19-04-2012, 04:51 PM
Vapour Power Cycles
2_%20Rankinecycle.pdf (Size: 115.64 KB / Downloads: 449)
Reasons for Considering Rankine Cycle as an Ideal Cycle For Steam
Power Plants:
1) It is very difficult to build a pump that will handle a mixture of liquid and vapor
at state 1’ (refer T-s diagram) and deliver saturated liquid at state 2’. It is
much easier to completely condense the vapor and handle only liquid in the
pump.
2) In the rankine cycle, the vapor may be superheated at constant pressure from
3 to 3” without difficulty. In a Carnot cycle using superheated steam, the
superheating will have to be done at constant temperature along path 3-5.
During this process, the pressure has to be dropped. This means that heat is
transferred to the vapor as it undergoes expansion doing work. This is difficult
to achieve in practice.