NASA Technical Memorandum 81611

{:.NASA-£i{-S]611) OFF-DESIGN ANALYSIS OF A_:_AS TGt_.8]'NE POWE_LANT AUGMBNTED BY ST_.A.M

E

lil]d_,.%'XON USING VARIOUS _UELS (NASA) 29 pHC I O._/MY A01 CSCL 10B

N81-16571

Unclas

_1169

Off-Design Analysis ofa Gas.. Turbine

Powerplant Augmented by SteamIr_jection Using Various Fuels

kobcrt J. Stochl

_cea'is Research Center

ci;:.,Jeland, Ohio

l

j

"i' • "

' i

iNovember 1980

https://ntrs.nasa.gov/search.jsp?R=19810008054 2018-05-17T19:43:06+00:00Z

OFF DESIGN ANALYSIS OF A GAS TURBINE POWER PLANT AUGMENTED BY

STEAM INJECTION USING VARIOUS FUEL TYPES

by Robert J. Stochl

National Aeronautics and Space Administration

Lewis Research Center

Cleveland, Ohio 44135

SUMMARY

The results of an analysis to estimate the off-design performance of a

specific gas turbine powerplant with steam injection are presented. Results

were obtained using coal-derived low and intermediate heating value fuel gases

and a conventional distillate. The turbomachinery characteristics used in the

calculation of off-deslgn operation were scaled from available performance maps

of aircraft type gas turbines.

The results indicate that steam injection does provide substantial in-

creases in both power and efficiency within the available compressor surge

margln. The results also indicate that the increase in performance with steam

injection is insensitive to the type of fuel. Also, in a eogeneration applica-

tion, steam injection could provide some degree of flexibility by varing the

sp]it between power and process steam.

INTRODUCTION

A concept for simultaneously increasing the power output and efficiency of

a gas turbine is based on the injection of steam into the combustor of the gas

turbine. Steam injection increases the power output of a gas turbine by incres-

ing the mass flow (and its specific heat) through the turbine without signifi m

cantly increasing the power required to drive the compressor. If the steam is

generated by recovering otherwise wasted heat from the gas turbine exhaust, the

power system efficiency would also be increased. From this standpoint a steam-

injected gas turbine cycle is thermodynamically similar to a combined gas-

turbine - steam-turbine cycle. However, the steam portion of the steam injected

cycle operates at much lower pressure levels, and higher temperature levels than

the steam portion of a conventional combined cycle. It also has a potential

cost advantage of not requiring a separate steam turbine generator or its heat

rejection system.

Several investigators (refs. 1 to 4) have analytically shown that a con-

siderable increase in performance (both power and efficiency) can be achieved

by injecting steam into the combustor of a gas turbine. Although the authors

of reference 2 did consider a variation in compressor-pressure ratio with

increased mass flow, most analyses have estimated the performance of a gas

turbine at each steam injection rate assuming design-point performance. They

ORiGli"_,m,!.. FAGE 15

OF POOR QUALITY

..... , | ,

have not included the analysis of a fixed set of hardware for a variation in

the amount of injected steam. A potential advantage of steam-injection gas

turbines is the ability to change power level bY changing the steam-injection

rate, while holding the turbine-i_11et temperature at a constant value. This

could result in attractive performance over a range of power outputs for a

fixed machine.

One purpose of this investigation was to determine the effect of steam

injection on the performance of a gas-turbine system using turbomachinery not

specifically designed for steam injection. The system operating parameters

(such as turbine-inlet temperature and compressor-pressure ratio), used in this

report were based on presently available, advanced, single-shaft, heavy-duty

gas turbines. The turbomachinery characteristics used in the calculation of

off-design operation were scaled from available performance maps of aircraft-

type gas turbines. These maps would not necessarily match those of heavy-duty

industrial gas turbines but should be suitable to indicate the proper trends

and to assess the potential performance advantages in using steam injection in

gas turbines.

When the mnount of steam injection is increased in a particular fixed-

geometry gas turbine, the turbine flow increases relative to the compressor

flow, increasing the compressor back pressure and moving the compressor pres-

sure ratio toward the surge line. The initial surge margin available to the

compressor depends on its design operating point. Because the operating point

of a particular gas turbine might be different when used with a coal-derlved

gaseous fuel compared with a conventional liquid fuel, it is of interest to

consider a variety of fuel types in assessing the advantages of steam injection.

Also, in a power system integrated with a sasifier, it might be necessary to

start up using a fuel other than that produced by the gasifier or to be able to

operate on a second fuel if the gasifier for some reason must be shut down.

Therefore, the per.formance of a specific gas turbine with steam injection was

considered using coal derived low and intermediate heating value fuel gases,

as well as a conventional distillate. Systems using low heating value fuel

from both an atmospheric gasifier and from a pressurized gasifier were _onsid-

ered. The emphasis here is not to evaluate or compare gasifier designs but to

determine the effect of the fuels obtained from the various gasifiers. Calcu-

lations were performed assuming that the turbomachinery operated at the design

point for only one of these fuels. The operating point was then calculated for

each of the other fuels. In each case a range of steam injection rates were

considered. Two sets of such calculations were made: one assuming that the

turbomachinery operated at its design point when low heating value fuel from

an atmospheric gasifier is used, the other assuming that intermediate heat-

ing value fuel from a pressurized gasifier is used.

The turbine-lnlet temperature was assumed constant at 1093 ° C (2000 ° F).

The effects of turbine cooling were not included in the analysis. The inlet

steam conditions to the combustor were assumed to be 482 ° C at 1.379 MPascal

(900 ° F at 200 psia) in all cases.

DESCRIPTIONOFSYSTEMSANDASSUMPTIONS

Four basic gas turbine system configurations were evaluated. The basicdistinction between the four configurations is the type of fuel used.

Configuration i - Simple steam-injected gas turbine fueled by the products ofan air-blown coal gasifier operating at atmospheric pressure.

Configuration 2 - Simple steam-.injected gas turbine fueled by the products ofan air-blown pressurized coal gasifier.

Configuration 3 - Simple steam-injected gas turbine fueled by the products ofan oxygen-blown pressurized coal gasifier.

Configuration 4 - Simple steam-injected gas turbine fueled by a lightdistillate.

Configuration i is shownschematically in figure l(a). Ambient air at 16° C(60° F) and 0.010 MPascals (14.7 psia)) is pressurized in a compressor, heatedin the combustor together with injected steam by the burniug of fuel from thegasifier, and expandedin the turbine. The turbine drives the compressor andgenerator. The heat in the turbine exhaust is used to raise 482° C (900° F),1.379 MPaseal (200-psia) steam in a heat recovery boiler, a portion of whichis used for steam injection (the remainder could be used as process steam).The turbine-inlet temperature wasmaintained at 1093° C (2000° F) in all cases.The fuel from the gasifier was assumedto enter the gas turbine combustor at316° C (600° F) and at a pressure 0.334 MPascals (48.5 psia) above the compres-sor exit pressure. The composition of the fuel going into the combustor isgiven in table I for each configuration. The auxiliary power requirement in-cluded in this configuration was that required to raise the low heating valuefuel gas to a p_essure 0.334 MPaseals (48.5 psia) above the main compressor-discharge pressure.

Configuration 2 (fig. l(b)) is similar to configuration i except that thepressurized air required by the gasifier is supplied from the gas-turbine com-pressor. The auxiliary power requirement included in this configuration is thepower necessary to increase the air supply pressure by 0.334 MPascals (48.5psia) in a boost compressor. The gasifier air input to fuel output ratio(Ma2/Mf - 0.7628) and fuel gas composition as shownin table I were assumedconstant and unaffected by gasifier pressure level.

Configuration 3 (fig. l(c)) is a simple gas turbine fueled from an oxygen-blown pressurized ga_ifier. The oxygen is produced from air and pressurized tothe operating pressure level of the gasifier (P + 0.334 MPascals (48.5 psia)).The gasifier was assumedto require 0.291 kilograms of oxygen per kilogram in-termediate heating value fuel output. The fuel composition of the intermediateheating value fuel into the gas turbine combustion is given in table I. Theauxiliary power requirements for this configuration were assumedto be(i) 0.255 kilowatt-hour ker kilogram of atmospheric pressure oxygen produced inthe oxygen plant and (2) the power required to pressurize the oxygen to thegasifier operating pressure.

" __'- ':"i ::"71

Configuration 4 (fig. l(d)) is a simple steam injected ga:_ turbine u.,_lng

a light distillate fuel. Fuel system auxiliary power would be relaLlvely small,and was no_: included.

It was assumed Cor all cases that tile gastfJert_ were capable of operating,

without change iu efficiency, over the range of fuel f tow rates required by tim

gas turbine for tile w_rious steam injection rates. The lower stack g_L:_ temper-ature limit for the turbine exhaust was assumed to be ]49 ° C (300 ° F). This

limit, as will be discussed later, in al.l but two cases restricted tile maximum

amount of 482 ° C (900 ° F) steam that could be produced by recovering heat from

the turbine exhaust.

With the exceptiou of configuration 4, each of the fuel supply systems ar_,

in various degrees integrated with the power conversion system. It is |lot tile

purpose of this report to evaluate or compare tile var[ou:_ gasifler systems.

However, to properly compare system perforl_mnce for the various fuels some ¢ou-

sideration of gasifierperformancewas required. Included in the net work output

of the gas turbine systems are the auxiliary power requirements needed to supply

tile fuel gas to the gas turbine combustor at a pressure of 0.334 blPascals (48.5

psia) above combustor pressure. Auxiliaries associated with coal preparation

or fuel gas cleml up were not included. Figure 2 is an energy flow diagram for

each of the three coal derived fuel systems. These data are the result of a

heat balance of a fluid l_ed gasifier with cold gas clean up, In figure 2(b)and (c) the fuel gas is reheated by recuperation to 31b ° C (bOO ° F). In each

gnsifior steam is produced [n the process of cooling the fuel gas. Any part of

this steam could be used for steam injection into the gas turbine combustor.

To arrive at tile system efficiency tile gas turbine cycle efficiency was

multiplied by the effective efficiency, 'lg, of the fuel supply systems. The

_g is equal to the fuel energy input to tile gas turbine (Q_I,(IT) divided by the

coal energy input to the fuel supply system (Q_,coal.) and Qq,(,T is based on

only the higher heating value of the fuel gas and (!q,eoal is based on tilehigher heating value of Illinois number 6 coal 28.40 blj/Kg (12 235 Bttl/lb).

For coufigurations 1 and 2 _g = 0.760, for configuration 3 _g = 0.806.

As mentioned i,i tile introduction, two sets of calculations were made. One,

designated design option I, is where system configuration i (without steam ill-

jection) operated with the parameters listed in table II. Configurations 2 to

4, with and without steam injection, as well as configuration 1, with steam

injection, were then considered as operating ill an off-design mode. The second

set of calculations, design option 2, is where configuration 3 (without steam

injection) operated with tile parameters listed in table li. ltere, configuration

1, 2, and 4, with .qnd without steam injection, as well as configuration 3, withsteam injection, were operated in an off-desigtl mode. All calculations were

performed using the compressor and turbine characteristics shown in figures 3.

These characteristics, obtained by sealing a large aircraft-type turbomachine

to an indt|strial size operating with tile chosen design pnrameters, apply to a

single-shaft gas turbine operating :it its design speed. The pressure lossesfor each component with the addition of steam injection and the other fuels

were assumed to change according to tile retatton

i, i

1.75 2

where

M is the mass flow rate,

T is the inlet temperature,

P is the inlet pressure,

AP is the component pressure drop,

and the subscript d indicates design condition.

DESIGN OPTION 1 RESULTS

The effect of fuel type on the performance of design option I turbomachin-

cry is shown in table III. As stated previously, design option i turbomachinery

was sized for the parameters listed in column 1 (configuration i). The results

shown are without steam injection (Ms/M a = 0). There is a 28 to 35 percent de-

crease in the gross output for configurations 2 to 4 compared with configura-

tion i. The design fuel to air ratio for configuration i was 0.257. This

means there is 25.7 percent more mass flow through the turbine than through the

compressor, resulting in a higher gross work output per pound of airflow. As

the heating value of the fuel increases (for intermediate Btu and light dis-

tillate fuels), the fuel to air ratio required to maintain 1093 ° C (2000 ° F)

turbine inlet temperature decreases (i.e., (F/A)con f 3 = 0.076 and (F/A)con f 4

= 0.022) which lowers the gross specific work output. However, when the auxil-

iary power required to compress the fuel and/or oxidizer are deducted from the

generator output, the resulting difference in net power between configuration i

and the other three is reduced 12 to ]5 percent. It should be noted that the

relatively small amount of auxiliary losses shown for configuration 2 results

because a major portion of the power required for the pressurization of the

oxidizer is supplied by the gas turbine compressor and is, therefore, included

in the determination of the gas turbine generator output•

There are three efficiency values shown in table III. Gas turbine effi-

ciency (nGT), which is defined as the generator output divided by the energyinput to the gas turbine combustor based on the higher heating value of the

fuel gas. Cycle efficiency (_Cycle) is the generator output minus the auxil-iary power required for motor driven air or fuel gas compressors (net power

output), divided by the energy input to the gas turbine combustor. And system

efficiency which is, except for configuration 4, the net power output divided

by the coal energy input to the gasifier based on the higher heating value of

the coal. For configuration 4 the light distillate fuel was assumed not be

derived from coal and to require no auxiliary power so the three efficiency

values are the same. The gas turbine efficiency is also highest for configur-

ation i. This is to be expected since the turbomachinery in the other config-

urations would be operating at an off-design point with other compressor

effieiencies and lower pressure ratios. Once the auxiliary losses and gasifier

efficiencies are included, the cycle and system effic_encies are higher for theintermediate heating value and light distillate fuels (configurations B and 4).The detailed performance results usin_ steam injection are tabulated intable IV. The performance results are presented in figures 4 to 6.

Figure 4 illustrates the effect of steam injection on the net power outputfor the four configurations. The trend for all configurations is an approxi-mately linear increase in net power for increasing steam to air ratios. Thereis approximately an 8 electrical megawatt (MWe)increase in powe_for each 0.iincrease in the steam to air ratio. The maximumamount of steam that can beinjected into the combustor is limited by the surge margin of the compressorThe compressor-pressure ratio increase toward the surge line as the _team-injection rate increases. The steam to air ratio at which compressor surge isencountered is indicated in figure 4. It varies from a steam to air ratio ofslightly more than 0.2 for configuration i to 0.5 for configuration _. In allconfigurations steam can be produced by recovering the heat i ..... e turbineexhaust. In the configurations using the coal-derived fuel gases (configura-tions i to 3) additional steam is generated in the gasification process. (Seefig. 2,) The limits on the steam to air ratios for these two steam-generatlngsources are also indicated in figure 4. For configuration i the compressorsurge limit is reached before the steam generating capacities are exceeded.For configurations 2 to 4 the steam raising capability in the turbine exhaustlimits the steam to air ratio to approximately 0.22. For configuration 2 thissteam to air ratio can be increased to 0.37 by also using steam produced in thegasification process, while the steam to air ratio for configuration 3 can onlybe increased to 0.26 using gasification steam. The performance results thatfollow, for design option i, will be restricted to the appropriate limitingsteam air ratios.

Figures 5 and 6 present the cycle and system efficiencies over the appro-priate stea9 to air ratios. The trend for all configurations is increasing

cycle and system efficiencies for increased steam to air ratio. There is

approximately a 32-percent increase in system efficiency (fig. 6) for config-

uration i for its limiting steam to air ratio. For configurations 2 to 4 there

is approximately a 40 to 62 percent increase.

It should be noted that the system efficiency for the light distillate fuel

(configuration 4) is considerably higher than for the coal derived fuels, be-

cause that power system was not charged with any fuel conversion efficiency or

any auxiliary power losses connected with the supply of fuel. If the light

distillate was derived from coal the system efficiency values shown would then

have to be modified by a conversion efficiency factor which would bring them

more in line with other coal derived fuels. If the light distillate was not

derived from coal its cost of power would be higher than the coal derived fuels.

Figure 7 is a composite of figures 4 and 6, that illustrates the relation

of system efficiency, net power output, and steam to air ratio. With steam

injection the percent increase in efficiency is less than the percent increase

in net power output due to the additional fuel required to heat the injected

steam to the turbine-inlet temperature. In a cogeneration application the heat

in the turbine exhaust might also be used to generate steam for process use as

_i_i_! i_r_

well as for injection. Also, the steam generated in the gasification processcan be used for either injection or process. To follow a variation in powerversus steam requi_'ements, it might be desirable to vary the amountof steaminjection versus the amount of steam used for process.

Figure 8 illustrates the relation between steam available for process useand the steam used for injection into the combustor. Two sets of results areshown. Oneis the result of using only the steam produced by reducing theturbine exhaust to the limiting stack temperature. The other is the result ofusing the steam produced from the turbine exhaust plus steam available from theparticular gasifier. The maximumamount of 482° C (900° F), 1.379 MPascals(200-psia) steam that could be raised with and without gasifier steam is shownalong the Ms/Ma = 0 coordinate. The amount of available process steam de-creases linearly for increased injection ratios until all the steam raised isused for injection, or in the case of system configuration I, the compressorsurge limit is reached. The difference between the two sets of results is thesteam produced in the gasification process. Both low heating value gasifica-tion subsystems produce considerably more ste_n than the intermediate heatingvalue subsystem. The poundsof steam per poundof fuel gas output are slightlyhigher for the low heating value subsystem (0.458 and 0.368 for the atmosphericand pressurized low heating value subsystem, respectively, comparedwith 0.309for the intermediate heating value system). However, the total fuel requiredusing the low heating value fuel gas is more than three times that required ofthe intermediate heating value gas, resulting in much larger total steamproduction.

The relation between the total steam available (including any steamgener-ated in the gasification process) for process use and net power is illustratedin figure 9 over the allowable range of steam to air ratios. This figure is acomposite of figures 4 and 8. This information illustrates the potential abil-ity of these systems to follow variation in power versus steamrequirements.Both the net power and process steam production is greatest for system config-uration 1 at any given steam to air ratio, followed by configurations 2 and 3.

Configuration 4 produces less steam than configuration 3 but slightly more

power,

DESIGN OPTION 2 RESULTS

The effect of fuel type on the performance of design option 2 is shown in

table V. Design option 2 turbomachinery was sized for configuration 3 using

the parameters listed in the second column. The basic comparisons shown are

again for a steam to air ratio of zero. Configuration i was eliminated from

this option because it was unable to operate below the compression surge point.

The net power output for the remaining configurations were all approximately

20 MWe. The gas turbine efficiency for the design configuration (intermediate

heating value fuel) is approximately the same as obtained using the light dis-

tillate. But, again, once the auxiliary losses ana gasifier efficiencies are

included, the cycle and system efficiencies are higher for the configuration

using the light distillate fuel. The cycle and system efficiencies of the low

heating value fuel configuration w_re the lowest of the three cases.

The detailed performance results for option 2 with steam it%J_ction arepresented in table VI, and in figures I0 to 12. Figure i0 illustrates theeffect of steam injection on the net power output for the three configurations.There is not a significant difference in net power output between the configur-ations at any steam to air ratio. The trend for all cases is again a linearincrease in power for increasing injection rates. There is, again, approxl-mately an 8-MWeincrease in power for each 0. i increase in the steam to airratio. The values of the steam to air ratio at which compressorsurge isencountered and at which the limit of the steam raising capability of theturbine exhaust is encountered are indicated. For configuration 2 the surgelimit is encountered before the steam raising limit. For configuration 3 thesurge limit and steam raising capability limit both occur at a steam to airratio of approximately 0.20. For configuration 4 the steam raising limit ofthe turbine exhaust occurs well before reaching compressor surge. Additionalsteam is not available for this configuration as it is in the coal-derived fuelgas ca_es.

Figures ii and 12 present the cycle and system efficiencies over the

applicable range of steam to air ratios. The trend in again increasing cycle

and system efflciencies for increased steam to air ratios. The efficiencien

are again ranked in the same order as the fuel heating value of each configu-

atlon. The larger difference in system efficiency (fig. ii) results because

the calculation for light distillate fuel does not have fuel conversion losses.

Figure 13 is a composite of figures i0 and 12 and illustrates the relation

between system efficiency, power output, and injection ratio. The trend is

again increasing power and efficiency with increased injection ratio, with the

magnitude of increase dependent on the configuration. As mentioned in the

design option i results, the percent increase in efficiency is less than the

percent increase in power output because of the additional fuel required for

steam injection.

Figure 14 illustrates the relation between the steam available for process

use and that used for steam injection. Again, there are two sets of results:

one for only the steam raised by reducing the turbine exhaust to the stack

limit; the other for the total steam producing capability that includes steam

raised in the ganifiers. The total amount of available process steam decreases

linearly for increased injection ratios until the compressor surge limit is

reached or in the case of configuration 4 (the light distillate cane) all the

steam raised is used for injection.

Figure 15 illustrates the relation between power, total process steam pro-

duction, and the amount of steam injection. The trends are similar to those

shown for design option 1 (fig. 9) except here configuration 3 in also limited

by the compressor surge margin.

CONCLUDING REMARKS

Both the net power output and efficiency of gas turbine systems can be in-

creased by injecting steam into the combustor of the gas turbine. As an

increasing amountoi" steam is injected into tile combustor of a fixed geometrygas turbine, the massflow through the _urbine increases relative to the massflow through the compressor. This increased relative flow increases the com-pressor back pressure moving the compressor pressure ratio toward the surgeline. The maximumincrease in performance depends on the surge marF,in avail-able to the particular compressor.

The turbomachinery characteristics assumedfor this analysis had a suffic-ient surge margin to accommodatea significant amount of steam injection (upto 50 percent of the compressor flow rate). This steam injection did providesubstantial increases in both power and efficiency. The percent increase inpower is about twice the increase in efficiency for a unit increase in steaminject ion.

Although the turbomachinery in this analysis was capable of accepting a

significant amount of steam, the actual amount of steam available for injection

depends on the steam generating capability of the entire power system. Steam

can be raised by recovering heat from the turbine exhaust products. This

analysis considered gas-turbine systems fueled by either an atmospheric or a

pressurized low heating value fuel gasifier, a pressurized intermediate heating

value fuel gasifier, or by a conventional light distillate. Steam produced in

the gasifiers is also available for injection into the gas-turbine combustor.

in all but two of the power syst_ns considered in this analysis, the maximum

system steam raising capability (through exhaust heat recovery and gasifier

steam) was between 18 and 26 percent of the compressor air flow. This amount

of steam injection resulted in power increases of 68 to i00 percent an,. effici-

ency increases between 32 and 52 percent over the respective cases without

steam injection. The system fueled by a pressurized low heating value fuel

gasifier had a system steam raising capability of 37 percent of compressor flow,

which results in power and efficiency increases of 145 and 62 percent, respec-

tively, over the noninjected case. The percent increase in performance with

steam injection is relatively insensitive to the type of fuel. Steam injection

could apply equally well to the various types of integrated-gasifier - gas-

turbine systems. However, the use of certain fuels or integration schemes

offer a greater potential performance increase.

In an industrial cogeneration application, part of the steam generated by

gasifier and the gas-turbine exhaust heat recovery can be used for steam injec-

tion, and part can be used to meet industrial process needs. By varying the

amount of steam used for injection, the ratio of power to process steam produced

by the system can be easily varied. As stated previously, the power output can

be varied by up to 145 percent for the cases studied here. _q_en the maximum

steam injection rate is used, the steam available for process is zero in all but

three cases studied here. (In those three cases the compressor surge line limit

was reached before all the steam available was used for injection). When the

steam-injection rate is reduced to zero, the steam available for process use is

1769 to 3266 kilograms per hour (3900 to 7200 pounds per hour) per megawatt of

power produced for the cases studied.

i.

2,

.

.

i0

REFERENCES

Boyle, R. J.: Effect of Steam Addition on Cycle Performance of Simple andRecuperated Gas Turbine. NASA TP-1440, 1970.

Day, W. H.; and Kydd, P. H.: Maximum Steam Injection in Gas Turbines.ASME Paper 72-JPG-GT-I, 1972.

Steam Injected Gas Turbine Study: An Economic and Thermodynamic Appraisal.

EPRI AF-II86, Electric Power Research Institute, Sept. ]979.

Fralze, W. E.; and Kinney, C.: Effects of Steam Injection on the Perform-

ance of Gas Turbine Power Cycles. ASME Paper 78-GT-II, Apr. 1978.

_ _' _r '

TABLE I. - FUEL COMI"O_ITION FOR EACIt CONI:I_;UI'_A'IIOH

5pec Jes

I¢0

CO 2

ill2

ICII4

N2

1t28

11120

CHI. 942

Higher heating value

M I/Kg (Btu/lb)

|tower system coP.f].guration

1 2 3 4

_ass fraction

0.2906

.0913

.0116

.0150

.5851

.0005

.0059

0

0.2906

.0913

.0116

.0150

.58_i

.0005

.0059

0

5.42 (2332)

0.6033

,2870

.0281

,0085

,0051

,0012

.0069

0

13,91 (5982)

I

II

iI

i

1.O

43.26 (18 600)

TABI.E II. - GAS TURBINE DESIGN OPE_ITING POINT PARA>IEIERS

Compressor pressure ratio

Compressor efficiency (adiabatic)

Turbine inlet temperature, oc (OF)

Turbine pressure ratio

Turbine efficiency (adiabatic)

Loss pressure ratioa:

(AvlV)duet(__(_

(_P/Plcomb.(_)_(])

(APlPlduct(__(_)

(_P/V)duct(__(_)

(AP/I')HRSG (_) _(_)

Mechanical efficiencyGenerator efficiency

Compressori_let air flo_,K__-(Ib--_1sec \see]

Steam to air ratio

Ii.0

0.846

1093 (2000)

9.735

0.91

0.885

0,0135

0.030

0.0135

0.0135

0.050

0.98

0.96

69,04 (152.2].)

0

aSubscripts refer to duct lo_ations shown in fig. i.

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blltlil_ llli'l, llh. : i4G/llln I;.T,; 'lv).cll. '- I_'nv[/Qin (i.T.; B_iy_tl, lu '" I_'lh, t/i,_vo,i I , I_,llt, l'l. t_hl I:.'l', 18 thl,

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{;o,'< _ I .i,_.c

ox.%'p,e!l t o

lut'l thlw

Y_ll. Iol

l_lli .}/l(i

--- O. ;D<lO'l

'rABI.E VI• - DETAILED PERFOItMANCE

¢(HI l i gltt':|L {oTi

;! - (;as lurbhw

I Iju'lt_d I'I%HII dl|

a l r- b I own

p ros,su r i zL,d

Baslflcr

- (kl_ turblnu

fueled from

11XV F_Pll- b J OWl|

pl't'_ StJ? | _.t'd

Fa-'_( f'| er

- G;ls turbl|1¢_

fu(;h'd wtth a

J[Fht dlstil]atv

( )I H11p rt, s ,_or

p l'c _i:_ll lv

PlI,.

12.42

l ?, (_4

I _.39

1l.o

I1. S_

1/.11

12. (i b

IN,47

IC),U9

tl, 50

1.2,0;.

12.54

1I. 06

{ ', HIIp I'l.: ;i_:iO I 1'

L'II I," _ t'llt.'N'

I"

(1.8.!')

.,_17

•,_04

(I._,:h

.8 _'i

().H4b

. H',2

.8_6

.827

.81.',

.8o4

('Olllp |'t'i,'__11 r

alr ilow,

ii.i,

K,_/:_ve ( I b/.sec')

(_..04 (152.21)

(:( flll[)ll @L of

,Ih" flow

I I1 c t_lll-

pl'p.q:ior

_'l [ l" f [O _,'/

ma l/ma

0.841

.831

.82_

1.0

I

(;asifler

air flow

|:O C Olll-

pressor_lir flow

rat io

ma 2 /mn 1

0.159

.168

,176

Fuel flow

_0 com-

bus_or

air flow

ratio,

mf/ma I

0.248

•2O6

•281

0.074

.079

,085

,090

•094

0.022

•023

.O25

•026

.O28

,029

.030

_t_l_ _0

co_pre_I,()r

air flow

ratio,

&,Ima

0

•042

.077

0

.05

.i0

.I_

,20

0

.05

.I0

.15

.20

.25

.28

Qin.c_ At_nospD.ericgasifier

| and| Clean-upJ and

heatrecovery

A: lineal exchanger

Air

PI ' PaPR,c I

Combustor

' _ t SteamCO0° I: . SJ._9OOOF, 200 psia--

Compressor Oin, GT mf _ j ,

Process I '

Waux_', _ steam ,

"'x"x,, PR c'PRc+3'3 I '

LowBtu fuelgas

O0o F

Steam for processor injection

800F Pump

I

> q(

> d

> =

b 1

Generator

5

6 r/cycle" w_r°ss "wauxOin, GT

'1!_ IHi_e_ ery

7Tostackor

optionalwaterrecoverysystem

300° F

(a) Configuration l: gas turbine with steaminjectionfueled from an air-blown atmosphericgasilier,

Air

._ Pressurized

gasifierend

clean-upand

heat recoveryI_eatt'xchandier

I

1

P1 = PaPR,C

2 Combustor

61_o

,, L

LOw Btufuelgas

, 4 Steam

'S_°j F, 200psia--_

m

Process ,¢steam '¢

¢

_t _

<

Staan_for process W k,,.._

or injection Pump

Heat

recoveryboiler

Tostackor

optional waterrecoverysystem

Generator J

cb)Configuration 2: gas turbine with steaminjection fueled from an air-blOwnpressuriZ_ gasifier.

Figure ,.- S)stem schematics.

Generator

! P!_PaPR, c

Oxygenpl_t

PR,C" PR, C +3';_

Combustor

Steam Ior process 7

or injection..--.. To stack orWater ---'-,-'_ _' optionalwater

N2 recovery systemPump

(c)Configuration 3: gas turbine with steam injection fueled froman oxygen-bloNn pressurized qesi(ier.

Airma

Pa-

PI " PaPR,C

Combustor l mT

' trhs t Steam

"-'q'o0 L 200 sid

I team /<

ne_ Generator 1

'l

Heat

r_overyi:i let

Pump

KI} Conhguration 4: gas turbine with steam injection tuel_ with awaterdistillate.

l tostackor

-----_..®tional waterrecovery system

Fiqure L " Conclu(_ed,

Heat recovery

Ileat exchanger_,\100 _ "1

,Energyunits) . _ '_ .._

Gasitier _ ._._l_z 1.83 Ibsteam/Ibcoal

Steam /I3.04 Ibair/Ibcoal Raw(uelgas'---_ " _-I Steam

|system| system

'-_ t I ,ue_gas_%2/76'_er hea,_og_a_ue)Losse Aux liary(3.8) power 4.0 Ib fue gas/Ibcoal

(1.2)

(a) Configuration1: atmosphericgasifier, low Btu fuel,

(100)

Gasifier

3, 04 Ib air/Ib coal" ",., ] ,_"p(76.o -- a,sedonHHV)Heat recovery ,/ I I I\ 4. 8-- Sensible

heat exchanger-" i

Losses Auxiliary(7.9) power

(2.O)

Steamfor process

1.47 Ib steam/Ibcoal

LOWBtu fuel gas

4.0 Ib fueUIb coal

(b) Config,Jration2: pressurized9asifier, low Btu fuel.

Figure2. - Energy flow paths for fuel supplysystemsof configurations 1,2, and3.

Steam.... ._forprocess;,

_ Gasi,ier _ l_-_165,bfue,llbcoal

Oxygen _ _"Tv '

t _xch.nger- I _ I IBtufuelI _ I \ ;_6 SenSibte )

l Clean-up 1I system II II _-__-_'__.__

Losses Auxiliary

if2.9) poweriI.4)

_c)conliguration _: pressurized _asilier, intermediateBtu (uel.

Fig_reZ, -Conc(uded.

14

/a ,_ 10- /

" / _ Surpe

_I lineEo

_ 90 percent_,of design

Elficiency,"0

! 0,8oz818

838

.846

.844

,838

•826

• 782

""--Design speed_eed

Mass flow parameter, m TIP

{a) Compressor

64--

Over the pressure ratio rangeconsidered,the massflowparameter mV_-_, was assumedconstant with a value of 236.12.

tO,.

E

52& -- /

/I

--//

-I!

___.J__l_.....4

.._....! Over pressure ratio range considered

the turbine massflow parameterandefficiency were assumedconstantwith _values of 62.18and O.91, respectively.For design option 2 the massflow para-meter value was 53. 12,

Massflow parameter_---- Effeciency

1 ] I I J6 8 10 12 14

Turbirlepressure ratio

(bl TurLine

Figure 3. - Compressorand turbine characteristicsfor designoptions ! and 2,

.8O

.60 ,_.u

.40"_

,2O

1>O

L3

.- _. _;u _ ,o'-3 23

I I _I 'i i

"\,,','\,_ _

\,, \\_,_

Iue3Jad '10 lJ!01l'OUt,*i '_(:)Ue!3!IJ0 al_/_3

'G

a_

_,_ _._

N _

,_.E;E _

_.= _,"_

bO C]

Surge.limit

Fueltype

-------- Lc_ Btu atmospheri(. 9asi(ier(con(jkluration1)

- _ Low Btu pressurized gasifier,40 --

Upper three _.,:1',_1 I¢_,u[ts (configuration 2)"'_ includ(_ _tealll ,IV;.li}aOl_ITOIt_ _--_ Intermediate Btu pressurizedgasifier

_ ,.jasifiersand turt_ine (configuration3)-- .. _--_ LightdistillateE, _ --" -,_ u^haus'_ , (configuration 4}

_o" •

0L- __ I _."___ _ ......-1130 20 40 oO _0 I00 I'20 140 I(_0 )._,Ox,O

Pre_es_steamproOuction,Iblhr

Fi!Iure_,.- Relationbetweensteamu',edtoincreasepowerand thatavailableforprocessuse,S_eal)1 telYl_Dlatt)te and pressLl(,,', 90(]0 [ a,II_d200 psi,

._0_ _'L,3 V Compressorsurge• 5 , Steamto Coml)ressor

, air flow ratio, msJma Fuel type, ,' _ t.OWB_,tJa_mosphericgasiter

49

I-- Iconfiguration 11'_'? _- _ Low Btupressurize_gasitier

(contigurat[on2l

4 _ •,. 25 _--_ tnterltddiateBtu pressurizedgasifier0_._k,_.25 "_ (configuration3)

I'%,, "_. _.20 .... Light distillate,,,_"_ _ ,20 '_ (configuration4)

,..] ",__ \ ",, ,,,<

\I ",, % ", %,0

L ,150 20 40 O0 _0 lot] 120 140 160 180),,103

T_9,alpIc,_::_', :.teo_qprudu_.[iolL Ib/hf

Fiqure q. - Vouet_eration s,,st_'m;)_,rlor_m_ntetar 11_' hxml t_rbomaclfiner_size ol design _tion 1for tl_e ,,,,_rh)_s_'uels, Stea_ te_qper._tureandpre_,ure, 9000 an_ 200 psi.

'I

i i i I

5O

,.10

2O

V0

CompressorsurgeLimit of steam raising

capability In turbineexhaust

Fuel type

Low Btu pressurizedgasifier(configuration2)

Intermediate8tu pressurizedgasifier (configuration3)

Light distillate (configuration4)

-- $7

.L_

lo---- I i I.I ,2 ,3

Steam to compressor Ilow ratio, mslma

Figure10. - Effect of fuel typeand steaminjectionon net poweroutput lor the fixed turbomachinery sizeof design option Z.

45--

40---

.E 35g

a_

_70

_°lm

,,0

/,' ,,,0

s /

/ /'

25- t .I 1.1 ,2 .3

Steamto compressor air flow ratio, ms/ma

ktgure |1. - Effectof fuel typeanclsteaminjection on cycleeft;ci_m:y fixed turbomachinerysizeof designoption£

CompressorsurgeLimitof steamraising

capabilityin turbineexhaust

Fuel type

LowBtupressurizedgasifier(configuration2)

IntermediateBtu pressurizedgasifier (configuration 3)

Lightdistillate (configuration4)

ORIGINALt" ".' i".

• .i

Basmlon distillah llllV;45 - off+ire c_Jl Io di_dillilte

conversion eltici_lcy

n_', irlclucled t '_

/"a /

5_

C /

V

0cOllllJressor surge

Limit ol steam raising

cap_lbilily in turlfineexhaust

ruel 'type

tow Blu pressurized gasifier

(configuration 2)

Intermediak, Btu pressurized

gasifk'r (configuration 31

Ligllt distillate (configuration 41

t+--- +.I....... L ........ ]• 10 ,20 .30

Steam to tomlJr('ssor air flow ratio, mslm a

figure Id, - Effect ol lu+,l type and steam injection on syslem el-Ikti_l'..v lot lht' hxed turl)omaclfiner)' size ol design option _.

,I0

8

35

+.o..+."30

u_

25

pi+

/ ..-.Steam to compressor

]". lo" air flow ratio, rushy+a

.... +/OS V

I

/+.15/

/'.to/

-]'. 0.5 ....

't, +Y'+ ------

')0 40

Net pm_er, M_','e

[igure t3. - Perfor_,_ance ol .qas turlfine power cycles lot lhet<xedlurLm;_m,..him'r¥ sizt: of design option 2 for various

Iklt'lS and steam-injedion ratios.

Compressor sunje

Limit or steam raisingcapability in lurbineexhaust

Fuel type

low Btu pressurized gasifier

<configuration 2+

Intermediate Btu pressurized

gasifier (configuration 31

Li(lht distillate {configuration 41

I ,11

/ • ]lJ

t

o

\

X_\ \\'N X

V CompressorsJ_rcjo/hnll

I.uol type

LowBtu Pressurized gaslflor(_nfiguratlon 2_

.... Intermediate8tu pressurizedgaslfier 4configuration 3)

,_ """ LIgl_ldistillate (cnnflguration 4)\\\

',\ \

_.,. X .' Includes process steam

"l_._ _ .' _; avallabl_ Ire _ gaslfier"X_ \\. "_dturotnee,maust

_t,.,,,,p,',_,J,Jce_ "_._*. x xfro,,,",..nee*J oust-" -\

.... (.......... _ ..... \\.X X

_'0 40 60 80 ]DO 120xlO3Process steamPr_uction, Ib/hr

li,lutr14,- r<elalionl>elween.geamuseclIo Increasepowerand thatavaih_b(,for Process use, Design _tion 2, steam temperatureandpros_(_,e.9000 F, _nd ?[_)psi. '

4II'-

Compressor surge limit

Fuel type--'---" Low Bfu Pressur!ze_ gasifler

(configuration2)"-''_ Intermediate8tu Pressurlzea

gasifler(configuration 3).... llghl distit/afe (configuration4)

L_3(: , \

x_,_ _°\ \x_)o

,_o ..... J..........--L---___L__0 20 40 OO 80 IOO 12OxiO3

Fo_l process steamproduction, Iblhr

I_!lur_, 1_. - Co_eneration systemPerformance for thefixed turbo-,'_acl_tne,._,she of d_sigr_option 2 for the various fuels, Process_tre,_mtemperalure and pressure, 900o F and 200 psi. TotalP,rJces,_ steam include,_ that availabe from gasifier and turbineL'_IMUS(.

NASA 'I'M-tile, 11 ]

4 1,_., 4rid ._ulHdh'

(')l; I,'-I)ESIGN ANA I,YSIS O1.' A ,]AS Tt:IUHNI.; I_OWI.'ItP LANT

AI_t;MI.:NTEI) BY STEAM INJEi'TION IISIN(; VAI/IOUS FUELS

llohevt J, ,_l.¢'hl

9 ,_vHnrnun 90rg_mt,Jtlon N,Jrne and Addrev,

Nati,mal Aer.nautirff and Slmve Admlni,_t.'athm

i.OV.'i.'-; l_o_e;H'ch (._(.,lltt?l"

(.'loVOhllVl, ()_Jo 4413,5

Na|l_ll:t] Aerot_|utit'.'* and Slmvo Ad|nini:drati,,i

W;t,'ihil_;h)n, I). C. 2054(;

1,'

11 )

3. Hec,p_ent'i (._talo9 No

5 RClX)H Date

Now_mber 1980

6. Performing Otgqnit_ltion Code

_/78-46-12

8 PeHottrun 00l_*ttllttlhiqtl Fiefmtt NO

E-609

10. WoH_ Unit No

1 1. Contract or Grant No

13. TyI_ of Repor_ and Permd C,oveled

Tochl_ical Memorandum

14. Sponsoring A_ncy {',ode

|l, Ah'A',lCt

The results o! an analysis to (2stimnlo the .fi-d,,_Jt_,n performance of a specific gas turbine

i){,wcrl)lant ,qugmol}ted ))y ,_h.til}} Jtu_!('tJut} art. i)rosentod, ltosults are con|pared using coal-

d,,J'Jvod low ;ll}(I ]nh,rn|(_diate h('atinl,' valve fuel hm_*'s and ;} conventional distillate, The results

llfflJt,_llt, th,d steam illJot'tJoll ('ouid t)|'OVJr][ ' _ul)...lal]tia] im'roases in both power and efficiency

wilhh] the availn)_lt, col])])l.,,,,_st)|, ,_url_e DI_IF_Jt). Tht' l'r,,'_ulls also indicate that these perform-

am'o g;tins are rolatJvely in,_vnsitive a,_ t(_ lht, type t)f fuel,

I ...............................t :' _.'e( '_oI_, (S_.¢Jqe'_h,d by Autho_(S}l 18 Draft,but=on St=tement

' St,,anl injo('tiol_ I.!ncla_sified - unlimited

I (;;t," t_,ll'}llllO_ 8"I'AI_ Category 44

_" ( ",_{l*hil|o(l ('yc 1{',_i._ .rit_._,,,t,('I,_,_,_ (Of th'_ /e$'l_iI} T20 _.,tx,rd) (.]t,¢ssd (of th,s pog_ 21. No of Pages

t :n(' l._,_._it'i od | i'm' las,_t fit, d

22 Pr,ce"

' F,:: _h _'_ tht N,_t_)m, l,,,l_.,,,, i,"_,_"_d,o;__,,':v, ,' Sp,.Li?,el_i Vl _lI_[a 22161

National Aeronautics and

Space Administration

Washington, D.C.20546

Officia! r llinelis

Penalty for Privato Use, $300

SPECIAL FOURTH CLASS MAIL

BOOKPo=tag_ and Feet PaidNational Aeronautic, and

Space AdminiltrationNASA451

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I I

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