int. j. engg. res. & sci. & tech. 2014 rahul kumar singh ... · pdf filea systematic...

302

This article can be downloaded from http://www.ijerst.com/currentissue.php

Int. J. Engg. Res. & Sci. & Tech. 2014 Rahul Kumar Singh et al., 2014

EFFECT OF STEAM INLET TEMPERATUREON PERFORMANCE OF PARTIAL ADMISSION

STEAM TURBINE

Rahul Kumar Singh1*, Abhishek Arya2 and Sphurti Sweta Pandey3

Energy analysis helps designers to find ways to improve the performance of a system in amany way. Most of the conventional energy losses optimization method are iterative in natureand require the interpretation of the designer at each iteration. Typical steady state plant operationconditions were determined based on available trending data and the resulting condition of theoperation hours. The energy losses from individual components in the plant is calculated basedon these operating conditions to determine the true system losses. In this, first law ofthermodynamics analysis was performed to evaluate efficiencies and various energy losses. Inaddition, variation in the percentage of carbon in coal content increases the overall efficiency ofplant that shows the economic optimization of plant.

Keywords: Steam inlet temperature, Energy losses, Economic optimization

*Corresponding Author: Rahul Kumar Singh [email protected]

INTRODUCTIONPower plants are part of the infrastructure of the

modern society and it is essential that these

power plant facility by constructed so as to

achieve a higher level of reliability. Moreover it is

mandate of power plants involved in this industry

to contribute to society by realizing higher

performance. Energy analysis helps designers

to find ways to improve the performance of a

system in a many ways. Most of the conventional

energy losses optimization method are iterative

in nature and require the interpretation of the

designer at each iteration. Typical steady state

1 M.Tech Scholar, SCOPE Engineering College, Bhopal, India.2 Assistant Professor, SCOPE Engineering College, Bhopal, India.3 M.Tech Scholar, BITS, Bhopal, India.

Int. J. Engg. Res. & Sci. & Tech. 2014

ISSN 2319-5991 www.ijerst.comVol. 3, No. 4, November 2014

© 2014 IJERST. All Rights Reserved

Research Paper

plant operation conditions were determined based

on available trending data and the resulting

condition of the operation hours.

LITERATURE REVIEWGhosh et.al. (2005) states that the limited primary

energy sources and awareness of environmental

pollution has led to ever increasing end over to

develop new steam turbine power plants with the

highest possible efficiency. Considering their

output, even small step increase in efficiency can

result in major saving for the customers. As

overall cycle efficiency is strongly dependent on

303



steam turbine performance, Continuous

improvement are sought to increase the turbineefficiency. These effectors are directly primarilytowards improvements are blading as the keycomponent of the turbine

Kenji Nakamura et.al (2010) response to globalenvironmental issues, higher efficiency andimproved operational reliability are increasinglybeing requested for steam turbines, essentialequipment for thermal power generation. Byincreasing the temperature and pressure of thesteam turbine operating conditions, more efficientpower generation is realized, and in order torealize a turbine applied with the highertemperature conditions of 700oC for the future,Fuji Electric is participating in the METI-sponsoreddevelopment of advanced ultra-supercriticalpower generation, and is evaluating and verifyingthe reliability of materials used for high-temperature valves.

Paul I. Nippes et al. (2002) worked with thecurrent practices of extending periods betweenturbine-generator planned outages is the need forimproved and careful condition monitoring. Bydetermining the condition of the turbine generatorunits and their suitability for continuingsatisfactory operation, outages can be scheduled,often preventing forced outages. A relativenewcomer to the field of monitoring is shaftcondition monitoring, which also usually projectsto train condition monitoring. This is accomplishedby placing reliable shaft-riding brushes for shaftgrounding and voltage monitoring. As can beimagined, a wide plethora of shaft groundingcurrent and voltage data is available so the issuebecomes one of sifting through to identify andproject hidden messages as to the shaft, and unitcondition. Illustrations and descriptions of shaftgrounding currents and shaft voltages, based onmeasurements made on installed units is themain purpose of this paper.

PARTIAL ADMISSIONPartial admission applied as control stage yields

high part load efficiency and high specific work

output due to a maintained high inlet pressure for

the turbine in the fully admitted sectors. The

thermodynamics of partial admission can be

explained by a comparison to simple throttling

valve, as illustrated in Figure 1, where it is noted

that the average entropy of the steam into the

subsequent stage is lower for the control stage

than for a simple throttling valve due to the

maintained large pressure ratio across the open

admission arcs.

EXPERIMENTAL SETUPThe equipment has a data acquisition system to

collect the information. A systematic block

diagram of the experimental system is shown in

Figure 1.

Figure 1: Experimental Set up

The location and function of the data

instruments of the setup is given below:

Digital flow meter and display gauges

mounted on the steam supply lines are used to

measure and display the f low rate and

temperature of the steam. Controller monitored

pressure display is used to display the set point

and acquired pressure. Analog pressure gauges

mounted at various locations on the apparatus

304



are used to measure and display the pressure of

the steam or water. Thermocouples mounted on

the condenser unit are used to measure the

temperature of steam entering condenser, water

entering condenser and water leaving condenser.

Experimental Procedure

1. At the moment of taking the readings, the

steam turbine will be operational in the no load

condition. So, the first step is to set the 1/2 of

the maximum load applied on the turbine by

the generator.

2. Allow the system to reach steady state, and

take readings. They are:

a) Turbine inlet temperature.

b) Turbine exit temperature.

c) Turbine inlet pressure.

d) Turbine exit pressure.

e) Mass of steam flow.

f) Time operation.

3. The above procedure is repeated for the 3/4

of the maximum load applied.

4. Finally apply the full load to the turbine and

allow the system to reach up to the steady

state. Now take the readings at full load.

Assumptions

As per literature survey, the following

assumptions are considered for the efficient

operation of power plant.

· Each component of the cycle is analyzed as

a control volume at steady state.

· The turbine operated adiabatically.

· Saturated vapor enters the turbine.

· Condensate exits the condenser as saturated

liquid.

· In calculating the turbine efficiencies, the

enthalpies at the relevant state points were

taken

Full Load Steam Turbine Performance

The load on the turbine is a variable that can affect

the output power and the efficiency. The load is

a number between 0 and 100, and it represents

a braking or drag resistance to the shaft rotation.

The greater the load, the greater the resistance

applied. The load affects the power output

because it influences the RPM and the mass flow

rate of the steam. For any steam turbine, if there

is increase in the load, the RPM will be going to

plummet unless the mass flow rate is increased.

Effect of Steam Inlet Temperature

Enthalpy of steam is a function of temperature

and pressure. At lower temperature, enthalpy will

be low, work done by the turbine will be low,

turbine efficiency will be low, hence steam

consumption for the required output will be higher.

In other words, at higher steam inlet temperature,

heat extraction by the turbine will be higher and

hence for the required output, steam consumption

will reduce. Figure 3 represents the effects of

steam inlet temperature on steam consumption,

keeping all other factors constant for the

condensing type turbine.

RESULTSFigure 2: Effect of Steam Temperature on

Steam Consumption

9 8 . 2 9 8 . 4 9 8 . 6 9 8 . 8 9 9 . 0 9 9 . 2 9 9 . 4 9 9 . 6 9 9 . 8 1 0 0 . 02 9 0

3 0 0

3 1 0

3 2 0

3 3 0

3 4 0

3 5 0

3 6 0

3 7 0

3 8 0

Ste

am te

mpe

ratu

re (

de

g C

)

S t e a m C o n s u m p t i o n %

305



Figure 3: Effect of Steam Temperatureon Turbine Efficiency

290 300 310 3 20 330 340 350 360 370 38033 .0

33 .2

33 .4

33 .6

33 .8

34 .0

Tu

trb

ine

Eff

icie

ncy

%

S te am T e m p e ratu re (de g c )

EFFECT OF STEAM INLETTEMPERATURE AT 75% LOAD

Figure 4: Effect of Steam Temperatureon steam consumption

7 3 7 4 7 5 7 6 7 7 7 8 7 9 8 0 8 12 9 0

3 0 0

3 1 0

3 2 0

3 3 0

3 4 0

3 5 0

3 6 0

3 7 0

3 8 0

Ste

am

Te

mp

era

ture

(de

g c

)

S te a m C o n s u m p t io n %

2 2 .0 22 .2 2 2 .4 2 2 .6 22 .8 2 3 .0 2 3 .22 9 0

3 0 0

3 1 0

3 2 0

3 3 0

3 4 0

3 5 0

3 6 0

3 7 0

3 8 0

Ste

am T

emp

era

ture

(de

g c

)

T u rb in e E ffic ie n cy %


EFFECT OF STEAM INLETTEMPERATURE AT 50% LOAD

5 2 5 3 5 4 5 5 5 6 5 7 5 82 9 0

3 0 0

3 1 0

3 2 0

3 3 0

3 4 0

3 5 0

3 6 0

3 7 0

3 8 0

Ste

am T

em

pera

ture

(deg

c)

S te a m C o n s u m p t io n %

Figure 6: Effect of Steam Temperatureon steam consumption

1 8 .0 1 8 .2 1 8 .4 1 8 .6 1 8 .8 1 9 .0 1 9 .2 1 9 .42 9 0

3 0 0

3 1 0

3 2 0

3 3 0

3 4 0

3 5 0

3 6 0

3 7 0

3 8 0

Ste

am T

em

pera

ture

(deg

c)

T u rb in e E f fic ie n c y %


CONCLUSIONSteam Turbines are one of the main energy

consuming equipments, even though not much

attention is paid to them. Trimming of operating

parameters are essential for efficient operation

of these turbines. Illustration given in the work

shows impact of operating conditions on steam

turbines. Savings presented are for a typical

operating conditions.

REFERENCES1. Eck M, and Zarza (2006), “Saturated steam

306



process with direct steam generating

parabolic troughs”, Solar Energy, Vol. 80,

pp. 1424–1433.

2. Fan T, Xie Y, Zhang D and Sun B (2007), “A

Combined Numerical Model and

Optimization for Low Pressure Exhaust

System in Steam Turbine,” ASME Power

Conference, San Antonio, TX, July 17–19,

ASME Paper No. POWER2007-22147.

3. Ghosh T K A G M and Bansal P K S M

(2005), “Latest Trends In Large Rating

Steam Turbine Blading”, BHEL, Hardwar.

4. Kenji Nakamura, Takahiro Tabei and Tetsu

Takano (2010), “Recent Technologies for

Steam Turbines”, Energy Solution Group,

Fuji Electric Systems Co., Ltd.

5. Kyoung Hoon Kim and Giman Kim

(2010),”Thermodynamic Performance

Assessment of Steam-Injection Gas-Turbine

Systems”, World Academy of Science,

Engineering and Technology, Vol. 44.

6. Owczarek J A, Warnock A S and Malik P

(1989), “A Low Pressure Turbine Exhaust

End Flow Model Study,” Latest Advances in

Steam Turbine Design, Blading, Repairs,

Condition, Assessment, and Condenser

Interactions, D M Rasmussen, ed., ASME,

New York, pp. 77-88.

7. Paul I Nippes P E and Elizabeth S Galano

(2002), “Understanding Shaft Voltage And

Grounding Currents of Turbine Generators’.

8. Tindell R, Alston T, Sarro C, Stegmann G,

Gray L and Davids J (1996), “Computational

Fluid Dynamics Analysis of a Steam Power

Plant Low-Pressure Turbine Downward

Exhaust Hood,” ASME J. Eng. Gas Turbines

Power, Vol. 118, pp. 214–224.

9. Xiaodong W A N G, Shun K A N G and Ke

YANG (2007), “Investigation of a Steam

Turbine with leaned blades by Through Flow

Analysis and 3D CFD Simulation”,

International Conference on Power

Engineering, October 23-27, 2007,

Hangzhou, China.

10. Xu X, Kang S and Hirsch C (2001),

“Numerical Simulation of the 3D Viscous

Flow in the Exhaust Casing of a Low-

Pressure Steam Turbine,” ASME Turbo

Expo, New Orleans, LA, June 4–7, ASME

Paper No. GT2001-0487

int. j. engg. res. & sci. & tech. 2014 rahul kumar singh ... · pdf filea systematic...

Documents