Research on the Stabilizer to Non-Catalytic Combustion Reaction in Oxidative Coupling of Methane

One of the most attractive methods for the direct conversion of methane to C₂ (ethylene and ethane) by oxidative coupling of methane (OCM) was proposed first by Keller and Bhasin in 1982. OCM was usually carried out at high temperature (above 600 °C), and the catalytic reaction and non-catalytic combustion reaction must be included in the temperature range higher than 600 °C. Therefore, it is very important to improve the catalytic reaction and inhibit the combustion reaction in catalytic and non-catalytic area. In this work, inert filler and metal mesh were selected as stabilizers to inhibit the combustion reaction. The reaction was operated in a microreactor over the temperature range of 400-800 °C, and the inner diameter and length of the microreactor were 10 mm and 530 mm. A simulated gas composed of 70.2% CH₄, 21.2% C₂H₄ and 8.6% C₂H₆ based on mol of carbon was used as feed gas. The flow rates of feed gas and O₂ were 52.5 mL/min and 17.5 mL/min, respectively. The result illustrated that the feed gas started combusting at 560 °C and O₂ was consumed completely at 650 °C in the case of using the empty microreactor. When the stabilizer was filled in the microreactor, the combustion reaction was inhibited evidently. No evident combustion reaction was observed until 700 °C when the reactor was filled with inert filler, and the temperature could reach 800 °C for metal mesh.