Brown Grease Research Articles

Biogas production from brown grease using a pilot-scale high-rate anaerobic digester

Food wastes are typically disposed of in landfills for convenience and economic reasons. However, landfilling food wastes increases the organic content of leachate and the risk of soil contamination. A sound alternative for managing food wastes is anaerobic digestion, which reduces organic pollution and produces biogas for energy recovery. In this study, anaerobic digestion of a common food waste, brown grease, was investigated using a pilot-scale, high-rate, completely-mixed digester (5.8 m3). The digestibility, biogas production and the impact of blending of liquid waste streams from a nearby pulp and paper mill were assessed. The 343-day evaluation was divided into 5 intensive evaluation stages. The organic removal efficiency was found to be 58 ± 9% in terms of COD and 55 ± 8% in terms of VS at a hydraulic retention time (HRT) of 11.6 ± 3.8 days. The removal was comparable to those found in organic solid digesters (45–60%), but at a much shorter HRT. Methane yield was estimated to be 0.40–0.77 m3-CH4@STP kg-VSremoved−1, higher than the typical range of other food wastes (0.11–0.42 m3-CH4@STP kg-VSremoved−1), with a mean methane content of 75% and <200 ppm of hydrogen sulfide in the biogas. The blending of selected liquid wastes from a paper mill at 10 vol% of brown grease slurry did not cause significant reduction in digester performance. Using a pseudo-first-order rate law, the observed degradation constant was estimated to be 0.10–0.19 d−1 compared to 0.03–0.40 d−1 for other organic solids. These results demonstrate that brown grease is a readily digestible substrate that has excellent potential for energy recovery through anaerobic digestion.

Two-stage thermal conversion of inedible lipid feedstocks to renewable chemicals and fuels

The aim of this work was to study the conversion of inedible, low cost lipid feedstocks to renewable hydrocarbons using a two stage thermal hydrolysis-pyrolysis method. Beef tallow, yellow grease, brown grease and cold pressed camelina oil were first hydrolyzed and the fatty acids produced were recovered and pyrolyzed in batch reactors. The pyrolysis products were identified and quantified using gas chromatography and mass spectrometry. The pyrolysis product yields were similar for all the feedstock used with the organic liquid fraction (OLF) accounting for 76-80% of the product. The OLF consisted predominantly of n-alkanes. Approximately 30% OLF constituted a gasoline-equivalent fraction and 50% a diesel fraction. Other fuel property test showed that the OLF met the specifications set out by the Canadian general standards board. This research demonstrated a novel two-stage thermal hydrolysis-pyrolysis conversion method for producing OLF from inedible and low-value lipids.

Efficient conversion of brown grease produced by municipal wastewater treatment plant into biofuel using aluminium chloride hexahydrate under very mild conditions

Wastes produced by oil/water separation at the wastewater treatment plant of Bari West (Southern Italy) were taken, characterized and converted. About 12% of this material was composed of greases, mainly made of free fatty acids (50%) and soaps (34%), and was easily separable by the aqueous phase through a hot centrifugation. After chemical activation of this fatty fraction, a direct esterification was carried out under very mild conditions (320K and atmospheric pressure), converting more than 90% of the original free fatty acids into the respective methyl esters in less than 4h, by using AlCl3·6H2O. The activation energy correlated to the use of this catalyst was also calculated (Eaest=43.9kJmol(-1)). The very low cost of the biodiesel produced (0.45€L(-1)) and the associated relevant specific energy (5.02MJ kgFAMEs(-1)) make such a process a really sustainable and effective example of valorization of a waste.

Microwave Assisted Biodiesel Production from Trap Grease

Methyl and ethyl esters were prepared from lauric acid under conventional heating and microwave irradiation to determine the best fatty acid esterification conditions. These conditions were then applied in the conversion of trap grease (brown grease) to biodiesel. The trap grease is a potential feedstock for biodiesel production, due to its low cost and easy esterification. In this paper, trap grease catalytic esterification with methanol was performed under conventional heating and microwave irradiation. It was possible to obtain high conversions with conventional heating, but under microwave heating, the esterification reaction equilibrium was attained much faster. The trap grease biodiesel obtained from microwave assisted reactions showed a high conversion (96%) even at mild reaction conditions (trap grease:methanol molar ratio 1:6, 1.0% H2SO4, 393 K, 10 minutes). While these initial experiments were performed in a small-scale laboratory unit, the procedure could be easily scaled-up to a commercial continuous process.

The Enzymatic Conversion of Brown Grease to Biodiesel in a Solvent-free Medium

Brown grease was used in this study on the conversion to biodiesel fatty acid methyl ester (FAME) by a two-stage reaction comprising esterification and transesterification using Novozym 435 in a solvent-free medium. The effects of methanol amounts and enzyme concentration on the first-stage reaction, and the operational stability of Novozym 435 in the two-stage reaction were investigated. The addition of biodiesel into the reaction system prior to two-stage reaction prevented the lipase from deactivation caused by excess amounts of methanol. Contents of >95 wt% FAME could be achieved even after 15 cycle reactions.

Catalytic Conversion of Brown Grease to Green Diesel via Decarboxylation over Activated Carbon Supported Palladium Catalyst

The decarboxylation of brown grease (BG) to green diesel hydrocarbons over a 5 wt % Pd/C catalyst was investigated in semibatch and batch reactors. Catalytic deoxygenation of BG under H2–Ar occurs primarily via decarboxylation with the liquid products of primarily n-heptadecane and n-pentadecane. A 90% conversion of BG in a semibatch mode was obtained in 7 h. In contrast, in a batch reaction the conversion was roughly 40% in the same reaction time. However, by pretreating the “as received” BG with H2, the conversion in a batch reactor was increased 1.4-fold; and when the H2 to BG ratio was increased to 3/1 (mol/mol), the conversion was further improved. A complete conversion of BG into green diesel via decarboxylation is possible over 5% Pd/C catalyst at 300 °C and 1.5 MPa. This study demonstrates the feasibility of obtaining valuable green diesel biofuel from waste oil.

Biodiesel from grease interceptor to gas tank

AbstractThe need for sustainable biofuels has initiated a global search for innovative technologies that can sustainably convert nonfood bioresources to liquid transportation fuels. While 2nd generation cellulosic ethanol has begun to address this challenge, other resources including yellow and brown grease are rapidly evolving commercial opportunities that are addressing regional biodiesel needs. This review examines the technical and environmental factors driving the collection of trap FOG (Fats, Oils, and Greases), its chemical composition and technologies currently available and future developments that facilitate the conversion of FOG into biodiesel.

Simultaneous Analysis of Key Precursors and Products of Pretreatment and Transesterification of Brown Grease for Biodiesel Production

Simultaneous Analysis of Key Precursors and Products of Pretreatment and Transesterification of Brown Grease for Biodiesel ProductionAn analytical method for simultaneous analysis of the precursors and products of waste feedstock transesterification was assessed. The recommended method include micro-liquid liquid extraction (mLLE) of grease/biodiesel as sample preparation to produce an injectable solvent aliquot containing both free fatty acids and their methyl esters. 1 mL of sample is added into 4 mL of solvent mix and 30 mL...Author(s)Eva AgusLawrence J. PonSourceProceedings of the Water Environment FederationDocument typeConference PaperPublisherWater Environment FederationPrint publication date Oct, 2013ISSN1938-6478DOI10.2175/193864713813674027Volume / Issue2013 / 15Content sourceWEFTECCopyright2013Word count131

NiSO4/SiO2 Catalyst for Biodiesel Production from Free Fatty Acids in Brown Grease

In this paper, an NiSO4/SiO2 catalyst was prepared by impregnating an SiO2 support with an aqueous solution of NiSO4·6H2O. Through an esterification reaction using various catalysts including zeolite, SiO2, and H2SO4, free fatty acids (FFAs) in brown grease were converted to fatty acid methyl esters (FAMEs) as biodiesel products that were analyzed by gas chromatography–flame ionization detection, gas chromatography–mass spectrometry, and nuclear magnetic resonance. To optimize the esterification conditions, a molar ratio of methanol/brown grease from 1.57 to 3.70, a weight ratio of catalyst/brown grease from 0.75 to 1.75%, and reaction times from 30 min to 3 h at room temperature and atmospheric pressure were investigated. The chemical compositions of FFAs in brown grease were characterized as n-hexadecanoic acid (C16H32O2), 9,12-octadecadienoic acid (C18H32O2), and octadecanoic acid (C18H36O2). Biodiesels obtained from these FFAs included hexadecanoic methyl ester (C17H34O2), 9,12-octadecadienoic methyl ester (C19H34O2), 9-octadecenoic methyl ester (C19H36O2), and octadecanoic methyl ester (C19H38O2). Among the catalysts that were tested, the order of the catalytic activity was H2SO4>NiSO4/SiO2>zeolite>SiO2. Through the experiments conducted in this research, the optimized esterification conditions proved to be a methanol/brown grease molar ratio of 2.64, a catalyst/brown grease weight ratio of 1.00%, and a reaction time of 30 min. The use of NiSO4/SiO2 at room temperature might be significant for biodiesel production because it may allow the catalyst to be reused after recycling and lower the cost of biodiesel production without providing additional heating for the conversion of FFAs.

Commissioning of a biogas pilot plant: From brown grease to paper mill-generated organic wastes

The MeadWestvaco mill in Evadale, TX, USA, in conjunction with VOW Resources LLC, has constructed and commissioned a green biogas skid-mounted pilot plant to evaluate the potential of various organic waste streams to produce high-quality biogas. It is the fourth plant in the world incorporating this technical approach to biogas production. At initial startup, the plant used cow manure as organic feedstock. To commission the plant for verifying the VOW bioaugmentation process, the transition was made to using brown grease. After the brown grease commissioning trials are completed, the plant will be transitioned to a number of paper mill-generated organic wastes to acquire the design parameters and engineering data that will aid in construction of a full-scale biogas facility.

Brown and black grease suitability for incorporation into feeds and suitability for biofuels.

Waste grease lipids used in animal feeds have been the cause of food recalls in Europe, where such materials were incorporated into animal feedstuffs. This resulted in unwanted residues in human food. The composition of such lipid sources has been lacking. Seventeen composite trap grease and isolated brown grease samples were analyzed. Analytes included nutrients, metals, and volatile organic compounds. Analytes were selected for relevance to wastewater treatment and resource reuse potential. Moisture averaged 89.4% and the pH was 3.8. The 5-day biological oxygen demand was 32,531 mg/liter, solids were 7.5%, and fats, oil, and grease were 48,970 mg/liter. Non-polychlorinated biphenyl volatile organic compounds were surveyed. In the 17 grease samples, 14 contained an average of 102.5 μg/liter chloroform; 11 samples contained acetone, averaging 369 μg/liter; 9 samples contained 2-butanone, with an average of 484 μg/liter; and 8 contained an average of 710 μg/liter methylene chloride and toluene at 311 μg/liter. The mean concentration of copper in 17 composite samples ranged from 15 to 239 mg/liter, iron averaged 314 mg/liter, lead means ranged from 2.5 to 24 mg/liter, and magnesium averaged 975 mg/liter. It is hypothesized that food preparation facility cleaning and chlorinated cleaning-disinfection agents combined with the organics in the low-pH environment of the traps produce potentially carcinogenic compounds. It is recommended that these waste grease materials be used as a feedstock for biofuel.

Volatility of Mixtures of JP-8 with Biomass Derived Hydroprocessed Renewable Jet Fuels by the Composition Explicit Distillation Curve Method

In this paper, we apply the composition explicit distillation curve method to mixtures of JP-8 with hydroprocessed aviation fuels made from camelina (a genus within the flowering plant family Brassicaceae), from castor seed (Ricinus communis), and from waste brown grease used with the Fischer–Tropsch process. For the camelina fuel, the departures (with respect to JP-8) in volatility and in enthalpy of combustion are significant for mixtures with 25 and 50% (v/v) in JP-8. Mixtures with only 10% camelina fuel (v/v) show relatively minor departures. In all cases, the departures (with respect to JP-8) are to lower temperatures (higher volatility) and lower molar enthalpy of combustion. Mixtures of castor based fuel with JP-8 show essentially no departures in volatility or molar enthalpy of combustion up to the 40% distillate volume fraction. Subsequent to this distillate volume fraction, departures are very apparent, with mixtures showing lower volatility and higher molar enthalpy of combustion with higher volume fractions of castor based HRJ. Mixtures of the brown grease based fuel show departures to lower volatility and to higher molar enthalpy of combustion (with respect to JP-8) as the volume fraction of the brown grease SPK increases.

A Single Bio-based Catalyst for Bio-fuel and Bio-diesel

Current homogeneous catalysts used for commercial biodiesel synthesis are toxic and flammable. For Feedstock, their reaction requires refined oil which is a human food and expensive. In addition, due to contamination, the main byproduct of their reaction, glycerol is not usable for sale as a high value product and is land filled or burned as waste. Furthermore, the use of these catalysts in conversion of low cost feed-stocks such as waste oil and greases is not economical because their reactions produce soaps and clean up of the soap imposes additional processing cost to the biodiesel synthesis process. On the other hand, heterogeneous catalysts under development for biodiesel synthesis are either derived from non-renewable resources, or have problems with toxicity or stability. The solid heterogeneous bio-based catalysts are based on renewable resources, non-toxic, stable, effective, and low cost and are expected to work well for conversion of low cost feed-stocks such as waste oil and grease such as yellow, brown and black grease. In addition to catalyzing biodiesel synthesis, biobased catalysts can convert cellulosic agricultural waste to biofuel via saccarification followed by fermentation. Due to the abundance of cellulosic biomass in the nature, this reaction has great significance as it will affect the availability of not only biofuel from the fermentation of glucose, but also the availability of all organic chemicals and even hydrogen fuel from biomass. Because the catalytic active site in these catalysts are chemically bound, in contrast to other similar catalysts such as naphthalene sulfonic acid, the catalytic active sites of biobased catalysts will not break down, or leach. As a result, both the biodiesel and the glycerol by product will be free of catalyst contaminants. This allows the biodiesel to be safely burned and the glycerol byproduct to be sold as value-added commodity for pharmaceutical and cosmetic uses.

Does the Addition of High Strength Wastes Affect Biosolids Quality?

Does the Addition of High Strength Wastes Affect Biosolids Quality?San Francisco Water, Power, Sewer, the municipal agency charged with collecting and treating San Francisco's wastewater, has been conducting demonstration activities for a Fats, Oils, and Grease (FOG) to Biodiesel pilot at the City's Oceanside Water Pollution Control Plant (OSP). This project allows for the feeding of filtered trap waste or refined waste streams, such as brown grease directly to...Author(s)Natalie V. SierraMorayo NoibiBonnie M. JonesSourceProceedings of the Water Environment FederationDocument typeConference PaperPublisherWater Environment FederationPrint publication date Mar, 2012ISSN1938-6478DOI10.2175/193864712811693902Volume / Issue2012 / 2Content sourceResiduals and Biosolids ConferenceCopyright2012Word count138

Investigation of storage stability of biodiesels

The production and application of fuels from agricultural origin have emerged into focus in the last couple of years. A number of environmental, political and economical factors has confirmed and strengthened this process. The main reason of this tendency is the energy policy of the European Union, namely to reduce the green house gas emission of fuels, to decrease the significant dependence of EU on import energy and crude oil and to support rural development. To achieve these objectives, the European Union created the 2003/30/EC and 2009/28/EC directives, which regulate the application of biomass derived fuels. The main purpose is to promote the use of biofuels in transportation by recommending and specifying the share of the bio-components. This proposed value (10 energy % share of biofuels in the transport sector by 2020 in the EU) can be reached by the conversion of different triglyceride-containing biofeedstocks (e.g. vegetable oils, used frying oils, animal fats, algae oils, brown grease, etc.) to different biofuels orblending components. Nowadays FAME (Fatty Acid Methyl Esters), called as first generation biofuel, is mostly used as diesel bio blending component. But this biofuels due to its chemical structure the presence of the double bond in the molecule have a high reactivity with the oxygen, especially when it placed contacting air. That is why the long term storage stability of biodiesel is an important issue. The aim of our research work was to investigate the long term storage stability of biodiesel samples originated from different feedstock. The effects of the real storage conditionson the properties (induction period, acid value, iodine value, density, water content and kinematic viscosity) of the different biodiesels were investigated. Results showed that the acid number and the water content increased, while the induction period and the iodine number decreased with increasing storage time of biodiesel samples.

Performance of heterogeneous ZrO2 supported metaloxide catalysts for brown grease esterification and sulfur removal

In order to achieve a viable biodiesel industry, new catalyst technology is needed which can process a variety of less expensive waste oils, such as yellow grease and brown grease. However, for these catalysts to be effective for biodiesel production using these feedstocks, they must be able to tolerate higher concentrations of free fatty acids (FFA), water, and sulfur. We have developed a class of zirconia supported metaloxide catalysts that achieve high FAME yields through esterification of FFAs while simultaneously performing desulfurization and de-metallization functions. In fact, methanolysis, with the zirconia supported catalysts, was more effective for desulfurization than an acid washing process. In addition, using zirconia supported catalysts to convert waste grease, high in sulfur content, resulted in a FAME product that could meet the in-use ASTM diesel fuel sulfur specification (<500 ppm). Possible mechanisms of desulfurization and de-metallization by methanolysis were proposed to explain this activity.

Co-Location of Brown Grease to Biodiesel Production Facility at the Oceanside Wastewater Treatment Plant in San Francisco, CA

Co-Location of Brown Grease to Biodiesel Production Facility at the Oceanside Wastewater Treatment Plant in San Francisco, CA

Use of a whole-cell biocatalyst to produce biodiesel in a water-containing system

This study examined the use of a whole-cell biocatalyst to transesterify triglycerides, including high-Free Fatty Acid (FFA) waste greases, in a water-containing system. The whole-cell biocatalyst derived from Rhizopus oryzae (ATCC10260) was grown and reacted at room temperature without immobilization. The effectiveness of improving biodiesel yield through alteration of reaction temperature, additional alcohol, and additional transesterification reaction was also examined. Results showed that whole-cell biocatalyst was able to produce biodiesel with a yield of about 75% for virgin canola oil, 80% for waste vegetable oil and 55% for brown grease with a 72-hr transesterification reaction using no excess methanol. Elevating the reaction temperature to 35°C significantly diminished the yield. An additional dose of methanol with another 24 hours of reaction time or a second 72-hr reaction resulted in biodiesel yield approaching 90% and only 3% residual glycerides (mono-, di- and tri-glycerides). These results suggest that whole-cell biocatalysts are able to transesterify waste oils or greases that are high in FFA and contain water. Brown (trap) grease and similar degraded or complex greases may be good candidates for further whole-cell biocatalyst research.

Heterogeneous acid catalysts for biodiesel production: current status and future challenges

The reduction of oil resources and the consequent increasing price of oil distillates as well as the environmental concerns of conventional fuels has renewed and increased interest on the preparation of biofuels from renewable resources. One of those interests is nowadays focused on biodiesel, which is usually prepared from crude and refined triglyceride containing raw materials, such as vegetable oils, animal fats and wastes—for instance waste cooking oil and yellow and brown grease. Since several commercial interests converge on this kind of feedstock, one of the priorities being crops for human food supply, the research efforts on biodiesel production are diverting towards the use of low quality triglyceride-containing raw materials. Nevertheless, all of these feedstocks feature high water and free fatty acids (FFAs) content, which strongly affects the behaviour of conventional homogeneous base catalysts. These catalysts are primarily NaOH and KOH, but also NaOCH3 and KOCH3 are employed—as solutions in methanol—mainly in large-scale production plants. In this context, an appropriate solid acid catalyst which could simultaneously carry out esterification of FFAs and transesterification of triglycerides would be of great interest for biodiesel production. Moreover, a heterogeneous acid catalyst could be easily incorporated into a packed bed continuous flow reactor, simplifying product separation and purification and reducing waste generation. The present review attempts to provide a wide overview on the possibility of heterogeneous acid catalysts for biodiesel production replacing the homogeneous conventional process. In this way, three aspects of solid acid catalysis for biodiesel production will be reviewed. The first section deals with the solid acid-catalyzed esterification of FFAs, the second topic relates to the transesterification of triglycerides, while the third deals with solid acid-catalyzed transformation of bioglycerol into oxygenated compounds for biodiesel formulation.

High-purity fatty acid methyl ester production from canola, soybean, palm, and yellow grease lipids by means of a membrane reactor

High-purity fatty acid methyl ester (FAME) was produced from different lipids, such as soybean oil, canola oil, a hydrogenated palm oil/palm oil blend, yellow grease, and brown grease, combined with methanol using a continuous membrane reactor. The membrane reactor combines reaction and separation in a single unit, provides continuous mixing of raw materials, and maintains a high molar ratio of methanol to lipid in the reaction loop while maintaining two phases during the reaction. It was demonstrated that the membrane reactor can be operated using a very broad range of feedstocks at highly similar operating conditions to produce FAME. The total glycerine and free glycerine contents of the FAME produced were below the ASTM D6751 standard after a single reaction step. Under essentially the same reaction conditions, a conventional batch reaction was not able to achieve the same degree of FAME purity. The effect of the fatty acid composition of the lipid feedstocks on the FAME purity was also shown. It was demonstrated that, due to the fatty acid composition, FAME from virgin soybean oil and virgin canola oil was produced in the membrane reactor within ASTM specifications even without a water washing step.