Process Simulation of Diesel into Aromatics and Carbon Nanotubes: A Techno and Economic Analyses

With the sustainable increase of renewable energy and the maturation of heavy vehicle market, diesel consumption would face a downward trend worldwide. Herein, we have proposed a new route for hydrocracking of light cycle oil (LCO) into aromatics and gasoline and the tandem conversion of C₁-C₅ hydrocarbons (byproducts) into carbon nanotubes (CNTs) and H₂, and by combining the simulation with Aspen Plus software and the experimental study of C₂-C₅ conversion, we have built a transformation network including LCO to aromatics/gasoline, C₂-C₅ to CNTs and H₂, the conversion of CH₄ into CNTs and H₂, and the cycle use of H₂ with pressure swing adsorption. Mass balance, energy consumption, and economic analysis were discussed as a function of varying CNT yield and CH₄ conversion. 50% of H₂ required for hydrocracking of LCO can be supplied by the downstream chemical vapor deposition processes. This can greatly reduce the cost of high-priced hydrogen feedstock. If the sale price of CNTs exceeds 2170 CNY per ton, the entire process would break even for a process of dealing with 520,000 t/a LCO. These results imply the great potential of this route, considering the vast demand and the current high price of CNTs.