The paper concentrates on three major items: it gives a review of in situ remediation methods using low-or high-freguency electric currents for heat transmission into the soil,present examples of pilot-scale applications of 60Hz current and radio-frequency radiation to soil cleanup, and discusses the results of laboratory investigations into the remediation of contaminated sand and soil.In the laboratory experiments,electric or electromagnetic energy was supplied to the soil through antennas or electrodes located at the contaminated place.The quantity of the energy absorbed by the soil depended strongly on the dielectric parameters of the aqueous medium,on the mineral components of the sil,and on the contaminants present there.Conversion of radiation of electricity into heat was concomitant with a rise in temperature.When power-line-frequency currents were applied,the process unitized the mechanism of the Joule effect and the principle of ohmic heating. When radiowaves and microwaves were involed,the process followed the mechanism of dielectric heating-simular to the one occuring in microwave ovens.The rise in soil temperature resulted in the desorption or evoporation of organic contaminants into the soil air at a rate which depended on the temperature of the soil.Laboratiry experiments substantiated the utility of microwave heating in the redendiation of contaminated soil.Compared to other remediating methods,microwave heating runs at a very fast rate,yielding high removal of volatile and semi-volatile organics,especially polar contaminants. In the presence of water,the removal of polar and non-polar substances can be described in terms of the steam distillation principle.The cleanup process then runs under steady styate conditions,at a temperature which does not exceed 100 o C. The is of particular importance of the cleanup of organic soil,because overly high temperature may burn the humic substances up.
W artykule przedstawiono wyniki badań suszenia sublimacyjnego wybranych produktów spożywczych. Określono rozkłady temperatury w czasie na powierzchni próbek oraz ich wnętrzu. Mierzono również w sposób ciągły ubytek wilgoci w suszonych materiałach w trakcie procesu. Wyznaczono zależności szybkości suszenia od czasu dla badanych próbek.
EN
This papier presents results of investigations on freeze-drying of selected food products. Distributions of temperature vs time have been determined for both surface of sample as well as inside them. Continuous measurements of moisture decrease in drying materials have been determined for the investigated products.
W artykule zawarto opis podstaw fizykochemicznych oraz zastosowania suszenia sublimacyjnego. Przedstawiono również przegląd literatury dotyczącej najnowszych osiągnięć w tej dziedzinie, w tym głównie sposobów dostarczania ciepła do suszonego materiału, sposobów kondensacji pary wodnej oraz metod wstępnego zamrażania surowca. Omówiono również nowoczesne rozwiązania aparaturowe do suszenia sublimacyjnego.
EN
The paper describes physico-chemical fundamentals of Freeze-Drying process as well as its application. A review of literature dealing with new achievements in the subject, especially methods of heat supplying to dried material, methods of steam condensation and preliminary freezing of material is presented too. The authors discussed design of modern apparatus used in Freeze-Drying.
Przedstawiono wyniki badań procesu suszenia fluidalnego nasion rzepaku z wykorzystaniem ogrzewania mikrofalowego, w których posługiwano się specjalnie skonstruowaną laboratoryjną aparaturą badawczą. Określono wpływ takich czynników, jak moc mikrofal, wilgotność początkowa materiału, natężenie i temperatura powietrza unoszącego złoże na przebieg i wydajność procesu suszenia. Oszacowano rzeczywistą ilość energii mikrofalowej zaabsorbowaną przez materiał w poszczególnych etapach suszenia.
EN
The results of experiments on the process of fluid-bed drying the rape seeds with microwave heating are presented. In the experiments, especially constructed laboratory fluid-bed microwave dryer was used. The influence of such parameters as microwave power, initial moisture content in dried material, velocity and temperature of air on the drying process was discussed. The results of estimating the actual microwave power absorbed by the material in each part of the drying are also presented.
Soil and groundwater contamination by petroleum hydrocarbons and organic solvents has become a worldwide problem, which primarily faces high-technology countries. Soil vapor extraction (SVE) of volatile and some semivolatile compounds is rapidly being recognized as a technically and economically sound alternative to the available methods of cleaning chemically polluted soils. SVE entails the induction of an advective air phase through the contaminated vadose zone of the soil. In the unsaturated zone, the air flow can be established with combinations of withdrawal (extraction) and injection (if required) wells. Air laden with the contaminant vapors moves along the induced flow paths toward the withdrawing system, where it is subject to after-treatment. If the process is carried out for a sufficiently long time, it will be possible to remove all of the contaminants from the soil. The use of the SVE method provides continuous air flow through the vadose zone, which is a requisite for an efficient cleaning operation. A reliable assessment of the pressure distributions in the vicinity of the extraction wells, and a thorough analysis of the air flow conditions are of great importance to the design of an optimal SVE system, as well as to the determination of the major operating parameters. The present paper describes a three dimensional mathematical model which predicts the steady-state air flow through the unsaturated zone of the soil. The paper also includes the results of a computer simulation of air flow in soils, using the AIR3D software developed by loss and Baehr. With this software it was possible to examine how the properties of the soil (porosity, permeability and anisotropy) and the operating parameters of the SVE system (number and arrangement of the wells, depth and length of the filters, vacuum head in the wells) affect the pressure distribution, the mass and volumetric air flow rate, as well as the components of the air velocity vector in the soil.
Desorpcja próżniowa zanieczyszczeń z gruntu (ang. skrót SVE) jest jedną z najpopularniejszych metod oczyszczania gruntów zanieczyszczonych substancjami ropopochodnymi. W opisie matematycznym procesu najistotniejszymi zagadnieniami są transport i wymiana masy wewnątrz środowiska gruntowego. W pracy przedstawiono model matematyczny wymiany masy zachodzącej w gruncie.
EN
Soil Vapor Extraction is one of most popular methods of remediation of contaminated soils from petroleum hydrocarbons. The most important task in mathematical modeling of SVE are mass transport and transfer inside the soil.s environment. The mathematical model of mass transfer in the ground was worked out in the paper.
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