Energy saving by controlling the inlet air flow of a oil fired boiler using a VSD driven blower fan - Case study

The global energy crisispsilas has increased the electricity tariff. Recent top up tariff in Sri Lanka has forced the industries to optimize the energy usage in all aspects. In dipped product industry, a larger portion of energy is consumed by the steam and hot water boilers. Further, electrical motors in the boiler play a major role in consuming the electricity. The mostly used energy saving techniques in the boiler is controlling the airflow using a valve. It is known that the technique saves some energy, however, it is not the best available technique. . In this paper, a 10 MW industrial fuel-air mixing hot water boiler is studied. The measured data has proven that the conventional energy saving technique is not efficient. From the studies it has been proven that putting up a VSD at the blower fan is the most efficient method for energy saving. With the help of characteristic graphs of the motors, it is illustrated that the control technique based on the plant demand supplied off a VSD is much effective. The calculated and measured results have shown that a large energy savings is obtainable at lower load operations and hence validate the effectiveness of the proposed control method.