Most natural gas based petrochemical processes consist of catalytic reforming or partial oxidation units for producing synthesis gas. This research shows that it is possible to replace these units by the reaction of zinc oxide with methane, which produces metallic zinc and synthesis gas (CO + 2H(2)) simultaneously. Therefore, by combination of the metallurgical and petrochemical units, it is possible to eliminate the greenhouse gas emission from a conventional zinc production plant. On the other hand, synthesis gas from the ZnO + CH4 reaction can be used for making petrochemical products.In this work, the reaction of zinc oxide with methane was studied by thermogravimetry and online gas analysis with a mass spectrometer. The main goal of this article is the study on the nature of gaseous products and H-2/CO ratio of produced synthesis gas. Therefore, a basic method for quantitative gas analysis by mass spectrometer was introduced, and its accuracy was checked with the decomposition products of a standard material. Mass spectrometer results of the ZnO + CH4 reaction showed that synthesis gas with a HZ/CO ratio of about two is produced, which is very suitable for methanol production plants. Finally, the necessary kinetic parameters of this reaction for design of industrial plants were presented. (C) 2003 Elsevier Ltd. All rights reserved.