Highly Efficient Heating Systems
If a control system acts as the "brain" of a modern industrial furnace, controlling all the furnace functions as instructed by the operator, the heating system of this furnace plays the role of the “heart”, deserving therefore extraordinary attention.
E-therm TZ provides its furnaces with highly efficient systems of burners at such a technological level that the fuel consumption is low, thus meeting contemporary environmental requirements. Depending on the type, size, and heat capacity of the furnace, operating temperature, modes of operation and equipment utilization in time and also in respect of the local conditions, customer’s imagination and habits, combustion systems are designed that – to a varying extent – make use of the thermal capacity of the fumes exhausted from the furnace working area.
Operating on cold combustion air, burners are used in lower-capacity furnaces and furnaces designed for lower temperatures or those that are used in short cycles only, i.e. where the returns on increased costs for installation of waste heat utilization equipment cannot be guaranteed.
Several of the following variants that make use of waste heat are available for furnaces operated at higher temperatures (ca 800°C to 1,300°C) and mainly then in case of intensively used equipment, mainly furnaces in large forges and rolling mills (listed in the order of fuel savings levels):
- central recuperator with combustion air preheating within the range from ca 350 – 500°C
- recuperative burners with air preheating typically to ca 50% of the exhaust fumes temperature, in °C (i.e. ca 500°C given the fume temperature = 1000°C)
- regenerative heating systems with combustion air preheating up to around 85% of the furnace exhaust fume temperature.
Mainly the last-listed regenerative burners promising the highest levels of fuel savings should preferably be selected to heat up ingots, forged blanks and semi-finished products in car bottom and chamber furnaces to temperature 1200 to 1300°C. Where justified in the case of continuous push-type, walking beam, and rotary hearth furnaces used to heat up materials in rolling mills, regenerative burners are not only suitable means for reducing fuel consumption, but their application will also allow increased capacity of the furnace without any changes in its dimensions. This is mainly significant in reconstructions of furnaces of the above types where it is mostly impossible to change their dimensions because of the necessity to retain the links to the existing loading equipment on the input side and conveyors to rolling mill at the output.