Refineries worldwide emit over 1.3 billion tons of CO2. These emissions are contributed by many parts of the refining operations.
Amongst these, hydrogen production units emit a significant portion. Hydrogen production could be either through steam methane reforming or through the oxidation of heavier oils (the former is probably the dominant one). Either way, significant amounts of CO2 are emitted from the process.
While CO2 capture at many points in a refinery might be needed over time, right now it is nice to see efforts to capture CO2 from the hydrogen production units. For instance, India's major oil refiner, Indian Oil aims to capture carbon dioxide from hydrogen generation units at its Koyali refinery in the Indian state of Gujarat for enhanced oil recovery at the nearby Gandhar oilfield.