Download - Chem. Eng. Thermodynamics (TKK-2137)
Chem. Eng. Thermodynamics(TKK-2137)
14/15 Semester 3
Instructor: Rama OktavianEmail: [email protected] Hr.: M.13-15, Tu. 13-15, W. 13-15, Th. 13-15, F. 09-11
Outlines
1. Heat engine (Power from heat) 1. Heat engine (Power from heat)
2. Steam power plant 2. Steam power plant
3. Carnot cycle power plant 3. Carnot cycle power plant
4. Rankine cycle power plant 4. Rankine cycle power plant
Heat engine
HE
TH
TC
W
QC
QH
CH QQW
Thermal efficiency:
h = -----------------------Heat absorbed
Net work output
H
CH
H Q
Q
W h
H
C
Q
Qh 1
For 100% efficiency, QC = 0(impossible)
Heat engine
Production power from heat:
The potential energy of tides - possible source of power
hydroelectric power is generated by conversion of the potential energy of water into work
Combustion of fuel – the most important power source: - power plant : steam power plant, coal power plant, NG power plant
Internal combustion engine: -Otto and Diesel engine
Steam power plant
Carnot cycle for steam power plant:idealized cycle would be represented on t-s diagram
1 2 is the vaporization process
2 3 is a reversible, adiabatic expansion of saturated vapor into the two-phase region
3 4 is a partial condensation process
4 1 takes the cycle back to its origin
Ideal Rankine cycle
simplest real power plant cycle is Rankine cycle
pump, 4 - 1 boiler, 1 - 2 turbine, 2 – 3 condenser,
3 - 4
Rankine cycle
increase η – increase boiler pressure increase in pressure has QH entering at higher t trade-off occurs
due to change in Δs
Cengel, Y. A., Introduction to Thermodynamics and Heat Transfer, McGraw-Hill,1997
Rankine cycle
increase η – lower condenser pressureTHIS RESULTS IN MORE AVAILABLE WORK
Cengel, Y. A., Introduction to Thermodynamics and Heat Transfer, McGraw-Hill,1997
Rankine cycle
increase η – SUPERHEATING STEAM superheating steam gives a higher TH for QH addition. also avoids condensing in the turbine.
Cengel, Y. A., Introduction to Thermodynamics and Heat Transfer, McGraw-Hill,1997
Rankine cycle
increase η – INTERMEDIATE REHEAT CYCLE MULTIPLE REHEAT STAGES ARE POSSIBLE REDUCES CONDENSATION AT THE TURBINE DISCHARGE
Cengel, Y. A., Introduction to Thermodynamics and Heat Transfer, McGraw-Hill,1997
Rankine cycle
Regenerative Rankine Cycle
this method can increase the boiler feed water temperature but it lowers steam flow to the turbine