共查询到20条相似文献,搜索用时 0 毫秒
1.
HZSM-5分子筛可用于脂肪酸酯催化转化生产芳烃、低碳烯烃等过程。未经过处理的HZSM-5分子筛芳烃产率较低,使用过渡金属改性后的HZSM-5分子筛酸性质发生了改变,能够提高芳烃的收率。以等体积浸渍法对HZSM-5分子筛进行改性,制备了不同锌含量的 Zn/HZSM-5分子筛,并进行了 XRD、XRF、XPS、NH3-TPD、SEM、TEM、Py-IR、N2物理吸附-脱附等多种表征,结果表明锌的引入没有改变 HZSM-5的晶体结构,锌物种能均匀分布在 HZSM-5分子筛表面及孔道。棕榈油催化转化实验结果显示Zn含量(质量分数)为3% 的 Zn/HZSM-5有最好的催化效果,芳烃在液相烃类所占比例(质量分数)为87.92%,芳烃收率(质量分数)为59.44%。 相似文献
2.
The catalytic conversion of canola oil to fuels and chemicals was studied over HZSM-5, H-mordenite, H-Y, silicalite, aluminum-pillared clay (AL-PILC) and silica-alumina catalysts in a fixed bed micro-reactor. The reactor was operated at atmospheric pressure, a temperature range of 375?500°C and weight hourly space velocity (WHSV) of 1.8 and 3.6 h?1. An organic liquid product (OLP), light hydrocarbon gases and water were the major products. The objective was to maximize the amount of OLP and its hydrocarbon content as well as optimize the selectivity for gas phase olefinic hydrocarbons. In addition, the performance of each catalyst in terms of minimizing the coke formation was examined. Among the six catalysts, HZSM-5 gave the highest amount of OLP of 63 mass% at 1.8 WHSV and 400°C. The hydrocarbon content of this OLP product was 83.8 mass%. With the exception of silica-alumina and aluminum-pillared clay catalysts, the other catalysts gave high concentrations of aromatic hydrocarbons which ranged between 23.1–95.6 mass% of OLP. The gas products consisted mostly C3 and C4 hydrocarbons. Ethylene, propylene and butanes were some of the valuable hydrocarbon gases. The olefin/paraffin ratio of the gas products was highest for AL-PILC catalysts but it never exceeded unity. The results showed that it was possible to significantly alter the yield and selectivity for the different hydrocarbon products by using different catalysts or changing the catalyst functionality such as acidity, pore size and crystallinity. Reaction pathways based on these results are proposed for the conversion of canola oil 相似文献
3.
Performance studies of various cracking catalysts in the conversion of canola oil to fuels and chemicals in a fluidized-bed reactor 总被引:4,自引:0,他引:4
Sai P. R. Katikaneni John D. Adjaye Raphael O. Idem Narendra N. Bakhshi 《Journal of the American Oil Chemists' Society》1998,75(3):381-391
Studies were conducted at atmospheric pressure at temperatures in the range of 400–500°C and fluidizing gas velocities in
the range of 0.37–0.58 m/min (at standard temperature and pressure) to evaluate the performance of various cracking catalysts
for canola oil conversion in a fluidized-bed reactor. Results show that canola oil conversions were high (in the range of
78–98 wt%) and increased with an increase in both temperature and catalyst acid site density and with a decrease in fluidizing
gas velocity. The product distribution mostly consisted of hydrocarbon gases in the C1–C5 range, a mixture of aromatic and aliphatic hydrocarbons in the organic liquid product (OLP) and coke. The yields of C4 hydrocarbons, aromatic hydrocarbons and C2–C4 olefins increased with both temperature and catalyst acid site density but decreased with an increase in fluidizing gas velocity.
In contrast, the yields of aliphatic and C5 hydrocarbons followed trends completely opposite to those of C2–C4 olefins and aromatic hydrocarbons. A comparison of performance of the catalysts in a fluidized-bed reactor with earlier work
in a fixed-bed reactor showed that selectivities for formation of both C5 and iso-C4 hydrocarbons in a fluidized-bed reactor were extremely high (maximum of 68.7 and 18 wt% of the gas product) as compared to
maximum selectivities of 18 and 16 wt% of the gas product, respectively, in the fixed-bed reactor. Also, selectivity for formation
of gas products was higher for runs with the fluidized-bed reactor than for those with the fixed-bed reactor, whereas the
selectivity for OLP was higher with the fixed-bed reactor. Furthermore, both temperature and catalyst determined whether the
fractions of aromatic hydrocarbons in the OLP were higher in the fluidized-bed or fixed-bed reactor. 相似文献
4.
The upgrading of crude tall oil (CTO) to fuels and chemicals was studied at atmospheric pressure and in the temperature range 370 to 440°C in a fixed bed microreactor containing HZSM-5. The oil was co-fed with diluents such as tetralin, methanol and steam. High oil conversions of the order of 80–90 wt. % were obtained using tetralin and methanol as diluents but with steam the conversion only ranged between 36 to 70 wt. %. The maximum concentration of gasoline range aromatic hydrocarbons in the liquid product was 52 and 57 wt. % with tetralin and steam but only 39 wt. % with methanol. The amount of gas product in most of the runs was 1–4 wt.%. A reaction scheme is postulated based on the results. 相似文献
5.
The color of refined palm oil and palm oil products is conventionally measured using the manually operated Lovibond® Tintometer. In the present study, one manual/visual and three automatic colorimeters for the measurement of vegetable oil color were used for color measurements of refined palm oil. All colorimeters used were commercially available instruments except for an automatic palm oil colorimeter developed specifically for the measurement of palm oil color. The color values obtained from all four instruments were compared using the visually obtained readings as reference values. Results showed that all three automatic instruments gave correlation coefficients of greater than 0.9300 for red color measurements. In addition, the Student t-test showed no difference between the analysis of red color using the visual method and the palm oil colorimeter. This investigation concludes that, although it is extremely difficult to reduce the lack of precision in color measurement of palm oil, a properly designed and calibrated automatic instrument may still be the better choice because reproducibility and repeatability are required in all standard test methods. The palm oil colorimeter offers a ready and relatively inexpensive solution to the problem of color matches based on visual observations. 相似文献
6.
液体燃料广泛应用于交通、物流和生活等行业,然而液体燃料的生产严重依赖石油。我国石油资源相对贫乏,石油对外依存度高达60%。为减少对石油的依赖,我国正积极开发石油替代资源,特别是油页岩和煤炭。但迄今少有文献报道对油页岩与煤路线生产液体燃料过程进行全面的技术经济分析和比较。本文通过对油页岩制油和煤制油分别进行建模和模拟,根据模拟从能效、投资和成本等方面对这两种路线进行分析和比较。结果表明油页岩制油的能效比煤制油低5个百分点,因为油页岩制油的原料利用率低,产品收率低。经济方面,油页岩制油的固定投资为63.34元/GJ,相比煤制油节省70%,因为油页岩制油流程短,设备结构简单。但油页岩制油的原料消耗大,生产1t液体燃料消耗24.5t油页岩,所以其成本相比煤制油仅节省6%。 相似文献
7.
Robiah Yunus Ahmadun Fakhru'l‐Razi Tian Lye Ooi Sunny E. Iyuke Joseph M. Perez 《European Journal of Lipid Science and Technology》2004,106(1):52-60
Due to the global drive towards biodegradable products, trimethylolpropane [2‐ethyl‐2‐(hydroxymethyl)‐1, 3‐propanediol] (TMP) esters based on palm and palm kernel oils were synthesized, their lubrication properties evaluated, and their potential as base stock for biodegradable lubricants assessed. Two types of TMP esters were considered: palm kernel (PKOTE) and palm oil (PPOTE) TMP esters, derived from palm oil and palm kernel methyl esters, respectively. Lubrication properties such as viscosity, viscosity index (VI) and pour point (PP) were determined according to methods of the American Society for Testing and Materials. Wear and friction properties were evaluated using a four‐ball test machine, while oxidative stability was studied with the Penn State Micro‐oxidation thin‐film test. High VI ranges between 170 to 200 were recorded for these base stocks. PP were relatively high, between 4 to —1 °C, but were improved to at least —33 °C in high oleic palm oil TMP esters. The effects of chemical structure and impurities on wear properties and oxidative stability were also studied. The presence of methyl esters was found to improve wear, but hydroxyl groups in mono‐ and diesters had negative effects at high concentrations. Differences in chemical structures of PKOTE and PPOTE were shown to affect friction and wear results. Both base fluids exhibit oxidative stability comparable to other high oleic base fluids. 相似文献
8.
B. S. Jalani S. C. Cheah N. Rajanaidu A. Darus 《Journal of the American Oil Chemists' Society》1997,74(11):1451-1455
The oil palm Elaeis guineensis is the highest oil-yielding crop and has the potential to become the major supplier of both edible oil and renewable industrial
feedstock. The oil yield from wild groves is presently less than 0.5 t/ha/y. However, through breeding and selection, the
oil yield of commercial plantations could reach as much as 8 t/ha/y. New planting materials also have the capability of better
oil yields with high iodine value (IV), slow height increment, and larger kernels. The oil also contains considerable amounts
of carotenoids (500–700 ppm), vitamin E (600–1000 ppm), and sterols (250–620 ppm). The oil yield of another oil palm species,
E. oleifera, is approximately 0.5 t/ha/y with high contents of carotenoids (700–1500 ppm), vitamin E (700–1500 ppm), and sterols (3500–4000
ppm). The above traits could be improved through breeding and biotechnology. Biotechnological efforts at the Palm Oil Institute
of Malaysia are directed toward the production of oil with high IV and high monounsaturated fatty acids for edible purposes
and industrial uses. Isolation and manipulation of the genes involved in the biosynthesis of fatty acids are the main focus.
The aim is to increase the efficiency of conversion of palmitate (C16:0) to oleate (C18:1). Levels of palmitate and oleate are controlled by the enzymes acyl-acyl carrier protein (ACP) thioesterase and β-keto acyl
ACP synthase II. The chain termination reactions of C16:0 and C18:1 are independent, thus paving the way for the possibility of reducing palmitate levels by switching off the palmitoyl ACP
thioesterase gene.
Paper presented at the 88th AOCS Annual Meeting & Expo. May 11–14, 1997, Seattle, Washington, USA. 相似文献
9.
10.
Badrul Hisyam Zainudin Nor Kartini Abu Bakar Halimah Muhamad 《European Journal of Lipid Science and Technology》2009,111(10):1014-1019
In this study, a new method was developed for the determination of cypermethrin residue in both crude palm oil (CPO) and crude palm kernel oil (CPKO) using GC with electron capture detector. In this method, the oil was extracted with acetonitrile. Aliquots were cleaned‐up using combined solid phase extraction (SPE), and a primary‐secondary amine in combination with graphitized carbon black. The SPE cartridges were first conditioned and then eluted with acetonitrile. Cypermethrin recoveries from the fortified CPO samples were 87–98% with relative standard deviation (RSD) values of 4–8%, while those for the fortified CPKO samples were 83–100% with RSD values of 3–10%. Since good recoveries were obtained with RSD values below 10% in most cases, the proposed methodology will be useful for the analyses of palm oil samples. The method was successfully applied to the analysis of cypermethrin in real palm oil samples from various parts of Malaysia. No cypermethrin residue was found among 30 samples analyzed. 相似文献
11.
Catalytic conversion of methane to more useful chemicals and fuels: a challenge for the 21st century 总被引:11,自引:0,他引:11
The very large reserves of methane, which often are found in remote regions, could serve as a feedstock for the production of chemicals and as a source of energy well into the 21st century. Although methane currently is being used in such important applications as the heating of homes and the generation of hydrogen for ammonia synthesis, its potential for the production of ethylene or liquid hydrocarbon fuels has not been fully realized. A number of strategies are being explored at levels that range from fundamental science to engineering technology. These include: (a) stream and carbon dioxide reforming or partial oxidation of methane to form carbon monoxide and hydrogen, followed by Fischer–Tropsch chemistry, (b) the direct oxidation of methane to methanol and formaldehyde, (c) oxidative coupling of methane to ethylene, and (d) direct conversion to aromatics and hydrogen in the absence of oxygen. Each alternative has its own set of limitations; however, economical separation is common to all with the most important issues being the separation of oxygen from air and the separation of hydrogen or hydrocarbons from dilute product streams. Extensive utilization of methane for the production of fuels and chemicals appears to be near, but current economic uncertainties limit the amount of research activity and the implementation of emerging technologies. 相似文献
12.
Canola oil conversion was studied at atmospheric pressure over Pt/HZSM-5 catalyst (0.5 mass% Pt) in a fixed bed micro-reactor. The operating conditions were: temperature range of 400?500°C, weight hourly space velocity (WHSV) of 1.8 and 3.6 h?1 and steam/oil ratio of 4. The objective was to optimize the amount of gasoline range hydrocarbons in the organic liquid product (OLP) and the selectivity towards olefins and isohydrocarbons in the gas product. The gas yields varied between 22–65 mass% and were higher in the presence of steam compared to the operation without steam. The olefin/paraffin mass ratio of C2-C4 hydrocarbon gases varied between 0.31–0.79. The isohydrocarbons/n-hydrocarbons ratio was higher with Pt/HZSM-5 (1.6–4.8) compared with pure HZSM-5 catalyst (0.2–1.0). The OLP yields with Pt/HZSM-5 (20–55 mass% of canola oil) were slightly lower compared to HZSM-5 (40–63 mass% of canola oil) under similar conditions. The major components of OLP were aliphatic and aromatic hydrocarbons. A scheme postulating the reaction pathways for the conversion of canola oil over Pt/HZSM-5 catalyst is also presented. 相似文献
13.
G. N. Da Rocha Filho M. H. S. Bentes D. Brodzki G. Djéga-Mariadassou 《Journal of the American Oil Chemists' Society》1992,69(3):266-271
Catalytic hydrocracking ofHevea brasiliensis (Seringa) andVirola sebifera (Ucuuba) oils was carried out in the presence of a NiMo/Al2O3 catalyst sulfidizedin situ with elemental sulfur at 360°C. The initial pressure of hydrogen was 140 bars. Conversions of nearly 100% of the vegetable
oils were achieved. The compositions of the liquid fuels were studied in detail by gas chromatography/mass spectrometry. The
main products were found to be alkanes, cycloalkanes, aromatics and carboxylic acids. 相似文献
14.
F. B. H. Ahmad S. Hamdan M. A. Yarmo A. Alimunir 《Journal of the American Oil Chemists' Society》1995,72(6):757-758
The co-metathesis reaction of crude palm oil with ethene in the presence of WCL6/Me4Sn, followed by termination of this reaction with methanol, gives terminal alkenes. The major metathesis products are 1-decene
and methyl 9-decenoate. 相似文献
15.
Temperature effect on the viscosities of palm oil and coconut oil blended with diesel oil 总被引:1,自引:0,他引:1
One of the major difficulties in using crude vegetable oils as substitute fuels in diesel engines is their relatively high
viscosities. Increasing the temperature of the crude vegetable oil, blending it with diesel oil, or the combination of both
offers a simple and effective means of controlling and lowering the viscosities of vegetable oils. This work reports viscosity
data, determined with a rotational bob-and-cup viscometer, for crude palm oil and cononut oil blended with diesel oil over
the temperature range of 20–80°C and for different mixture compositions. All the test oil samples showed a time-independent
newtonian type of flow behavior. The reduction of viscosity with increasing liquid temperature followed an exponential relationship,
with the two constants of the equation being a function of the volume percentage of the vegetable oil in the mixture. A single
empirical equation was developed for predicting the viscosity of these fuel mixtures under varying temperatures and blend
compositions. 相似文献
16.
This paper provides a review of the catalytic upgrading of biomass-derived oils such as wood pyrolytic oils, plant/vegetable oils and tall oil to transportation fuels and useful chemicals. Both zeolite and hydrotreating type catalysts have been found suitable for upgrading which was usually done in fixed bed reactors. The hydrotreatment of pyrolytic oils at 250-450°C and 15-20 MPa H2 pressures has been reported to yield up to 55 wt. % of liquid product containing 40-50 wt. % of gasoline range hydrocarbons. In the case of HZSM-5, the upgrading has been carried out at atmospheric pressure and 350-500°C and over 85 wt. % conversions of plant oils and tall oil have been achieved under optimum conditions. Liquid product yields from these oils were up to 70 wt. % of feed which contained 40-50 wt. % aromatic hydrocarbons. With the high pressure pyrolytic oil, pitch conversions of over 75 wt. % have been observed with HZSM-5 using co-feeds such as tetralin. However, there is only scant information available on the kinetic and mechanistic aspects of upgrading of these oils. 相似文献
17.
The upgrading of bio-oil, obtained by fast pyrolysis of maple wood, was studied over HZSM-5 in a fixed bed micro-reactor operated at atmospheric pressure and in the temperature range 330-425°C. The objective of upgrading was to maximize the amount of organic distillate product with a high yield of aromatic hydrocarbons. A maximum organic distillate of 38 wt.% of bio-oil, which represented 28.6 wt.% of wood, was obtained at 370°C. The yield of aromatic hydrocarbons was 19.9 wt.% of wood. Above 400°C, nearly 50 wt.% of the bio-oil was converted to coke and char. The conversion of non-volatile components of the bio-oil (pitch) to volatiles was at a maximum of 68 wt. % at 370°C. However, when the bio-oil was co-processed with tetralin, the maximum conversion of non-volatiles increased to 86 wt.% at 410°C and the amounts of coke and char decreased. The yield of aromatic hydrocarbons also decreased to a maximum of 10.3 wt. % of wood. The role of tetralin was mainly as a diluent and not as a hydrogen donor solvent. 相似文献
18.
19.