Search Results (86)

It has been proven that the performance of fluid catalytic cracking (FCC), as the most important oil refining process for converting low-value heavy oils into high-value transportation fuels, light olefins, and feedstocks for petrochemicals, depends strongly on the quality of the feedstock. For this reason, characterization of feedstocks and their relationships to FCC performance are issues deserving special attention. This study systematically reviews various publications dealing with the influence of feedstock characteristics on FCC performance, with the aim of identifying the best characteristic descriptors allowing prediction of FCC feedstock cracking capability. These characteristics were obtained by mass spectrometry, SARA analysis, elemental analysis, and various empirical methods. This study also reviews published research dedicated to the catalytic cracking of biomass and waste oils, as well as blends of petroleum-derived feedstocks with sustainable oils, with the aim of searching for quantitative relationships allowing prediction of FCC performance during co-processing. Correlation analysis of the various FCC feed characteristics was carried out, and regression techniques were used to develop correlations predicting the conversion at maximum gasoline yield and that obtained under constant operating conditions. Artificial neural network (ANN) analysis and nonlinear regression techniques were applied to predict FCC conversion from feed characteristics at maximum gasoline yield, with the aim of distinguishing which technique provided the more accurate model. It was found that the correlation developed in this work based on the empirically determined aromatic carbon content according to the n-d-M method and the hydrogen content calculated via the Dhulesia correlation demonstrated highly accurate calculation of conversion at maximum gasoline yield (standard error of 1.3%) compared with that based on the gasoline precursor content determined by mass spectrometry (standard error of 1.5%). Using other data from 88 FCC feedstocks characterized by hydrogen content, saturates, aromatics, and polars contents to develop the ANN model and the nonlinear regression model, it was found that the ANN model demonstrated more accurate prediction of conversion at maximum gasoline yield, with a standard error of 1.4% versus 2.3% for the nonlinear regression model. During the co-processing of petroleum-derived feedstocks with sustainable oils, it was observed that FCC conversion and yields may obey the linear mixing rule or synergism, leading to higher yields of desirable products than those calculated according to the linear mixing rule. The exact reason for this observation has not yet been thoroughly investigated. Full article

Marine microbial-derived docosahexaenoic acid (DHA) has garnered significant attention as a sustainable and health-promoting alternative to fish oil-derived DHA. However, its industrial production from marine heterotrophic microorganisms faces challenges related to high costs and suboptimal oil quality, which hinder its broader application. This review focuses on recent strategies aimed at achieving low-cost and high-quality marine microbial DHA production, emphasizing heterotrophic systems that dominate commercial supply. Key aspects include: Fermentation optimization using waste-derived feedstocks and bioprocess engineering to enhance DHA yields; Critical refining techniques—including degumming, neutralization, decolorization, and deodorization—are analyzed for improving DHA oil purity and quality, with emphasis on process optimization to adapt to the unique biochemical properties of microbial-derived oils. Additionally, strategies for oxidative stabilization, such as antioxidant protection, are discussed to extend the shelf life and preserve the nutritional value of marine microbial DHA oil. By integrating techno-economic and biochemical perspectives, this work outlines a holistic framework to guide the industrial optimization of marine microbial-sourced DHA oil production, addressing cost and quality challenges to facilitate its large-scale application as functional foods and nutraceuticals, thereby reducing reliance on marine resources and advancing sustainable omega-3 production. Full article

Although oily sludge is an industrial waste and difficult to separate, its calorific value can still reach 6000 cal/g, thus possessing significant recycling value. This study compares various types of non-thermal plasma for refining oily sludge. The pre-treatment technology utilized filtration combined with solvent extraction to extract the oil portion from the oily sludge. Subsequently, two types of non-thermal plasma, DC streamer discharge and dielectric plasma discharge, were used to crack and activate the oily sludge under different operating conditions. The fuel compositions and properties of the refined fuel treated by two types of non-thermal plasma were compared. The elemental carbon and oxygen of the oily sludge after treatment in a direct DBD plasma reactor for 8 min were 1.96 wt.% less and 1.38 wt.% higher than those of commercial diesel. The research results indicate that the pre-treatment process can effectively improve the refined fuel properties. After pre-treatment, the calorific value of the primary product from the oily sludge can reach 10,598 cal/g. However, the carbon residue of the oily sludge after pre-treatment remained as high as 5.58 wt.%, which implied that further refining processes are required. The streamer discharge plasma reactor used a tungsten needle tip as a high-voltage electrode, leading to a rather small treated range. Corona discharge and arc formation are prone to being produced during the plasma action. Moreover, the addition of quartz glass beads can form a protruding area on the surface of the oily sludge, generating an increase in the reacting surface of the oily sludge, and hence an enhancement of treatment efficiency, in turn. The direct treatment of DBD plasma can thus have a wider and more uniform operating range of plasma generation and a superior efficiency of plasma reaction. Therefore, a direct DBD type of non-thermal equilibrium plasma reactor is preferable to treat oily sludge among those three types of plasma reactor designs. Additionally, when the plasma voltage is increased, it effectively enhances fuel properties. Full article

The purification of waste cooking oils (WCOs) through clay-based adsorption is an established recycling method, yet the relationship between clay composition and adsorption efficiency remains an area of active research. The aim of the present research work was to assess the performance of Maghnia bentonite in WCO decoloration and to gain information about the specific refining process. Thus, natural bentonite from the Maghnia region (Algeria) was investigated as an adsorbent for WCO refining for biolubricant production. The adsorption efficiency was evaluated under different conditions, achieving up to 70% decolorization at 10 wt% clay after 4 h of treatment. Structural characterization of the bentonite before and after adsorption was conducted using FT-IR spectroscopy, powder X-ray diffraction (XRD), and X-ray fluorescence (XRF) to assess compositional and morphological changes. FT-IR analysis confirmed the adsorption of organic compounds, XRD indicated minor alterations in interlayer spacing, and XRF revealed ion exchange mechanisms, including a reduction in sodium and magnesium and an increase in calcium and potassium. Adsorption kinetics followed a pseudo-second-order model, with desorption effects observed at prolonged contact times. The pHPZC of 8.3 suggested that bentonite adsorption efficiency is enhanced under acidic conditions. The high decoloration capacity of Maghnia bentonite, combined with the availability and the low cost of the material, suggests a possible industrial application of this material for WCO refinement, especially in lubricant production. Full article

This manuscript underscores the significance of converting and reusing lubricating oils for dual purposes as both lubricants and fuels. This approach not only benefits the environment, but also contributes to the circular economy. To this end, this article conducts a review and delves into the applications and re-refining techniques employed to recover lubricating oil from waste lubricating oil (WLO). A global overview of waste oil recycling and political feasibility in the marketplace is presented, highlighting country-specific preferences for reusing such oils. Moreover, this manuscript analyzes several studies that utilize recycled oil as fuel in thermal equipment, including diesel engines. The findings indicate that CO emissions increased incrementally under both low- (from 3.22% to 21.23%) and high-load conditions (from 6.6% to 18.2%) compared to diesel fuel. Another study reveals that 10% and 20% blends of transformer oil and diesel exhibit lower fuel consumption than diesel fuel at high loads. In all the cases examined, WLO demonstrated slightly higher emission levels than marine diesel oil (MDO), yet lower than those observed with heavy fuel oil (HFO). Full article

Currently, the key challenge of the oil-refining industry worldwide is to produce environmentally friendly fuel in large volumes to meet market demand, which is due to strict environmental standards governing the permissible sulfur content in fuel. Natural gas, refinery gas, and coal gas contain acid gases such as hydrogen sulfide and carbon dioxide. These compounds must be removed from the gas stream because of the toxicity of H₂S and to prevent the acid gas-induced corrosion of pipelines and facilities. Hydrogen sulfide is released as a result of various industrial processes, and its removal is critical because this compound can cause corrosion and environmental damage even at low concentrations. Sulfur compounds are also present in natural gas, biofuels and other fuel gases used in power plants. This article proposes new adsorbents of natural and waste origin and presents the results of their testing for the removal of acid gases. This paper also considers methods for the preparation of adsorbents from waste and procedures for the removal of sulfur-containing compounds. Using agricultural, industrial waste to produce activated sorbents not only solves the problem of waste disposal but also reduces the cost of desulfurization, contributing to the creation of sustainable and environmentally friendly technologies. The Review Section comprehensively summarizes current research on hydrogen sulfide removal in gas cleaning processes using agricultural and industrial waste as highly efficient adsorbents. In the Experimental Section, 10 composite materials based on natural raw materials and wastes, as well as 6 commercial adsorbents, were synthesized and tested under laboratory conditions. The choice of materials for the adsorbent production was based on the principles of environmental friendliness, availability, and cost-effectiveness. The developed materials based on modified sludge from water treatment plants of thermal power plants are effective sorbents for the purification of gas emissions from petrochemical enterprises. For industrial use, it is necessary to solve the problems of increasing the economic attractiveness of sorbents from waste, the ability of regeneration, the competitive adsorption of pollutants, the use of indicator sorbents, the optimization of operating conditions, and safe waste disposal. Full article

The appropriate use of food industry by-products such as watermelon seeds could reduce the problem of food waste, following the “zero waste” concept. Research in recent years suggests that these unused waste products could be a source of nutrients and bioactive compounds. Accordingly, the present study aimed to evaluate the nutritional potential and selected quality parameters of watermelon seed oils. Four commercial oils (three unrefined cold-pressed and one refined pressed) and one self-extracted oil were considered. The oils were analyzed over three months of storage after opening/extraction to determine their fatty acid (FA) composition and distribution, hydrolytic and oxidative stability, and selected health indices. Linoleic acid was the predominant FA, ranging from 52.9% (refined oil) to 62.2% (self-extracted oil). Refined oil demonstrated superior oxidative stability, with the lowest acid value (AV) and peroxide value (PV) throughout the storage period, adhering to the Codex Alimentarius standards. Unrefined oils, particularly WO₃, showed significantly higher AVs and PVs after storage, indicating greater susceptibility to hydrolytic and oxidative changes. Health indices were favorable for all oils, with self-extracted oil exhibiting the highest health-promoting index (7.07) and hypocholesterolemic/hypercholesterolemic ratio (7.18). Oxidative stability showed that self-extracted oil had significantly higher stability (76.6 min) than other tested oils, despite having the highest PUFA content. In turn, refinement has a significant effect on the AVs and PVs and the oxidative stability of oil, achieving the lowest PUFA level (53.61%). These results emphasize the potential of watermelon seed oil as a health-promoting product and emphasize the role of production and storage conditions in maintaining its quality. Full article

As environmental awareness grows, hydrodesulfurization (HDS) catalysts have become crucial in petroleum refining, yet their use results in oil-laden waste, poses environmental risks, and complicates subsequent treatment. Efficient oil removal is thus critical for processing spent catalysts. This study systematically compares three de-oiling methods, extraction, chemical thermal washing, and pyrolysis, to identify the optimal de-oiling method. In the experiments, extraction achieves a 94.12% oil removal rate at a liquid-to-solid ratio of 10 mL/g, a temperature of 45 °C, and a time of 60 min, maintaining around 90% efficiency after five cycles of solvent recovery. Chemical thermal washing achieves an oil removal rate of 96.26% after 4 h at 90 °C, with 0.15 wt.% SDS, 3.0 wt.% NaOH, and a liquid-to-solid ratio of 10 mL/g. The heavy oil emulsion is then decomposed with 4% CuO and 5% H₂O₂. The pyrolysis method removes 96.19% of oil at 600 °C in 60 min. While the extraction and chemical thermal washing methods are effective, they produce wastewater, raising environmental concerns. In contrast, the pyrolysis method is more environmentally friendly. SEM, EDS, and FT-IR analyses show that after oil removal, the metal structures on the alumina support of the spent HDS catalyst are clearly exposed, facilitating the subsequent recovery of valuable metals. Full article

The aim of the work was to study the effect of additive concentration on changes in the adhesive and cohesive strength of bitumen. To evaluate the effectiveness of modifiers in the composition of binary and triple bitumen systems in relation to mineral fillers of two grades, the method of determination of the adhesive efficiency and thermodynamic calculations of adhesion and cohesion work were used. The following compounds were used as additives: AS-2 synthesized from the oil refining waste and AG-4I (waste sealing liquid). Adhesion–cohesion processes in modified bitumen systems are limited by the wetting effect of crushed stone and the intensity of intermolecular forces in the condensed phase of the binder. In the binary compositions, the addition of modifiers into bitumen significantly improves the cohesive strength and adhesive efficiency in relation to crushed stone. The introduction of AS-2 into bitumen compositions with AG-4I increases adhesion efficiency and thermodynamic work of adhesion in relation to the filler surface. The adhesion efficiency and thermodynamic work of adhesion in the “bitumen-AG-4I-AS-2” system reach their maximum at C_AG-4I = 3.0 g/dm³ and C_AS-2 = 1.5 g/dm³. In these concentration modes, the composition ensures maximum increase in adhesion efficiency (A_KS = 65.18%; A_KA = 48.11%) and the greatest increase in thermodynamic work of adhesion (W_A(KS) = 15.79 mN/m; W_A(KA) = 14.13 mN/m). Full article

The widespread use of polystyrene has brought great convenience to people’s lives, but inappropriate recycling practices can also have a significant negative impact on the environment and public health. In this work, waste polystyrene was refined using maleic acid anhydride to produce flow improvers. The effect of the modified polystyrene perception of viscosity reduction and pour point depression of Henan oil was evaluated. The results show that modified polystyrene reduces the viscosity of Henan oil by 96.5% at most and depresses the pour point by 6.1 °C at most. Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (¹HH NMR) were used to investigate the modified polystyrene. The mechanism of modified polystyrene that improves the fluidity of heavy oil was proposed and analyzed through the study of wax crystal morphology (at 20 °C below the pour point). Full article

In the production of refined sunflower oil, waxes are removed during the winterization stage, and wax crystals are separated through filtration assisted by filtration aids. Commonly used filtration aids in oil refining include perlite and diatomaceous earth. After winterization, a significant amount of filter cake remains as a by-product and is treated as waste. Today, natural cellulose fibers are being promoted as filtration aids. Their advantages are numerous, both in the production process and from an environmental perspective. However, their only disadvantage is their higher cost. Therefore, in this study, 57 filtration cycles during the industrial sunflower oil winterization step using cellulose-based filtration aids were monitored. Different process parameters, including the pressure differential on the filter, the flow rate of filtered oil, constant pressure period, the quantity of filtered oil, filtration time, the quantity of pre-coating and dosing filtration aids, the volume of filtered oil, the concentration of dosing filtration aid, as well as the mass of separated waxes, were observed. Additionally, artificial neural networks were applied to predict process parameters, optimize the process, and, above all, determine the dosage of filtration aids, which will make the process more economical. The optimal filtration process is performed at a pressure differential of 3.3 bar, lasting a total of 39 h, with 32 h at constant pressure, resulting in 322,503 kg of filtered oil and 90.41 kg of waxes. The optimal quantity of cellulose-based filtration aids employed for pre-coat was 80 kg, and for dosing, 375 kg, with an optimal concentration of 0.12% w/w. Full article

Although lignin is a plentiful biomass resource, it continually exists as an underutilized component of biomass material. Elemental sulfur is another abundant yet underutilized commodity produced as a by-product resulting from the refining of fossil fuels. The current study presents a strategy for preparing five durable composites via a simple one-pot synthesis involving the reaction of lignin oil and elemental sulfur. These lignin oil–sulfur composites LOS_x@T (where x = wt. % sulfur, ranging from 80 to 90, and T represents the reaction temperature in °C) were prepared via the reaction of elemental sulfur and lignin oil (LO) with elemental sulfur. The resulting composites could be remelted and reshaped several times without the loss of mechanical strength. Mechanical, thermal, and morphological studies showed that LOS_x@T possesses properties competitive with some mechanical properties of commercial building materials, exhibiting favorable compressive strengths (22.1–35.9 MPa) and flexural strengths (5.7–6.5 MPa) exceeding the values required for many construction applications of ordinary Portland cement (OPC) and brick formulations. While varying the amount of organic material did not result in a notable difference in mechanical strength, increasing the reaction temperature from 230 to 300 °C resulted in a significant increase in compressive strength. The results reported herein reveal potential applications of both lignin and waste sulfur during the ongoing effort toward developing recyclable and sustainable building materials. Full article

Organic solid waste treatment is crucial for enhancing environmental sustainability, promoting economic growth, and improving public health. Following our previous organic solid waste upgrading technique, a further two-step pilot-scale run, using sugarcane bagasse as the feedstock, has been successfully conducted with long-term stability. Firstly, the sugarcane bagasse was treated under mild conditions (400 °C and 1 bar of CH₄), and this catalytic Methanolysis treatment resulted in a bio-oil with a yield of 60.5 wt.%. Following that, it was subjected to a catalytic Methano-Refining process (400 °C and 50 bar of CH₄) to achieve high-quality renewable fuel with a liquid yield of 95.0 wt.%. Additionally, this renewable fuel can be regarded as an ideal diesel component with a high cetane number, high heating values, a low freezing point, low density and viscosity, and low oxygen, nitrogen, and sulfur contents. The successful pilot-scale catalytic upgrading of sugarcane bagasse further verified the effectiveness of this methane-assisted organic solid waste upgrading technique and confirmed the high flexibility of this innovative technology for processing a wide spectrum of agricultural and forestry residues. This study will shed light on the further valorization of organic solid waste and other carbonaceous materials. Full article

Removal of polar impurities, such as phospholipids, free fatty acids (FFA), and peroxides, can be challenging during the refining of crude canola oil. Current conventional refining methods are energy-intensive (e.g., hot water washes) and can generate significant waste (e.g., wastewater effluent) and neutral oil loss. This study investigated the joint use of nano-adsorbents and electrostatic field (E-field) treatment as a potential and sustainable alternative in removing these impurities during the oil refining process. Specifically, aluminum oxide (Al₂O₃) nanoparticles were employed to neutralize FFAs, achieving a 62.4% reduction in acid value while preserving the fatty acid profile of the oil. After refining, E-field treatment was successful in removing the spent nano-adsorbent from solution (up to 72.3% by weight), demonstrating enhanced efficiency compared to conventional methods (e.g., gravitational settling, filtration, and centrifugation). The neutral oil loss using Al₂O₃ nano-adsorbents was also comparable to conventional refining methods, with a 4.38% (by weight) loss. After E-field treatment, the Al₂O₃ nano-adsorbent was then calcined to assess reusability. The Al₂O₃ nano-adsorbent was effectively recycled for three refining cycles. the methods do not use of large amounts of water and generate minimal waste byproducts (e.g., effluent). Nonetheless, while the nano-adsorbents demonstrated promising results in FFA removal, they were less effective in eliminating peroxides and pigments. E-field techniques were also effective in removing spent nano-adsorbent; although, optimization of E-field parameters could further improve its binding capacity. Finally, future studies could potentially focus on the physicochemical modifications of the nano-adsorbent material to enhance their refining capacity and reusability. Overall, this study presents a sustainable alternative or addition to conventional refining methods and lays the groundwork for future research. Full article

Typically, citrus waste is composted on land by producers or used as livestock feed. However, the biorefinery approach offers a sustainable and economically viable solution for managing and valorizing these agricultural residues. This review examines research from the period 2014 to 2024. Citrus waste can be utilized initially by extracting the present phytochemicals and subsequently by producing value-added products using it as a raw material. The phytochemicals reported as extracted include essential oils (primarily limonene), pectin, polyphenolic components, micro- and nano-cellulose, proteins, and enzymes, among others. The components produced from the waste include bioethanol, biogas, volatile acids, biodiesel, microbial enzymes, and levulinic acid, among others. The review indicates that citrus waste has technical, economic, and environmental potential for utilization at the laboratory scale and, in some cases, at the pilot scale. However, research on refining pathways, optimization, and scalability must continue to be an active field of investigation. Full article