Question

The figure shows a flowchart for the production of potassium nitrate. The fresh feed consists of 850 kg per hour of a 20% potassium nitrate solution which is concentrated in an evaporator. Before entering the evaporator the fresh feed is mixed with a regulated stream of a saturated solution at 40 degrees Celsius from a filter. The saturated solution of this salt at 40 degrees Celsius has a composition of 0.6 kg of salt per kilo of water. From the evaporator two streams come out pure water (upstream of 3) and the solution concentrated downstream (stream 4). The current 3 consists 50% of the water fed to the evaporator. The concentrated solution is cooled and saturated in the crystallizer up to 40 degrees Celsius which causes precipitation of crystals then filtered. The liquid (filtrate that passes through the filter) is a saturated solution 0.6 kg of salt per kilogram of water and it is re-circulated. Wet solids retained in the filter contains 92 % of pure salt crystals and retains in their interstices 8% of the saturated solution.

expresses the composition of the saturated solution of potassium nitrate at 40% In mass percentage subsection

  calculates the mass percentage of potassium nitrate and the current 7

Do an analysis of degrees of freedom (overall) and verify that the problem has enough information to calculate the mass flows of the currents 3 and 7. Determine the flows 3 and 7 in kilograms per hour.

Do an analysis of freedom in the filter and determine enough information to calculate the current recirculation mass flow 6. if there are calculations in kilograms per hour

Determine currents 2, 4 and 5.

Answer 1