餐饮废油酯交换制备生物柴油的试验研究

生物柴油是清洁可再生能源,已受到世界各国越来越多的关注。为此,以上海交通大学食堂的餐饮废油为原料,以自制的SO42-/ZrO2-Al2O3固体超强酸作为催化剂,在试验室规模的反应装置中,采用酯交换法进行了餐饮废油酯交换制备生物柴油的试验研究。结果表明,收集的餐饮废油适合作为生产生物柴油的原料,在醇油摩尔比6:1、催化剂含量1%、反应温度70℃和反应时间2h的条件下,生物柴油转化率达到78%。生物柴油的密度、灰分、运动粘度和凝点的指标符合我国国标0号柴油质量标准。     

大豆油酯交换制备生物柴油的实验研究

以大豆油为原料,研究在KOH催化剂作用下与甲醇进行酯交换反应制备生物柴油的工艺,考察了甲醇用量、催化剂用量、反应温度和反应时间等操作条件对反应的影响.结果表明,该反应最适宜的操作条件为:甲醇用量为大豆油质量的20%,催化剂用量为大豆油质量的1.2%,反应温度为60℃,反应时间为120min;大豆油制备的生物柴油品质达到我国GB/T 20828-2007、美国ASTM和德国DINE生物柴油标准,其生物柴油的转化率为96.79%.     

我国小桐子生物柴油产业现状和发展探讨

生物柴油是清洁的可再生能源,受到世界各国的高度重视,也是我国未来较长时期内石油市场发展的焦点。小桐子制取生物柴油可行性高,将其形成产业化对于解决我国能源安全、改善生态环境、增加农民收入具有重要意义。     

NaHSO4催化椰子油皂脚油酯化降酸工艺优化

以椰子油皂脚油为原料的生物柴油酯化效率与催化剂和结合反应装置的操作方法有关。以硫酸氢钠为催化剂结合设计的反应装置,对高酸值椰子油皂脚油进行预酯化反应研究。通过单因子试验探讨适用于反应装置的反应条件,并讨论不同的操作方式对反应速率和反应进程的影响。结果表明:最佳条件为:反应温度105℃,甲醇通入流速为0.825 mL/min,催化剂用量为5.0%,反应2 h下转化率>95%。催化剂重复使用9次后转化率78.15%;改变操作方法,0.1 MPa条件下反应,采用通入甲醇1.32 mL/min反应30 min,后常压条件下通入甲醇量0.825 mL/min,反应30 min,椰子油皂脚油酸值由106变为1.2 mg/g,转化率98.9%,并可缩短酯化时间1 h,油脂成品满足酯交换工序要求。精制的生物柴油成品所测试的技术指标符合德国现行生物柴油标准(DIN V 51606)。     

Photosynthesis,fluorescence and mesophyll conductance responses to increasing salinity levels in Jatropha curcas at early vegetative stages

Salinity is often a great limitation in marginal environments with potential for developing alternative non-edible crops for biodiesel, and the physiological responses involved in the recovery of plants subjected to high salinity are poorly studied. The aim of this study on Jatropha curcas is to identify salinity tolerance responses of net photosynthesis rate under saturating irradiances (A_max), its recovery capacity and the role of mesophyll conductance (g_m) over A_max. Two experiments were performed with seedlings in pots under outdoor conditions and hydroponic conditions, respectively, with salinity intensities ranging from 3 to 12 dS/m, their isosmotic treatments with polyethylene glycol (PEG) and controls without abiotic stress. A_max and growth rate were mainly affected by salinity effects in all the ranges, with a drastic 60% drop in dry biomass under 6 dS/m, revealing a significant sensitivity of this species. However, a surprising increase in A_max was promoted by the presence of NaCl, with respect to their respective isosmotic treatments with PEG, although it was still lower than the unstressed plants. This advantage disappeared from 9 dS/m, but negative effects of NaCl toxicities were never detected. The photochemical apparatus resulted extremely resistant in this species, since Fv/Fm and leaf greenness were affected only at 12 dS/m. So, g_m was strongly and linearly associated with A_max. This association derives from the overall range of stress intensities tested, thus appearing as the main useful trait for enhancing photosynthesis depletion under salinity stress, without losses of the water use efficiency. A drastic 75% drop was also detected in the electron use for photosynthesis, revealing that A_max would also be modulated by metabolic impairments under salinity. Moreover, full recovery after only 8 days was observed, confirming the high resistance of the species to NaCl stress even under very high salinities. This study contributes to a better understanding of the physiological processes involved in the response of J. curcas to salinity during early vegetative stage, generating possibilities for improving tolerance of this species under environments exposed to salinity.     

热带木本生物质能源树种——油棕

油棕是一种重要的热带木本生物质能源树种,具有结果期长、产量和含油量高等特点。随着原油价格的不断上涨,生物柴油的发展日益受到关注。而棕榈油由于生产成本低廉,成为生产生物柴油最具竞争力的原料。本文分别综述了油棕的基本特性、全球及我国棕榈油生产贸易和消费状况、我国发展油棕产业的重要意义,在此基础上对我国发展油棕产业的可行性和前景进行了探讨。     

The energy value of biodiesel glycerine products fed to broilers at different ages

The objective of this study was to determine the apparent metabolisable energy corrected for nitrogen balance (AMEn) of some products containing glycerine from soybean oil (GOIL), a mixture of frying oil and lard (GMIX) and a semi‐purified process (GSP) in broilers of different ages (10, 20, 30 and 40 days post‐hatching), using two methodologies. In trial 1, the basal diets were replaced with 100 g/kg of each studied glycerine product and the diets were supplied ad libitum. Three hundred broilers were used in five replicates, with five, four, three and three animals per cage in each age group, respectively. The AMEn was calculated for each experimental unit. In trial 2, dietary treatments included the addition of glycerine at 0, 40, 80 or 120 g/kg for each crude glycerine product, with 900 broilers in six replicates, using the same number of animals per cage as described in trial 1. Depending on the experimental unit, the feeding was restricted in 88%, 92%, 96% and 100% of estimated intake according to the Cobb guide. The AMEn was determined using linear regression between the feed intake and the AMEn of each diet. In both trials, the total excreta collection method was used. Because of the chemical composition, GMIX was not considered crude glycerine. The mean AMEn values of the products were 20.55 MJ/kg, 15.80 MJ/kg and 15.05 MJ/kg for GMIX, GSP and GOIL, respectively. There was a linear decrease (p < 0.01) in the AMEn values with the increasing age of the broilers. Numerically, it was observed that the AMEn values decreased until 28–30 day post‐hatching and then remained constant until the finishing phase. It is concluded that products containing glycerine can be used as an energy source for broilers, but that AMEn values can vary according to age. Younger broilers have a higher capacity of energy utilisation from these feedstuffs.     

基于差示扫描量热法和热力学模型的生物柴油结晶行为分析

棕榈酸甲酯(C16:0)、硬脂酸甲酯(C18:0)和油酸甲酯(C18:1)是生物柴油的主要组成部分。为了深入探究生物柴油的结晶行为,该文基于差示扫描量热法(differential scanning calorimetry,DSC)分析了这3种脂肪酸酯的物性参数,研究发现饱和脂肪酸甲酯C16:0和C18:0的熔点和熔化焓远远高出不饱和脂肪酸甲酯C18:1的值,C16:0和C18:0的熔点分别为301.57、310.92 K,C18:1的熔点为255.01 K。对脂肪酸酯组成的二元溶液进行DSC扫描,DSC曲线出现了2个放热峰,并且溶液的结晶点要低于首先析出的饱和脂肪酸酯纯物质时的熔点;随着饱和脂肪酸酯质量分数的增加溶液的结晶点温度也相应提高。将生物柴油当作由多元脂肪酸甲酯的混合溶液时,C16:0和C18:0等饱和脂肪酸甲酯作为溶质,C18:1等不饱和脂肪酸甲酯作为溶剂,建立了热力学模型计算溶液的结晶点温度。将脂肪酸甲酯的混合溶液近似为理想溶液时对此模型进一步简化,并利用简化模型计算得到4种生物柴油的结晶温度,与实测值进行比较得到了很好的验证效果。该研究可为优化生物柴油低温流动性的技术措施提供参考。     

Potential for greenhouse gas emissions from soil carbon stock following biofuel cultivation on degraded lands

Consequent to the interest in converting degraded lands for cultivation of biofuel crops, concerns have been expressed about greenhouse gas (GHG) emissions resulting from changes in soil‐carbon (C) stock following land conversions. A literature‐based study was undertaken for estimating the magnitude of emission of GHGs, particularly carbon dioxide (CO₂), following an assessment of the extent and causes of land degradation and the nature of CO₂ emission from soils. The study estimated the potential for CO₂ emission resulting from changes in soil‐carbon stock following land conversions, using oil palm (Elaeis guineensis Jacq.) as a case study. The analysis indicated that, overall, the magnitude of CO₂ emission resulting from changes in soil C stock per se following opening up of degraded land would be low compared with other potential sources of CO₂ emission. However, lack of data on critical aspects such as baseline soil C status was a limitation of the study. Soil respiration is the single best measure of GHG emission from soils. Fixation of C in additional biomass will compensate, over time, for C loss through soil respiration following a change in land use or land management, unless such changes involve conversion of existing large C stocks. Therefore, any net CO₂ emission from soils resulting from changes in soil C stock following opening up of degraded land is likely to be a short‐term phenomenon. The estimations used in the study are based on various assumptions, which need to be validated by experimental field data. Copyright © 2010 John Wiley & Sons, Ltd.