scholarly journals Evaluation of the Efficiency of Transfer Processes in a Rotary Apparatus

2021 ◽  
Vol 64 (5) ◽  
pp. 459-474
Author(s):  
A. M. Volk ◽  
A. I. Vilkotsky ◽  
O. N. Pyzhcova
Keyword(s):  
Mass Transfer ◽  
Gas Flow ◽  
Heterogeneous Media ◽  
Chemical Interaction ◽  
Phase Interface ◽  
Experimental Studies ◽  
Gas Production ◽  
Liquid Droplets ◽  
Working Volume ◽  
Developed Surface

This paper considers the possibility of using vortex devices for interphase interaction while carrying out various physical and chemical processes in the chemical, food, gas production, construction and other industries. In the processes of mass transfer, one or several distributed components perform the transition from one phase to another through the active surface of their interface. To perform the implementation of these processes in absorbers, rectifiers, adsorbers, extractors effectively, the developed surface of the interacting phases acquire s a particular significance. Most of the chemical reactions in reaction devices and heterogeneous media occur when the initial distributed substances are supplied to the reaction zone and when the resulting products are removed from the chemical interaction zone through the phase interface. The processes under consideration are also used in solving environmental problems, viz. for sanitary cleaning of ventilation gases, wet cleaning of emissions. During evaporation, absorption, rectification, wet cleaning of gases and other processes, the problem of preventing the entrainment of liquid droplets with the gas flow is of great importance. One of the designs of a rotary multistage mass transfer apparatus is considered which makes it possible to achieve a finely dispersed liquid spray, uniform in height, with an ascending cross-flow of gas. The diagrams of installations for carrying out the experiment are given. On the basis of experimental studies, the dependence of the average diameter of dispersed liquid droplets on the geometric and hydrodynamic parameters has been obtained. The dispersed composition is described and dependences are given for determining the main characteristics used in physicochemical processes. The theoretical calculation of the movement of particles of the dispersed phase in the working volume of the apparatus at different flow rates of liquid and gas has been carried out. Theoretical and experimental methods were used to estimate the carryover of the liquid phase, an analysis of the process was carried out, and practical recommendations were given.

Influence of suspended solid particles on gas-liquid mass transfer coefficient in a system stirred by double impellers

2009 ◽  
Vol 63 (2) ◽  
Author(s):  
Anna Kiełbus-Rąpała ◽  
Joanna Karcz
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
High Speed ◽  
Gas Flow ◽  
Research Work ◽  
Experimental Studies ◽  
Solid Particles ◽  
Solid Concentration ◽  
Volumetric Mass Transfer Coefficient

AbstractThe aim of the research work was to investigate the effect of the presence and concentration of solid particles on the gas-liquid volumetric mass transfer coefficient in a mechanically stirred gas-solid-liquid system. Experimental studies were conducted in a tall vessel of the diameter of 0.288 m, equipped with two designs of double stirrers. Three high-speed stirrers were used: A 315, Smith turbine, and Rushton turbine. The following operating parameters were changed: gas flow rate, stirrer speed, and solid concentration. The volumetric mass transfer coefficient was determined using the dynamic gassing-out method. In the range of the measurements conducted, this coefficient was strongly affected by both the presence and the concentration of particles in the system. Generally, a low concentration of particles in the system, equal to 0.5 mass %, caused an increase of the volumetric mass transfer coefficient values for both stirrer configurations compared to a system without solids whilst more particles (2.5 mass %) caused a decrease of this coefficient. It could be supposed that an increase of slurry viscosity affected the decrease of the volumetric mass transfer coefficient at higher solid concentration. An empirical correlation was proposed for volumetric mass transfer coefficient prediction. Its parameters were fitted using experimental data.

scholarly journals Investigation of the Process of Simple Distillation in Irrigated Pipe Elements

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 2047
Author(s):  
Artem Sergeevich Ponikarov ◽  
Sergey Ivanovich Ponikarov ◽  
Eduard Vladislavovich Osipov
Keyword(s):  
Mass Transfer ◽  
Gas Flow ◽  
Phase Interface ◽  
Oil Refining ◽  
Side Reactions ◽  
Volatile Components ◽  
Heat Conducting ◽  
Mass Transfer Equation ◽  
Separation Processes ◽  
Cross Sectional

In modern chemical and oil refining complexes, separation processes are among the most popular and energy-intensive. Installations for their implementation should be equipped with nodes for creating vapor (evaporators) and liquid (deflegmators) irrigation. Evaporators of any type (film, thermosiphon, gas lift, cubic) belong to this class of devices. For example, in cubic evaporators, the gas flow is completely formed from flux bubbles that originate on the heat-conducting surface and float in the volume of the cubic liquid located in the apparatus. Due to the accompanying mass exchange, the bubbles are enriched with volatile components during ascent and noticeably increase in volume, and the growth of the bubble is determined, among other things, by the total flow. At the same time, in real bubbling-type equipment, the total mass transfer surface exceeds the cross-section of the device itself by more than two orders of magnitude. Thus, according to, the ratio of the internal cross-sectional area of the apparatus to the developed mass transfer surface is 0.0015–0.002. Based on the analysis of the integral equation of the diffusion boundary layer, it is shown that the presence of a resultant flow of substance through the phase interface (non-equimolarity of the process) in a two-phase gas (vapor)–liquid system leads to the transformation of the structure of the traditional mass transfer equation itself. The use of a new structure obtained for both binary and multicomponent mixtures makes it possible to significantly simplify the approach to the description and generalization of arbitrary mass transfer processes. The innovativeness of the proposed approach lies in its universality for non-equimolar processes. This simplifies the creation of models of any mass transfer devices and entire production lines. In addition, the proposed approach is a good auxiliary tool for various researchers and experimenters. It should also be noted that the separation processes of many products of organic origin during heating are characterized by the appearance of undesirable side reactions (thermal decomposition, condensation, polycondensation, formation of harmful impurities, etc.), which occur most intensively in the heating zones. At the same time, the evaporation and distillation units are subject to requirements for the minimum hydraulic resistance of the structure, the maximum separation capacity (efficiency), and the minimum residence time of the product in the apparatus (equivalent to the minimum holding capacity of the structure). It was noted that the specified requirements are most fully met by film-type devices.

Perspective Biomass Carrier for Anaerobic Processing Systems of Organic Waste AIC

2020 ◽  
Vol 67 (1) ◽  
pp. 148-155
Author(s):  
Anatoliy V. Fedotov ◽  
Viktor S. Grigoriev ◽  
Dmitriy A. Kovalev ◽  
Andrey A. Kovalev
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Specific Surface ◽  
Organic Waste ◽  
Porous Ceramic ◽  
Experimental Studies ◽  
Ceramic Materials ◽  
Porous Ceramics ◽  
Developed Surface ◽  
Highly Porous

To speed up the wastewater treatment under aerobic conditions and to optimize the processes of anaerobic wastewater treatment in digesters, immobilization technologies of microorganisms and enzymes on solid carriers are used. Ceramic carriers based on aluminosilicates and alumina are one of the promising inorganic biomass carriers. (Research purpose) To study the structure of porous ceramic biomass carriers for anaerobic processing of organic waste and evaluate the prospects for their use. (Materials and methods) The substrate for anaerobic digestion was a mixture of sediments of the primary and secondary sewage sumps of the Lyubertsy treatment facilities. K-65 cattle feed was used to ensure the constancy of the composition of organic substances in substrates as a cosubstrate. The authors used the method of low-temperature nitrogen adsorption of Bruner-Emmett-Teller to study the pore structure and specific surface of solid carriers on a specific surface analyzer Quntachrome Autosorb-1. (Results and discussion) The main characteristics (specific surface, volume of micro- and mesopores, predominant pore radius, water absorption and others) of chamotte foam lightweight and highly porous corundum ceramics were determined. It was revealed that ceramic materials with a developed surface and electrically conductive material provided an increase in biogas yield by 3.8-3.9 percent with an increase in methane content by an average of 5 percent. (Conclusions) The results of anaerobic digestion showed a positive effect of both a conductive carrier and highly porous ceramic materials on the process of anaerobic bioconversion of organic waste into biogas. It is advisable to expand experimental studies on the use of a conductive carrier with a developed surface based on highly porous ceramics.

Mass Transfer Coefficients during Steel Decarburization in a RH Degasser

2008 ◽  
Vol 273-276 ◽  
pp. 679-684
Author(s):  
Roberto Parreiras Tavares ◽  
André Afonso Nascimento ◽  
Henrique Loures Vale Pujatti
Keyword(s):  
Mass Transfer ◽  
Reynolds Number ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Gas Flow ◽  
Vacuum Chamber ◽  
Volumetric Mass Transfer Coefficient ◽  
Gas Flow Rate ◽  
Rh Process ◽  
Kinetics Of

The RH process is a secondary refining process that can simultaneously attain significant levels of removal of interstitial elements, such as carbon, nitrogen and hydrogen, from liquid steel. In the RH process, the decarburization rate plays a very important role in determining the productivity of the equipment. The kinetics of this reaction is controlled by mass transfer in the liquid phase. In the present work, a physical model of a RH degasser has been built and used in the study of the kinetics of decarburization. The effects of the gas flow rate and of the configurations of the nozzles used in the injection of the gas have been analyzed. The decarburization reaction of liquid steel was simulated using a reaction involving CO2 and caustic solutions. The concentration of CO2 in the solution was evaluated using pH measurements. Based on the experimental results, it was possible to estimate the reaction rate constant. A volumetric mass transfer coefficient was then calculated based on these rate constants and on the circulation rate of the liquid. The logarithm of the mass transfer coefficient showed a linear relationship with the logarithm of the gas flow rate. The slope of the line was found to vary according to the relevance of the reaction at the free surface in the vacuum chamber. A linear relationship between the volumetric mass transfer coefficient and the nozzle Reynolds number was also observed. The slopes of the lines changed according to the relative importance of the two reaction sites, gas-liquid interface in the upleg snorkel and in the vacuum. At higher Reynolds number, the reaction in the vacuum chamber tends to be more significant.

Mass Transfer Enhancement for CO2 Absorption in Structured Packed Absorption Column

2019 ◽  
Vol 41 (5) ◽  
pp. 820-820
Author(s):  
Pongayi Ponnusamy Selvi and Rajoo Baskar Pongayi Ponnusamy Selvi and Rajoo Baskar
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Gas Flow ◽  
Aqueous Ammonia ◽  
Volume Flow Rate ◽  
Packed Column ◽  
Operating Conditions ◽  
Co2 Absorption ◽  
Absorption Column

The acidic gas, Carbon dioxide (CO2) absorption in aqueous ammonia solvent was carried as an example for industrial gaseous treatment. The packed column was provided with a novel structured BX-DX packing material. The overall mass transfer coefficient was calculated from the absorption efficiency of the various runs. Due to the high solubility of CO2, mass transfer was shown to be mainly controlled by gas side transfer rates. The effects of different operating parameters on KGav including CO2 partial pressure, total gas flow rates, volume flow rate of aqueous ammonia solution, aqueous ammonia concentration, and reaction temperature were investigated. For a particular system and operating conditions structured packing provides higher mass transfer coefficient than that of commercial random packing.

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