Check Atom Balance ¬

This node is only shown when project data is provided in moles. When Mass Density is selected as units of concentrations in the Units Configuration node, the Check Atom Balance node is hidden.

This feature allows you to check the atom balance in the reaction stoichiometry and experimental data. In order to get a reliable report, the atomic formulae must be correctly loaded for the compounds in the Formula node.
Two checks are provided in this node. The first check is for the stoichiometry of the Reactions in the project.
In Mode Estimation, an additional report on atom balance error in the experimental data is provided. Atom Balance error is calculated with respect to the first datapoint. This report is provided for all reactors, except for CSTR's with Intermediate Feed and/or Intermediate Separation enabled.
A guided explanation about how to use this feature can be found in the Check Atom Balance Example.

Reaction Balance

This grid reports any inconsistency in the Atom Balance for the reactions, as long as the atom count for the compounds was entered in the Formula node,
For the reactions where atom counts are not the same in the left and right hand sides, the sum of the atoms on the Right Hand Side (RHS) and on Left Hand Side (LHS) of the reaction are reported.

Actions

In this grid, you may set options for the calculation of Atom Balance data and errors:

• Hide Intermediate DataPoints Checkbox: By selecting this checkbox, atom balance information will be provided for only the first and last datapoint of each set.
  This is useful for PFR reactors, where the interpolation of a profile such as temperature along the reactor requires several datapoints. As experimental compositions are known only at the first and last datapoints (entry and outlet of the reactor), selecting this option avoids the display of incorrect error values for the intermediate datapoints.
  
• Element combo: Here, you may select the element whose balance data and errors are to be displayed.
  
• | Error| >= value: Information is displayed only for datapoints having absolute percentage error higher that the value specified here.
  The default value is 5%, meaning that datapoints having error between -5% and +5% will be ignored in the report.
  

Atom Balance Report

In this view, atom balance values and errors are reported for the Sets and Datapoints, in accordance with the options selected in Actions grid. A chart for the atom error is also shown.

The table with the numerical information is organized in columns as explained below:

• Set Name and Datapoint columns: These columns identify the experimental datapoint.
  
• Element Name - Error (%) column: It shows the percentage error for the element.
  The reported error for a given datapoint is with respect to the first datapoint of the same set. Positive values indicate that the Element experimental content at a given datapoint is higher than the element content at the First Datapoint. If there are inflows, then the error is with respect to the first datapoint plus all inflows.
  
• Element Name - Total Moles column: Here, the total amount of the element in the datapoint of the set is reported.
  The value is obtained from the Total Moles series of the experimental data, as shown in the formula below. Here, E_c is the element content of each compound and TM_Set,Pt,c is the Total moles of each compound c at each set(set) and datapoint(pt).
  
  Element-Total Moles _{Set, Pt} = Sum_c ( TM_Set,Pt,c * E_c )
  
  
• Element Name - Integrated Flow column: This column is only shown for Batch reactors with one or more Inlet/Outlet flows.
  It calculates the net accumulation/loss of the selected Element due to Inflows and Outflows. The integration is based on the composition and rate of the flows.
  

You may sort the rows by a clicking the column header.

In the chart, the Y axis shows the percentage error for the selected element.
When you point to a bar in the chart, a tooltip shows the correponding Set name and Datapoint (DP).

Example: Check Atom Balance

Project Explorer

Formula

Reactions