the component material balance for the distillation tower is not balance
for flowrate of 408 kg/hr of 25 % furfural and 75% water
the bottom flowrate should be 100 kg/hr of 96% furfural
and distillate should be 308 kg/hr of 98% water
but from simulation the flowrate of distillate and botom are not same with the material balance of furfural having a difference in input and output
i.e input not equal to output of furfural
The problem statement that you have provided doesn't match with the inputs given in the simulation file. As you mentioned that the inlet composition is 25% furfural and 75% water, it is not clear if they are mass % or mole %. However, in the simulation file, you have used the input of 50% furfural and 50% water on the basis of mole.
With the given input values in the simulation file, the material balance is absolutely accurate.