Energy balance

The inclusion of Energy within a stream, process, or node serves the purpose of achieving an Energy balance or Enthalpy balance for the model. This principle is rooted in the concept of energy conservation across the entire system.

Specific enthalpy calculation

The Thermodynamic Equation of State is employed to compute the specific enthalpy for selected components. This specific enthalpy value for each stream is then utilized in subsequent energy balance calculations.

Heat of reaction

Within a process, the heat of the reaction can either be exothermic (releasing heat) or endothermic (absorbing heat). This directly impacts the enthalpy of the system.

By analyzing this heat exchange, we can determine whether heat is being absorbed or released from the system.

Assumption of No Heat Loss: The enthalpy balance is calculated under the assumption that there is no heat loss within the system.

In summary, understanding the energy flow and enthalpy changes allows us to maintain a balanced energy state within the model.

Enthalpy is calculated based on,

1. Thermodynamic equation of state.

2. Based on the component specific enthalpy

3. Heat of reaction as the manual value

4. Steam, Air, Flue gas enthalpy is calculated by APA.

Calculate the specific enthalpy of the stream

5. Perform steps 1 to 1d as listed in Emission monitoring and reporting.

   Note: AVEVA Production Accounting has in built 121 components library and carbon fraction, Enthalpy and Molecular weight is pre-defined for them, and user can change the value at any time.

6. To Add the component to the stream,click the Stream -> Design property and then right click Component name and select New.

   

7. Add the selected thermo component to the component and add the tag name from the available tags and its default value.

   

Import the tag

8. Click File -> Get Tag Data From DB.Select and right click a tag and then click Import.

   

   The Component is added to the stream. Once the model is reconciled, then the component list of the stream will be viewed in the component list

Calculate the specific enthalpy method

9. Click the Stream -> Design operation ->Energy Data tab.

10. Choose the Enthalpy Calculating Method as component-from the dropdown menu. This method calculates the specific enthalpy based on the selected component.

11. Considering the operating temperature and pressure, the specific enthalpy is determined in terms of kJ/kg. This value reflects the energy content per unit mass for the chosen component.

12. Finally, the overall enthalpy is calculated by AVEVA Production Accounting using the Measured, Reconciled Mass Data for all relevant events from the specific Enthalpy Data.