Economy in natural gas together with an increase in the quality of fired parts are basic problems in the production of refractories.A large quantity of natural gas is consumed in the refractory industry in kilns.The use of most progressive types of thermal equipment for firing parts and optimization of the firing system will lead both to significant economy in natural gas and to acceleration of the firing processes.In recent years there has been an increase in the production of high-quality oxide refractories, which makes improvement in the method of their production, in particular the method of firing important.For firing these parts, more and more use is being made of batch furnaces, in the working space of which it is possible to obtain the required high temperatures.However, significant disadvantages, the primary of which is the large fuel requirement per unit of production, are inherent in firing in batch furnaces.For example, at Magnesite Combine 1250 kg of standard fuel is consumed in batch furnaces for firing one ton of magnesite inserts for the plates of slide valves.Firing of such parts in continuous furnaces requires several times less fuel.The use of continuous kilns is restrained by the fact that in them it is not possible to obtain temperatures of 1750-1850~ and to maintain the required firing cycle.Recently small tunnel kilns with an ejector system of firing [1][2][3], which are promising both from the point of view of obtaining high firing temperatures and in respect to flexibility in regulation of the thermal cycle, have been used.These furnaces are capable of replacing batch furnaces.It should be noted that kilns with an ejector system of firing require further improvement and optimization of the thermal cycle.In Snigirevka Division of Vnukovo Refractory Part Plant corundum parts are fired in small kilns with an ejector system of firing.The length of the kilns is 15 and 17 m. The temperature in them did not exceed 1650-1680~ Attempts to increase the temperature for the purpose of higher quality firing did not provide positive results.In the construction of a new high-temperature tunnel kiln the disadvantages of the thermal operation of existing small kilns were taken into consideration.Individual portions of the equipment were modernized, which made it possible to substantially improve the technical and economic indices of the kiln.For example, the use of the controllable gas burners developed in the All-Union Scientific-Research Institute for the Utilization of Gas made it possible to more flexibly control the thermal operation of the kiln. The installation, in addition to the lower burners, of an upper row of burners led to more uniform heating of the parts through the height of the charge.The thermal losses to the atmosphere in the high-temperature portion of the kiln were decreased by additional insulation of the roof.The height of the sand seals was increased, as the result of which gas exchange of the working area of the furnace with the atmosphere was decreased. The length of the kiln is ...
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