Hamid Abbasi - Department of Chemical Engineering, Amirkabir University of Technology, Tehran, Iran.
Mohammad Mahdi Moshrefi - Department of Chemical Engineering, Amirkabir University of Technology, Tehran, Iran.
Fariborz Rashidi - Department of Chemical Engineering, Amirkabir University of Technology, Tehran, Iran.

Formaldehyde is in great demand either as source or as intermediate for petrochemical industries. Conventional technology for the conversion of methane to formaldehyde involves three costly and complex steps; catalytic reforming of methane to syngas, catalytic conversion of syngas to methanol and the oxidation of methanol to formaldehyde. This process suffer from several aspects; a) high maintenance of catalyst, b) syngas step production which associated more than 60 % of capital costs and c) only economically feasible for a large scale of natural gas source. Non-catalytic and single step conversion of methane to formaldehyde is an attracting option to economically convert natural gas resources, specifically small-scale ones, integrally. In this study, mathematical model in an annular flow micro reactor system is constructed and sixty six non- differential equations solved using finite element method (FEM) by COMSOL Multiphysics 5.3a and good agreement is obtained when the model results are compared with experimental data. Impacts of several operating parameters including temperature, residence time and oxygen/methane ratio were analyzed. The main objective of this concise study is describing the concept of non-catalytic and single step conversion of methane to formaldehyde and assessment effective parameters on this process.

Methane, Formaldehyde, Catalyst free, Micro reactor, Yield