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STEAM TABLE Nur Istianah,ST.,MT.,M.Eng

THP UB 2017

STEAM

• Water in gas phase

• Contain higher energy (heat)

• Has wide uses in food industry:

Preheating

Boiling

Sterilisation

Pasutisation

Cleaning

etc

Energy

Sources

Coal, oil, gas

Nuclear

Combustion (Boiler)

HEAT

Potential Energy

Mechanical energy (Turbin)

Electricity (Generator)

Light Calor

(Termal) Rotor

(mechanic) Saved energy

(Transformator)

Fire Tube boiler

Water Tube boiler

STEAM TABLE

• The steam tables are tabulated values for the properties of saturated and superheated steam.

• Specific volume is the volume in cubic feet occupied by 1 lb of water or steam under the conditions given.

• Enthalpy is the heat content of a unit mass of steam or water at the indicated temperature and pressure.

Boiling point

Boiling point

Saturated Vs Superheated steam

Sat. Liquid

Sat. Vapor

Super heated

Saturated steam

Superheated steam

STEAM TABLE

Example: At what vacuum would water boil at 80◦F?

Answer: 0.50683 psia

HEAT

• Heat is a kind of energy that is related to the temperature or phase change. It involved in thermodynamic transformations

• Sensible heat is defined as the energy transferred between two bodies at different temperatures

• Latent heat is the energy associated withphase transitions

ENDOTERM

System Energy

(steam)

Environment

Q>0

Steam in endothermic process

Steam (sat.vapor)

Steam (sat.liquid)

Susu (30°C)

Susu (60°C)

Sensible heat: mCp(T2-T1)

Latent heat: mhfg

Ilustasi pasterisasi susu dengan HE

Sensibel and latent heat

∆H = H2 – H1 = Q = m 𝐶𝑝𝑑𝑇 = 𝑚𝐶𝑝

𝑇2− 𝑇1 = 𝑄𝑇2

𝑇1

Q= mhf atau Q = mhv

Energy Balance

Total energy entering the system

Total energy leaving the system

Change in the total energy of system =

The first law of thermodynamic states that energy can be neither created nor destroyed.

Conservation Law

E in = Eout + Acc

For steady state process:

E in = Eout

Steam in energy balance

Q= 𝑚𝐶𝑝 𝑇2− 𝑇1 = ms(hg – hf)

For T2 > T1

Laten heat

Laten heat

-40

-20

0

20

40

60

80

100

120

140

Tem

pe

ratu

r

Entalpi

Heat of Fusion (+)

Heat of Vaporization (+)

Heat of Solidification (-)

Heat of Condensation (-)

Heat term

• Units of heat: joule (J), Calorie (Cal), or British thermal unit (Btu)

• 1 Calorie: amount of heat needed to raise the temperature of 1 gram of water by 1 C0 (from 14.50C to 15.50C)

• 1 Btu: amount of heat needed to raise the temperature of 1 lb of water by 1 F0 (from 630F to 640F)

• 1 cal = 10-3 kcal = 3.969 x 10-3 Btu = 4.186 J

Example

– 150 kg of apple was heated at 30oC until the temperature raise up to 50oC. Calculate the heat transfered if the apple has composistion; water 84,4%, Protein 0,2%, carbohydrate 14,5%, fat 0,6%, dan Ash 0,3% ?

– How much steam (saturated at 105oC) need for that process ?

– Defined: m = 150 kg

T1 = 0oC

T2 = 20oC

Xw = 0,844, Xp = 0,002,

Xh = 0,145, Xf = 0,006, Xa = 0,003

– Q = ?

– Solusi: ∆H = Q = m CpdT𝑇2

𝑇1

• For unknown Cp, Cp can be calculated from Siebel Eq.

•

• ∆H = Q = m CpdT𝑇2

𝑇1

= 150 kg x 3,76 kJ/kg.oC x (20-0) oC

= 11280 kJ

Cp = 1,424Xh +1,549Xp + 1,675Xf + 0,837Xa + 4,187Xw = 1,424 (0,145) +1,549 (0,002) + 1,675 (0,006) + 0,837 (0,003) + 4,187 (0,844) = 3,76 kJ/kg.K

Steam Table

Q= 𝑚𝐶𝑝 𝑇2− 𝑇1 = ms(hg – hf)

ms = Q/ (hg – hf)

ms = Q/hfg

ms = 11280 kJ

2243.54 kJ/kg

ms = 5.03 kg

THANKS FOR YOUR ATTENTION

The best person is one give something useful always

28/04/2017 Nur Istianah-KP1-neraca energi-2015

MATERI KULIAH BISA DIUNDUH DI:

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