ABSTRACT
We reported a new technology for transforming N-containing organic wastes (such as aniline, adiponitrile, and tar from preoxidized PAN fibers) into N-doped carbon nanotubes (N-CNTs) with nanosized iron or nickel catalysts in two consecutive reactors at 650-800 °C. Most of the reactants were converted, and N-CNTs in large amounts were produced in the first stage of the reactor, while the reactants could be completely removed in the second stage of the reactor. The doping content of N-species on CNTs easily approached 10-22 wt %, much higher than most of the earlier reported methods. The results were potentially useful for the treatment of toxic cyano-organics and the production of high-end products simultaneously.
ABSTRACT
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.
