Low-temperature and low-pressure non-oxidative activation of methane for upgrading heavy oil
It is highly desirable to upgrade viscous heavy oil, such as bitumen extracted from Canadian oil sand, to be transportable by pipeline. Conventionally, this is achieved by expensive catalytic hydrogenation under a hydrogen pressure of 15–20 MPa. In this study, it is reported that by using zinc and silver cation-modified HZSM-5 as the catalyst, methane can be activated at a low temperature of 380 °C and a pressure of 5 MPa to efficiently upgrade heavy oil, leading to the formation of partially upgraded crude oil which is more desirable for pipeline transportation and downstream refining. In addition, methane activation and its participation in the upgrading process were further evidenced by employing butylbenzene, styrene, and benzene as model compounds to represent heavy oil. This study opens a door for upgrading heavy oil with natural gas under fairly mild operation conditions instead of expensive hydrogen under rather stringent ones.