Preparation of clean coal by flotation following ultra fine liberation

This paper reports the results of current fundamental research at the Department of Process Engineering, University of Miskolc on the processing of clean coal from Mecsek bituminous coal, Southern Hungary. The theoretical possibility of the separation of different petrographic components was proven experimentally and their liberation degree was determined based on the petrographic composition, flotation kinetic study of isolated components (groups of components), scanning electron microscopy and microprobe analyses. The mill with stirred ball media was chosen for the ultra-fine liberation of the coal components. It was revealed that along with the liberation of coal components, their surface oxidation and spontaneous agglomeration, entrapping the mineral impurities take place in ultra-fine grinding. This paper discusses the interfacial phenomena occurring in the ultra-fine grinding process and their influence on the flotation. The concept for the advanced preparation of clean coal was developed, tested and proved. The main steps of this concept are the ultra-fine liberation in the stirred-media mill, the de-agglomeration of flocs spontaneously formed during the ultra-fine grinding and the induced (hydrophobic) flocculation with the following two-step flotation in a flotation column.     

Calculation of the Thermodynamic Properties of Diatomic Substances Based on the Ornstein-Zernike Equation

The new method of calculation of intermolecular distribution functions is used to calculate various thermodynamic properties of diatomic substances (oxygen, nitrogen, ethane). Good agreement is demonstrated between the calculation and experimental data.     

Influence of the oxygen content of low-rank coals on the development of porosity during carbonization

The development of porosity in the course of carbonization of a flame coal, original and pre-oxidized, was studied by means of the adsorption of benzene and carbon dioxide. The results were compared with corresponding data for cokes from a xylitic brown coal. The influence of coal oxygen content on the formation of coke porosity and its thermal dependence is discussed.     

Robust State Feedback Control Through Actuators With Generalized Sector Nonlinearities And Saturation

In control systems, actuators often have nonlinear characteristics that can not be neglected. For linear systems driven by actuators satisfying the generalized sector condition, a robust state feedback controller synthesis method is proposed to achieve the ultimate boundedness control. The method is based on the linear matrix inequality approach and is easy to apply. As an important special case of the generalized sector condition, the saturation characteristic of actuators is discussed separately, and non‐conservative results are obtained.     

烧结富氧点火自动控制的实现与应用

介绍了长钢烧结厂在24m^2烧结机上采用富氧点火自动控制的实现与应用。     

特低渗透油层含油饱和度的一种校正方法

松辽盆地北部扶杨油层属特低渗透油层，即使采用油基泥浆取心或密闭取心样品，束缚水饱和度也难以测准。蒸馏法试验表明，若试验温度低，则束缚水蒸发不彻底，实测含水饱和度偏低；若试验温度高，则容易造成岩样粘土矿物晶间水脱水，实测含水饱和度偏高，影响了储量计算精度。为搞清特低渗透油层流体蒸发特征，开展了蒸发率试验，试验过程是：将岩样洗油后重新饱和水，再在与蒸馏法试验相同的试验条件下测定蒸发的水量。试验结果表明，有效孔隙度越小，蒸发率越低。由于两个试验过程的蒸发率近似相等，用蒸发率试验可以模拟蒸馏法试验，由此推导出束缚水饱和度计算公式。应用该公式对榆树林油田进行测算，校正前后原始含油饱和度相差１２％以上，储量相差２０×１０６ｔ以上。图２（郭海莉摘）     

C／O测井响应随源距变化的理论研究

针对井内介质分别为水、油，地层分别为３５％孔隙度饱和水砂和油砂的４种情况，采用蒙特卡罗方法模拟外径φ８９碳氧比测井仪不同源距处的非弹性散射伽马能谱。通过分析地层或井内介质不同时的Ｃ／Ｏ差值随源距变化的关系，为设计仪器推荐源距参数。     

油气两相压降数值试井模型及其典型曲线的规律

提出油气两相流动压降试井数字模型的数值解法，用此解法对均质油藏中油气两相流动试井的规律进行了研究，根据实例计算结果，分析油气两相流下典型压降试井曲线的特征，以及油、气的初始饱和度分布，两相黏度比，饱和度梯度、相对渗透率关系对试井曲线的影响和相应的作用机理，首次发现气体的存在会使油气两相试井的压力导数曲线表现出类似于单相流双重介质试井的压力导数曲线的“下凹”特征。     

转炉炼钢静态模型的初步探讨

根据转炉炼钢的物理化学反应机理，从质量平衡和能量平衡的计算出发，通过小参数变动，导出了增量式静态模型中矿石方程和供氧方程的系数。所得结论与新日铁资料基本相符。同时，还进行了炉料和产物的计算，分析了改变废钢比对生产的影响。     

An attempt to compare the performance of bioscrubbers and biotrickling filters for degradation of ethyl acetate in gas streams

This study presents a comparison of the efficiency of a bioscrubber and a biotrickling filter (BTF) for the removal of ethyl acetate (EA) vapour from a waste gas stream, under the same operating conditions. The maximum EA elimination capacity achieved in the bioscrubber was 550 g m^?3 h^?1 with removal efficiency higher than 96%. For higher EA loadings the bioscrubber was oxygen limited, which caused incomplete EA biodegradation. When pure oxygen was fed to the bioscrubber at a rate of 0.02 L min^?1, the bioscrubber recovered and could treat higher EA loadings without any oxygen limitation. The BTF achieved EA elimination capacity of 600 g m^?3 h^?1 with removal efficiency higher than 97% and the dissolved oxygen concentration remained substantially higher than in the bioscrubber. However, severe channelling and blockage of the spray nozzle occurred due to the excessive biomass growth. Overall, the bioscrubber system was easier to operate and control than the BTF, while an enhancement of the oxygen mass transfer in the bioscrubber could potentially increase its performance by up to three times. Copyright © 2005 Society of Chemical Industry