Comparing the lubricity of biofuels obtained from pyrolysis and alcoholysis of soybean oil and their blends with petroleum diesel

A diesel-like fuel, pyrodiesel (PD), was synthesized by a pyrolysis method using soybean oil as starting material. Some physical properties of the material were studied, both neat and in blends with high-sulfur (HSD) and low-sulfur (LSD) diesel fuels, and compared with blends of biodiesel (BD) in fossil fuels. It was observed using different methods that the lubricity of biobased fuels obtained after the transesterification or pyrolysis of soybean oil is superior to LSD and HSD and also that the lubricity of diesel fuels are enhanced when either BD or PD are added. Based on the results reported herein, PD is a viable alternative to BD for use in compression-ignition engines.     

Fuel properties and nitrogen oxide emission levels of biodiesel produced from animal fats

FAME of lard, beef tallow, and chicken fat were prepared by base-catalyzed transesterification for use as biodiesel fuels. Selected fuel properties of the neat fat-derived methyl esters (B100) were determined and found to meet ASTM specifications. The cold-flow properties, lubricity, and oxidative stability of the B100 fat-derived fuels also were measured. In general, the cold-flow properties of the fat-based fuels were less desirable than those of soy-based biodiesel, but the lubricity and oxidative stability of the fat-based biodiesels were comparable to or better than soy-based biodiesel. Nitrogen oxide (NO_x) emission tests also were conducted with the animal fat-derived esters and compared with soybean oil biodiesel as 20 vol% blends (B20) in petroleum diesel. The data indicated that the three animal fat-based B20 fuels had lower NO_x emission levels (3.2–6.2%) than did the soy-based B20 fuel.     

Exhaust emissions and fuel properties of partially hydrogenated soybean oil methyl esters blended with ultra low sulfur diesel fuel

Important fuel properties and emission characteristics of blends (20 vol.%) of soybean oil methyl esters (SME) and partially hydrogenated SME (PHSME) in ultra low sulfur diesel fuel (ULSD) were determined and compared with neat ULSD. The following changes were observed for B20 blends of SME and PHSME versus neat ULSD: improved lubricity, higher kinematic viscosity and cetane number, lower sulfur content, and inferior low-temperature properties and oxidative stability. With respect to exhaust emissions, B20 blends of PHSME and SME exhibited lower PM and CO emissions in comparison to those of neat ULSD. The PHSME blend also showed a significant reduction in THC emissions. Both SME and PHSME B20 blends yielded small increases in NO_x emissions. The reduction in double bond content of PHSME did not result in a statistically significant difference in NO_x emissions versus SME at the B20 blend level. The test engine consumed a greater amount of fuel operating on the SME and PHSME blends than on neat ULSD, but the increase was smaller for the PHSME blend.     

The evaluation of viscosity and density of blends of Cyn-diesel pyrolysis fuel with conventional diesel fuel in relation to compliance with fuel specifications EN 590:2009

The production of synthetic fuels from alternative sources has increased in recent years as a cleaner, more sustainable source of transport fuel is now required. In response to European renewable energy targets, Ireland has committed, through the Biofuels Obligation Scheme of 2008, to producing 4% of transport fuels from biofuels by 2010 and 10% by 2020. In order to be suitable for sale in Europe, diesel fuels and biodiesels must meet certain European fuel specifications outlined in the EN 590:2004 and EN 14214:2009 standards. The aim of this project is to prepare blends of varying proportions of synthetic diesel fuel (Cyn-diesel), produced from the pyrolysis of plastic, versus regular fossil diesel. The viscosity (mm²/s) and density (kg/m³) of these blends as well as of the regular diesel fuel were analysed in relation to compliance with the European fuel standard EN 590.     

Fuel properties of tallow and soybean oil esters

Fuel properties of beef tallow, soybean oil, their esters, and blends with No. 2 diesel fuel and ethanol were determined. Fuel properties tested were viscosity, specific gravity, API gravity, distillation ranges, calculated cetane index, energy content, flash point, water content, sulfur content, carbon residue, particulate matter, acid value, copper-strip corrosion test, ash content, melting point, cloud point, and pour point. Gas-chromatographic analyses of tallow, soybean oil, and their esters were performed to determine their major constituents. Viscosities of soybean oil and tallow were significantly reduced by esterification. Other fuel properties of the esters and their blends with No. 2 diesel fuel and ethanol were similar to the properties of No. 2 diesel fuel.     

Key properties and blending strategies of hydrotreated vegetable oil as biofuel for diesel engines

Hydrotreating catalysis is becoming a promising alternative to transesterification for the production of biofuels derived from vegetable oils. They have potential advantages with respect to both biodiesel fuels and petroleum-derived diesel fuels in terms of production costs, engine emissions and adaptability to current engine designs, but they have also some limitations which may restrict their capability to replace diesel fuels. Those fuel properties considered the most restrictive ones were measured on different blends of HVO (selected among the variety of names given to these fuels) with a winter ultra low sulfur diesel fuel (in 10, 20, 25, 30, 35, 40, 45, 50, 55, and 75 vol.%) in order to propose some blending strategies to optimize engine performance and emissions, to protect the engine components and to keep the vehicle operability. The results obtained show that the main restrictions are imposed by lubricity and cetane number, and, in case of cold regions, also by cold flow properties. A compromise between lubricity and derived cetane number would lead to a recommendation for low or medium HVO concentrations, and blends with concentrations above 50% would not be recommended. Density and viscosity would not impose direct blending restrictions, although the reductions in density could provide some economic savings and some flexibility to refineries. The loss of heating value per unit volume (and consequently the expected increase in fuel consumption) would be lower than 3% in blends up to 50% in volume. Finally, the sooting tendency of the blends is sharply reduced, indicating lower engine PM emissions and reduced need for regeneration of diesel particulate filters.     

Low-temperature property and engine performance evaluation of ethyl and isopropyl esters of tallow and grease

Three monoalkyl fatty acid esters derived from tallow and grease were prepared by lipase-catalyzed transesterification and evaluated as prospective diesel engine fuels. The low-temperature properties of the esters, both neat and as 20% blends in No. 2 diesel fuel, were evaluated. Those properties included cloud point, pour point, cold filter plugging point, low-temperature flow test, and crystallization onset temperature. Other properties of the esters, such as kinematic viscosity, heating value, and calculated cetane number, also were determined. All three esters had acceptable physical and low-temperature properties, as well as acceptable fuel properties at the 20% level in diesel blends. Engine performance and emissions for the ester blends were determined in a direct-injection, matched two-cylinder diesel engine. Among the monoalkyl esters studied, ethyl greasate had better properties and engine performance characteristics than the two tallow esters. For the latter esters, isopropyl tallowate had better properties than ethyl tallowate. Presented in part at the 88th Annual Meeting of American Oil Chemists’ Society, Seattle, WA, May 1997.     

Assessment of pyrolysis oil as an energy source for diesel engines

This paper describes an experimental study of using tyre pyrolysis oil (TPO) obtained from waste automobile tyres by vacuum pyrolysis method, as a fuel in diesel engine. In this work, performance and emission parameters of a single cylinder water cooled diesel engine running on TPO diesel reference fuel (RF) blends in steps of 20% on volume basis of TPO, viz. TPO20 up to TPO70 were used as fuels and the results compared with diesel operation. Results indicated that reliable operation can be achieved up to 70% of TPO diesel blends. Thermal efficiencies were lower compared to diesel operation. Higher smoke, HC and CO emissions were recorded in the experimentation. Oil sticking was occasionally found on the nozzle stem and sac. There was no corrosion in the injection system after running the engine with TPO–RF blends.     

Characterization of the key fuel properties of methyl ester-diesel fuel blends

Characterizing of the fuel properties of diesel fuels, alternative fuels and their blends can assist the researchers who work on alternative fuels for diesel engines. Therefore, in this study, methyl esters were produced from five edible vegetable oils (sunflower, soybean, canola, corn and cottonseed) and blended with two different diesel fuels at 2%, 5%, 10%, 20%, 50% and 75% on a volume basis to characterize the key fuel properties of the blends such as density, viscosity, pour point, distillation temperatures and flash point. The results showed that the fuel properties of the blends were very close to those of diesel fuels at low concentrations upto 20% of methyl esters.     

Improving the low-temperature properties of alternative diesel fuels: Vegetable oil-derived methyl esters

This work explores near-term approaches for improving the low-temperature properties of triglyceride oil-derived fuels for direct-injection compression-ignition (diesel) engines. Methyl esters from transesterified soybean oil were evaluated as a neat fuel and in blends with petroleum middle distillates. Winterization showed that the cloud point (CP) of methyl soyate may be reduced to −16°C. Twelve cold-flow additives marketed for distillates were tested by standard petroleum methodologies, including CP, pour point (PP), kinematic viscosity, cold filter plugging point (CFPP), and low-temperature flow test (LTFT). Results showed that additive treatment significantly improves the PP of distillate/methyl ester blends; however, additives do not greatly affect CP or viscosity. Both CFPP and LTFT were nearly linear functions of CP, a result that compares well with earlier studies with untreated distillate/methyl ester blends. In particular, additives proved capable of reducing LTFT of neart methyl esters by 5–6°C. This work supports earlier research on the low-temperature properties; that is, approaches for improving the cold flow of methyl ester-based diesel fuels should continue to focus on reducing CP.     

Oxidative Stabilities of Enzymatically Interesterified Fats Containing Conjugated Linoleic Acid

Interesterified fat was produced from soybean oil (SBO) and palm stearin (PS) using two different weight ratios of substrates. Conjugated linoleic acid (CLA; 10?wt% on the weight of SBO and PS) was used as a functional fatty acid. Interesterification and acidolysis was simultaneously carried out to exchange fatty acids and incorporate CLA in the triacylglycerol (TAG) backbone, respectively, using immobilized lipase. Comparative study was carried out between interesterified fats and blends (before interesterification) for the quantification of physical properties (i.e., solid fat content, melting and crystallization behavior) and oxidative stability. In the interesterified fat 5.2–6.1?% CLA was incorporated in the TAG backbone. Blends showed higher solid fat content (SFC) and melting point than interesterified fat at each measured temperature. The Rancimat test was performed for the oxidative stability where the interesterified fat showed significantly lower induction time than physical blends. After the addition of antioxidants such as butylated hydroxytoluene (BHT), rosemary extract, tertiary butylhydroquinone (TBHQ), propyl gallate (PG), etc. into the interesterified fat, the induction time was significantly increased. On the other hand, different deacidification methods (alkaline, batch deodorized and short path distillation) were performed after interesterification to remove the free fatty acids. After deacidification, oxidative stability of alkaline deacidified sample showed significantly (P?≤?0.05) longer induction time compared to short path distillation (SPD) and physically deacidified samples. In this study, interesterified functional fat that may have a potential functionality for the margarines and shortenings were produced and their oxidative stability was observed.     

Application of chemical fractionation methods for characterisation of biofuels,waste derived fuels and CFB co-combustion fly ashes

In the important efforts to decrease the net CO₂ emissions to the atmosphere, new, alternative fuels are being included in the fuel mixes used in utility boilers. However, these fuels have ash properties that are different from those of the traditionally used fuels and in some cases technical problems, such as ash fouling and corrosion occur due to this. Therefore, diagnostic and predictive methods are developed and used to avoid such problems. Determination of the chemical association forms of important elements, such as potassium and sodium, in the fuel by chemical fractionation is a method well defined for coal and biofuels, such as wood pellets, bark and forest residues. Chemical fractionation is a step by step leaching method extracting water soluble salts in the first step, ion exchangeable elements, such as organically associated sodium, calcium and magnesium in the second step and acid soluble compounds such as carbonates and sulfates in the third step. The solid residue fraction consists of silicates, oxides, sulfides and other minerals. The compound extracted in the two first steps is considered reactive in the combustion with a few exceptions. In this work, it has been applied to some waste fuels, i.e. sewage sludge, straw and refuse derived fuel (RDF), as well as to coal and wood. The present work also includes results from combustion tests in a fluidised bed boiler where three blends of the investigated fuels were used. The fractionation results for the fuel blends are weighted results of the fractionations of the pure fuels discussed above which are compared with fractionations of their corresponding fly ashes. The co-combustion strategy gave very good results in reducing ash problems. Possible chemical mechanisms involved are discussed in the article.     

A comparative study on the performance, emission and combustion studies of a DI diesel engine using distilled tyre pyrolysis oil–diesel blends

Alternate fuels like ethanol, biodiesel, LPG, CNG, etc., have been already commercialised in the transport sector. In this context, pyrolysis of solid waste is currently receiving renewed interest. The disposal of waste tyres can be simplified to a certain extent by pyrolysis. In the present work, the crude tyre pyrolyisis oil (TPO) was desulphurised and then distilled through vacuum distillation. Also, two distilled tyre pyrolysis oil (DTPO)–diesel fuel (DF) blends at lower and higher concentrations were used as fuels in a four stroke single cylinder air cooled diesel engine without any engine modification. The results were compared with diesel fuel (DF) operation. Results indicate that the engine can run with 90% DTPO and 10% diesel fuel.     

清洁燃料的非加氢脱硫技术进展

日益严格的环保法规,对生产低硫、超低硫清洁燃料技术提出了更高要求。介绍了汽柴油脱硫的相关技术,包括加氢脱硫和非加氢脱硫。着重介绍了吸附、氧化和生物脱硫技术进展,同时简要介绍了萃取、膜分离及络合脱硫等工艺。与加氢脱硫相比,非加氢脱硫技术具有操作条件温和、投资及操作费用低等优点,具有更加广阔的发展前景。     

Fuel production from waste vehicle tires by catalytic pyrolysis and its application in a diesel engine

An alternative fuel production was performed by pyrolysis of waste vehicle tires under nitrogen (N₂) environment and with calcium hydroxide (Ca(OH)₂) as catalyst. The sulfur content of liquids obtained were reduced by using Ca(OH)₂. The liquid fuel of waste vehicle tires(TF) was then used in a diesel engine to blend with petroleum diesel fuel by 5%(TF5), 10%(TF10), 15%(TF15), 25%(TF25), 35%(TF35), 50%(TF50), and 75%(TF75) wt. and pure (TF100). Performance characteristics such as engine power, engine torque, brake specific fuel consumption (bsfc) and exhaust temperature and emission parameters such as oxides of nitrogen (NOx), carbon monoxides (CO), total unburned hydrocarbon (HC), sulfur dioxides (SO₂) and smoke opacity of the engine operation with TF and blend fuels of TF-diesel were experimentally investigated and compared with those of petroleum diesel fuel. It was concluded that the blends of pyrolysis oil of waste tires TF5, TF10, TF25 and TF35 can efficiently be used in diesel engines without any engine modifications. However, the blends of TF50, TF75 and TF100 resulted considerably to high CO, HC, SO₂ and smoke emissions.     

Low-temperature property and engine performance evaluation of ethyl and isopropyl esters of tallow and grease

Three monoalkyl fatty acid esters derived from tallow and grease were prepared by lipase-catalyzed transesterification and evaluated as prospective diesel engine fuels. The low-temperature properties of the esters, both neat and as 20% blends in No. 2 diesel fuel, were evaluated. Those properties included cloud point, pour point, cold filter plugging point, low-temperature flow test, and crystallization onset temperature. Other properties of the esters, such as kinematic viscosity, heating value, and calculated cetane number, also were determined. All three esters had acceptable physical and low-temperature properties, as well as acceptable fuel properties at the 20% level in diesel blends. Engine performance and emissions for the ester blends were determined in a direct-injection, matched two-cylinder diesel engine. Among the monoalkyl esters studied, ethyl greasate had better properties and engine performance characteristics than the two tallow esters. For the latter esters, isopropyl tallowate had better properties than ethyl tallowate. Presented in part at the 88th Annual Meeting of American Oil Chemists’ Society, Seattle, WA, May 1997.     

Rheological studies on a slurry biofuel to aid in evaluating its suitability as a fuel

Biomass is an often abundant, renewable, low ash and low sulfur fuel. Due to these properties, biofuels are promising alternatives for traditional petroleum-based fuel applications; however, traditional biofuels for internal combustion engines are not cost competitive with gasoline, diesel or fuel oils. One method to reduce the cost of biofuels is to use slurry fuels which have a potential lower cost than liquid biofuels due to high conversion efficiencies. Slurry biofuels, such as a mixture of corn and water, could provide a biofuel alternative for diesel engines, pressurized gasifiers and heating oil applications such as burners or gas turbines. Use of these biomass slurries poses important questions about their stability and suitability for practical applications in internal combustion engines and combustors.This work reports rheology data for stable corn-starch water slurries (CSWS) which used a polyacrylic acid thickener to eliminate settling of the slurry and to provide desirable shear-thinning behavior for most of the compositions evaluated. The effect of shear rate on the viscosity of the CSWS was studied using a BOHLIN-controlled stress (CS) rheometer. The well-known Ostwald—de Waele power law and Sisko models for viscosity fit the data. The effect of corn starch content, thickener content and temperature on the viscosity of CSWS was also studied. The favorable shear thinning properties were observed for starch contents up to 45% starch and should aid pumping, injection and spraying. The lower heating values of the slurries, however, are undesirably low.     

Pyrolytic characteristics of blended coal and woody biomass

Pyrolytic characteristics of biomass/coal mixtures were investigated under conditions pertinent to pulverised fuel boilers. It was found that the mixtures of biomass/coal follow the behaviour of their parent materials in an additive manner. The two fuels did not chemically interact under inert conditions indicating a general lack of synergistic effects. As such, the yield of the major pyrolysis products is linearly proportional to the percentage of biomass and coal in the mixture. Even the compositions of the gaseous products from blended samples are linearly proportional to those of their parent fuels. These findings can potentially help to understand and predict the behaviour of biomass/coal blends in practical systems.     

Physical and chemical properties of ethanol-diesel fuel blends

This paper discusses the physical-chemical properties of ethanol-diesel fuel blends. The attention is focused on the properties which influence the injection and engine characteristics significantly. Main properties have been investigated experimentally. The analysis of experimentally obtained fuel properties of tested fuels and their influence on engine characteristics are presented. Physical and chemical properties of diesel fuel and ethanol-diesel fuel blends were measured according to requirements and test methods for diesel fuel (EN590, 2003). The tested fuels were neat mineral diesel fuel (D100), 5% (v/v) ethanol/diesel fuel blend (E05D95), 10% (v/v) ethanol-diesel fuel blend (E10D90) and 15% (v/v) ethanol-diesel fuel blend (E15D85). It has been proved that, for ethanol-diesel fuel blends, some additives are necessary to keep stability under low temperature conditions. Also, cold weather properties test, such as cloud point and pour point tests are negatively affected by phase separation. The rest of the properties, excepting flash point, were within diesel fuel standard specifications. Based on this study, it can be concluded that using additives to avoid phase separation and to raise flash point, blends of diesel fuel with ethanol up to 15% can be used to fuel diesel engines if engine performance tests corroborate it.     

Temperature-dependent kinematic viscosity of selected biodiesel fuels and blends with diesel fuel

The kinematic viscosities of four biodiesel fuels—two natural soybean oil methyl esters, one genetically modified soybean oil methyl ester, and one yellow grease methyl ester—and their 75, 50, and 25% blends with No. 2 diesel fuel were measured in the temperature range from 20 to 100°C in steps of 20°C. The measurements indicated that all these fuels had viscosity-temperature relationships similar to No. 2 diesel fuel, which followed the Vogel equation as expected. A weighted semilog blending equation was developed in which the mass-based kinematic viscosity of the individual components was used to compute the mixture viscosity. A weight factor of 1.08 was applied to biodiesel fuel to account for its effect on the mixture viscosity. The average absolute deviation achieved with this method was 2.1%, which was better than the uncorrected mass average blending equation that had an average absolute deviation of 4.5%. The relationship between the viscosity and the specific gravity of biodiesel fuels was studied. A method that could estimate the viscosity from the specific gravity of biodiesel fuel was developed. The average absolute deviation for all the samples using this method was 2.7%. The accuracy of this method was comparable to the weighted mass-based semilog blending equation.