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Securing decarbonized economies for energy and commodities will require abundant and widely available green H

Industrial-scale upcycling of waste polyethylene terephthalate (PET) plastic into porous carbon globally for CO2 capture was verified as a multifunctional alternative to conventional CO2 absorption and plastic waste management technologies.

Microalgae have the potential to utilize the nutrients in livestock urine and manure (LUM) for the production of useful biomass, which can be used as a source of bioindustry. This study aims to evaluate the economic benefits of LUM feedstock that have not been clearly discussed before. Two types of photobioreactors were designed with a capacity of 200 m3 d-1. Using the experimental data, the economic feasibility of the suggested processes was evaluated via techno-economic analysis. Itemized cost estimation indicated that the submerged membrane photobioreactor has a lower unit production cost (5.4 $ to 5.1 $ kg−1) than the conventional photobioreactor system (14.6 $ to 13.8 $ kg−1). In addition, LUM-based growth is another good option for reducing the unit production cost of biomass. The revenues from lowering the cost of LUM treatment significantly contribute to enhancing the economic profitability, where the break-even prices were 1.18 $ m−3 (photobioreactor) and 0.98 $ m−3 (submerged membrane photobioreactor). Finally, this study provides several emerging suggestions to reduce microalgal biomass production costs.

As environmental problems become serious, many countries have been striving to change fossil-based energy to renewable and sustainable hydrogen energy. However, there are large capacity differences...

Environmental issue such as global warming caused serious natural disasters such as flood and drought due to CO2 emission. Global countries cooperate to address the global warming represented by Paris Agreement, which encouraged actions to restrict CO2 emission and global average temperature increase. H2 has been received more attention than before due to its eco-friendly property. Fuel cell and fuel cell electric vehicle (FCEV) are the widely used H2 application in terms of energy and transportation sector. However, most of the researches were carried out related to H2 supply chain. In hence, in this study, economic analysis considering total cost of ownership (TCO) of FCEV was conducted and correlation between TCO and market share of FCEV was figured out by drawing a regression curve. Finally, an optimization model was developed to obtain the optimal H2 fueling station arrangement model in case of 2022, 2030, and 2040 depending on learning rate (8, 13, and 18%). The $ 46,444.2 of TCO was computed considering three years of ownership length. In addition, 4.3, 31.7, and 94.0% of maker share in 2040 were reached in case of 8, 13, and 18% of learning rate, respectively. Finally, it was unveiled that H2 fueling station is preferred to construct equally in nation and the construction region will be shifted to a higher population density region as time passed.

Hydrogen (H2) is currently receiving significant attention as a sustainable energy carrier. Steam methane reforming (SMR) accounts for approximately 50% of H2 production methods worldwide. However, SMR is concern because of the prodigious carbon dioxide (CO2) emissions that have resulted in a global climate emergency. CO2 emissions remain, although some efforts have been made in a membrane reactor (MR) coupled with membranes to improve the H2 yield. A sorption-enhanced membrane reactor (SEMR) has been proposed as a next-generation process for simultaneous H2 production and CO2 capture. In this study, the thermodynamic and economic evaluation of SEMR were implemented using a process simulation, an itemized cost estimation, a sensitivity analysis (SA), and an uncertainty analysis (UA). The thermodynamic analysis results revealed that unit H2 production costs of 4.53, 1.98, and 3.04 $ kgH2−1 were obtained at 773 K for a conventional packed-bed reactor (PBR), a MR, and a SEMR, respectively. The SA results identified PSA as the most critical economic parameter for a unit H2 production cost for a PBR, whereas natural gas is determined to be the most influential parameter for a MR and a SEMR. The UA results from a Monte-Carlo simulation provided a broad range of unit H2 production costs, with 4.26–5.44 $ kgH2−1 for a PBR, 1.61–2.94 $ kgH2−1 for a MR, and 2.83–4.19 $ kgH2−1 for an SEMR. This indicates that using a SEMR for next-generation H2 production and CO2 capture is beneficial.

As the prices of photovoltaics and wind turbines continue to decrease, more renewable electricity-generating capacity is installed globally. While this is considered an integral part of a sustainable energy future by many nations, it also poses a significant strain on current electricity grids due to the inherent output variability of renewable electricity. This work addresses the challenge of renewable electricity surplus (RES) utilization with target-scaling of centralized power-to-gas (PtG) hydrogen production. Using the Republic of Korea as a case study, due to its ambitious plan of 2030 green hydrogen production capacity of 0.97 million tons year

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.

In this work, a comprehensive study of CO2 methanation by coupling process simulation, economic analysis, and life cycle assessment (LCA) was conducted to find out the most practicable pathway for green methane production in terms of technical, economic, and environmental aspects. For this work, different renewable energy resources, such as hydropower, wind power, and solar power, and water electrolysis, like alkaline water electrolysis (AWE) and proton-exchange membrane water electrolysis (PWE), leading to 6 scenarios for H2 production were considered. From the economic analysis in terms of itemized cost estimation, the levelized cost of methane (LCOM) for scenarios 1 to 6 was obtained as 0.108, 0.118, 0.144, 0.121, 0.132, and 0.159 $ kWh−1, respectively. In addition, from LCA, the respective quantified environmental impacts (i.e., CO2 emission) were obtained as 0.347, 0.813, 2.33, 0.537, 0.842, and 2.52 kg CO2-eq kg H2−1 for scenarios 1 to 6, respectively. And then, the analytic hierarchy process (AHP) was carried out to decide on the most appropriate renewable energy and water electrolysis based on different criteria of renewable energy capacity with Technology readiness level (TRL) of water electrolysis, LCOM, and CO2 emission for technical, economic, and environmental criteria, respectively. From this work, H2 production from AWE with wind power (i.e., scenario 2) was selected to be the best pathway for green methane production owing to the narrow priority range of 0.130–0.191. Furthermore, scenario 5 (i.e., PWE with wind power) was determined to be the second pathway with the same reason.

With the rising environmental concern, sustainable chemistry should be accomplished by considering technical, economic, and environmental factors that guarantee the successful implementation of new alternative products. Hence, we performed the integrated techno-economic and life cycle assessment for two-step solvothermal liquefaction (two-pot synthesis) and simplified solvothermal liquefaction (one-pot synthesis) based on experiment results. Based on the itemized cost estimation, the unit biopolyol production costs obtained from the two-pot synthesis and one-pot synthesis were 10.0 $ kg

The electrochemical N2 reduction reaction has attracted interest as a potential alternative to the Haber–Bosch process, but a significantly low conversion efficiency and a significantly low ammonia...

According to global trend of transition to a hydrogen society, needs for alternative hydrogen (H2) production methods have been on the rise. Among them, methanol steam reforming (MSR) in a membrane reactor (MR) has received a great attention due to its improved H2 yield and compact design. In this study, 3 types of economic analysis – itemized cost estimation, sensitivity analysis, and uncertainty analysis – and integrative carbon footprint analysis (iCFA) were carried out to investigate economic and environmental feasibility. Unit H2 production costs of MSR in a packed-bed reactor (PBR) and an MR for various H2 production capacities of 30, 100, 300, and 700 m3 h−1 and CO2 emission rates for both a PBR and an MR in H2 production capacity of 30 m3 h−1 were estimated. Through itemized cost estimation, unit H2 production costs of a PBR and an MR were obtained and scenario analysis was carried out to find a minimum H2 production cost. Sensitivity analysis was employed to identify key economic factors. In addition, comprehensive uncertainty analysis reflecting unpredictable fluctuation of key economic factors of reactant, labor, and natural gas obtained from sensitivity analysis was also performed for a PBR and an MR by varying them both simultaneously and individually. Through iCFA, lowered CO2 emission rates were obtained showing environmental benefit of MSR in an MR.

Integrative technoeconomic analysis (iTEA) with process simulation and economic analysis and integrative carbon footprint analysis (iCFA) of ethane steam reforming (ESR) for H2 production in a memb...

Economic uncertainty analysis of employing a membrane reactor (MR) equipped with H2O separation membranes for a synthetic natural gas (SNG) production as simultaneous power-to-gas and CO2 utilization technologies was carried out. Based on previously reported reaction kinetics, process simulation models were created for a conventional packed-bed reactor (PBR) and an MR. Deterministic economic analysis showed the unit SNG production cost of 1.67 $ kgSNG−1 in an MR compared to 1.82 $ kgSNG−1 in a PBR for a SNG production capacity of 1000 kg d−1, showing about 8% cost reductions in the MR. From sensitivity analysis, raw material and labor were identified as the key economic factors to affect a unit SNG production cost for all cases studied. Stochastic economic analysis using a Monte-Carlo simulation method provided better insights for economic-uncertainty associated with premature technology like a SNG production in an MR using H2O separation membranes by presenting a wide range of SNG production costs and their probability.

As an appropriate hydrogen supply system for high temperature polymer electrolyte membrane fuel cells, steam reforming of methanol (SRM) is proposed because reformate gas including low quality H2 with some impurities can be directly used as the fuel. In this study, we compare two SRM systems with and without the use of tail gas from pressure swing adsorption and comprehensive economic analysis is performed for the SRM process with the use of tail gas to estimate a unit H2 production cost (CUHP) based on historical data of natural gas and the CO2 allowance prices for Korea, Europe, Western Climate Initiative (WCI), and Regional Greenhouse Gas Initiative (RGGI). From deterministic economic analysis with a H2 production capacity of 700 m3 h−1, the CUHP values are 6.88 $ kgH2−1 for Korea, 6.84 $ kgH2−1 for Europe, 6.50 $ kgH2−1 for WCI, and 6.54 $ kgH2−1 for RGGI, respectively. Furthermore, additional two scenarios, pessimistic and optimistic ones (Scenario 1 and 2, respectively), are investigated to evaluate the current level of CUHP values for H2 production capacities from 30 to 700 m3 h−1. With a Monte-Carlo simulation method, stochastic economic analysis is carried out to predict the ranges of potential CUHP values for each region. The CUHP values for WCI and RGGI show the narrow distributions meaning lower change of CUHP; however, a wide range of distribution for Korea and Europe suggest that there is considerably higher variation, demonstrating the necessity of stochastic uncertainty analysis when assessing the economic feasibility.

In this paper, we report an integrated techno-economic analysis of glycerol steam reforming (GSR) targeting distributed H2 refueling stations for a H2 production capacity of 700 m3 h−1. A process simulation based on mass and energy balances was performed to identify the product yield at effect of temperature and water/glycerol ratio. The results show that temperature of 900 K and a water/glycerol ratio of 9 are optimal to techno-economically operate a GSR process. An economic analysis using itemized cost estimation, sensitivity analysis (SA), and profitability analysis (PA) was carried out to investigate the economic feasibility of GSR for distributed H2 refueling stations. The unit H2 production cost was 4.46 $ kgH2−1 at the optimum conditions identified in the process simulation, and the most influential economic key factor was the reactant from the SA. Meaningful economic indicators such as net present value, discounted payback period, present value ratio, and rate of return on investment were obtained from the PA through a discounted cash flow diagram. Moreover, a cumulative probability analysis based on an uncertainty analysis using a Monte-Carlo simulation method was applied to unit H2 production cost and B/C ratio calculations to quantify the risk of a proposed GSR process as premature technology providing crucial guidelines to decision-makers.

Computational fluid dynamics (CFD) studies have been carried out for CO2 reforming of methane in both a packed-bed reactor (PBR) and a membrane reactor (MR) with a heating tube as a heat source at the center of a reactor. The effect of a reactor geometry on the temperature and H2 and CH4 concentration profiles within a PBR and a MR have been investigated numerically by changing the distance of membranes from the center of a heating tube (Dcenter = radial distance between the center of the reactor and the center of the membrane) for a given heating tube temperature. The distances of the center of the membranes in a MR from the reactor center were 0.028 m, 0.03 m, 0.033 m, 0.035 m, 0.038 m, 0.04 m, 0.042 m, 0.044 m and 0.045 m. With the help of COMSOL Multiphysics® modeling software, it was possible to visualize temperature and concentration profiles both axially and radially. Interestingly, it was found that H2 enhancement is proportional to both Dcenter and the magnitude of the H2 flux. Further studies for the effect of a heating tube radius proposed an optimum radius for a maximum H2 yield enhancement in a MR. Consequently, it turned out that CFD studies can be used as a critical guideline for an efficient reactor design focusing on a reactor geometry in a MR for given conditions.

H2 is regarded as an alternative to current energy carriers without CO2 emission. To supplement traditional H2 production by fossil fuels, alkaline water electrolysis (AWE) is back in the spotlight. Unfortunately, H2 production by AWE is not economically practical yet compared with current fossil fuel H2 production methods. In this context, scenario analysis was performed in this study to find a suitable and reasonable scenario in which AWE is cost-competitive in terms of the levelized cost of H2 (LCOH) on the basis of diverse economic parameters such as the unit electricity price, the learning curve, and the automation level. From scenario analysis results, it is identified that the unit electricity price is the most effective economic factor to determine the LCOH followed by the learning curve and the automation level demonstrating that the introduction of surplus electricity, inevitably generated from renewable sources, can be very crucial for H2 production from AWE to be economically viable compared with the estimated LCOH of 1.25 USD per kg H2 in 2030 targeted by the United States Department of Energy. Most importantly, it can provide technical and economic guidelines on the basis of scenario analysis results. This can be very useful for decision makers to make economic and environmental policies in Korea and will result in entering the H2 economy society in the near future.

Process simulation and design as well as economic analysis were carried out to evaluate technical and economic feasibility of steam reforming of methanol in a membrane reactor (MR) for ultra-pure H2 production. Using a commercial process simulator, Aspen HYSYS®, comparative studies were conducted to investigate the effect of operating conditions including the H2 permeance (1 × 10−5 - 6 × 10−5 mol m−2 s−1 Pa−1), a H2O sweep gas flow rate (1–20 kmol h−1), and a reaction temperature (448–493 K) in a conventional packed-bed reactor (PBR) and the MR using a previously reported reaction kinetics. Improved performances such as methanol conversions and H2 yields were observed in the MR compared to the PBR and several design guidelines for the MR were obtained to develop H2 separation membranes with optimal H2 permeance and to select a suitable H2O sweep gas flow rate. In addition, economic analysis based on itemized cost estimations was conducted for a small-sized H2 fueling station by calculating a unit H2 production cost for both the PBR and the MR reflecting a current economic status in Korea. As a result, a cost saving of about 23% was obtained in the MR (7.24 $ kgH2−1) compared to the PBR (9.37 $ kgH2−1) confirming the benefit of employing the MR for ultra-pure H2 production.

Power-to-gas (P2G) technology has gained significant attention as one of the efficient methods to utilize surplus electricity inevitably produced from renewable sources. Coupled with the Korean government's efforts to increase the portion of renewable energy, P2G technology is considered as a promising candidate to produce H2 using surplus electricity for various industrial applications. Therefore, a comprehensive techno-economic analysis of H2 production from P2G technology using a high-pressure proton exchange membrane water electrolyzer (PWE) was conducted in this study in terms of itemized cost estimation and sensitivity analysis (SA). In particular, a stochastic approach was applied to reflect economic fluctuations possibly encountered in PWE, a premature technology. Respective H2 production costs of 4.33, 3.83, and 3.67 USD kg−1 were obtained for H2 production capacities of 300, 700, and 1000 m3 h−1, which are comparable to the current H2 market price of 5–6 USD kg−1 in Korea. Electricity was the most critical economic parameter in SA. Further studies using a Monte-Carlo simulation method of stochastic uncertainty analysis for a size factor's exponent, a major cost factor at scale-up, provide stochastic guidelines for P2G technology to be competitive and prove the economically attractive option of P2G technology using a high-pressure PWE for H2 production in Korea.

This study suggests the economic potential of biochar-based biodiesel production by conducting the techno-economic analysis. The itemized cost estimation was performed by categorizing biochar production facility and biodiesel conversion plants for 30,000 ton y−1 of biodiesel production capacity. The result of sensitivity analysis shows the methanol and waste cooking oil (WCO) costs are significantly sensitive to determine a unit biodiesel production cost. When the biodiesel selling price was 1.70 $ kg−1, the discounted payback period was varied from 1.91 (not discounted) to 2.06 years (10% discounted). In addition, the break-even price of biodiesel was calculated to 1.55 $ kg−1 when the discount rate was 10%. It means that this technology is to be feasible because of commercial diesel price (0.97 to 1.88 $ kg−1). The consideration of tax exemption and subsidy for biodiesel can be good option to supply WCO based energy production.

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.

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.

Spent coffee waste (SCW) is extremely attractive to be exploited and utilized as a material source for energy generation and chemical production. This study concerned bio-oil production via non-catalytic and catalytic fast pyrolysis using SCW in a bubbling fluidized-bed reactor (BFR). In particular, a comparative analysis of the quality of the bio-oil produced was conducted for non-catalytic (using silica sand as the bed material) and catalytic (using dolomite, HZSM-5, hematite, and magnetite as the catalyst) fast pyrolysis. Scale-up modeling confirmed using the experimental data was performed at a feed rate of 100 kg h−1 (1,000-fold capacity), which showed different orders in the quality of energy (hematite > magnetite > dolomite > HZSM-5 > silica, in order of energy from highest to lowest) owing to the realistic integration of the BFR with other components in plants, such as the combustor, compressor, and separator. Further, techno-economic analysis of scale-up system revealed that the unit production costs of bio-oil were 0.0151, 0.0034, 0.0143, 0.0095, and 0.0102 $ MJ−1 for silica, dolomite, HZSM-5, hematite, and magnetite, respectively (dolomite > hematite > magnetite > HZSM-5 > silica, in order of unit cost from lowest to highest). Among them, dolomite and hematite showed competitive unit production costs compared to the price of conventional crude oil (0.0098 $ MJ−1). The importance of coupling laboratory-scale experimental results with scale-up modeling and economic analysis has thus been demonstrated for practical feasibility studies of the SCW pyrolysis for bio-oil production.

We report techno-economic analysis of a biological desulfurization process to remove H2S and to produce sulfur from a landfill gas (2000 m3 h−1) produced in Korea. With a process simulation model d...

In this paper, we report economic feasibility studies focusing on profitability analysis of high pressure polymer electrolyte membrane (PEM) water electrolysis for distributed H2 refueling stations in Korea. From capital and operating costs, a unit H2 production cost of 6.24 $ kgH2−1 was obtained for a H2 capacity of 700 m3 h−1, which is equivalent to handling about 300 fuel cell electric vehicles. Based on cost estimations, profitability analysis using cash flow diagrams was performed to assess the economic feasibility of high pressure PEM water electrolysis and various key economic indicators like net present value (NPV), discounted payback period (DPBP), and present value ratio were obtained for both different discount rates and capacity factors. In conclusion, employment of high pressure PEM water electrolysis was found to be economically profitable showing reasonably high NPVs (16–52 MM$) and short DPBPs (4–7 years).

With the increased production of shale gas through a new drilling technology of hydraulic fracturing, much attention has been directed to various utilization methods for ethane accounting for about 7% of shale gas. As an efficient utilization method for ethane, ethane steam reforming in a membrane reactor is proposed in this paper to provide improved reactant conversions and product yields thus leading to a reduced operating temperature. To assess techno-economic feasibility of ethane steam reforming in a membrane reactor, parametric studies focusing on a H2 selectivity and economic analysis predicting profitability from cash flow diagrams based on a purified hydrogen in Korea were performed simultaneously providing very useful design and economic guidelines to implement a membrane reactor for ethane steam reforming.

With the aim of producing hydrogen at low cost and with a high conversion efficiency, steam methane reforming (SMR) was carried out under moderate operating conditions in a Pd-based composite membrane reactor packed with a commercial Ru/Al2O3 catalyst. A Pd-based composite membrane with a thickness of 4–5 μm was prepared on a tubular stainless steel support (diameter of 12.7 mm, length of 450 mm) using electroless plating (ELP). The Pd-based composite membrane had a hydrogen permeance of 2.4 × 10−3 mol m−1 s−1 Pa−0.5 and an H2/N2 selectivity of 618 at a temperature of 823 K and a pressure difference of 10.1 kPa. The SMR test was conducted at 823 K with a steam-to-carbon ratio of 3.0 and gas hourly space velocity of 1000 h−1; increasing the pressure difference resulted in enhanced methane conversion, which reached 82% at a pressure difference of 912 kPa. To propose a guideline for membrane design, a process simulation was conducted for conversion enhancement as a function of pressure difference using Aspen HYSYS®. A stability test for SMR was conducted for ∼120 h; the methane conversion, hydrogen production rate, and gas composition were monitored. During the SMR test, the carbon monoxide concentration in the total reformed stream was

In this paper, we report techno-economic analysis for CO2 reforming of a medium-grade landfill gas in a membrane reactor (MR) for a H2 production capacity of 7 m3 h−1 in Korea. Parametric studies for the effect of key operating conditions like a H2 permeance, a H2O sweep gas flow rate, and temperature on the performance in a conventional packed-bed reactor (PBR) and a MR were conducted using Aspen HYSYS®, a commercial process simulator. Based on process simulation studies, economic analysis was carried out to find a unit H2 production cost for both a PBR and a MR. Respective unit H2 production costs of 9.72 and 6.46 $ kgH2−1 were obtained for a PBR and a MR showing about 34% reduction in the MR. Sensitivity analysis was employed to identify key economic factors to determine a unit H2 production cost with labor the most influential factor for both reactors. Probability analysis (PA) was performed with influential factors based on a Monte-Carlo simulation method as uncertainty analysis and a cumulative probability (CP) curve was created for a PBR and a MR under various discount rates from 2 to 10% and key factor ranges from ±10 to ±40%. PA using stochastic approach provided a wide range of a unit H2 production cost coupled with its probability and a critical CP value at which the effect of key factor range on a unit H2 production cost was reversed.

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 (

The steel sector is one of the most carbon-intensive industries, and the sustainable strategies to reduce CO2 emission on integrated mill plants are discussed continuously. By renewable H2 utilization on blast furnace (BF), it is expected to achieve both sustainable operation and CO2 emission reduction. We evaluate the application of the solid oxide electrolysis cell (SOEC) process as a source of H2 for use as an alternative to CO as the reductant in a BF. We mathematically formulated a BF model and developed an integrated BF-SOEC process. We performed techno-economic analysis to suggest the maximum H2 injection for the technical aspect, and demonstrated the process’ economic viability, considering the learning-by-doing effects on the price of the SOEC system. We also estimated the net reduction of global warming potentials and carbon intensity. Our findings showed that the coke replacement ratio ranged from 0.255 ∼ 0.334 k g C o k e ∙ k g H 2 - 1 depending on injection conditions and that 25 k g H 2 ∙ t H M - 1 was an acceptable maximum injection rate within the stable range of BF operating indexes. We calculated H2 production cost to be US$ 8.84 ∼ 8.88 k g H 2 - 1 in the present, but it is expected to be decreased to US$ 1.41 ∼ 4.04 k g H 2 - 1 by 2050. Economic parity with the existing BF process will be reached between the years 2036 and 2045, depending on the maturity of the SOEC process. Injection of 25 k g H 2 ∙ t H M - 1 can reduce CO2 emission by 0.26 ∼ 0.32 t C O 2 - e q . ∙ t H M - 1 We expect that this sustainable strategy to reduce CO2 emission from integrated mill plants will widen applications of H2 utilization in BFs if the economic efficiency of SOEC systems can be increased.

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.