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A deep-learning framework based on a graphical approach was developed to estimate Lithium-ion battery state-of-health covering three cathode materials using only partially-cycled profiles.

Techno-economic, carbon footprint, and scenario analyses of an ammonia-to-hydrogen-to-power system with different catalysts and fuels are conducted to evaluate its feasibility.

A techno-economic analysis (TEA) was conducted to evaluate the economic profitability and feasibility for a H2 energy storage system using an alkaline and a polymer electrolyte membrane water electrolysis for 1 MW water electrolysis operation. Many economic analysis methods such as itemized cost estimation, profitability analysis using a cumulative cash flow diagram, and uncertainty analysis employing a Monte-Carlo simulation method were utilized to perform a TEA. In particular, a renewable energy certificate (REC) was considered as an additional benefit of a renewable energy use. From itemized cost estimation, respective levelized costs of H2 of 7.21 and 9.19 $ kgH2−1 were obtained for both H2 energy storage systems in an alkaline and a polymer electrolyte membrane water electrolysis by considering current economy situation and therefore it is still difficult to be cost-competitive compared to a commercial H2 production cost. From profitability and uncertainty analysis results, an appropriate REC weight was confirmed in terms of discounted profitability criteria like a discounted payback period, a net present value, a present value ratio, and a discounted cash flow rate of return. In addition, a REC weight was affected on a net present value compared to a REC trading cost fluctuation.

Owing to the increasing demand for propylene, many propylene production pathways have been developed, such as naphtha catalytic cracking, olefin metathesis, propane dehydrogenation, and methanol to propylene (MTP) conversion. As environmental regulations become more stringent, green propylene should be explored to enhance sustainable production and reduce CO2 emissions. MTP conversion through CO2 hydrogenation (indirect MeOH synthesis) and CO2 electrolysis (direct MeOH synthesis) has been explored as a green propylene production pathway. To evaluate the possibility of green propylene production from technical, economic, and environmental perspectives, process simulation, economic analysis, and environmental assessment were performed for MTP conversion via indirect and direct methanol synthesis. Furthermore, the best alternative for green propylene production was determined via an analytic hierarchy process, considering technical, economic, and environmental aspects, at the same time, with different weighted values of each criterion, under uncertainty. Our results indicated that MTP via direct MeOH synthesis was superior in cases where the environmental impact is the most important, while MTP via indirect MeOH synthesis was the most appropriate alternative for green propylene production, with the technical and economic impacts being more critical than the environmental impacts.

Since hydrogen (H2) demand in the transportation field has increased as a result of efforts to reduce carbon emissions, the number of H2 refueling stations has been increasing as well. However, the transportation of H2 itself requires a lot of energy due to the low volumetric density of H2 necessitating energy-intensive processes of compression or liquefaction. In this context, ammonia (NH3) has been emerging as an efficient H2 carrier with several beneficial characteristics such as a large weight fraction of H2 (17.65%), and liquefaction at ambient temperature and moderate pressures which allows for the utilization of existing fossil fuel infrastructure. Thus, NH3 can be utilized as an H2 transport medium as well as a raw material for remote H2 refueling stations. In this study, a comparative 4E (energy, exergy, economic, and environmental) analysis of an H2 refueling station supplied from an on-site NH3 reforming using a packed bed reactor (PBR) and a membrane reactor (MR) is performed. Due to the higher H2 recovery in the MR, a greater H2 production rate is observed resulting in lower H2 production cost. Compared to the PBR, energy and exergy efficiency in the MR-based process are improved by 3.6%p and 2.7%p reaching 82.7% and 78.7%, respectively, and greenhouse gas emissions are reduced by ∼17% from 5.4 to 4.5 kgCO2-eq kgH2−1. The break-even price of H2 in the MR-based process at present is 8.1– 9.2 USD kgH2−1 (at scale of 900 kgH2 d−1) and the break-even points with the H2 selling price of 12.5 USD kg H2−1 are 7.8–8.9 y whereas the corresponding values are 9.4–10.5 USD kgH2−1 and 10.2–12.3 y in the process using the PBR. At an H2 selling price of 7.5 USD kgH2−1, most cases (90.6%) of the net present value in the MR-based process were positive in 2040 indicating an economically feasible process, while cases with lower H2 selling price (2.5 and 5.0 USD kgH2−1) were not deemed profitable under current technological level.

Real-time performance is important in rule-based continuous spatiotemporal query processing for risk analysis and decision making of target objects collected by sensors of combat vessels. The existing Rete algorithm, which creates a compiled node link structure for executing rules, is known to be the best. However, when a large number of rules are to be processed and the stream data to be performed are large, the Rete technique has an overhead of searching for rules to be bound. This paper proposes a hashing indexing technique for Rete nodes to the overhead of searching for spatiotemporal condition rules that must be bound when rules are expressed in a node link structure. A performance comparison evaluation experiment was conducted with Drool, which implemented the Rete method, and the method that implemented the hash index method presented in this paper. For performance measurement, processing time was measured for the change in the number of rules, the change in the number of objects, and the distribution of objects. The hash index method presented in this paper improved performance by at least 18% compared to Drool.

Accurate prediction of the hydrodynamic profile is important for circulating fluidized bed (CFB) reactor design and scale-up. Multiphase computational fluid dynamics (CFD) simulation with interphase momentum exchange is key to accurately predict the gas-solid profile along the height of the riser. The present work deals with the assessment of six different drag model capability to accurately predict the riser section axial solid holdup distribution in bench scale circulating fluidized bed. The difference between six drag model predictions were validated against the experiment data. Two-dimensional geometry, transient solver and Eulerian&ndash, Eulerian multiphase models were used. Six drag model simulation predictions were discussed with respect to axial and radial profile. The comparison between CFD simulation and experimental data shows that the Syamlal-O&rsquo, Brien, Gidaspow, Wen-Yu and Huilin-Gidaspow drag models were successfully able to predict the riser upper section solid holdup distribution with better accuracy, however unable to predict the solid holdup transition region. On the other hand, the Gibilaro model and Helland drag model were successfully able to predict the bottom dense region, but the upper section solid holdup distribution was overpredicted. The CFD simulation comparison of different drag model has clearly shown the limitation of the drag model to accurately predict overall axial heterogeneity with accuracy.

In this study, a techno-economic analysis for the bridging technology of hybrid methanol production based on tri-reforming of methane integrated with water electrolysis is performed. Focusing on the technical and economic parameters of three representative types of water electrolyzer (alkaline, proton exchange membrane, and solid oxide electrolysis), the process flow diagram for the targeted process is built and key economic parameters are confirmed. Based on the results of the simulation model and values of economic entries, itemized cost estimation reflecting the current status of water electrolyzers is conducted to evaluate the methanol production costs. Furthermore, the future production costs of methanol are estimated according to the projected values of system efficiencies, the lifetimes, and the future investment costs of three different water electrolyzer types. The results of methanol production costs in the present and the future are compared with the market prices of methanol in three different regions (U.S., Europe, and China) to verify the economic viability of the process. Considering the reported annual working hours of electrolyzers and the predicted decline of electricity prices generated from renewable energy sources such as photovoltaics and on-shore wind energy, operating hours of the plant and electricity prices for water electrolysis to be economically competitive are varied for more practical prediction for methanol production costs. In conclusion, the profitable operating conditions of the process to achieve a 20% margin in the regions in the present and the future are suggested concerning plant working hours and the levelized cost of electricity for each water electrolysis system.

Methanol steam reforming (MSR) in packed-bed reactors (PBRs) with membrane filters has emerged as promising hydrogen (H2) production system to overcome limitations of conventional membrane reactor (MR), which has H2 permeable membrane inside. In this study, techno-economic analysis is conducted based on results of process simulation using Aspen HYSYS® to assess technical and economic feasibility of MSR in systems of different number of PBRs and membrane filters and key economic parameters are presented. Also, effects of techno-economic parameters of reaction temperature, H2 permeance, and the number of PBRs and membrane filters on a unit H2 production cost are investigated, individually and comprehensively, in the ranges from 448 to 513 K, from 5 × 10 − 6 to 5 × 10 − 5 mol m−2 s−1 Pa−1, and one to four PBRs with zero to three membrane filters. Based on techno-economic analysis results, regressed function for the unit H2 production cost is achieved and optimization of operating conditions using GAMS© is conducted showing the minimum unit H2 production cost of 7.03 $ kgH2−1 and optimized conditions of 513 K, 5 × 10 − 5 mol m−2 s−1 Pa−1, and two PBRs with one membrane filter. In addition, to investigate environmental feasibility, carbon footprint analysis (CFA) is performed with comparing CO2 emissions according to techno-economic parameters.

The well-established Haber-Bosch (HB) process (industrial ammonia production) is a significant contributor to the world’s carbon emissions as it is a major consumer of natural gas as well as being energy-intensive in general. This work addresses the challenge of decarbonizing the HB process in a novel way as it, for the first time, presents a conceptual process integration with a supercritical CO2 Allam power cycle, therefore transforming gaseous CO2 emissions into a valuable side product in a form of liquid CO2. Detailed process design and flowsheet simulation using Aspen Plus ® was used as a basis for scale-up and techno-economic assessment of two cases (electrical grid dependent and independent). The results indicated that using this process design NH3 production reaches profitability at scales larger than 2 ton h−1 to 5.4 ton h−1 and at current global NH3 prices, the cost of manufacturing decrease, due to scale-up stabilizes at ∼ 30 ton h−1. Finally, this novel process integration achieves a significant reduction in gaseous CO2 emissions (compared to conventional HB process) of 68 % to 96 %, which indicates great potential for economically feasible green NH3.

Hydrogen produced by the electrochemical water splitting is essential for expanding and utilizing renewable power sources and establishing a sustainable energy society. As renewable energy network widely established, the produced hydrogen can be utilized by connecting the energy demand and energy supply. The proton exchange membrane (PEM) water electrolyser technology is one of the ideal candidates for direct coupling with renewable energy sources. In recent years, bench-scale experiments, and computational fluid dynamics (CFD) simulation-based approaches are used to accelerate the advances in performance and cost of the technology. We studied the influence of the key performance parameter of a PEM water electrolyser, and a single channel-based three-dimensional CFD model was developed. The PEM water electrolyser CFD model is validated against in-house experiments, where the developed model successfully predicts the current–voltage polarization curve. The developed CFD model is then used to analyze the influence of temperature, cathode pressure, membrane thickness, porous transport layer porosity and water feed rate. The main observation from the numerical study was discussed to provide insight into the factors affecting the PEM water electrolyser performance.

This study comprehensively investigates hydrogen production from green ammonia reforming, including synthesis of catalysts, reactor development, process integration, and techno-economic analysis. In-house developed Ru/La–Al2O3 pellet catalyst having perovskite structure showed high catalytic activity of 2827 h−1 at 450 °C and stability over 6700 h at 550 °C, exceeding the performance of the majority of powder catalysts reported in the literature. A scalable 12-faceted reactor adopting the as-produced catalyst was designed to enhance heat transfer, producing over 66 L min−1 of hydrogen with state-of-the-art ammonia reforming efficiency of 83.6 %. Near-zero CO2 emission of hydrogen extraction from green ammonia was demonstrated by-product gas recirculation as a combustion heat source. A techno-economic assessment was conducted for system scales from 10 kW to 10 MW, demonstrating the effect of reduced minimum hydrogen selling prices from 7.03 USD kg−1 at small modular scales to 3.98 USD kg−1 at larger industrial scales. Sensitivity analyses indicate that hydrogen selling prices may reduce even further (up to 50 %). The suggested hydrogen production route from green NH3 demonstrates superior CO2 reduction ranging from 78 % to 95 % in kg CO2 (kg H2)−1 compared to biomass gasification and steam methane reforming. These findings can be used as a basis for following economic and policy studies to further validate the effectiveness of the suggested system and process for H2 production from NH3.

Alkaline water electrolysis has been in the spotlight for green H2 production using electricity generated from renewable energy because of its high technology readiness level and low investment. However, commercialization of alkaline water electrolysis is challenging because of the low current density. Therefore, a techno-economic and environmental assessment was conducted for green H2 production by alkaline water electrolysis with experimental data from the advanced alkaline water electrolysis system of the Korea Institute of Energy Research (KIER) to identify the potential of this technology. Based on techno-economic analysis results, the stack cost and unit electricity price must be below 0.035 $ kWh−1 and 406 $ kW−1, respectively, to make this technology cost-competitive compared to the conventional H2 production method (

As NH3 has received extra attention expected to play a key role as an H2 carrier with desirable physical and chemical properties, H2 production via NH3 decomposition becomes a promising way to supply H2 in a cost-competitive and eco-friendly manner. In this study, life cycle techno-economic and carbon footprint analysis is conducted to investigate the feasibility of the NH3 decomposition process in terms of economic performance and CO2 emissions. In particular, the life cycle NH3 supply chain for H2 production is considered including production, transportation, and decomposition back to H2. Based on the classification of NH3 into three different types depending on how the chemical is produced, NH3 price and CO2 emissions are evaluated. In addition, using a commercial process simulator, the decomposition process is modeled and techno-economic analysis for the whole process for H2 production reveals that NH3 price is the most influential economic factor and the H2 production cost can compete with renewable-based H2 but it is still higher than fossil fuel-based H2 production. Moreover, H2 supply via NH3 decomposition is projected based on a domestic implementation plan in the Republic of Korea resulting in estimation of NH3 price, H2 production cost, and corresponding CO2 emissions in the future.

For utilization of valuable raw material of landfill gas (LFG), CH4 and CO2 which are the major chemical constituents in LFG can be reacted to produce H2 by so-called catalytic dry reforming of CH4 (CDR). In this study, the impact of applying a membrane reactor (MR) for CDR is investigated in terms of energy, economic, and environmental aspects (3E). Due to the intrinsic limitation of an MR being able to operate at lower temperature than the temperature of a conventional chemical reactor (packed-bed reactor, PBR), two different process configurations are invented for an MR and a PBR separately using a commercial process simulator. Based on different process configurations, comparative techno-economic analysis is conducted for an MR and a PBR at the same temperature as well as different temperature. It is identified that energy efficiency and productivity of the process are related to the operating temperature which directly affects variation of CH4 and CO2 conversion. However, it turns out that operating at higher temperature is not always better than lower temperature due to the additional CO2 emissions and fuel costs. Especially, it is revealed that an MR will overcome its low operating temperature and accomplishes economic viability compared to a PBR by developing its durability and permeability.

Synthetic natural gas (SNG) production from captured CO2 and H2 produced by water electrolysis using renewable energy is of increasing interest for low-carbon fuel production, CO2 utilization technology, and unstable renewable energy storage. In this study, the effect of voltage degradation in a water electrolyzer, a core technology for SNG production, on the unit production cost of SNG production and CO2 emissions, with different water electrolysis types such as alkaline electrolysis (AEL), proton exchange membrane electrolysis (PEMEL), and solid oxide electrolysis (SOEL), was identified through techno-economic and environmental assessment. In particular, the energy efficiency, unit production cost of SNG, and CO2 emissions were identified based on the change in the power consumption caused by voltage degradation. Moderate voltage loss results in a decrease in energy efficiency from 53.8% to 48.8% in AEL, 55.3% to 47.0% in PEMEL, and 76.3% to 51.2% in SOEL. Moreover, respective SNG unit production costs of 140.3–170.2 USD MWh−1, 157.5–203.1 USD MWh−1, and 153.1–353.5 USD MWh−1 for AEL, PEMEL, and SOEL, respectively, were obtained, showing an increase in SNG production cost due to the voltage degradation. Furthermore, total CO2 emissions for the SNG production process were investigated considering voltage degradation as well as electricity generation sources.

As many countries have tried to construct a hydrogen (H2) society to escape the conventional energy paradigm by using fossil fuels, methane pyrolysis (MP) has received a lot of attention owing to its ability to produce H2 with no CO2 emission. In this study, a techno-economic analysis including a process simulation, itemized cost estimation, and sensitivity and scenario analysis was conducted for the system of thermal-based and catalyst-based MP (TMP-S1 and CMP-S2), and the system with the additional H2 production processes of carbon (C) gasification and water–gas shift (WGS) reaction (TMPG-S3 and CMPG-S4). Based on the technical performance expressed by H2 and C production rate, the ratio of H2 combusted to supply the heat required and the ratio of reactants for the gasifier (C, Air, and water (H2O)), unit H2 production costs of USD 2.14, 3.66, 3.53, and 3.82 kgH2−1 from TMP-S1, CMP-S2, TMPG-S3, and CMPG-S4, respectively, were obtained at 40% H2 combusted and a reactants ratio for C-Air-H2O of 1:1:2. Moreover, trends of unit H2 production cost were obtained and key economic parameters of the MP reactor, reactant, and C selling price were represented by sensitivity analysis. In particular, economic competitiveness compared with commercialized H2 production methods was reported in the scenario analysis for the H2 production scale and C selling price.

In this study, various economic analysis methods, such as cost estimation considering experience rate, scenario analysis, and uncertainty analysis employing Monte-Carlo simulation method, were conducted for green NH3 production using modified Haber-Bosch process to select the appropriate water electrolysis (WE) type among alkaline WE(AWE), polymer electrolyte membrane WE (PWE), and solid oxide electrolysis cell (SOEC) and then evaluate the economic feasibility compared to conventional NH3 production. With the highest learning rate for each WE type and the lowest unit electricity price in 2045, the respective levelized costs of NH3 (LCOA) are 174.0, 283.1, and 327.3 $ ton−1 for AWE, PWE, and SOEC, respectively in the order of LCOEs from lowest to highest. Conversely, the LCOAs are 868.7, 999.9, and 709.6 $ ton−1 for AWE, PWE, and SOEC, respectively, when considering the highest learning rate and the highest unit electricity price of 0.06 $ kWh−1, owing to the lower energy consumption of SOEC compared to other WE technologies. Therefore, we confirm the considerable potential of SOEC for the production of green NH3 by the modified Haber-Bosch process.

With the growing concern about environmental issues including high CO2 emission, which is the main contributor to global warming resulting in climate change, CO2 utilization technologies have received much attention. Among diverse technologies, renewable methanol synthesis using H2 generated from the water electrolysis and the CO2 captured from various industrial processes as well as the atmosphere has received significant attention. In this context, the technical and economic feasibility analysis of renewable methanol synthesis was conducted in this study. Using a commercial process simulation program, Aspen HYSYS®, parametric studies were conducted to investigate the effects of diverse operating parameters, such as the reaction pressure, temperature, and H2/CO2 ratio, on the technical performance of this process. Under the optimum conditions of 100 bar and 493 K derived from thermodynamic studies, an economic analysis was performed to estimate the unit methanol production costs at different methanol production capacities using itemized cost estimation, sensitivity analysis, and predictive cost analysis. Predictive cost analysis was conducted to determine how the unit methanol production cost could be rendered reasonable compared to the existing one, which indicated that decreasing the renewable H2 production cost as well as increasing in the CO2 tax credit for a methanol production capacity of 100 ton per day would make the renewable methanol synthesis an economically feasible process.

Background: The negative pressure of the pleural cavity is critical to maintain lung expansion. However, the actual values of pleural pressure according to the phase of respiration after various types of pulmonary resection have not been well reported. The aim of this study was to measure the pleural pressure directly and to compare the results according to the extent of pulmonary resection. Methods: We manufactured a high-resolution digital manometer with which pleural pressure can be measured directly. A total of 43 patients who underwent thoracic surgery (lobectomy in 23, minimal resections in 20) were enrolled. The maximum, minimum, and mean pleural pressure was recorded during normal quiet breathing, forced breathing, and coughing, separately. Results: During normal quiet breathing, the average values of pleural pressure at end inspiration, end expiration, and the mean pleural pressure were −17.7, −7.0 and −11.2 cmH 2 O in lobectomy group, and −14.3, −4.6, −8.3 cmH 2 O in the minimal/no-resection group, respectively. The mean pleural pressure was significantly lower in lobectomy group compared to the minimal/no-resection group (P=0.026). During forced respiration, the same values were −44.0, −4.2 and −18.9 cmH 2 O in the lobectomy group, and −29.8, −0.1 and −12.7 cmH 2 O in the minimal/no-resection group. All of the pleural pressure values in lobectomy group were significantly lower compared to minimal/no-resection group (P=0.029, P=0.015, P=0.019, respectively). The maximal pressures during coughing were not statistically different between the two groups (38.4 vs . 34.4 cmH 2 O, P=0.687). Conclusions: We reported the actual pleural pressure changes according to the phase of respiration and type of surgery using a digital manometer. In lobectomy patients, the pleural pressure was highly negative compared to the minimal/no-resection group, especially during deep inspiration.