Due to its high flexibility and its low energy consumption the regenerative end fired furnace is the working horse of the glass industry. Most mass produced glass products such as bottles and containers of all kind, tableware and glass fibre can be produced with a minimum of fossil fuel firing and thus carbon dioxide emission. Its typical melting capacity is 30 – 500 t/d, in some cases up to 700 t/d can be achieved. Limitations in furnace size result from flame length and crown span width, especially of the burner ports.
If sufficiently dimensioned, the regenerators effect heat recovery of the melting end firing and thus ensure an optimal reduction of energy consumption of the glass melting process. Slightly larger regenerators than necessary are an investment for the future, reducing maintenance effort and common energy consumption increase due to ageing. Additionally this allows a furnace enlargement at the next furnace repair with reduced glass-to-glass time and costs, when reusing the basic design and lower part of the regenerator.
By designing the ports and superstructure properly very low emission values in respect of NOx and CO2 can be achieved. Since there is only one alternating flame in glass flow direction, its optimal adjustment is crucial for glass melting process. After furnace startup the first setting is usually done by experienced HORN® personnel for combustion optimisation, ensuring an optimal melting performance from the start.
A weir wall built into the bottom of the melting end, also called barrier, and a deep refining part increase flexibility and glass quality.
The wall supports the convection in the glass bath, which improves melting. Additional electric boosting improves furnace flexibility and is advantageous in case of coloured glass production.
Additional lances or burners at the furnace sidewall can be mounted in order to lower NOx emissions by staged combustion or increase melting capacity by oxyboosting. Most common is the application of a pressurised air lance in order to lower NOx and generally improve melting. This technology is known as ggENOx and can be applied also while furnace operation. It is most suitable to improve furnaces not showing a good performance.