Usage of a traversing beam gamma densitometer measurement for the phase fractions distribution of a mixture of water and kerosene was achieved experimentally in a horizontal pipe tube. The phase fractions distribution was determined with the beam being traversed in three directions for example 0, 45 and 90° of the vertical line passing through the axis of the pipe tube. Measurement was made at two positions spaced into 2.54 cm internal diameter along the 9.7 m pipe length (1.0 m and 7.72 m along the horizontal pipe tube) with two input water fractions of 0.4 and 0.6. The measurement was done in two-phase oil water experimental rig (TOWER) facility. This facility allows the two fluids to be fed to the test section before they separated throughout the coalescer and returned once again to the test line. The flow developed naturally from an initial stratified flow in which the oil and water were introduced separately at the top and the bottom of the test section, respectively. The flows were such that the liquids were fully inter-dispersed by the end of the test section. The phase fractions distribution was shown to be homogeneously mixed near to the outlet of the test section. The mean hold-up was found to depend on the mixture velocity.
The effect of shear rate on heteroaggregation behavior of latex polymers and suspension polymers in aqueous media was investigated. Heteroaggregation was carried out in a stirred vessel under various stirring rates and temperatures. Large suspension polymer particles were selectively coated by small latex polymer particles at specific stirring rates corresponding to each temperature. The heteroaggregation dynamics were analyzed from the cluster strength of the coating latex polymer layer and external shear force. The cluster strength of the latex polymer was determined by using Usui’s rheology model, where the inter-particle bonding energy was derived from both the rheological data and the rate of energy dissipation per unit mass in the stirred vessel. In contrast, a relation between the diameter of the cluster of the latex polymer particles and apparent shear rate was derived from Kobayashi’s theory, which is based on the theoretical treatment on the break-up of a droplet. By combining both theories, the heteroaggregation process was characterized by the cluster strength of the latex polymer layer against the external shear force. The homogeneous coating was only formed in a specific condition where the favorable balance between the external shear force and the cluster strength of the latex polymer layer was achieved.
Application of high frequency ultrasound for generating a fine droplet mist has been recently applied for fine chemical manufacturing, pharmaceutical production, cleaning and agitation/mixing. A recent development is the enrichment of alcohols from miscible alcohol–water mixtures using ultrasonic atomization. In this work, the effect of high frequency ultrasonic atomization at 1.6 MHz on the separation of ethanol from ethanol–water feed mixtures has been studied. Experiments for evaluating this novel separation process were conducted in a constant volume separation system. Well-controlled experiments were performed to analyze the separation of ethanol–water feed mixture at different temperatures (between 283 and 313 K). An interesting aspect of the separation process is the concentration of ethanol above the vapor–liquid equilibrium curve above 40 mol% ethanol feed concentration. It was found that the enrichment ratio was not affected by feed solution temperature. However, mist generation rate increased with increasing feed temperature. An understanding of the role of the ultrasonic jet formed at the surface of the feed solution combined with the separation characteristics of ethanol–water feed mixtures has been discussed here and the dependence of the process on acoustic cavitation has been elucidated.
A correlation of the average drop size in a rotating disc contractor is presented. The rotating disc contactors were studied under various conditions. Various items of importance are system physical properties, column geometry, disc speed and hole distributor diameter. Two systems water (continuous phase)/acetic acid/toluene (dispersed phase) and water (continuous phase)/succinic acid/n-butanol (dispersed phase) were used to give correlation. The correlation was fitted by software. The R-squared and Durbin-Watson state in this prediction are about 95% and 1.82, respectively. The average absolute value of the relative error, AARE, is about 2.2%.
A mordenite membrane was prepared on the outer surface of a porous α-alumina tubular support by a secondary-growth method. Permeation tests for water/methanol/hydrogen mixtures were performed at 423 and 473 K. A mordenite membrane free from non-zeolitic pores allowed us selective permeation of steam and blocked the permeation of hydrogen and methanol. In order to elucidate the mechanism of such selective permeation behavior, adsorption, permeation, and structural properties of the mordenite membrane were discussed. As a result, it was considered that selective permeation of steam against hydrogen was based on its preferential adsorption of steam, while boundaries between mordenite crystals in the membrane may play a key role for inhibiting the permeation of methanol.
Liquid–liquid equilibria (LLE) of the multi-component system of water + 2,3-butanediol + oleyl alcohol were studied under atmospheric pressure and at temperatures 300.2, 307.2 and 314.2 K. The mutual oleyl alcohol + water solubility with the addition of 2,3-butanediol was investigated. The system studied formed a type I liquid–liquid phase diagram. The results were used to estimate the interaction parameters between each pair of components in the system for the UNIQUAC activity coefficient. The UNIQUAC model fitted the experimental data with an average root mean square deviation (rmsd) of 3.38%.
In this paper, we present activity models of chemical process design integrating environmental, health and safety (EHS) evaluation as a new element with conventional economic and technical considerations on the basis of the design framework, which defines different stages of early process design with appropriate indicators for multiobjective evaluation. The type-zero method of Integrated DEFinition language or IDEF0 is selected as an activity modeling method for the hierarchical and transparent description of complex design activities. The viewpoint of the activity model is the user of this design framework, i.e. a design-project manager who leads a group of process chemists and engineers. A set of template models is developed, which describes how a manager executes a project step by step with providing instructions and resources appropriately. According to this template, IDEF0 models of the design framework are created, and here EHS-related activities, tools and information are systematically defined as a part of the whole design activity. As further analysis, sub-activities are presented in detail, where the manager allocates resources appropriately to different design stages, including methods of environmental Life Cycle Assessment (LCA) and EHS hazard evaluation. Another detailed analysis is on how design constraints, e.g., market situation, competitors’ patents and company culture, affect different decision-making within the framework. The actual development of methyl methacrylate (MMA) processes is investigated as a case study. The paper finally presents important know-how for the design manager in executing the integrated design framework.
In this paper, a new supervised clustering and classification method is proposed. First, the application of discriminant partial least squares (DPLS) for the selection of a minimum number of key genes is applied on a gene expression microarray data set. Second, supervised hierarchical clustering based on the information of the cancer type is subsequently proposed to find key gene groups and to group the cancer samples into different subclasses. Here, the weights of the genes in the DPLS are proportional to their importance in the determination of the class labels, that is, the variable importance in the projection (VIP) information of the DPLS method. The power of the gene selection method and the proposed supervised hierarchical clustering method is illustrated on a three microarray data sets of leukemia, breast, and colon cancer. Supervised machine learning algorithms thus enable the subtype classification 3 data sets solely on the basis of molecular-level monitoring. Compared to unsupervised clustering, the supervised method performed better for discriminating between cancer types and cancer subtypes for the leukemia data set. The performance of the proposed method, using only a limited set of informative genes, is demonstrated to be comparable or better than results reported in the literature for the three data sets. Furthermore the method was successful in predicting the outcome of medical treatment (success or failure) based on the microarray data, which could make the method an important tool for clinical doctors.
The deactivation mechanism of a commercial Ni/Al2O3 catalyst used during coal volatile decomposition was investigated by transmission electron microscopy–energy dispersive X-ray spectroscopy (TEM-EDS), X-ray diffraction (XRD) and nitrogen adsorption. The existence of carbonous species in the reaction system promoted nickel particle growth during coal volatile decomposition, and subsequent coking from volatile cracking. Throughout the catalyst deactivation tests, coke deposits were observed as encapsulating carbon in the spent catalyst, and nickel particles doubled in size from around 10 to 20 nm. The spent catalyst was regenerated in oxygen at relatively moderate conditions by removing the coke deposits. As a result, the catalyst activity was restored remarkably; 1.7 times the surface area and double pore volume were present in the regenerated catalyst compared to the spent catalyst. Also, the regenerated catalyst showed high activity for coal volatile decomposition. Under catalysis of the regenerated Ni/Al2O3, the tarry material in coal volatile matter could transform much more completely, gaining both high gas yields and high carbon balance. We also found that methanation is structure sensitive to nickel particles. Under the action of the regenerated catalyst, CO formed during coal volatile decomposition could not be further converted into methane, and the product gases provided a higher CO concentration. Noticeably, tar decomposition was confirmed to be less structure sensitive to the nickel particles than CO-methanation.
In this study, we propose a new hybrid process consisting of glycolysis/methanolysis and then a vapor methanolysis process to obtain dimethyl terephthalate (DMT) and ethylene glycol (EG) in the depolymerization of waste poly(ethylene terephthalate) (PET). Zinc acetate was used to catalyze the reactions. We found that the depolymerization rate increased remarkably when glycolysis and methanolysis reactions were simultaneously carried out than when the glycolysis reaction was performed alone. We explored the possibility of the hybrid process and examined optimal weighting between glycolysis and methanolysis in the glycolysis/methanolysis step to increase the DMT yield and production rate. We also investigated the effect of major process variables such as reaction pressure, reaction temperature, reaction time, amount of EG, and methanol feed rate on process performance. We found that methanolysis has a greater role than glycolysis in the glycolysis/methanolysis step and the DMT yield has a maximum at a reaction temperature of 513.15 K and EG/PET mole ratio of 0.52, and increases with reaction pressure.
Complete decomposition of organic wastes using thermally-generated holes in titanium dioxide at high temperatures has been investigated. In view of the practical use of the present systems, fixation of TiO2 particles on substrates seems to be the core technology. To realize this, we have investigated direct oxidation of Ti or Sn-coated Al2O3 balls in order to prepare thin layers of TiO2 or SnO2 on the Al2O3 surface, respectively. Formation of TiO2 of the rutile phase or SnO2 has been identified by Raman spectra. In addition, complete decomposition of toluene (as an example of volatile organic compounds) has also been confirmed by the TiO2 or SnO2-coated Al2O3 balls at about 500°C.
At undergraduate level, the separation of binary mixtures is studied using, mainly, the McCabe–Thiele method because of the advantage to present the results in graphical form. However, most of the applications are limited to problems where extreme (top and bottom) compositions and reflux ratio are specified and the objective is to determinate the number of stages. By the use of the McCabe–Thiele method and the advantage of a solve-package (Mathcad™), a procedure is proposed to solve problems with different specifications. Unlike the traditional application, the number of stages can or can not be specified. Depending on the available information, the objective can be one of determining top or bottom composition and reflux ratio, for instance. The proposed procedure allows for detailed analysis of the separation, avoiding the cycle “right solution or wrong solution”. The proposed procedure is also valid for columns with multiple feeds and can be implemented by using other software.