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Temperature profiles along the reactor length of (a) adiabatic converter, 105 steam raising converter, 126 Methanol Casale IMC, 142 and isothermal converter (idealized), (b) Mitsubishi Superconverter, 143 (c) Lurgi MegaMethanol. 99
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The conversion of H2 and CO2 to liquid fuels via Power-to-Liquid (PtL) processes is gaining attention. With their higher energy densities compared to gases, the use of synthetic liquid fuels is particularly interesting in hard-to-abate sectors for which decarbonisation is difficult. However, PtL poses new challenges for the synthesis: away from syn...
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... rate by low outlet temperatures and a good energy efficiency by internal heat recovery. 26 A summary of the main commercial reactor types (Johnson Matthey Davy Technologies is missing due to scarce information) 132 is given in Table 7. Respective simplified reactor schemes are illustrated in Fig. 6 and detailed temperature profiles are shown in Fig. ...
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... reactor and a steam-raising tubular reactor by using double-pipe tubes in a boiling water vessel (or even triple pipes). 140 The feed gas first flows upwards through the inner tube before passing downwards through the outer tube which is filled with catalyst. 141 Preheating the feed gas in the inner tube results in a specific temperature profile (Fig. 7b) along the catalyst bed with a high temperature (maximum 250-260 1C) near the inlet that gradually declines towards the outlet (240-250 1C) closely following the maximum reaction rate line. 140 The Methanol Casale (pseudo) Isothermal Methanol Converter (IMC) is cooled by feed gas, boiling water or a combination of both inside hollow ...
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... Methanol Converter (IMC) is cooled by feed gas, boiling water or a combination of both inside hollow plates which are immersed in the catalyst bed (Fig. 6e). Independent temperature control of different parts of the plates is possible by adjusting the cooling fluid flow at different heights. 144 Thereby the quasi-isothermal temperature profile ( Fig. 7a.3) can be modified to fit the maximum reaction rate curve. 128,145 For capacities up to 2000 t per d axial flow of the process gas is preferred. 146 For larger capacities up to 7000-10 000 t per d in a single converter, axial-radial flow configuration is used due to the lower pressure drop. [146][147][148] Another concept which is ...
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... in a tubular reactor cooled in counter-current (or co-current) flow with the cold feed gas for the first reactor. 149 This has the advantage that only a small feed gas preheater (up to about 130 1C) is required which results in a decreasing temperature along the reaction path maintaining the equilibrium driving force for methanol production (Fig. ...
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... operating temperatures improve the reaction kinetics (at the risk of by-product formation) while low temperatures at the reactor outlet are favoured by the equilibrium, maximising the overall conversion. Detailed temperature profiles of exemplary converters are given in Fig. 7. As seen, the Superconverter design as well as the MegaMethanol process achieve relatively low temperatures at the outlet and only a small preheater is necessary due to the internal preheating of the feed gas. The heat transfer coefficient and the peak catalyst temperature determine the steam pressure of the cooled reactors, which is ...
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... rate by low outlet temperatures and a good energy efficiency by internal heat recovery. 26 A summary of the main commercial reactor types (Johnson Matthey Davy Technologies is missing due to scarce information) 132 is given in Table 7. Respective simplified reactor schemes are illustrated in Fig. 6 and detailed temperature profiles are shown in Fig. ...
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... reactor and a steam-raising tubular reactor by using double-pipe tubes in a boiling water vessel (or even triple pipes). 140 The feed gas first flows upwards through the inner tube before passing downwards through the outer tube which is filled with catalyst. 141 Preheating the feed gas in the inner tube results in a specific temperature profile (Fig. 7b) along the catalyst bed with a high temperature (maximum 250-260 1C) near the inlet that gradually declines towards the outlet (240-250 1C) closely following the maximum reaction rate line. 140 The Methanol Casale (pseudo) Isothermal Methanol Converter (IMC) is cooled by feed gas, boiling water or a combination of both inside hollow ...
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... Methanol Converter (IMC) is cooled by feed gas, boiling water or a combination of both inside hollow plates which are immersed in the catalyst bed (Fig. 6e). Independent temperature control of different parts of the plates is possible by adjusting the cooling fluid flow at different heights. 144 Thereby the quasi-isothermal temperature profile ( Fig. 7a.3) can be modified to fit the maximum reaction rate curve. 128,145 For capacities up to 2000 t per d axial flow of the process gas is preferred. 146 For larger capacities up to 7000-10 000 t per d in a single converter, axial-radial flow configuration is used due to the lower pressure drop. [146][147][148] Another concept which is ...
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... in a tubular reactor cooled in counter-current (or co-current) flow with the cold feed gas for the first reactor. 149 This has the advantage that only a small feed gas preheater (up to about 130 1C) is required which results in a decreasing temperature along the reaction path maintaining the equilibrium driving force for methanol production (Fig. ...
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... operating temperatures improve the reaction kinetics (at the risk of by-product formation) while low temperatures at the reactor outlet are favoured by the equilibrium, maximising the overall conversion. Detailed temperature profiles of exemplary converters are given in Fig. 7. As seen, the Superconverter design as well as the MegaMethanol process achieve relatively low temperatures at the outlet and only a small preheater is necessary due to the internal preheating of the feed gas. The heat transfer coefficient and the peak catalyst temperature determine the steam pressure of the cooled reactors, which is ...
Citations
... The FT synthesis from carbon monoxide(CO)-and H 2 -rich syngas is a state-of-the-art technology with its first commercial implementation in the 1930s [11,12]. However, the direct conversion of CO 2 into longchain hydrocarbons is not yet feasible with sufficient selectivity and conversion and requires further research for future applications [12,13]. ...
... The FT synthesis from carbon monoxide(CO)-and H 2 -rich syngas is a state-of-the-art technology with its first commercial implementation in the 1930s [11,12]. However, the direct conversion of CO 2 into longchain hydrocarbons is not yet feasible with sufficient selectivity and conversion and requires further research for future applications [12,13]. Thus, a CO 2 reduction to CO is needed to provide appropriate syngas for the subsequent kerosene production. ...
... The process uses a lowtemperature Fischer-Tropsch (LTFT) synthesis, enabling the production of a paraffinic syncrude that is well-suited for kerosene production. A CO and H 2 -rich syngas is required, as CO 2 behaves inertly under most LTFT catalysts [11,12,27]. FT synthesis with direct CO 2 utilization is a promising alternative and the focus of current research. ...
To achieve long-term greenhouse gas (GHG) neutrality within the aviation sector, substituting fossil aviation fuels with Sustainable Aviation Fuels (SAF) derived from renewable energy sources is essential. Among the synthetic SAF options produced through Power-to-Liquid (PtL) processes, the Fischer-Tropsch (FT) and methanol pathway are of significant interest. However, to assess and compare these pathways, detailed technical process analyses are required to provide a sound basis for economic and environmental assessments. Thus, this research paper investigates and compares both SAF production pathways starting from power-derived syngas within an in-depth technical analysis, providing novel insights into overall process characteristics and efficiencies. Carbon and energy flows are derived from steady-state flowsheet simulations. A variation of technical parameters (FT pathway: FT chain growth probability and hydrocracking behavior, Methanol pathway: Dehydration olefin-selectivity and oligomerization product distribution) is carried out to assess impacts on carbon and energy efficiency , indicating uncertainties and parameter ranges for optimized kerosene production. The results show a very high carbon efficiency of the FT pathway (98 to 99%) regarding the total liquid products, while the carbon efficiency regarding kerosene lies between 60 and 77%. For the methanol pathway, a higher kerosene carbon efficiency can be achieved (60 to 90%); however, the total product efficiency (74 to 92%) is notably lower. The energy efficiencies of both pathways behave similarly to carbon efficiency, with the methanol pathway benefiting from thermodynamic advantages, leading to higher energy efficiency at equal carbon efficiency. Within the FT pathway, kerosene efficiency increases at high chain growth probabilities, while a high olefin-selectivity is crucial for efficient kerosene production within the methanol pathway. The analysis results provide comprehensive insights into the technical behavior of the overall processes which contributes to an improved understanding of the production pathways.
... They can be categorized as biofuels (if derived from biomass), renewable fuels (obtained from renewable sources or a mixture that includes biomass), or e-fuels (unrelated to biomass but still renewable). Among the available processes for producing synthetic fuels, the Fischer-Tropsch (FT) process stands out for its versatility in customizing the fuel, its adaptability in combination with other processes, and its historically proven reliability [6][7][8][9][10][11]. ...
Fischer-Tropsch Synthesis (FTS) allows the conversion of syngas to high-density liquid fuels, playing a key role in the petrochemical and global energy sectors over the last century. However, the current Global Challenges impose the need to recycle CO2 and foster green fuels, opening new opportunities to adapt traditional processes like FTS to become a key player in future bioenergy scenarios. This review discusses the implementation of CO2-rich streams and in tandem catalysis to produce sustainable fuels via the next generation of FTS. Departing from a brief revision of the past, present, and future of FTS, we analyse a disruptive approach coupling FTS to upstream and downstream processes to illustrate the advantages of process intensification in the context of biofuel production via FTS. We showcase a smart tandem catalyst design strategy addressing the challenges to gather mechanistic insights in sequential transformations of reagents in complex reaction schemes, the precise control of structure-activity parameters, catalysts aging-deactivation, optimization of reaction parameters, as well as reaction engineering aspects such as catalytic bed arrangements and non-conventional reactor configurations to enhance the overall performance. Our review analysis includes technoeconomic elements on synthetic aviation fuels as a case of study for FTS applications in the biofuel context discussing the challenges in market penetration and potential profitability of synthetic biofuels. This comprehensive overview provides a fresh angle of FTS and its enormous potential when combined with CO2 upgrading and tandem catalysis to become a front-runner technology in the transition towards a low-carbon future.
... Wang et al. (2023a) managed to produce 40% C 12 + olefins via the Kölbel-Engelhardt Frontiers in Energy Research 02 frontiersin.org Overview of the state of the art in Fischer-Tropsch synthesis, including reactor setup comparison, influence of key process parameters on product distribution, used catalysts and supports, and bifunctionality based on slurry/fixed bed/fluidized bed (Guettel et al., 2008;Dieterich et al., 2020); trends of operation parameters (Mena Subiranas et al., 2008;Horáček, 2020); promoters (Chun et al., 2020;Gholami et al., 2021); supports (Keyvanloo et al., 2014;Munirathinam et al., 2018); and bifunctional operation (Martínez-Vargas et al., 2019). ...
Fischer–Tropsch (FT) synthesis is an important module for the production of clean and sustainable fuels and chemicals, making it a topic of considerable interest in energy research. This mini-review covers the current literature on FT catalysis and offers insights into the primary products, the nuances of the FT reaction, and the product distribution, with particular attention to the Anderson–Schulz–Flory distribution (ASFD) and known deviations from this fundamental concept. Conventional FT catalysts, particularly Fe- and Co-based catalysis systems, are reviewed, highlighting their central role and the influence of water and water–gas shift (WGS) activity on their catalytic behavior. Various mechanisms of catalyst deactivation are also investigated, and the high methanation activity of Co-based catalysts is illustrated. To make this complex field accessible to a broader audience, we explain conjectured reaction mechanisms, namely, the carbide mechanism and CO insertion. We discuss the complex formation of a wide range of products, including olefins, kerosenes, branched hydrocarbons, and by-products such as alcohols and oxygenates. The article goes beyond the traditional scope of FT catalysis by addressing topics of current interest, including the direct hydrogenation of CO2 for power-to-X applications and the use of bifunctional catalysts to produce tailored FT products, most notably for the production of sustainable aviation fuel (SAF). This mini-review provides a holistic overview of the evolving landscape of FT catalysts and is aimed at both experienced researchers and those new to the field while covering current and emerging trends in this important area of energy research.
... However, cars with combustion engines may still be registered after 2035, if they are fueled exclusively by CO 2 -neutral e-fuels [6]. Thus, coupling the energy and transport sectors in a power-to-liquid (PtL) approach [7][8][9][10][11][12][13][14][15][16] will continue to be pursued as a bridging technology. In addition, heavy-duty trucks, lorries and buses, as well as global shipping and aviation, cannot be transformed to all-electric propulsion systems within this timeframe. ...
... In recent years, many Techno-economic Assessment (TEA) and some Life Cycle Assessment (LCA) studies have been published in the field of CO 2 -based fuels such as methanol (MeOH), dimethyl ether (DME), oxymethylene dimethyl ethers (OME [3][4][5], and Fischer-Tropsch-fuels (FT fuels) [16]. Especially MeOH and DME have been in the focus of numerous studies [7,12,13,17,[19][20][21][22][23][24][25][26][27][28][29][30][31][32]. While CO 2 -based MeOH production is already demonstrated at bench-and pilot-scale plants with a TRL of 8 [26], currently, CO 2 -based DME production has a TRL of about 4-5, but progress is being made to further increase its technological maturity [33]. ...
... MeOH is the first synthesis step within the investigated production pathway. There are a plenty of detailed studies for various production pathways for synthetic MeOH [7,55,[58][59][60][61][62]. For this analysis, the used model for CO 2 -based MeOH synthesis was developed by Schemme [55] on the basis of the work by Otto [62]. ...
... Green hydrogen can be used as a fuel per se or as a feedstock to produce chemicals or other fuel types, such as ammonia, methanol, and dimethyl ether. The resulting fuels are referred to as "efuels", and the whole process is frequently labeled Power-to-X [2,3]. E-fuels are currently several times more expensive than fuels produced from fossil sources. ...
... Both methanol formation pathways are usually carried out over CuO/ZnO/ Al 2 O 3 catalysts and are connected via the reverse water gas shift (RWGS) reaction. However, the production of methanol via the CO 2 route is characterized by low yields, single-pass reactor conversions and the formation of by-product water [36,37]. Typically, unreacted educts are recycled back to the reactor inlet to improve the overall conversion rates of H 2 and CO 2 . ...
... Available studies on P2M systems and all related techno-economic assessments (TEA) are almost exclusively focussed on conventional O-SOECs [36,42,[45][46][47][48]. Except for [33], no stationary or transient modeling and simulation studies on the application of H-SOECs within P2M system frameworks have been reported. ...
... and the reverse water gas shift reaction (RWGS) reading Since the theoretical equilibrium-limited methanol yields as well as the reactant conversion rates of the MeOH formation (Eq. 17) are relatively low (18 to 58% at 200 to 250 • C and 50 to 100 bar), unreacted H 2 / CO 2 is typically recycled back into the reactor feed to counteract the resulting low single-pass conversion rates [36]. Relevant recycle ratios (ξ rec ; see Eqs. 1 and 22) range from 2 to 5 [7,64,65]. ...
Methanol is a crucial commodity in the chemical industry and is employed as precursor for many products. It can be used to store fluctuating renewable energy, specifically benefiting from its liquid state at ambient temperatures. As the demand for green, renewable methanol is projected to soar in the next decades, environmentally friendly and sustainable pathways for its production have to be provided. Through the combination of proton-conducting high temperature electrolysis for the provision of dry H2 with a heterogeneously catalyzed hydrogenation of CO2, efficient and simple power-to-methanol production processes can be established. Here, a novel power-to-methanol system model capable of real-time transient simulation is presented and viable operating windows are determined for different key operating parameters of the respective main process stages. A techno-economic assessment is carried out to determine the specific production costs of renewable methanol. Specific methanol production costs of 2419 €/tMeOH for small-scale applications (1.12 MW) were retrieved, which corresponds to a more than fourfold increase over the current market price of conventionally produced methanol. Increases in system scale are found to decrease the methanol production costs due to economy-of-scale effects. The sensitivity of the process economics is assessed with regards to crucial operational and capital characteristics.
... Given the challenges associated with substantial storage and long-distance transportation of H 2 , its conversion into a liquid fuel is a viable option [8,9]. Solar methanol (MeOH) is a promising contender for liquid fuels [10][11][12][13][14][15], as it can offer a cost-competitive alternative to fossil fuels for electricity, transport and vehicles, as well as fossil-based feedstocks for chemicals industries. Many studied on renewable methanol systems were investigated. ...
... Instead of this most widely realized utilization pathway, biogaswhich typically consists mainly of methane (CH 4 ) and carbon dioxide (CO 2 ) -can also be converted into higher-value substances through reforming and subsequent synthesis processes. Due to its selective and small-scale implementable synthesis technology, methanol (CH 3 OH) is particularly suitable as a target product [4,5]. Methanol is one of the most important organic primary chemicals, with a global (fossil-based) production exceeding 100 Mt/a [6,7]. ...
... The nominal capacity of the production facility typically does not affect the carbon and energy efficiency. 5 Still, it does influence the specific plant costs (economy-of-scale) and, consequently, the methanol production costs (MPCs). In the reference case, the plant size is designed for an available biogas quantity of 670 Nm 3 /h, corresponding to a medium-to large-scale biogas plant. ...
... 7,500 h/a (full load) are assumed (plant utilization of 85 %), constrained by the typical annual full load hours of biogas 4 Since the activated carbon filter has no relevant influence on the mass and energy flows of the overall process, it is not included in the modeling. 5 Assuming the process concept, including process integration, remains unchanged, and the equipment is adapted to the respective performance classes. In very small-scale plants, the influence of heat losses can lead to reduced efficiencies. ...
... Methanol produced from captured CO 2 can serve as a precursor to fuel production through gas-to-liquid (GTL) processes, which have the potential to significantly reduce the need to recover virgin fuel while providing a low-carbon pathway for meeting the energy demand for transportation [5]. Notwithstanding the fact that many of the processes considered in this study, such as the catalytic production of methanol from captured carbon dioxide and green hydrogen, are still in the early phases of development, transition scenarios can be posited wherein the techno-economic maturity of the proposed processes ...
The production of hydrogen-based dense energy carriers (DECs) has been proposed as a combined solution for the storage and dispatch of power generated through intermittent renewables. Frameworks that model and optimize the production, storage, and dispatch of generated energy are important for data-driven decision making in the energy systems space. The proposed multiperiod framework considers the evolution of technology costs under different levels of promotion through research and targeted policies, using the year 2021 as a baseline. Furthermore, carbon credits are included as proposed by the 45Q tax amendment for the capture, sequestration, and utilization of carbon. The implementation of the mixed-integer linear programming (MILP) framework is illustrated through computational case studies to meet set hydrogen demands. The trade-offs between different technology pathways and contributions to system expenditure are elucidated, and promising configurations and technology niches are identified. It is found that while carbon credits can subsidize carbon capture, utilization, and sequestration (CCUS) pathways, substantial reductions in the cost of novel processes are needed to compete with extant technology pathways. Further, research and policy push can reduce the levelized cost of hydrogen (LCOH) by upwards of 2 USD/kg.
... Liquid hydrocarbons are then further upgraded or converted into specific products, such as diesel, gasoline, dimethyl ether (DME), and kerosene. Two main pathways for producing liquid hydrocarbons are FT synthesis and the methanol route [80,81]. Methanol can also be used directly as a substitute for gasoline [42]. ...
... Methanol is converted and upgraded into liquid fuels via direct DME synthesis, olefin synthesis, oligomerisation, and hydrotreatment. The FT route has been investigated more extensively for commercialisation than the DME route [81,82]. ...
Owing to the ongoing energy crisis, increasing shares of renewables, and climate mitigation targets, a green hydrogen economy through water electrolysis has gained interest. Hydrogen can be directly utilised or converted via different Power-to-X pathways to produce fossil-free substitutable products; therefore, their life-cycle emissions were studied to determine whether these solutions could provide sustainable alternatives. Thus, understanding which Power-to-X solution can provide the greatest greenhouse gas emission reduction is crucial. This study provides nine meta-analyses of different pathways to compare climate emissions reductions based on the literature. The minimum, maximum, and average values were estimated for each investigated Power-to-X pathway. The direct use of hydrogen or its service to produce steel, biogas upgrading, protein, or ammonia resulted in over 10 kgCO2 kgH2−1 reductions on average while using low-carbon energy sources. Co-electrolysis can potentially provide higher emission savings owing to lower electricity consumption compared with low-temperature electrolysers. In addition, the possibility of integrating electrochemical synthesis with hydrogen production has great potential, but the usability depends on the advancement of the technology in the future. Selections of carbon dioxide sources, substitutable products, and other assumptions of the investigated studies significantly impact the reduction potential. Low-emission-factor electric grid mixes containing fossil sources can result in emission savings in many Power-to-X systems. However, using grid mixes that result in emission savings is system-dependent, and the largest emission savings are achieved through renewables or nuclear energy.
