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Methanol is receiving considerable attention as an alternative fuel because of its potential role as a transitional option in mitigating greenhouse gas emissions and enabling the transition towards biofuels. Recycled methanol, produced using captured CO 2 or industrial by-product gases, emerges as an attractive alternative in South Korea, especially considering the excessive emissions from its energy and industrial sectors. However, assessing technological superiority amongst a range of alternatives remains challenging. This study aims to assess and compare various methanol production pathways utilizing captured CO 2 and by-product gases from steel industry within context of South Korea. The selected technologies are either currently in industrial use or pivotal for future industrial applications. A unified process design and assessment framework was employed to model and simulate eight technological conversion processes. These processes underwent evaluation based on key performance indicators, accompanied by comprehensive techno-economic and environmental life cycle assessments. Additionally, comparisons were made with conventional fossil-based methanol production, considering different hydrogen and electricity production routes. This study provides valuable insights into the viability of recycled methanol pathways in terms of process performance, economic and environmental feasibility and will facilitate the practical implementation of recycled methanol, contributing towards achieving carbon neutrality objectives. • Eight methanol production routes using waste carbon sources in South Korea are evaluated. • A unified process design framework is employed to model and simulate the processes. • Techno-economic and life cycle assessments uncover the optimal methanol production routes. • Various hydrogen and electricity pathways are considered to propose utilization strategies. • Hydrogen stands out the most crucial element in recycled methanol production. [ABSTRACT FROM AUTHOR]

• A data-driven optimization algorithm is developed for reliable PtX design. • Constraint of grid utilization prevents overuse of grid for sustainable production. • The trade-off between variations and means of performance indicators is revealed. • Results offer insights into design decision-making under renewable uncertainty. Designing a reliable power-to-X (PtX) process that uses renewable energy and grid electricity as backup power is challenging due to the uncertain nature of renewables and potential limits on grid usage. To address this challenge, this paper proposes a data-driven, reliability-based optimization approach for designing a grid-assisted PtX process and understanding how the uncertainty of time-series renewable profile affects its design and optimal sizing. This approach uses generative adversarial networks (GANs) to capture the complex patterns of renewables in temporal and spatial dimensions, rather than simply treating uncertainty as a probabilistic range as in conventional methods. The optimization considers both the mean and variance of production cost as objectives, while also taking into account the level of grid energy penetration as a probabilistic constraint through the reliability analysis. A power allocation and performance evaluation model is developed and used in conjunction with the optimization to assess uncertainty propagation through the PtX process and evaluate the impact of renewable uncertainty on process performance. A case study involving the production of methanol on Jeju Island in South Korea demonstrates how the mean and variance of production cost and other performance indicators can be balanced in the reliable design of PtX processes under renewable energy uncertainty, providing insights for decision-making in such situations. [ABSTRACT FROM AUTHOR]

This paper presents a thermochemical process design and techno-economic analysis for the production of methanol (MeOH) from Kenaf cultivated in Korea. The proposed process combines three main subsystems to allow for the processing of 2000 tons of kenaf a day: kenaf-to-syngas, syngas-to-MeOH, and a combined heat and power cycle. In the first subsystem, clean syngas is produced from kenaf via a two-step carbonization and steam gasification process. The clean syngas is then catalytically upgraded to MeOH using a commercial Cu/ZnO/Al 2 O 3 catalyst. The third subsystem allows for the generation of heat and electricity to close the energy balance by combusting the biomass residues. Energy analysis and optimization of the heat exchanger network allowed for all energy requirements to be satisfied internally, high overall energy efficiency (60.6%), and the selling of 3.3 MW of excess electricity. Furthermore, an economic feasibility analysis of the process showed that the minimum selling price of MeOH (99.9 wt%) was 0.413 US$/kgMeOH. Importantly, the process economics could be in the range of the market price with respect to incorporating different types of H 2 production technology into the process. • Green methanol production is a promising technology to convert Kenaf. • A process including a two-step of gasification and catalytic upgrading is designed. • Economic feasibility is evaluated by considering process scale. • Sensitivity analysis identify the relative significance of the major key parameters. [ABSTRACT FROM AUTHOR]