Refractory Material Moisture Metering When Heating High-Temperature Units
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Vol. 61, No. 2, July, 2020
REFRACTORY MATERIAL MOISTURE METERING WHEN HEATING HIGH-TEMPERATURE UNITS A. S. Nikiforov,1,2 E. V. Prikhod’ko,1 A. K. Kinzhibekova,1 and A. E. Karmanov1 Translated from Novye Ogneupory, No. 4, pp. 56 – 59, April 2020.
Original article submitted November 30, 2019. The specifics of the drying process of the lining of high-temperature units are described, in particular, the average drying rate is analyzed. The adequacy of the proposed mathematical dependencies is confirmed by comparing the results obtained by calculation, and experimental data obtained at the laboratory bench. The research results can be used to develop a schedule for heating high-temperature units after major repairs to remove moisture. Keywords: refractory materials, drying, high-temperature units (HTU), lining, moisture limit coefficient.
veloped. The complexity lies in the variety of refractory materials used, the various thicknesses and the number of layers of the lining, as well as in the many ways of heating, etc. Thus, in article [4], data are given on the drying of refractory concrete applied using a shotcrete machine and in bulk lining. The diffusion coefficients of these two methods differ by about a factor of 10, while the estimated drying time of the working layer of the lining differs about 5 – 7 times. For this reason, when heating the HTU lining, heating schedules developed by the manufacturer for a particular unit are used, or the rules obtained based on operating experience. HTU drying examples are presented in [5, 6], which describe the drying and heating of HTU according to the schedules provided by the refractory materials manufacturer, and the task of the maintenance personnel was only to adjust the thermal power of the energy source based on the readings of temperature sensors. In both examples, the change in thermal power is automatic; for this, two controllers connected to thermocouples are used with the ability to set upper and lower temperature limits. When the upper limit is reached, a signal is sent to turn off the burner; when the lower limit is reached, the signal turns on the burner [6]. However, even the schedules provided by the manufacturer are not optimal. The main task of the manufacturer is the maximum continuous operation of refractory materials in the HTU. The drying and heating schedules given in this case should avoid the maximum drying speeds. The goal of enterprises operating the HTU, on the contrary, is to reduce the
INTRODUCTION Drying of high-temperature units (HTU) is the removal of moisture (free and chemically bound) from the materials of the lining, which gets into it during the manufacture of materials or during their storage and installation. When the lining is heated, water vapor appears, which is initially contained in the lining materials. This is due to the fact that sudden heating leads to rapid vaporization and steam passing through the gaps in refractory products and softening the seams between them. When drying refractory concrete and ramming masses at high sp
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