Co-gasification of petroleum coke with coal at high temperature: Effects of blending ratio and the catalyst

• Co-gasification of petroleum coke and coal chars at high temperature is studied. • The gasification reactivity is largely increased at blending ratio of 1:2. • Inhibited effect shows in early stage but synergistic effect in late stage. • NaAlO 2 significantly increases the reactivity at carbon conversion rate above 0.2. • Catalyst co-gasification largely reduces the final temperature from 1460 °C to 1150 °C. In this study, co-gasification and catalytic co-gasification of petroleum coke with coal at high temperature are studied. The structural characteristics of high temperature petroleum coke and bituminous coal pyrolysis char are compared, and the effects of blending ratio on the gasification reactivity and synergy are explored. The effect of catalyst on the co-gasification is also investigated. The results show that, high temperature petroleum coke shows a smoother surface morphology and has a higher degree of graphitization than the coal char, as a result, the gasification reactivity of the former is much lower than the latter. The coal char gasification process shows only one reaction stage, while the high temperature petroleum coke has two significant stages. The gasification reactivity of the blends increases with the coal blending ratio, and the largest increment is obtained when high temperature petroleum coke and coal char is blended at 1:2. As the co-gasification proceeds with the temperature, it first shows an inhibition effect, then gradually a synergistic effect. The temperature at which the synergistic effect appears decreases with the coal blending ratio increasing. However, the co-gasification reaction rate and reactivity get worse at carbon conversion rate large than 0.5, leading to a longer reaction time. When catalytic co-gasification, NaAlO 2 significantly increases the reactivity at carbon conversion rate larger than 0.2, and the temperature needed to finish the gasification for high temperature petroleum coke is reduced from 1460 °C to 1150 °C.