Commercial Fuels Research Articles

Electrochemical Modeling of a Commercial Polymer Electrolyte Fuel Cell Using 3-D Micro-Computed Tomography

Challenges remain with the accurate modeling and optimization of gas transport in polymer electrolyte membrane fuel cells (PEMFCs) due to the complexity of calculating transport across the relevant domains and structures in a fuel cell. Each cell comprises two bipolar plates (BPPs) compressed around a membrane electrode assembly (MEA). The bipolar plates (BPPs) are a multifunctional component having flow fields with mm-sized features designed for reactant delivery and heat and water management. The MEA comprises a 5-layer structure with microporous catalyst and gas diffusion layers (GDLs) on either side of a proton exchange membrane (PEM). Actual cell designs are further constrained by their materials, and manufacturing cost and speed.Prior work primarily focuses on modeling the flow fields in metal BPPs as idealized geometries, neglecting the inherent curvature introduced during the stamping manufacturing process and the compression and thickness variation of the MEA layers. To create high-performance cells, it is necessary to understand the detailed interaction of the BPPs and MEAs in practical, manufactured fuel cell stacks.In this work, a compressed short stack of unit cells from a decommissioned commercial fuel cell electric vehicle (FCEV) was resolved in three dimensions (3-D) using a micro-computed tomography instrument (micro-CT) capable of imaging large samples (up to 30 cm). Representative images from across the cell domains are shown in Figure 1. The 3-D images were subsequently segmented and meshed for computational fluid dynamics (CFD) modeling. Simulations of transport and electrochemical phenomena were performed using commercial CFD software using custom codes. Simulation results were used to assess the performance of a mesh-type cathode flow field design with secondary flows as well as the impact of compression, and stamped plate curvature. The results highlight the significant impact of the induced convective transport in the gas diffusion layers (GDLs) has on the performance of a practical fuel cell.Acknowledgements: This material is based upon work supported by Plug Power Incorporated.Figure Collage: Left – 3D Micro-CT Images of the BPPs and components of an MEA, Center - Meshing faces, Right – Relative Humidity Profile Figure 1

Delving into textile fast pyrolysis: A holistic study on the effects of feedstock and temperature variability

Perpetual fast fashion wave, dismal global recycling rate, and poor circularity of textiles urged sustainable textile waste disposal solution in lieu of incineration and landfilling. Herein, textile fast pyrolysis was mooted as a promising solution by dint of its fast disposal rate, mild pollutant emission, and multiple value-added products formation. Following ill-defined thermochemical behaviour of individual textiles, in-depth experimental exploration on textile fast pyrolysis was supplemented by feedstock characterization, product distribution, and product characterization to unravel the effects of feedstock (natural/synthetic) and temperature (500–900oC) variability on pyrolysis products. Textile fast pyrolysis harnessed pyrogas with two variable products, viz. retrievable chars and oils [natural textiles: cotton (C), denim (D), & cashmere/plant fibre (CP)] or non-retrievable chars and waxes [synthetic textiles: polyester (P), P/acrylic (PA), & P/cotton (PC)]. Melting and high aromaticity of polyethylene terephthalate (PET) rendered the synthesis of non-retrievable chars and waxes, separately. Given monotonic char yields (7.31–24.19 wt%) reduction with temperature, the oil/wax (53.19–75.19/60.46–70.52 wt%) and gas (13.44–33.67 wt%) yields were negatively correlated to each other. Twill-woven network of D contributed to exclusively high BET surface area of D chars (132.64–217.10 m2/g). All natural textile chars (28.56–32.88 MJ) exhibited comparable higher heating value (HHV) to commercial coals/coke (14.77–34.39 MJ/kg) and biochars (7.26–33.37 MJ/kg). Compared to the commercial fuels, raw textile oils (incombustible-10.14 MJ/kg) and textile waxes (15.88–23.18 MJ/kg) were inferior fuels with low HHV. Nonetheless, cotton (C & D) oils, CP oils, and P-based textile waxes had respective enriched content of levoglucosan (6.85–34.38 area%), triacetoneamine (6.22–21.09 area%), and benzoic acid (16.37–46.55 area%). Considering noteworthy H2 formation data sets (700–900oC; C700 only), natural textile pyrogas (62.75–79.02%) had greater syngas (H2 & CO) composition than synthetic textile pyrogas (62.48–68.23%). At optimal temperature of 900oC, textile fast pyrolysis generated pyrogas with H2:CO ratios (1.30–3.49 ≈ 2) that nearly ideal for Fischer-Tropsch synthesis. Conversely, textile fast pyrolysis also emitted pollutant gases that differ between natural (NH3, N2O, NO, & SO2) and synthetic [NH3 (excluding P), N2O, & NO2] textiles.

Particle emission and thermal efficiency analysis of a diesel vehicle using biodiesel and a platinum metallic partial-flow particulate filter

Harmful emissions from diesel vehicles, particularly unmodified ones, pose significant concerns for human health and the environment, underscoring the urgency to address these issues. This study investigated the effects of commercial fuels, B10, B20, and biodiesel B100, used with a metallic partial-flow catalyzed diesel particulate filter (P-CDPF), on a light-duty unmodified diesel vehicle's thermal efficiency and emissions characteristics. The initial test was conducted on a chassis dynamometer to measure the fuel flow rates at three different engine speeds, 1500, 2000, and 2500 rpm, with four loads, 84, 112, 140, and 160 Nm. This was done to evaluate brake-specific fuel consumption and brake thermal efficiency under steady-state conditions. The second test followed the new European driving cycle to examine emission factors of regulated pollutants under both urban and highway driving conditions. The results indicated that BSFC values increased with the biodiesel ratio in the blends, attributed to lower heating values. However, higher oxygen contents with increasing biodiesel ratios led to more complete combustion and improved brake thermal efficiency. Installation of a P-CDPF had a minimal impact, resulting in less than a 3.4% increase in the BSFC and a 1% decrease in brake thermal efficiency across all tested fuels, owing to its relatively low pressure drop. Increasing the biodiesel ratio from B10 and B20 to B100 resulted in reductions of up to 32% of particulate mass and 45% of particulate number in vehicle emissions. P-CDPF installation further reduced particulate mass by over 60% and particulate number by 36% across all tested fuels, demonstrating its effectiveness in trapping and passively oxidizing particulate matter. Furthermore, the P-CDPF significantly reduced harmful gases with addition of a catalytic coating. A combination of a P-CDPF and commercial biodiesel fuels emerges as an effective solution for reducing regulated emissions from unmodified diesel vehicles.

Effects of the use of acetone as co-solvent on the financial viability of bio-crude production by hydrothermal liquefaction of CO2 captured by microalgae

Hydrothermal Liquefaction (HTL) is a promising technology to produce biocrude from microalgal biomass that has captured gaseous CO2. However, several problems of this technology must still be solved to make it economically and technically feasible. One of the main problems in the financial viability of the HTL process is the low yield obtained when only water is used as a solvent, with results close to or lower than 30 wt%. This, in turn, increases the production cost to over 120 USD/BBL. In recent years, some authors have focused their efforts on increasing biocrude production through the extensive use of organic solvents, without considering the effects on economic viability. The present work evaluated the financial effect of using acetone as an organic co-solvent, finding that high acetone contents increased operating costs of the process, mainly due to losses in its handling and recovery. On the contrary, very low acetone contents had very little effect on the biocrude yield. It was possible to establish that concentrations close to 5 wt% of acetone, mixed with water, resulted in a yield of about 60 wt% and a production cost of 50 USD/BBL of biocrude, with an energetic densification of 30.25 MJ/kg and 8.60∘ API, classifying it as heavy crude, which makes it necessary to include refining processes for heteroatom removal. Chemical characterization of biocrude revealed a high content of nitrogenous compounds (23.6 wt%) and oxygenated compounds (10.7 wt%), which have to be removed for the subsequent production of commercial liquid fuels. It is concluded that the use of a water-acetone mixture allows for obtaining positive operating profits, which helps to the high capital costs involved in this type of technology, making it more financially comparable with the conventional petroleum industry.

Enzymatic Transesterification Using Different Immobilized Lipases and its Biodiesel Effect on Gas Emission

Biodiesel, a third-generation bio-fuels, offering several advantages over regular diesel fuel. Waste cooking oil (WCO) emerges as an ideal feedstock due to its availability and easy accessibility. In this work, biodiesel is utilized from two different types of immobilized lipases: Rhizomucor miehei lipase (RMIM) and Candida antarctica lipase B (CALB). The impact of the molar ratio of oil to methyl acetate (1:3-1:12) was evaluated for both lipases, and the resultant biodiesel was tested in diesel engine. The enzymatic transesterification was carried out in ultrasonic assistance and the results showed that the greatest yield of 81.20% at 45℃, using CALB as a biocatalyst, 1.8% (w/v) lipase and oil to methyl acetate molar ratio of 1:12 within 3 hours. Triacetin, by-product was determined their concentration for each molar ratio and analyzed using FTIR range of 500cm-1 to 4000cm-1, revealing a significant absorption peak at 1238.90cm-1. Biodiesel was blended with commercial diesel fuel in varying quantities of 7, 10, and 20% by volume (B20). The results were compared to Industrial Diesel Fuel 7% (B7) and Commercial Diesel Fuel 10% (B10). NOx and CO2 emission drops as the percentage of diesel/biodiesel blends increases, supporting WCO as a cost-effective biodiesel feedstock with low petrol pollution.

Analyzing the influence of feedstock selection in pyrolysis on aviation gas turbine engines: A study on performance, combustion efficiency, and emission profiles

Commercial aviation is primarily reliant on fossil fuels, yet the depletion of these sources and the consequences of climate change necessitates the exploration of sustainable alternatives. The pyrolysis process offers a viable method for producing biofuels from various feedstocks. This research examines the combustion, emission, and performance characteristics of biofuels derived from agricultural residues, waste tyres, and plastics using pyrolysis. Pyrolysis oils derived from forestry or agricultural products exhibit high viscosity and moisture content, which impairs combustion efficiency and increases carbon monoxide (CO) from 70 % to 187 % and unburned hydrocarbon (UHC) emissions. Conversely, pyrolysis oils from plastics and waste tyres provide stable combustion with carbon monoxide and total hydrocarbon emissions (THC) comparable to those of commercial jet fuel. However, nitrogen oxide (NOX) emissions are significantly elevated from 57 % to 157 %. Engine performance tests demonstrated that forestry pyrolysis oils result in thrust loss due to their high viscosity value (14.3–113 mm2/s) and low calorific value (17.3–31.7 MJ/kg). In contrast, plastic and tyre pyrolysis oil perform similarly to commercial jet fuels but may potentially cause performance loss due to their high aromatic content (>47.67 %). Overall, upgrading the viscosity, moisture, and aromatic content of pyrolysis oils can enhance their suitability as alternative aviation fuels. These improvements could assist the aviation sector in achieving its carbon-neutral goals by making pyrolysis oils competitive with conventional jet fuels.

Removal of thiophene compounds from model fuel with supported copper on active carbon, adsorption kinetics, and isotherms

AbstractIn this study, the adsorption of thiophene compounds (TCs), including thiophene (T), benzothiophene (BT), and dibenzothiophene (DBT), from model fuels was investigated using modified activated carbon (AC). The model fuel, prepared as a single‐solute model at a concentration of 2000 ppm based on a mixture concentration of 3000 ppm, served as the basis for the adsorption experiments. Additionally, an examination of thiophene adsorption from commercial fuels, specifically kerosene, was conducted. Experimental data were used to calculate correlated parameters of adsorption isotherms, kinetic models, and the Fisher factor. The pseudo‐second‐order model demonstrated the best fit to the experimental data. Notably, the adsorbent consisting of 10% Cu+ supported on acid‐washed activated carbon (A1CN10) exhibited the highest adsorption capacity for TCs, achieving removal percentages of 78%, 96%, and 100% for T, BT, and DBT, respectively. Various methods were employed to investigate the physicochemical properties of the adsorbents, including N2 adsorption–desorption surface analysis (BET), scanning electron microscopy (SEM), X‐ray diffraction (XRD), and energy dispersive spectroscopy (EDS). Furthermore, the regeneration of the adsorbent was studied using two techniques: agitation and ultrasound.

Determining the preeminent plastic wastes in the production of petrol using pyrolysis method and its effectiveness as an alternative fuel

Abstract: This study aimed to determine which type of plastic – PET, HDPE, LDPE, PP, PS, and Others, produces most oil yield in terms of time of complete degradation, temperature and amount of plastics using a non-catalytic slow pyrolysis method; it also determined the physical characteristics of the oil yield in terms of its color and appearance; and it also aimed to determine which petroleum produced by different types of plastics are more efficient in terms of (a) production of oil and (b) combustion time. Production of oil and oil yield is presented in milliliters and percentage, respectively. Combustion time is expressed in seconds from the time of ignition to total disappearance of flame having 1ml of oil tested from each produced pyrolytic oil. Experimental-descriptive comparative method was used in determining the type of plastic that yields to most of pyrolytic oil. Based from gathered results, at constant temperature and amount of plastics, PS produced most petroleum at 29.5% oil yield followed by PP with 29%. While PET produced the least petroleum with 0.01% oil yield. Color varies at different types of plastics, given that PET and PP produces light brown color, LDPE produces light yellow while HDPE, PS and Others produces black color. PET, HDPE, PP, PS and Others produced liquefied petroleum while LDPE produces flammable wax product. PS produced most petroleum with 295ml (29.5%), and PET produced least oil with 1ml (0.01%). Combustion time varies at different types of plastics: PS at 145 seconds, PP at 141 seconds, HDPE at 115 seconds, Others at 78 seconds, LDPE at 77 seconds while PET produced non – flammable oil yield. Thus, PS is most efficient as an alternative fuel in terms of production and combustion time. For the betterment of similar study, future researchers are encouraged to test the pyrolytic oil yielded from different types of plastics in engine performance and machineries and the comparative performance to the available commercial fuels.

Study on the composition of gasoline fractions obtained as a result of waste tires pyrolysis and production bitumen modifiers from it

Waste tires pose a significant threat to the environment. On the other hand, they are a potential raw material for energy production. Pyrolysis is one of the most promising methods for utilizing waste tires in a circular economy. The aim of the research was to study in detail the composition of gasoline fractions obtained during waste tires pyrolysis, and to search for effective methods of their application/processing without the use of catalysts and scarce hydrogen. Pyrolysis of waste tires was carried out on a pilot-scale industrial unit with a productivity of up to 15 tons/day of raw material. The liquid pyrolysis products were separated into several fractions: boiling below 140 0C, boiling at the range of 140–200 0C and fraction boiling above 200 0C. The residual fraction, based on its performance indicators, can be used as a component in fuel oils. The gasoline fractions (<140 0C and 140–200 0C) cannot be used as components in commercial fuels due to their high content of unsaturated and aromatic compounds. The obtained components of the gasoline fractions were analyzed with the usage of infrared spectroscopy and/or chromatography. Modifiers were synthesized from the gasoline fractions to improve the adhesive properties of bitumen. It was found that the resulting products (residue after obtaining bitumen modifiers) contain lower amounts of aromatic and unsaturated compounds compared to the initial gasoline fractions. This will allow reducing the content of these harmful components in the further use of gasoline fractions. Addition of the received modifiers to road bitumen brand BND 70/100 in the amount of 1% wt. Makes it possible to obtain bitumen with improved adhesive properties of the BNDA 60/90 brand.

Thermal pyrolysis of a real plastic sample from small WEEE and characterization of the produced oil in view of fuel or feedstock uses

The possibilities of valorizing by pyrolysis a plastic fraction from small waste from electrical and electronic equipment (WEEE-R4) rejected by a material recovery facility have been assessed. The characterization revealed that WEEE-R4 was mainly composed of acrylonitrile–butadiene–styrene (ABS) and blends of polycarbonate (PC)-ABS (75 and 25 wt%, respectively) and had good physicochemical properties as feed for pyrolysis processes: high values for volatile matter (95 wt%) and low heating value (LHV, 35 MJ/kg) and low ash and moisture content (2.5 and 0.33 wt%, respectively). On the contrary, the high content of heteroatoms, in particular Br from brominated flame retardants, arose as source of concern. Thermal analysis coupled with evolved gas Fourier transform Infrared (FTIR) spectroscopy showed that WEEE-R4 degraded in two steps in the range 310–460 °C and mainly to the monoaromatic compounds phenol and styrene. Thermal pyrolysis at 400 °C was carried out in a bench-scale reactor and the yields of the products were 18 wt% solids, 58 wt% light oil, 16 wt% tar and 8 wt% gas. The gaseous fraction was composed mainly of CO2 (60 wt%), originating from the thermal degradation of PC. After removing CO2, the gas had a good LHV (32.5 MJ/kg) such to contribute for the 66 % to the energy required for the pyrolysis process of WEEE-R4. The properties of the light oil were evaluated by means of the same standard tests used for commercial fuels or crude oils. The results were interesting but far from the more refined gasoline and diesel oil, with the concentration of nitrogen and bromine even higher than the typical composition of petroleum. Nevertheless, this study shows that pyrolysis followed by a refining treatment such as, distillation is capable of producing monoaromatic hydrocarbon in significant amount (>30 wt%).

Evaluating the Impact of Personal Exposure to Emissions from Sustainable Commercial Heating and Cooking Fuels on Women in Rural Southern India and Their Alignment with Sustainable Development Goals

Evaluating the Impact of Personal Exposure to Emissions from Sustainable Commercial Heating and Cooking Fuels on Women in Rural Southern India and Their Alignment with Sustainable Development Goals

Determination of stabilizing additives in kerosenes by the multisensor stripping voltammetry method

Relevance. To ensure the operational reliability of equipment, an urgent task is to control the content of antioxidant and antiwear additives in engine fuel at all stages from its production to its intended use. At the stages of fuel use (storage, transfer, transportation, etc.), antioxidant additives can be used up due to natural oxidative processes that inevitably occur in the fuel. As for the antiwear additives, being surfactants by their nature, they can be adsorbed on the surfaces of the process equipment with which the fuel comes into contact. As a result, at the stage of intended use, the level of fuel quality can significantly decrease. Controlling the content of additives in the fuel at the stage of application will allow taking timely measures to restore the fuel quality and reduce the risks of accidents. Aim. To propose an approach to the analysis of the component composition of fuels, which makes it possible to control the content of additives. Objects. Samples of kerosene fractions that are used as the basis or components of commercial fuels of the TС-1 and RT brands produced by oil refineries, stabilizing anti-wear additives "Hi-Tech" and DNA (distilled petroleum acids). Methods. In the framework of the research devoted to solving the problem of operational control of the content of certain additives in various petroleum products, much attention was paid to the possibility of using voltammetry methods for these purposes. Voltammetry is a set of electrochemical methods of research and analysis based on the patterns of electric current flow through an electrochemical cell – an analytical system of two electrodes separated by an analyzed electrolyte solution. Analytical information using voltammetric methods is obtained on the basis of studying the dependence of the current strength in an electrolytic cell on the potential of the indicator microelectrode immersed in the analyzed solution, on which the analyzed reaction proceeds. Results. The paper introduces an approach to the analysis of the component composition of fuels by the multisensor stripping voltammetry method. This approach makes it possible to control the content of additives in the fuel. A feature of the electrochemical behavior of various grades of hydrogenated jet fuel was studied in order to develop a mobile express method for determining additives in them. The authors have developed a test system consisting of an aqueous solution of dimethylformamide (40%) with potassium chloride (0,1 M), cobalt, zinc and mercury cations (2,5×10–4 M). The analyzed fuel was introduced in a ratio of 30:1. The resulting mixture, 50 μl in volume, was mixed and applied to an indicator electrode for subsequent electrochemical measurements. The determination of additives in kerosene in the developed method was carried out by their influence on the peaks of the currents of dissolution of metals in the test system. In this case not only the task of determining the presence of additives in kerosene was solved, but also the problem of their identification.

Co-Pyrolysis of walnut shell and waste tire with a focus on bio-oil yield quantity and quality

In this study, a series of pyrolysis and co-pyrolysis experiments on waste tires and walnut shells were conducted under ideal conditions of 500 °C, 10 °C/min heating rate, and 60 min of retention time. Mixture samples with WS/WT: 3/1, 2/2, and 1/3 additive ratios were utilized in co-pyrolysis experiments. The results of the experiments showed that the WS/WT: 3/1 additive ratio samples were necessary to achieve the positive synergistic effect. A 52.57 ± 0.28 % efficient liquid product by mass was produced under these conditions on a dry, ashless basis, which has a significant production potential for the production of high pyrolytic oil. The co-pyrolytic organic phase of the fuel contains around 40 % light naphtha, 10 % heavy naphtha, and 30 % medium distillate by volume, according to atmospheric distillation experiments. Furthermore, it has been discovered that this product can be utilized as a gasoline or gasoline additive due to its IBP-72 °C boiling point range, 20 % distillate percentage, and immediate or inexpensive improvement. When these observations are taken into consideration, it is clear that the co-pyrolytic liquid can be utilized as a raw material input in the production of various of commercial liquid fuels as well as a variety of chemicals with high added value.

ПОЛІЕТИЛЕНОВІ ВІДХОДИ – СИРОВИНА ДЛЯ ОДЕРЖАННЯ КОМПОНЕНТІВ МОТОРНИХ ПАЛИВ

One of the options for utilization of polyethylene waste is low-temperature pyrolysis, the target product of which is pyrocondensate. In the work, the fractional composition and properties of the pyrocondensate of pyrolysis of polyethylene waste were studied. It was established that pyrocondensate and its fractions practically do not contain heavy metals characteristic of oil fractions. Pyrocondensate is divided into gasoline, diesel fraction and residue. The composition and properties of these fractions were studied in detail. X-ray fluorescence analysis and IR spectroscopic studies of pyrocondensate and its separate fractions were carried out. It was established that narrow fractions of pyrocondensate and residue can be used as components of commercial fuels only after additional processing.

(N-Alkyloxalamido)-Amino Acid Amides as the Superior Thixotropic Phase Selective Gelators of Petrol and Diesel Fuels.

(N-Alkyloxalamido)-amino acid amides 9-12 exhibit excellent gelation capacities toward some lipophilic solvents as well as toward the commercial fuels, petrol and diesel. Gelator 10 exhibits an excellent phase-selective gelation (PSG) ability and also possesses the highest gelation capacity toward petrol and diesel known to date, with minimum gelation concentration (MGC) values (%, w/v) as low as 0.012 and 0.015, respectively. The self-assembly motif of 10 in petrol and toluene gel fibres is determined from xerogel X-ray powder diffraction (XRPD) data via the simulated annealing procedure (SA) implemented in the EXPO2014 program and refined using the Rietveld method. The elucidated motif is strongly supported by the NMR (NOE and variable temperature) study of 10 toluene-d8 gel. It is shown that the triple unidirectional hydrogen bonding between gelator molecules involving oxalamide and carboxamide groups, together with their very low solubility, results in the formation of gel fibres of a very high aspect ratio (d = 10-30 nm, l = 0.6-1.3 μm), resulting in the as-yet unprecedented capacity of gelling commercial fuels. Rheological measurements performed at low concentrations of 10 confirmed the strength of the self-assembled network with the desired thixotropic properties that are advantageous for multiple applications. Instantaneous phase-selective gelation was obtained at room temperature through the addition of the 10 solution to the biphasic mixture of diesel and water in which the carrier solvent was congealed along with the diesel phase. The superior gelling properties and PSG ability of 10 may be used for the development of more efficient marine and surface oil spill recovery and waste water treatment technologies as well as the development of safer fuel storage and transport technologies.

Conversion of waste ship-oil sludge into renewable fuel: Assessment of fuel properties and techno-economic viability of supplementing and substituting commercial fuels

Waste ship-oil sludge (WSOS) is considered as a hazardous waste as it affects the aquatic and dependent ecosystems. However, energy-rich fuels can be obtained upon treating this waste instead of discharging into the sea. Pyrolysis of oily wastes yields a higher proportion of energy-rich fuel when compared to solid wastes. This study provides an insight into the production of different products at various stages of thermal decomposition of completely mixed WSOS and compares its fuel properties such as calorific value, acid content, flash point, distillation, etc. with commercial diesel and aviation fuels. Non-combustible phenol-rich liquids were obtained at a temperature of 220 °C–300 °C (stage – 1) and 300 °C–400 °C (stage – 2). The stage – 2 product contained octa atomic sulphur and the concentration of sulphur in the subsequent stages increased consequently. Stage 3 (475 °C–550 °C) and stage 4 (550 °C–650 °C) products were analysed for commercial fuel properties and compared to conventional diesel and aviation fuels as they contained 45.79% and 56.29% of diesel-equivalent (C13 – C18) hydrocarbons respectively. Stage 3 corresponded well with Grade No.1 diesel fuel according to the ASTM D-975-19 standards and exhibited better properties in comparison with the stage 4 product. An inductive method of techno-economic analysis was carried out. The analysis returned a positive net present value (69,142.49), a high internal return rate (53.78%), and a payback period of 13.52 months, indicating that the sale of pyrolyzed WSOS as commercial fuel will be profitable.

Economic feasibility of catalytic cracking of polymer waste for fuel production

Plastic waste represents a major environmental concern, as it does not degrade in the environment and is constantly discarded. The types of polymers most used in the world are polyethylene and polypropylene, mainly for the production of packaging and, therefore, are the most discarded plastic waste in the environment. Some efforts are being applied to mitigate this situation, such as mechanical recycling, which transforms plastic waste into other products. But polymer cracking processes are promising alternatives, converting waste into lightweight materials that can be turned into commercial fuels. However, to be viable, these processes must consume as little resources as possible and, for this, feasibility experiments must be carried out to prove their application on a large scale and in small transformation units. This work presents a methodology for assembling a low-cost pyrolysis reactor to carry out the cracking of polymeric residues, and experiments were carried out with it, whose results showed the technical and economic viability of the described process, obtaining a rate of conversion of plastic into fuels of up to 96%, so it can be widely applied to reduce impacts caused by plastic disposal.

Catalytic upgrading of bio-oil from halophyte seeds into transportation fuels

Because of socioeconomic considerations, wide-scale production of biofuel necessitates the utilization of nonedible biomass feedstock that does not compete for land and fresh water resources. In this regard, Salicornia bigelovii (SB) is the most investigated halophyte species. The high oil content in SB seeds has sparked mounting research that aims to utilize SB as an industrial crop in the production of bio-oil, particularly in coastal areas where these plants thrive. However, the oil extracted from the pyrolysis of raw SB seeds is largely dominated by oxygenated fatty acids, most notably 9,12-octadecadienoic acid and 9,17-octadecadienal, typical to that of other crops. The pyrolysate bio-oil of the raw SB seeds exhibited a relative yield of oxygenated compounds that decreased from 57.05 % at 200 °C to 9.81 % at 500 °C, and the relative yield of nitrogenated compounds increased from 4.86 % at 200 °C to 21.97 % at 500 °C. To improve the quality of the produced bio-oil, herein we investigated the catalytic hydrodeoxygenation (HDO) of the fragments that were produced from the thermal degradation of SB seeds. A 5 %Ni–CeO2 catalyst was prepared and characterized by a wide array of methods X-ray diffraction, X-ray photoelectron spectroscopy, temperature programmed reduction, scanning electron microscope, Brunauer-Emmett-Teller analysis, and thermogravimetric analyzer. The catalytic run was executed between 200 and 500 °C in a flow reactor. The deployed catalytic methodology displayed a profound HDO capacity. At 400 °C, for instance, the gas chromatography mass spectroscopy (GC–MS) detected loads of paraffin and aromatic compounds exists at appreciable values of 48.0 % and 28.5 %, respectively. With a total relative yield of 43.2 % (at 400 °C), C8–C15 species (i.e., jet fuel fractions) were the most abundant species in the upgraded SB bio-oil. The release of H2, CO, CO2, and CH4 was analyzed qualitatively and quantitatively using gas chromatography thermal conductivity detector and Fourier infrared spectroscopic analysis. When the Ni–CeO2 catalyst was utilized, a complete deoxygenated bio-oil was obtained from SB seeds using the surface-assisted HDO reaction. On the basis of the elemental analysis, the biochar's hydrogen and oxygen contents were found to decrease significantly. Density functional theory computations showed mechanisms for reactions that underpinned the experimentally observed hydrodeoxygenation process. Outcomes presented herein shall be instrumental toward the effective utilization of halophyte in the production of commercial transportation fuels.

High-Degree Oxidative Desulfurization of a Commercial Marine Fuel Using Deep Eutectic Solvents and Their Recycling Process

Escalating environmental concerns have dictated the need to develop innovative methods for efficiently desulfurizing marine fuels (heavy fuel oils). In this work, the oxidative desulfurization method using deep eutectic solvents (DESs) was applied to reduce the sulfur content in a commercially available heavy fuel oil (HFO) below 0.5 wt.%, as current regulations demand. Initially, the S-compounds in the fuel were oxidized using an oxidative mixture of H2O2 with carboxylic acid (either acetic or formic acid). Subsequently, the oxidized S-compounds were extracted from the fuel using a series of environmentally friendly deep eutectic solvents (DESs), the best of which was proven to be a mixture of choline chloride with ethylene glycol at a 1/2 molar ratio. The process was optimized by investigating the effect of several process parameters on the desulfurization efficiency, namely, the H2O2/S molar ratio, the H2O2/acid molar ratio, the acid type, the oxidation temperature and oxidation time, the solvent/fuel mass ratio, the extraction time, and the extraction temperature. A desulfurization efficiency of 75.7% was achieved under the optimized conditions, reducing the S content in the fuel to 0.33 wt.%. Furthermore, different methods to recycle the DESs were investigated, and consecutive desulfurization and solvent regeneration cycles were performed. The most efficient recycling method was determined to be the anti-solvent addition of excess water, which resulted in 89.5% DES purification by causing precipitation of the dissolved solids. After three cycles of desulfurization and regeneration using different recycling routes, it was found that the regeneration degree declines gradually; however, it is more than 79.3% in all cases.

Characterization of particulate matter emissions from internal combustion engines using δ13C values: Impact of engine operation conditions and fuel type on PM10 isotopic composition

Stable carbon isotope ratio of particulate emissions from internal combustion engines (ICEs) is an important characteristic in atmospheric carbonaceous PM source studies. Long-term measurements (2009–2020) of δ13C values of commercial fuels in Lithuania were conducted to evaluate the current isotopic composition of the fuel due to the changing share of renewable energy sources (RES). In this work, we present experimental results on stable carbon isotope ratio (δ13C) in PM10 emitted by different types of ICEs (two-stroke and four-stroke), including on-road transport and non-road mobile machinery. Different driving scenarios were simulated on a test bench (idling, NEDC, different torque, and speed). At idle, the average δ13C(PM10) values of different fuel types were determined: −27.80‰ for gasoline, −28.97‰ for diesel, − 27.89‰ for biofuel-C3, and −16.95‰ for biofuel-C4. Isotopic fractionation during combustion in ICEs depended on fuel type. The magnitude of Δ13C was 3‰ for gasoline, 2‰ for diesel, 1.5‰ for biofuel-C3, and 0.6‰ for biofuel-C4. The δ13C values of ICEs-generated PM10 were found to be dependent on the amount biobased components such as hydrotreated vegetable oil (HVO) to the fuel. However, insubstantial differences were found between the δ13C of PM derived from pure diesel and from an ethanol/diesel blend (E40).