Fuel Production Process Research Articles

Identification of Yarrowia lipolytica as a platform for designed consortia that incorporate in situ nitrogen fixation to enable ammonia-free bioconversion

Bioconversion processes require nitrogen for growth and production of intracellular enzymes to produce biofuels and bioproducts. Typically, this is supplied as reduced nitrogen in the form of ammonia, which is produced offsite from N2 and H2 via the Haber-Bosch process. While this has revolutionized industries dependent on fixed nitrogen (e.g., modern agriculture), it is highly energy-intensive and its reliance on natural gas combustion results in substantial global CO2 emissions. Here we investigated the feasibility of in situ biological nitrogen fixation from N2 gas as a strategy to reduce greenhouse gas impacts of aerobic bioconversion processes. We developed an efficient and cost-effective method to screen fungal bioconversion hosts for compatibility with the free-living diazotrophic bacterium Azotobacter vinelandii under nitrogen fixing conditions. Our screening revealed that the genus Yarrowia is particularly enriched during co-culture experiments. Follow-up experiments identified four Y. lipolytica strains (NRRL Y-11853, NRRL Y-7208, NRRL Y-7317, and NRRL YB-618) capable of growth in co-culture with A. vinelandii. These strains utilize ammonium secreted during diazotrophic fixation of N2, which is provided as a component of the air input stream during aerobic fermentation. This demonstrates the feasibly of in situ biological nitrogen fixation to support heterotrophic fermentation processes for production of fuels and chemicals.

Feasibility of continuous water and carbon dioxide splitting via a pressure-swing, isothermal redox cycle using iron aluminates

Efficient solar thermochemical fuel production has been hindered by either solid–solid heat recuperation and material stability challenges associated with conventional temperature swing operation or low reactant conversion associated with isothermal operation. Increasing the oxidation pressure has emerged as a method for achieving efficient and practical solar-to-fuel conversion with certain redox mediators. When coupled with isothermal operation, pressure-swing redox cycling with iron aluminates eliminates irreversible heating penalties associated with large temperature swings while simultaneously enabling greater reactant conversion. However, remaining questions persist regarding 1) kinetics, 2) co-splitting capabilities, and 3) continuous processing prior to implementation beyond the lab scale. Here, we provide mechanistic insight on how pressure impacts the oxidation kinetics of iron aluminates, demonstrate syngas production with H2:CO ratios ranging from 1.3 ± 0.05 to 3.2 ± 0.25, and produce fuel continuously over an eight-hour period using dual fluidized bed reactors to evaluate the key considerations for large scale implementation. This work demonstrates the feasibility of a continuous solar thermochemical fuel production process via pressure-swing, isothermal redox cycling.

Predictive analysis of methane-enhanced conversion of organic waste into sustainable fuel: A machine learning approach

Currently, methane-assisted biomass-to-fuel (M-BtF) processes are being introduced, which are of considerable importance due to the production of an environmentally friendly fuel. Due to the lower price, natural gas can address a stronger potential compared to hydrogen and nitrogen under pyrolysis and bio-oil upgrading processes. Based on this, it seems vital to evaluate such a clean fuel production process from the standpoints of the life cycle analysis (LCA) and techno-economic assessment to exhibit the economic feasibility and environmental superiority. This article aims to utilize machine learning (ML) to predict the yield of organic solid waste, evaluate its economic feasibility, and investigate the environmental sustainability of the valorization of a methane-assisted organic solid waste process. The study employs an artificial neural network (ANN) model with a semi-automatic tuning procedure to forecast the yield of bio-oil, based on biomass characterization. This approach eliminates the need for pilot plant trials for new types of biomass to determine process yields before industrial scale-up. The ANN model demonstrated a high prediction accuracy, achieving an R2 (coefficient of determination) value higher than 0.82. The simulation results, derived from the ML predictions, were then employed in the techno-economic analysis and LCA, where they were compared with other commercial processes for economic viability and environmental impact assessments. The minimum selling price for the renewable diesel was calculated as 3.45 US$/gallon, which is notably competitive, being around 26 % lower than the average minimum selling price observed in relevant publications. Based on Monte Carlo simulation, the plant's internal rate of return (IRR) remained above 50 % across various discount rates, suggesting a highly profitable investment. From LCA results, the proposed method was found to emit ∼ 67 % less greenhouse gases (GHG) compared to standard commercial processes. Overall, the study showcases how the integration of machine learning into process simulation can lead to both economically and environmentally beneficial outcomes, particularly in the context of renewable energy production.

ZSM‐5‐Promoted Co‐Based Light‐Assisted Thermocatalytic Fischer–Tropsch Synthesis Catalyst for Production of Liquid Fuel

Light‐assisted thermocatalytic Fischer–Tropsch synthesis (FTS) provides a more efficient and sustainable approach to synthesizing high‐value chemicals compared to the thermal‐driven FTS. However, producing liquid fuel via cobalt‐based light‐assisted thermocatalytic FTS catalyst poses a challenge since photogenerated electrons increase CO conversion simultaneously with a significant reduction in the selectivity of C5+ product. Herein, a cobalt‐based light‐assisted thermocatalytic FTS catalyst containing ZSM‐5 molecular sieve promoter is prepared by a unique wet chemical reduction method, and the constructed 15%Co/Ta3N5‐ZSM‐5 catalyst exhibits nearly 90% C5+ product selectivity and 63% CO conversion under photothermal condition. Further characterization indicates that the simultaneous increase in the number of active sites and the density of acidic sites in the catalyst is crucial to achieve a simultaneous increase in CO conversion and C5+ product selectivity, which enables the catalyst to produce liquid fuel via light‐assisted thermocatalytic FTS reaction. This work provides an approach to introduce solar energy into the process of liquid fuel production, which can improve the sustainability of the liquid fuel production process.

Konversi Limbah Biomassa Tandan Kosong Sawit menjadi Energi Panas

Biomass waste from palm oil mill processing in Indonesia, especially on the island of Sumatra one of which is Aceh Province, is currently quite abundant and has not been managed optimally. This biomass waste can be converted into solid energy, which can be used as energy for biomass power plants. The aim of this research is specifically to convert biomass waste into solid energy. This research applies Simultaneous compression with heating as a fuel production method. The biomass waste used as solid fuel production material is empty palm oil bunches. The results of the fuel production process based on palm oil biomass waste show that the energy value reaches 26.80 MJ/kg. The carbon content in the produced fuel reaches 47.56%, with a low ash content of 6.70%. Calculations of the density of biomass-based fuel before and after production show an average of 1.42 grams/cm3. The results of tests carried out on fuel produced using palm oil biomass waste show high energy potential that can be used to reduce dependence on the use of coal.

Impact of bioenergy feedstock carbon farming on sustainable aviation fuel viability in the United States.

Biomass-derived sustainable aviation fuel holds significant potential for decarbonizing the aviation sector. Its long-term viability depends on crop choice, longevity of soil organic carbon (SOC) sequestration, and the biomass-to-biojet fuel conversion efficiency. We explored the impact of fuel price and SOC value on viable biojet fuel production scale by integrating an agroecosystem model with a field-to-biojet fuel production process model for 1,4-dimethylcyclooctane (DMCO), a representative high-performance biojet fuel molecule, from Miscanthus, sorghum, and switchgrass. Assigning monetary value to SOC sequestration results in substantially different outcomes than an increased fuel selling price. If SOC accumulation is valued at $185/ton CO2, planting Miscanthus for conversion to DMCO would be economically cost-competitive across 66% of croplands across the continental United States (US) by 2050 if conventional jet fuel remains at $0.74/L (in 2020 US dollars). Cutting the SOC sequestration value in half reduces the viable area to 54% of cropland, and eliminating any payment for SOC shrinks the viable area to 16%. If future biojet fuel prices increase to $1.24/L-Jet A-equivalent, 48 to 58% of the total cultivated land in the United States could support a more diverse set of feedstocks including Miscanthus, sorghum, or switchgrass. Among these options, only 8-14% of the area would be suitable exclusively for Miscanthus cultivation. These findings highlight the intersection of natural solutions for carbon removal and the use of deep-rooted feedstocks for biofuels and biomanufacturing. The results underscore the need to establish clear and consistent values for SOC sequestration to enable the future bioeconomy.

Concomitant strain of Bacillus vallismortis BR2 and Escherichia coli Khodavandi-Alizadeh-2 for Biocatalytic Synthesis of Fatty Acid Methyl Ester from Waste Oil Feedstock

Bacillus vallismortis BR2 and Escherichia coli Khodavandi-Alizadeh-2 lipases (E.C.3.1.1.3) were used to produce fatty acid methyl ester (FAME), a sustainable source of fuel. The lipase activity was measured using the titrimetric method after it was extracted from a solid fermented substrate in phosphate buffer. The use of Central Composite Design to optimize condition parameters was examined, while qualitative and quantitative assessments of FAME samples were performed using GC-MS with MSD in scan mode and selective ion monitoring. Lipase activity peaked at 24 h and then declined as the incubation time went on. The independent variables, such as pH, temperature, agitation, incubation time and enzyme quantity, all had an effect on biodiesel yield since they were all significant in the rate of biodiesel yield. FAME yield increased significantly after adding 1 to 2 mL of enzyme and a pH range of 4.57143 to 7.42857, but thereafter declined. The chromatograms indicated a peak of cis-10-Heptadecanoic acid methyl ester with concentrations of 39.95 mg/L and 58.95 mg/L in the FAME molecules. The viscosity (3.67 m3/s), specific gravity (0.813 g/cm3), flash point (102.70 °C), cetane number (55.52), and pour point (-24 °C) of the fuel were also measured. The synthesized biodiesel from the spent oil through the synergic enzymes were found to be a simple, effective, and sustainable fuel production process, as well as a potential means of eliminating pollution caused by haphazard waste cooking oil disposal.

Microalgae Biofuel for a Heavy-Duty Transport Sector within Planetary Boundaries.

In this contribution, we study the extent to which 68 scenarios for microalgae biofuels could help the heavy-duty transport sector operate within planetary boundaries. The proposed scenarios are built considering a range of alternative configurations based on three types of fuel production processes (i.e., transesterification, hydrodeoxygenation, and hydrothermal liquefaction), different carbon sources (such as natural gas power plants and direct air capture), byproduct treatments, and two electricity mixes. Our results reveal that microalgae biofuels could significantly reduce the environmental and human health impacts of the business-as-usual (fossil-based) heavy-duty transport sector. Moreover, relative to standard biofuels that show large land-use requirements, we find that microalgae biofuels also decrease the damage on biosphere integrity substantially. Notably, pathways resorting to hydrodeoxygenation of microalgae oil and direct air capture and carbon storage could reduce the current impact induced globally on climate change by the heavy transport by 77%, while attaining six-fold reductions in biosphere integrity impacts, both relative to conventional biofuels.

Maximizing jet fuel production from n-hexadecane hydrocracking over Pt-supported Y catalysts: Importance of ideal hydrocracking characteristics

In the two-step vegetable oil hydroconversion into jet fuel, which is the current major bio-jet fuel production process, the hydrocracking of green diesel primarily determines the final yield. In order to maximize bio-jet fuel production from the above process, the hydroconversion of hexadecane, a model compound for green diesel, was comprehensively investigated over Pt-supported HY and dealuminated HY (HY-DA) zeolites in a fixed-bed reactor. Due to the well-developed mesopores and the lower acidity, Pt/HY-DA was closer to the ideal hydrocracking characteristics of high isomerization yields and limited secondary cracking compared to Pt/HY. Thus, Pt/HY-DA achieved almost ideal selectivity to jet fuel compared to Pt/HY, with maximum yields of 40.5 % and 29.9 % respectively. At >20 % cracking yields, both catalysts yielded jet fuels with >80 % isomer content, which satisfied the jet fuel specifications for low temperature cold flow properties. Also, Pt/HY-DA shows better catalyst stability relative to Pt/HY.

Modification of the Aeration-Supplied Configuration in the Biodrying Process for Refuse-Derived Fuel (RDF) Production

Biodrying is an essential part of the mechanical–biological treatment process that minimizes moisture content and simultaneously maximizes heating value for refuse-derived fuel (RDF) production. Although the mechanical separation process operates effectively in Thailand’s RDF production, high organic content levels and their degradation cause moisture contamination in RDF, producing wet RDF. Aeration is essential for an effective biodrying process, and can reduce RDF’s moisture content as well as increase its heating value. To maximize the biodrying effect, aeration should be optimized based on the waste conditions. This study proposes a modified aeration-supplied configuration for wet RDF biodrying. The aeration rate was modified based on the period within the biodrying operation; the first period is from the beginning until day 2.5, and the second period is from day 2.5 to day 5. The optimal aeration supply configuration was 0.5 m3/kg/day in the first period and then 0.3 m3/kg/day until the end of the process; this configuration yielded the greatest moisture content decrease of 35% and increased the low heating value of the biodried product by 11%. The final moisture content and low heating value were 24.07% and 4787 kcal/kg, respectively. Therefore, this optimal aeration-supplied configuration could be applied to meet the moisture content and low heating value requirements of the RDF production standard for Thailand’s local cement industry.

Strategies for flexible operation of power-to-X processes coupled with renewables

Power-to-X (PtX) is a large-scale, long-term energy storage approach for converting renewable electrical energy into various chemical fuels. Unlike conventional fossil fuel production processes that operate continuously, PtX processes encounter operational challenges due to fluctuations in renewable power supply. To improve the operational flexibility of PtX processes for industrial applications, it is crucial to develop systematic strategies that can adapt to these fluctuations, which will increase PtX's energy and cost efficiencies. This study comprehensively explores various strategies for flexible operation of renewable-powered PtX processes, which include the use of additional energy buffers and grid connections. Power and material allocation models are developed for PtX processes based on islanded; grid-assisted; and grid-assisted, bidirectional connections by using three possible energy buffers (i.e., hydrogen intermediate storage, Li-ion batteries, and Carnot batteries). Surrogate model-based optimization is performed to establish an economically optimal design for each case. A power-to-methanol process implemented in Kramer Junction, California is studied to investigate the effects of flexible operation strategies on process performance in terms of production cost, renewable penetration, and energy efficiency. The findings of this study offer new insights into the operational flexibility of PtX processes and provide general recommendations for improving the flexibility and performance of PtX, particularly with respect to the establishment of a grid connection and the selection of an appropriate energy buffer.

New Janus structure photocatalyst having widely tunable electronic and optical properties with strain engineering

Photoelectrochemical water splitting using solar energy, generating oxygen and hydrogen is one of the clean fuel production processes. Inspired by surface-dependent characteristics of Janus structures, a newly designed Janus monolayer Silicon Phosphorous Arsenide (SiPAs) was analyzed with Density Functional Theory (DFT) methods. Hybrid exchange-correlation functional (HSE06) combined with Wannier90-based analysis for electronic and optical properties of SiPAs reveals that it can act as a photocatalyst. SiPAs show an indirect bandgap of 1.88 eV, absorbing visible light range is 350 to 500 nm. The phonon spectrum confirms dynamic stability. The exciton binding energy is computed with GW/BSE methods. The electronic band edge positions are at -5.75 and -4.43 eV, perfectly straddling the water redox potentials. Interestingly the strain application modifies the bandgap and also non-homogenously widens the absorption band. A novel range of photocatalyst designs with Group IV-V elements with great promise for water-splitting, photovoltaic, and narrow bandgap semiconductor (optoelectronics) applications may be feasible.

Zr0.1/(Fe[sbnd]Ce) as highly efficient catalyst for direct synthesis of diethyl carbonate from ethanol with fermentation tail gas as CO2 raw material

In the production process of bioethanol, stripping is usually required to improve the production efficiency of ethanol, and the generated CO2 fermentation gas direct emissions contribute to increased carbon. Herein, we prepared Zrx/(FeCe) catalyst by co-precipitation method to catalyze CO2 and ethanol for production of diethyl carbonate (DEC). Compared with FeCe catalysts, the introduction of Zr significantly improved the acid-base active sites and the oxygen vacancies on the catalyst surface, resulted in higher activity and selectivity of the catalysts. The ratio of Zr:(FeCe) in the catalyst, reaction temperature, pressure and time were optimized, resulting a high DEC selectivity of 96.7% under the Zr0.1/(FeCe) catalyst. Finally, we used the fermentation tail gas as CO2 source to react with ethanol for the formation of DEC, and obtained 56.0% selectivity of DEC. This study provides a new idea for the utilization of CO2 fermentation gas and the development of cleaner fuel production process.

Manifold improvement of water oxidation activity of NaCoO2 by selective cation exchange

Water oxidation produces electrons, protons, and oxygen, essential components in fuel production processes like CO2 reduction and hydrogen generation. To date, less cost and more-abundant catalysts showed low activity for the water oxidation reaction. Herein, we developed a simple and effective way to selectively exchange Na+ with H+ in NaCoO2 and created high surface area layered materials for efficient water oxidation. The photochemical water oxidation reaction activity improved from 0.9 × 10−3 s−1 (pristine NCO) to 2.90 × 10−3 s−1 (AT-NCO-2M). The electrochemical overpotential decreased from 600 to 370 mV, and the Tafel slope dropped from 93 to 47 mV/dec. Enhanced water oxidation activity is owing to delamination of stacked layered structure into few layer structure, increased surface area, super hydrophilic nature, and coexistence of Co4+ and Co3+ species. Our findings show the importance of the exchange of Na+ with H+ in Na-based metal oxides for efficient water oxidation.

Energy, economic and environmental (3E) analysis for the renewable jet fuel production process

Blending conventional petroleum jet fuel with renewable fuel obtained from hydro-processing of cooking oil wastes can significantly reduce the carbon footprint of the aviation sector. Renewable jet fuel (RJF) remains for the most part more expensive than conventional jet fuel and the life-cycle emissions reduction depends on the feedstock. For promoting mass production of used cooking oil (UCO) based jet fuel, a 3E (energy/exergy, environmental and economic) analysis of a simulated processing plant is carried out. Hydrogen is the main component in the two-step process: hydro-processing and hydro-cracking/isomerization. Hydrogen production and exergy destruction in the process significantly influence the life-cycle emissions of the RJF. The low exergy efficiency of the process units where significant heat transfer occurs generates an increase in the price of the products. Results show a life-cycle carbon dioxide emissions reduction from 41 % to 81 % when combusting the hydro-processed jet fuel instead of conventional jet fuel. The minimum fuel selling price could be very close to conventional jet fuel (about 18 % more expensive) if an effective cooking oil wastes collection system is in place. Moreover, when implementing a carbon tax above $37/tCO 2 the price becomes equal to conventional jet fuel. UCO is the most sustainable feedstock as there is no competition with the food market and the environmental benefits justify government spending for promoting mass production.

Lifecycle Environmental Benefits with a Hybrid Electric Propulsion System Using a Control Algorithm for Fishing Boats in Korea

In Korea, fishing boats account for 65,452 out of 71,174 coastal ships, and aging ships are a leading cause of environmental problems and economic loss. To solve this problem, the government has enacted a policy to promote the development and distribution of environmental vessels. Electric propulsion systems and hybrid systems are suggested as alternatives. However, to study whether this hybrid system is environmentally friendly, a system for measuring the performance of conventional diesel-powered ships was developed and measured. A case study applying the battery hybrid system was analyzed through a Matlab/Simulink simulation, and the effect of reducing the carbon dioxide emissions by 7.6% was verified. In addition, comparing with a case where the load-sharing optimal control was introduced, we proved that the carbon dioxide reduction with the controller was 10.7%. By applying the results of this study to various countries with different fuel production processes through the LCA technique, it was confirmed that the battery hybrid system is eco-friendly from the energy production stage, rather than unconditionally, according to the national power production method. Additional research is needed to reflect the aging trend of the entire fleet and to create a detailed category classification through future research.

The Operating Parameters, Structural Composition, and Fuel Sustainability Aspects of PEM Fuel Cells: A Mini Review

This mini review discusses the sustainability aspects of various fuels for proton exchange membrane fuel cells (PEMFCs). PEMFCs operate by converting the chemical energy in a fuel into electrical energy. The most crucial parameters in the operation process are the temperature, pressure, relative humidity, and air stoichiometry ratio, as presented in this work. The classical structure of a PEMFC consists of a proton exchange membrane, anode electrode, cathode electrode, catalyst layers (CLs), microporous layer (MPLs), gas diffusion layers (GDLs), two bipolar plates (BPs), and gas flow channels (GFCs). The mechanical behavior and the conductivity of the protons are highly dependent on the structure of the MEAs. This review discusses the various fuels and their production paths from sustainable sources. For the fuel production process to be renewable and sustainable, a hydrogen electrolyzer could be powered from solar energy, wind energy, geothermal energy, or hydroelectric energy, to produce hydrogen, which in turn could be fed into the fuel cell. This paper also reviews biomass-based routes for sustainable fuel production.

ANALISIS PENGENDALIAN JUMLAH CRUDE OIL SEBELUM DAN SESUDAH PANDEMI COVID-19 DENGAN PENDEKATAN ECONOMIC ORDER QUANTITY

Inventory control is a main activity for managing the amount of raw material inventory of the industry production process. PT. Pertamina RU II Dumai which engaged in oil and gas business activities have used Crude Oil as the major raw material in the fuel production process. Based on preliminary observation, it was found that the demand for avtur fuel was unstable during the period 2019-2020, decreasing to 54% whereas diesel fuel increasing to 17%. Consequently, this has an impact on the number of Crude Oil orders and also the inventory management. This study aims to determine the optimal amount of inventory, safety stock, the reorder point, and the ratio analysis of the amount raw material used during the era before and after pandemic covid-19 situation 2019 to 2020. Economic Order Quantity (EOQ) approach is proposed to place orders in the amounts that best fit its needs. The results of this study indicate that the number of purchases of raw materials using the EOQ method in 2019 and 2020 amounted to 3,525,563,777 BBL and 2,427,392.443 BBL. Total safety stock in 2019 was 10,031,979.39 BBL, while in 2020 it was 8,733,637.21 BBL. The number of reorder points in 2019 was 3,035,881,925 BBL and in 2020 it was 2,321,768,481 BBL. Regarding to this economic purchase of raw material quantity, it is found that the order size of Crude Oil decreased around 31.1% after the pandemic hit.

Direct production of polyhydroxybutyrate and alginate from crude glycerol by Azotobacter vinelandii using atmospheric nitrogen

While biodiesel is drawing attention as an eco-friendly fuel, the use of crude glycerol, a byproduct of the fuel production process, has increasingly become a concern to be addressed. Here we show the development of a low-cost fermentation technology using an atmospheric nitrogen-fixing bacterium to recycle crude glycerol into functional biopolymers. Azotobacter vinelandii showed substantial growth on tap water-diluted crude glycerol without any pretreatment. The number of viable A. vinelandii cells increased over 1000-fold under optimal growth conditions. Most of the glycerol content (~ 0.2%) in the crude glycerol medium was completely depleted within 48 h of culture. Useful polymers, such as polyhydroxybutyrate and alginate, were also produced. Polyhydroxybutyrate productivity was increased ten-fold by blocking the alginate synthesis pathway. Although there are few examples of using crude glycerol directly as a carbon source for microbial fermentation, there are no reports on the use of crude glycerol without the addition of a nitrogen source. This study demonstrated that it is possible to develop a technology to produce industrially useful polymers from crude glycerol through energy-saving and energy-efficient fermentation using the atmospheric nitrogen-fixing microorganism A. vinelandii.

Green coconut fiber thermal behaviour under the presence of a cobalt spinel catalyst

With increasing environmental concerns, much effort has been spent in research regarding development ofsustainable processes for production of fuels and chemical products. In this context, hydrothermal liquefaction (HTL)has gained increasing attention, as a possible route for the chemical transformation of organic raw-materials, some sortof biomass, for example, into liquid oils at temperatures usually below 400 °C, under moderate to high pressures (5–25MPa), usually in the presence of a suitable catalyst. In the present work the thermogravimetric (TG) behavior underinert atmosphere of pure green coconut fiber and mixtures thereof with a spinel phase (Fe2CoO4), acting as catalysthas been studied. Spinel samples have been produced at 1,000 °C and different calcination times (3 h, 6 h and 9 h). Bothraw and synthesized materials were characterized through different techniques, such as scanning electron microscopy(SEM), X-ray diffraction (XRD) and Infrared Absorption Spectroscopy (FTIR). According to the TG data, the catalystproduced during a calcination time of 9 h showed a superior behavior regarding the lignin full thermal decomposition,which developed without fixed carbon formation. The results further suggest that the mixing process has a significanteffect over the measured degradation kinetics, as it has a direct influence over the contact between catalyst and fibers.The kinetic modelling applied to the dynamic TG signal allowed a quantitative representation of the experimental data.The global process activation energy and order have proven to be respectively, 85.291 kJ/mol and 0.1227.