Effects of mixture of CO₂ /CH₄ as pyrolysis atmosphere on pine wood pyrolysis products

The aim of the present work is to provide a preliminary support and research foundation for developing integrated technology of methane dry reforming and pine wood pyrolysis to produce high value chemicals and fuels. The chemical properties of bio-oil produced by pine wood pyrolysis under traditional N₂, H₂, CO₂, CH₄ atmospheres and mixtures of CH₄ and CO₂ were investigated. Experimental studies were conducted in a fixed bed reactor at a temperature of 500 °C. The results show that pine wood pyrolysis under mixtures of methane and CO₂ can promote bio-oil production (0.98% increase) compared with traditional pyrolysis (under N₂). GC-MS results show that the contents of phenols and sugars in bio-oil decreased, while the amount of alcohols, aldehydes, ketones, and furans increased. NMR spectroscopy provides additional support of the results. Results indicate that bio-oil can be used as a source of value-added chemicals. High proportions of CO were obtained in the gas products from pine wood pyrolysis under CH₄ and mixtures of CH₄ and CO₂. Finally, a possible reaction pathway of pine wood pyrolysis under mixtures of methane and CO₂ is proposed. Methane bi-reforming with CO₂ and steam from pine wood pyrolysis could promote the production of high value oxygen-containing chemicals during pine wood pyrolysis under mixtures of CH₄ and CO₂.