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How refineries can decarbonize operations through smart use of low-carbon hydrogen

The global energy landscape is diversifying, driven by a need to reduce emissions and help meet the goals of the Paris Agreement. Among the many sectors under analysis, refineries have a significant carbon footprint. According to the IEA, oil and gas operations account for around 15% of total energy-related emissions globally, the equivalent of 5.1 billion tons of greenhouse gas emissionsⁱ.

So, where do these emissions come from? A report from the World Resources Instituteⁱⁱ reported that the primary source of refinery emissions in the US in 2018 was stationary combustion (63%), while process emissions made up 31%, mainly from the fluid catalytic cracker (22%) and the steam methane reformer (9%). The good news is that decarbonization methods are available, with the introduction of low-carbon hydrogen into refineries offering a real and proven way to reduce these emissions. 

Hydrogen in refineries

Refineries are large industrial users of hydrogen, the majority of which is currently “gray” (sourced from fossil fuels without carbon capture). Hydrogen is essential in refineries for processes like hydrocracking, hydrotreating, sulfur removal, used to produce diesel, jet, gasoline and lubes. Moving from gray to low-carbon or “blue” hydrogen is therefore a great opportunity to cut emissions.

Traditionally, hydrogen is produced via steam methane reforming (SMR), which involves reacting natural gas with steam to produce hydrogen and carbon dioxide (CO₂). This process releases significant amounts of CO₂ emissions into the atmosphere. To decarbonize hydrogen production, one approach is to capture and sequester the CO₂ produced during SMR process, but it is very expensive to do from an SMR based hydrogen plant. This captured CO₂ can either be utilized for other purposes or stored underground to prevent its release into the atmosphere. This method produces what is known as low-carbon hydrogen. But this is just the beginning.

Process and utilization of low carbon

Low-carbon hydrogen produced using Topsoe's SynCOR™ is an advanced autothermal reforming (ATR) process – as opposed to SMR mentioned above – is notable for its exceptionally low carbon intensity (CI) when combined with carbon capture. This is achieved by capturing up to >99% of the CO₂ generated from natural gas (NG) from the process side. The steam-to-carbon ratio in the SynCOR™ process is only 0.6, which is three to five times lower than that of SMR or conventional ATR systems still in development.

A portion of the blue hydrogen produced in the SynCOR unit is utilized as fuel in a small furnace located upstream of the ATR unit. This ensures that the flue gas emitted from this furnace is practically carbon-free, further minimizing emissions.

The blue hydrogen produced is then deployed throughout the refinery, replacing all the gray hydrogen traditionally used in hydrotreating and hydrocracking units. It is also used as a decarbonized fuel across the refinery, ensuring zero direct carbon emissions from the refinery's numerous heaters and furnaces.

Additional efficiencies

SynCOR's feedstock is typically the refinery’s fuel gas, which is today used as fuels in the heaters and furnaces. Using this low-quality fuel gas as feedstock in SynCOR is a significant and unique benefit achievable by pretreating the fuels gas in Topsoe’s Fuel Gas Hydrotreating (FGH) solution. Without this pretreatment step the fuel gas would otherwise have to be flared, resulting in CO₂ emissions, because it would not be needed in the refining process.

Moreover, the heater in the SynCOR process is substantially smaller than that in a Steam Methane Reforming (SMR) plant. The heat required in the SynCOR process is primarily generated within the ATR unit, where NG is combusted with pure oxygen in a highly exothermic reaction. Consequently, only a small amount of additional heat is needed to bring the NG and steam to the necessary temperature at the ATR inlet, resulting in a much smaller heater in the SynCOR train.

In our SynCOR technology, nearly all the carbon from natural gas (NG) is captured and sequestered through CCS. This results in exceptionally low-carbon hydrogen. In conventional SMR plants, capturing CO₂ from flue gases is challenging due to low partial pressure, low CO₂ concentration and a higher process flow. However, in Topsoe’s advanced SynCOR technology, the CO₂ is captured in process, where it is more concentrated, at higher pressure and lower total flow, resulting it much lower CAPEX and OPEX cost to capture. This integration not only enhances the efficiency of CO₂ capture, but it also reduces the overall carbon footprint of the hydrogen production process.

The broader hydrogen ecosystem

If excess hydrogen is produced on site, refineries can create another revenue opportunity. In brief, hydrogen is difficult to store and transport due to its properties at ambient conditions and other characteristics. However, converting excess hydrogen into ammonia or methanol makes it practically to transport these chemicals as functional hydrogen carriers to be used as a decarbonized hydrogen for various industrial processes anywhere in the world. 

Ammonia is a well-established hydrogen carrier that can be easily transported and stored. It can be converted back to hydrogen at the destination using ammonia cracking technology, which Topsoe has been perfecting for over 30 years. Meanwhile, excess hydrogen can be combined with captured CO2 to produce methanol, which can be used as a maritime fuel or as a feedstock for producing synthetic aviation fuels. This not only provides an additional revenue stream but also helps decarbonize other sectors.

The path forward: Collaboration and continuous innovation

Decarbonizing refineries through hydrogen is not just about adopting new technologies but requires close collaboration between the technology providers and the refiners. Companies like Topsoe work closely with their customers from the initial brainstorming and study phases through to the deployment and operation of hydrogen SynCOR plants. This collaboration ensures that refineries can optimize their processes, reduce emissions, and remain competitive in a carbon-constrained world.

Hydrogen holds immense potential to revolutionize the refinery sector by significantly reducing its carbon footprint. Through advanced technologies like SynCOR, the use of refinery off-gases, and the integration of carbon capture systems, refineries can achieve substantial emissions reductions resulting in lower carbon intensity fossil-based transportation fuels. Furthermore, innovative solutions for hydrogen storage and utilization, such as converting it into ammonia or methanol, ensure that excess hydrogen can be effectively managed and utilized. By embracing these technologies and fostering collaborative partnerships, the refinery sector can make significant strides towards a more decarbonized future.

 ⁱIEA (2023), Emissions from Oil and Gas Operations in Net Zero Transitions, IEA, Paris https://www.iea.org/reports/emissions-from-oil-and-gas-operations-in-net-zero-transitions, Licence: CC BY 4.0

ⁱⁱWorld Resources Institute. Zachary Byrum, Carrie Dellesky (2021), A Low-Carbon Future in the US Depends on Decarbonizing Petroleum Refineries, https://www.wri.org/insights/technologies-decarbonize-petroleum-refineries