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Wybrane aspekty procesu krzepnięcia zachodzącego w wilgotnym złożu granularnym

Partyka Jacek

Inżynieria i Budownictwo

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2024

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R. 80, nr 1-2

36--41

PL

W niniejszej pracy przedstawiono zagadnienia dotyczące procesu krzepnięcia zachodzącego w wilgotnych granularnych ośrodkach porowatych, w których woda w wyniku oddziaływania niskich temperatur podlega przemianie fazowej. Tworząca się warstwa zakrzepła, której objętość jest większa od objętości wody, powoduje uszkodzenie struktury danego ośrodka porowatego. W opracowaniu przedstawiono charakterystykę materiałów porowatych, a także opis i sposób wyznaczenia podstawowych parametrów związanych z krzepnięciem w porowatych złożach granularnych. Ponadto, w ramach analizy teoretycznej procesu krzepnięcia w granularnym złożu, przedstawiono w pracy uproszczony model teoretyczny wilgotnego materiału porowatego, umożliwiający opracowanie odpowiednich wzorów teoretycznych opisujących zjawisko krzepnięcia. W celu weryfikacji teoretycznych rozwiązań problemu przedstawiono opis i budowę stanowiska badawczego do przeprowadzenia badań eksperymentalnych. Wykorzystując zdefiniowane wielkości bezwymiarowe i wzory, szczegółowo przedstawione w pracach innych badaczy, opracowano wykresy i zilustrowano je w pracy. Całość opracowania podsumowano wnioskami, które dotyczą dużego znaczenia praktycznego przedstawionych zagadnień, szczególnie dla stanu technicznego nawierzchni drogowych.

EN

This work presents issues related to the solidification process taking place in moist granular porous media in which water undergoes a phase change as a result of low temperatures. The characteristics of porous materials are also presented, as well as the description and method of determining the basic parameters related to solidification in porous granular deposits. Moreover, as part of the theoretical analysis of the solidification process in a granular bed, a simplified theoretical model of a wet porous material was presented, enabling the development of appropriate theoretical formulas describing the solidification phenomenon. In order to verify the theoretical solutions to the problem, a description and construction of a research stand for conducting experimental research were presented. Using defined dimensionless quantities and formulas, presented in detail in the works of other researchers, charts were developed and illustrated in the work. The entire study is summarized with conclusions that concern the great practical importance of the presented issues, especially for the technical condition of road surfaces.

2

Hydrodynamic and kinetic study of an elution of a high viscosity liquid from the sand bed using eluent of low viscosity

Sęk J., Błaszczyk M., Bartos M.

Chemical and Process Engineering

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2012

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Vol. 33, nr 1

31-41

EN

The study was aimed to determine the hydrodynamic of water seepage through a porous bed saturated with different amounts of high viscosity liquids. An attempt was made to describe the process of seepage through beds saturated with oils using the theory of outflow of a liquid from the tank. It was assumed that the discharge coefficient will represent changes of flow resistance during the process. It was found that the dependence of this factor on time is linear. In the second part of this work kinetics of the seepage process was investigated. Dependence of oil concentrations, eluted from the deposit with the flowing water, on time has been evaluated. Thanks to these studies it was possible to determine the effectiveness of an elution of high viscosity liquids from porous beds using water as the washing out liquid.

3

Aparat hybrydowy ze złożem ziarnistym w instalacji spalania odpadów

Hehlmann J., Pietrasik E., Kujawska E., Bania D.

Rocznik Ochrona Środowiska

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2009

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Tom 11

281-297

EN

Combustion of municipal and industrial waste is widely used method of utilization. However it is accompanied by a number of problems, mainly related to ensuring dequate calorific value and reducing emission of pollutants in the exhaust gas (dust, sulfur dioxide, carbon monoxide, nitrogen oxides, dioxins and PAHs).The designed waste incinerating plants equipped with complex systems of harmful compounds emission reduction, flue gas treatment and disposal of ashes accounts for 75% of the whole incinerating plant capital costs. The way to reduce costs can be a usage of the flue gas heat for drying specially preparated bed. This bed purifies flue gas from the dust and gas components and then undergoes co-combustion with waste, contributing to an increase of calorific value and stabilization of the combustion process. This paper presents potential use of the apparatus with sliding granular bed as a hybrid device for simultaneous removal of solid and gas pollutants from flue gas, as well as skin-drying of the bed. Finding this solution advisible, comprehensive process researches of the gas cleaning, drying and gas pressure drop across model granular beds have been carried out. The laboratory installation enabled measurement of gas cleaning effectiveness, rate of bed drying and gas pressure drop in its variables; flow velocity in the range of w0=<0.1...1>m/s, temperatures t=<90...190>deg. C dust concentration cp=<1...10>ź10-3 kg/m3 and also different parameters of the bed have been used. Based on the collected results, the criterion equations of gas cleaning process, drying and pressure drop for model granular beds have been developed. Research and analysis of the results showed that: 1) the drying of waste prior to their thermal disposal gives the possibility of increasing their calorific value for about 27÷30%, which translates directly into the calorific effect of the boiler, 2) the possibility to obtain the gas cleaning efficiency in the range of 60 to 99.9%. Such solution may be a first stage of dedusting or a final one, depending on the structure of bed, dust and gas properties and selected load of filtration surface as well as the sequences of apparatuses in the line of flue gas treatment from the municipal waste incinerating installation. Developed calculation methods are helpful in designing equipment for the beds drying and waste gases cleaning in the waste disposal process i.e.: in waste incinerating plants, in the plants of formed biofuel production, or when inert beds are used as high performance filter deduster especially in the case of high-temperature gases with recovery of the powdery product (eg. installation of Titanium White).

4

Model dynamiki złoża ziarnistego w granulatorze talerzowym

Heim A., Każmierczak R., Obraniak A.

Inżynieria Chemiczna i Procesowa

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2004

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T. 25, z. 3/2

993-998

PL

W pracy zaproponowano model dynamiki złoża ziarnistego przetwarzanego w granulatorze talerzowym. W wyniku analizy równowagi sił działających na talerz uzyskano zależność między momentem obrotowym a parametrami konstrukcyjno-procesowymi i własnościami granulowanego złoża. Zależność tę zweryfikowano doświadczalnie.

EN

A model of the dynamics of a granular bed processed in a disk granulator is proposed in the study. On the basis of analysis of the equilibrium of forces acting on the disk, a relationship between the moment, apparatus and process parameters and granular bed properties was obtained. The relationship was verifiedexperimentally.