Проаналізовано математичну модель реакційної труби печі трубчастого типу – основного апарата на першій стадії конверсії метану. Одержано систему диференціальних рівнянь для подальших досліджень.
The most famous technologies of making hydrogen are based on chemical and thermal processes also on electrolysis of water. However, they major shortcomings as the use of high potential energy to the costs of fossil fuels and therefore significant pollution. The disadvantage of electrolysis of water is a significant level of power consumption. Electrolytic hydrogen is the available, but more expensive product. Today, the world's largest distribution obtained technology of developing hydrogen or a mixture of hydrogen and other gases by steam reforming of natural gas – methane. But almost half of the initial volume of gas consumed in carrying out endothermic steam reforming process. So the world is making an intensive search for such technologies that produces hydrogen, which would meet the requirements of economic and energy efficiency and environmental safety.
The process of steam reforming of hydrocarbon compounds designed to produce hydrogen technology and other process gases by high-temperature catalytic reforming in the cycle of production of synthesis gas. The process of conversion is one of the most important stages of the process of obtaining gas in ammonia synthesis loop. Despite the complexity of hardware design, steam catalytic conversion of methane in the furnace tube is currently the most economical way to get the process gas and hydrogen.
Therefore, to improve it is relevant and necessary scientific and technical challenge. Given that the full-scale study of the process of conversion is expensive, very difficult and dangerous. To solve the problems of design of process equipment, synthesis and study of control systems, simulators technical personnel, the challenge of obtaining the mathematical model of the process object that will best reproduce the properties of real prototype to a wide range of operation. However, creating of a model is based on a compromise between the complexity of the mathematical tools and depth of simplifications and neglects. Today we know a few tube type furnace models, including regression models, which are widely used because of its ability to approximate analytical relationship between input, output variables for multiple passively or actively conducted experiments, and mathematical models are based on the theory of fuzzy logic and fuzzy set theory. The general scientific problem is that with most of them do not allow modeling the dynamics of the process and, therefore, not part of the unsolved scientific problem is that it makes it impossible to optimize dynamic processes.
Розглянуто та проаналізовано математичну модель насадкового абсорбера у процесі виготовлення ацетилену з реакційних газів, у якому проходить основний процес насичення ацетилену. Одержано систему диференційних рівнянь для подальших досліджень.
There are many different ways to produce acetylene. Among them, such as manufacturing out of calcium carbide, pyrolysis of hydrocarbons and gas separation from gases which consist acetylene. All of these technologies are based on chemical or mass transfer processes, etc. However, they are energy consuming and pour on the environment. Production using pyrolysis spends a lot of heat in the process of selection of the product, so there is an opportunity to significantly improve the technical and economic performance using plasma process, but these measures have not been ever brought in real life. If we consider the process of production of reactive acetylene gas using dimethylformamide, it is certain that a large amount of dimethylformamide can spend to achieve the level of concentration in the reaction of acetylene gas. Only the following reasons, the quality of the incoming gas mixture can vary significantly. In this regard, we seek such factors by which the process will be more meet feasibility requirements and reduce the impact on the environment.
The manufacture of acetylene gas from the reaction gases is designed to produce high quality acetylene by mass transfer processes taking place in absorbers.
The process of mass transfer in the absorber is one of the most important steps in being saturated with acetylene production cycle. Production of acetylene from the reaction gas is the most economical way of obtaining acetylene because all unused products in the process of returning to a pure storage, where they can be used again in the process. The research on real objects is expensive, very difficult and dangerous, so this improvement is relevant and necessary.
To solve the problems of design of process equipment, synthesis and study of control systems the challenge of obtaining the mathematical model of the process object that best reproduce the properties of real prototype to a wide range of operation. For this purpose, a mathematical model is needed, which would most closely corresponds to the actual and also based on the complexity of the device and the usage of simplifications, which could be neglected .
Today we know a few models of packed absorbers, including regression models and mathematical models are based on the theory of fuzzy logic and fuzzy set theory. However, most of them do not allow simulating the dynamics of the process, and thus make it impossible to optimize dynamic processes.
Исследовано влияние пероксида водорода на волокнистые полуфабрикаты, полученные из соломы рапса нейтрально-сульфитным способом. Изучено влияние расхода пероксида водорода и степени делигнификации исходной целлюлозы на белизну и показатели качества белёной целлюлозы. Проанализированы химические и механические потери волокна в процессе пероксидной отбелки недеревесного сырья.
Исследовано использование отбеленной рапсовой целлюлозы в композиции с белёной сульфитной хвойной целлюлозой для получения офсетной и писчей бумаги. Показано, что увеличение доли рапсовой целлюлозы в бумаге повышает однородность, плотность, непрозрачность, что обеспечивает хорошие печатные свойства такой бумаге. Установлено оптимальные соотношения в композиции бумаг отбеленной рапсовой и сульфитной хвойной целлюлозы без снижения показателей качества.
Робота присвячена визначенню фізико-хімічних властивостей поверхні сорбенту (питомої площі поверхні, питомої густини кислотних та основних активних центрів), оскільки ці параметри є визначальними для ефективного вилучення важких металів зі стічних вод. Об’єктами досліджень були немодифікована та оброблена розчином карбаміду соснова тирса. Установлено, що після оброблення карбамідом питома площа поверхні тирси збільшилася на 35 %. Визначено, що кількість поверхневих карбоксильних груп зменшилася, лактонних – не змінилася, а відносна кількість фенольних груп значно зросла та з’явилися оснóвні групи, що є додатковими активними центрами сорбції.
The main goal of the paper was to determine physicochemical properties of sorbents surface (specific surface area, the specific density of the acid and alkaline active centers) as they pay significant role in the effectiveness of water treatment process. The non-modified and modified by carbamide solution pine sawdust were the objects of the study.
Determining of the surface of functional groups, with the presence of background electrolyte 0.1M NaNO3 to remain the constant value of the ionic power of solution, by acidic-alkali titration among temperature 20˚C the suspension of modified and non-modified pine sawdust were conducted.
The value of specific surface area for modified and non-modified pine sawdust was determined from adsorption isotherm of methylene blue and constituted respectively
The water suspensions of modified and non-modified pine sawdust were titrated and the results were processed in the ProtoFit software. Best results while modelling 3-acidic active centres in case of non-modified sawdust and
3-acidic and 1-alkali active centers, which are able to participate in proton exchange reactions in case of modified sawdust, were achieved.
The improvement of sorption properties of pine sawdust after treatment by carbamide solution may be explained by changes of physical-chemical properties of its surface, namely, due to the formation of additional nitrogen-containing active sites, revealing alkaline properties at titration by acid.
To sum up this paper, as a result of treatment by carbamide, the specific surface area increased at 35 %. Also, it was investigated by the acid-base titration followed by mathematical processing that quantity of surface carboxylic groups decreased, the quantity of lactonic groups was constant, while relative concentration of phenol acid groups increased and basic groups, which are the active centers of sorption of heavy metals, appeared.
Досліджено вплив діаметра гранул, температури та тривалості сушіння на динаміку зміни вологовмісту ПЕТ-грануляту. Запропоновано регресійну модель сушіння у вигляді степеневої функції.
Polyethyleneterephtalate (PET) is one of the most mass polymeric materials which are used for domestic and technical aims. Sixty year history of development of production of polymeric materials on the basis of PET includes development of both methods of processing of fusions polymer directly after a synthesis and through the stage of receipt of granulate. Presently anymore 80 % wares on the basis of this polymer make granulation with the use of the stage.
Apparatus registration of drying of granulate is on enterprises which produce different wares on the basis of PAT, very various, but it is mainly realized in the vehicles of continuous action. Thus there is structural alteration of polymer which accompanies the deep (to 0,005 %) moving away of moisture from it that predetermines stability of further technological process. In this connection systematic studies of aspects of continuous drying of granulate of different size and development on this basis of corresponding recommendations are actual tasks.
In this article results of experimental researches of drying PET-granulate are considered. The influence of pellet diameter, temperature and time of drying are researched. Mathematical model is indicated adequate to the process of drying.
Розроблено математичну модель біогазового перероблення відходів паперового паковання, одержано її аналітичний розв’язок. Наведено теоретичні та експериментальні залежності кількості виділеного біогазу від тривалості перероблення за різних температур субстрату, за сталих концентраціях сухих речовин й ферменту та результати перевірки їх адекватності.
One of the main objectives of developed countries is rational and economical use of energy. Despite the low development level of renewable energy today and disadvantages of energy strategy, Ukraine has good preconditions for further development of renewable energy and in particular bioenergy. Hundreds of tons of waste paper packaging are annually produced in Ukraine. Time of decomposition of paper packaging is from 1 to 400 years in the case of exclusion of film and foil lamination. Biogas released as a result methane fermentation of any organic matter. Therefore, studies to solve this problem by recycling paper packaging by means of fermentation and fermentation anaerobic fermentation in biofuels is important.
Biogas – is a product of metabolism as a result of Vital Functions many groups of organisms of bacterias, that is a mixture of gaseous substances obtained by anaerobic, namely without air, and methane fermentation of organic matter. This mixture consists of approximately 65 % methane, 30 % carbon dioxide, hydrogen sulfide and 1 % minor impurities of nitrogen, oxygen, hydrogen and carbon monoxide. Regularities of methane fermentation process is extremely complex and depends on many factors, the most important of which are temperature, pH and concentration of dry matter.
Highlight the four most important stages, namely: hydrolysis, acidogenesis or biological oxidation or acetogenesis or acid fermentation and the last stage, methanogenesis, at this stage 90 % methane is synthesized, 70 % of which comes from acetic acid.
Among the technological parameters on the speed decoupling most valuable impact is the temperature of the substrate, for her, there are three modes, each of which has the speed of substrate cleavage and the speed of biogas. Temperature is the main parameter in terms of research and process optimization for the temperature regimes.
The aim of this article is analytical research of the kinetics of the concentration field of the liquid and gas phases in bioreactors operating without stirring.
Developed a mathematical model of the biogas process of recycling waste of paper packaging, the analytical solution of a mathematical model for a given initial and boundary conditions, which provides new biogas dependence of selected depending on the time and temperature at a given solids concentration and amount of enzyme.
In order to conduct a pilot study to confirm the adequacy of dependency, the analytical solution of the mathematical model developed laboratory setup consisting of insulated bioreactors periodic operation and the gas container, which are interconnected.
From Dependence found that most slow release biogas process takes place at a temperature of 20 оС, the maximum rate is observed at 50 оС. However, the specific biogas yield at different temperatures remains the same, changing only the rate of release of biogas.
Analysis of the theoretical and experimental dependences shows that temperature influences the rate of biogas yields during biochemical processing of laminated paper packaging. A mathematical model with sufficient accuracy describes the kinetics of the process at different temperatures of the substrate.
Adequate theoretical dependences experimental data was checked and confirmed by the Fisher criterion.
Досліджено вплив двооксиду хлору, пероксиду водню й хлору на вихід, вміст залишкового лігніну, a-целюлози, в’язкість, зольність і білість натронної лляної целюлози для хімічної переробки. Установлено, що одностадійне оброблення лляної целюлози з витратою двооксиду хлору 0,4...0,5 % і пероксиду водню 2...3 % від маси абсолютно сухої целюлози є ефективнішою, аніж оброблення хлорною водою з витратами хлору 3…4 % від маси абсолютно сухої целюлози із подальшим лужним обробленням, оскільки сприяє кращому видаленню лігніну зі збереженням вмісту a-целюлози і незначному зменшенню в’язкості, а також підвищенню білості целюлози вдвічі.
The paper studies the impact of bleaching chemicals such as chlorine dioxide, hydrogen peroxide and chlorine on the product yield, residual lignin content, a-cellulose, viscosity, ash content and whiteness of flax natron cellulose for chemical processing.
It was found that one-step processing of flax pulp with chlorine dioxide consumption rate 0,3…0,5 % and with hydrogen peroxide consumption rate 2…3 % by weight of abs. dry cellulose is more effective than treatment with chlorine water at chlorine consumption rate 3 ... 4 % by weight of abs. dry cellulose followed by alkaline extraction because it provides better removal of lignin, the retaining of a-cellulose and slight decrease of viscosity as well as and increase pulp brightness as much as twice compared to unbleached pulp.
Доведено, що стебла соняшнику і свербіги східної можна переробити лужно-сульфітно-спиртовою делігніфікацією у волокнисті напівфабрикати (ВНФ), які за фізико-механічними показниками наближаються до технічної целюлози з листяних порід деревини. Одержано залежності показників якості ВНФ від температури й тривалості делігніфікації.
Stems of Helianthus annuus and Bunias can be processed into semi-finished fiber products using alkaline sulfite-alcohol delignification. These semi-finished fiber products in their physical and mechanical characteristics are similar to those of the pulp of hardwood. The dependences of quality semi-finished fiber products on the temperature and duration of delignification are obtained.
Проаналізовано переваги та недоліки, джерела сировини, технологію виробництва та застосування біодизельного палива. Надано рекомендації щодо розвитку біопаливної галузі в Україні.
Biodiesel has several advantages compared with conventional fuels, both environmental and operational. But these benefits should not be offset by the potential negative environmental impacts associated with land use or improper use of obsolete technologies.
Biodiesel is not a panacea for energy diseases. Its implementation requires solving a number of problems: biodiesel are usually made from plant material, the scope of which is limited to the needs of the food industry; use of energy efficient technologies is not enough until you can reduce high compared to conventional fuel production cost of biofuel; due to the presence of oxygen biofuel has less energy consumption than its hydrocarbon analogs, which affects the efficiency of its use and performance; application does not guarantee biofuels reduce emissions of toxic gases; any biofuel enjoys limited support from consumers (because its operational and economic characteristics need to be improved), car manufacturers (which is primarily concerned about its corrosivity), and oil refiners (see it as a opponent).
In addition, biofuels is the same finite resource, like oil, because during its production is consumed (often – irreversibly) the fertility of agricultural land. Therefore grown in our country, the raw material for the production of biofuels should be directed primarily to the needs of Ukrainian consumers, and the task of the state – contribute to this.
For sustainable biofuels industry in Ukraine need a coherent and systematic plan of action aimed at least ten years. According to the authors, it would be advisable to do the following steps to complete the following areas: fiscal and regulatory support, regional development, infrastructure development, environmental sustainability, information and education.
Зі змивів з активованого вугілля виділено та охарактеризовано три найпоширеніші спорові бактеріальні культури, що можуть відігравати вирішальну роль в утворенні біоплівки у вугільному фільтрі під час доочищення води, яку використовують у виробництві пива.
When using the sorption coal filters for treatment and advanced water treatment, a biofilm – aggregate of contamination particles, microbial cells and the products of their metabolism – is formed on the coal surface. The named particles are attached to each other and enclosed in a matrix of their extracellular polymeric synthesized compounds. Such community of microorganism has the changed phenotype which is occurred in other parameters of growth, a reproduction speed and an expression of specific genes. A uniform genetic system is established in a biofilm in the form of plasmids which define social behavior of microorganisms. The coordinated activity of microbes’ community makes biofilms to be low-vulnerable to disinfectants and factors of macro-organism protection, and the removal of the film from any surface becomes a challenging task. Therefore over time, there is a need in filters flushing for the biofilms removal in order to restore the filter effectiveness and to prevent secondary contamination of purifying water as it can be dangerous to human health. The study of morphologic-cultural and physiological-biochemical properties of bacteria forming a film is necessary for the development of rational methods of filters cleaning and the improvement of the quality of treated water.
The paper studies biological features of biofilms at active carbon filters used in industrial process water treatment systems of an enterprise producing special drinks. The three most common bacterial cultures, which can play a key role in the biofilms formation in the carbon filter in advanced water treatment for beer production, have been isolated and characterized from swabs from the activated carbon. All three selected bacterial cultures are identified as members of the genus Bacillus. The obtained data are the basis for the development of more effective methods for a biofilm removal from the activated carbon surface at the industrial filters for the brewing industry, and/or combination temperature sanitation with other technologies.
The present paper studies biological features of biofilms at active carbon filters of water treatment systems for process water at the enterprise of special drinks. Three most common bacterial cultures, which can play a critical role in the formation of biofilms in the carbon filter at water purification used for beer production, were isolated from swabs from the activated carbon and characterized. The obtained data are the basis for the development of more effective methods for the removal of biofilm from the surface of the activated carbon filters at the brewing industry, and/or combination of temperature sanitation with other techniques.
Проаналізовано використання сорбентів із магнітними властивостями для очищення водних середовищ від нафтопродуктів і відокремлення частинок магнетиту від очищеної води. Визначено чинники вкливу на дисперсність гранульованого магнетиту й вивчено його сорбційні властивості. Досліджено вплив швидкості фільтрування на ефективність сорбції нафтопродуктів гранульованим магнетитом.
The article deals with the problems of global hydrosphere pollution by oil and petroleum products. The application of different magnetic sorbents for the removal of petroleum products from water is analyzed. The problem of separation of magnetic particles of sorbents from treated water is discussed. The possibility of using magnetite particles for oil separation from water and simultaneous localization of solid phase in the sorption column in a dynamic mode is investigated. In cases of chemical condensation techniques, very low filtration properties of a media formed with magnetite particles are obtained. The possibility of increasing the dispersion of magnetite particles by extension and different methods of granulation magnetic sorbents has been studied. A number of factors affect the dispersion of granular magnetite. Particle size distribution of the suspension is influenced by the concentration of the initial solution. A significant impact of synthesis and thawing temperatures on the size distribution of magnetite slurry has been observed. The graphs, illustrating the effect of concentration of initial components and different thawing temperatures on a variety of granular magnetite particles used as a filter media for sorption filters, have been presented. The influence of freezing/thawing temperature on size distribution of granular magnetite has been investigated. A sorbent based on granular magnetite with satisfactory filtration properties has been obtained. The absorption properties of granular magnetite have been studied. It was defined that despite the lower dispersion of magnetite particles after freezing, its absorption properties were better than conventional magnetite. The maximum sorption capacity to oil products has been determined for traditional and granulated by freezing magnetite. It is shown that the curves of sorption for both types of magnetite are characterized by relatively clear and steep slope. It is concluded that the absorption properties of granular magnetite allow the application of the studied sorbent for treatment of industrial water, polluted by oil and petroleum products. The impact of filtration rate using filtration and sorption systems operating in dynamic mode has been analyzed. It has been determined an optimal flow rate of contaminated water and relations between the filtration rate and oil sorption effectiveness of granular magnetite. The influence of the height of the layer of granular magnetite on oil removal efficiency of sorption filters has been defined. Even though the freezing and thawing processes in an industrial conditions are costly, the increase of the filter layer thickness or multi-use cleaning system allow to effectively run water treatment at filtration rate appropriate for industrial equipment.
The use of magnetic sorbents for the purification of water environments from oil was analyzed. The problem of separation of magnetite particles from purified water was considered. A number of factors affect the dispersion of granular magnetite. The absorption properties of granular magnetite were studied. The effect of velocity filtering efficiency of oil sorption granular magnetite was defined.
Наведено дослідження кінетики вилуговування Mn, Ni, Cu, Pb, Fe із матеріалів хвостосховищ «Дніпровське» і «Центральний яр». Експерименти з вилуговування важких металів проводили за методикою визначення швидкості вилуговування радіонуклідів із радіоактивних відходів (ГОСТ 29114-91). За отриманими даними обчислили константи швидкості вилуговування важких металів із твердої матриці та константи їх виходу у розчин.
Mining and processing of uranium ores associated with many environmental problems. Along with the pollution of natural radionuclides environment, waste tailings uranium processing industry is also a source of contamination of ground and surface waters with heavy metals. Tailing waste on processing of uranium former «Prydniprovsky chemical plant» studied only in terms of distribution and migration ability of radionuclides. Any data on migration ability of heavy metals, but their content in the solid phase of waste and natural waters is not available.
Purpose of work is study the kinetics of leaching of metals from tailings materials industry in uranium processing.
In this paper deals with the kinetics of leaching of Mn, Ni, Cu, Pb, Fe material from tailing «Dneprovske» and «Central yar» Experiment with the leaching of heavy metals was carried out by the method of determining the rate of leaching of radionuclides from radioactive waste (GOST 29114-91). From the data obtained were calculated rate constant leaching of heavy metals from a solid matrix and constant release of their solution.
The results showed that the rate of leaching of heavy metals from tailings samples «Central yar» is almost an order of magnitude higher than samples from tailings «Dniprovske». This can be caused by several factors, including the first differences of the material composition of waste materials, physical and chemical conditions that occur in the tailing. In particular, the tailings are significantly different for the acid-alkaline conditions: the tailing «Central yar» pH are acidic or weakly acidic region, while in tailing «Dniprovske» – in near neutral or even slightly alkaline in. For the lower horizons of the studied both tailing characteristic are lowest rate of leaching of heavy metals. This is especially noticeable for the sample tailing «Dniprovske» 18,7…19,2 m of depth. This can be explained by the fact that the lowest horizon from which sampling was carried out, is underlain by breeds and contain no technogenic waste. The exception іs the lead (plumbum), which is the lowest rate of leaching tailings sample «Dniprovske» 14,8…15,2 m of depth. In tailing «Central yar» migration ability of metals is decreases in the number Mn > Fe > Pb > Ni > Cu. Such a trend is observed for all samples of the tailings. As for tailing «Dniprovske”, a series of migration ability of heavy metals can be set as follows: Mn > Fe ≈ Pb > Cu. Speed Ni leaching into the solution of tailings material «Dniprovske» significantly decreases with depth compared with other metals, so each patient horizon of the tailing position of nickel in some migration ability of metals will be different. The difference between these two tailings on the migration behavior of nickel can be explained by several factors, which are mainly caused by chemical and mineral composition of waste. Also play an important role physical (porosity, humidity) and water (permeability, swelling, filtration coefficient) properties of rocks contained in the tailing. However, these issues have not been fully addressed and require detailed study.
Вивчено сорбцію іонів міді та йонів твердості на сильнокислотному КУ-2-8 і слабокислотному Lewatit TP-207 катіонітах за динамічних і статичних умов. Показано, що слабокислотний катіоніт має обмінну ємність за іонами міді на рівні сильнокислотного катіоніту. Установлено, що за динамічних умов під час сорбування йонів міді у присутності йонів жорсткості обмінна ємність іонітів за йонами міді зменшується. При цьому більше зниження помічене для сильнокислотного катіоніту та йонів кальцію. За невисоких концентрацій іонів міді іони кальцію менше знижують ємність сильнокислотного катіоніту за іонами міді порівняно із слабокислотним, а за концентрацій понад 100 мг/дм3 більш селективним є слабокислотний катіоніт. Установлено, що сильнокислотний катіоніт ефективно регенерується розчинами хлориду й сульфату натрію, а слабокислотний – соляної кислоти.
The sorbtion processes of copper ions and hardness ions are studied on strong-acid kationite KY-2-8 and low-acid kationite Lewatit TP-207 in dynamic and statistic conditions. It was shown, that low-acid kationit has an exchange capacity toe copper ions of at the level similar to strong-acid kationite. It is determined that in dynamic conditions the sorption of copper ions is declined in presence of hardness ions. Greater decline is observed in case of strong-acid kationite compared to low-acid one; calcium ions reduce exchange capacity to larger extent compared to magnesium ions. As derived from the sorption isotherms, at the low concentrations of copper ions, calcium ions reduce the capacity of strong-acid kationite to copper ions to less extent compared to low-acid one, but at concentration of copper >100 mg/dm3 low-acid kationite is more selective.
The regeneration processes of kationites are studied and it is shown that strong-acid kationite is effectively regenerated by solutions of sodium chloride and sodium sulfate, while low-acid kationit – by muriatic acid solutions.
Розглянуто проблему гідросепарації вторинних полімерів. Розроблено математичну модель процесу, проаналізовано умови занурення полімерів у воду та їх відокремлення від інших твердих побутових відходів.
Hydraulic separation is a way of separating solid waste (MSW) into components with water. The technology is cheaper than incineration, with relatively rapid deployment. With the technology of hydro solid waste can be recycled up to 85 % of unsorted waste, which then will be used to rework both recyclables and organic waste – production of biogas and electricity.
For hydraulic sorting of solid waste using water, which is a natural odor neutralizer. Originally unsorted waste coming into the emergency department, equipped with exhaust fans. They were then passed through a stream of water where organic and inorganic components are separated by gravity regulate water flow.
The purpose of this paper is the problem of sorting waste by hydro polymer material in which plastics are sorted from the total weight of waste by adding air to the water, which changes its density, resulting in getting water-air mixture in which the polymers are not emerges the surface, and begin to settle, as their bulk density greater than the density of the resulting mixture.
Ten years ago, the term hydraulic separation was very new to the vocabulary used in the North American hydronics market. Back then the contemporary topic being discussed and applied was primary/secondary piping. The idea being that several loads, each served by its own secondary circuit and associated circulator, could be connected to a common primary loop, with its own circulator. The «magic» of closely-spaced tees is what prevented the flow rate in any of these circuits from interfering with the flow rate in the others.
In essence, that is what hydraulic separation is: the ability of two or more circulators within the same piping system to simultaneously operate without interfering with each other.
Стаття присвячена отриманню з сульфатної хвойної вибіленої целюлози фільтрувального матеріалу для очищення води від завислих і колоїдних частинок, що обумовлюють її каламутність. Досліджено вплив вмісту лавсанового волокна та клею на основі полівінілового спирту на механічні та експлуатаційні характеристики фільтрувального матеріалу.
This article is devoted to the obtaining of filter material from bleached softwood sulphate pulp for water treatment under increased pressure from suspended solids and colloidal particles, which determine water turbidity, and the evaluation of the filter material properties. The influence of the filter material composition (the content of lavsan fibers and adhesives based on polyvinyl alcohol) as well as surface sizing and the mechanical performance of the filter material. The mechanical strength of the samples was determined by the bursting strength factor. The maximum values of the factor for the samples without surface coatings were obtained at the consumption rate of adhesive 50 % and lavsan 15 % by weight of absolutely dry fiber. Adhesive surface coating can improve bursting strength of the filter material by 66…77 %, and the filter material composition has almost no effect at the growth rate.
The evaluation of the effectiveness (performance characteristics) of the samples was carried out by their selectivity for turbidity and productivity. The investigations were conducted by filtering distilled water, barium sulfate suspension with concentration 4250 mg/dm3, obtained by deposition, and kaolin slurry with concentration of 5000 mg/dm3. The filtration was carried out at increased pressure: from 0.25 to 1.75 atm for samples with no surface coating, from 3 to 4 atm for samples with surface coating. The decrease of performance during filtration with constant pressure was observed for all samples. Samples with the maximal initial performance showed the largest (almost twofold) loss of productivity in the first minutes of filtration. The increasing of the pressure improved the performance while keeping selectivity.
As a result of studies, samples of filter material were obtained, that provided selectivity to suspended and colloidal particles, causing water turbidity, at a level of microfiltration membranes. These materials can be used for rough water treatment or water preconditioning before advanced purification.
Розглянуто процеси екструзійного формування безперервних виробів із термопластичних матеріалів та устатковання для їх реалізації. Проаналізовано проблеми, що виникають під час екструзійного формування, і засобів їх усунення, запропоновано шляхи удосконалення існуючих формувальних пристроїв.
Meeting the needs of geometric complicated articles of plastic is impossible without optimizing design and process parameters of equipment and processes of polymers and compositions with their use. Ultimate parameters of the polymeric and composite production are takes into forming tool.
In the design of the forming equipment we must consider that its working channels can has different geometry and processed material – different hydrodynamic and thermal regimes. All of these parameters bound to change the rheological properties of the processed material.
The aim of the paper is to analyze the main factors that affect the quality of the process of polymer products extrusion forming, and means to eliminate defects in extruded products.
For high speed extrusion the conditions for achieving marginal adhesion strength can be created and defective surface arise as a result of highly turbulence. This phenomenon is predicted to achieve a theoretical or experimentally determined critical shear rate. Typically, this problem can be eliminated by reducing the rate of extrusion, increasing the temperature in the forming extrusion die channels, and by addition of external lubricants into the polymer.
For compensation of these effects a new extrusion die design was proposed, which structural elements can absorb vibrations occurring. Annular extrusion die contains a matrix that forms the outer surface of the polymer product, and mandrel, forms the inner surface of the product and which the input and output parts consists. The output parts of the matrix and mandrel are fixed in the moving part of mandrel support, and creates a channel for the melt flow with the output area, and besides the matrix and the output of the mandrel can move back and forth along the axis relative to the fixed part mandrel support with changing of the channel length for the melt flow. In matrix elastic and damping elements are placed that transmit force from it on the cover. The melt was included in the die, enters in the channel between the output mandrel part and the input part, and forms a pressure drop, which leads to the formation of an axial force that moves the matrix of the original part mandrel and moving parts of the mandrel support relatively fixed part of the mandrel support. The length of the channel increases, and the pressure in the die starts to decrease. Matrix, moving in the axial direction, passes through the efforts of the lid damper that reduces the speed of movement, and the spring that tries to take the matrix to its original position. As the process is continuous, as the matrix of the input part of the mandrel takes reciprocates, thereby absorbing pulsation.
Експериментально досліджено корозійну стійкість покриттів, отриманих плазмовим напилюванням порошку оксиду алюмінію плакованого двошаровими оболонками з титану, алюмінію або міді на сталеву та магнієву основу. Проведена термодинамічна оцінка взаємодії оксиду алюмінію з металевими оболонками при плакуванні. Встановлено вплив плакованих порошків на мікроструктуру та пористість плазмових покриттів і зміну поляризаційного опору під час випробувань в рідких агресивних середовищах.
Corrosion resistance coatings deposited by plasma spraying of alumina powders with clad metal PVD film were studied. Thermodynamical evaluation of the interaction of alumina with titanium and copper in cladding was produced. Possibility of interaction was evaluated assuming that the alumina dissolved in the titanium. The result was defined atomic percentage of oxygen and aluminum in the titanium at temperature of cladding. The influence of clad powders on the microstructure, porosity and polarization resistance of plasma-sprayed coatings during testing in corrosive environments was studied. The corrosion behavior of coating was studied by technique of a polarization change based on the measurement of the current between the two electrodes from the same metal and a coating when applied the polarization less than 20 mV.
Alumina powder for plasma spraying coated dual layer of titanium, aluminum or copper reduces the total porosity and improves in a 2–3 times the corrosion resistance of coated steel in 10 % solution H2SO4, HNO3 as well as more than an order of corrosion resistance of magnesium alloy in a 3 % NaCl solution.
Largest values at spraying on steel substrate of the polarization resistance in acid solutions respond coatings from alumina powder with dual layer clad PVD film of titanium and copper. This increase in the corrosion resistance depends more on the thickness of the top sprayed coating than to the material and thickness of sprayed underlayer. It is associated with a decrease in the amount connected pores. Largest values at spraying on the magnesium alloy of the polarization resistance in 3 % NaCl solution had coating on base of clad alumina powder with underlayer and the additional activation of the substrate surface by electrospark doping for improving adhesion strength.
Further research perspectives are to enhance materials for clad powders and more detailed studying of the corrosion damage mechanism at elevated temperatures of plasma-sprayed coatings from clad powders.
Наведено результати експериментальних досліджень двостадійного термоусідання поліпропіленової термоусадної плівки. Визначено залежності коефіцієнта усідання поліпропіленової плівки в поперечному та поздовжньому напрямках від температури. Порівняно одно- і двостадійне термоусідання.
Shrinkage called polymer films capable to contract under the influence of a temperature exceeding the softening temperature of the polymer. Different polymers have different properties at shrink, among which the most important is the shrink degree (shrink coefficient) and shrink stress. Shrink coefficient determines the multiplicity of reducing the linear dimensions shrink film, so that it gets the ability to tightly encircle the products subject to packaging, reproducing its outer contours.
The process of packaging products in shrink film consists of two phases: formation package by sealing it in shrink film; shrinkage of the film through its blowing hot air. Hot air is blowing of package realizing by heat chamber or by heat tunnel.
The aim of the paper is to investigate the shrink coefficient polypropylene film in the transverse and longitudinal directions, depending on the process temperature.
During the implementation of the shrink method in case the object is subjected packing, sharp transitions or sharp edges possible undesirable deformation and/or damage to the object itself, or injury (up to fracture) packaging film (that is destroying the integrity of the package), it would be appropriate to use a two-step incremental shrinkage. Stepwise shrinkage was carried out in two stages: the first stage of the film was in the heat chamber 2 s, and at the next shrink stage – 5 s. In carrying out the experiment was seen addiction at the time that the first shrink stage exceeding 2 s, the relaxation of the film makes it almost fully realized and further shrinkage is negligible. After finishing shrinkage processes coefficient determined after the first stage and the overall shrink and total in the transverse and longitudinal directions, depending investigated transverse and longitudinal coefficients shrink temperature.
A comparison of the experimentally obtained graph of the one-step and two-step in shrink follows that when shrink film at one stage, shrink ratio is increasing with increasing operating temperature, whereas the two-stage shrink biggest factor shrink was obtained at a temperature 170oC . The total shrink degree in two-stage process is almost the same as in the one-step shrink.
Розглянуто задачу статичної оптимізації зневоднення та гранулювання мінеральних добрив у псевдозрідженому шарі за квадратичним критерієм якості. Одержано оптимальні значення витрат вихідного розчину й теплоносія – повітря.
Commercial operation of pellet fluidized bed shows that the reliable operation of such a technological system affects a large number of factors. Their impact on the stability of a technological system for the production of fertilizers with desired properties is still not investigated in full. Despite the fact that some production work for over 25 years, the optimal regime of granulation and drying processes to be found.
The aim of the paper is to investigate the process of obtaining continuous granulated product of a given dispersion composition. The results of static optimization of the process of dehydration and granulation with water solutions of ammonium sulfate using fluid bed granulator are considered.
There are many approaches to the optimization problem. Given the nature of the process optimization is feasible by changing the air flow and discharge of the product from the apparatus to maintain a given pressure drop in the reservoir. Chance of a different formulation of the optimization problem is show. It is proposed to consider air flow control actions and the cost of the initial solution.
In the analysis of processes involving phase transition, in terms of optimization, a material effect on the kinetics of the process with energy performance. Minimizing temperature deviation layer and spending power to carry out the process, was chosen as a quadratic criterion.
The application of static optimization by quadratic quality criterion to determine the effect of temperature on energy efficient process parameters is considered. To ensure the sustainability of the load for a working solution must adequately increase the temperature of the coolant at the inlet to the machine. Increasing the mass flow of liquid agent – coolant spending limit at which the rate of coolant in the machine is equal to the minimum rate of removal of particles.
Solution of the problem connected static optimization by quadratic quality criterion. Temperature dependence of the layer of control actions showed the presence of pronounced local minima. Optimum values of the original cost of the solution and coolant – air.
Проаналізовано практичне застосування розроблених енергоефективних технологічних засад одержання препрегів для базових процесів їх одержання, а саме змішування, просочування волокнистих наповнювачів та дозованого нанесення на них епоксидних зв’язуючих, із використанням ультразвуку.
It was stated that the basic processes of impregnation and dosed application are the important parts of the production of prepreg for polymer composite materials (PCM). This is because the quality of the impregnation is influenced by such factors as the presence or absence of air inclusions (so-called "bottle effect") in the structure of the impregnated fibrous filler during its impregnation, the homogeneity and the viscosity of the polymeric binder, good surface wettability of fibrous filler and so on.
The essence of the developed energy-efficient technological foundations is based on the integrated use of ultrasonic for the basic processes of manufacture of prepregs to overcome the above said drawbacks in their preparation.
Studies have shown that the effective effect of ultrasonichelps to improve the homogenization of the polymer binder, activation of fiberfill surface to improve its wettability with the polymer binder drainage structures fiberfill right before impregnation and to increase the productivity of the process of impregnation and dosed application of polymer binder by increasing the speed of a fiber-fill drawing with improving of properties of the final solidified PCM.
Furthermore, it was found out that the use of ultrasonic exposure to the impregnated fibrous filler in the bath and also to already impregnated fibrous filler may be regarded as an effective method for automatically maintaining of the required amount of containing of the binder polymer in the impregnated fibrous filler.
In addition, due to the action of ultrasonic reduces cumulative time of receipt of the prepregs, which ultimately also contributes to energy saving in the preparation of prepregs.
The result of the application of the developed technological bases and the equipment is the increase of productivity of the impregnation processes and dosed application of polymer binder, i.e. speed of drawing of the material and speed of removal of excess polymer binder in the preparation of a homogeneous impregnated material with virtually no air pockets.
This allows recommending the developed new technological basis of three-stage ultrasonic processing and the necessary equipment as a reliable means to maintain a predetermined value of the quantity (stabilization) of content of the polymer binder impregnated fabric filler.
A number of case studies (including the use of impregnation-drying machine MPT-3M) with the developed technological bases and equipment, providing energy saving process of preparing a polymer binder, impregnating a fibrous filler and dosed application to them the polymer matrix using ultrasonic was studied.
It is noted that with the use of the developed technological bases and equipment is achieved the use of highly viscous and highconcentrated impregnating compositions, and compositions with the disperse filler.
Проведено експериментальне дослідження середньої товщини плівки, гальмівного впливу стінки на рідину в роторно-плівковому апараті з висхідним потоком.
Intensification of heat and mass transfer processes in liquids most simply solved by using thin-film equipment. Organization processes in thin layers of liquid widely used in chemical, biotechnology, food and other industries. The basic requirement for improving the quality of thermally labile substances is to ensure continuity of the film and a small residence time of the product on the heating surface. In rotary apparatus with falling film problem is to ensure continuity of the film, especially in the case of high intensity of evaporation. Organization upward flow in rotor-film devices allows you to create favorable conditions for the processing of thermally labile compounds.
Due to the complexity of studying hydrodynamics upward flow in a rotor-tape machine can not only describe the process of theoretical functional dependencies. Experimental studies provide an opportunity to present their results in the form of empirical equations that reflect the real picture of the process.
One of the main parameters characterizing the hydrodynamics of rising film flow is pumping and the average thickness of the film. The results of experimental studies for the height dependence of the number of revolutions of the rotor and the volume of fluid in the apparatus are based on the inhibitory influence of the wall. Also, the average film thickness is depending on the number of revolutions of the rotor and the fluid flow.
The study was carried out on a glass model of rotary-film device with a transparent wall , the height of discharge (235 mm) rotor with rigid blades, adjustable blade number (2 to 6) and the gap between the blades and the wall (0.75…2.00 mm). Experiments were carried out during isothermal upward flow of water at a temperature of 18 °C. Number of blades was 6, the distance between the blade and the wall – 2 mm. Rotor speed was changed from 30 to 100 rad/s.
It was established that the ratio of inhibitory effect increases with the amount of fluid that is in the machine, and decreases with increasing angular velocity. The thickness of the film increased with the flow and decreases with increasing angular velocity. The results are summarized relevant equations. Calculated values differ from the experimental values of less than 5 %. Reliability approximations made 0.96, indicating a sufficient reproducibility.
The results can be used for design calculations and further research rotary-film devices with a rising film.
Повідомляються результати досліджень із встановлення оптимальних технологічних параметрів спікання інструментальних композитів з надтвердих матеріалів із мінімально можливою щільністю потужності і максимально можливими швидкостями руху лазерного випромінювання відносно дослідного зразка.
Optimal technological parameters of laser sintering with the aim to minimize laser beam power density and to maximize travel speed of laser beam or workpiece for the formation of cutting tools from super-hard composites were determined in this paper.
Використовуючи експериментальні дані про електропровідність сипкого коксу та графітованих сумішей, одержано залежності, що дозволяють визначати питомий електричний опір залежно від вмісту сирого й графітованого коксу в суміші в діапазоні температур від 20 до 1000 °С, а також питомого електричного опору для сирого коксу й графітованої суміші залежно від її гранулометричного складу.
Using previously obtained experimental data on the electrical conductivity of bulk (carbon) coke and graphite mixtures obtained relationships to determine the value of specific electric resistance depending on the composition of crude coke and graphite in a mixture in the temperature range from 20 to 1000 °C. Also dependence of the electric support for raw coke and graphite convertible mixture depending on its grain size is obtained.
Study of the electrical resistivity of carbon materials relates to the field of saving energy in the furnaces of graphitization. Carbon materials are not only the raw materials for electrode manufacturing and coal products, but also are the active electrical resistivity in the furnaces of graphitization and can be recovery and thermal insulation. Resistance value allows drawing conclusions on the structural transformations that took place in the carbon material, caused by external influences on him. Electrical resistivity of the coal charge exhibits a significant influence on the uniformity of distribution of electric power in the volume of the furnace and has a direct impact on product quality and losses of energy.
Literature data of electrical resistivity of the coal charge can’t be used without additional analysis and calculations in different technological process conditions. The reason for this is the dependence of properties coal charge not only on the temperature range, but also on the particle size distribution of the starting materials and the degree of graphitization.
The article draws previously obtained experimental data on the electrical conductivity of particulate coke and graphite mixtures. Analysis of the experimental data showed that for the materials in question observed correlation of electrical resistivity particulate carbon materials on the particle size and the degree of graphitization.
The results of our study allow defining the magnitude of the electrical resistance depending on the composition of the mixture of raw coke and graphitized, the particle size of the starting components of the mixture at temperatures ranging from 20 to 1000 ºC.
The obtained dependences are necessary to find the optimal properties of the coal charge used in the production, as well as for the development of energy-saving regulations in technological processes of the enterprises.
Наведено результати досліджень впливу температурного поля скловарної печі на показники якості скловиробів. Одержані кореляційні функції, котрі показують зв'язок між характерними температурними точками у печі, в котрих розташовані термопари, та основними показниками якості скловиробів. На основі даних кореляційних функцій визначено точку вимірювання температури котра є визначальною для основних показників якості.
Results of studying the temperature field effect on glass products quality factors are provided. Correlation functions that show relationship between furnace’s characteristic temperature spots with thermocouples installed and the main quality factors of glass products are received. Temperature measurement spot which defines the quality factors of glass products is found based on the correlation functions.