Yuchan Ahn

• Pohang University of Science and Technology

This work suggests an optimal strategy to sort and recycle plastic waste as a renewable energy resource with maximizing economic feasibility and mitigating environmental pollution. To derive the optimal sorting and recycling strategies of plastic waste, a novel optimization model is developed; it calculates the overall profit by subtracting the pro...

In this study, we suggested an optimal strategy to sort plastic waste to improve recycling efficiency considering economic feasibility. To derive the optimal sorting strategy, we developed a novel optimization model that considers the overall cost, which is sorting cost minus the revenue obtained by selling the recycling plastic from the sorting co...

This study develops an elemental sulfur recovery (ESR) process from sulfur dioxide (SO2) as a hazardous material removed from flue gas emitted at thermal coal-fired power plants with a carbonate melt flue gas desulfurization (CMFGD) process. The carbonyl sulfide (COS) generated as a byproduct after removing SO2 from flue gas using carbonate melt in...

To determine the optimal configuration of supply chain network for microalga-based biodiesel (MADSCN) considering uncertain values which influence the optimal strategies of microalga-based biodiesel production, we develop a two-stage stochastic model that considers the CO2 supply and biodiesel demand as uncertain parameters, which simultaneously in...

To determine the environmentally-benign process between the carbonate melt flue gas desulfurization (CMFGD) and the conventional process as the process of removing SO2 from the flue gas, in this paper, a life cycle assessment is applied using the data derived from the process simulation, including the heat integration methodology. The CMFGD process...

Sulfur dioxide (SO2) is a pollutant that is mainly emitted in thermal coal-fired power plants, and it causes air pollution, which is required to be removed since it adversely affects the atmosphere environment. This study presents a novel approach to remove SO2 using carbonate melt by designing a flue gas desulfurization (FGD) process that uses a c...

To optimize the configuration of a supply chain network for shale gas production (SGSCN), we develop a novel optimization model that considers ‘enhanced gas recovery by carbon dioxide (CO2) injection’ (EGR-CO2) technology, which simultaneously achieves decrease in net CO2 emissions. Then, the developed framework is used to identify the optimal SGSC...

Unconventional shale gas production in the United States has been largely improved due to the development of hydraulic fracturing technology and is projected to rapidly grow in the coming years. However, the acquisition of freshwater and management of flowback and produced (FP) water associated with hydraulic fracturing operation are two of the gre...

To investigate the effect of uncertainty in biodiesel production from microalgae, a supply chain network (SCN) of the process from cultivation of microalgae to distribution of biodiesel is developed using mixed-integer linear programming. Biodiesel demandis the crucial factor in the design of SCN, but is quite uncertain, so a stochastic approach th...

As water issues associated with hydraulic fracturing have received much attention, several optimization approaches have been developed for effective water management. However, most of them have not considered pumping schedules for hydraulic fracturing, which determines the productivity of a shale well as well as the total amount of freshwater requi...

This study develops a deterministic model for optimal design of an integrated network to determine the utility supply (US) and CO2 mitigation (CM) systems in consideration of technology to utilize CO2 as a raw material. The objective of the model is to minimize the expected total cost of an integrated network that satisfies US and CM demands of mul...

Formic acid (FA, HCOOH) using carbon dioxide (CO2) as a feedstock is sufficient to be synthesized on an industrial scale because it can be used as a carrier of hydrogen (H2) and as a precursor chemical in many chemical processes. Utilizing CO2 as an alternative carbon feedstock for FA production comes from reduction methods for greenhouse gas emiss...

Several approaches have been developed to design shale gas supply chain network (SGSCN) in an economically viable manner, but the connection between hydraulic fracture geometry, shale gas production, and wastewater recovery has not received much attention. Specifically, the final fracture geometry in unconventional reservoirs significantly affects...

A two-stage stochastic model is presented to develop the supply chain network and determine the optimal integrated network design by integrating CO2 mitigation and utility supply strategies with uncertain utility demand. The objective of this model is to decide the total network cost while meeting the utility demands and the targets of CO2 mitigati...

A novel strategy of large-scale 1,4-pentanediol (1,4-PDO) production derived from corn stover is presented based on catalytic conversion experiments. In this strategy, cellulose and hemicellulose of corn stover are catalytically converted to GVL by using corn stover derived GVL asa reaction solvent, and GVL asa reaction intermediate is then upgrade...

The optimum synthesis conditions for carbon nanotube (CNT) fibers were investigated using the Design of Experiment (DOE) technique. Direct spinning processes are governed by a variety of experimental factors: the methane flow rate, ferrocene flow rate, sulfur flow rate, hydrogen flow rate, water flow rate, and reaction temperature. The process was...

Many studies have developed mathematical programming models for optimal design of supply chains for agricultural or lingocellulosic biomass-derived bioethanol production. However, because of the shortcomings of using agricultural (food supply problems) and lingo-cellulosic biomass (low biomass availability and processing yield) as feedstock, use of...

To effectively reduce CO2, CO2 mitigation technologies should be employed tactically. This paper focuses on carbon capture and storage (CCS) as the most promising CO2 reduction technology and investigates how to establish CCS strategy suitably. We confirm a major part of the optimal strategy for CCS infrastructure planning through a literature revi...

A large number of research works were undertaken for the planning of sustainable electricity generation and CO2 mitigation (EGCM) infrastructure design under uncertainty. The typical methodologies assessed the performance of the problem under the variability of the uncertain parameters by optimizing the expected value of the objective function. Thi...