Ozonation Kinetics of Acid Red 27 Azo Dye: A Novel Methodology Based on Artificial Neural Networks for the Determination of Dynamic Kinetic Constants in Bubble Column Reactors

A procedure for the determination of initial parameter values for quadratically convergent optimization methods is proposed using artificial neural networks coupled with a non-stationary gas-liquid reaction model. The evaluation of the regression and the mean squared error coefficients of the neural network during its training process allow the parameter sensitivity analysis of the gas-liquid model. This analysis examines how many and which parameters of the model will be available depending on the observable information of the mathematical model. Numerical simulations show the relevance of the initial values and the non-linearity of the objective function. The methodology has been applied to the study of the reaction of the azo-dye Acid Red 27 with ozone in acid media. The rate constant is in the order of (1.6 ± 0.1) 10³ M^?1 s^?1 under the experimental conditions.     

DRY COLUMN APPROXIMATION FOR PRESSURE DROP IN SPINNING CONE COLUMNS

A rotation-related normalization of variables has been introduced, and dimensionless fundamentally based correlations have been developed, for pressure drop in a spinning cone column (SCC) in the absence of liquid flow (dry column). The pressure drop is a sum of the dynamic and the centrifugal pressure components. Under typical SCC conditions, the correlation reduces to the form of ΔP _G  = 2N _st (k _reg R o ² + k _rot ), where N _st is a number of cone sets, Ro is the Rossby number (a rotation-normalized gas flow rate), and k _reg and k _rot are empirical coefficients characterizing the flow regime and the centrifugal efficiency of the rotor, respectively. This “dry column approximation” fits the data extremely well (the variation accounted for by the correlation is 98% of the total variation). It can be used as a theoretical limit for pressure drop prediction in an SCC at low liquid loads. The pressure regimes are classified as the centrifugal (Ro < 0.2), the intermediate (0.2 < Ro < 1.0), and the dynamic regimes (Ro > 1). Based on these dimensionless boundaries, dimensional diagrams of SCC operating regimes are constructed for laboratory and commercial-scale columns. The generality of the results is discussed in terms of the applicability of the correlations to larger scale equipment, the determination of empirical coefficients, and the linkage with CFD analysis of SCCs.     

Use of waste pyrite as an alternative to gypsum for alkaline soil amelioration

The reclamation of alkaline soils is of great interest especially in arid and semi-arid climatic regions of the world. The aim of this study was to investigate the application of pyrite from the waste materials of a copper concentration plant as an alternative to gypsum application for alkaline soil amelioration. The second aim was to assess heavy metal contamination. Waste pyrite (FeS₂) obtained from a copper concentration plant and pure gypsum (CaSO₄·2H₂O) were added to soil within the columns and pots. Column-leaching tests were performed to determine the effectiveness of waste pyrite application on alkaline soil characteristics as compared with gypsum application. Greenhouse pot experiments were also conducted for evaluating the effects of these soil additives on plant growth. The results indicated that the pH and exchangeable sodium percentage of the experimental soil significantly decreased (p?<?0.01) upon waste pyrite and gypsum applications. While waste pyrite was very effective in increasing the levels of essential plant micro-nutrients and dry matter weight of wheat, it did not cause pollution or toxicological problems in the soil. The results of this study clearly indicated that waste pyrite is a good ameliorating agent and an alternative to gypsum in reclamation of alkaline soils.     

转盘—填料复合抽提塔的工业应用

茂名石油化工公司第三套糖醛处次将复合抽提塔技术应用于生产实际。通过工业实践证明复合抽提塔较好地隔合了转盘塔及填料塔的优点，具有精制效果好、处理能力大及投资效益佳等特点，为装置消除“瓶颈”、提高加工水平提供了一条新途径。     

浅议柱下独基加防水板基础设计

通过对独基加防水板实际工程设计经验的总结,对防水板的受力特点、计算原则、构造措施及设计建议进行探讨。     

Bubble columns for condensation at high concentrations of noncondensable gas: Heat‐transfer model and experiments

Carrier gas based thermodynamic cycles are common in water desalination applications. These cycles often require condensation of water vapor out of the carrier gas stream. As the carrier gas is most likely a noncondensable gas present in very high concentrations (60–95%), a large additional resistance to heat transfer is present. It is proposed to reduce the aforementioned thermal resistance by condensing the vapor–gas mixture in a column of cold liquid rather than on a cold surface using a bubble column heat exchanger. A theoretical predictive model for estimating the heat‐transfer rates and new experimental data to validate this model are described. The model is purely physics based without the need for any adjustable parameters, and it is shown to predict heat rates within 0 to ?20% of the experimental values. The experiments demonstrate that heat‐transfer rates in the proposed device are up to an order magnitude higher than those achieved in existing state‐of‐the‐art dehumidifiers. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1780–1790, 2013     

The effect of gas‐liquid counter‐current operation on gas hold‐up in bubble columns using electrical resistance tomography

BACKGROUND: In order to improve the performance of a counter‐current bubble column, radial variations of the gas hold‐ups and mean hold‐ups were investigated in a 0.160 m i.d. bubble column using electrical resistance tomography with two axial locations (Plane 1 and Plane 2). In all experiments the liquid phase was tap water and the gas phase air. The superficial gas velocity was varied from 0.02 to 0.25 m s^?1, and the liquid velocity varied from 0 to 0.01 m s^?1. The effect of liquid velocity on the distribution of mean hold‐ups and radial gas hold‐ups is discussed. RESULTS: The gas hold‐up profile in a gas–liquid counter‐current bubble column was determined by electrical resistance tomography. The liquid velocity slightly influences the mean hold‐up and radial hold‐up distribution under the selected operating conditions and the liquid flow improves the transition gas velocity from a homogeneous regime to a heterogeneous regime. Meanwhile, the radial gas hold‐up profiles are steeper at the central region of the column with increasing gas velocity. Moreover, the gas hold‐up in the centre of the column becomes steeper with increasing liquid velocity. CONCLUSIONS: The value of mean gas hold‐ups slightly increases with increasing downward liquid velocity, and more than mean gas hold‐ups in batch and co‐current operation. According to the experimental results, an empirical correlation for the centreline gas hold‐up is obtained based on the effects of gas velocity, liquid velocity, and ratio of axial height to column diameter. The values calculated in this way are in close agreement with experimental data, and compare with literature data on gas hold‐ups at the centre of the column. Copyright © 2010 Society of Chemical Industry     

The Oxidation Stability of Lubricating Oil

Abstract

Lubricating oil is generated throughout the year and collected in central locations in many communities. The studied lube oil has a boiling range of 280°C–400°C, and its physical properties were determined according to standard test methods in ASTM and International Petroleum. Solvent extraction by furfural was carried out using different feed ratios. The best ratio was 1:4 (sample:furfural). The oil was separated into its components using liquid column chromatography. It was found that the aromatic contents decreased. The structure group analysis was determined by infrared spectroscopy and refractive index-density-molecular weight methods. The oxidation stability was carried out according to ASTM method D-48 using an inhibitor. The inhibitor used was a nonionic surfactant, alkanolamide. The results showed that the oxidation stability improved using the inhibitor.     

Manipulation of vapour split in Kaibel distillation arrangements

In this paper, we want to show how we can gain more from a Kaibel distillation column by considering a degree of freedom which is normally not used. Two methods are used to study the effect of vapour split manipulation, namely a shortcut method and rigorous simulations. Using a case-study, we show that we may not be able to operate close to minimum energy requirement for some feed disturbances as we have the vapour split fixed.     

合成氨塔出入口气的气相色谱分析

阐述了合成氨塔出入口气全分析的气相色谱法。介绍了色谱条件、改进后的气路流程和操作方法。方法精密度高，准确度好，柱寿命长，以准确的分析结果指导工艺，提高了合成氨的收率。