Pre-combustion CO₂ capture using amine-based absorption process for blue H₂ production from steam methane reformer

A novel pre-combustion CO₂ capture process using methyl diethanolamine with piperazine (MDEA/PZ) was investigated for the production of blue H₂ from a steam methane reformer (SMR). A sensitivity analysis was performed at various operating parameters (such as MDEA or PZ concentration, flash drum pressure, CO₂ loading in a lean-amine solvent, and CO₂ removal efficiency) using a validated rate-based model. The energy consumption to capture CO₂ from SMR gas at 21 bar was evaluated, including the compression energy (up to 30 bar) for the dehydration of captured CO₂. For 90% and 95% CO₂ removal efficiency, reboiler duties were 1.318 GJ/tonCO₂ and 1.364 GJ/tonCO₂, and CO₂ compression works were 11.673 kW/molCO₂ and 11.615 kW/molCO₂. The results indicated more than 40% lower reboiler duty than the energy consumption of conventional CO₂ capture processes in post-combustion. Subsequently, artificial neural network model (ANN)-based optimization using the differential evolution method was performed. The developed ANN-based optimization suggested the possibility of additional 0.3 % reduction in the equivalent work at a low computational cost. The results indicated that the developed pre-combustion CO₂ capture for a SMR was highly competitive in industrial applications. Moreover, the H₂ mixture produced at 21 bar is beneficial for a H₂ recovery unit because of no need for additional compression energy. Therefore, the MDEA/PZ-based absorption process can effectively contribute to centralized or semi-central blue H₂ production from a SMR. This study provides a guideline for the feasible optimization and control of the CO₂ absorption process at high feed pressures.