In 2018 Inventum Ukraine completed the overhaul of a big pre heating furnace with upgrading. Our company faced with a number of tasks in order to modernize the refractory lining, reduce gas consumption, increase occupational safety and reduce environmental pollution. During detailed engineering, our company specialists paid special attention to reducing gas consumption and improving the energy efficiency of the furnace. To solve these problems, we used materials based on ceramic and polycrystalline fibres. Polycrystalline fibres are innovative refractories that have been used in this kind of furnaces for the first time in Ukraine. These materials have high refractory and thermal stability, as well as excellent thermal and physical properties. For better efficiency, it was very important to take into account the peculiarities of the furnace: sloped roof, overpressure beams, burner embrasures, flue gas convection and other elements. The application of fibrous materials required new technical solutions. Our technical specialists successfully coped with this task, and managed to minimize changes in the furnace design.
Compared with bricks refractories, the ceramic fibre lining is at least ten times lighter and thinner, and the use temperature reaches 1600 °C. Also, ceramic fibre is resistant to temperature drops and its durability lasts longer, even if the furnace is repeatedly extinguished and re-ignited. The temperature decreased from 200-300 °С to 50-60 °С on the furnace body, so that it made it possible to arrange its service.
After switching off the furnace and its cooling, the specialists of the installation department began an upgrading project. At the first stage, we dismantled the outdated brick lining (about 700 tons) and then proceeded to design works due to the project. Since the thermal conductivity of the new material is significantly lower than the old one, the thickness of the lining has decreased. To preserve the working volume of the furnace, special metal constructions of the vaults were assembled with the subsequent installation of a lining of ceramic and polycrystalline fibre on them. To improve refractoriness and preserve the integrity of metal structures, they were coated with silicone paint.
The lining of the furnace was made using combined refractory materials, taking into account the technological features of 5 temperature zones and SIO beams. These materials, made by world leading refractory manufacturers, were supplied from the USA, Belgium, China and France.
Thermal insulation of the outer surface of the air ducts was made of lightweight ceramic-fibre mats.
The burners were adapted to the new lining of the furnace, namely: the configuration was changed and the nozzles were modernized, special inserts were installed and the air outlet was reduced. This technical solution allowed us to burn fuel more efficiently and to reduce the amount of harmful emissions into the atmosphere.
Besides of usage of innovative refractory materials, we have installed Automated control system of production technology (ACSPT) on base of Programmable logic controller SIEMENS with dynamic control of gas-air ratio, burners work and process control is now automatically regulated.
The furnace has been successfully commissioned. All the necessary works and the achievement of the tasks are performed.