How to Calculate and Solve for Enthalpy of Superheated Steam | Enthalpy

The image above represents enthalpy of superheated steam. To calculate enthalpy of superheated steam, five essential parameters are needed and these parameters are Constant Pressure (C_ps), Enthalpy of Water (h_f), Enthalpy of Vapourization (h_fg), Superheated Temprature (T_sup) and Saturated Temprature (T_s).

The formula for calculating enthalpy of superheated steam:

h_sup = h_f + h_fg + C_ps(T_sup – T_s)

Where:

h_sup = Enthalpy of Superheated Steam
C_ps = Constant Pressure
h_f = Enthalpy of Water
h_fg = Enthalpy of Vapourization
T_sup = Superheated Temprature
T_s = Saturated Temprature

Let’s solve an example;
Given that the constant pressure is 2, the enthalpy of water is 4, the enthalpy of vapourization is 6, the superheated temperature is 8 and the saturated temperatue is 10. Find the enthalpy of superheated steam?

This implies that;

C_ps = Constant Pressure = 2
h_f = Enthalpy of Water = 4
h_fg = Enthalpy of Vapourization = 6
T_sup = Superheated Temprature = 8
T_s = Saturated Temprature = 10

h_sup = h_f + h_fg + C_ps(T_sup – T_s)
h_sup = 4 + 6 + 2 x (8 – 10)
That is, h_sup = 10 + 2 x (-2)
h_sup = 10 + (-4)
h_sup = 6

Therefore, the enthalpy of superheated steam is 6 J/Kg.

Read more: How to Calculate and Solve for Enthalpy of Wet Stream | Enthalpy

Calculating the Constant Pressure when the Enthalpy of Superheated Steam, the Enthalpy of Water, the Enthalpy of Vapourization, the Superheated Temperature and the Saturated Temperature are Given

C_ps = ^{h_sup – h_f – h_fg} / _{Tsup + Ts}

Where:

C_ps = Constant Pressure
h_sup = Enthalpy of Superheated Steam
h_f = Enthalpy of Water
And then, h_fg = Enthalpy of Vapourization
T_sup = Superheated Temprature
T_s = Saturated Temprature

Let’s solve an example;
Find the Constant Pressure when the enthalpy of superheated steam is 30, the enthalpy of water is 10, the enthalpy of vapourization is 4, the superheated temperature is 8 and the saturated temperature is 2.

This implies that;

h_sup = Enthalpy of Superheated Steam = 30
h_f = Enthalpy of Water = 10
And then, h_fg = Enthalpy of Vapourization = 4
T_sup = Superheated Temprature = 8
T_s = Saturated Temprature = 2

C_ps = ^{h_sup – h_f – h_fg} / _{Tsup + Ts}
C_ps = ^{30 – 10 – 4} / _{8 + 2}
So, C_ps = ¹⁶ / ₁₀
C_ps = 1.6

Therefore, the constant pressure is 1.6.

Read more: How to Calculate and Solve for Enthalpy at Constant Pressure Heating or Cooling | Enthalpy

Calculating the Enthalpy of Water when the Enthalpy of Superheated Steam, the Constant Pressure, the Enthalpy of Vapourization, the Superheated Temperature and the Saturated Temperature are Given

h_f = h_sup – h_fg – C_ps(T_sup – T_s)

Where:

h_f = Enthalpy of Water
h_sup = Enthalpy of Superheated Steam
C_ps = Constant Pressure
h_fg = Enthalpy of Vapourization
T_sup = Superheated Temprature
T_s = Saturated Temprature

Let’s solve an example;
Find the enthalpy of water when the enthalpy of superheated steam is 42, the constant pressure is 18, the enthalpy of vapourization is 12, the superheated temperature is 10 and the saturated temperature is 4.

This implies that;

h_sup = Enthalpy of Superheated Steam = 42
C_ps = Constant Pressure = 18
h_fg = Enthalpy of Vapourization = 12
T_sup = Superheated Temprature = 10
T_s = Saturated Temprature = 4

h_f = h_sup – h_fg – C_ps(T_sup – T_s)
h_f = 42 – 12 – 18(10 – 4)
Then, h_f = 30 – 18(6)
h_f = 30 – 108
h_f = -78

Therefore, the enthalpy of water is -78 J/Kg.

Read more: How to Calculate and Solve for Entropy of Water | Enthalpy

Calculating the Enthalpy of Vapourization when the Enthalpy of Superheated Steam, the Constant Pressure, the Enthalpy of Water, the Superheated Temperature and the Saturated Temperature are Given

h_fg = h_sup – h_f – C_ps(T_sup – T_s)

Where:

h_fg = Enthalpy of Vapourization
h_sup = Enthalpy of Superheated Steam
C_ps = Constant Pressure
h_f = Enthalpy of Water
T_sup = Superheated Temprature
T_s = Saturated Temprature

Let’s solve an example;
Find the enthalpy of vapourization when the enthalpy of superheated steam is 44, the constant pressure is 38, the enthalpy of water is 24, the superheated temperature is 20 and the saturated temperature is 14.

This implies that;

h_sup = Enthalpy of Superheated Steam = 44
C_ps = Constant Pressure = 38
h_f = Enthalpy of Water = 24
T_sup = Superheated Temprature = 20
T_s = Saturated Temprature = 14

h_fg = h_sup – h_f – C_ps(T_sup – T_s)
h_fg = 44 – 24 – 38(20 – 14)
So, h_fg = 20 – 38(6)
h_fg = 20 – 228
h_fg = – 208

Therefore, the enthalpy of vapourization is – 208 J/Kg.

How to Calculate Enthalpy of Superheated Steam Using Nickzom Calculator

Nickzom Calculator – The Calculator Encyclopedia is capable of calculating the enthalpy of superheated steam.

Now, Click on Chemical Reaction Thermodynamics under Materials and Metallurgical

So, Click on Enthalpy under Chemical Reaction Thermodynamics

Now, Click on Enthalpy of Superheated Steam under Enthalpy

The screenshot below displays the page or activity to enter your values, to get the answer for the enthalpy of superheated steam according to the respective parameter which is the Constant Pressure (C_ps), Enthalpy of Water (h_f), Enthalpy of Vapourization (h_fg), Superheated Temprature (T_sup) and Saturated Temprature (T_s).

Now, enter the values appropriately and accordingly for the parameters as required by the Constant Pressure (C_ps) is 2, Enthalpy of Water (h_f) is 4, Enthalpy of Vapourization (h_fg) is 6, Superheated Temprature (T_sup) is 8 and Saturated Temprature (T_s) is 10.

Finally, Click on Calculate

As you can see from the screenshot above, Nickzom Calculator– The Calculator Encyclopedia solves for the enthalpy of superheated steam and presents the formula, workings and steps too.