Physical and Numerical Modeling of the Slag Splashing Process

The influence of technological factors on the process of slag splashing was analyzed in the paper. The problems were solved in several stages using our own and commercial calculation programs and laboratory tests. Based on the performed calculations and simulations, factors affecting the slag splashing were determined. It was observed that the high efficiency of the process can be achieved by optimizing numerous technological parameters, e.g., flow parameters, pressure, and temperature of the nitrogen stream, height and angle of the lance position, as well as slag height into which the gas stream enters and MgO consumption. In addition, the chemical and mineralogical composition of the slag and its physicochemical parameters should be also considered. The obtained results of numerical simulations of slag splashing in the oxygen converter coincide with the results of experiments carried out using the physical model of oxygen converter. This means that the simulations well represent the real course of the slag splashing process for the studied variants.

Исследование относительной реакционной способности ароматических соединений в воздухе под действием плазмы импульсного разряда

Based on the method of competing reactions, a method for determining the relative reactivity of aromatic vapors in relation to the plasma components of a pulsed corona discharge is developed. The parameters of the relative reactivity of aromatic compounds in the air and nitrogen stream were obtained using model mixtures based on benzene, toluene, and xylene with a content of 250-500 ppm. The effect of water vapor on the process is shown. The obtained data will be useful for optimizing the processes of plasma-chemical air purification from the vapors of toxic aromatic compounds.

Purification of model biogas from toluene using deep eutectic solvents

Biogas from landfills and wastewater treatment facilities typically contain a wide range of volatile organic compounds (VOCs), that can cause severe operational problems when biogas is used as fuel. Among the contaminants commonly occur aromatic compounds, i.e. benzene, ethylbenzene, toluene and xylenes (BTEX). In order to remove BTEX from biogas, different processes can be used. A promising process for VOCs removal is their absorption in deep eutectic solvents (DES). In this work, three DES: ([ChCl] U TEG [choline chloride]:urea:tetraethylene glycol (1:2:2), [ChCl] U [choline chloride]:urea (1:2), [ChCl] DEG [choline chloride]:diethylene glycol (1:2)) and water were tested to toluene absorption in concentration of 2000 ppm v/v in nitrogen stream. The results demonstrated the high absorption capacity of toluene using DES based on glycols.

Dynamic Study of VSA and TSA Processes for VOCs Removal from Air

Volatile organic compounds are air pollutants that necessitate to be eliminated for health and environment concerns. In the present paper, two VOCs, that is, dichloromethane and acetone are recovered by adsorption on activated carbon from a nitrogen gas stream. Experimental adsorption isotherms of the two VOCs are determined at three different temperatures 298, 313, and 323 K by the dynamic column breakthrough method. The dynamic mathematical model succeeds to predict satisfactorily the experimental breakthrough curves for pure VOCs and different binary mixtures for various conditions. Thus, the validated dynamic mathematical model has been used as a simulation tool for optimization purposes of VSA and TSA processes in order to achieve the highest performances under the given constraints. The effects of the adsorption step duration, the vacuum pressure, and the desorption temperature on the recovery of dichloromethane and acetone have been studied. A recovery of 100% of the two VOCs could be attained. However, the adsorption step duration should be determined precisely so as not to affect the recovery and alter the quality of air being purified due to the breakthrough of VOCs. The vacuum pressure and the desorption temperature should be carefully chosen in order to both reduce the energy consumption and shorten the purge step duration. Regeneration by hot nitrogen stream seems to be more efficient than regeneration by reducing pressure.

DEVELOPMENT AND VALIDATION OF HPTLC METHOD FOR DETERMINATION APIXABAN IN BULK AND TABLETS

Objective: To develop a simple and sensitive, high-performance thin layer chromatographic (HPTLC) method for the quantitative estimation of apixaban in bulk and tablets.Methods: Sample of apixaban was applied on silica gel 60 F254 TLC plates under pure nitrogen stream by linomat TLC applicator. Separation was carried out by using toluene, methanol and diethylamine as a mobile phase in a ratio of 16:3:1 v/v/v. Developed TLC plates were scanned by camag TLC scanner and detection was carried out at 288 nm.Results: Rf value of apixaban was found to be 0.4. The linearity was found from 50 to 350 ng/spot. The mean percentage recovery was found to be 85.66with % RSD of 0.79.Conclusion: The present study represents first HPTLC method that deals with the estimation of apixaban. Validation results indicated that the developed method is simple, rapid, accurate, specific, sensitive and precise. The developed method was validated as per ICH Q2 (R1) guideline by studying various validation parameters like accuracy, precision, specificity, assay, LOD and LOQ. It can be concluded that the method can be used in routine analysis of apixaban in tablet dosage form.

Improved separation and utilization of light naphtha stock by adsorption process

An integrated process for separation and utilization of light naphtha stock in refineries is discussed in this paper. Normal paraffins present in light naphtha streams are first separated from nonnormal paraffins by adsorption technology. The adsorbed n-paraffins are recovered and can be used as an ideal feedstock for steam cracking, meanwhile iso-pentane or iso-pentane and iso-hexane blends are recovered by rectification of the nonadsorbed effluent and used as necessary components for modern gasoline or aviation gasoline products. From the results for a model feedstock, an isothermal adsorption and purging desorption approach is selected. Optimum parameters consist of adsorption and desorption duration of 30 min at 180℃ for each, nitrogen stream LHSV of 240 h−1 in the desorption step, the dynamic capacity of the adsorbent reaches 0.042 g/g.

OPTIMIZATION OF CONCENTRATION CONDITIONS FOR FOOD PRODUCTS WITH HIGH HUMIDITY

According to the research, for improving the properties of unripe and partly sour honey, its concentration can be achieved by increasing the evaporation surface area of the products to be processed in vacuum conditions as well as in an open boiler under the recommended mode for heating honey (up to 45 °C). To stabilize fruits and accelerate the process of concentration in the liquids as well as mechanical mixtures of liquids for jams and fruit purees, it is recommended to premix the pulp with food sugar enzymatic hydrolysate (invert sugar), then obtain the mix at relatively moderate temperature (55-60°C), for which the intensive thickening technology has been developed using the above-mentioned method (Copyright of deposition #5870,2014, “Sakpatenti”) and easily oxidizable substances of fruits are protected in gaseous nitrogen stream. Due to these changes, honey, invert sugar syrup, fruit juices and fruit pulp preserve their original properties, hydroxymethylfurfural (HMF) content in the finished product was within 0.5-5.0mg/kg, decrease of water content was 17-20 mass % in an hour, if the liquid mass concentration of the mixture was 23-64 mass%. This paper contains 1 table, 7 figures and 6 literary sources. Materials of the research, which formed the basis for the development of new technology, have not been published in any other source of scientific information.

A comparison of different methods to remove dissolved oxygen: Application to the electrochemical determination of imidacloprid

This study compares different methods for the removal of oxygen from the solution prior to the chronopotentiometric determination of the insecticide imidacloprid on glassy carbon electrode. The research included the application of the chemical method involving addition of sulfite ion, and the physical method of purging the sample with nitrogen stream, as well as their combination. By comparing analytical signals of imidacloprid, chemical method showed almost the same efficiency as conventional physical method, while the best reproducibility was achieved by applying chemical method with addition of the saturated sodium sulfite solution. The method is very simple and can be applied for deoxygenation of the solution prior to the chronopotentiometric analysis. The application of the chemical deoxygenation significantly shortened duration of the chronopotentiometric analysis of imidacloprid from approximately 15 min to 1 min.