9.2 Boiler Heat Balance

BOILER HEAT BALANCE

The First law of Thermodynamic state that energy can neither be created nor destroyed. Energy can only be transferred or changed from one form to another. It is also known as Law of Conservation of Energy.

 Boiler heat balance refers to the distribution and accounting of heat in a boiler system. It involves analyzing the energy inputs and outputs to determine the efficiency and performance of the boiler. The heat balance helps in understanding how effectively the fuel energy is being converted into useful heat and whether there are any energy losses or inefficiencies within the system.

 The heat balance equation for a boiler can be represented as follows:

 Energy Input = Energy Output + Energy Losses

 Energy Input:

 Fuel energy: The heat energy generated by burning the fuel in the boiler. It is typically measured in terms of fuel heating value.

 Energy Output:

 Steam energy: The heat energy transferred to the steam produced by the boiler.

Flue gas energy: The heat energy carried away by the flue gases leaving the boiler.

Blowdown energy: The heat energy lost with the blowdown water discharged from the boiler.

Energy Losses:

 Radiation losses: Heat energy lost through radiation from the boiler surfaces.

Convection losses: Heat energy lost through the hot flue gases leaving the boiler.

Unburned fuel losses: Heat energy lost due to incomplete combustion of fuel.

Moisture losses: Heat energy lost with the moisture content in the fuel and combustion air.

Other losses: Heat energy lost through various other sources such as unutilized heat in the ash, leakage, etc.

To perform a boiler heat balance, various parameters and measurements are considered, including fuel consumption, steam flow rate, flue gas temperature, ambient temperature, boiler surface area, and heat transfer coefficients. These parameters help calculate the energy inputs, outputs, and losses to determine the overall heat balance and efficiency of the boiler.

A thorough heat balance analysis enables identifying areas of energy loss and inefficiencies in the boiler system, which can then be addressed through optimization measures, maintenance, and operational improvements to enhance the overall efficiency and performance of the boiler.

 In Power Station:

Chemical Energy (Fuel)
👇
Boiler	👉	Losses
👇
Heat Energy
👇
Steam
👇
Kinetic Energy
👇
Turbine	👉	Losses
👇
Mechanical Energy
👇
Generator	👉	Losses
👇
Electrical Energy

  In Boiler:

 

	HEAT INPUT	=	HEAT OUTPUT
H1	Heat input of fuel	H3	Heat consumed in generating steam
H2	Heat input of Air	H4	Heat loss in flue gasses
		H5	Heat loss due to moisture is formed due to combustion of hydrogen present in fuel
		H6	Heat loss due to moisture in fuel
		H7	Heat loss due to incomplete combustion of C to CO
		H8	Heat loss due to un burnt carbon
		H9	Heat loss due to blow down
		H10	Unaccountable heat loss