There are many important parameters to be monitored during any Power plant normal & emergency operations. Furnace pressure is one such very important parameter, which needs continuous control, protection & monitoring against any furnace explosion and implosion. The National Fire Protection Association (NFPA) codes, such as NFPA 85: Boiler and Combustion Systems Hazards Code are dedicated to fire and furnace explosion and implosion protection. The NFPA also requires some additional logic for the furnace pressure control loop to ensure adequate operating safety margins. There should be high and low furnace pressure logic to block the ID fan from increasing or decreasing speed, as is appropriate. A high furnace pressure signal the fan should be blocked from decreasing speed and on a low furnace pressure signal it should be blocked from increasing speed. A main fuel trip (MFT) there should be MFT kicker logic. An MFT occurs when the burner management system detects a dangerous condition and shuts down the boiler by securing the fuel per NFPA and boiler manufacturer requirements. This paper describe the Furnace explosion , Implosions, Furnace pressure set points, cause and remedies in Coal Based Utility Boiler keeping NFPA-8502 standard into consideration[2,5].

MFT-Master Fuel Trip