Study and design of a Hydrogen liquefaction process using ethane as refrigerant fluid

Hydrogen liquefaction is an essential process in cryogenics, facilitating the efficient storage and transport of hydrogen as a clean energy carrier. This study investigates the liquefaction of hydrogen at a flow rate of 100 kmol/h, with an energy consumption of 447.05 kW. The process relies on sophisticated equipment, including multi-stage compressors and expansion devices, which play key roles in cooling and compressing the hydrogen gas. One of the notable advantages of this system is the energy recovery achieved by an expansion device, which generates 262.1 kW, enhancing overall efficiency.The hydrogen compression stages use a multi-stage compressor that employs water as the primary coolant. With a flow rate of 389.4 kmol/h, water is chosen due to its high specific heat capacity and availability, making it an ideal coolant for this cryogenic process. Ethane, serving as a secondary refrigerant, operates at a flow rate of 32 kmol/h. Its non-corrosive and inert properties contribute to system durability, while a portion of the ethane is strategically recycled through heat exchangers to minimize consumption and optimize cooling efficiency. Hydrogen enters the system at 5×10⁵ Pa and 288 K, and is gradually cooled and compressed to 2×10⁵ Pa and 22.75 K, resulting in the final liquid hydrogen product. This significant temperature reduction, achieved through the combined cooling effects of water and ethane, is critical for the successful liquefaction of hydrogen. The optimized use of refrigerants and efficient energy recovery in the expansion stages reduce operational costs and enhance process sustainability.