Post-combustion CO₂ capture by RVPSA in a large-scale steam reforming plant

Steam reforming (SR) of natural gas is the most widespread process to produce hydrogen. This paper presents a comprehensive simulation of an industrial plant for hydrogen production for the internal use in a refinery industrial complex based on the SR of different feedstocks. The reference plant is a 42,000 Nm³/h hydrogen production unit located in the South of Italy in the Refinery of Milazzo, Sicily. Hydrogen is produced from light gaseous hydrocarbons and purified by means of pressure swing adsorption technology. In the present work, a process simulation has been built on scientific basis and validated against field data at different feedstocks and operating conditions. The model correctly predicts the effect of relevant process parameters such as reformer feed pressure and temperature, steam to carbon ratio and plant load. In addition, the paper proposes the design of an industrial-scale rapid vacuum pressure swing adsorption (RVPSA) unit which was designed and simulated to capture carbon dioxide from the flue gas exiting the steam reformer. The RVPSA unit was integrated in the current plant enabling the concentration of CO₂ with a purity of 96.64%, an overall recovery of 90.84% and a specific energy consumption of 628.93 kJ/kg_CO2, thus meeting the requirements for transportation and geological storage. An energetic efficiency calculation was introduced to quantify the effectiveness of the hydrogen conversion process and to predict the effect of CO₂ capture and some process parameters to the overall H₂ production efficiency.