Oxidation and low temperature properties of biofuels obtained from pyrolysis and alcoholysis of soybean oil and their blends with petroleum diesel

Diesel-like fuels were synthesized by a pyrolysis method using soybean oil (pyrodiesel, PD) and soybean soapstock (SPD), respectively, as starting material. These pyrodiesel samples were compared with soy biodiesel (BD) samples. All these three biofuels (PD, SPD and BD) and their blends with high sulfur (HSD) and low sulfur (LSD) diesel fuels were evaluated by measuring a number of fuel properties, such as oxidative stability, low-temperature performance, acid value and corrosion properties. Compared to BD blends, PD and SPD and their blends were found to have better oxidative stability, though inferior acid values. SPD and its blends have better flow performance at low-temperature compared to BD and PD blends. All the biofuels and their blends met the copper corrosion requirement prescribed by US and European standard. Based on the results reported here, pyrodiesels from these two-different feedstocks have potential and will require some upgrading or change in pyrolysis conditions, if they are to be used as fuel blending component.     

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.     

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.     

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.     

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.     

Performance,emission and combustion studies of a DI diesel engine using Distilled Tyre pyrolysis oil-diesel blends

Increase in energy demand, stringent emission norms and depletion of oil resources led the researchers to find alternative fuels for internal combustion engines. Many alternate fuels like Alcohols, Biodiesel, LPG, CNG etc have been already commercialized 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 some extent by pyrolysis. The properties of the Tyre pyrolysis oil (TPO) derived from waste automobile tyres were analyzed and compared with the petroleum products and found that it can also be used as a fuel for compression ignition engine. However, the crude TPO has a higher viscosity and sulphur content. The crude TPO was desulphurised and then distilled through vacuum distillation. In the present work, DTPO-diesel blends were used as an alternate fuel in a diesel engine without any engine modification. This paper presents the studies on the performance, emission and combustion characteristics of a single cylinder four stroke air cooled DI diesel engine running with the Distilled Tyre pyrolysis oil (DTPO).     

Fuel Properties of Biodiesel/Ultra-Low Sulfur Diesel (ULSD) Blends

Biodiesel is an alternative fuel and fuel extender easily derived from vegetable oil or animal fat. In 2006, the US Environmental Protection Agency mandated that maximum sulfur content of diesel fuels be reduced to 15 ppm to protect catalysts employed in exhaust after-treatment devices. Processing to produce this ultra-low sulfur petrodiesel (ULSD) alters fuel lubricity, density, cold flow, viscosity, and other properties. Consequently, there is a need to develop a better understanding of the basic fuel properties of biodiesel/ULSD blends. This work evaluates the effects of biodiesel volumetric blend ratio (V _BD) on cloud point (CP), kinematic viscosity (ν), specific gravity (SG), and refractive index (RI) of blends with petrodiesel. Properties measured for various blends of methyl esters of soybean oil (SME) and used cooking oil (UCOME) in ULSD were compared with those for blends with low sulfur (≤500 ppm) petrodiesel fuel (LSD). With respect to increasing V _BD, CP and SG increased and RI decreased with each parameter demonstrating a linear correlation. In contrast, ν showed a curvilinear relationship with respect to increasing V _BD. Calibration curves were derived from regression analyses to determine V _BD in biodiesel/ULSD blends from measurements of each individual property. While the models had generally high coefficients of regression (R ² > 0.986), SG models were most accurate for predicting V _BD to within 1.3 vol%.     

Predicting Temperature Dependent Viscosity for Unaltered Waste Soybean Oil Blended with Petroleum Fuels

Using vegetable oil based alternative fuels for diesel engines has grown in interest over recent years due to the rising cost of petroleum products and instability in the energy marketplace. One of the major hurdles to overcome in using vegetable oil as a diesel fuel is high viscosity. Here, we experimentally determine the viscosity of unaltered waste soybean oil (WSO) blended with petroleum fuels. Three blend viscosity models Arrhenius, Wright, and the ASTM D7152-05 Standard were evaluated for viscosity prediction accuracy over a temperature range of −10 to 40 °C. Results indicated that the Arrhenius method using volume fractions was the most accurate predictor of viscosity for binary blends made of WSO and diesel (2.31% absolute average deviation) as well as multi-component blends made from WSO, diesel, kerosene, and gasoline (8.72% absolute average deviation). An intermolecular interaction correction factor was empirically determined for each model in an effort to improve prediction accuracy for the multi-component blends. Using the correction constants improved the absolute average deviation for the Arrhenius method to 6.85%, 5.87% for the Wright method based on mass fractions, and 9.67% for the ASTM method based on mass fractions. The use of this correlation constant for the Arrhenius method was only helpful for blends containing more that 30% WSO, indicating that molecular interaction behavior only deviates significantly from ideality at these higher WSO fractions.     

Fuel consumption and emissions from a diesel power generator fuelled with castor oil and soybean biodiesel

This work investigates the impacts on fuel consumption and exhaust emissions of a diesel power generator operating with biodiesel. Fuel blends with 5%, 20%, 35%, 50%, and 85% of soybean biodiesel in diesel oil, and fuel blends containing 5%, 20%, and 35% of castor oil biodiesel in diesel oil were tested, varying engine load from 9.6 to 35.7 kW. Specific fuel consumption (SFC) and the exhaust concentrations of carbon dioxide (CO₂), carbon monoxide (CO), and hydrocarbons (HC) were evaluated. The engine was kept with its original settings for diesel oil operation. The results showed increased fuel consumption with higher biodiesel concentration in the fuel. Soybean biodiesel blends showed lower fuel consumption than castor biodiesel blends at a given concentration. At low and moderate loads, CO emission was increased by nearly 40% and over 80% when fuel blends containing 35% of castor oil biodiesel or soybean biodiesel were used, respectively, in comparison with diesel oil. With the load power of 9.6 kW, the use of fuel blends containing 20% of castor oil biodiesel or soybean biodiesel increased HC emissions by 16% and 18%, respectively, in comparison with diesel oil. Exhaust CO₂ concentration did not change significantly, showing differences lower than ±3% of the values recorded for diesel oil operation, irrespective of biodiesel type, concentration and the load applied. The results demonstrate that optimization of fuel injection system is required for proper engine operation with biodiesel.     

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.     

Oleochemicals as a fuel: Mechanical and economic feasibility

The status of vegetable oils as diesel fuel substitutes is currently dubious. Although it is fair to consider them as short-term emergency fuels (or, more desirably, low proportion supplements to diesel fuels), they present mechanical problems in long-term use that have not yet been solved. It is preferable to use these oils blended in small proportions with diesel fuels. Indirect-injection diesel engines have had fewer problems than direct-injection engines, whether the tests were performed with pure vegetable oil fuel or with vegetable oil/diesel fuel blends. The economic prospect for these fuels is not promising. In general, they are not and have not been economical alternatives to diesel fuel. Exceptions appear to have occurred recently in Brazil and the Philippines where low local prices for vegetable oils combined with high petroleum prices encouraged officials to use low proportion vegetable oil/diesel fuel blends. Nonetheless, current and long-term trends in petroleum and oilseed prices indicate that these fuels will probably not be price competitive within the near future. Emergency disruption of petroleum supplies completely changes the economic situation. Vegetable oils would be worth much more as a fuel during disruptions than otherwise; thus incentives could be strong to include these oils in the fuel supply, diverting them from the food supply.     

Emission characteristics of diesel, gas to liquid, and biodiesel-blended fuels in a diesel engine for passenger cars

The need for diversification of energy sources and reducing various emissions including CO₂ emission in diesel engine can be met with alternative diesel fuels such as gas to liquid (GTL) and GTL–biodiesel blends. But there should be a clear understanding of the combustion and engine-out emission characteristics for alternative fuels. In this respect, an experimental study was conducted on a 2.0 L 4 cylinders turbocharged diesel engine fuelled with those alternative diesel fuels to investigate the engine-out emission characteristics under various steady-state engine operating conditions. The results revealed that noticeable decreases in THC (22–56%) and CO (16–52%) emissions for GTL–biodiesel blends were observed, whereas NOx emissions for GTL–biodiesel blends increased by a maximum of 12% compared to diesel. With regard to particle size distributions (PSDs) for GTL–biodiesel blends, the particulate matter (PM) number concentration in accumulation mode decreased, as a result of the excess oxygen content in biodiesel. Contrary to the tendency in the accumulation mode, there was a slight increase in the PM number concentration in the nucleation mode under the operating conditions wherein the exhaust gas recirculation (EGR) strategy was applied. The total PM number concentration for G + BD40 decreased by a maximum of 46% compared to that for diesel. From these results of enhanced emission characteristics compared to diesel and GTL fuel, the potential for the use of GTL–biodiesel blends could be confirmed.     

Study of the performance,emission and combustion characteristics of a diesel engine using poon oil-based fuels

Experiments were conducted to study the performance, emission and combustion characteristics of a DI diesel engine using poon oil-based fuels. In the present work, poon oil and poon oil methyl ester are tested as diesel fuels in Neat and blended forms. The blends were prepared with 20% poon oil and 40% poon oil methyl ester separately with standard diesel on a volume basis. The reductions in smoke, hydrocarbon and CO emissions were observed for poon oil methyl ester and its diesel blend along with increased NO_x emission compared to those of standard diesel. However, a reduction in NO_x emission and an increase in smoke, hydrocarbon and CO emissions were observed for Neat poon oil and its diesel blend compared to those of standard diesel. The 40% poon oil methyl ester blend showed a 2% increase in brake thermal efficiency compared to that of standard diesel, whereas other fuels tested showed a decreasing trend. From the combustion analysis it was found that ignition delay was shorter for all fuels tested compared to that of standard diesel. The combustion characteristics of poon oil methyl ester and its diesel blend closely followed those of standard diesel.     

Study on the application of DME/diesel blends in a diesel engine

In this paper fuels, based on various DME to diesel ratios are investigated. Physical and chemical properties of DME and diesel display mutual solubility at any ratio. The vapor pressure of DME/diesel blends is lower than that of pure DME at the same temperatures and it decreases with an increase of diesel mass fraction in blends, which is beneficial to the elimination of vapor lock in the fuel supply system on CI engines. Performance, emission and other features of three kinds of DME/diesel blend fuels and diesels are evaluated in a four-cylinder test engine. By taking relative advantages of DME and diesel, the DME/diesel blends could achieve satisfactory properties in lubricity and atomization, which contributed to improvements in spray and combustion characteristics. Simultaneously, smoke emission could be reduced significantly with a little penalty on CO and HC emissions for DME/diesel blended engine at high loads, in comparison to diesel engine. NO_x emissions of the engine powered by DME/diesel blends are decreased somewhat. Moreover, the power output would be improved a little and NO_x emission could be reduced further if the fuel supply advance angle is retarded appropriately.     

Canola and high erucic rapeseed oil as substitutes for diesel fuel: Preliminary tests

A cooperative project using the facilities of the POS Pilot Plant Corporation, the Saskatchewan Research Council and the Agricultural Engineering Department, University of Saskatchewan, and funded by Agriculture Canada, was initiated in 1980 to investigate the feasibility of using canola and high erucic rapeseed oil as a replacement/extender to diesel fuel in direct-injection diesel engines. Work carried out included the documented production and refining of canola and R500 (high erucic) vegetable oils, preparation of methyl ester and of blends of all these fuels with methanol and ethanol. These fuels were evaluated by ASTM and improvised tests to determine their usefulness as diesel fuel. Engine tests involved a 2-cylinder Petter diesel and a 6-cylinder John Deere turbocharged diesel. Results were similar for both engines in short-term performance tests, and indicated that: (a) maximal power was essentially the same when burning canola oil as when burning diesel fuel; (b) specific fuel consumption was ca. 6% higher when burning canola oil, but because canola oil has a heating value 14% less than diesel fuel, the thermal efficiency is somewhat higher when operating on canola oil; (c) there were no starting problems down to 10 C; (d) there were fewer particulates in the exhaust when burning canola oil; and (e) there was generally less combustion noise when burning canola oil. The high viscosity of canola oil (ca. 35 times that of disel fuel at 20 C) poses a major problem in using the oil at low temperature. Blending with diesel fuel and the creation of a methyl ester from the canola oil both proved effective in reducing viscosity, but neither lowered the pour point apprecibly. Efforts on reduction of pour points and further work on blends and on heating the fuel are described.     

Effects of biodiesel on a DI diesel engine performance, emission and combustion characteristics

Experimental tests were investigated to evaluate the performance, emission and combustion of a diesel engine using neat rapeseed oil and its blends of 5%, 20% and 70%, and standard diesel fuel separately. The results indicate that the use of biodiesel produces lower smoke opacity (up to 60%), and higher brake specific fuel consumption (BSFC) (up to 11%) compared to diesel fuel. The measured CO emissions of B5 and B100 fuels were found to be 9% and 32% lower than that of the diesel fuel, respectively. The BSFC of biodiesel at the maximum torque and rated power conditions were found to be 8.5% and 8% higher than that of the diesel fuel, respectively. From the combustion analysis, it was found that ignition delay was shorter for neat rapeseed oil and its blends tested compared to that of standard diesel. The combustion characteristics of rapeseed oil and its diesel blends closely followed those of standard diesel.     

柴油润滑性及润滑性添加剂的研究进展

柴油的低硫化成为发展的必然趋势,柴油出现了润滑性差的现象。综述了影响柴油润滑性的因素和磨损机理及低硫柴油的润滑性添加剂,认为酯类是极具应用前景的抗磨剂;并对柴油润滑性的研究方向提出了建议。     

Sensitivity of Diesel Particulate Material Emissions and Composition to Blends of Petroleum Diesel and Biodiesel Fuel

A number of investigations have examined the impact of the use of biodiesel on the emissions of carbon dioxide and regulated emissions, but limited information exists on the chemical composition of particulate matter from diesel engines burning biodiesel blends. This study examines the composition of diesel particulate matter (DPM) emissions from a commercial agriculture tractor burning a range of biodiesel blends operating under a load that is controlled by a power take off (PTO) dynamometer. Ultra-low sulfur diesel (ULSD) fuel was blended with soybean and beef tallow based biodiesel to examine fuels containing 0% (B0), 25% (B25), 50% (B50), 75% (B75), and 100% (B100) biodiesel. Samples were then collected using a dilution source sampler to simulate atmospheric dilution. Diluted and aged exhaust was analyzed for particle mass and size distribution, PM_2.5 particle mass, PM_2.5 organic and elemental carbon, and speciated organic compounds. PM_2.5 mass emissions rates for the B25, B50, and B75 soybean oil biodiesel mixtures had 20%–30% lower emissions than the petroleum diesel, but B100 emissions were about 40% higher than the petroleum diesel. The trends in mass emission rates with the increasing biodiesel content can be explained by a significant decrease in elemental carbon (EC) emissions across all blending ranges and increasing organic carbon (OC) emissions with pure biodiesel. Beef tallow biodiesel blends showed similar trends. Nevertheless, it is important to note that the study measurements are based on low dilution rates and the OC emissions changes may be affected by ambient temperature and different dilution conditions spanning micro-environments and atmospheric conditions. The results show that the use of biodiesel fuel for economic or climate change mitigation purposes can lead to reductions in PM emissions and a co-benefit of EC emission reductions. Detailed speciation of the OC emissions were also examined and are presented to understand the sensitivity of OC emissions with respect to biodiesel fuel blends.

Copyright 2012 American Association for Aerosol Research     

Analytical study for atomization of biodiesels and their blends in a typical injector: Surface tension and viscosity effects

This study presents analytical comparisons of atomization characteristics of 7 biodiesels and 17 binary and ternary blends with D1 and D2 at 80 °C, using a direct injection injector. The atomization of a genetically modified vegetable oil – Captex 355 – and its corresponding biodiesel were also studied. Results from statistical analysis showed that B100 coconut biodiesel had similar atomization characteristics to D2, because of its similar properties, i.e. density, surface tension and viscosity. No significant difference in drop size was observed for all B5 blends, and B20 blends and B100 biodiesels of palm, soybean, cottonseed, peanut and canola. It implies these stocks of biodiesels and their blends can be used in a DI engine with similar atomization characteristics. Ternary biodiesel blends, with ⩽10 wt.% petroleum diesel, can yield equal drop sizes as some binary blends with large quantities of D1 and D2. The ternary biodiesel blends are likely to reduce pollution from exhaust emissions better than the biodiesel blends with D1 or D2. Captex 355 biodiesel had the best atomization characteristics of all the fuels studied. The Sauter mean diameter (SMD) produced by this fuel was up to 13% and 25% smaller than that of D1 and D2, respectively. The Captex 355 biodiesel may be used as a base in binary or ternary biodiesel blends to achieve better atomization than D1 and D2 in diesel engines.     

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.