Abstract:
During the melting of metals, it is reported that around 50% of the total energy is lost in
flue gases. Therefore there is always a need to improve the efficiency of the furnaces. In the
first phase of the thesis work, the design and development of an energy-efficient oil-fired
tilting furnace with an innovative recuperator are reported. The internal hollow pipe of the
proposed recuperator is so designed that at its exterior cylindrical surface, multiple turns of a
guideway are welded in a spiral fashion. This increases the heat transfer between the flue gas
and ambient air to the burner. The study shows that the efficiency of the oil-fired tilting
furnace got enhanced by 50% after implementing the proposed recuperator. Specific fuel
consumption without the recuperator was 0.166 kg/kWh, which was reduced to 0.138 kg
/kWh with the recuperator. A channel for flue gases is provided in the developed furnace,
which helps to divert hazardous gases away from the working environment. The second phase
of the thesis work presents an experimental study to evaluate the influence of air swirl vane
angles on pollutants in a heavy oil fuel-fired furnace with a recuperator. A novel burner
system with a range of concentric air swirl generators (vane angles of 15°, 20°, 30°, 45°, 60°,
and 90°) was ultimately incorporated to the combustion chamber of the furnace. This study
examined the thermal efficiency and the polluting emission parameters of CO2, HC, CO and
NOx. According to the results, preheated air-fuel and air swirl generators with vane angles of
45° and 30° emit the least HC and CO, whereas air swirl vane angles of 90° emit the most. A
preheated primary air swirl vane angle of 45° results in the lowest NOx emission (25 ppm)
value. Furthermore, larger air swirl vane angles of 45° result in increased temperature,
premixed combustion, and a rise in NOx emission. The results showed that when the
temperature of the preheated primary and secondary air and heavy oil fuel combination
increased, so did the mean effective temperature of the combustion gases.
