Boiler Calculator watch tutorial view guide

Determines the amount of fuel energy required to produce steam with specified properties at a given flow rate using general boiler operational characteristics.

Calculation Details

Step 1: Determine Properties of Steam Produced

Using the Steam Property Calculator, properties are determined using Steam Pressure and the selected second parameter (Temperature, Specific Enthalpy, Specific Entropy, or Quality). The Specific Enthalpy is then multiplied by the Mass Flow to get the Energy Flow:

• Steam Energy Flow = Specific Enthalpy * Mass Flow

Step 2: Determine Feedwater Properties and Mass Flow

The feedwater flow rate can be calculated from steam mass flow and blowdown rate:

1. Blowdown Mass Flow = Feedwater Mass Flow * Blowdown Rate
2. Steam Mass Flow = Feedwater Mass Flow - Blowdown Mass Flow
3. Steam Mass Flow = Feedwater Mass Flow - Feedwater Mass Flow * Blowdown Rate
4. Feedwater Mass Flow = Steam Mass Flow / [ 1 - Blowdown Rate ]

Using the Steam Property Calculator, properties are determined using Deaerator Pressure and Quality = 0 (Saturated Liquid). The Specific Enthalpy is then multiplied by the Mass Flow to get the Energy Flow:

• Feedwater Energy Flow = Specific Enthalpy * Mass Flow

Step 3: Determine Blowdown Properties and Mass Flow

Using the calculated feedwater mass flow and blowdown rate:

• Blowdown Mass Flow = Feedwater Mass Flow * Blowdown Rate

Using the Steam Property Calculator, properties are determined using Steam Pressure and Quality = 0 (Saturated Liquid). The Specific Enthalpy is then multiplied by the Mass Flow to get the Energy Flow:

• Blowdown Energy Flow = Specific Enthalpy * Mass Flow

Step 4: Determine Boiler Energy

• Boiler Energy = Steam Energy Flow + Blowdown Energy Flow - Feedwater Energy Flow

Step 5: Determine Fuel Energy

• Fuel Energy = Boiler Energy / Combustion Efficiency

Assumptions

• Deaerator provides feedwater near the boiling temperature for the deaerator's set operating pressure. (Saturated Liquid)
• Steam, Boiler, and Blowdown Pressure are the same.
• Combustion Efficiency is the % of fuel energy that is directly added to the feedwater and not otherwise lost or used.
• Blowdown Rate is the % of incoming feedwater mass flow rate that leaves the boiler as a saturated liquid at boiler pressure.
• Does not include any evaluation of any complex boiler configurations or fluctuations in operation.
• Energy from motors (pumps, fans, etc.) are not considered.
• Boiler and fuel types are not considered.