Saturated steam at 5 bars is heated to 350 C at constant pre

Saturated steam at 5 bars is heated to 350 °C at constant pressure. Calculate the heat requirement for the following cases: a) A continuous steam is flowing at 150 kg/s. [Ans: 63075 kW] b) A closed container has 150 kg.

Solution

Enthalpy h1 @ 5 bar saturated steam = 2750 kJ/kg

Enthalpy h2 @ 5 bar 350 C   = 3170 kJ/kg

a) Heat required   = m * 2880 - m * 2750 = 150 * (3170 - 2750 ) = 63000 kJ/s

b) Heat required in a closed container =   change in internal energy

                                                        = m * ( U2 - U1)   = 150 * (2880 - 2560 )   = 48000 kJ