Electrified steam cracking for a carbon neutral ethylene production process: Techno-economic analysis, life cycle assessment, and analytic hierarchy process

Electrification is regarded as one of the solutions for decarbonization. To reduce the emissions of carbon dioxide from the steam cracking which is a conventional ethylene production process, the electrical heating furnace can be applied to the steam cracking called the electrified furnace. Here, to determine whether the electrified steam cracking is proper for carbon neutrality, the techno-economic analysis, life cycle assessment, and the analytic hierarchy process were implemented. The analysis was proceeded by the fourteen cases divided according to steam cracking, electrified steam cracking, and seven electricity generation methods. As a result, considering the technology development level, economic feasibility, and environmental impact, the best case was the steam cracking with hydropower, and the electrified steam cracking with hydropower, solar power, and wind power had high potential. As improving the technology development of the electrified furnace, the electrified steam cracking can be expected to become the proper ethylene production process to achieve carbon neutrality

Critical aspect of renewable syngas production for power-to-fuel via solid oxide electrolysis: Integrative assessment for potential renewable energy source

In this work, an integrative assessment of renewable syngas production by solid oxide electrolysis (SOE), which is also called co-electrolysis, was performed to investigate economic and environmental viability based on various renewable energy resources. First of all, economic analysis using itemized cost estimation, predictive cost assessment, and uncertainty analysis through Monte-Carlo simulation was carried out for estimating current and future levelized cost of syngas and possible cost ranges of the syngas production. From these analyses, the economic competitiveness of syngas production can be achieved with simultaneous cost reduction of major economic parameters, such as SOE system cost, CO2 price, and levelized cost of electricity. Furthermore, the low environmental potential of syngas production using some of the renewable energy sources was proved through life-cycle assessment. Finally, analytic hierarchy process was implemented to determine which one is the most feasible renewable energy in the technical, economic, and environmental aspects simultaneously. As a result, renewable syngas production coupling SOE and onshore wind electricity can bring considerable benefits in terms of CO2 utilization and other value-added chemical production

Prognostics and health management of alkaline water electrolyzer: Techno-economic analysis considering replacement moment

Recently, considerable attention has been paid to the installation of renewable energy capacity to mitigate global CO2 emissions. H2 produced using water electrolysis and renewable energy is regarded as a clean energy carrier, generating electricity without CO2 emissions, called ‘Green H2’. In this paper, a prognostics and health management model for an alkaline water electrolyzer was proposed to predict the load voltage on the electrolyzer to obtain the state of health information. The prognostics and health management model was developed by training historical operating data via machine learning models, support vector machine and gaussian process regression, showing the root mean square error of 1.28 × 10−3 and 8.03 × 10−6. In addition, a techno-economic analysis was performed for a green H2 production system, composed of 1 MW of photovoltaic plant and 1 MW of alkaline water electrolyzer, to provide economic insights and feasibility of the system. A levelized cost of H2 of $ 6.89 kgH2−1 was calculated and the potential to reach the levelized cost of H2 from steam methane reforming with carbon capture and storage was shown by considering the learning rate of the photovoltaic module and electrolyzer. Finally, the replacement of the alkaline water electrolyzer at around 10 years was preferred to increase the net present value from the green H2 production system when capital expenditure and replacement cost are low enough

What is the best scenario to utilize landfill gas? Quantitative and qualitative approaches for technical, economic, and environmental feasibility

To overcome the globally increasing trend in the generation of landfill gas (LFG), an environmentally harmful waste, which is derived from the huge amount of municipal solid waste, various investigations into the utilization of LFG have been actively conducted. In this study, an extensive investigation of the technical, economic, and environmental aspects for several scenarios of LFG utilization, in which LFG streams with different levels of CO2 capture (HG, MG, and LG) are utilized in the production of H-2 (HG-H-2, MG-H-2, and LG-H-2), electricity (HG-E, MG-E, and LG-E), and the valuable materials methanol (MeOH) (HG-MeOH and MG-MeOH), dimethyl ether (DME) (HG-DME and MG-DME), and formic acid (FA) (HG-FA and MG-FA), is presented. All the investigated scenarios are simulated using Aspen Plus (R), and the derived results are used in an itemized cost estimation to evaluate the process cost of each scenario. Profitability analysis reveals net present values of 24.9 and 18.4 M$ for HG-H-2 and HG-FA, and the subsequent scenario analysis indicates the significant effect of H-2 and product selling prices on economic feasibility. In addition, significant annualized CO2 emissions of 21 589 tonCO(2) years(-1) are obtained for MG-MeOH using integrative carbon footprint analysis, whereas LG-E exhibits the lowest emissions of 2610 tonCO(2) per years. Based on quantitative and qualitative analysis of the comprehensive feasibility of each scenario, the great potential of MG-FA to be a versatile utilization route and the environmental benefits of the LG-based utilization scenario are presented

What is the optimized cost for a used battery?: Economic analysis in case of energy storage system as 2nd life of battery

An electric vehicle is considered as one of the promising alternative transport due to its eco-friendly zero CO2 emissions. This trend causes a new environmental issue, Li-ion battery waste, and diverse plans for the used battery are suggested for preventing it. A stationary energy system connected to 1 MW photovoltaic was proposed as a repurposing strategy for the used battery. In addition, techno-economic analysis including itemized cost estimation, profitability analysis, and uncertainty analysis, was carried out to provide economic guidelines on what we need for the upcoming used battery era. Further, the optimized purchase cost for the used battery was figured out via a genetic algorithm. A levelized cost of electricity of 0.31 USD kWh-1 was obtained showing the PV cost as the most influential factor. The range of optimized purchase costs was 2,679-70,927, 3,786-100,234, and 5,747-152,162 USD according to 5, 10, and 20 years of the remaining lifetime of the used battery, respectively, and this cost varied depending on the target discounted payback period and subsidy. Finally, the repurposing of the used battery was still infeasible in terms of economic profit since 98.1%, 88.2%, and 75.2% were presented indicating a probability of negative purchase cost for the used battery. Our results show the needs of capital cost expenditure reduction via technological advancement to encourage the repurposing of the used battery

Simulation Model for Prediction of Gas Separation in Membrane Contactor Process

The purpose of this study is to establish a practical simulation model based on mass balance, mass transport equations and equilibrium equation between gas and liquid phases across a porous membrane in membrane contactor process in order to predict the separation behavior by the gassing process of gas mixture in membrane contactor. The established simulation model was verified by comparison between the simulated values and real process values in the separation of CH4/CO2 mixture, showing an excellent agreement between them. The parameter R-value in the model, which is a kind of the permeability of permeant across porous membrane, has been determined by fitting a numerical solution of the model equation to the experimental data to obtain a practical value of the parameter. A parametric study on the gassing process of N2/CO2 mixture in membrane contactor was made with the help of the practical simulation model to investigate the effects of operation parameters on separation performance and to characterize the separation behavior of membrane contactor process. A series of simulations of the separation of N2/CO2 mixture in membrane contactor were conducted, and the optimization on the membrane process was discussed to maximize the separation performance in terms of N2 recovery percent in retentate and CO2 permeation rate. It was observed from the analysis of the result of the simulation that liquid flow rate has a negative effect on N2 recovery percent in retentate but a positive effect on the separation of CO2, while R-value affects the separation performance in the other way. It is confirmed in this study that the developed simulation can be used as a tool to optimize the parameters, i.e., feed gas pressure, liquid flow rate and R-value to maximize the separation performance

Motivational and behavioral mechanisms underlying generalized health risking behaviors during the COVID-19 pandemic in smokers

Under the threat of public health challenges such as the recent COVID-19 pandemic, individual citizens’ active and cooperative participation in precautionary measures is crucial. Although non-compliance is recognized as a recurring problem, it remains unknown why some individuals tend to comply less than others and whether violations of preventive behaviors are observed consistently across different public health issues. To test our hypothesis that individuals would show consistent public health behavior transcending domains, we collected self-reports from two independent samples of participants (total N =2,983) on health risk beliefs and behavioral choices. Participants’ responses were collected in regard to two separate yet closely related public health issues: smoking and the COVID-19 pandemic. Our data reveal that on average, individuals’ beliefs and behaviors are consistent across different public health domains. In particular, smokers showed diminished compliance behaviors during the pandemic, which was mediated by their lower motives to protect public health. These results provide a psychological mechanism of how individuals' health risk behaviors are generalized across different public health domains that may explain why some individuals (here, current-smokers) are more prone to violate public health behaviors

Extractive-dividing-wall column and multi-objective optimizations of green entrainer-based ultra-high-purity recovery of methyl di glycol and N-Methyl-2-Pyrrolidone

The waste solvent is frequently generated from the processes that highly rely on solvents. Diethylene glycol monomethyl ether or methyl di glycols (MDG) and N-methyl-2-pyrrolidone (NMP) are representative valuable solvents used broadly and removed as waste solvents during the semiconductor material manufacturing processes. Although waste solvent can be practically retrieved by distillation, azeotropic waste solvent mixture only can be recovered by advanced distillation process. In this study, optimal extractive distillation and extractivedividing wall column are used to recover waste solvent. The process is optimized by multi-objective optimization using genetic algorithm by linking Aspen Plus & REG; and MATLAB. All optimal cases are compared in terms of energy, exergy, economic and environmental parameter. As a result, the potential energy, total annual cost saving and exergy efficiency for extractive dividing wall column are 26.29%, 24.15% and 21.02%, respectively. Exergy loss that is associated with the number of trays can be significantly reduced by optimization while exergy loss that is associated with remixing only can be significantly reduced by dividing-wall column. Further, multiobjective optimization using a genetic algorithm and a range of population provides various results that determine process selection

Outlook of industrial-scale green hydrogen production via a hybrid system of alkaline water electrolysis and energy storage system based on seasonal solar radiation

Hydrogen has been considered as a clean energy carrier by generating electricity via fuel cells without carbon dioxide emissions; however, in the current stage, most hydrogen is produced by a steam methane reforming, emitting carbon dioxide as a by product, together. In this context, a green hydrogen production system, which is consisted of water electrolysis and a renewable energy plant, should be expanded to prepare for the upcoming hydrogen society in the future. A techno-economic analysis is carried out for green hydrogen production based on seasonal solar radiation data in the case of the single and the hybrid system, which is designed as only alkaline water electrolyzer and a combination of alkaline water electrolyzer and energy storage system. In addition, a carbon footprint analysis is performed to quantify the carbon dioxide emissions for the proposed systems. And the optimal scale of alkaline water electrolyzer and energy storage system is figured out via a genetic algorithm considering a carbon tax on emitted carbon dioxide. Based on itemized cost estimation results, 6.55 and 6.88 USD kgH(2)(-1) of unit hydrogen production costs were obtained for the case of a hybrid and a single system, respectively. Further, the results present that the hybrid system is preferred when Li-ion battery costs decrease to under 79.67 USD kWh(-1). In addition, the capital cost is a crucial factor to figure out the optimized alkaline water electrolyzer scale and energy storage system capacity that set the optimized size is important to minimize the unit hydrogen production cost. Finally, the effort to reduce the capital cost to produce the green hydrogen is necessary when increasing trend of carbon dioxide tax is considered

Star PolyMOCs with Diverse Structures, Dynamics, and Functions by Three-Component Assembly

We report star polymer metal–organic cage (polyMOC) materials whose structures, mechanical properties, functionalities, and dynamics can all be precisely tailored through a simple three-component assembly strategy. The star polyMOC network is composed of tetra-arm star polymers functionalized with ligands on the chain ends, small molecule ligands, and palladium ions; polyMOCs are formed via metal–ligand coordination and thermal annealing. The ratio of small molecule ligands to polymer-bound ligands determines the connectivity of the MOC junctions and the network structure. The use of large M 12 L 24 MOCs enables great flexibility in tuning this ratio, which provides access to a rich spectrum of material properties including tunable moduli and relaxation dynamics.National Science Foundation (U.S.) (Award CHE-1334703