Chemical Kinetics of Methane Pyrolysis in Microwave Plasma at Atmospheric Pressure

Abstract

Results of chemical kinetics modeling in methane subjected to the microwave plasma at atmospheric pressure are presented in this paper. The reaction mechanism is based on the methane oxidation model without reactions involving nitrogen and oxygen. For the numerical calculations 0D and 1D models were created. 0D model uses Calorimetric Bomb Reactor whereas 1D model is constructed either as Plug Flow Reactor or as a chain of Plug Flow Reactor and Calorimetric Bomb Reactor. Both models explain experimental results and show the most important reactions responsible for the methane conversion and production of H 2 , C 2 H 2 , C 2 H 4 and C 2 H 6 detected in the experiment. Main conclusion is that the chemical reactions in our experiment proceed by a thermal process and the products can be defined by considering thermodynamic equilibrium. Temperature characterizing the methane pyrolysis is 1,500-2,000 K, but plasma temperature is in the range of 4,000-5,700 K, which means that methane pyrolysis process is occurring outside the plasma region in the swirl gas flowing around the plasma.

Hydropyrolysis of n-Hexane and Toluene to Acetylene in Rotating-Arc Plasma

“…The materials vary diversely, including gaseous hydrocarbon [2][3][4], liquid hydrocarbon [5,6], coal [7,8], polymer [9,10], biomass [11,12] and solid waste [13,14], etc., and the target products differ from syngas to valuable chemicals such as acetylene, ethylene and carbon nanotube.…”

“…The traditional partial oxidation (POX) process to produce acetylene suffers from lower acetylene selectivity due to the introduction of oxygen [22]. The thermal plasma technology has been applied for the highly endothermic process of acetylene production [3,7,23,24]. Since the process is carried out in the non-oxidative medium with abundant free radicals and high temperature, the C 2 H 2 selectivity is much higher than the POX process, and the conversion of feedstock and yield of gases could be higher than conventional non-plasma pyrolysis.…”

Sewage Sludge-Derived Producer Gas Valorization with the Use of Atmospheric Microwave Plasma

“…Therefore, it may be stated that MWP enables tar compounds conversion due to high temperature and the presence of radicals. However, the radicals may be produced not only due to thermal dissociation but also thanks to vibrational excitation, which is typical for MWP and compounds like CO 2 , H 2 , and N 2 [48,49]. The direct influence of electrons or ions is rather negligible in the case of MWP due to low energy of the former [48] one and low concentration of the latter one [50].…”

“…However, the radicals may be produced not only due to thermal dissociation but also thanks to vibrational excitation, which is typical for MWP and compounds like CO 2 , H 2 , and N 2 [48,49]. The direct influence of electrons or ions is rather negligible in the case of MWP due to low energy of the former [48] one and low concentration of the latter one [50]. More information considering MWP characteristics and its influence on tar compounds conversion may be found in the previous works [28,40].…”

Wettability of Polymeric Materials after Dielectric Barrier Discharge Atmospheric-pressure Plasma Jet Treatment

“…(8)(9)(10) Generally, because of the ease of chemical interaction, plasmas have found a variety of applications in many fields of science and technology. (11)(12)(13)(14)(15)(16)(17) The use of a plasma reactor with barrier discharge is most common in the technological treatment of drinking water, where ozone generated in discharges replaces toxic chlorine. Applications of dielectric barrier discharge (DBD) reactors include decontamination of water, gas, and soil.…”