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.
•Experimental and techno-economic analyses of H2 from green NH3 are conducted.•As-developed Ru pellet catalysts showed high activity of 2827 h−1 at 450 °C.•Reforming efficiency of 83.6 % was achieved at 5 kWe scale with a COX free operation.•Minimum H2 selling price of 4 USD kg−1 is expected at industrial scales >10 MW.•CO2 emission can be reduced up to 95 %, compared to the conventional processes.
•H2 injection in the blast furnace is simulated by Rist operating diagram.•Economics and CO2 emission impacts of the renewable SOEC process are discussed.•The economic parity reaches at 2036 ∼ 2045 ...depending on the SOEC process maturity.•The annual CO2 emission reduction potential was estimated to be 1.16 MtCO2-eq.
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 kgCoke∙kgH2-1 depending on injection conditions and that 25 kgH2∙tHM-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 kgH2-1 in the present, but it is expected to be decreased to US$ 1.41 ∼ 4.04 kgH2-1 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 kgH2∙tHM-1 can reduce CO2 emission by 0.26 ∼ 0.32 tCO2-eq.∙tHM-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.
•Prognostics and health management of alkaline water electrolyzer is suggested.•Levelized cost of H2 and critical economic factors for green H2 are provided.•The economic feasibility according to ...voltage degradation is investigated.•An optimal replacement moment is suggested depending on capital expenditure.
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.
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Techno‐economic viability studies of employing a membrane reactor (MR) equipped with H2 separation membranes for methane steam reforming (MSR) were carried out for H2 production in Korea ...using HYSYS®, a well‐known chemical process simulator, including economic analysis based on itemized cost estimation and sensitivity analysis (SA). With the reaction kinetics for MSR reported by Xu and Froment, the effect of a wide range of H2 selectivity (10‐10,000) on the performance in an MR was investigated in this study. Because of the equilibrium shift owing to the Le Chatelier's principle, great performance of enhancement of methane conversion (
XCH4) and H2 yield and reaction temperature reduction was observed in an MR compared with a packed‐bed reactor (PBR). A window of a H2 selectivity from 100 to 300 is proposed as a new criterion for better MR performance of MSR depending on potential applications from in‐depth analysis of
XCH4 and H2 yield enhancements, a H2 purity, and temperature reduction. In addition, economic analysis to evaluate the feasibility of an MR technology for MSR was carried out focusing on a levelized cost of H2 based on itemized cost estimation of capital and operating costs as well as SA. Techno‐economic assessment showed 36.7% cost reduction in an MR compared with a PBR and revealed that this MR technology can be possibly opted for a cost‐competitive H2 production process for MSR.
For a sustainable hydrogen economy, large-scale transportation and storage of hydrogen becomes increasingly important. Typically, hydrogen is compressed or liquified, but both processes are energy ...intensive. Liquid organic hydrogen carriers (LOHCs) present a potential solution for mitigating these challenges while making use of the existing fossil fuel transportation infrastructure. Here, we present a process intensification strategy for improved LOHC dehydrogenation and an example of clean power generation using solid oxide fuel cells. Four LOHC candidates—ammonia, biphenyl-diphenylmethane eutectic mixture, N-phenylcarbazole, and N-ethylcarbazole—have been compared as stand-alone and integrated systems using comprehensive process simulation. “Temperature cascade” dehydrogenation was shown to increase the energy generated per unit mass (kWh/kg LOHC) by 1.3–2 times in an integrated system compared to stand-alone LOHC systems, thus providing a possibility for a positive impact on a LOHC-based hydrogen supply chain.
•Economic analysis was conducted for methanol synthesis through various pathways.•The economy of scale was confirmed for all pathways considered.•Lowest production cost was obtained through carbon ...dioxide electrolysis.•Environmental assessment was performed to identify carbon dioxide emission.•Economic and environmental feasibility of methanol synthesis was demonstrated.
Methanol is emerging as the carbon dioxide utilization technology and hydrogen carrier that can produce methanol using captured carbon dioxide and hydrogen. In this study, four cases were classified as methanol production according to which pathway was used to produce hydrogen: case 1 (steam methane reforming), case 2 (coal gasification), case 3 (water electrolysis), and case 4 (direct methanol production by carbon dioxide electrolysis). To figure out the best pathway in terms of economic and environmental perspectives, itemized cost estimation, sensitivity analysis, uncertainty analysis, and carbon footprint analysis were performed for four cases of methanol production with methanol production capacities of 1, 10, 20, and 50 ton d−1. From itemized cost estimation reflecting carbon footprint analysis results, respective unit methanol production costs of 3.66, 2.99, 3.69, and 0.55 $ kg−1 were obtained for methanol production capacity of 50 ton d−1. Compared to the unit methanol production cost (0.396 $ kg−1) from fossil fuel-based production, direct methanol production has become feasible than other cases. And, from sensitivity and uncertainty analysis, the cost of reactant and electricity were major economic parameters for cases 1–3 and case 4, respectively, and the possible unit methanol production cost ranges due to the cost fluctuations in future were investigated.
•Replacement of PEM water electrolysis with diverse degradation rate was considered.•Cash flow diagram was drawn considering degradation rate of PEM water electrolyzer.•Uncertainty analysis was ...performed considering renewable energy resources.•Environment impact assessment was carried out in terms of CO2 emission.•Quantified economic results for H2 from PEM water electrolysis were provided.
An environmental issue such as global warming causing series of disasters has been considered as a serious matter, which asks global cooperation, leading the Paris Agreement. As a result, considerable attention has been paid to H2 due to utilization and storage of renewable electricity expected to increase as time passes. A polymer membrane electrolyte (PEM) water electrolysis using renewable electricity generating from bioenergy, geothermal, onshore wind, etc., has been introduced to store electricity in form of H2. For preparing successful H2 society, an economic analysis was conducted considering PEM water electrolyzer cell replacement and renewable electricity resources to figure out economic feasibility. In this study, profitability analysis by drawing discounted cash flow diagram and uncertainty analysis using Monte-Carlo simulation based on itemized cost estimation result were carried out. The results presented that replacement preferred to occur at 2.20 V of max voltage of the PEM water electrolysis cell if electricity price is low and degradation rate is high. Furthermore, H2 selling price has been more influential factor to a net present value (NPV) than renewable electricity price and hydro and onshore wind energies are regarded as promising renewable electricity resources to achieve goal of H2 production cost. Moreover, CO2 footprint analysis was conducted to provide guidelines on the replacement of PEM water electrolysis in terms of environmental aspect.
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.
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•Modified Haber-Bosch process was covered for green NH3 production by considering diverse WE types.•Economic feasibility was conducted for green NH3 production to identify the most proper WE type.•The most appropriate WE type will be determined depending on unit electricity price.
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