Task 2 (evaporation)

The evaporation apparatus receives 10.8 t / h of an aqueous 8% solution at a temperature of 74 C. The solution is evaporated to 42.5% mass by non-volatile solute. The pressure in the middle layer of the boiling solution is 0.40 bar. The heating steam pressure is 3.5 bar. The coefficient of heat transfer from the heating steam to the boiling solution is 950 J/(s * m2•K). The loss of the useful temperature difference due to the hydrostatic effect (hydrostatic temperature depression) is Δt g. stat. = 6.1 s. The loss of heat from the heating steam to the environment is 3.5% of the useful heat Qpol = Qnagr + Qisp transferred to the solution. Determine the heat transfer surface of the heating chamber. Calculate the pressure in the barometric condenser, if the value of the hydraulic depression on the path of the secondary steam from the evaporator to the barometric condenser Δt Hydraulic = 1.2 S.