Theoretical study of partial oxidation of methane by non-equilibrium oxygen plasma to produce hydrogen rich syngas

• Published in: International journal of hydrogen energy Vol. 40; no. 32; pp. 9872 - 9884
• Main Authors: Starik, A.M., Kuleshov, P.S., Loukhovitski, B.I., Titova, N.S.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 24-08-2015
• Subjects: Ignition; Methane; Oxygen plasma; Partial oxidation; Reaction mechanism; Syngas production; Methane; Reaction mechanism; Oxygen plasma; Partial oxidation; Syngas production; Ignition
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2015.06.066

Modeling study of the partial oxidation of methane and methane-steam blend in a model flow reactor with given length in order to produce hydrogen rich syngas via activation of oxygen by specially arranged electric discharge is presented. It has been shown that the minor length of methane and methane-steam conversion into syngas is achieved at reduced electric field of 10 Td, when excited O2(a1Δg) and O2(b1Σg+) molecules are preferably generated in a discharge. The major yield of syngas due to methane partial oxidation takes place at CH4/O2 equivalence ratio ϕ = 3 and can be as large as 89%, whereas the greatest ratio of H2 mole fraction to CO one in syngas can be achieved at ϕ = 4, when the yield of syngas is notably smaller ∼69–76%. The addition of steam to methane delays the conversion process and does not allow increasing the syngas mole fraction and H2/CO ratio significantly at the flow reactor exit. The estimates of energy efficiency of the process showed that the major value of energy returned on energy invested is achieved for the plasma-chemical approach based on methane partial oxidation or a combination of partial oxidation with steam conversion.
•Partial oxidation and steam conversion of methane to syngas by plasma is studied.•Minor conversion length is achieved when singlet oxygen is generated in discharge.•The major yield of syngas at the reactor exit occurs at ϕ = 3 and it is equal to 89%.•The H2/CO molar ratio at the reactor exit at ϕ = 4 can be greater than its equilibrium value.•Major value of EREI is achieved for methane partial oxidation with ϕ = 3.