甲基二乙醇胺-乙二醇-水混合溶剂中CO_2和H_2S的溶解度

采用自吸式搅拌鼓泡反应釜,系统测定了CO2和H2S在甲基二乙醇胺(MDEA)与乙二醇(EG)混合溶剂中的溶解度。研究表明,与MDEA质量分率30%的水溶液相比,CO2在非水MDEA混合溶剂中的溶解度下降幅度较大;而H2S在非水MDEA混合溶剂中的溶解度仅略有降低。在MDEA浓度一定的情况下,CO2和H2S的溶解度均随着混合溶剂中水含量的增加而升高,其中水含量变化对CO2溶解度的影响尤为显著。采用改进的Kent-Eisenberg简化模型,将气液平衡体系的非理想性归集于表观平衡常数K1和K2中。通过单一H2S-MDEA或CO2-MDEA体系的溶解度实验数据,由最小二乘法数据回归得出表观平衡常数K1和K2表达式,由模型计算得到的CO2和H2S酸气平衡分压平均偏差分别为4.59%和6.19%,与实验值符合较好。     

用惰性气流带出和气相色谱法测定无限稀释活度系数

用惰性气流带出和气相色谱法测定无限稀释活度系数,这一方法包括改进了平衡釜的结构以增大气液界面和加长气液两相的接触时间;采用双釜流程,在平衡釜前加一个盛有纯溶剂的预饱和器,使平衡釜内的溶剂损失减至最小。这样,使平衡釜内的气液两相达到平衡,并使溶剂不变。在计算实验结果时,考虑了平衡釜出口气流中的溶剂蒸气量,使实验结果准确可靠。     

十二烷基苯磺酸钠-异丙醇-水固液平衡实验数据测定及关联

测定了十二烷基苯磺酸钠 (SDBS)于不同温度下在异丙醇 (C3H7OH)和水 (H2 O)的混合溶剂中的溶解度 ,并考察了水中氢氧化钠 (Na OH)含量对 SDBS溶解度的影响。同时绘制出三元相图 ,并利用推导的溶解度模型对固液平衡数据进行关联 ,结果良好     

正丁醇-水-氯化钙体系液液平衡的测定和预测

测定了 2 98.15K和 32 3.15K下氯化钙在 1%～ 2 0 % (质量分数 )范围内的正丁醇 -水体系液液平衡。应用作者提出的强电解质混合溶剂体系过量自由焓模型 (1994年 ) ,仅用二元信息回归出参数后 ,对该体系的平衡双液相联结线和盐浓度分布进行预测 ,所得结果与实测相一致     

氰化氢在煤气和冷凝液中的相平衡

用气液平衡装置测定了不同温度下氰化氢在煤气和冷凝液中的气液平衡数据,并得出了氰化氢在煤气和冷凝液中的气液平衡关系式。     

电解质混合溶剂体系汽液平衡的推算

本文建立了由混合溶剂中电解质活度系数推算汽液平衡的数值计算方法。在电解质活度系数测定的盐浓度范围内,NaBr(1)-H_2O(2)-MeOH(3)和HCl(1)-H_2O(2)-MeOH(3)两体系在101.3 kPa下的汽液平衡计算结果与文献值平均绝对偏差分别为:汽相摩尔分率,平衡温度和,对前一体系还能正确地推测出交叉的盐效应规律。     

二苯基亚砜在有机溶剂中的溶解度测定和拟合

在温度288.30~334.32 K、常压条件下,采用合成法测定二苯基亚砜在乙醇、乙酸乙酯、甲苯、丙酮、氯仿以及一系列浓度的乙醇-水混合溶剂中的溶解度。实验结果表明,在相同温度下,5种纯溶剂中二苯基亚砜的溶解度大小顺序如下,氯仿丙酮甲苯乙酸乙酯乙醇;乙醇-水混合溶剂中溶解度随着乙醇浓度下降而迅速降低;该溶解过程为吸热熵增过程,且随着溶解Gibbs斯自由能增大,溶解度减小。数据采用改进的Apelblat方程和van’t Hoff方程进行拟合,在乙醇-水混合溶剂中的溶解度数据还采用Jouban-Acree方程拟合。拟合结果与实验数据基本吻合。测定的固液平衡数据可为二苯基亚砜的合成与提纯等过程的溶剂选择提供依据。     

二苯基亚砜在有机溶剂中的溶解度测定和拟合

在温度288.30～334.32 K、常压条件下,采用合成法测定二苯基亚砜在乙醇、乙酸乙酯、甲苯、丙酮、氯仿以及一系列浓度的乙醇-水混合溶剂中的溶解度。实验结果表明,在相同温度下,5种纯溶剂中二苯基亚砜的溶解度大小顺序如下,氯仿 > 丙酮 > 甲苯 > 乙酸乙酯 > 乙醇;乙醇-水混合溶剂中溶解度随着乙醇浓度下降而迅速降低;该溶解过程为吸热熵增过程,且随着溶解Gibbs斯自由能增大,溶解度减小。数据采用改进的Apelblat方程和van’t Hoff方程进行拟合,在乙醇-水混合溶剂中的溶解度数据还采用Jouban-Acree方程拟合。拟合结果与实验数据基本吻合。测定的固液平衡数据可为二苯基亚砜的合成与提纯等过程的溶剂选择提供依据。     

醋酸-水萃取精馏溶剂的筛选

采用平衡组分分析法对醋酸-水萃取精馏的溶剂进行了筛选.首先,对醋酸-水体系的常压气液平衡(VLE)数据进行了测定,并与文献值比较,同时采用Herington面积法对数据进行热力学一致性的检验,从而考察了气液平衡数据测定装置的稳定性及可靠性.然后,测定加入不同溶剂后体系的VLE数据,比较不同溶剂对体系的选择度,初步筛选出选择度最大的N-甲基乙酰胺(NMA)为醋酸-水萃取精馏的较优溶剂.     

含麝香体系多元溶液固液平衡研究

测定了酮麝香、二甲苯麝香在单一溶剂和混合溶剂中的溶解度以及酮麝香的中间体 2 ,6 二甲基 4 叔丁基苯乙酮在不同溶剂中的溶解度 ,并且测定了多溶质多溶剂体系的固液平衡 ,采用UNIFAC活度系数法进行以上体系的固液平衡计算 ,计算结果与实验测定结果吻合良好。采用文中提出的方法不仅可以预测多溶质体系在溶液中共同达到饱和时的溶解度 ,而且可以预测部分溶质达到饱和时的溶解度 ,这对于溶液结晶具有重要的指导意义     

Crystallization of linear polyethylene from melt in isothermal compression

Crystallization and primary nucleation of linear polyethylene has been studied by means of a custom-made miniature pressure apparatus. It has been shown that during isothermal compression of linear polyethylene melt at a constant rate crystallization occurs. In the range of fastest conversion rates the crystallization assumes isobaric character. The level of pressure at which the crystallization occurs increases with the increase of the crystal-lization temperature and/or with the increase of the compression rate. The crystallization has a spherulitic character up to the highest pressure achieved in the apparatus (approx. 600 MPa). Surprisingly, there are no dependencies of average spherulite size, degree of crystallinity, and lamellae thickness on the pressure and the temperature of crystallization during melt compression, but there is a strong relation to the compression rate. Below 250 MPa and above 300 MPa the crystallization proceeds under pressure, ensuring a constant undercooling. The undercooling for the pressure above 300 MPa is approximately 10°C lower than that for the pressure below 250 MPa. For the pressure 250–300 MPa a change in a primary nucleation and spherulite crystallization has been observed that is connected with the transformation from orthorhombic to pseudohexagonal symmetry of crystals. No noticeable effect of molecular weight of linear polyethylene on crystallization during iso-thermal melt compression has been observed.     

Nitrogen solubilities in low-density polyethylene at high temperatures and high pressures

An apparatus for the determination of the solubility of gases in polymers at high pressure and high temperature is described. The solubilities of nitrogen in low-density polyethylene (PE800E) at 394–450 K at pressures between 10 and 125 atm are reported. Empirical correlations are obtained which represent the Flory–Huggins interaction parameter χ, solubility coefficient K_H, and activity coefficient of dissolved gas Ω₂ as functions of temperature and pressure for the above system. © 1995 John Wiley & Sons, Inc.     

Vacuum and atmospheric pressure TGA on an eastern Canadian coal

Coal from the Prince Colliery, Cape Breton, Nova Scotia, was pyrolysed at atmospheric pressure and under vacuum at temperatures to 900 °C in a TGA apparatus. The resultant chars were then combusted in air in the same apparatus. For both vacuum and atmospheric pressure pyrolysis, chars made at temperatures under 700 °C exhibited a double-burn behaviour during combustion. Chars that were made by pyrolysis above 700 °C did not exhibit this behaviour. For the same degree of devolatilization, chars derived under vacuum exhibited lower burn temperatures than chars obtained at atmospheric pressure, and from this limited point of view may be said to be the better fuel.     

CONDITIONS ENCOUNTERED IN FILLING PRESSURE WARE*

Many beverages contain dissolved COZ which is held in solution by pressure above atmospheric. To fill these products into pressure ware calls for mechanical systems which operate at pressures above atmospheric. The bottles are thus subjected to varying conditions of internal pressure during their filling. Because the ware is usually warmer than the product, there may also be some thermal effect. The action of the filling machine and the closure application may introduce some mechanical loading. The extent and timing of these conditions depend somewhat on the type of the filling apparatus, but the general limits may be stated to give some estimation of the service demands on the ware during this particular operation.     

Dissolving poly(tetrafluoroethylene) in low boiling halocarbons

An apparatus and methodology are described for dissolving poly(tetrafluoroethylene) in relatively low boiling perhalocarbons at temperatures as high as 330°C and up to about 20 MPa pressure. Cloud points are reported for these solutions with the following solvents: n-perfluorohexane, perfluorodecalin, Freon® 113 (1,1,2-trichloro-1,2,2-trifluoroethane) and Fluorinert® FC-75 (a perfluorocarbon ether). Most of the solutions were studied above the critical temperatures of their solvents. © 1995 John Wiley & Sons, Inc.     

Lebensmittel-Gefriertechnik mit kryogener Kälte

Food freezing with cryogenic techniques . Typical for this freezing technique is the immediate contact of the goods to be frozen with the refrigerant. While in the past only nitrogen which boils at – 196°C at atmospheric pressure was seen as a cryogenic coolant, the refrigerating agents CO₂ and difluorodichlormethane (R 12) are nowadays also included in this category because some criteria of these processes correspond to those of the original cryogenic freezing technique. The principles of the cryogenic freezing technique are explained, and differences between the various processes and the refrigerants mentioned are detailed. Different types of apparatus were developed to take the conditions of the product and of the refrigerant into consideration. Here above all the physical properties of the refrigerants are important but so are the kind and the dimensions of the goods to be frozen. With reference to recently-published literature, apparatus are described which utilize the spray or dip technique. However, some apparatus works only with low temperatures without allowing the refrigerant to boil at the surface of the material to be frozen. An economics study gives information about the conditions under which the cryogenic freezing technique is able to compete with traditional freezing techniques.     

High-pressure compaction modelling of calcite (CaCO3) powder compact

Numerical simulation of manufacturing processes with working conditions at high pressure (above 1 GPa) requires constitutive data of the powder for the whole range of pressure and density. Most of the test apparatuses commonly used to obtain such data are only working in the lower pressure regions. Because of the absence of high-pressure data, many parameters have to be guessed or extrapolated. A material used in high-pressure applications is Calcite (CaCO₃). The material can be used as an insulator in high-pressure capsules it is also a common material in the earth core. An apparatus often used to generate high pressure during compaction is the Bridgman anvil apparatus. In this work experimental tests with a Bridgman anvil set-up using Calcite powder discs with different thicknesses were done. A nonlinear elastic-plastic cap model was developed to model the behaviour of powder material from low pressure and loose state to high pressure and solid state. The constitutive model was implemented in a finite element code. The constitutive data were identified by optimization of experimental data. Validation was done by numerically reproduce the mechanical behaviour of uni-axially pressing Calcite to different pressure (up to 5 GPa) including unloading. The load-displacement curves, density distribution and the surface displacement were measured and compared to the finite element results. The results of the compaction simulations agree reasonably well with the experimental results.     

The theory of the practice of steam deodorization of saponifiable oils

Summary The pressure of steam entering the deodorizer is approximately half the pressure of the steam supply. The relative dimension of the apparatus and form of the outlet may be calculated from the equation given in the paper. To shorten the time of deodorization the most important factors are low pressure in the deodorizer and high temperature of the oil. In the application of the counter current principle which amounts to the same thing as continuous deodorization the apparatus used is a tower in which the air is admitted at the top and the steam at the bottom. The whole apparatus is maintained under reduced pressure and the oil is withdrawn from the apparatus in a finished condition, while the odoriferous matter is carried over with the steam into a condenser at the top of the apparatus. The advantages which may be claimed are short time of contact with the steam and economy in the use of steam.     

Packing density and consolidation energy of flocculated aqueous SiC suspension

The applied pressure and suspension height during consolidation were continuously recorded with an aqueous 30 vol.% suspension of 0.8 μm SiC particles at pH 3.0 (near the isoelectric point) using a developed pressure filtration apparatus. The consolidation to the solid content above 46 vol.% was accompanied by a rapid increase of the pressure. The maximum packing density, where an average distance between two SiC particles was close to 0, reached 62–63% at 19 MPa of applied pressure. The consolidation energy was 1.6–1.8 J/g-SiC. The influence of the addition of polyacrylic acid (dispersant) on the consolidation energy of the SiC suspension and the strain relaxation of the consolidated SiC compact after the pressure release, are also reported.     

超临界二氧化碳介质中聚合物玻璃化转变温度

研制了一套原位光学法测定超临界二氧化碳（SC-CO₂）介质中聚合物玻璃化转变温度（T_g）的仪器装置。该仪器装置由带石英视窗的高温高压平衡釜、数据采集系统、加热与温度控制系统、压力控制系统、CO₂输送系统5部分组成。采用该仪器装置,测定了温度为50、60、70、80、90、100、120℃,压力为0.1、5、10、15、20 MPa范围内,PET聚酯薄膜样品的体积溶胀率及相应的玻璃化转变温度。常压测量结果与DSC差示扫描量热仪的测量值吻合很好,在10 MPa下的实测结果与文献值亦具可比性,表明该实验装置的可靠性及研究方法的可行性。因此,本仪器装置及方法可用于测量SC-CO₂介质中聚合物的玻璃化转变温度。