Volume 43: Energy Transitions toward Carbon Neutrality: Part VI

Investigation on hydrogen production through in-situ heavy oil gasification process under different atmospheres conditions Tiantian Wang, Renbao Zhao, Hao Wang, Ningning Jiang, Xin Li, Haitao Ren, Ziqi Sun, Haitao Lv

Abstract

The in-situ production of hydrogen from hydrocarbon reservoirs offers a novel and cost-efficient approach, leveraging gasification and cracking reactions of fossil fuel sources. This study investigates the process of hydrogen production through heavy oil cracking under various atmospheric conditions, employing a kinetic cell apparatus. Additionally, this work pioneers the definition and computation method for hydrogen production efficiency, providing a quantitative framework to assess in-situ hydrogen generation performance during the later stages of heavy oil reservoir development. The outcomes of this research highlight that hydrogen generation transpires during the phases of pyrolysis and coke dehydrogenation reactions. Particularly noteworthy is that over 60% of the produced hydrogen originates from the coke dehydrogenation reaction range, prevailing at temperatures within 500–650 °C. In regard to the hydrogen production efficiency, when heavy oil samples are subjected to an air environment, it fluctuates within a range of 9.24–15.66%. This range is significantly lower compared to the nitrogen atmosphere, where efficiency varies from 12.26% to 28.65%. The inclusion of clay minerals serves as a natural catalyst, augmenting hydrogen generation rate and elevating efficiency to the peak value of 28.65%. This enhancement coincides with the maximum conversion rate of heavy oil, reaching 262.46 mL/g. Furthermore, the introduction of water substantially amplifies the overall mole count of hydrogen production, indicating its pivotal role in reducing the lower limit temperature for hydrogen generation from 400 °C to 300 °C.

Keywords Heavy oil, Hydrogen, Hydrogen production, In-situ gasification technology