Enhancement of boiler firing by Controlling of the air supply

Abstract

This thesis aims to improve the boiler firing in practical; boiler firing is multivariable process, still controlled by conventional control strategies. Boiler is pressure vessel designed to heat water or produce steam. The efficiency of the boilers is depending of quality of the material in addition of the good firing; the main elements of the boiler fire which are fuel, air and heat. The good firing in the oil firing boilers is depending on good combustion or fuel to air ratio. The bad firing on the boiler cased in many reasons one of these reasons is fuel to air ratio when air is more than or less than the demand. The bad firing due to increasing air supply causes mainly boiler’s vibration, large sound in addition to loss of flame and stop burners and it also leads to Increasing in exhaust gas temperature and environment pollution. The air supply has economical effect hence it causes the optimizing of fuel consumption to enhance firing by added new primary air system which enhances the shape of flame. The primary air supply source is a downstream of main FD fans and configure the logic control of the primary control damper by PID in the existing DCS and sending commands to primary air fans and their convertors and bypass damper also for the existing DCS control system, the secondary air damper of the burner should be opening during burner flame on. From the comparison of the measuring parameters we observe the enhancing happen by indication of the air –fuel ratio increasing value 0.673 than the previse value, indication of decreasing of outlet gas temperature in one to six degree for the previse value, also Oxygen content in out let gas was decrease between the range 0.002 and 0.011 from the previse values and no abnormal sound happen and vibration minimize about 0.213mm/s form the previse value.