Synthesis of Nanomaterials in a Coaxial Flame

B.Т Lesbayev

doi:10.18321/ectj977

Abstract

The paper presents the results of experimental studies of the synthesis of fullerenes C60 in a coaxial flame of benzene and acetylene at low pressures; of the synthesis of graphene in a coaxial flame of ethanol and propane, benzene, and acetylene; of the soot formation process in the coaxial flame of propane and ethanol. It has been established that the optimum temperature of a coaxial flame for the formation of fullerenes C60 is 970‒1000 °C with the carbon to oxygen ratio in the internal benzene-oxygen flame C/O ≈ 0.9 ÷ 1. The C/O ratio in an external acetylene-oxygen flame was maintained at a stoichiometric ratio. It was found that the preliminary (before feeding into the burner) treatment of the benzene-oxygen mixture using ultraviolet (UV) radiation with a wavelength of 254 nm promotes an increase in the yield of fullerenes. The synthesis conditions were optimized for: 5‒10 layers graphene in a coaxial flame of acetylene and ethanol; graphene containing more than 10 layers in a coaxial flame of propane and ethanol; one and two-layer graphene in a coaxial flame of ethanol and benzene. The possibility of a significant reduction of the formation of soot particles in the diffusion flame of propane by organizing its coaxial combustion with ethanol is shown.

Highlights

Due to the intensive development of the new technologies and the transport industry, the level of energy consumption is increasing, a significant part of which is produced by burning fossil fuels
The toxicity of emitted pollutants depends on the type of hydrocarbon fuel burned and the conditions for organizing the combustion process, as a result of this, the study of problems and issues related to combustion does not lose its relevance
The synthesis of fullerenes C60 in a coaxial flame of benzene and acetylene at low pressures, the synthesis of graphene in a coaxial flame of ethanol with benzene, and the process of soot formation in a coaxial flame of propane and ethanol are studied in this present work

Summary

Introduction

Due to the intensive development of the new technologies and the transport industry, the level of energy consumption is increasing, a significant part of which is produced by burning fossil fuels. The work [10] presents the results of experimental and numerical studies of the influence of the methanol and ethanol addition on the formation of polycyclic aromatic hydrocarbons (PAHs) and soot in the upstream counterflow diffusion flame of ethylene. Based on the results obtained, the authors concluded that in the premixed flame of ethylene, the addition of ethanol has a significant effect on the chemistry of the formation of soot particles and suppresses their growth. The burners are installed in such a way that they allow mixing flames at different heights from the burner surfaces, i.e. at various stages of the development of the reaction This condition makes it possible to regulate the formation of stabilizing combustion products by selecting fuels and changing the concentration density and composition of intermediate particles in the combined reaction zone of the flames. The synthesis of fullerenes C60 in a coaxial flame of benzene and acetylene at low pressures, the synthesis of graphene in a coaxial flame of ethanol with benzene, and the process of soot formation in a coaxial flame of propane and ethanol are studied in this present work

Experimental part

Fullerene synthesis

Graphene synthesis

Soot formation

Conclusion