Post by Syed M Hadi Ali Zaidi

From Natural Gas to Blue Hydrogen: How We Built a Full Process Simulation from Scratch It started with a blank Aspen Plus flowsheet, a project brief, and one big question: Can we simulate an entire blue hydrogen production facility, from raw natural gas to captured CO₂, and make it behave like a real industrial plant? Our course project at UET Lahore challenged us to do exactly that. We developed a complete blue hydrogen production model representative of Pakistan's fertilizer sector, covering natural gas desulfurization, primary and secondary steam methane reforming, high- and low-temperature water-gas shift conversion, and MEA-based CO₂ capture. We modeled a natural gas feed of 100 kmol/hr with a steam-to-carbon ratio of 3. Different sections required different thermodynamic approaches, so we used Peng Robinson (PRMHV2) for the reforming side and Electrolyte NRTL for the MEA absorption system. The most challenging part was the CO₂ capture section and MEA recycle loop. The absorber and stripper were modeled using rate-based calculations, making convergence far more difficult than a conventional equilibrium-stage simulation. After many iterations and troubleshooting sessions, the entire process finally converged. The base case produced 393 kmol/hr of hydrogen at 87% purity, achieved 85% CO₂ capture efficiency, and closed the overall mass balance within 0.0015% error. Our energy analysis revealed that the primary reformer and MEA stripper reboiler accounted for nearly 90% of the plant's heating demand. We then performed a sensitivity analysis on seven operating variables. Increasing the reformer temperature to 1000°C and lowering the low-temperature shift reactor temperature to 180°C increased hydrogen production by 2.5%, reduced residual methane by 54%, and improved CO₂ recovery with minimal impact on operating costs. Using pinch analysis, we identified significant opportunities for heat recovery. An improved heat exchanger network recovered approximately 15 GJ/hr of thermal energy, reducing heating demand by 23.5% and cooling demand by 34%. A preliminary economic assessment also indicated strong project viability, suggesting that blue hydrogen can be commercially attractive when process optimization and carbon capture are effectively integrated. Beyond the technical results, this project showed us that blue hydrogen is not a future concept waiting to be invented. The chemistry is proven, the equipment exists, and the challenge lies in integrating carbon capture efficiently into existing industrial systems. A huge thanks to my teammates, Hamza Saif and Ahmad tariq, for their collaboration and dedication throughout the project. I would also like to express my sincere gratitude to Dr. AN Tabish for his continuous guidance, valuable insights, and support throughout the project. #BlueHydrogen #HydrogenEconomy #AspenPlus #ChemicalEngineering #ProcessEngineering #CO2Capture #EnergyTransition #UETLahore