steam plant

Question 1

how to find steam quality

Answer 1

Assume isotropic expansion

s2=s3’

Question 2

finding x3’

Answer 2

x3’=((s3’-sf)/(sg-sf))

Question 3

finding h3’

Answer 3

h3’=hf+x3’*hfg

Question 4

finding h3

Answer 4

use thermal efficiency equation

nth=((h2-h3)/(h2-h3’)

Question 5

finding x3

Answer 5

(h3-hf)/hfg

Question 6

When quality of steam is close to one it is…

Answer 6

just dry saturated.

Question 7

specific enthalpy change across plant

Answer 7

qin=h2-h1
wt=h2-h3
wp=0 usually
qout=h3-h1

Question 8

net power output of turbine

Answer 8

Wnet= ṁ(h2-h3)

Question 9

thermal efficiency of rankine cycle

Answer 9

nth=Ẇt/Q̇in

Question 10

Thermal efficiency when pumps and others involved

Answer 10

nth=
(Ẇout+Qout)/Q̇in
-significant improved thermal efficiency but dictated by the Q̇out usage

Question 11

Energy Balance equation

Answer 11

hout=(y)hin1+(1-y)hin2

or similar

Question 12

What improvements can be made to a plant?

Answer 12

-Will generate large quantities of heat for district heat scheme, at a reduction to the power generation in LP turbines.
-May be much more cost effective if constant heating demand.
-The use of reheating cycle and combined feedwater heater could improve the system performance.
-Have a low superheat temperature.
-Overall plant thermal efficiency, can be calculated using
nth= Q̇out+Ẇelectricity
-this will show significant improvement