EXPERIMENTAL MEASUREMENTS OF FOAMING TENDENCIES IN AQUEOUS GAS SWEETENING SOLUTIONS CONTAINING MDEA OVER A TEMPERATURE RANGE OF 297-358K AND A PRESSURE RANGE OF 101-500KPA

This work presents experimental measurements of foaming tendencies and break times for 50 wt% aqueous solutions of MDEA in contact with nitrogen, methane, and ethane gases from atmospheric pressure to 500 kPa and temperatures from 297 to 358 K. The effect of various contaminants including methanol, HEP (1,4- bis-2-hydroxyethyl piperazine), hexane, and carboxylic acids ranging from formic to dodecanoic acid was investigated. Only those systems containing carboxylic acids heavier than valeric acid exhibited foaming. Foaming tendency in systems containing carboxylic acids was worsened by the addition of methanol and HEP, although the difference was moderate. Foaming was shown to be worse at lower pressure and at higher temperature. Foaming in MDEA systems was shown to be substantially worse than that measured previously by McCarthy and Trebble (1996) for aqueous systems of DEA.     

AN EXPERIMENTAL STUDY OF GAS HOLDUP IN TWO-PHASE BUBBLE COLUMNS WITH FOAMING LIQUIDS

Gas-liquid upward flow experiments have been performed in two bubble columns of different diameters (0.10 and 0.29 m,) using air as gas phase and several liquids: water, aqueous solutions of ethanol and glycerine, kerosene, and a solution of a surfactant in kerosene. The main goal of the study is the analysis of foaming systems, including the comparison of their behavior with respect to non-foaming systems. The gas holdup was determined experimentally as a function of the gas and liquid superficial velocities in bubbling, churn-turbulent and foaming regimes. It was found that, for foaming systems, semi-batch operation enhances foam formation, yielding higher holdups than those obtained in continuous operation at very low liquid velocities. Opposite to what is observed in non-foaming systems, the liquid superficial velocity affects the gas holdup appreciably in foaming systems. An increase in column diameter results in a decrease in gas holdup for all the systems studied. In aqueous foaming systems, this trend is more drastic since foam is inhibited as the column diameter increases.     

CORRELATIONS FOR ESTIMATING THE DIFFUSIVITIES OF NITROUS OXIDE IN AQUEOUS SOLUTIONS OF DIETHANOLAMINE AND N-METHYLDIETHANOLAMINE AND THE SOLUTION DENSITIES AND VISCOSITIES

Experimentally measured diffusion coefficients of nitrous oxide in water, aqueous solutions of diethanolamine, aqueous solutions of N-methyldiethanolamine, and aqueous blends of diethanolamine and N-methyldiethanolamine have been used to arrive at a modified Stokes-Einstein correlation by using nonlinear least-squares filling. The average deviation of this correlation from the experimentally measured diffusion coefficients is about 13%. Comparisons are also made to the estimated diffusivities of nitrous oxide in the amine solutions which are obtained from the Wilke-Chang and Hayduk-Minhas correlations. The average deviations of the Wilke-Chang and Hayduk-Minhas correlations from the measured values are about 13% and 19%, respectively. Correlations were also presented for estimating the solution densities and viscosities. Predicted values for the solution densities and viscosities from these correlations deviate from experimentally measured values on average by 1.2% and 4.8% respectively.     

油水分离用水力施流器特性的试验研究

油，水分离用水力旋流器是一种高效、节能的新型分离装置，其结构及尺寸与固、液分离用水力旋流器有较大的差别。通过研究，计算确定了水力旋流器的几何结构及各部分尺寸，并制造了一台样机，在自行设计的试验台上进行了试验研究，分离效率达９５％。同时试验了不同参数（压力Ｐ，流量Ｑｉ，浓度Ｃｉ，分流比Ｆ，尾管长度ｌ３等）对分离性能的影响，找出了一些规律，为进一步深入的研究及试验打下了基础。     

EPP泡沫填充对铝蜂窝压缩性能的影响研究

采用准静态轴向压缩实验和有限元仿真相结合的方法,对EPP泡沫(聚丙烯塑料发泡材料)填充对铝蜂窝结构压缩性能的影响开展了研究。实验发现,相对空铝蜂窝,EPP泡沫填充铝蜂窝结构的峰值力、平均抗压强度和吸收能量分别提高了1.9%~43.33%、46.59%~179.53%和46.26%~179.04%。并且相对空铝蜂窝与单独EPP泡沫之和,泡沫填充结构的平均抗压强度和总吸能分别提高了2%~23.5%和3.9%~23.3%。此外,采用Ls-dyna软件对EPP泡沫填充铝蜂窝的破坏过程进行了仿真,发现EPP泡沫填充可以有效抵抗蜂窝壁变形,并且获得了与实验较吻合的破坏过程和位移曲线。研究表明,利用EPP泡沫填充铝蜂窝,能有效改善铝蜂窝结构的轴向压缩性能。     

EFFECT OF HIGH PRESSURE ON A CO-CULTURE FOR THE PRODUCTION OF METHANE FROM COAL SYNTHESIS GAS

It has been demonstrated that coal synthesis gas may be converted to methane by anaerobic bacteria. One possible pathway involves the formation of acetate from carbon monoxide by bacteria such as P. productus. Acetate can be reacted to methane by methanogens, such as Methanothrix sp. Whenever a gas needs to react in a liquid phase, reaction rates are severely limited by mass transfer of the gaseous substrates into the liquid medium. Operation at high pressure increases the gas transport and solubility and, thus, the reaction rates. However, high concentrations of dissolved carbon monoxide are known to effects of high pressure on the performance of co-cultures capable of converting synthesis gas into methane.