甲醇-大豆油二组分物系临界参数的计算及其应用

对甲醇-大豆油二组分物系的临界参数采用 Lyderson 基团贡献法和 Prausnitz 混合规则进行计算,计算临界温度的平均误差为2%结合甲醇-大豆油二组分物系临界参数的计算结果,对由甲醇和大豆油制生物柴油的管式反应器中的流体相态进行了分析。管式反应器沿轴向依次分为扩散区、互溶区和分相区;反应温度影响甲醇和大豆油混合状况和相态的轴向分布,进而影响生物柴油收率;反应压力影响物系的密度和油脂在甲醇中的溶解度,从而影响相态的轴向分布和生物柴油收率;利用管式反应器制生物柴油较适宜的操作条件在物系的临界点附近。     

Influence of geometry and solids concentration on the hydrodynamics and mass transfer of a rectangular airlift reactor for marine sediment and soil bioremediation

Hydrodynamics and mass transfer characteristics of a three-phase airlift reactor were studied in a rectangular split-vessel reactor and using an air-seawater-marine sediment system. Experiments were conducted over a range of downcomer to riser cross-sectional area ratios (A_D/A_R = 0.65 to 1.0) for two-phase systems and for five sediment concentrations (5 to 25% w/v) using marine sediments. The influence of higher sediment concentrations (30 to 50% w/v) was examined for A_D/A_R = 1. The presence of fine sediment particles in the system had little effect on hydrodynamic and mass transfer parameters compared to the two-phase systems up to 25% loading, decreasing at higher loadings. The airlift reactor was found to meet the dissolved oxygen demand needed for a contaminated sediment treatment process. Axial distribution of the particles was uniform along the riser and the downcomer. Correlations were developed that described the hydrodynamic and mass transfer behaviour for all experimental conditions examined.     

Transient and steady state crack growth kinetics for stress corrosion cracking of a cold worked 316L stainless steel in oxygenated pure water at different temperatures

The stress corrosion cracking (SCC) growth kinetics for a cold worked 316L stainless steel was continuously monitored in high purity water at different temperatures and dissolved oxygen (DO) levels under a K (or K_max) of 30 MPa m^0.5. The total SCC test time was more than 8000 h to make sure the steady state crack growth rate under each test condition could be reached. Crack growth rate (CGR) increases with increasing temperature in the range 110-288 °C. A typical intergranular-cracking mode is identified. Depending on the previous test condition, especially the temperature, three kinds of crack growth kinetics, i.e., increasing with testing time then becoming steady, being constant during the whole period, or decreasing with test time then becoming steady, are identified and discussed. Time-dependent and testing history-dependent crack growth modes were confirmed in two series of tests in 2 ppm DO and 7.5 ppm DO pure water. The apparent activation energies are calculated and compared with other data in different environments under different applied loading levels for understanding the cracking mechanism.     

Investigation into Photocatalytic Degradation of Gaseous Benzene in a Circulated Photocatalytic Reactor (CPCR)

Due to the fact that suspended TiO₂ powder enjoys free contact with gaseous pollutant molecules in photocatalytic reactors, it can generally achieve better efficiency than immobilized TiO₂ catalysts. However, difficulties with the separation of this catalyst powder from treated pollutants and its re‐use often limit its application. Therefore, a circulated photocatalytic reactor (CPCR) was designed to enhance the performance of the photocatalytic degradation of gaseous benzene. TiO₂ film photocatalysts were prepared by the sol‐gel method at low temperatures and coated onto the inner wall of this reactor by a bonding agent composed of poly‐(2, 2‐dimethyl)‐acrylic ethylene ester emulsion in which TiO₂ powder was characterized by FTIR, TEM and SEM. In particular, the influences of initial concentration and gas flow rate of benzene on the degradation conversion, D_p, apparent reaction rate constants, k_r, initial degradation rate, r, and the deactivation and regeneration of catalyst in the CPCR, were investigated. The results indicated that the degradation conversion, apparent reaction rate constants and initial degradation rate were closely correlated to the initial concentration of benzene. To elucidate the factors governing the observations, the adsorption characteristics and kinetics of the photocatalytic degradation of benzene were analyzed using the Langmuir adsorption isotherm and Langmuir‐Hinshelwood kinetic model. It was found that the reaction kinetics were best described by a fixed pseudo‐first‐order kinetic equation of photocatalytic degradation of gaseous benzene in the CPCR.     

氮化硅陶瓷轴承在有机硅室温胶搅拌釜上的应用

分析了有机硅室温胶装置中搅拌釜底部滑动轴承在使用中易于磨损，更换频繁的原因。论述了氮化硅陶瓷材料的特点，选择了氮化硅陶瓷轴承作为有机硅室温胶搅釜底轴承并进行了相应设计。运行结果表明，采用氮化硅陶瓷轴承作为有机硅室温胶搅拌釜等设备的底部轴承具有耐磨损，耐高温，无污染，使用寿命长等特点，且有良好的经济效益和推广使用价值。     

不同布水方式下水平潜流人工湿地水动力学机制研究

通过6种布水方式（一般推流、多向入流、部分回流、波流、对角流、多点进水）下水平潜流人工湿地的脉冲示踪剂实验研究，获得其水力停留时间概率分布密度曲线。用4种不同概率分布函数（正态分布、对数正态分布、卡方分布、瑞利分布）对其水力停留时间的概率分布密度进行拟合分析，结果表明：对数正态分布的拟合效果更好。将对流扩散模型和连续反应器模型分别用于6种布水方式下的示踪剂迁移过程模拟，结果表明：连续反应器模型比较适合模拟部分回流式布水方式，对流扩散模型能够较好模拟其他5种布水方式。考虑多向入流和多点进水的示踪剂浓度叠加作用，进一步利用基于对流扩散机制的叠加模型进行示踪剂迁移过程模拟，结果表明：基于对流扩散机制的叠加模型能够较好模拟多向入流、多点进水类型的水平潜流人工湿地。     

An accurate technique of measurement of a transducer output by using a modified two core saturable reactor

Saturable reactor or transductor used as a magnetic modulator or amplifier for the measurement of the small value DC output signal of a transducer may suffer from error due to the fact that a part of the current drawn from the transducer by the transductor unit is utilized to magnetize the core material. In this paper a modified two core saturable reactor circuit has been proposed to eliminate this error. This unit also minimizes some other errors like common mode error, material error, etc. Theory of operation and design of the circuit has been explained in this paper. The circuit has been tested by using a millivolt input signal as well as a thermocouple to measure temperature. The experimental results are presented in this paper. Linear static characteristic graphs have been observed.     

X-ray computed tomography of a gas-sparged stirred-tank reactor

X-ray computed tomography (CT) is used to explore the differences in gas dispersion in a stirred-tank reactor (STR) for different operating conditions by varying the impeller speed and gas flow rate. X-ray imaging has been carried out in a 0.21 m ID acrylic STR equipped with a nylon Rushton-type impeller. From the CT images, major differences in local gas holdup are observed for different operating conditions. Completely dispersed conditions have a relatively uniform holdup profile while flooded conditions show a high gas holdup near the impeller shaft. The high resolution of the X-ray system allowed fine details such as recirculation regions behind the baffles to be visualized.     

变频调速装置在焦炉集气管压力调节上的应用

应用ＡＢ变频调速装置及ＰＩ模拟器实现了对焦炉集气管压力的微压自动调节和控制。压力稳定，运行可靠，节电效果明显，经济效益可观。在微压稳定控制领域里，极具推广价值。     

HFETR堆芯燃料管理计算方法的研究

研究了高通量工程试验堆（ＨＦＥＴＲ）堆芯燃料管理计算方法，以栅元计算程序ＷＩＭＳ－Ｄ４－ＣＮＰＲＩ和三维节块程序ＳＩＸＴＵＳ－３为基础，研制了ＨＦＥＴＲ堆芯燃料管理计算软件包ＨＦＥＴＲＦＭ。并对高通量工程试验堆首炉堆芯进行了计算，取得了令人满意的结果。