耦合反应制低碳烯烃

烃类催化裂解反应是强吸热过程,而金属氧化物和烃类的氧化反应是放热反应。在反应器中使两类反应同时进行,通过热量的耦合,提供部分催化裂解反应所需的热量。采用脉冲反应和固定床绝热反应装置对这种耦合反应进行了研究。脉冲反应结果表明,金属氧化物和烃类发生氧化反应(放热反应)存在热量耦合的作用。固定床绝热反应结果表明,与纯催化裂解催化剂(低碳烯烃(乙烯+丙烯)的收率为25.79%)相比,含有金属氧化物(CuO和M n2O3)的耦合催化剂在反应过程中金属氧化物被还原,同时生成H2O和COx,催化剂的床层温度随反应的进行温降幅度减小,低碳烯烃(乙烯+丙烯)的收率增加幅度不大(26.16%),说明该反应存在热量耦合的作用。

Preparation of Lower Olefins by Coupling of Catalytic Cracking and Oxidation of Hydrocarbons

The catalytic cracking of hydrocarbons to olefins is an endothermic reaction,and their oxidation is exothermic.Addition of metal oxides to catalytic cracking system would provide heat energy for hydrocarbons cracking,for the lattice oxygen of the metal oxides would react with the hydrocarbons and emit heat.The pulse reaction and adiabatic reaction in fixed bed were carried out to investigate the coupling of catalytic cracking and oxidation.In pulse reaction,hexane was used as reactant and the mixture of HZSM-5 molecular sieve with LaMnO_3 was used as coupling catalyst.The results ensured that heat coupling existed in hydrocarbon oxidation with the metal oxides.In fixed bed operation,HZSM-5 molecular sieve was used as cracking catalyst,and CuO and Mn_2O_3 as oxidation catalyst.H_2O and CO_x were formed during adiabatic fixed bed process,and metal oxides were deoxidized.Temperature falling amplitude of catalyst bed during coupling reaction was less than that of sole cracking,and yield of olefins(C_2H_4+C_3H_6)could reach 26.16%,which was close to yield of sole cracking(25.79%).This result convincedly indicated that the partial heat of cracking was provided by oxidation.