temperatures in the range of 800-900°C and significant water input, with a water footprint of approximately 4.5 kg/kg of H₂. As such, this route undermines the environmental advantage of HCNG by embedding resource-intensive hydrogen into the blend. Another environmentally friendly alternative to hydrogen from the SMR process is to use green hydrogen produced via water electrolysis using renewable electricity. While this route offers the theoretical advantage of zero upstream emissions, it comes with several challenges. Green hydrogen production is energy-intensive and currently priced significantly higher than grey hydrogen, making it economically challenging for widespread applications. Moreover, electrolysis systems require a reliable supply of renewable power and considerable water input, while also introducing operational complexity related to hydrogen storage, compression, and distribution. Alternatively, one approach is the use of methane decomposition or methane pyrolysis, in which methane is thermally split into hydrogen and solid carbon. While this method avoids direct CO₂ generation, it requires extremely high temperatures, typically above 1,000°C, and is prone to operational issues. Technologies such as molten-metal bubble columns have been explored in lab-scale demonstrations but have not reached commercial viability due to their complexity and cost. These technologies are often designed for centralised operation and tend to be capital- intensive, as they typically rely on significant utility requirements and costly infrastructure. This poses challenges for decentralised deployment, especially in applications like distributed low-carbon fuel distribution, localised power generation, or small industrial clusters. In addition, hydrogen blending into natural gas streams is a technically sensitive process, often requiring static blenders with proprietary designs to ensure uniform mixing and safe operation. These specialised systems are not only expensive but also have limited commercial availability, posing an additional barrier to widespread HCNG adoption. HP HCNG technology concept and chemistry HPCL R&D Centre has developed a novel, integrated process for the production of HCNG
HCNG
18% H + Methane
Natural gas
H
H
H
Carbon Nanotubes
H
Nano Graphite
Nano bres
Carbon Nano- materials
Carbon black Nanoparticles
Figure 2 HP HCNG technology process
and carbon nanotubes (CNTs) (see Figure 2 ). The technology is based on partial methane pyrolysis, in which hydrocarbon gases such as natural gas, methane, or compressed biogas are catalytically decomposed into hydrogen and solid carbon in a single-step reaction. This approach offers a carbon-neutral pathway for the production of HCNG, eliminating the need for external hydrogen supply or blending infrastructure. This technology, apart from being thermally mild, does not require any fresh water (unlike SMR and electrolyser processes) and produces zero direct CO₂ emissions. The HP HCNG process operates at significantly lower temperatures, typically ~600°C (compared to >1,000°C for thermal methane decomposition). This is made possible through the use of a proprietary, in-house-developed catalyst. More significantly, the solid carbon byproduct in HPCL’s process is an engineered coproduct in the form of carbon nanomaterials, including multi-walled carbon nanotubes (MWCNTs). Unlike conventional pyrolysis systems, where carbon deposits tend to form amorphous, low- value solids that contribute to catalyst fouling, the proprietary catalyst and reactor design employed in HP HCNG Technology promotes selective growth of structured carbon nanomaterials. These nanostructures exhibit high aspect ratios, favourable bulk density, and surface area properties that are consistent with industrial- grade carbon nanotubes used in applications ranging from polymer composites and coatings to energy storage, sensors, and specialty additives. The dual-product nature of the process, which yields both HCNG and carbon nanomaterials, makes it economically sustainable.
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