Sub-Product

Refinery Off-Gas refers to the mixture of gases generated during the refining of crude oil. It is a by-product of various refinery processes, such as hydrotreating, catalytic reforming, and fluid catalytic cracking. The composition of refinery off-gas varies depending on the crude oil processed and the specific refining operations, but it typically includes components like methane, ethane, ethylene, hydrogen, butanes, butylenes, and other hydrocarbons^[1]. 

The following table shows a typical ROG composition^[2]:

Refinery off-gas can serve multiple purposes^[1]:

• When combusted within the refinery, it is classified as refinery fuel gas (RFG). This usage helps meet energy needs for process heaters and boilers.
• It can be used as feedstock in steam reforming of methane (SMR) units to produce hydrogen for hydrotreatment processes.
• Off-gas processing units can recover valuable products such as hydrogen, olefins (ethylene and propylene), and natural gas liquids (NGLs), adding economic value to refineries.

References

1. Perplexity Search, 11th Mar 2025, Proompt: "Please provide a definition of refinery off-gas".
2. Marcelo Tagliabue, Q1 2022, Refinery off-gas in hydrogen production, Digital Refining PTQ.