Amid a growing global demand for a clean energy source, hydrogen stands as a promising alternative to fossil fuels. That is because when burned, it does not emit greenhouse gases (GHG) or pollutants, making it an efficient source for the transportation sector, industrial projects, and power generation.
Meanwhile, hydrogen production remains a challenge. According to the Global Hydrogen Review 2024 by the International Energy Agency (IEA), global hydrogen demand reached 95 million tons in 2023, marking a steady increase from previous years. However, only 0.7 million tons of this hydrogen are produced from renewable energies, called green hydrogen.
The cost of green hydrogen production remains high, ranging from $3–8 per kilogram, compared to $1–2 per kilogram for fossil-based hydrogen, according to IEA’s report.
Hydrogen is primarily produced from natural gas through the Steam Methane Reforming (SMR) process. This process accounts for 50% of global hydrogen production. It results in a considerable amount of carbon emissions with 7.5–12 tons of carbon dioxide (CO₂) released for each ton of hydrogen produced.
Herein, most countries implemented carbon capture technologies to eliminate the resulting emissions as much as possible. This process is called blue hydrogen. It bridges the gap between fossil fuels and green hydrogen while leveraging existing infrastructure.
In a conventional blue hydrogen production process, amine-based chemical absorption methods are commonly employed to capture carbon dioxide emissions, but it faces challenges such as low capture efficiency and high energy demands.
Thus, researchers from South Korea proposed a novel system that integrates hydrogen production and liquefaction processes by introducing cryogenic carbon capture (CCC).
CCC is an advanced technology used in oil and gas operations to capture and remove CO₂ emissions. It works by cooling exhaust gases to extremely low temperatures around -120°C, causing CO₂ to solidify or liquefy, making it easier to separate and store.
CCC Integration in Blue Hydrogen Production
In this proposed system, the flue gas from the SMR process contains high concentrations of CO₂. Instead of sending the gas to an amine-based post-combustion capture system, it is compressed and cooled using seawater and drying units to remove excess moisture.
The dry and cooled gas is then directed into the CCC unit, which operates at cryogenic temperatures. CCC is directly connected to the hydrogen liquefaction process, taking advantage of its cold energy; thus, bringing CO₂ to low temperatures (about -120°C) to transition from a gas to a solid state.
The solidified CO₂ is mechanically separated from the remaining gases then compressed into high-purity liquid CO₂, which is easier to store, and transport compared to conventional high-pressure gaseous CO₂.
Consequently, the integrated system produced 50 tons per day of hydrogen reaching 99.99% purity via capturing 4.9 kilograms of carbon dioxide per one kilogram of hydrogen.
Furthermore, the system recorded a 27.5% reduction in overall energy consumption through integrating CCC with existing hydrogen liquefaction system.
Is it Economically Feasible?
The study analysis revealed that the total annualized cost for the proposed CCC-integrated blue hydrogen system is $66.14 million per year, which is 7.87 % lower than the $71.78 million per year for the conventional method.
A recent study found that the proposed system outperformed liquefied green hydrogen by 41.9% in economic performance.
As global industries seek sustainable hydrogen solutions, CCC-integrated blue hydrogen stands as a cost-effective and scalable pathway toward a cleaner energy future.
