共查询到18条相似文献,搜索用时 15 毫秒
1.
Low-temperature property and engine performance evaluation of ethyl and isopropyl esters of tallow and grease 总被引:5,自引:5,他引:0
Wen-Hsin Wu Thomas A. Foglia William N. Marmer Robert O. Dunn Carroll E. Goering Thomas E. Briggs 《Journal of the American Oil Chemists' Society》1998,75(12):1173-1178
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. 相似文献
2.
Wen-Hsin Wu Thomas A. Foglia William N. Marmer Robert O. Dunn Carroll E. Goering Thomas E. Briggs 《Journal of the American Oil Chemists' Society》1998,75(9):1173-1178
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. 相似文献
3.
This work examines low-temperature properties of triglyceride-based alternate fuels for direct-injection compression-ignition
engines. Methyl esters from transesterified soybean oil were studied as neat fuels and in blends with petroleum middle distillates
(No. 1 or No. 2 diesel fuel). Admixed methyl esters composed of 5–30 vol% tallowate methyl esters in soyate methyl esters
were also examined. Pour points, cloud points, and kinematic viscosities were measured; viscosities at cooler temperatures
were studied to evaluate effects of sustained exposure. Low-temperature filterability studies were conducted in accordance
with two standard methodologies. The North American standard was the low-temperature flow test (LTFT), and its European equivalent
was the cold-filter plugging point (CFPP). With respect to cold-flow properties, blending methyl esters with middle distillates
is limited to relatively low ester contents before the properties become preclusive. Under most conditions, cold-flow properties
were not greatly affected by admixing the methyl esters with up to 30 vol% tallowate (before blending). Least squares analysis
showed that both LTFT and CFPP of formulations containing at least 10 vol% methyl esters are linear functions of cloud point.
In addition, statistical analysis of the LTFT data showed a strong 1:1 correlation between LTFT and CP. This result may prove
crucial in efforts to improve low-temperature flow properties of alternate diesel fuels that contain methyl esters derived
from triglycerides. 相似文献
4.
Improving the low-temperature properties of alternative diesel fuels: Vegetable oil-derived methyl esters 总被引:14,自引:0,他引:14
R. O. Dunn M. W. Shockley M. O. Bagby 《Journal of the American Oil Chemists' Society》1996,73(12):1719-1728
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. 相似文献
5.
6.
R. O. Dunn 《Journal of the American Oil Chemists' Society》2002,79(7):709-715
Vegetable oils are an attractive renewable source for alternative diesel fuels. However, the relatively high kinematic viscosity
of vegetable oils must be reduced to make them more compatible with conventional compression-ignition engines and fuel systems.
Cosolvent blending is a low-cost and easy-to-adapt technology that reduces viscosity by diluting the vegetable oil with a
low-M.W. alcohol (methanol or ethanol). The cosolvent (A), which consists of one or more amphiphilic compounds, is added to solubilize the otherwise nearly immiscible oil-polar alcohol
mixture. This work investigates cold flow properties and phase equilibrium behavior associated with blends consisting of soybean
oil (SBO) and methanol where A=8∶1 (mol) n-butanol/oleyl alcohol; 6∶1 (mol) 2-octanol/triethylammonium linoleate; and 4∶1 (mol) 2-octanol/Unadol 40 (alcohols from SBO
FA); and a blend of 2∶1 (vol/vol) No. 2 diesel fuel/SBO and 95% ethanol where A=n-butanol. Cloud point (CP), pour point, cold filter plugging point (CFPP), and low-temperature flow test (LTFT) results were
compared with corresponding phase separation temperature (T
ϕ) data measured at equilibrium. Although CP data were measured under non-equilibrium experimental conditions, a nearly linear
correlation was found between T
ϕ and CP. Statistical analysis showed that T
ϕ may also be correlated with CFPP and LTFT. Analysis of heating and cooling DSC curves indicated that peak temperatures may
be employed to predict cold flow properties and T
ϕ behavior for SBO/cosolvent blends. Cooling curve parameters correlated more readily than heating curve parameters. Finally,
relatively low quantities of heat evolved during freezing indicated that crystallization in the SBO/cosolvent blends studied
in this work occurs easily during cooling. 相似文献
7.
Thermal analysis of alternative diesel fuels from vegetable oils 总被引:10,自引:6,他引:4
Robert O. Dunn 《Journal of the American Oil Chemists' Society》1999,76(1):109-115
The relatively poor cold-flow properties of monoalkyl esters of vegetable oils and animal fats (biodiesel) present a major
obstacle to their development as alternative fuels and extenders for combustion in direct injection compressionignition (diesel)
engines. In this work, differential scanning calorimetry (DSC) heating and cooling curves of methyl soyate (SME), methyl tallowate
(TME), SME/TME admixtures, and winterized SME were analyzed. Completion of melt, crystallization onset (Onset), and other
temperatures corresponding to melting and freezing peaks were correlated to predict cloud point (CP), pour point (PP), cold
filter plugging point (CFPP), and low-temperature flow test (LTFT) data. Effects of treating methyl esters with cold-flow
improvers were examined. Low-temperature flow properties of biodiesel may be accurately inferred from subambient DSC analyses
of high-melting or freezing (β-form) peaks. The temperature of maximal heat flow for freezing peaks gave the best accuracy
for predicting CP, PP, and CFPP, while freezing point gave the best accuracy for predicting LTFT. Onset also gave good correlations
with respect to predicting PP, CFPP, and LTFT. Cooling scan parameters were more reliable than heating scan parameters.
Presented at the 88th American Oil Chemists’ Society’s Annual Meeting & Expo, Seattle, Washington, May 11–14, 1997. 相似文献
8.
Production of alkyl esters from tallow and grease using lipase immobilized in a phyllosilicate sol-gel 总被引:2,自引:0,他引:2
An-Fei Hsu Kerby Jones William N. Marmer Thomas A. Foglia 《Journal of the American Oil Chemists' Society》2001,78(6):585-588
The lipase-catalyzed synthesis of alkyl esters from tallow and grease using Pseudomonas cepacia lipase (PS-30) immobilized within a phyllosilicate sol-gel matrix was investigated. The effects of the presence of alcohol and of the amount of enzyme used were studied. The matrix-immobilized PS-30 lipase effectively converted grease and tallow to ethyl esters in greater than 95% yield when using ethanol. The final conversion of grease or tallow to alkyl esters was aided by the addition of molecular sieves (0.4 wt% of substrates) to the reaction mixture. The matrix-immobilized PS-30 enzyme was easily recovered and could be reused at least five times without losing its activity. Accordingly, the phyllosilicate sol-gel immobilized PS-30 lipase is potentially useful for the economic production of biodiesel fuel. 相似文献
9.
Statistical comb‐type copolymers of styrene (Sty) and stearyl methacrylate (C18 MA) with varying [styrene]:[C18MA] ratios were synthesized by a controlled/living radical polymerization technique called atom transfer radical polymerization. The polymeric materials were evaluated in selected SASOL Fischer Tropsch gas‐to‐liquid diesels as possible cold flow improvers. Crystallization studies revealed that as the styrene content of the copolymer increased, a crystal growth inhibition mechanism was exhibited. With an increase in styrene content of the copolymer, differential scanning calorimetry and the cloud filter plugging point (CFPP) revealed a delay in onset of crystallization and lowered CFPP, respectively, whereas low‐temperature microscopy indicated modifications and size reduction of wax crystals. However, there appeared to be a styrene content, beyond which the additive's efficiency decreased. Homopolymer and copolymers with the highest styrene content led to long unfavorable needle‐shaped crystals. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
10.
11.
A new kind of rosin‐type nucleating agent for polypropylene (PP), the cocrystal of dehydroabietic acid, potassium dehydroabietate, and sodium dehydroabietate, was prepared, and the effects of the nucleating agents on the mechanical and crystallization properties of PP were also studied. The results of differential scanning calorimetry and X‐ray diffraction proved that the cocrystal of dehydroabietic acid and compound alkali dehydroabietate was formed rather than a simple blend of dehydroabietic acid and single alkali dehydroabietate. When it was added to PP, the size of the PP spherulite decreased; the mechanical properties, crystallization temperature, and transparency of PP were substantially improved. Thus, the cocrystal of dehydroabietic acid, potassium dehydroabietate, and sodium dehydroabietate acted as a more effective nucleating agent for PP. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2137–2141, 2003 相似文献
12.
The morphology and mechanical properties of isotactic polypropylene (iPP) and poly(ethylene‐co‐methyl acrylate) (EMA) blends were investigated. Various EMA copolymers with different methyl acrylate (MA) comonomer content were used. iPP and EMA formed immiscible blends over the composition range studied. The crystallization and melting reflected that of the individual components and the crystallinity was not greatly affected. The size of the iPP crystals was larger in the blends than those of pure iPP, indicating that EMA may have reduced the nucleation density of the iPP; however, the growth rate of the iPP crystals was found to remain constant. The tensile elongation at break was greatly increased by the presence of EMA, although the modulus remained approximately constant until the EMA composition was greater than 20%. EMA with a 9.0% MA content provided the optimum effect on the mechanical properties of the blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 175–185, 2003 相似文献
13.
Fuel properties and nitrogen oxide emission levels of biodiesel produced from animal fats 总被引:2,自引:0,他引:2
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 (NOx) 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 NOx emission levels (3.2–6.2%) than did the soy-based B20 fuel. 相似文献
14.
Polypropylene (PP)/polystyrene (PS) blends modified with reactive monomers, such as maleic anhydride (MAH) and styrene (St), and in situ formed PP/PS blends were prepared by melting extrusion. The crystallization and melting behavior and the dynamic mechanical properties of the PP/PS blends, including the structure of the grafted copolymer, were investigated with differential scanning calorimetry, dynamic mechanical analysis, and Fourier transform infrared. The results indicated that the addition of MAH hardly influenced the crystallization temperature of PP in the blends, but the addition of MAH and St increased the crystallization temperature of PP in its blends. The blends showed no remarkable variety for the melting temperature, but the shapes of the melting peaks were influenced by the addition of the reactive monomers. In addition, a significant increase in the storage and loss moduli of all the modified PP/PS blends was observed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2038–2045, 2005 相似文献
15.
The crystallization behavior of polypropylene (PP) copolymer obtained by in situ reactor copolymerization with or without a nucleating agent and/or nano‐CaCO3 particles was investigated both by thermal analysis and by polarized light microscopy. The Avrami model is successfully used to describe the crystallization kinetics of the studied copolymer. The results of the investigation show that a dramatic decrease of the half‐time of crystallization t1/2, as well as a significant increase of the overall crystallization rate, are observed in the presence of the nucleating agent. These effects are further promoted in the presence of the nano‐CaCO3 particles. The incorporation of the nucleating agent and nano‐CaCO3 particles into PP copolymer remarkably improved the mechanical properties and heat distortion temperature. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 431–438, 2004 相似文献
16.
S. Yamaguchi Y. W. Leong T. Tsujii M. Mizoguchi U. S. Ishiaku H. Hamada 《应用聚合物科学杂志》2005,98(1):294-301
A previous study has shown that the adhesion between the film and substrate of film‐insert injection‐molded poly(propylene) (PP) film/PP substrate was evident with the increases in barrel temperature and injection holding pressure. In this second part of the research work, the crystallinity at the interfacial region (i.e., region between the film and the injected substrate) was extensively studied using FTIR imaging, polarized light microscopy, and DSC in an attempt to determine the level of influence that crystallinity has on the interface and bulk mechanical properties. Consequently, a more thorough and clearer picture of the influence of the inserted film on the interfacial crystallinity and subsequently the substrate mechanical properties, such as peel strength and impact strength, has been revealed. The initial proposition that crystallinity could enhance film–substrate interfacial bonding has been confirmed, judging from the higher peel strength with increasing crystallinity at the interfacial region. Nevertheless, the change in crystallinity was not only confined to the interfacial region. With the film acting as heat‐transfer inhibitor between the injected resin and the mold wall, the total crystal structure of the substrate was substantially altered, which subsequently affected the bulk mechanical properties. The lower impact strength of film‐insert injection‐molded samples compared to that of samples without film inserts provided evidence of how the film could impart inferior properties to the substrate. The difference in cooling rate between the substrate and film might also cause other defects such as warpage and/or residual stress build‐up within the product. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 294–301, 2005 相似文献
17.
柠檬酸-新戊二醇-柠檬酸-环烷酸-十八醇爪形大分子的合成、表征与降滤性质 总被引:1,自引:0,他引:1
以新戊二醇、柠檬酸为原料,以对甲苯磺酸为催化剂,甲苯为溶剂,在120℃油浴中反应,合成了以新戊二醇为核的多羟基多酸爪状物小分子柠檬酸-新戊二醇-柠檬酸(CNC);再利用酯化反应依次与带有功能化基团的环烷酸、十八醇分别在140℃和180℃油浴中接枝,合成了新型的多元酯类爪形大分子柠檬酸-新戊二醇-柠檬酸-环烷酸-十八醇(CNC-NO)。用1HNMR及IR对合成的两种化合物进行了结构表征;结果表明,合成的CNC和CNC-NO与所设计的分子结构吻合。用元素分析确定了CNC的化学组成为C17H24O14。合成的CNC-NO不溶于水,溶于非极性的有机溶剂。将CNC-NO按600μg/g添加到轻柴油中,柴油的冷滤点可降低6℃。 相似文献
18.
A series of poly(azomethine ester) copolymers were synthesized by the solution polycondensation method with different diamines. The synthesized polymers were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry (DSC), hot‐stage polarized microscopy, wide‐angle X‐ray diffraction, and solution viscosity. All polymers showed good thermal stability. The thermotropic liquid‐crystalline properties were examined by DSC and by microscopic observations. Except for one, all of the polymers showed nematic liquid‐crystalline behavior. The effects of temperature on crystallinity and the substituent on solubility, thermal stability, melting temperature, and viscosity were also studied. The voluminosity and shape factor were also computed from the viscosity data. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 153–160, 2003 相似文献