scholarly journals INVESTIGATION OF THE INFLUENCE OF MICROWAVE RADIATION ON THE PROPERTIES OF GRANULAR HEAT INSULATION MATERIALS BASED ON LIQUID GLASS

Author(s):  
Tatyana Rymar

The main methods of improving the performance of granular thermal insulationmaterials based on liquid glass are chemical methods of their modification, which are based onchanging their structure through the use of special ingredients. At the same time, there is a need to introduce often a large number of components and individual technological operations, which is notalways technological. One of the promising methods of changing the physical state of substancesunder the action of an electromagnetic field is non-thermal treatment of microwave radiation. Theadvantages of using microwave radiation in comparison with the generally accepted methods ofmodification of materials are the transformation of their structure without significant changes in thetechnological process and the need to use additional components. Due to volumetric heating and themechanism of non-thermal action of microwave radiation on processing objects the duration of theirheating considerably decreases. When microwave heating of a liquid glass composition part of theenergy of electromagnetic radiation is converted into heat, which contributes to the intense swellingof the material, and the other part is aimed at structural changes in the material, which improve itsproperties due to the non-thermal effect of microwave radiation. Studies show that the best set ofperformance properties have granular materials obtained under the action of microwave radiationat a power of 650 W, which corresponds to a temperature of 110-120 0C. The required duration ofsuch heat treatment is 6-7 minutes. The closest to them in terms of coefficient of swelling are materialsobtained by convective heating at a temperature of 200 0C for 1 hour, but their physical andmechanical properties are much lower. Thus, it can be noted that the use of microwave radiationallows to obtain granular thermal insulation materials with a better set of performance properties atlower energy costs for their production.

Author(s):  
Tatyana Rymar

The study of the thermal insulation market of Ukraine showed that the market is dominated by aerated concrete and silicates, which are used as thermal insulation materials at an average density of 300-500 kg / m3. Their disadvantages include high values of water absorption and hygroscopicity, as well as very low flexural strength, because this material does not have elasticity and the use of small bending forces leads to its cracking. Foam glass has a set of operational properties that meet the highest regulatory requirements. Foam glass is the strongest of all effective thermal insulation materials, but this material is fragile. It is sensitive to vibration - induced damage. In addition, the technology of production of foam glass is quite complex and requires high energy consumption, as a consequence, the cost of this material is high. Therefore, it was important to develop thermal insulation material with the appropriate level of performance while reducing production costs. This was achieved by using energy-saving microwave technology to swell liquid glass materials. This technology is based on the simultaneous swelling of the liquid glass granulate and the binder under microwave radiation, which, due to the volumetric heating of the liquid glass composition, allows to obtain a strong monolithic material with a rigid, homogeneous and mostly closed-porous structure. The production of thermal insulation materials is proposed to be carried out on the basis of liquid glass granulate, because the introduction of granules reduces the deformability and shrinkage of the material and prevents its cracking, increases its strength, because the granular material has a certain plastic deformation, reduces water hygroscopicity. granules swell to form a compacted shell, which slows down the absorption kinetics of water and its vapor. The monolithic granules are proposed to be carried out with a binder that foams not only due to the release of water, but also with the help of a gasifier, because this technology will allow uniform distribution of the binder in the intergranular space, thus forming a more homogeneous structure of the material, which has a positive effect on its physical and mechanical characteristics.


Author(s):  
Tatyana Ernstovna Rymar ◽  
Oleksandr Viktorovith Suvorin

Improving the efficiency of energy use is one of the main tasks in the chemical industry not only in Ukraine but also around the world, which is due to the steady rise in energy prices. In this regard, an effective way to save energy is the thermal modernization of buildings, industrial equipment and communications with thermal insulation materials. It should be noted that the share of domestic materials in the Ukrainian market is not more than 30 %. Therefore, the creation of new types of insulation materials is a very important task. This material is a heat–insulating material based on liquid glass, created with the involvement of microwave radiation as an alternative to traditional convective thermal heating. The technology of production of heat–insulating materials on the basis of liquid glass by hot foaming involves obtaining the material in the form of granules, not plates, due to the difficulty of uniform heating of the inner layers of large samples. The problem of large–scale production of high–quality thermal insulation materials based on liquid glass in plate form is not solved due to poor heating of the inner layers of the plate due to the low thermal conductivity of the swollen outer layers. That is why the production of composite thermal insulation materials based on granular filler and liquid glass binder is proposed to be carried out under the action of microwave radiation. Thermal insulation properties of expanded materials are directly determined by their macrostructure. Therefore, the purpose of this study is to determine changes in the structure of the material from the type and amount of ingredients used in the liquid glass composition. On the basis of the conducted researches it is shown that the materials with use as a filler of zinc oxide and as a gas–forming agent of hydrogen peroxide have the most ordered structure. It is established that their use in the amount of 9–10 wt.h. provides a rate of gas evolution and growth of pore centers, which is comparable to the process of curing composition, which allows to obtain materials with a homogeneous, fine and closed–porous structure, which provides high insulating properties with a thermal conductivity coefficient of 0.05–0.055 W / m · K, which meets the requirements for thermal insulation materials.


2018 ◽  
Vol 77 (19) ◽  
pp. 1719-1727
Author(s):  
N. G. Kokodiy ◽  
М. V. Kaydash ◽  
S. V. Pogorelov

2012 ◽  
Vol 9 (1) ◽  
pp. 91-93
Author(s):  
U.R. Ilyasov ◽  
A.V. Dolgushev

The problem of volumetric thermal action on a moist porous medium is considered. Numerical solution, the influence of fluid mobility on the dynamics of the heat and mass transfer process is analyzed. It is established that fluid mobility leads to a softer drying regime. It is shown that in low-permeability media, the fluid can be assumed to be stationary.


1975 ◽  
Vol 97 (2) ◽  
pp. 145-150 ◽  
Author(s):  
J. L. Lauer ◽  
M. E. Peterkin

Interferometry has provided the sensitivity needed for the gathering, through suitable windows, of infrared absorption and emission spectra of excellent resolution (<1 cm−1) from sample volumes even as small as EHD contact regions. Thus the power of molecular vibrational spectroscopy can be used to determine phase changes and structural changes in fluids subjected to conditions prevailing in EHD contacts. In this paper, some of the infrared methods are illustrated by the description of preliminary work in which the cavity of a high-pressure diamond anvil cell was used for contact simulation. Reference is made to a fluorescence-spectroscopic method of pressure determination in the diamond cell, which is also helpful in locating liquid/glass transition points.


Author(s):  
Guram Khitiri ◽  
Raul Kokilashvili ◽  
Tinatin Gabunia ◽  
Madona Tsurtsumia

Hydro-insulation of building constructions, different purpose structures is one of the most important and urgent problems of the present day. Currently concrete, ferroconcrete, metal and wooden materials are used for this purpose. Materials of this kind are not produced in the South Caucasian region. Their import, transportation, clearance by the customs and other expenses significantly increase the cost of buildings and makes it unprofitable to use them. Excreted from petroleum products – paraffins and cerezines, petrolatum, luminophores and various purpose binders, can become profitable basis for obtaining of moderm hydroinsulation materials. Their inclusion in modern hydroinsulation compositions will help to increase quality of these materials and to decrease their cost. By mixing of the goudron obtained as a result of rectification of oil pipeline sediments with milled secondary tyre casting, liquid glass, quarz sand and several additives – new hydroinsulation material was obtained.


1996 ◽  
Vol 53 (10) ◽  
pp. 614-627 ◽  
Author(s):  
Takashi KUSHIDA ◽  
Yasuo KANEMATSU ◽  
Atusi KURITA

2020 ◽  
Vol 24 (6) ◽  
pp. 15-19
Author(s):  
A.V. Kolpakov ◽  
E.S. Abdrakhimova

The possibilities of obtaining porous fillers based on carbonate sludge and liquid-glass composition are considered. One of the issues of industrial waste disposal is the creation of waste-free technologies. The use of nanotechnology-based carbonate sludge in the production of porous aggregates increases environmental safety. A porous aggregate with high physical and mechanical properties was obtained. The use of carbonate sludge in the production of porous aggregate contributes to: a) recycling of industrial waste; b) environmental protection; C) expanding the raw material base for obtaining ceramic materials for construction. A patent of the Russian Federation was obtained for the obtained method of producing a porous aggregate using a liquid-glass composition.


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