Low Temperature Fischer Tropsch Research Articles

An Overview of Low-Temperature Fischer–Tropsch Synthesis: Market Conditions, Raw Materials, Reactors, Scale-Up, Process Intensification, Mechanisms, and Outlook

An Overview of Low-Temperature Fischer–Tropsch Synthesis: Market Conditions, Raw Materials, Reactors, Scale-Up, Process Intensification, Mechanisms, and Outlook

Effect of a High Thermal Capacitance Core–Shell Structure on Co-Ru/SiO2 Catalyst for Low Temperature Fischer–Tropsch Synthesis

Effect of a High Thermal Capacitance Core–Shell Structure on Co-Ru/SiO2 Catalyst for Low Temperature Fischer–Tropsch Synthesis

Catalytic Performance of Alumina-Supported Cobalt Carbide Catalysts for Low-Temperature Fischer–Tropsch Synthesis

The determination of the catalyst’s active phase helps improve the catalytic performance of the Fischer–Tropsch (FT) synthesis. Different phases of cobalt, including cobalt oxide, carbide, and metal, exist during the reaction. The content of each phase can affect the catalytic performance and product distribution. In this study, a series of cobalt carbide catalysts were synthesized by exposure of Co/Al2O3 catalyst to CH4 at different temperatures from 300 °C to 800 °C. The physicochemical properties of the carbide catalysts (CoCx/Al2O3) were evaluated by different characterization methods. The catalytic performances of the catalysts were investigated in an autoclave reactor to determine the role of cobalt carbides on the CO conversion and product distribution during the reaction. XRD and XPS analysis confirmed the presence of Co2C in the prepared catalysts. The higher carbidation temperature resulted in the decomposition of methane into hydrogen and carbon, and the presence of graphitic carbon was confirmed by XRD, XPS, SEM, and Raman analysis. The Co2C also decomposed to metallic cobalt and carbon, and the content of cobalt carbide decreased at higher carbidation temperatures. Higher content of Co2C resulted in a lower CO conversion and higher selectivity to light alkanes, mainly methane. The higher carbidation temperature resulted in the decomposition of Co2C to metallic cobalt with higher activity in the FT reaction. The CO conversion increased by increasing the carbidation temperature from 300 °C to 800 °C, due to the higher content of metallic cobalt. In the presence of pure hydrogen, the Co2C could be converted mainly into hexagonal, close-packed (hcp) Co with higher activity for dissociative adsorption of CO, which resulted in higher catalyst activity and selectivity to heavier hydrocarbons.

The Use of Iron Ore as a Catalyst in Fischer–Tropsch Synthesis—A Review

The use of iron ore as an alternative to conventional Fischer–Tropsch synthesis (FTS) iron catalyst has been identified as a way to achieve a cost-effective catalyst. In recent times, considerable progress has been made to build a strong case for iron ore as a viable alternative to traditional iron catalysts. Nevertheless, there are still opportunities to enhance the current iron ore low-temperature Fischer–Tropsch (LTFT) catalysts and pave the way for optimal performing catalysts. In this study, we thoroughly examined the various publications on iron ore catalysts used for FTS and highlighted the research gaps in the studies. The study identified the progress made so far, opportunities, and challenges regarding the use of iron ore as a catalyst in FTS. One of the critical areas that needs to be addressed from the review is establishing the deactivation pathways of these catalyst systems. The application of advanced spectroscopic and computational methods is also suggested to elucidate the relationship between the synthesis conditions, active catalytic sites, reaction intermediates, and catalytic performance to fabricate optimized iron ore LTFT catalysts.

Inlet hydrogenation gas chromatography to predict mass % linear paraffin content

The light condensate fraction obtained from the low temperature Fischer-Tropsch (LT-FT) process is very complex and it is processed further by hydrotreating to produce hydrocarbon products that can be sold as final products. The mass% linear paraffins in some of the final paraffin products is listed as a required specification. Usually gas chromatography equipped with a flame ionisation detector (GC-FID) is used for the analysis of the condensate feeds to estimate the mass% linear paraffins that can be expected in the final products after commercial hydrogenation. This is an important parameter used in the blending of suitable condensate feeds. Due to the complexity of the condensate feeds, significant peak overlap occurs in the GC-FID analysis, making it difficult to accurately estimate the mass% linear paraffin content that will be obtained in the hydrogenated products. Inlet hydrogenation GC-FID analysis simplifies the prediction of the mass% linear content that can be expected in the paraffin product fractions from the analysis of a plant feed since the feed is hydrogenated in the GC inlet before GC-FID analysis. The results from this study showed that sufficient hydrogenation without significant peak tailing can be obtained in the GC inlet when using the appropriate mass and particle size Pd/Al2O3 catalyst with the optimum bed height. Inlet hydrogenation GC-FID analysis simplifies the prediction of the mass% linear content that can be expected in the paraffin product fractions. The method can be implemented on routine GC-FID instrumentation by simply installing an inlet liner containing an appropriate catalyst, that could be re-used at least 20 times, and avoids the purchasing of additional instrumentation and complex data processing and is suitable for commercial process control.

Robust simulation-optimization framework for synthesis and design of natural gas downstream Incorporating renewable hydrogen network under uncertainty

Many intrinsic uncertainties are part of natural gas downstream synthesis, design, and operation. This work extends the earlier developed deterministic model to account for new decision variables, unit operations, and uncertainty in the network. The uncertainty includes the feedstock composition and flowrate, utility requirements, by-products, and final product market price. The proposed two-stage stochastic model includes new major processing units (helium recovery units), hydrogen production via renewable technologies (biomass gasification, water electrolysis), and operating modes. The stochastic formulation simultaneously considers uncertainty in 12 different model parameters. The model's first stage aims to find the optimal network's design variables, such as processing units, technologies, and operating modes common to all scenarios. The second stage is concerned with deriving operational variables, for example, the network's overall inlet feedstock flowrates, individual units' inlet flowrates, and units' capacity. Outcomes obtained for a range of uncertain material/energy feedstock and products/by-products market prices result in higher expected operating profits than the equivalent deterministic model. The analysis's key takeaways show that the most prevailing network consists of two syngas technologies: (1) auto-thermal reforming to feed a low-temperature Fischer Tropsch synthesis unit and (2) steam methane reforming for hydrogen production. Additionally, renewable hydrogen is produced via electrolysis and biomass gasification. There is an improvement of 2.22% in the objective function value using the stochastic approach instead of the deterministic.

The Potential Use of Raw Iron Ore in Fischer-Tropsch Synthesis

Fischer-Tropsch (FT) synthesis has been studied in the literature as a greener pathway to cleaner and sustainable hydrocarbons production. However, the cost to upscale laboratory FT formulations to pilot scale is significantly expensive. This work proposes a cheaper and scalable low-temperature FT modified iron ore catalyst that is mechanically suited for fixed bed reactors. The mechanical strength reported in this investigation was three times more than commercial alumina spherical pellets and, therefore, suitable for pilot scale scenarios. A manufacturing cost analysis of iron ore was estimated to be US$38.45/kg using the CatCost model, and the conventionally prepared iron catalyst was US$71.44/kg using the same model. The manufacturing cost estimations of modified iron ore were found to be 46% cheaper than a conventional commercial iron catalyst. The catalytic performance of the modified iron ore catalyst showed a CO conversion of 72.1% ±4.24, with WGS and C5+ selectivity 48.6% ±1.96 and 83.2% ± 5.24, respectively. These findings were comparable (both in CO conversion and product selectivity) to the ones reported by other researchers.

Fischer–Tropsch Synthesis in the Presence of Catalysts Based on Unmodified Iron Ores

The use of commercial magnetite-type iron ore and of ferriferous quartzite type ore as catalysts for low-temperature Fischer–Tropsch synthesis is described. According to the results of chemical analysis, the ores mainly contained iron magnetite, carbon, and also baddeleyite (ZrO2 + HfO2) and hatchettolite (Ta2O5 + Nb2O5 + U3O8). The ore samples with the highest iron content (48–59%) and the lowest sulfur content (0.1% and less) showed activity in the Fischer–Tropsch synthesis without additional modification in the commercial form. The yield of liquid products in the synthesis performed on the most active samples of ore catalysts exceeded 100 g m–3 at the СО conversion of approximately 60%. The ore activity in the Fischer–Tropsch synthesis may be associated with the fact that these natural mineral formations contain oxides exerting a promoting effect when using the ores as catalysts.

Accumulation and distribution of higher hydrocarbons in the pores of a cobalt catalyst during low-temperature Fischer–Tropsch fixed-bed synthesis

Simplified model approach based on the vapor liquid equilibrium to describe hydrocarbon distribution along the fixed-bed or with CO conversion. Experimental validation in a single pellet string reactor.

Experimental Determination of H2 and CO Diffusion Coefficients in a Wax Mixture Confined in a Porous Titania Catalyst Support.

The ability to measure and predict molecular diffusion coefficients in multicomponent mixtures is not only of fundamental scientific interest but also of significant relevance in understanding how catalytic processes proceed. In the present work, the direct measurement of the molecular diffusion of H2 and CO gas-phase species diffusing in n-alkane mixtures using pulsed-field gradient (PFG) nuclear magnetic resonance (NMR) methods is reported. The work is of direct relevance to Fischer-Tropsch (FT) catalysis, with the measurements being made of the gas-wax system with the wax in both the bulk liquid state and when confined within a titania catalyst support, at temperatures and pressures typical of low-temperature FT synthesis. Molecular diffusion coefficients of H2 and CO within wax-saturated porous titania in the range (1.00-2.43) × 10-8 and (6.44-8.50) × 10-9 m2 s-1, respectively, were measured in the temperature range of 140-240 and 200-240 °C for H2 and CO, respectively, at a pressure of 40 bar. The wax mixture was typical of a wax produced during FT catalysis and had a molar average carbon number of 36. It is shown that the hydrogen diffusion coefficient within this wax mixture is consistent, to within experimental error, with the hydrogen diffusion coefficient measured in pure single-component n-hexatriacontane (n-C36) wax; this result held with the waxes in the bulk liquid state and when confined within the porous titania. The tortuosity of the porous titania was also measured using PFG NMR and found to be 1.77; this value is independent of temperature. The ability of existing correlations to predict these experimentally determined data was then critically evaluated. Although the Wilke-Chang correlation was found to underestimate the molecular diffusion coefficients of both H2 and CO diffusing in the wax in both the bulk state and when confined within the porous titania, parameterized correlations based on the rough hard sphere model, having accounted for the experimentally determined tortuosity factor, predicted the H2 and CO diffusion within bulk and confined wax to within 3%.

Diffusion-dependent upgrading of hydrocarbons synthesized by Co/zeolite bifunctional Fischer–Tropsch catalysts

The design of efficient zeolite-supported Co catalysts is essential for the further development of the one-step production of liquid fuels via the low-temperature Fischer–Tropsch synthesis (FTS). Herein, Co/zeolite catalysts were prepared from zeolites SSZ-13, ZSM-22, ZSM-11, ZSM-5, Mordenite, and Y. Their textural and acidic properties, Co dispersion, and internal diffusion behaviors were comprehensively analyzed, along with their FTS product mixtures. Counterintuitively, the degree of isomerization and hydrocarbon decomposition did not correlate with the acidic properties of the zeolite support. Instead, catalysts with high characteristic diffusivity delivered product mixtures with high degree of isomerization and decomposition, suggesting that the access of paraffinic hydrocarbons to the internal acid sites of the zeolite determines the upgrading performance of the bifunctional Co/zeolite catalyst in the low-temperature FTS reaction. Hence, the present findings support upcoming efforts on the design of new and effective FTS catalysts.

Brief Review of Precipitated Iron-Based Catalysts for Low-Temperature Fischer–Tropsch Synthesis

Fischer–Tropsch synthesis (FTS) is a promising way to produce clean liquid fuels and high value-added chemicals from low-value carbon-containing resources such as coal, natural/shale gas, waste wood/plastics, and CO2 via syngas (CO + H2). Precipitated iron-based catalysts are one group of commercially viable FTS catalysts that are important in academic circles as well as in industry. Here, we briefly review the promoters for precipitated iron-based FTS catalysts, which critically influence the catalyst performance. Precipitated iron-based catalysts typically contain three types of promoters: reduction promoters, alkali promoters, and structural promoters. The major effects of reduction promoters on catalytic performance include shortening of the induction period and increasing the CO conversion. Alkali promoters significantly influence the catalyst activation and product selectivity. They facilitate carburization of iron and increase selectivity for the target hydrocarbons C5+ and 1-olefin. The heavier the alkali metal, the stronger the effect. The structural promoters are effective for increasing the resistance of precipitated iron-based catalysts to thermal sintering and physical attrition. However, the impact of structural promoters on chemical properties and resultant catalytic performance is still considered a matter of debate. In the case of alkali promoters and structural promoters, the optimal amount of loading is very important for obtaining high catalytic performance, and this deteriorates severely if loading exceeds the optimal range.

Maximizing paraffin to olefin ratio employing simulated nitrogen-rich syngas via Fischer-Tropsch process over Co3O4/SiO2 catalysts

The optimization of cobalt oxide (Co3O4) loading on silica for the low-temperature Fischer-Tropsch (LTFT) synthesis process employing simulated nitrogen-rich syngas (50 vol%) to produce highly paraffinic biodiesel is studied. Four different amounts of Co3O4 varying from 15 to 36 wt% were loaded on silica in order to examine the catalytic performance of Co/SiO2 catalysts. The supported catalysts were characterized using XRF, nitrogen physisorption, XRD, TPR, DRIFT and SEM fixed with EDS analysis. The performances of the catalysts were examined in a single channel fixed bed reactor employing simulated nitrogen-rich syngas (CO:H2:N2 = 17:33:50 vol%). The reactor was operated at P = 20 bar, T = 237 °C and WHSV = 3.0 Nl/h.gcat. The active site concentration was maximized by (i) utilizing all the available surface area of the sphere's porous support, (ii) using ethanolic impregnation solution to hinder sintering of Co3O4 phases due to presence of ethoxyl groups, and (iii) connecting oxide crystallites to the neighbouring pores by increasing the active metal content. As a result, the production of heavy hydrocarbons per unit of time was maximized with 36 wt% cobalt loading on silica (CO conversion and C5+ selectivity were 87.65 and 81.78 mol%, respectively, and also paraffin: olefin ratio was 98:2).

Production of biofuel by low temperature Fischer-Tropsch using Co-K/γ-Al2O3

Fischer Tropsch is a heterogeneous catalytic chemical reaction which converts a mixture of hydrogen and carbon monoxide (syngas) into a hydrocarbon product with varying chain length by polymerization reaction on the surface of the catalyst. The hydrocarbon produced from Fischer Tropsch reaction using bio-syngas is biofuel (diesel, kerosene, gasoline) that can replace petroleum-based fuels. Cobalt catalyst with potassium promoter and γ-Al2O3 support has been successfully synthesized in Catalysis and Reaction Engineering (CaRE) laboratory, Institut Teknologi Bandung (ITB). Co-K/γ-Al2O3 catalyst was prepared by dry impregnation method on the γ-Al2O3 support under alkaline conditions. Catalysts were characterized using X-Ray Diffraction (XRD), temperature program reduction (TPR), and N2 physisorption measurements such as Barrett-Joyner-Halenda (BJH) and Brunauer-Emmett-Teller (BET) methods. Co-K/γ-Al2O3 catalyst activity was evaluated using fixed bed reactor with various flow rates and temperatures which is still classified as Low-Temperature Fischer Tropsch (LTFT) process. The best results were obtained at minimum syngas flow rate and highest reaction temperature with a total pressure of 20 bar. The results show CO and H2 conversions were 96.6% and 82.31% respectively. Selectivity value of the hydrocarbon product was calculated using the Anderson Shultz Flurry (ASF) equation. The greatest selectivity value was obtained for C5+ product with selectivity value was 86.07 % wt.

Core–Shell Metal Zeolite Composite Catalysts for In Situ Processing of Fischer–Tropsch Hydrocarbons to Gasoline Type Fuels

Fischer–Tropsch synthesis has two main challenges related to direct production of gasoline fuels. First, the chain length distribution of the products follows a broad and unselective Anderson–Schulz–Flory distribution. Second, mostly linear hydrocarbons are formed in the Fischer–Tropsch reaction, thus requiring isomerization while manufacturing gasoline fuels. The present paper addresses a synthetic strategy for the preparation of hierarchical metal and zeolite nanocomposite catalysts for direct synthesis of iso-paraffins from syngas. The nanocomposites are synthesized in three steps. In the first step, the parent (core) zeolite is etched with an ammonium fluoride solution. The etching creates small mesopores inside the zeolite crystals. In the second step, the Ru nanoparticles prepared using water-in-oil microemulsion are deposited in the mesopores of the zeolite. In the third step, a zeolite shell of MFI-type zeolites (silicalite-1 or ZSM-5) is grown on the parent zeolite crystals coating both the etched surface and metallic nanoparticles. Thus, the metal nanoparticles become entirely encapsulated inside the zeolite matrix. Most important parameters such as ruthenium content, zeolite mesoporosity, and more particularly, the acidity of the catalyst shell, which affect the catalytic performance of the synthesized nanocomposite materials in low-temperature Fischer–Tropsch synthesis were identified in this work. The higher relative amount of iso-paraffins was observed on the catalysts containing a shell of ZSM-5. The proximity between metal and acid sites in the zeolite shell of the nanocomposite catalysts is a crucial parameter for the design of efficient metal zeolite bifunctional catalysts for selective synthesis of gasoline-type fuels via Fischer–Tropsch synthesis, while the acidity of the catalyst core has only a limited impact on the catalytic performance.

Price Risk For Coal Liquefaction in Moderate Scale Development

According to Talla et al,2017 the Linde Hampson Method can be used to process solid changes into liquid. In this study aims to calculate the Linde Hampson method in the temperature range of the Fischer Tropsch method (LTFT /Low temperature fischer tropsch). The temperatures used for comparison include low temperatures of 200 to 250degC. Parameters compared from the four type of coal namely lignite, antrachitre, bituminous and subbituminous are tested with projects on a moderate scale of 100 – 1000 tons.
 Analysis of Price risk is carried out to see the trend of change (increase/decrease) in the price of selling syngas. Price can change because of supply and demand. The main factor that can change price is quantity and quality of heat (HHV) and composition. Development of subbituminous can have higher risk than the antrachite type. Based on the calculation of the standard deviation of the risk values obtained from the four types is 25,3$.

Kinetics of Fischer–Tropsch Synthesis in a 3-D Printed Stainless Steel Microreactor Using Different Mesoporous Silica Supported Co-Ru Catalysts

Fischer–Tropsch (FT) synthesis was carried out in a 3D printed stainless steel (SS) microchannel microreactor using bimetallic Co-Ru catalysts on three different mesoporous silica supports. CoRu-MCM-41, CoRu-SBA-15, and CoRu-KIT-6 were synthesized using a one-pot hydrothermal method and characterized by Brunner–Emmett–Teller (BET), temperature programmed reduction (TPR), SEM-EDX, TEM, and X-ray photoelectron spectroscopy (XPS) techniques. The mesoporous catalysts show the long-range ordered structure as supported by BET and low-angle XRD studies. The TPR profiles of metal oxides with H2 varied significantly depending on the support. These catalysts were coated inside the microchannels using polyvinyl alcohol and kinetic performance was evaluated at three different temperatures, in the low-temperature FT regime (210–270 °C), at different Weight Hourly Space Velocity (WHSV) in the range of 3.15–25.2 kgcat.h/kmol using a syngas ratio of H2/CO = 2. The mesoporous supports have a significant effect on the FT kinetics and stability of the catalyst. The kinetic models (FT-3, FT-6), based on the Langmuir–Hinshelwood mechanism, were found to be statistically and physically relevant for FT synthesis using CoRu-MCM-41 and CoRu-KIT-6. The kinetic model equation (FT-2), derived using Eley–Rideal mechanism, is found to be relevant for CoRu-SBA-15 in the SS microchannel microreactor. CoRu-KIT-6 was found to be 2.5 times more active than Co-Ru-MCM-41 and slightly more active than CoRu-SBA-15, based on activation energy calculations. CoRu-KIT-6 was ~3 and ~1.5 times more stable than CoRu-SBA-15 and CoRu-MCM-41, respectively, based on CO conversion in the deactivation studies.

Cobalt-nickel bimetallic Fischer-Tropsch catalysts: A combined theoretical and experimental approach

Abstract The low temperature Fischer-Tropsch (FT) synthesis reaction is commercially performed on either Fe- or Co-based systems, while Ni-based systems are not considered due to a poor selectivity profile. This study focuses on alternative bimetallic catalytic materials for FT in which both Co and Ni are present. Co-Ni based alloys have been identified as a possible FT synthesis catalyst through a separate, DFT based computational chemistry screening approach of various bimetallic alloys based on the similarity of their underlying calculated electronic structures to that of Co. Based on this screening result and a cost filtering, several supported catalysts have been prepared with varying Co:Ni ratios. These catalysts have been characterised with various techniques (TPR, EDS, EELS, Magnetic measurements) to assess whether these catalysts indeed show Co-Ni alloy formation. These materials were also tested for FT synthesis activity, showing that the selectivities of the Co-Ni alloys are similar to that of pure Co up to a nickel content of 25%. It was also concluded that the computational screening approach can be used to execute predictive metal screening.

CO as a Promoting Spectator Species of CxHy Conversions Relevant for Fischer–Tropsch Chain Growth on Cobalt: Evidence from Temperature-Programmed Reaction and Reflection Absorption Infrared Spectroscopy

Cobalt-catalyzed low temperature Fischer–Tropsch synthesis is a prime example of an industrially relevant reaction in which CxHy intermediates involved in chain growth react in the presence of a large quantity of COad. In this study, we use a Co(0001) single-crystal model catalyst to investigate how CO, adsorbed alongside CxHy adsorbates affects their reactivity. Temperature-programmed reaction spectroscopy was used to determine the hydrogen content of the CxHy intermediates formed at different temperatures, and infrared absorption spectroscopy was used to obtain more specific information on the chemical identity of the various reaction intermediates formed. Ethene, propene, and but-1-ene precursors decompose below 200 K. The 1-alkyne adsorbate is identified as a major product, and some alkylidyne species form as well when the initial alkene coverage is high. The surface hydrogen atoms produced in the low temperature decomposition step start leaving the surface >300 K. When an alkyne/Had-covered surface i...

Optimization for biogas to chemicals via tri-reforming. Analysis of Fischer-Tropsch fuels from biogas

This paper presents an optimization approach for the production of syngas from biogas via tri-reforming. The optimization, formulated as a NLP problem, is performed for three syngas ratios according to the desired product: methanol, ethanol or Fischer-Tropsch (FT) fuels. As a result, the optimal operating conditions and biogas composition are defined. For the production of ethanol, a biogas composed by a CH4:CO2 ratio of 0.52:0.48 is desired, requiring 0.035 mol of O2 per mol of Biogas in the reformer. For the production of methanol and FT, biogas with the largest content of methane is suggested to be reformed with 0.275 molO2/mol biogas. The largest H2:CO ratio required for methanol is achieved by feeding steam in a WGS reactor after the reformer. The syngas optimization study is completed by evaluating tri-reforming for the production of FT fuels from biogas via high and low temperature FT synthesis. The production cost for a plant fed with 12 MMm3/y of biogas results in $3/gal for biodiesel via HTFT and $1.7/gal via LTFT.