OME 3343 Thermodynamics          Dr. A. Abtahi

Tomato Juice

Tomatoes and tomato juice are easily damaged by high temperature. Concentration of tomato juice is accomp­lished using modest heating (by hot water in a heat exchanger) followed by mechanical extraction of water by action of a vane pump. The vane pump maintains a low pressure over the juice and ejects water as vapor from the separator.

The concentration process has two flow streams. Hot water (1) enters, cools as it passes the juice (in counterflow) then exits (2). The other stream, juice, enters, (3) is warmed then enters the separator where its stream divides into concentrate exiting as liquid (4) and vapor exhausted by the vane pump (5). Use the information of the drawing.

(i) Calculate the mass rate of water that exits the vane pump as water vapor (5).

(ii) Calculate the mass rate of Hot Water for this system.

(iii) Calculate the least horsepower of the vane pump.