Over heating the Furnace Oil Day tank can create a hazardous condition in the boiler house. Thus the temperature of this tank should be regulated.
All boilers that run on Furnace Oil (FO) have a day oil tank that is placed inside the boiler house. The oil in this tank is kept heated via a steam coil. This heating is done to ensure the viscosity of the oil is sufficient to allow it to be pumped to the burner.
The temperature in the day oil tank is usually set manually, with the steam valve being throttled to a position which the operator identifies by experience. However this practice often leads to temperatures in excess of 70degC in the day oil tank.
The flash point for Furnace Oil is above 66DegC. So storing Furnace Oil at a temperature higher than it's flash point is hazardous. Hence care must be taken to ensure that the temperature in the day oil tank is adequately regulated to ensure safe conditions. In addition to safety, controlling the temperatures overshoot will also reduce the radiation losses and thus the steam consumption.