Brown Grease Research Articles

Assessing the Performance of Recycled Asphalt Mixtures Using Rejuvenators

After serving their intended purpose, traditional asphalt pavements are destroyed and dumped across the neighboring fields in Pakistan, affecting the natural environment. Only 15% of the old asphalt material has been recycled on the Motorway (M-2) near Shekhupura. Thus, the current study was intended to increase the amount of recycled asphalt, utilizing waste engine oil (WEO), waste cooking oil (WCO), and waste brown grease (WBG) as rejuvenators. Therefore, the asphalt mixture containing 50% recycled materials, rejuvenated with 5%, 10%, 15%, 20%, and 25% WEO, WCO, and WBG, respectively, were investigated. The asphalt samples for Marshall Stability, indirect tensile strength, and rut resistance were prepared and tested as per ASTM D1559, ASTM D979, and ASTMD8360, respectively. The results showed that WEO, WCO, and WBG of 15% and 20%, respectively, are best for equating the properties of recycled binder to those of neat binder, except for ductility characteristics. The results also demonstrated that, in comparison to the traditional asphalt mixture, asphalt mixes with 50% recycled materials performed significantly better in terms of Marshall stability at 15% utilization of WEO, WCO, and WBG, respectively. Additionally, it is established that recycled asphalt mixture, at WEO of 15%, displayed equivalent rut resistance to virgin asphalt mixture. The results of this study will help recycle old asphalt materials for practical engineering purposes, lowering the dependence on natural resources and benefiting the environment.

Anaerobic biodegradation of brown grease and its potential as a source of renewable energy

The purpose of the study was twofold. The first was to study the anaerobic digestibility and the biochemical methane potential (BMP) of brown grease (BG)–fats and oils collected from restaurants and similar food production facilities. The second objective was to investigate the effects of adding dry, food waste derived hydrochar to enhance the digestion process, specifically as a possible in situ agent to improve biogas quality. The BMP tests involved various BG loadings between 3 and 30 g BG/L. The results indicate that BG is highly digestible under anaerobic conditions with 354 mL CH4/g COD equivalent of BG at 1 atm and 35°C testing conditions, which translates into 28 million gasoline gallon equivalent (GGE) potential energy that could be recovered by anaerobically digesting or co-digesting BG. The particular hydrochar investigated in this study did not show any potential to increase biogas CH4 content.

Life‐cycle analysis of sustainable aviation fuel production through catalytic hydrothermolysis

AbstractCatalytic hydrothermolysis (CH) is a sustainable aviation fuel (SAF) pathway that has been recently approved for use in aircraft fuel production. In alignment with broader sustainable aviation goals, SAF production through CH requires a quantitative assessment of carbon intensity (CI) impacts. In this study, a current‐day life‐cycle analysis (LCA) was performed on SAF produced via CH to determine the CI. Various oily feedstocks were considered, including vegetable oils (soybean, carinata, camelina and canola) and low‐burden oils and greases (corn oil, yellow grease and brown grease). Life‐cycle inventory data were collected on all processes within the CH LCA boundary: feedstock cultivation and/or collection, preprocessing, hydrothermal cleanup and CH, biocrude refining, fuel transportation and end use through combustion. Baseline results show that the CH‐produced SAF can be generated with CI reductions ranging from 48 to 82% compared with conventional jet fuel. Modest improvements to CI can be achieved through incremental changes to the brown grease CH process, such as relaxing the dewatering specification and implementing renewable natural gas and electricity, which could decrease the CI from 22.9 to 7.9 g CO2e/MJ. Total CH fuel production potential was also assessed on the basis of current or near‐future feedstock availability and CI. The total biofuel production potential of CH (SAF and renewable fuel co‐products) in the US sums to approximately 3487 million gallons per year, with 97% of these volumes having a CI below 50% of that for petroleum jet fuel. The study shows that from an LCA perspective, CH offers a viable SAF pathway that is comparable with existing SAF pathways like hydroprocessed esters and fatty acids.

Antibacterial Agents from Waste Grease: Arylation of Brown Grease Fatty Acids with Beechwood Creosote and Derivatization

Antibacterial Agents from Waste Grease: Arylation of Brown Grease Fatty Acids with Beechwood Creosote and Derivatization

Composites produced from waste plastic with agricultural and energy sector by‐products

AbstractA three‐stage route to chemically upcycle post‐consumer poly(ethylene terephthalate) (PET) to produce high compressive strength composites is reported. This procedure involves initial glycolysis with diethylene glycol to produce a mixture (GPET) comprising oligomers of 2–7 terephthalate units followed by trans/esterification of GPET with fatty acid chains supplied by brown grease, an agricultural by‐product of animal fat of relatively low nutritional or fuel value. This process yields PGB comprising a mixture of mono‐terephthalate ester derivatives. The olefin units provided by unsaturated fatty acid chains in brown grease were crosslinked by an inverse vulcanization reaction with elemental sulfur to give composites GBSx (x = wt% S, varied from 80%–90%). The compressive strengths of GBS80 (27.5 ± 2.6 MPa) and GBS90 (19.2 ± 0.8 MPa) exceed the compressive strength required of ordinary Portland cement (17 MPa) for its use in residential building foundations. The current route represents a way to repurpose waste plastic, energy sector by‐product sulfur, and agricultural by‐product brown grease to give high strength composites with mechanical properties suggesting their possible use to replace less sustainably sourced legacy structural materials.

Evaluation of Animal Fats and Vegetable Oils as Comonomers in Polymer Composite Synthesis: Effects of Plant/Animal Sources and Comonomer Composition on Composite Properties

AbstractRancid animal fats unsuitable for human or animal food production represent low‐value and abundant, yet underexploited organic chemical precursors. The current work describes a strategy to synthesize high sulfur‐content materials (HSMs) that directly utilizes a blend of partially hydrolyzed chicken fat and plant oils as the organic comonomers, following up on analogous reactions using brown grease in place of chicken fat. The reaction of sulfur and chicken fat with either canola or sunflower oil yielded crosslinked polymer composites CFSx or GFSx, respectively (x = wt% sulfur, varied from 85%–90%). The composites exhibited compressive strengths of 24.7–31.7 MPa, and flexural strengths of 4.1–5.7 MPa, exceeding the value of established construction materials like ordinary Portland cement (compressive strength ≥17 MPa required for residential building, flexural strength 2–5 MPa). The composites also exhibited thermal stability up to 215–224 °C. The simple single‐step protocol described herein represents a way to upcycle an affordable and previously unexploited animal fat resource to form structural composites via the atom economical inverse vulcanization mechanism.

Thermal and Mechanical Properties of Recyclable Composites Prepared from Bio-Olefins and Industrial Waste

Ordinary Portland Cement (OPC) production consumes tremendous amounts of fresh water and energy and releases vast quantities of CO2 into the atmosphere. Not only would an alternative to OPC whose production requires no water, releases little CO2, and consumes less energy represent a transformative advance in the pursuit of industrial decarbonization, but the greater availability of safe drinking water would lead to significantly improved public health, particularly among vulnerable populations most at risk from contaminated water supply. For any OPC alternative to be adopted on any meaningful scale, however, its structural capabilities must meet or exceed those of OPC. An inverse vulcanization of brown grease, sunflower oil, and elemental sulfur (5:5:90 weight ratio) was successfully modified to afford the high-sulfur-content material SunBG90 in quantities > 1 kg, as was necessary for standardized ASTM and ISO testing. Water absorption (ASTM C140) and thermal conductivity (ISO 8302) values for SunBG90 (<1 wt% and 0.126 W·m−1·K−1, respectively) were 84% and 94% lower than those for OPC, respectively, suggesting that SunBG90 would be more resistant against freeze-thaw and thermal stress damage than OPC. Consequently, not only does SunBG90 represent a more environmentally friendly material than OPC, but its superior thermomechanical properties suggest that it could be a more environmentally robust material on its own merits, particularly for outdoor structural applications involving significant exposure to water and seasonal or day/night temperature swings.

Toward Efficient Continuous Production of Biodiesel from Brown Grease

An increase in energy consumption and the extended use of nonrenewable fossil fuels raises the need to develop alternative fuels as an energy supply that can protect the environment from unwanted emissions of pollutants. One alternative renewable fuel is biodiesel. Currently, most biodiesel feed sources are edible oils, but using them leads to the dilution of global food sources. The present study aims to find an effective method of biodiesel production using food industry fatty wastes called brown grease (BG). BG contains fats, mainly linoleic and oleic free fatty acids (FFAs), that can serve as raw materials for biodiesel production using esterification reactions. The esterification and transesterification reactions for biodiesel production were studied using commercial FFAs, commercial glyceryl trilinoleate (trilinolein), soybean oil, and BG. The reactions were carried out under ultrasonic activation using BF3 and AlCl3 Lewis acids as catalysts in both free and immobilized forms when immobilization was performed in silica matrices using the sol-gel synthesis route. Biodiesel production was examined in batch and continuous flow reactors. The BF3 catalyst was more efficient at the initial stages of the continuous operation, reaching a maximum conversion of 90%, with a gradual decrease in efficiency after 15 h of the process. The AlCl3 catalyst showed better stability, reaching maximum yields of 97% and maintaining efficiency until the end of the experiment. The proposed method offers an efficient and easy way to produce biodiesel from a variety of lipids sources, including fatty wastes (BG).

Application of Quaternary Ammonium-Based Deep Eutectic Solvents as Catalysts for the Glycerolysis of Free Fatty Acids

Nonedible waste sourced lipids such as fatty acid distillates, brown grease, and animal tallow, among many others, are excellent alternatives for expanding the feedstock inventory for biodiesel synthesis. A quaternary ammonium-based deep eutectic solvents (DESs) was used as a catalyst in the glycerolysis of free fatty acids (FFAs) in this study. Reaction optimization was carried out with oleic acid as the model molecule, followed by an in-depth examination of the reaction mechanism. Optimum conditions such as 130 °C and 10 wt % catalyst dosage with 10 min of reaction time gave an equilibrium conversion of 94%. The catalyst was found to remain in the glycerol phase allowing its reuse. Palm fatty acid distillate, brown grease, and crude glycerol were utilized for testing the novel DES at optimum conditions. FFA conversion was found to be 94% for both palm fatty acid distillate and brown grease. In the case of crude glycerol, FFA conversion decreased proportionally to the impurity level. Water was responsible for restricting equilibrium conversion and decreasing catalyst recyclability, necessitating further research into effective removal during the reaction. Aggressive nitrogen purging to remove water during the reaction pushed the reaction toward near-completion in 60 min. The catalyst reusability study showed a drop in equilibrium conversion to 62.5% at the end of the 5th cycle, even when water was removed.

Desulfurization of biodiesel produced from waste fats, oils and grease using β-cyclodextrin

Making biodiesel from the fat, oil and grease in wastewater is attractive for sustainable biofuel production, waste management and public health. Sulfur reduction is a critical problem in biofuel production from low grade feedstocks containing high levels of sulfur contamination. Traditional desulfurization methods face challenges due to the financial and environmental costs of required catalysts, reagents or energy.This paper presents a new desulfurization method applied to biodiesel that uses β-cyclodextrin as the adsorbent. Biodiesel was produced from brown grease decanted from the FOG delivered to a local wastewater treatment plant. The equilibrium and kinetic behavior of the adsorption process were quantified with experimental measurements using the produced biodiesel and commercially available β-CD. A convection/diffusion model was then developed to simulate the adsorption process in a fixed bed adsorber. A 3-column design is presented based on the model results and compared with a sulfur reduction system based on vacuum distillation.The β-CD system operates at ambient temperature and pressure, whereas the vacuum distillation system operates at less than 0.01 Atm and near 200 C. The initial cost of the β-CD system is expected to be less than half the cost of the distillation system, but the operating costs may be similar. The β-CD system does not require the addition of hydrogen as in hydrodesulfurization but does require regeneration and periodic replacement of β-CD. Process intensification strategies such as polymerizing the β-CD or using more innovative process designs than fixed bed adsorbers may further increase the advantages of a β-CD based desulfurization system.

Yellow and brown grease—characteristics of compression-ignition engine

This papers presents the results of analysis done on a compression-ignition engine supplied with methyl ester of rapeseed oil (Yellow Grease), methyl ester of goose fat (Brown Grease) and pure diesel. The analysis included the engine characteristics, emissions and fuel consumption. Results also include chromatographic analysis for all of the three fuels. Additional evaluation was done on a vehicle idling and under load.

The Research on Characteristics of CI Engine Supplied with Biodiesels from Brown and Yellow Grease

The effect of three kinds of fuels used to supply a diesel engine on its characteristics, fuel consumption, and emissions was studied. The fuels comprised pure diesel, a blend of diesel with 6% of methyl ester of yellow grease in the form of rapeseed oil, and a blend of diesel with methyl ester of brown grease in the form of goose fat. The chromatographic analysis was conducted for these fuels, and the results are presented. Two tests, comprising measurement of fuel consumption and engine emissions, were conducted on a vehicle with a diesel engine operating under zero load and under full load. The engine’s characteristics, including both power and torque versus speed, were determined under full engine load. The results of these tests are presented in this paper. The results indicated that the use of different methyl ester-based biodiesel blends with the same content of diesel to supply the diesel engine resulted in different fuel consumption and emissions of the engine not only in comparison to the supply of pure diesel but between biodiesels analyzed.

Biosolids-based catalyst for oxidative desulphurization of drop-in fuels derived from waste fats

In this work, the catalytic performance of a biosolids-based catalyst was tested in the oxidative desulphurization process of a model fuel solution containing benzothiophene ([S] of 500 ppm), as well as sulphur-rich products from a two-step thermal conversion process of brown grease to renewable hydrocarbons using biosolids as a water replacement during the hydrolysis step. The catalytic results of the biosolids-based material were compared with a classical Fenton-like reagent and a non-catalytic system. Biosolids-based catalyst outperformed the other systems at low temperature with a full desulphurization of benzothiophene solution achieved at 60 °C after 3 h and a good recyclability after four catalytic runs at 80 °C for 3 h. The desulphurization was less effective for hydrolysed fatty acids and crude pyrolysis oil derived from the conversion of brown grease to renewable hydrocarbons, which was due to the composition of the sulphur containing compounds, but still reached 87.7 ± 3.0 % and 74.7 ± 9.5 %, respectively.

High strength composites from low-value animal coproducts and industrial waste sulfur.

Herein we report high strength composites prepared by reaction of sulfur, plant oils (either canola oil or sunflower oil) and brown grease. Brown grease is a high-volume, low value animal fat rendering coproduct that represents one of the most underutilized products of agricultural animal processing. Chemically, brown grease is primarily comprised of triglycerides and fatty acids. The inverse vulcanization of the unsaturated units in triglycerides/fatty acids upon their reaction with sulfur yields CanBGx or SunBGx (x = wt% sulfur, varied from 85–90%). These composites were characterized by infrared spectroscopy, dynamic mechanical analysis (DMA), mechanical test stand analysis, elemental analysis, and powder X-ray diffraction. CanBGx and SunBGx composites exhibit impressive compressive strengths (28.7–35.9 MPa) when compared to other materials such as Portland cement, for which a compressive strength of ≥17 MPa is required for residential building. Stress–strain analysis revealed high flexural strengths of 6.5–8.5 MPa for CanBGx and SunBGx composites as well, again exceeding the range of ∼2–5 MPa for ordinary Portland cements. The thermal properties of the composites were assessed by thermogravimetric analysis, revealing decomposition temperatures ranging from 223–226 °C, and by differential scanning calorimetry. These composites represent a promising new application for low value animal coproducts having limited value to be used as organic crosslinkers in the atom-efficient inverse vulcanization process to yield high sulfur-content materials that have impressive mechanical properties.

Shortcut design of sulfur reduction distillation system using pseudo-component description of biodiesel and the sulfur contaminants

A critical factor in environmental degradation is the coupled problem of world population growth and waste management, including wastewater management. Making biodiesel from the FOG (fat, oil and grease) in the wastewater system is an attractive path for sustainable biofuel production, waste management and public health. High sulfur content is the biggest challenge in biodiesel produced with the brown grease extracted from FOG.The purpose of this paper is to present a new method to design the sulfur reduction process based on a pseudo-component approach that greatly reduces the effort required to characterize the complex mixture of methyl esters and sulfur containing contaminants. To demonstrate this method, biodiesel was produced from decanted brown grease using several combinations of acid and base catalysts in a two-step esterification/ transesterification process. Vacuum batch distillation was applied to the crude biodiesel product to generate volatility and sulfur distribution data. An easily applied vapor/liquid equilibrium model was then developed using 7 pseudo-components, each with an assigned sulfur content. A principal result is that the pseudo-component model very accurately simulated the batch distillation data. These pseudo-components were then used in the ASPEN software to design a continuous distillation system for a FOG to biodiesel system being installed at a wastewater treatment plant. The second principal result is the ASPEN based design predicts a biodiesel product containing sulfur lower than 10 ppm, satisfying sulfur requirements worldwide. In conclusion, the pseudo-component design method is a versatile and easily applied approach to design sulfur reduction processes.

Desulphurization of drop-in fuel produced through lipid pyrolysis using brown grease and biosolids feedstocks

Biosolids can be incorporated as a water replacement into a two-stage thermal process for biofuel production from brown greases, significantly reducing the overall environmental impact of the process. Unfortunately, the use of biosolids resulted in an appreciable amount of sulphur in the pyrolytic oils produced in the final stage of the process. Here, we first evaluated the relationship between the sulphur content of fatty acids pyrolysis liquid products and pyrolytic conditions. Afterwards, we evaluated the sulphur removal efficiency of several approaches such as distillation, extraction and adsorption. Through a combination of distillation and liquid-liquid extraction, we achieved a desulphurization of up to 95% reaching a final sulphur concentration of 15 ± 4 ppm.

Techno-economic analysis of catalytic hydrothermolysis pathway for jet fuel production

The aviation industry is moving towards increasing the use of renewable fuels to reduce its environmental impact and find alternative supply chains for aviation fuel. Analyzing the technical and economic viability of sustainable aviation fuel (SAF) conversion pathways provides critical understanding and new insight toward long-term sustainability and commercialization of SAF. This study reviews the catalytic hydrothermolysis (CH) pathway for sustainable aviation fuel production and conducted a detailed techno-economic analysis to determine the economic viability of SAF production from four selected feedstocks - carinata oil, soybean oil, yellow grease, and brown grease. Economic analyses were performed for ‘nth plant’ (mature technology) to assess process costs and sensitivity on minimum selling price (MSP) of SAF. Without incentives, the MSP of SAF produced from soybean oil, carinata oil, yellow grease, and brown grease are $1.50/L, $1.32/L, $1.19/L for and $1.00/L respectively. Regardless of feedstock, the MSP is shown to be more sensitive to the yield of SAF and feedstock cost, than to capital and supplementary costs. Based on the analysis, the CH process is a promising technology to convert renewable oils to SAF, however the projected MSP requires incentives to achieve parity with petroleum jet fuel.

Mechanistic Investigation of the Pyrolysis of Brown Grease

The conversion of brown grease using pyrolysis reactions represents a very promising option for the production of renewable fuels and chemicals. Brown grease forms a mixture of alkanes, alkenes, and ketones at a temperature above 300°C at atmospheric pressure. This work is a computational study of the detailed reaction mechanisms of brown grease pyrolysis using DFT methodology. Prior experimental investigations confirmed product formation consistent with a set of radical reactions with CO2 elimination, as well as ketone by product formation, CO forming reactions, and formation of alcohols and aldehydes as minor byproducts. In this work, computational quantum chemistry was used to explore these reactions in greater detail. Particularly, a nonradical pathway formed ketone byproducts via the ketene, which we refer to as Pathways A1 and A2. Radical formation by thermal decomposition of unsaturated fatty acids initiates a set of reactions which eliminate CO2, regenerating alkyl radicals leading to hydrocarbon products (Pathway B). A third pathway (Pathway C) is an alternative set of radical reactions, resulting in decarbonylation and formation of minor byproducts. The results of the calculations are in good agreement with recent experimental studies.

Brown grease pyrolysis under pressure: Extending the range of reaction conditions and hydrocarbon product distributions

Pyrolysis of brown grease to hydrocarbon products was performed in a pressure reactor. Compared to our previous work at atmospheric pressure, higher reaction temperatures could be achieved. These resulted in shorter reaction times, reduced formation of undesirable ketone byproducts, and a higher percentage of the most valuable light hydrocarbon products. Higher temperatures did, however, increase the percentage of gas products at the expense of liquid products. The major liquid products are alkanes ranging from heptane to heptadecane, with smaller amounts of cycloalkanes, and in some cases, aromatic compounds.

Production of Biodiesel from Brown Grease

Among the renewable energy sources is biodiesel. This fuel is usually produced by catalytic transesterification of vegetable oils and animal fats under heating and pressure. Brown grease is a mixture of oils, fats, solids and detergents from food industry wastes that is captured in grease traps. Brown grease is classified as waste and must be treated and disposed of appropriately. It contains oils and fats that can be converted into biodiesel. However, the high concentration of free fatty acids in brown grease does not enable the use of conventional biodiesel production schemes. This study proposes a new scheme for biodiesel production from brown grease. In addition, conditions for the effective separation of a fat phase from brown grease were tested, and the composition of a fatty phase was determined for several grease traps. Esterification and transesterification of brown grease lipids were carried out with methanol, where the Lewis acids BF3 and AlCl3 were used as catalysts and the reaction was activated by ultrasound. The results show that biodiesel can be obtained from brown grease by esterification and transesterification within several minutes under ultrasonic activation at room temperature. These results open prospects for the development of efficient, low-cost and environmentally friendly biodiesel production.