Thermophysical Properties of Materials
Thermal, X-ray diffraction, and kinetic characteristics of filtration films in the study of ethereal substances
S. I. Lazareva,
Yu. M. Golovina,
S. V. Kovalevba, D. N. Konovalov
a, S. I. Kotenev
a a Tambov State Technical University
b Tambov State University named after G.R. Derzhavin
Abstract:
This paper presents the results of the evolution of the structure of filtration films of the MFFC-
$3$ and PP-
$190$ types in the process of purification of ethereal substances. It has been established by thermogravimetry that a decrease in the mass of samples of working films for MFPC-
$3$ by
$\sim22\%$, and for PP-
$190$ by
$18\%$, which is a at temperatures of
$\sim130$–
$265^{\circ}$C, is due to the destruction of the polymer molecules of the drainage layer as a result of transmembrane pressure and diffusion of ethereal substances. For a pure MFFC-
$3$ membrane sample, a single thermal effect is recorded at the peak melting temperature
$T_{\text{max}} = 247^{\circ}$Ñ, typical for lavsan with melting enthalpy
$\Delta H = 40$ kJ/kg, and for the working sample at
$T_{\text{max}} = 249^{\circ}$C with
$\Delta H = 19$ kJ/kg. For a clean sample of the pre-filter PP-
$190$, a single thermal effect is recorded at the peak melting temperature
$T_{\text{max}} = 160^{\circ}$C with
$\Delta H = 68$ kJ/kg, and for the working sample at
$T_{\text{max}} = 157^{\circ}$C with
$\Delta H = 67$ kJ/kg. The bulk crystallinity of the MFFC-
$3$ and PP-
$190$ films of the working samples decreased by
$52$ and
$33\%$, respectively, in relation to the initial ones, according to the data of differential scanning calorimetry. X-ray diffraction data indicate changes in the microstructure of films of working samples in the intergranular amorphous phase as a result of deformation of lamellar crystallites, while the X-ray degree of crystallinity of the MFPC-
$3$ film decreased by
$12\%$, and that of PP-
$190$ by
$9\%$. On the dependence curves of the hydrodynamic permeability of MFFC-
$3$ and PP-
$190$ filtration films on time at different transmembrane pressures, four characteristic periods are noted, where gel clots are formed on the MFFC-
$3$ membrane, which significantly affect the process of baromembrane separation and the PP-
$190$ pre-filter becomes clogged.
UDC:
66.081.6
Received: 13.05.2021
Revised: 17.09.2021
Accepted: 28.09.2021
DOI:
10.31857/S0040364422030012
Fulltext:
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