Create the constraints

Using the Constraint tool from the Drawing Toolbar, add a methane component constraint with the name CH4_CONSTRAINT and an ethane component constraint with the name C2H6_CONSTRAINT.

The constraint equation for CH4_CONSTRAINT is:

STREAM(FT010;COMPONENT;CH4)/100*STREAM(FT010;RECMASSFLOWRATE)-STREAM(FT011;COMPONENT;CH4)/100*STREAM(FT011;RECMASSFLOWRATE)

The constraint equation for C2H6_CONSTRAINT:

STREAM(FT010;COMPONENT;C2H6)/100*STREAM(FT010;RECMASSFLOWRATE)-STREAM(FT011;COMPONENT;C2H6)/100*STREAM(FT011;RECMASSFLOWRATE)-STREAM(FT013;RECMASSFLOWRATE

After adding two constraints in the flowsheet, observe the raw imbalance and reconciled imbalance of the constraint.

You will notice that the reconciled imbalance of the constraint is not zero before you run reconciliation. The values shown are those mathematically derived from the values in the previous reconciliation of this period.