regenerative heating of the feed water (rhfw) · temperature on the inlet of steam turbine is...
TRANSCRIPT
![Page 1: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/1.jpg)
REGENERATIVE HEATING OF THE
FEED WATER (RHFW)
TOMSK POLYTECHNIC UNIVERSITY
![Page 2: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/2.jpg)
MAIN FEATURES
Theoretical cycle with heat regeneration
Real cycle with heat regeneration
Effect of RHFW on the efficiency of NPP
Distribution of regenerative bleed into turbine
Steam and drainage cooling
![Page 3: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/3.jpg)
EFFECT OF FEED WATER
TEMPERATURE ON EFFICIENCY
To improve efficiency of NPP the average temperature of heat
supplied to cycle should be increased. When ability to increase
temperature on the inlet of steam turbine is depleted this could
be reached by increasing the temperature of the feed water on
the inlet of steam generator.
The most efficient method to increase temperature on the inlet
of steam generator is application of regenerative heating of feed
water.
![Page 4: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/4.jpg)
REGENERATIVE HEATING OF THE
FEED WATER (RHFW)
Regenerative heating of the feed
water (RHFW) – application of
heat of working fluid, which have
conducted mechanical work in
turbine, on the different part of the
cycle.
Effect of RHFW:
Decreasing of the thermodynamic
irreversibility of heating on the
line k’-a’
Decreasing of heat losses into
cold source (condenser)
![Page 5: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/5.jpg)
THEORETICAL CYCLE WITH REGENERATIVE
![Page 6: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/6.jpg)
SCHEME OF THEORETICAL CYCLE
WITH REGENERATIVE HEATING
![Page 7: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/7.jpg)
FINITE THEORETICAL CYCLE WITH
REGENERATIVE HEATING
Finite theoretical regenerative cycle:
Infinite amount of regenerative bleeds;
Infinitively low heat drops at each stage.
Impossibility of theoretical regenerative cycle:
Unacceptable humidity in the end of expansion process;
Large dimensions of heaters, bleed cross-section area and
pipelines;
High pressure losses.
![Page 8: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/8.jpg)
THREE STAGE RHFW OF THE
OPEN TYPE
One stage of RHFW
includes:
Steam bleed;
Heater;
Steam pipeline;
Pump (optional);
Drain line (optional).
![Page 9: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/9.jpg)
SCHEME AND CYCLE OF TWO STAGE
RHFW OF THE CLOSED TYPE
![Page 10: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/10.jpg)
WORK OF TURBINE IN SCHEME
WITH TWO STAGE RHFW
Theoretical work:
lt=lI+lII+lk=(h0-h1t)+(1-α1)(h1t-h2t)+(1-α1-α2) (h2t-hkt)=h0- -α1 h1t-α2 h2t-αk hkt
Real work:
lt=lI+lII+lk=(h0-h1)+(1-α1)(h1-h2)+(1-α1-α2) (h2-hk) =h0- -α1 h1-α2 h2-αk hk
![Page 11: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/11.jpg)
PARAMETERS OF NPP IN SCHEME
WITH N-STAGED RHFW
Effective heat drop of turbine with nth stages:
By substituting we get:
0
1
np p
i i j j k k
j
l H h h h
0
1
np
i k j j k
j
H h h h h
1
1n
k j
j
![Page 12: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/12.jpg)
PARAMETERS OF NPP IN SCHEME
WITH N-STAGED RHFW
Coefficient of turbine power decreasing:
Turbine power using values of yj:
0
1 1
1n n
p
i k j j k i j j
j j
H h h h h H y
0
j k
j
k
h hy
h h
![Page 13: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/13.jpg)
EFFICIENCY OF NPP IN SCHEME
WITH N-STAGED RHFW
Efficiency of theoretical NPP with RHFW:
Efficiency of real NPP with RHFW :
0 010 0
1 0 0
np p
k kt j jtjp
t p
fw fw
h h h hH H
q h h h h
0 01
1 0 0
np p
k k j jjp i it p
fw fw
h h h hH H
q h h h h
![Page 14: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/14.jpg)
EFFECT OF RHFW ON NPP
EFFICIENCY
Energy coefficient with regeneration:
Efficiency of theoretical NPP with RHFW:
01
0
n
j jjp
k k
h hA
h h
1
1
preg p
i i p p
i
A
A
![Page 15: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/15.jpg)
EFFECT OF NUMBER OF RHFW
STAGES ON NPP EFFICIENCY
Increasing z results into increasing efficiency.
Maximal efficiency is obtained at optimal temperature of feed water.
Optimal temperature of feed water increases with z.
With increasing z the thermal efficiency decreases.
On practice the 7-8 stages of RHFW is applied. I allows to increase efficiency by 15-17 %.
![Page 16: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/16.jpg)
EFFECT OF NUMBER OF RHFW
STAGES ON NPP EFFICIENCY
Power of turbine of NPP with RHFW:
Steam flow rate on turbine with RHFW:
Note. Steam flow rate in NPP with RHFW is larger in comparison with NPP without regeneration.
1
1n
p
i i i j j
j
N G H G H y
1
1
i
n
i j j
j
NG
H y
1
11
1p n
j j
j
k
y
![Page 17: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/17.jpg)
CHOICE OF NUMBER OF BLEEDS
AND PRESSURE
To reach maximal thermal efficiency of NPP the
different methods could be applied.
![Page 18: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/18.jpg)
EVEN DISTRIBUTION OF HEATING
Assuming the heat taken from 1 kg of steam from
one heater to another to be constant the
maximal efficiency could be obtained at even
distribution of enthalpy increasing.
![Page 19: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/19.jpg)
EVEN DISTRIBUTION OF FEED
WATER ENTROPY
![Page 20: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/20.jpg)
EVEN TEMPERATURE RELATION
![Page 21: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/21.jpg)
INDIFFERENT POINT
![Page 22: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/22.jpg)
REGENERATION IN NPP WITH HEAT
SUPPLY
![Page 23: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/23.jpg)
CHOICE OF OPTIMAL TEMPERATURE
OF FEED WATER
Choice of optimal feed water temperature is complex technic-economic task.
Factors affecting regeneration parameters:
Specific power of equipment;
Initial parameters of steam;
Cost of materials and fuel.
Taking into account economic factors the amount of regenerative heaters is chosen to be 7-9 in Russia and up to 11 abroad. The technic-economic optimal temperature of feed water is lower than thermodynamic optimal.
![Page 24: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/24.jpg)
COMPARISON OF SURFACE-TYPE
AND MIXING HEATERS
![Page 25: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/25.jpg)
COMPARISON OF SURFACE-TYPE
AND MIXING HEATERS
![Page 26: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/26.jpg)
MIXING HEATERS
Advantages:
Simplicity;
Lower cost;
Higher reliability;
Simplicity of exploitation and repairs;
Lesser concentration of metals and oxides.
NO UNDERHEATING.
Disadvantages:
Need for additional pumps;
Need for additional protection from droplets entering turbine (hard to realize at high pressures).
![Page 27: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/27.jpg)
SCHEMES OF MIXING HEATERS
The heaters of mixing type is applied for the first
two steps of regenerative heating.
![Page 28: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/28.jpg)
SURFACE HEATERS
Advantages:
Independence of steam and water pressures;
Possibility to apply one pump.
Disadvantages:
Complexity;
Lesser reliability;
Higher costs;
UNDERHEATING.
![Page 29: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/29.jpg)
SCHEMES OF SURFACE HEATERS
The heaters of mixing type is applied for the first
two steps of regenerative heating.
![Page 30: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/30.jpg)
COMPARISON OF SCHEMES
Scheme Advantages Disadvantages
A Maximal efficiency Many pumps pumping water with
high temperature
B Simplicity
No pumps needed
Steam condensate push out
steam from next heaters
Additional losses into condenser
C Intermediate solution between schemes A and B
Aim: decrease “pushing out”
Main feature: temperature of condensate in drainage
cooler is higher by 10-15 °C in comparison with feed water temperature.
D
![Page 31: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/31.jpg)
STEAM COOLER
Temperature of steam after steam cooler is higher by 10-15 °C than saturation temperature.
Application of steam cooler gives:
higher feed water temperatures on the outlet;
increased efficiency of regeneration;
increased bleed steam consumption.
![Page 32: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/32.jpg)
DRAINAGE/CONDENSATE COOLER
![Page 33: REGENERATIVE HEATING OF THE FEED WATER (RHFW) · temperature on the inlet of steam turbine is depleted this could be reached by increasing the temperature of the feed water on the](https://reader034.vdocuments.us/reader034/viewer/2022051920/600cee1c68ad7a65b82cebde/html5/thumbnails/33.jpg)
THANK YOU FOR YOUR ATTENTION