The function of Economizer in Boilers is to heat Boiler filler water by utilizing heat from combustion gas in the Boiler. With increasing temperature of Boiler filler water, Boiler Efficiency will also increase.
The remaining fuel combustion gas in the boiler still has a high enough temperature. By passing the combustion gas through the Economizer pipes, there will be heat transfer that will be absorbed by the Economizer pipes and the heat is passed into the Boiler filler water contained in the Economizer pipes.
Economizer’s function on Boiler Efficiency
As the temperature exits the Economizer, the water temperature in the drum boiler will also be high. If the water in the drum boiler is already high, less heat will be needed to convert the water to steam according to the planned amount. Less calorie needs will certainly have an impact with reduced fuel use. With Increasing Efficiency in a Boiler, it will make the company’s expenses will also be more economical in terms of reducing the purchase of Boiler fuel.
Location of Economizer
Economizer is one of the important components of the boiler which is located inside the boiler, precisely between the Superheater and the Air Heater. The Economizer in Boilers usually consists of several levels, and between Economiser one level and another is separated by a room that contains a Soot Blower to clean Economizer pipes from dirt or dust that sticks to the outer Econpmizer pipes.
To connect Economiser level one with another level, Economiser is usually connected by a Header that functions as a water collector and also to facilitate maintenance of Economiser by maintenance if there is damage to the Economizer pipes. Some Manholes are also found in the Boiler wall between the one and the other Economizer which functions as a human inlet to check the condition of the Economizer pipes during shutdown boilers.
Water flow to the Economizer
Boiler filler water flow comes from BFP (Boiler Feed Pump) and passes the Economizer before heading to Drum Boiler / Steam Drum Boiler. In the Economizer the temperature of the Boiler filler water at the outlet / outlet side of the Economizer will be higher than the temperature of the inlet water at the Economiser inlet. This happens because the temperature between Boiler filler water contained in the pipes of the Economist is lower than the temperature of the exhaust gas Boiler that is on the outside of the Economizer pipes, so that heat transfer will occur from the combustion gas to the Boiler filler water. The exhaust gas temperature will drop after passing the Economizer and vice versa The water temperature of the Boiler Drum filler will increase after passing the Economizer.
The water temperature that enters the Economizer depends on the water temperature of the Tank Deaerator and HPH (High Pressure Heater). If the temperature of Boiler filler water from a high Deaerator and HPH is also operated, the temperature of the water entering the Economizer will also be high. Usually when the load of the High Turbine Generator and Steam Extraction Turbine is abundant then the temperature of the HPE Deaerator and Outlet will also be high and of course the temperature of the Boiler filler water entering the Economiser will also be high.
Alian Exhaust Gas at Economizer
Boiler combustion gases will pass the Economizer on the outside of the Economizer pipe. Burning in the boiler besides producing heat will also produce exhaust gas that will be disposed of into the atmosphere. The flow of exhaust gas in the combustion chamber will pass through the Boiler Components such as Superheater, Economizer, Air Heater, ESP, FGD, New Chimney to the Atmosphere.
The residual combustion gas from the boiler will pass through the superhaeater and forwarded to the new Economizer outlet to the Inlet Economizer before heading to the Air Heater.