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1.
Jude A. Onwudili 《Fuel》2010,89(2):501-15
A viscous waste derived from a bio-diesel production plant, in the form of crude glycerol, was reacted under subcritical and supercritical water conditions and the product composition determined in relation to process conditions. Preliminary analysis of the original sample showed that the main constituent organic compounds were methanol (20.8 wt.%), glycerol (42.3 wt.%) and fatty acid methyl esters (33.1 wt.%). Uncatalyzed reforming experiments were carried out in a 75 ml Hastelloy-C batch reactor at temperatures between 300 °C and 450 °C and pressures between 8.5 MPa and 31 MPa. Oil/wax constituted more than 62 wt.% of the reactions products. At 300 °C, the main product was a waxy material containing mainly glycerol and fatty acid methyl esters. As the temperature increased to supercritical water conditions, low viscosity oils were produced and all of the glycerol was reacted. The oils contained mainly saturated and unsaturated fatty acid esters as well as their decomposition products. The gaseous products were carbon dioxide, hydrogen and methane and lower concentrations of carbon monoxide and C2-C4 hydrocarbons. No char formation was observed. However, during alkaline gasification with sodium hydroxide at 380 °C, the reaction products included a gaseous effluent containing up to 90% by volume of hydrogen, in addition to oil and significant amount of whitish solid residue (soap). Sodium hydroxide influenced the production of hydrogen via water-gas shift by the removal of carbon dioxide as sodium carbonate, but also decreased oil product possibly through saponification.  相似文献   

2.
Hydroprocessed rapeseed oil as a source of hydrocarbon-based biodiesel   总被引:1,自引:0,他引:1  
This paper deals with the hydroprocessing of rapeseed oil representing a perspective technological way for production of biocomponents in diesel fuel range. Rapeseed oil was hydroprocessed at various temperatures (260-340 °C) under a pressure of 7 MPa in a laboratory flow reactor. Three Ni-Mo/alumina hydrorefining catalysts were used. Reaction products were analyzed using several gas-chromatographic methods. Reaction products contained water, hydrogen-rich gas and organic liquid product (OLP). The main components of OLP were identified as C17 and C18n-alkanes and i-alkanes. At a low reaction temperature, OLP contained also free fatty acids and triglycerides. At reaction temperatures higher than 310 °C, OLP contained only hydrocarbons of the same nature as hydrocarbons present in diesel fuel. Influence of reaction temperature and catalyst on the composition of reaction products is discussed.  相似文献   

3.
The production of biodiesel from high free fatty acid mixed crude palm oil using a two-stage process was investigated. The kinetics of the reactions was determined in a batch reactor at various reaction temperatures. It was found that the optimum conditions for reducing high free fatty acid (FFA) in MCPO (8-12 wt.%/wt oil) using esterification was a 10:1 molar ratio of methanol to FFA and using 10 wt.%/wt of sulfuric acid (based on FFA) as catalyst. The subsequent transesterification reaction to convert triglycerides to the methyl ester was found to be optimal using 6:1 molar ratio of methanol to the triglyceride (TG) in MCPO and using 0.6 wt.%/volTG sodium hydroxide as catalyst. Both reactions were carried out in a stirred batch reactor over a period of 20 min at 55, 60 and 65 °C. The concentration of compounds in each sample was analyzed by Thin Layer Chromatography/Flame Ionization Detector (TLC/FID), Karl Fischer, and titration techniques. The results were used for calculating the rate coefficients by using the curve-fitting tool of MATLAB. Optimal reaction rate coefficients for the forward and reverse esterification reactions of FFA were 1.340 and 0.682 l mol−1 min−1, respectively. The corresponding optimal transesterification, rate coefficients for the forward reactions of TG, diglyceride (DG), and monoglyceride (MG) of transesterification were 2.600, 1.186, and 2.303 l mol−1 min−1, and for the reverse reactions were 0.248, 0.227, and 0.022 l mol−1 min−1, respectively.  相似文献   

4.
《分离科学与技术》2012,47(14):2167-2173
It has been reported that a basic aqueous solution was effective in extracting short chain C2–C6 fatty acids from noncatalytically cracked triacylglyceride oils. However, the extraction efficiency was not optimal over the entire range (C2–C12) of acids present in the cracking reactor organic liquid product (OLP). Therefore, an additional study was performed to explore the efficiency of solvent extraction using aqueous amines for this application. Based on the screening of several amines, two tertiary amines, trimethyl amine (TMA), and dimethyl ethanolamine (DMEA), were selected and evaluated. The extraction conditions were optimized with respect to several factors: temperature, amine concentration, and the amine-to-OLPratio (amine/OLP). Under optimal conditions, both TMA and DMEA were effective in extracting a wide range of organic acids, with TMA removing 93% of total acids and DMEA removing 100% of total acids. The amine/OLP was found to be a significant factor, as was the concentration of the amine solution. Temperature was not found to be a significant factor over the range studied. These results provide a basis for the development of a scalable, continuous process to produce a variety of C2–C12 fatty acids from biological sources.  相似文献   

5.
Medium-chain triglycerides (MCT) that contain caprylic acid (C8:0) and capric acid (C10:0) have immense medicinal and nutritional importance. Coconut oil can be used as a starting raw material for the production of MCT. The process, based on the interchange reaction between triglycerides and methyl esters of medium-chain fatty acids by chemical catalyst (sodium methoxide) or lipase (Mucor miehei) catalyst, appears to be technically feasible. Coconut oils with 25–28.3% (w/w) and 22.1–25% (w/w) medium-chain fatty acids have been obtained by chemical and lipase-catalyzed interchange reactions. Coconut olein has also been modified with C8:0 and C10:0 fatty acids, individually as well as with their mixtures, by chemical and lipase-catalyzed interchange reactions. Coconut olein is a better raw material than coconut oil for production of mediumchain fatty acid-rich triglyceride products by both chemical and lipase-catalyzed processes.  相似文献   

6.
Nearly 200 olive oils produced in the Mediterranean basin, mainly in Greece, during 4 yr from 1993 to 1996, were studied by gas chromatography (GC) and on-line GC-isotope ratio mass spectrometry (GC-C-IRMS). The composition of the oils in the more abundant fatty acids (C16:0, C16:1, C18:0, C18:1, C18:2, and C18:3) was obtained by GC after transesterification of the triglycerides into methyl esters. Using the hyphenated GC-C-IRMS technique, the 13C contents of the three most abundant acids, C16:0, C18:1, and C18:2, were measured with satisfactory accuracy. The results, analyzed in terms of geographical, temporal, and botanical factors, provide new criteria for the authentication of olive oils.  相似文献   

7.
Microbial lipase-catalyzed hydrolysis, esterification, and alcoholysis reactions were carried out on acid oils of commerce such as coconut, soybean, mustard, sunflower, and rice bran for the purpose of making fatty acids and various monohydric alcohol esters of fatty acids of the acid oils. Neutral glycerides of the acid oils were hydrolyzed byCanadida cylindracea lipase almost completely within 48 h. Acid oils were converted into fatty acid esters of short- and long-chain alcohols like C4, C8, C10, C12, C16, and C18 in high yields by simultaneous esterification and alcoholysis reactions withMucor miehei lipase as catalyst. Acid oils of commerce can be utilized as raw materials in making fatty acids and fatty acid esters using lipase-catalyzed methodologies.  相似文献   

8.
The unesterified fatty acids (UFA) present in fats and oils are isolated cleanly and without the formation of detectable artifacts due to saponification. The lipid (≤0.5 g) dissolved in 5 ml of n-hexane is passed over a 300-mg bed of Celite impregnated with saturated, aqueous Na3PO4 so that the solution passes through the bed in 3–4 min. After the bed has been washed, the UFA are freed from their salts by pumping of HC1 vapor over the bed. The acids are eluted with CH2Cl2 and subsequently separated underivatized by gas liquid chromatography. The C10 through C18.3 acids are separated in <15 min. Recovery of the C10-C18∶0 and C18∶1, C18∶2 and C18∶3 acids added to fatty acid-free fats and oils in several concentrations was nearly 100%  相似文献   

9.
High belite cements may be an alternative to reduce CO2 emissions. Although CO2 emissions may be depleted up to 10%, unfortunately, the hydration reactivity of belite phases is slow which leads to low mechanical strengths at early ages. In order to enhance their hydraulic reactivity, the activation of these cements by doping with alkaline oxides has been proposed. Here, we have synthesised a laboratory belite clinker without activation (47 wt.% of β-C2S and 19 wt.% of αH′-C2S) and two alkaline oxide activated clinkers (one with 13 wt.% of β-C2S, 24 wt.% of αH′-C2S and 19 wt.% of α-C2S; and the second with 12 wt.% of β-C2S, 42 wt.% of αH′-C2S and 5 wt.% of α-C2S). We have also developed a methodology to analyse quantitatively the phase evolution of cement pastes and we have applied it to these high belite cements. Rietveld quantitative phase analysis of synchrotron X-ray powder diffraction data, together with chemical constraints, is used to determine the phase development up to 1 year of hydration in the belite cement pastes. β-C2S almost does not react during the first 3 months, meanwhile αH′-C2S reacts on average more than 50% in the same period. Moreover, the degree of reaction of α-C2S is slightly larger (on average about 70% after three months) than that of αH′-C2S. Full phase analyses are reported and discussed including the time evolution of amorphous phases and free water.  相似文献   

10.
Pyrolysis of an organic concentrate from municipal solid waste was carried out using a bench-scale fluidized bed reactor at 350-540 °C comparing Al2O3 with activated olivine sand as bed materials. A maximum oil yield of 50 wt.% was obtained using the activated olivine sand at 400 °C while only 45 wt.% was obtained at 500 °C using Al2O3. The bio-oils using activated olivine sand at 400 °C had an H/C ratio of 1.50 and O/C ratio of 0.37 and were less aromatic and less nitrogenous compare to the oils obtained using Al2O3 at 400 °C where the H/C ratio was 1.32 and the O/C ratio was 0.44. The aromatic compounds were found to be reduced while the aliphatic compounds increased in the oils generated using activated olivine sand. The calorific value of the bio-oil at 500 °C was 29 MJ/kg using activated olivine sand while the bio-oil using Al2O3 was 23 MJ/kg. The presence of iron, magnesium and other oxides probably promotes the removal of oxygen, which indicates that the activation energy of C―O bond breakage is reduced compared to the C―C bonds, thus promoting dehydration, decarboxylation and alkalation reactions to produce aliphatic fatty acid at lower temperatures.  相似文献   

11.
C.G. Soni  A.K. Dalai  T. Pugsley 《Fuel》2009,88(5):920-925
Gasification of meat and bone meal followed by thermal cracking of tar was carried out at atmospheric pressure using a two-stage fixed bed reaction system in series. The first stage was used for the gasification and the second stage was used for thermal cracking of tar. In this work, the effects of temperature (650-850 °C) of both stages, equivalence ratio (actual O2 supply/stoichiometric O2 required for complete combustion) (0.15-0.3) and the second stage packed bed height (40-100 mm) on the product (char, tar and gas) yield and gas (H2, CO, CO2, CH4, C2H4, C2H6, C3H6, C3H8) composition were studied. It was observed that the two-stage process increased hydrogen production from 7.3 to 22.3 vol.% (N2 free basis) and gas yield from 30.8 to 54.6 wt.% compared to single stage. Temperature and equivalence ratio had significant effects on the hydrogen production and product distribution. It was observed that higher gasification (850 °C) and cracking (850 °C) reaction temperatures were favorable for higher gas yield of 52.2 wt.% at packed bed height of 60 mm and equivalence ratio of 0.2. The residence time of tar and product gases was varied by varying the packed bed height of second stage. The tar yield decreased from 18.6 wt.% to 14.2 wt.% and that of gas increased from 50.6 wt.% to 54.6 wt.% by changing the packed bed height of second stage from 40 to 100 mm while the gross heating value (GHV) of the product gas remained almost constant (16.2-16.5 MJ/m3).  相似文献   

12.
The effect of the composition of zeolite containing catalyst, the conditions of conducting the process, and the nature of oils on the distribution of target products during conversion under conditions of catalytic cracking is studied. The study is performed on bizeolite catalysts containing zeolites (ultrastable Y and ZSM-5 at different ratios) and on catalyst LUX containing18 wt % of zeolite Y in the HREY form. It is shown that the presence of zeolite ZSM-5 in the catalyst composition promotes the formation of olefines C2–C4. An increase in the severity of cracking process (elevated temperatures and catalyst: raw material ratios) improves the yield of gaseous products and coke with a simultaneous reduction in the yield of the gasoline fraction. The effect the nature of vegetable oils has is studied using the examples of palm, rapeseed, mustard, and sunflower oils. It is demonstrated that for the maximum yield of olefines C2–C4 and gasoline, we must use oils with elevated contents of saturated fatty acids. The regularities of the simultaneous cracking of sunflower oil and vacuum gas oil are studied. It is been found that upon simultaneous cracking, the total conversion of the mixed feedstock and yield of gasoline fraction increase; the maximum effect is attained with the addition of 3–10 wt % of vegetable oil.  相似文献   

13.
Proximate analysis of the seeds from three commercial melon cultivars (Honey Dew, Hy‐mark and Orange Flesh) showed high percentage of lipids (25.7—27.6%) and proteins (15.2—19.2%). The physico‐chemical properties of the hexane‐extracted oil from the seeds of these cultivars were determined. Gas chromatographic analysis of the oils showed the presence of almost all fatty acids starting from C6— C24 except that of C11 , C21 C23 , C18:2 being the principal fatty acid followed by C18:1 , C16:0 , and C18:0 fatty acids. The number of fatty acids, which were present in concentrations higher than 0.01% of total fatty acids, was 17, 14, and 13, respectively, in these cultivars  相似文献   

14.
Competitive adsorption of free fatty acids and carotenoids adsorption from sesame oil miscellas on vegetable carbon was studied by regression analysis. The equations obtained indicated that unsaturated carbonyls, free fatty acids (FFA0), and carotenoids interacted to determine fatty acid and carotenoid adsorption. The driving force for carotenoid adsorption, the carotenoid concentration (C0), was affected by a quadratic function of free fatty acid concentration [i.e., (FFA0/C0)2]. As FFA0/C0 increased, carotenoid adsorption efficiency was reduced, possibly because the accessible adsorption sites for carotenoids were occupied by fatty acids. Unsaturated carbonyls promoted free fatty acid adsorption, probably in the pores that were readily accessible for fatty acids. However, when the carbonyl concentration increased in the oil miscella, carbonyls were adsorbed instead of fatty acids. The results indicated how different oil molecules interact and affect adsorption (i.e., free fatty acids and carotenoids). Therefore, the adsorption process of vegetable oils (i.e., bleaching) has to be considered a multicomponent adsorption system.  相似文献   

15.
Esters of fatty acids, derived from vegetable oils or animal fats, and known as biodiesel, are a promising alternative diesel fuel regarding the limited resources of fossil fuels and the environmental concerns. In this work, methanolysis of soybean oil was investigated using Mg-Al hydrotalcites as heterogeneous catalyst, evaluating the effect of Mg/Al ratio on the basicity and catalytic activity for biodiesel production. The catalysts were prepared with Al/(Mg + Al) molar ratios of 0.20, 0.25 and 0.33, and characterized by X-ray diffraction (XRD), textural analysis (BET method) and temperature-programmed desorption of CO2 (CO2-TPD). When the reaction was carried out at 230 °C with a methanol:soybean oil molar ratio of 13:1, a reaction time of 1 h and a catalyst loading of 5 wt.%, the oil conversion was 90% for the sample with Al/(Mg + Al) ratio of 0.33. This sample was the only one to show basic sites of medium strength. We also investigated the reuse of this catalyst, the effect of calcination temperature and made a comparison between refined and acidic oil.  相似文献   

16.
Extraction, fractionation, and gas chromatography−mass spectrometry analyses guided by bioassays have shown that n-alkanes and free fatty acids in leaf epicuticular wax of the Japanese knotweed Fallopia (Reynoutria) japonica stimulate oviposition in the Far-Eastern knotweed borer, Ostrinia latipennis (Lepidoptera: Crambidae). n-Alkanes made up 48.1% of the total amount of epicuticular wax, and their carbon chain length was in the C16−C33 range, with n-nonacosane (n-C29) most abundant, followed by n-C27, n-C25, and n-C31. Free fatty acids with C9−C22 accounted for 22.3%, and hexadecanoic acid was predominant. A mixture of authentic n-alkanes and fatty acids of the composition found in the epicuticular wax, a mixture of n-alkanes, and a mixture of fatty acids significantly enhanced oviposition. Thus, it was demonstrated that both n-alkanes and free fatty acids in leaf epicuticular wax of F. japonica are naturally occurring oviposition stimulants for O. latipennis.  相似文献   

17.
Steam pyrolysis experiments were performed on immature samples from the Irati oil shale, Paraná Basin, Brazil, using a maximum temperature of 350 °C with up to 98 h exposure time at that temperature. The objectives were to study geochemical and petrographical changes in the source material during stepwise increase in maturity, in steam conditions, comparing the properties of expelled oil with the bitumen retained in the solid residue after experimentation.Petrographical and geochemical parameters such as vitrinite reflectance and Tmax, indicated an increase in maturity related to the exposure time of the organic matter to the maximum temperature. However, biomarker ratios such as 22S/(22S + 22R) C31 and C32 homohopanes, 20S/(20S + 20R) and αββ/(αββ + ααα) C29 sterane, which are considered to be indicators of organic matter maturity levels, did not reach their equilibrium values. Some biomarkers frequently used as indicators of specific sources and/or paleoenvironments of deposition such as hopane/sterane ratio, and the concentrations of C27 and C29 steranes showed significant variations related to the stage of maturity. Based on the evaluation of Rock-Eval parameters, the transformation ratios in steam pyrolysis conditions reached levels higher than 80% in samples having 9 and more hours of exposure time to maximum temperature. Bitumen was found to be enriched in components of heavier molecular weight (resins and asphaltenes), whereas the expelled oils contained higher quantities of aliphatic and aromatic components. At relatively low maturity levels the n-alkane distribution of expelled oils indicate a somewhat higher maturity level when compared to the n-alkane distribution of the bitumen retained in the source rock, whereas at higher maturity levels the n-alkane distribution for the expelled oil and for the bitumen is very similar.  相似文献   

18.
A gasoline distillate from the Fischer-Tropsch synthesis (so-called as F-T gasoline) was collected in a cold trap set in a gas-flowed slurry reaction system. The F-T gasoline contained 92.8 wt.% n-alkanes (ranged from n-C4H10 to n-C14H30), 2.4 wt.% 1-alkenes, and 4.8 wt.% iso-alkanes. By the hydroisomerization-cracking in an atmospheric flowed fixed-bed reactor over the catalysts containing Pt and heteropoly compound Cs2.5H0.5PW12O40 (abbreviated as Cs2.5), the F-T gasoline was converted to gasoline distillated mixed alkanes with a high iso/n ratio. A mechanical mixture of Pt/Al2O3 and Cs2.5 (noted as Pt/Al2O3 + Cs2.5) showed the highest catalytic performance among various catalysts. The product over Pt/Al2O3 + Cs2.5 after 5 h on-steam at 523 K contained 94.4% C5-C9 (gasoline components) with a high iso/n ratio of 8.45. The co-grinding time of Pt/Al2O3 and Cs2.5 influenced the catalytic performance when the time was shorter than 10 min but gave little influence on the catalytic performance when the time was longer than 10 min. Because the iso/n ratio of products over Pt/Al2O3 + Cs2.5 increased by adding Pt in Cs2.5 and decreased with increasing H2/feedstock, the reaction proceeded through a bifunctional mechanism in which Pt sites achieved a hydrogenation/dehydrogenation function and acid sites achieved an isomerization/cracking function. The balance of Pt and solid acids was important to obtain a high catalytic performance in the hydroisomerization-cracking of F-T gasoline. Because Cs2.5 possessed moderate acidic strength and uniformly distributed acidic sites, Pt/Al2O3 + Cs2.5 showed a higher catalytic stability than that over Pt/Al2O3 + SO4/ZO2 and showed a higher catalytic activity than that over Pt/Al2O3 + H-ZSM-5.  相似文献   

19.
Milk lipids were fractionated by silicic acid column chromatography and preparative thinlayer chromatography (TLC). Ceramide monohexoside (CMH), ceramide dihexoside (CDH), phosphatidyl ethanolamine (PE), phosphatidyl choline (PC), phosphatidyl serine (PS), and sphingomyelin (Sph) were isolated, and the purity of each was checked by infrared spectroscopy and TLC. The diacylphospholipids were hydrolyzed with phospholipase A and the products separated by TLC. Fatty acid methyl esters were prepared from the various fractions and analyzed by gas chromatography. The glycolipids, CMH and CDH, and Sph contained large amounts of long-chain saturated fatty acids, especially C22:0, C23:0, and C24:0, PE, PS, and PC contained C10-C22 normal and branched-chain saturated fatty acids, and C15-C20 unsaturated fatty acids (mainly monoenes). The distributions of saturated acids between the α′- and β-positions were respectively: PE, 46 and 11%; PS, 65 and 19%; and PC, 72 and 53%. PC was exceptional in that there was 10.8% myristic acid in the β-position and only 5.6% in the α′-position. PE and PS were similar in composition except that in PE oleic acid was evenly distributed, and in PS was largely in the β-position. In general, PC was much more saturated than PE or PS, and there was no overall pattern governing the specific distribution of the fatty acids in the three diacylphospholipids. Comparison with PC from other bovine tissues and from egg lecithin showed that fatty acids are located much less specifically in milk phospholipids than in PC from other sources. Presented at the AOCS Meeting, Houston, Texas, April, 1965.  相似文献   

20.
Biofuel production from vegetable oil is potentially a good alternative to conventional fossil derived fuels. Moreover, liquid biofuel offers many environmental benefits since it is free from nitrogen and sulfur compounds. Biofuel can be obtained from biomass (e.g. pyrolysis, gasification) and agricultural sources such as vegetable oil, vegetable oil sludge, rubber seed oil, and soybean oil. One of the most promising sources of biofuel is vegetable oil sludge. This waste is a major byproduct of vegetable oil factories. It consists of triglycerides (61%), free fatty acid (37%) and impurities (2%). The hydrocarbon chains of triglycerides and free fatty acid are mainly made up of C16 (30%) and C18 (36%) hydrocarbons. The others consist of C12-C17 hydrocarbon chains. Transesterification can help in converting vegetable oil sludge into biofuel. The disadvantage of this method is that a large amount of methanol is required. The alternative method for this conversion is catalytic cracking. The objective of this research is to evaluate and compare the pyrolysis process with cracking catalytic reaction of vegetable oil sludge by Micro-activity test MAT 5000 of Zeton-Canada.A ZSM-5/MCM-41 multiporous composite (MC-ZSM-5/MCM-41), was successfully synthesized using silica source extracted from rice husk. The material has the MCM-41 mesoporous structure, and its wall is constructed by ZSM-5 nanozeolite crystals. The porous system of the material includes pores of the following sizes: 5 Å (ZSM-5 zeolite), 40 Å (MCM-41 mesoporous material), and another porous system whose diameter is in the range of 100-500 Å (mesoporous system) formed by the burning of organic compounds that remain in the material during the calcination process. This pore system contributes to an increase in the catalytic performance of synthesized material.The results of vegetable oil sludge cracking reaction show that the product consists of fractions such as dry gas, liquefied petroleum gas (LPG), gasoline, light cycle oil (LCO), and (heavy cycle oil) HCO, which are similar to those of petroleum cracking process.MC-ZSM-5/MCM-41 catalyst is efficient in the catalytic cracking reaction of vegetable oil sludge as it has higher conversion and selectivity for LPG and gasoline products in comparison to the pyrolysis process. Product distribution (% of oil feed) of cracking reaction over MC-ZSM-5/MCM-41 is coke (3.4), total dry gas (7.0), LPG (31.1), gasoline (42.4), LCO (8.9), HCO (7.2); and that of pyrolysis are coke (19.0), total dry gas (9.3), LPG (16.9), gasoline (28.8), LCO (13.7), and HCO (12.3).These results have indicated a new way to use agricultural waste such as rice husk for the production of promising catalysts and the processing of vegetable oil sludge to obtain biofuel.  相似文献   

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