乙醇对棕榈酸甲酯液滴蒸发特性的影响研究

由于使用化石能源带来的环境污染,寻找具有高能量密度的环保型生物燃料成为研究热点之一。采用挂滴法研究常压下温度为773 K和873 K时含有不同乙醇浓度（10%、20%、30%和40%）的棕榈酸甲酯混合燃料的蒸发特性。结果表明,每种液滴在平稳蒸发阶段都符合经典d²定律,当乙醇浓度达到40% 时,混合燃料液滴的寿命明显缩短,平均蒸发率显著增高,尤其在环境温度为873 K时,这种提升更为明显。     

癸酸-棕榈酸二元复合相变材料的相变特性研究

通过熔融共混法制备一系列二元脂肪酸复合相变材料,并利用步冷曲线法确定癸酸-棕榈酸(CA-PA)二元复合相变材料的最佳质量配比为86∶14,其共晶温度为22.1℃。采用傅里叶红外光谱仪(FT-IR)、冷热加速循环实验和瞬态平面热源法(TPS)等研究CA-PA复合相变材料的结构与性能,发现CA-PA的FT-IR曲线上同时存在CA和PA的特征吸收峰,表明CA与PA是通过分子力作用在一起的。然后对CA-PA进行400次5~80℃冷热加速循环后,发现其相变温度变化不大于0.5℃,可见CA-PA热稳定性良好,且导热系数为0.151 W/(m·K)。同时,根据差示扫描量热仪(DSC)分析得到CA-PA的相变温度和相变潜热分别为21.78℃和154.7 J/g,这与通过步冷曲线得到的共晶温度十分符合,因此该CA-PA复合相变材料适用于建筑节能和热回收领域。     

棕榈酸-十六醇/膨胀珍珠岩复合相变材料的性能研究

以棕榈酸-十六醇低共熔物为相变材料,膨胀珍珠岩为基体,采用真空浸渗的方法,制备出棕榈酸-十六醇/膨胀珍珠岩复合相变储热材料。采用ESEM、FTIR、DSC、熔化凝固过程分析对该复合材料进行了结构和性能研究。结果表明:棕榈酸-十六醇被有效地包封在膨胀珍珠岩内,与膨胀珍珠岩基体的化学相容性良好;该复合材料具有较高的相变潜热和较好的热稳定性,并且通过在复合材料中添加10%(质量分数)石墨,改善了材料的导热性能。     

棕榈废弃物直燃发电技术研究及经济性分析

针对马来西亚的棕榈废弃物生物质燃料,进行了元素分析、工业分析和灰熔融性分析和灰成分分析,并与国内生物质燃料对比。结果表明,棕榈壳的水分低、热值高、灰熔点高,适用于直燃发电。棕榈空果串和棕榈纤维水分高、热值低、灰熔点较低,且碱金属、氯含量较高,有较高的结渣倾向;根据燃料特性,提出了有关锅炉设计的建议措施和技术可行性分析;以棕榈空果串为例进行了直燃发电经济性分析,项目总投资静态回收期为7.65年,具有良好的经济收益。     

基于气相色谱法的油酸甲酯热氧化降解动力学研究

为了考察油酸甲酯的热氧化降解特性,采用自制的氧化模拟装置将样品加速氧化,定时取样,利用气相色谱测定油酸甲酯在不同温度下的氧化曲线;通过Rancimat法加速氧化试验,测定了油酸甲酯的氧化诱导期;同时采用一个简单连串反应模型,求出了反应速度方程的积分形式,利用微分法和积分法获得了相应动力学参数,确定了反映油酸甲酯热氧化降解历程的宏观反应动力学方程式,为进一步建立生物柴油高温热氧化衰变模型提供数据支持。     

加工高酸原油的防腐措施探讨

指出选择加工高硫、高酸、重质劣质原油将是炼油企业的发展趋势,高酸原油的加工将受到越来越多的关注。通过对高酸原油加工的防腐措施和工艺技术方案进行了探讨,指出在装置选材上高温硫造成的腐蚀采用0Cr13基本可以解决,高温环烷酸腐蚀应采用316L;在加工工艺方面应重视原油的电脱盐、塔顶“三注”以及脱金属工作,选材与工艺相结合。才能更好地做到防腐。     

异丁醇/辛酸甲酯混合燃料预混层流火焰速度的研究

针对生物柴油与醇类混合燃料燃烧机理研究的需求,采用高速纹影光学诊断方法和定容燃烧弹系统试验研究了异丁醇/辛酸甲酯混合燃料的预混层流燃烧特性。测量了不同当量比和初始压力条件下的不同配比混合燃料—空气预混合气的层流燃烧火焰速度,火焰拉伸率以及马克斯坦长度。分析了燃烧初始条件及异丁醇掺混比例对混合燃料的无拉伸层流燃烧速度及火焰不稳定性的影响规律。结果表明:异丁醇/辛酸甲酯混合燃料的拉伸层流火焰传播速度和层流火焰燃烧速度随着当量比的增加先增加后减少,随着初始压力的增加而减小;马克斯坦长度随着当量比和初始压力的增加而减小;异丁醇掺混比例的增加加快了层流火焰燃烧速度,但使得火焰的不稳定性倾向增加。     

酸析及混凝法处理切削废水研究

采用酸析、混凝、酸析-混凝联合法处理切削废水,并在优化的参数条件下对比了3者的处理效果.综合结果表明,酸析-混凝联合处理最为理想,因此酸析-混凝联合法具有经济、高效的优势.     

增压柴油机燃用不同掺比菜籽油甲酯的燃烧和排放的试验研究

在D6114ZLQB车用增压柴油机上比较研究了不同比例的菜籽油甲酯和0号柴油的混合燃料对发动机燃烧过程、燃油经济性和排放特性的影响。试验结果表明：燃用体积比低于15%的菜籽油甲酯,发动机的缸内燃烧过程和纯柴油基本一致;增压柴油机燃用菜籽油甲酯和柴油的混合燃料可以有效降低碳烟、HC和CO的排放;NOx排放略有上升;15%以内的菜籽油甲酯对柴油机燃料经济性影响很小。研究认为：增压柴油机相对自然吸气式柴油机具有更好的生物柴油燃料适应性;在不改变发动机参数的条件下,低比例的菜籽油甲酯具有良好的推广应用前景。     

柴油机燃用乙醇-甲酯-柴油时PM排放特性的研究

采用甲酯作为助溶剂,使得乙醇在柴油中的添加比例达到30％。在此基础上研究了一台4缸柴油机燃用乙醇甲酯柴油时氧含量对烟度、微粒总排放、组分及粒径分布的影响,并对微粒中可溶性有机物、干碳烟的质量百分比进行了分析。结果表明:含氧燃料能够大幅度降低排放的烟度和微粒。氧含量越多烟度降低的效果越明显,而PM的降低幅度小于烟度,这是由于可溶性有机物的排放特点造成的。氧含量改变了PM中三组分的比例,氧含量越多,可溶性有机物的百分比越大,干碳烟的百分比越小。含氧燃料使得微粒粒径分布向小粒径方向移动,小于0．2μm的微粒比例升高。     

Thermophysical properties of molten tungsten measured with an electrostatic levitator

Thermophysical properties of liquid and supercooled tungsten were measured using non‐contact techniques in combination with an electrostatic levitator. Over the 3125–3707 K temperature range, the density measurements can be expressed as ρ (T) = 16.7(± 0.33)× 10³ ? 1.08(± 0.08) (kg? m^?3) with T_m = 3695 K, leading to a volume expansion coefficient of 6.6×10^?5 K^?1. In addition, over the 3398–3695 K temperature range, the surface tension (γ) and viscosity (η) data can be expressed respectively as γ (T) = 2.48× 10³(± 75) ? 0.31(± 0.08) (T ? T_m) (10^?3 N? m^?1) and η (T) = 0.11(± 0.02) exp[12.8(± 4.1) × 10⁴/(RT)] (10^?3 Pa? s). © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(2): 152–164, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20101     

气泡雾化喷嘴在不同液体物性下的喷雾特性研究

利用PS-Ⅱ激光衍射粒度仪测量分析了气泡雾化喷嘴在雾化不同动力粘度,不同表面张力的液体时的特性,发现液体的粘性对于气泡雾化效果影响程度不大,随着动力粘度的增加,平均直径稍有增大,当动力粘度很高时由于泡状流更容易形成,所以平均直径有所减小,而液体表面张力的变化对于雾化质量的影响显。     

Solidification characteristics of a droplet on a horizontal cooled wall

An experimental and numerical study of solidification characteristics of a droplet on a horizontal cooled wall is reported. Pure water and molten salt were utilized as the testing liquids. The droplet was cooled under a variety of conditions such as wall temperature and initial liquid temperature in a static atmosphere. Extensive observations of both solidification characteristics and morphologies of the droplet were made. Numerical calculations based on the Landau method considering the effects of both surface tension at the droplet surface and the density inversion at 4 °C within the droplet were carried out. It was found that the numerical results are qualitatively in good agreement with the experimental results except for the terminating period of solidification. © 1998 Scripta Technica, Heat Trans Jpn Res, 26(7): 469–483, 1997     

稀土固体超强酸SO42-/SnO2-CeO2催化合成生物柴油

以工业棕榈酸和甲醇为原料,采用溶胶-凝胶法制备稀土固体超强酸催化剂SO42-/SnO2-CeO2,催化合成生物柴油。考察了稀土氧化铈添加量、焙烧温度、焙烧时间、硫酸浓度、醇酸质量比、催化剂用量和反应时间对酯化反应的影响。结果表明,当氧化铈添加量为5%时,在2.0 mol/L硫酸浸渍后,于550℃下焙烧3 h制备的催化剂性能最好。正交试验结果表明,合成生物柴油的优化条件为醇酸质量比为15∶25,催化剂用量为棕榈酸质量的4%,反应时间为4 h,在此条件下,酯化率为95.4%。经GC-MS分析,酯产物主要为直链十六烷酸甲酯和10-十八碳烯酸甲酯。     

Dynamic Interfacial Tension between Crude Oil and Dodecylmethylnaphthalene Sulfonate Surfactant Flooding Systems

Abstract

The surface tension of surfactant aqueous solutions and dynamic interfacial tensions (DIT) between crude oil, offered from Shengli Oil Field in China, and surfactant flooding systems, and the single-component dodecylmethylnaphthalene sulfonate (DMNS) surfactant, developed in our laboratory, were measured. In the present report, both buffered alkali and no alkali flooding systems were investigated. It was found that DMNS surfactant possessed great capability and efficiency of lowering the solution surface tension and the critical micelle concentration (cmc) is 0.002 mass% and the surface tension at this concentration is 29.39 mN.m^?1. It was also found that the DMNS surfactant is also greatly effective in reducing the interfacial tensions and can lower the tension of crude oil-water interface to ultra-low at very low surfactant concentration and an optimum range of sodium chloride. The lower alkali concentration is favorable for lowering DIT. The higher alkali concentration needs a higher surfactant concentration for oil flooding systems lowering DIT. Moreover, the results indicate that there obviously exists both synergism and antagonism among the surfactant, alkali and inorganic salt. The added surfactant play an important role in reducing DIT, and the prepared DMNS surfactant possesses great capability and efficiency in lowering the interfacial tension between oil and water. The salt-modified surfactant flooding systems without alkali, decreasing the cost of oil recovery and avoiding the stratum being destroyed would have a great prospect for enhanced oil recovery.     

马赫-曾德尔干涉法测量液体折射率的改进

液体折射率是物理、化学、生物等学科的重要基础数据。干涉法是测量液体折射率的常用方法,利用实验本体的旋转角度和干涉条纹变化数量的函数关系来测量液体折射率。基于马赫-曾德尔干涉法,改进了实验原理,利用线性关系消除了实验本体产生的附加干涉条纹,建立了一种特殊的数据处理方法精确得到了θ=0°即激光垂直入射本体视窗的位置。使用蒸馏水对液槽厚度进行了校核,测量了t=20℃下乙醇、丙酮和环己烷的折射率验证了实验系统的可靠性。同时对实验系统的测量精度进行了分析,实验的测量不确定度为10-4量级。     

四种太阳池工质的浓度与折射率和温度的关系

选取可用作太阳池工质的ＮａＣｌ、ＣａＣｌ２、ＭｇＣｌ２和Ｎａ２ＣＯ３四种水溶液，对浓度Ｓ－折射率ｎ－温度Ｔ之间的关系进行测定，利用计算机对实验曲线进行拟合，给出相应的多项式回归方程，获得了较好的结果。它可用于分析、确定上述四种盐水溶液在太阳池内的浓度分布和变化，便于保持太阳池的稳定性。     

Environmental effect of rapeseed oil ethyl ester

Exhaust emission tests were conducted on rapeseed oil methyl ester (RME), rapeseed oil ethyl ester (REE) and fossil diesel fuel as well as on their mixtures. Results showed that when considering emissions of nitrogen oxides (NO_x), carbon monoxide (CO) and smoke density, rapeseed oil ethyl ester had less negative effect on the environment in comparison with that of rapeseed oil methyl ester. When fuelled with rapeseed oil ethyl ester, the emissions of NO_x showed an increase of 8.3% over those of fossil diesel fuel. When operated on 25–50% bio-ester mixed with fossil diesel fuel, NO_x emissions marginally decreased. When fuelled with pure rapeseed oil ethyl ester, HC emissions decreased by 53%, CO emissions by 7.2% and smoke density 72.6% when compared with emissions when fossil diesel fuel was used. Carbon dioxide (CO₂) emissions, which cause greenhouse effect, decreased by 782.87 g/kWh when rapeseed oil ethyl ester was used and by 782.26 g/kWh when rapeseed oil methyl ester was used instead of fossil diesel fuel. Rapeseed oil ethyl ester was more rapidly biodegradable in aqua environment when compared with rapeseed oil methyl ester and especially with fossil diesel fuel. During a standard 21 day period, 97.7% of rapeseed oil methyl ester, 98% of rapeseed oil ethyl ester and only 61.3% of fossil diesel fuel were biologically decomposed.