HIGH TEMPERATURE COMPACT CERAMIC REGENERATIVE HEAT EXCHANGER

Abstract

The subject of the research is the high-temperature compact ceramic heat exchanger of a regenerative type with a honeycomb structure. In relation to high-temperature processes of basalt smelting and glass melting, the possibility of its application in a system of high-temperature air combustion is considered. It is noted that heating of the air pursues both energy goal – reduction of natural gas consumption, and technological goal – increasing the amount of free oxygen in the basalt processing zone. The methods of determining the transient temperature field in the wall of the solid heat-storing material of the regenerator and the operating time of the heat exchanger from the condition of ensuring the permissible surface temperature of the heat regenerator are given. It is established that for the range of the Fourier number Fo≤2.5, it is possible not to take into account the temperature distribution in the wall of the solid heat-storing material of the regenerator and to operate with its average temperature. Features of compact ceramic regenerative heat exchangers are given – heat exchanger efficiency, heat recovery coefficient, number of transfer units, power – as applied to the conditions of the heat engineering process. The heat exchanger efficiency is confirmed. The operating time of the heat exchanger and its effect on the surface temperature of the solid heat-storing material are determined. It is shown that in relation to the conditions of the basalt melting and glass melting processes, the material of the regenerative heat exchanger – mullite – is not an optimal solution. Only for one of the considered variants of the technological process, the surface temperature of the regenerative heat exchanger was lower than the permissible temperature of prolonged use of mullite. In other cases, the resulting temperature of the regenerator exceeded the permissible value of long-term use. It is advisable to use a material with a permissible temperature of application of 1525 °C and above as of the solid heat-storing material of the regenerator. Testing of the results of the research was carried out on pilot industrial samples of bath melting furnaces equipped with HiTAC (high-temperature air combustion system).