•Developed a stripper-free blended amine based pre-combustion CO2 absorption process.•Performed a comparative techno-economic analysis reflecting carbon emission prices.•Conducted deep learning based ...multi-objective optimization using 1D-CNN and NSGA-Ⅱ.•Achieved a heat duty of 1.881GJ/tonCO2 for 90 % CO2 capture rate at lower than 370 K.•Suggested guidelines for various low-quality WHR scenarios according to temperatures.
With the emergence of the hydrogen economy, advanced CO2 capture technologies are essential for cost-effective H2 production until renewable-energy based H2 production technologies gains competitiveness. A novel stripper-free pre-combustion CO2 capture process, in which the stripper was replaced with a low-pressure (LP) flash column, was developed for cost-effective pre-combustion CO2 capture from H2-rich syngas at high pressure. The developed process could regenerate the blended N-methyldiethanolamine/piperazine (MDEA/PZ) solvent at relatively low temperature (<373.15 K). After the sensitivity analysis using key operating parameters, process optimization was performed by the deep learning-based surrogate models using non-dominated sorting genetic algorithm-II (NSGA-Ⅱ). The heat duty of 1.881GJ/tonCO2 was required at the optimal condition, but the required energy could be supplied through the utilization of a waste heat recovery (WHR) system because the regeneration was possible at low temperatures. Compared with advanced stripper-incorporated amine processes, the equivalent work of the developed process with WHR system using a heat source at 370 K was lowered by 50 % and more cost-effective (32.89$/tonCO2 at the discount rate of 10 %) from the economic analysis considering carbon emission price. The performance assessment of the stripper-free CO2 capture process provided design guidelines for effective CO2 capture from H2-rich syngas and emphasized the importance of CO2 capture unit in net-zero scenario.
•Studied CO2 absorption process using MDEA/PZ blended solvent for blue H2 production.•Suggested a novel solvent looping system of amine absorption process.•Performed techno-economic analysis and ...optimization of CO2 absorption process for SMR.•Achieved 0.622 and 0.751 GJ/ton CO2 of reboiler duty at 90% and 99% CO2 capture rate.•Achieved 99% CO2 capture rate at lower CO2 capture cost (42.44 USD/tonCO2) than 90%
Advanced CO2 capture processes for steam methane reforming that supplies large quantities of H2 to industries are critical for cost-effective blue H2 and CO2 production. In this study, a pre-combustion CO2 absorption process with a novel solvent looping system was developed to capture CO2 from SMR gas at a flow rate of 6946.5 kmol/h and 21 bar. A techno-economic analysis of the advanced absorption process using MDEA/PZ blended solvent was performed with respect to five key operating parameters. For 90 % and 99 % CO2 capture rates, the minimal reboiler duties were 0.622 and 0.751 GJ/CO2 ton, which were approximately 70 % lower than those of conventional post-combustion CO2 capture processes. Despite a significant increase in the CO2 capture rate (90 % to 99 %), the increase in energy consumption and OPEX was only 4 % while using the novel blended-solvent looping system through a low-pressure flash drum, resulting in a lower CO2 capture cost per ton at 99 % CO2 capture rate. The economic analysis suggested that the minimal CO2 capture cost decreased from 44.89 to 42.56 USD/CO2 ton as the capture rate increased. Furthermore, DNN models could predict the CAPEX and OPEX under higher than 98 % accuracy. DNN-based optimization with a multi-variable mutation of features revealed the optimum operating conditions for a minimum CO2 capture cost (42.44 USD/CO2 ton) over a short computational time (12 s). Thus, this study provides insights on the blended solvent and guidelines for a high-pressure CO2 absorption process with a solvent looping system for cost-effective blue H2 production.
•Studied pre-combustion CO2 capture process using blend amine to produce blue H2.•Performed an ANN model-based optimization of CO2 capture process for SMR.•Achieved 1.32 GJ/tonCO2 of reboiler duty at ...90% CO2 removal efficiency.•Over 90% CO2 removal efficiency led to a marginal increase in equivalent work.•Suggested valuable references for development of CO2 capture process in SMR.
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.
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•Advanced waste-heat recovery modules were proposed for efficient amine CO2 capture processes.•Primary modules and a CO2 capture process at 95% capture rate were validated.•The ...techno-economic assessment for various combination systems was conducted.•Cascade modules saved 12.27% ∼ 24.55% energy, 50% higher than single modules.•All modules were economically feasible and direct heat supply strategy was suggested.
A commercial-ready amine-based CO2 capture process (CCP) restricts its potential for industrial deployment at a high capture rate to achieve a net-zero carbon target due to its energy-intensive nature. This study aims to enhance the energy efficiency of a monoethanolamine (MEA)-based CCP, operating at a 95% capture rate, by developing advanced process modules that utilize low-grade waste heat. To establish a foundation for designing cascade modules that can recover energy from all available waste heat, the waste heat characteristics were analyzed, and the feasibility of four single modules was explored to recover the latent heat in a stripped gas. Subsequently, this study comparatively investigated the equivalent electrical works of the two designed cascade modules combined with lean vapor compression (LVC). A techno-analysis indicated that cascade modules provided outstanding energy-saving performance ranging from 12.27% to 24.55%, with an average improvement of 50% over single modules. Although the cascade modules combined with LVC showed similar energy-saving performances, higher robustness for equivalence factor (EF) and more energy-savings were discovered in the electricity generation and direct heat supply strategies, respectively. Economic analysis indicated that advanced process modules were economically feasible, with a savings-to-investment ratio (SIR) exceeding 1. The SIR and payback period (PBP) depended on EF and electricity prices. Significantly, the cascade module for direct heat supply emerged as the most appropriate in terms of both economic viability and energy-saving efficiency in amine-based CCPs, particularly at a higher EF.
