PECM Issue 31 2018 | Page 127

T o light F uel gas main burner T o operate draft gauge The fuel gas main burner is only a big pilot. Follow the same procedure to light it. The only difference is that you do not need a separate light since the pilot burner is just there to serve you. However, there are secondary air registers to regulate the oxygen air requirement for burner and pip-hole to view the flame status. 1. Adjust the draft gauge to give you the pressures you need across the heater by regulating the reading on the indicator. The gauge scale graduated in millimeters (mm) or water. T o light fuel oil main burner Understanding the fuel gas burner is not enough to light a fuel oil burner because there are a lot of differences. Features like atomizing steam two inlets to burner ( one for steam and the other for oil) etc that we need to be familiar with. Drain all condensate from the steam lines first 1. Crack open the atomizing steam to the burner nozzle to purge nozzle tip. 2. Crack open the fuel oil valve to commission the oil flow to burner nozzle making sure that the steam flow is slightly more than the oil flow. With the pilot already lit the oil will immediate ignite. 3. Let the fuel oil pressure differential be within the set limit. Maintain fuel oil circulation at all time. 4. Throttle the two valve together until the required flame achieved. 5. Adjust the secondary air register to regulate the flame color. 2. Keep the pressure of the heater radiation section on the slight positive side say 2-5mm of water. 3. Keep the pressure of heater convection section on the slight negative side, say 2-5mm of water. 4. Above convection section should be more negative while the below convection section a little above zero. Just note that the pressure should be such that a little vacuum surge or pressure differential is created to provide the driving force necessary for effective pressure control. T o set stack damper The stack damper is like the chimney of the kitchen where flue gas escapes to the atmosphere. So be careful not to loose off the heat you generated before using it. For efficient heater performance keep the damper at 60% opening. 1. Adjust the damper opening by hand turning the handle across the scale of the damper. The scale is mostly graduated in percentage of the damper opening. 2. Keep the setting initially at 30% and gradually raise it to 60%. This is mostly applicable to atmospheric heaters. T o soot blow heater tubes Soot blowing is the removal of carbon deposits and ash on the surface of heater tubes and on the flue gas passages which result from fuel combustion. Heater soot-blow could be carried out manually or automatically depending on the provision. Heater tubes are blown with steam. Let us look at the basic requirement needed to soot-blow heater tubes from deposits of carbon that results from fuel combustion. 1. Check and drain any condensate from the steam line. 2. Hand turn the blower shaft to free it from stiffness. 3. Inform the panel man/ chief operator your readiness to begin soot- blowing. 4. Open the damper a little above normal to allow quick relief of soot through the stack. 5. Develop your sequence steps if blower is on manual mode. 6. Advance the soot blower following the sequence developed one after the other. 7. Isolate the steam and return the damper setting to the position after the soot-blowing operation.