Fischer-Tropsch Liquids Research Articles

Optimal Process Design for Coproduction of Methanol and Fischer–Tropsch Liquid Fuels

Optimal Process Design for Coproduction of Methanol and Fischer–Tropsch Liquid Fuels

The value of low- and negative-carbon fuels in the transition to net-zero emission economies: Lifecycle greenhouse gas emissions and cost assessments across multiple fuel types

In recent macro-energy systems modeling studies of net-zero emissions pathways for the United States and elsewhere, fuels made via gasification of sustainably produced biomass coupled with carbon capture and storage (CCS) play critical roles in achieving economy-wide net-zero greenhouse gas emissions because they provide carbon-negative energy carriers. In this study, we develop lifecycle greenhouse gas (GHG) emissions and cost assessments to provide insights into the environmental and economic cost and value of hydrogen (H2), synthetic natural gas (SNG), and Fischer-Tropsch liquid (FTL) fuels made from 1) biomass, coupled with CCS, 2) natural gas, with CCS, and 3) renewably-generated electricity. We find that H2 production pathways are less costly to decarbonize than FTL and SNG pathways that use the same input feedstock and also provide the largest reductions in lifecycle GHG emissions per unit of delivered fuel. Sensitivity analyses on the levelized costs of carbon mitigation (LCCM) indicate that capital costs and capacity factors are influential for most of the pathways. Costs for processes that use natural gas as feedstock are more sensitive to changes in input feedstock intensity than other processes. Finally, we find that fuel production pathways starting from biomass and including CCS have the highest carbon mitigation potentials among all feedstock pathways. They also have the lowest production costs beyond certain threshold carbon emission price levels. Our findings help explain the critical role that biomass-based hydrogen production with CCS plays in macro-energy system models of the U.S. transition to net-zero emissions.

Dynamic process simulations and control of a lignite/waste to Fischer Tropsch liquids plant

This study comprises the dynamic process simulations of a HTW gasification plant for Fischer-Tropsch (FT) liquids production under transient feedstock of lignite and solid recovered fuel (SRF) as well as load variations. Main objective of the current study is the proof of concept in unsteady conditions and the effective plant wide control of a novel gasification-driven liquid fuels production pathway. Therefore, the dynamic analysis of all sub-units in an integrated simulation scheme by means of Aspen Plus Dynamics (APD) and MATLAB/Simulink interference is attempted. In this way, it is possible to evaluate the impact of system disturbances on every process stage and apply the required control strategies to ensure system stability. Another aspect addressed within this work is the alternative management of solid materials in APD environment, which is an inherent drawback of this otherwise appropriate software as mentioned in previous studies. The performed dynamic simulations revealed that the proposed value chain seems to have a respectable potential in terms of operational flexibility and performance stability, always in relation to the gasification-based chemical plants and the constraints that accompany them.

Dynamic process simulations and control of a lignite/waste to Fischer Tropsch liquids plant

Dynamic process simulations and control of a lignite/waste to Fischer Tropsch liquids plant

Carbon negative transportation fuels – A techno-economic-environmental analysis of biomass pathways for transportation

Global warming and fossil fuel depletion have necessitated alternative sources of energy. Biomass is a promising fuel source because it is renewable and can be carbon negative, even without carbon capture and storage. This study considers biomass as a clean, renewable source for transportation fuels. An Aspen Plus process simulation model was built of a biomass gasification biorefinery with Fischer-Tropsch (FT) synthesis of liquid fuels. A GaBi life cycle assessment model was also built to determine the environmental impacts using a cradle-to-grave approach. Three different product pathways were considered: Fischer-Tropsch synthetic diesel, hydrogen, and electricity. An offgas autothermal reformer with a recycle loop was used to increase FT product yield. Different configurations and combinations of biorefinery products are considered. The thermal efficiency and cost of production of the FT liquid fuels are analyzed using the Aspen Plus process model. The greenhouse gas emissions, profitability, and mileage per kg biomass were compared. The mileage traveled per kilogram biomass was calculated using modern (2019–2021) diesel, electric, and hydrogen fuel cell vehicles. The overall thermal efficiency was found to be between 20 and 41% for FT fuels production, between 58 and 61% for hydrogen production, and around 25–26% for electricity production for this biorefinery. The lowest production costs were found to be $3.171/gal of FT diesel ($24.304/GJ), $1.860/kg of H 2 ($15.779/GJ), and 13.332¢/kWh for electricity ($37.034/GJ). All configurations except one had net negative carbon emissions over the life cycle of the biomass. This is because carbon is absorbed in the trees initially, and some of the carbon is sequestered in ash and unconverted char from the gasification process, furthermore co-producing electricity while making transportation fuel offsets even more carbon emissions. Compared to current market rates for diesel, hydrogen, and electricity, the most profitable biorefinery product is shown to be hydrogen while also having net negative carbon emissions. FT diesel can also be profitable, but with a slimmer profit margin (not considering government credits) and still having net negative carbon emissions. However, our biorefinery could not compete with current commercial electricity prices in the US. As oil, hydrogen, and electricity prices continue to change, the economics of the biorefinery and the choice product will change as well. For our current biorefinery model, hydrogen seems to be the most promising product choice for profit while staying carbon negative, while FT diesel is the best choice for sequestering the most carbon and still being profitable.

Comparison of BGL and Lurgi gasification for coal to liquid fuels (CTL): Process modeling, simulation and thermodynamic analysis

Fixed bed gasifiers are widely used for the production of clean alternative fuels, chemicals and electricity. Of the commercialized fixed bed gasifiers, BGL and Lurgi gasifiers are the most typical. In this paper, modeling, simulation and comparison of the coal to liquid fuels (CTL) process with BGL/Lurgi gasifier are conducted. For a typical CTL process with feeding rate of 852.74 t coal (dry)/h, Case BGL can produce Fischer-Tropsch (FT) liquids of 212.61 t/h, while Case Lurgi can produce 168.48 t/h. Case BGL demonstrates higher energy efficiency (44.91%) than Case Lurgi (41.21%) due to the higher syngas yield of BGL gasifier. The corresponding exergy efficiencies are 44.65% for Case BGL and 40.27% for Case Lurgi, respectively. The exergy losses of the subsystems are quantitatively analyzed and the measures to reduce exergy losses are proposed. The techno-economic and CO2 emission analysis are investigated. Finally, the performances of fixed bed and entrained flow gasifiers for CTL process are compared. It is found that gasification has an important influence on the thermodynamic efficiency, economics, and CO2 emission, and this research is useful for gasifier selection in the CTL process.

Solar fuels from supercritical water gasification of algae: Impacts of low-cost hydrogen on reformer configurations

Liquid transport fuels produced from biomass are of growing importance, due to increasingly ambitious targets for CO2 emissions reduction. However, a mismatching hydrogen-to-carbon ratio in biomass feedstocks, versus that required for conventional fuels, requires that supplementary hydrogen be added or surplus carbon be removed in the production process, with many possible process configurations. Here, we consider these alternative configurations for a process incorporating a supercritical water gasification reactor, syngas reformer and downstream Fischer–Tropsch liquid fuel synthesis unit. The feedstock is microalgae, process heat is supplied using a concentrating solar-thermal collector, and additional hydrogen is supplied from photovoltaics-powered electrolysers. Using a dynamic techno-economic process model to capture solar resource dynamics, configurations are optimised for lowest produced fuel cost. Three syngas reformer types are considered: steam methane reforming (SMR), with solar heat driving the conversion of CH4 into syngas; partial oxidation/dry reforming (PO/DR), with added hydrogen instead serving that same purpose; and autothermal reforming (ATR), combining both H2 and heat. Furthermore, for SMR, both CO2 dumping and H2 addition cases are considered. At present-day 9.72 AUD/kg hydrogen costs, SMR with CO2 dumping is cheapest, yielding gasoline equivalent at 3.76 AUD/L. With cheaper hydrogen, the optimal configuration shifts to SMR with H2 addition, then ATR, then PO/DR, reaching a fuel cost of 2.99 AUD/L at H2 cost of 2.1 AUD/kg. The design of future biofuels processes will depend greatly on the cost of hydrogen.

Performance and cost analysis of liquid fuel production from H2 and CO2 based on the Fischer-Tropsch process

Electro-fuels can be produced from concentrated sources of carbon dioxide and hydrogen using electricity generated from renewable sources; this process enables energy storage at high volumetric energy density. Among the electro-fuels options, FT (Fischer-Tropsch) fuel is attractive for heavy-duty trucks and non-road transportation applications. The present study conducts a techno-economic analysis of FT liquid fuel production from H2 and CO2 using a detailed performance analysis. Minimum fuel selling price is estimated for a broad range of H2 and CO2 prices and for a range of potential CO2 credits. The analysis indicates that H2 price has the largest impact on the minimum selling price of FT fuel. FT fuel production with a CO2 price of $17.3/metric ton requires an H2 price of $0.8/kg to be cost-competitive with the pre-tax petroleum diesel price of $3.1/gal in 2050 (before the application of any CO2 credits). When the H2 price is $2.0/kg from central water electrolysis (2020 target), the minimum selling price of the FT fuel is $5.4–5.9/gal. A sensitivity analysis shows that future system optimization of FT fuel production could focus on improving the H2 and CO2 recycle contributions and FT fuel conversion ratio. The analysis results can be combined with various upstream systems for H2 and CO2 production.

GIS-based modeling of residual biomass availability for energy and production in Mexico

Energy demand in Mexico is expected to increase in the foreseeable future; however, recently adopted national policies require that Mexico reduces its dependence on fossil fuel-based energy resources. In order to identify areas with a high potential for renewable energy production, based on agricultural by-products a geographic information system-based model was constructed. The model considered a set of enablers' layers (agriculture residue, roads, electrical network, population, land use) and a set of restrictors' layers (slope, natural protected areas, water bodies, natural vegetation, populated areas, airports, and historical sites). Eight crops were selected: maize, wheat, sugarcane, barley, sorghum, agave, paddy rice, and pecan nut. These were selected based on their residue production, as well as being the ones with sizable production volume in several regions across Mexico, as well as the characteristics of their residual biomass that can be used for generating energy or chemicals, without altering the primary intention for these crops, which is human and animal feed. Four models were developed using a weighted overlay algorithm to construct the enablers' layer while the restrictors' layer was created by selecting features with a given characteristic or by generating buffers from the layer's features. The results show that it is possible to generate up to 70,951 MWh of electricity or 18,373 Gg of Fischer–Tropsch liquids using only 60% of the residual biomass. The distribution of these energy sources in the country is highly variable depending on the type of crop selected with a concentration of the crop residues along the lowlands of the Gulf of Mexico and the Pacific Ocean and the central states of Guanajuato, Jalisco, and Queretaro. The study covers a very ample set of municipalities throughout the country, therein their relevance.

Experimental and numerical study into the effects of passive flow disturbance on conversion and C7+ yield of the packed bed Fischer Tropsch reaction

This experimental and numerical study investigates the effect of flow field alteration via bluff body flow disturbers in the packed bed Fischer-Tropsch (FT) reaction, which is known to be limited by heat and mass transfer and chemical kinetics as prescribed by the reactor geometry, flow and temperature fields, and catalyst properties. Experiments were carried out using a 188 cm3 reactor with 30.8 aspect (length-to-diameter) ratios loaded with 20% cobalt/Al2O3 catalyst and controlled at 200 °C at the exterior wall. Numerical simulation was carried out in the commercial ANSYS Fluent package. Experimental results show that the bluff bodies increased the CO (carbon monoxide) conversion and C7+ yields (hydrocarbons with 7 carbon chains or longer) across the factorial design space by as much as 1.8× and 3.3× of the baseline values, respectively. Numerical simulations suggest that these increases can be attributed to higher thermal conductivities and local velocities for greater heat rejection and lower external mass transfer resistance, respectively. Results suggest that the use of internal flow disturbers in the packed bed had significant influence in lowering the heat and mass transfer resistances of the FT process, and can improve the cost-competitiveness of FT liquids production in the small scale.

Biomass gasification: conversion of forest residues into heat, electricity and base chemicals

Gasification of biomass can play a major role in the future’s energy system as a source of renewable electricity, process heat, fuels, and chemicals. The composition of wood poses some constraints for the operation: below a certain limit of gasification agent, parts of the carbon stay solid and must be considered as an efficiency loss. Thermodynamic calculations allow the determination of this solid carbon boundary and give hints for the process optimization. Several examples for gasifiers, gas cleaning approaches—primarily focusing on tar as the main operating difficulty and dust—and producer gas applications are given and evaluated, including some aspects of scale. Finally, the great potential for the production of transportation fuels and base chemicals from renewable resources is discussed. Possible products are methane, methanol, dimethyl ether, gasoline, Fischer–Tropsch liquids and mixed alcohols. If installations for the gasification of woody biomass with chemicals production are combined with water electrolysis from renewable electricity, the carbon conversion efficiency of the process will be raised to 100% or the combined PBtX-installation (Power and Biomass to X) will offer significant balancing power to the electricity transmission network.

Enviro-economic assessment of thermochemical polygeneration from microalgal biomass

This paper presents a model-based assessment of the thermochemical conversion of microalgal biomass into Fischer-Tropsch liquids, hydrogen and electricity through polygeneration. Two novel conceptual plants are investigated, which are both comprised of the same operation units (gasification, water-gas shift, Fischer-Tropsch synthesis, upgrading, separation, Rankine cycle and gas turbines) and mainly differ in the location of the water-gas-shift unit. Both plants are found to present a carbon efficiency greater than conventional biomass-to-liquid processes. The most profitable plants in terms of the saleable products yields ca. 0.23 m3 (1.4 bbl) of liquid transportation fuels (gasoline, kerosene and diesel), ca. 16 kg of hydrogen (716.8 scm), and ca. 1.55 × 109 J (430 kW·h) of electricity per 1000 kg of dried microalgae. The corresponding displaced fossil fuels could offset the carbon emissions by 0.56 kg of carbon dioxide for every kg of processed dried microalgae. Nevertheless, predicted break-even prices are lower than 40 USD per ton of dried microalgae in the base case scenario, which is at least 10 times cheaper than the current best scenario for microalgal biomass production. These low prices are a major impediment to the viability of these thermochemical polygeneration plants, albeit presenting a good potential toward cleaner liquid fuel production.

Co‐doped ZnO thin films grown by pulsed electron beam ablation as model nano‐catalysts in fischer‐tropsch synthesis

A single‐step deposition of cobalt‐doped zinc oxide (Co‐ZnO) thin film nano‐composites on three different crystalline substrates, viz., Al2O3 (c‐sapphire), silicon (100) (Si), and SiO2 (quartz) is reported, using pulsed electron beam ablation (PEBA). The results indicate that the type of substrate has no effect on Co‐ZnO films stoichiometry, morphology, microstructure, and film thickness. The findings show the presence of hexagonal close‐packed metallic Co whose content increases in the films deposited on Al2O3 and Si substrates relatively to SiO2 substrate. The potential of the films as model nano‐catalysts has been evaluated in the context of the Fischer‐Tropsch (FT) process. Fuel fractions, which have been observed in FT liquid products, are rich in diesel and waxes. Specifically, Co‐ZnO/Al2O3 nano‐catalyst shows a selectivity of ∼4%, 31%, and 65% towards gasoline, diesel, and waxes, respectively, while Co‐ZnO/SiO2 nano‐catalyst shows a selectivity of ∼12%, 51%, and 37%, for gasoline, diesel, and waxes, respectively. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3332–3340, 2018

Mobile Autothermal Pyrolysis System for Local Biomass Conversion: Process Simulation and Techno-Economic Analysis

This paper presents a mobile autothermal pyrolysis system for locally converting biomass feedstock into bio-oil that can be transported easily. The system includes a compact internally interconnected fluidized bed (IIFB) reactor, a biomass pretreatment facility, and a product recovery unit. On the basis of modified chemical kinetic models, the pyrolysis process of common forestry and agricultural residues in this mobile system has been simulated. The pyrolytic product distribution from simulation has good agreements with experimental results. Then, the techno-economic performance of the mobile pyrolysis system in China is evaluated and compared with other liquid biofuel production facilities, i.e., fixed biomass pyrolysis plants and Fischer–Tropsch liquids production via biomass gasification (BG-FT). The results indicate that the biomass feedstock cost of mobile pyrolysis systems can be effectively reduced. Compared with the fixed biofuel production plant, the labor cost is higher for the mobile plant. Th...

Options for the conversion of pulp and paper mill by-products in Western Canada

The pulp and paper industry, one of Canada’s largest and most important industries, produces many by-products, some of which are used to produce electricity and steam for mill operations; however, the by-products are not used economically. The industry has been facing financial challenges and, therefore, an appropriate means of converting by-products to value-added products is highly desired. In this study, we explore nine pathways for the conversion of black liquor, the major by-product of the industry, to different value-added final products. These include steam, electricity, dimethyl ether, Fischer-Tropsch liquids, mixed alcohols, methanol, acetone, butanol, ethanol, and lignin. The most economical conversion pathway is selected based on the internal rate of return (IRR) calculated through a techno-economic assessment. Lignin production through the fractionation of black liquor is the most attractive scenario. Sensitivity and uncertainty analyses were performed on the IRR for the lignin production scenario to evaluate the effect of different parameters on overall performance and assess the accuracy of the results. The sensitivity analysis shows that lignin price and operating costs are the most influential parameters on IRR. This study offers insights into options of revenue generation for the pulp and paper industry through the innovative use of its by-products.

System Optimization for Fischer–Tropsch Liquid Fuels Production via Solar Hybridized Dual Fluidized Bed Gasification of Solid Fuels

A new configuration of solar hybridized dual fluidized bed (DFB) gasification process is proposed with char separation for the production of Fischer–Tropsch (FT) liquid fuels from solid fuels of biomass and/or coal. The addition of carbon capture with sequestration and FT reactor tail-gas recycle configurations is also assessed. The studied FT liquid fuels production systems are simulated by using a pseudodynamic model incorporating a year long, hourly averaged solar insolation time-series. For the case with a solar multiple (i.e., the heliostat field area relative to that required to meet the demand of the DFB gasifier at the point of peak solar thermal output) of 2.64 and bed material storage capacity of 16 h, the calculated annual solar share of the solar hybridized coal-to-liquids system can be increased from 12.2 to 20.3% by the addition of the char separation for a char gasification conversion of 80%. To achieve the well-to-wheel greenhouse gas emissions for FT liquid fuels parity with diesel derive...

Techno-economic analysis of production of Fischer-Tropsch liquids via biomass gasification: The effects of Fischer-Tropsch catalysts and natural gas co-feeding

The effects of H2/CO ratio in syngas from a biomass gasifier, the type of a Fischer-Tropsch (FT) catalyst, addition of a reformer in a recycle mode, efficiency of CO2 removal, and co-feeding of biomass and natural gas on the overall thermal efficiency and costs for the production of FT liquid fuels from the biomass-derived syngas were analyzed using an Aspen Plus®-based process model. The overall thermal efficiency for biomass-fed processes was in a range of 41.3–45.5%. A cobalt catalyst-based FT process achieved slightly higher efficiency than an iron-based FT process mainly owing to the absence of water-gas shift activity on a cobalt FT catalyst. A proper amount of CO2 in the syngas can inhibit the amount of CO2 generated via the water-gas shift reaction in a FT reactor with an iron-based catalyst which yields a similar efficiency to a cobalt-based FT process. The lowest production costs were around $28.8 per GJ of FT liquids for the biomass fed processes with a reformer. However, the addition of a reformer in the gas recycle loop can improve the economics only when the operation of the plant is optimized for maximum fuel production rather than co-generation of fuels and power. A process with co-feeding of natural gas into the reformer can achieve more attractive economics than a solely biomass fed process. Co-feeding of biomass and natural gas each at 200MWth for a total feedstock thermal energy input of 400MWth reduced the costs of FT liquid production by about 30% to $19–$20 per GJ of FT liquids. However, production of FT biofuels would be economically viable only at very high oil price or if some premiums are considered for the production of green fuels and power. At an oil price of $60/barrel, production of FT biofuels in the process configurations considered in this study wouldn’t be economically feasible.

Biorefinery for the Production of Biodiesel, Hydrogen and Synthesis Gas Integrated with CHP from Oil Palm in Malaysia

Abstract Malaysia is presently the world’s largest exporter of palm oil with total production of 19.22 million tonnes of crude palm oil (CPO) in 2013. Aside CPO, by-products such as empty fruit bunch (EFB), palm kernel shell (PKS), palm kernel oil (PKO), palm kernel cake (PKC) and pressed palm fibres (PPF) are produced from the palm oil mills. These biomasses can be used as potential feedstock for the production of biofuels, biogas and bioelectricity. One of the ways to fully harness the potentials of these biomasses is by employing the biorefinery concepts where all the products and by-products from oil palm are utilized for production of valuable bio-products. In this study, technological feasibility of biorefinery for the production of biodiesel, hydrogen, Fischer-Tropsch liquids (FTLs) integrated with combined heat and power (CHP) generation was investigated. Flowsheet was designed for each of the processes using Aspen HYSYS® v 8.0. Material balance was performed on a palm oil mill processing 250 tonnes per year of fresh fruit palm (FFP). Results from the material balance shows that 45.1 tonnes of refined bleached deodorized palm oil (RDBPO) and 52.4 tonnes of EFB were available for the production of biodiesel, hydrogen, FTLs and the CHP generation. The annual plant capacity of the biodiesel production is estimated to be 26,331.912 tonnes. The overall energy consumption of the whole process was estimated to be 36.0 GJ/h. This energy demand was met with power generated from the CHP which is 792 GJ/h leaving a surplus of 756 GJ/h that can be sold to the grid. The process modelling and simulation of the biorefinery process shows technological feasibility of producing valuable products from oil palm.

Comparison of Life Cycle Greenhouse Gases from Natural Gas Pathways for Light-Duty Vehicles

Low prices and abundant resources open new opportunities for using natural gas, one of which is the production of transportation fuels. In this study, we use a Monte Carlo analysis combined with a life cycle analysis framework to assess the greenhouse gas (GHG) implications of a transition to natural gas-powered vehicles. We consider six different natural gas fuel pathways in two representative light-duty vehicles: a passenger vehicle and a sport utility vehicle. We find that a battery electric vehicle (BEV) powered with natural gas-based electricity achieves around 40% life cycle emissions reductions when compared to conventional gasoline. Gaseous hydrogen fuel cell electric vehicles (FCEVs) and compressed natural gas (CNG) vehicles have comparable life cycle emissions with conventional gasoline, offering limited reductions with 100-year global warming potential (GWP) yet leading to increases with 20-year GWP. Other liquid fuel pathways (methanol, ethanol, and Fischer–Tropsch liquids) have larger GHG emi...

Solar Hybridized Coal-to-liquids via Gasification in Australia: Techno-economic Assessment

The concept of solar hybridised coal-to-liquids is to produce transportation liquid fuels from the syngas obtained from gasification ofcarbonaceous feedstocks with the integration of concentrated solar thermal power (CSP). In the present study, a techno-economic evaluation of a coal-to-liquids processes integrated with a solar hybridised, oxygen blown, atmospheric pressure vortex-flow gasifier (SCTL) is compared with that of a reference, non-solar, pressurised entrained flow gasifier (CTL) based on the solar and coal resources in Australia. In comparison with conventional gasification systems, the proposed SCTL system reduces the input feedstock by 18% while maintaining the Fischer-Tropsch (FT) liquids output.Furthermore, with the addition of CSP to the CTL plant, a reduction in mine-to-tank (MTT) CO2 emissions by 26% can be achieved. This is due to the fact that the heat required to meet the endothermic gasification reactions is supplied by CSP when the sun is available, thus more coal was converted to syngas subsequently higher FT liquids. To produce 1500 barrel per day of FT liquids,the total permanent investment cost for the SCTL plant was estimated to be around $467-$493 million, depending on the solar site and the coal compared with the CTL plant of around $377-$384 million if the plant was to be built in year 2020. The levelised cost of fuel (LCOF) for the CTL plants was found to be around $40-$41/GJLHV and $46-$49/GJLHV for the SCTL plants. The LCOF for the plants is very sensitive to the total permanent investment cost, load factor and cost of carbon capture and sequestration. Furthermore, the LCOF for the SCTL plant is also very sensitive to the cost of the syngas storage.