Boiler efficiency and fuel consumption

[CR1310]

Homework Statement

A boiler is to produce 6250 kg/h of steam superheated by 40 oC at a pressure of 2.1 MN/m2. The temperature of the feedwater is 50 oC. If the thermal efficiency of the boiler is 70%, how much fuel oil will be consumed in one hour? The calorific value of the fuel oil used is 45000 kJ/kg, cp of superheated steam is 2.093 kJ/kg K.

for pressure 2.1 Mn/m2
Hfg = 1880 kJ/kg
Hf = 920 kj/KG
sat temp - 214.9

Homework Equations

I want to know how to calculate the enthalpy of the feed water to put back into the boiler efficiency question.
why am i given cp?

The Attempt at a Solution

using the formula : boiler efficiency = m x (H2-H1) / fuel consumption x calorific value

H1 is the feed water enthalpy and i am told not to use thermodynamic tables

I got some help from a university lecturer and solved it.

 

[0drt9]

how did you solve this?

 

[SteamKing]

how did you solve this?

The OP posted this problem 3 and a half years ago and never was seen again. I don't think you're going to get a response.