Co-gasification reactivity of petcoke and coal at high temperature

- Co-gasification reactivity of petcoke with coal was studied at high temperature.
- The reactivity of petcoke can be improved greatly by co-gasifying with coal.
- The synergistic effect is closely related to the minerals in coal but not coal rank.
- The Ca-/Fe-components is beneficial for gasification of petcoke even at 1400 °C.

Petcoke, as a byproduct of petroleum refinery process, can be used as feedstock of gasifiers due to its high carbon content and high calorific value. However, its low gasification reactivity and low ash content restrict its application to some gasifiers. In this work, experimental study on co-gasification reactivity of petcoke with coal under CO2 atmosphere was investigated in a drop-in-fixed-bed reactor in the temperature range of 1200-1400 °C. Produced CO was monitored continually using an online mass spectrometry to calculate the carbon conversion and gasification rate. The experimental results reveal that the gasification reactivity of petcoke can be improved greatly by co-gasifying with coals or by loading their ashes, even at temperatures higher than the ash fusion temperature. Both the coal and its ash can improve the gasification reactivity of petcoke. The synergistic effect is closely related to the composition of minerals in coal but not coal rank. The high content of active components such as Ca- and Fe- in coal or ash is beneficial for co-gasification. Some coals, however, are lack of these active components and with high Si- and Al-components content which may retard the gasification reaction. During co-gasification, the oldhamite (CaS), anhydrite (CaSO4) and magnetite (Fe3O4) have positive catalytic effect, while mulite (3Al2O3·2SiO2) has negative effect on gasification reaction at high temperature.