Design and economic evaluation of a novel amine-based CO₂ capture process for SMR-based hydrogen production plants

Chemical absorption using amine solvents is the most commercially recognized technology to capture CO₂ from the SMR-based hydrogen production plant. Most studies focused on the use of PSA inlet or tail gas streams to remove CO₂ using MDEA solvent which is limited to about 60% of total plant CO₂ emitted. Whilst the capture of a flue gas stream has been reported via the MEA solvent to remove 90% CO₂ yet at relatively higher costs. A systematic investigation is required to identify the cost-effective use of the absorption processes when multiple positions are available for CO₂ capture. In this study, multiple cases of the CO₂ absorption process have been evaluated using MEA or MDEA solvents. Especially, a novel design for the simultaneous removal of CO₂ from the flue gas of a reformer and the PSA inlet gas stream is proposed and its techno-economic benefits are examined. For this purpose, the rate-based model has been implemented in the MATLAB environment to simulate the absorption process, whereas the solvent regeneration energy and the capital and operating costs of the main equipment have been estimated using the correlations taken from the literature. The new system based on the sequential reuse of MEA solvent for two streams is found to be the most economic process to remove 99% of total plant CO₂. The annualized cost of the proposed system is found 17.9% less in comparison to the best relevant conventional studied system of simultaneously removing CO₂ from the PSA inlet and reformer flue gas streams using MEA and MDEA solvents.