1000 kg/h of a fruit juice with 10% solids is freeze-concentrated to 40% solids

 Problem No 3: 

1000 kg/h of a fruit juice with 10% solids is freeze-concentrated to 40% solids. The dilute juice is fed to a freezer where the ice crystals are formed and then the slush is separated in a centrifugal separator into ice crystals and concentrated juice. An amount of 500 kg/h of liquid is recycled from the separator to the freezer. Calculate the amount of ice that is removed in the separator and the amount of concentrated juice produced. Assume steady state.

Solution:

Step 2:

Write the total and component mass balances in the envelope around the process:

i) Overall mass balance:

1000 = I + J (1)

ii) Soluble solids mass balance:

0.10 * 1000 = 0.40 * J

                        ⇰ 100 = 0.40 * J

                        ⇰ J = 100/0.40

                        ⇰ J = 250                                        (2)

From equation (1), 

                        

                           1000 = I + 250

                            

                           I =  750

From equation (2), find J=250 kg/h and then from equation (1) find I=750 kg/h. (Solved)